Final Report Summary - HI-WI (Materials and drives for High & Wide efficiency electric powertrains)
Executive Summary:
1 Executive Summary
Presently, drives for Fully Electric Vehicles and Hybrid Electric Vehicles develop their highest efficiency of around 93–95% within a speed range of usually 1/4 to 1/3 of the maximum, and at an ideal torque, whereas in real-life driving cycles the motor operates at a wider range of speeds and at partial load, resulting in much lower efficiency. The Hi-Wi acronym is derived from the project target of developing an electric architecture with both a higher efficiency and a wider application range, so that the vehicle can operate efficiently in all operating conditions
The Hi-Wi project has developed advanced electric traction motors for electric vehicles through the application of holistic design across magnetic, thermal, mechanical and control electronics/algorithms in line with real-life use rather than a single-point “rating”. This was achieved through the provision of advanced modelling and simulation tools, for both materials, and electrical systems under various driving cycles relevant to the EU consumer.
The anticipated growth of the electric and hybrid vehicle market means that the subsequent demand for permanent magnets that are central to this technology is certain to grow dramatically. Considering the resource distribution of rare-earth metals, European car manufactures have to face the problem of restrictive and vulnerable supply chains for rare earth metals, since most reserves are outside Europe and more than 95% of the production is in China or in the hands of Chinese companies. This has already led to a sharp increase in price for rare-earth metals (such as Neodymium (Nd), Dysprosium (Dy) and Terbium (Tb)) because they are essential additives to produce high energy-product magnets. A significant problem for the EU is that it holds no rare earth reserves. There was therefore a pressing need to develop advanced motors for FEV applications that relied less on rare earth elements, but could still remain competitive with the growing competition from China and elsewhere. Hi-Wi coupled its novel design approach to breakthroughs in materials and manufacturing, winning size, weight, logistical and cost savings through the use of nano-scale modelling techniques which led to a better understanding of the means by which rare earth materials could be applied leading to greater levels of resource efficiency. Research completed by Hi Wi has led to magnetic materials advances, that have created superior magnetic field strengths with reduced reliance upon rare earth elements, reducing exposure to their economically-vulnerable strategic supply chains. Magnet production was achieved through the adoption of nano-scale magnetic material usage and a step change in the manufacturing processes for magnetic materials with savings of some 81-84% in Dy content, and an overall saving of 40% in rare earth consumption for FEV powertrains.
The new technologies developed in the Hi-Wi project will secure important improvements over current motor and vehicle architectures, such as delivering higher energy efficiency (i.e. more power with less battery consumption) over a wider spectrum of rotating speeds, and decreasing resource dependency on rare earth materials. The motor architectures and the innovative materials developed in the Hi-Wi project have the potential to reach way beyond the electronic vehicle market. Permanent magnet machines have a paramount importance in many other fields, such the as core of the electric m used in all wind generators, industrial fans, blowers and pumps, machine tools, household appliances, power tools, and disk drives.
Project Context and Objectives:
2 Project Context and Objectives
Electrified mobility is currently a top priority in the US, Japan, China, Korea and EU. It promises to introduce a radical industrial change in our society, as new technologies and infrastructure are put in place over the next two decades. The transition phase is now starting, with a growing awareness that the underlying technology to implement electrical mobility is reaching a sufficient level of maturity. There is now a push at many levels (global, EU, national, organisational) to refine and implement enabling technologies and systems so as to effect a platform for fundamental change to our road transport paradigms and to embrace the possibilities promised by the transition to electrical vehicles. In the context of burgeoning vehicle electrification, the EU now has an opportunity to compete effectively in a global context. The strengths of EU innovators in embedded systems design, nanoelectronics and systems integration must be urgently exploited to be assured of a significant European stake in the massive market that is set to emerge in the coming decades. The outcomes of the Hi-Wi project enhance the EU’s capability to exploit this opportunity. The route towards fully electric vehicles will be more and more motivated by considerations of resource efficiency both in terms of material use and energy savings, in addition to the development of city regulations. EU policy and regulation are further driving forces towards better environmental standards for personal and business transport. Energy efficient vehicles have a major role to play improving environmental standards and the electromobility is a major enabler of energy efficiency strategies.
Lighter and smaller sized cars could be designed with an ideal powertrain requiring less than 60Wh/km and a reduced overall battery pack. The path toward low cost electrification is a complex one requiring, as in Hi-Wi, new approaches to vehicle design as well as a shift to radical improvements in powertrains. Hi-Wi outputs will contribute to the development of a European standard reference technology platform for electric vehicle design, which contains architectures, models, methods, and tools for real time embedded system development, verification, validation and testing. As described in the DOW, the three-year HI-WI project had the following objectives:
• The prototyping and demonstration of innovative topologies and concepts for FEV/HEV powertrain platforms, including in-wheel and engine-integration examples, with nominal power in the range of 3-6 kW and showing high efficiencies over the wide torque/speed range demanded by real-use driving cycles.
• Innovative approaches to the holistic design and modelling of rotating magnetic machines tailored specifically to the in-use conditions of FEV and HEV drive cycles.
• Micro- and nano-scale materials advances to create superior field strengths with reduced reliance upon rare earth elements and their economically-vulnerable strategic supply chains
• Micro- and nano-scale manufacturing advances to create permanent magnets and integrated assemblies having ideal geometries, reduced size and weight, and improved mechanical, magnetic, and thermal properties
• The development of advanced magnetic modelling tools and a multi-physics modelling environment tailored towards the requirements of EV powertrain applications
• The development of safety-first fault-tolerant adaptive electronic controllers for efficient bidirectional coupling between the drive and the accumulator pack
• Guidelines, standards, IPR and experience upon which to build a world-leading EU position in the economic mass manufacture of motors to exploit the global uptake of FEV and HEV mobility
Hi-Wi was organised as 6 technical work packages with two demonstrator streams. The Hi-Wi project brought together a particularly able mix of global companies, research institutions and SMEs to form a high impact research activity with deep experience in new enabling technologies for the production of powertrain systems. To deliver its objectives, the Hi-Wi project embraced the following topics:
• Embedded control systems architectures for electric vehicle and further domains based on distributed propulsion and distributed energy networks.
• Electrical power distribution architectures including related functional units.
• Information system network architectures.
• Sub systems functional design, and properties allowing reusability of software.
• Embedded systems, electronics, and software for functional module design and integration.
• Electric vehicle architecture definitions and optimization.
• Electric vehicle networks design and optimisation.
• Electric vehicle multi-domain analysis.
• Software and mechatronics design.
• Electric vehicle distribution systems design and manufacturing.
• Documentation and diagnostics.
• A forum to evaluate breakthrough materials and processes in the context of in-depth automotive applications expertise.
Intensive interaction between Hi-Wi partners was an essential ingredient in meeting Hi-Wi objectives. Breakthrough ideas in drive topology and materials synthesis generated by the university research base at Sheffield and Cambridge were tempered and informed by the global powertrain players Fiat, Siemens and STMicrolectronics. Accordingly, these global powertrain players have been offered a breadth of innovation, ranging from well-characterised engineering developments through to more speculative materials synthesis, from which they selected an optimum blend as the project progressed. This ability to choose and steer results to an appropriate Technology Readiness Level was essential to mitigate the risks of technology adoption. Agile SME capabilities in advanced modelling and simulation, at IPM and CEDRAT, brought a level of confidence to the adoption of the new ideas, condensing the normal timescales for optimising the new technologies to be implemented, yet providing the level of confidence demanded by the traditionally conservative global players. The success of developing and delivering technologies includes risks that are normally present in any R&D project involving the full-scale design and build of new technical systems within tight time-frames. The HI-WI programme was specifically constructed to have a “portfolio” of work balancing the high risk of speculative research against the more predictable progress of engineering development.
Project Results:
3 Main Scientific and Technical Results
3.1 Overview
At present, motors for FEV (Fully Electric Vehicle) and HEV (Hybrid Electric Vehicle) applications develop their highest efficiency of around 93~95% within a speed range of typically 1/4 to 1/3 of the maximum rotating speed, and at an ideal torque, whereas in real usage - in the majority of driving cycles - the motor operates at a wider range of speeds and at partial load (low torque) resulting in much lower efficiency. Hi-Wi addressed these issues by developing a novel powertrain approach to enable high efficiencies over a wide operating range.
There are restrictive and vulnerable supply chains for the rare earth element (REE) materials required to manufacture high magnetic strength components. Hi-Wi addressed this problem by developing new magnetic materials with reduced rare earth content.
To optimise powertrain design for Hi-Wi performance, the development of advanced magnetic modelling tools and a multi-physics modelling environment tailored towards the requirements of EV powertrain applications are required. Hi-Wi developed new modelling and simulation tools for power systems and magnetic materials.
3.2 WP 1: System Partitioning and Specification
The objectives of this work package were
• Partitioning of the electrical drive train and preliminary functional specification for the defined subsystems
• Detailed specification and related constraints (mechanical, thermal, electrical) of the drive train subsystems against the overall powertrain/vehicle target performances
• Study of the influence of various electrical machine architectures and electronic drive stages on the overall system performances, and on the efficiency, size and cost requirements.
• Definition of guidelines and design strategies to address high efficiency over a wide range of electric powertrain operations
• Definition of a strategy to apply the project developments on a test-bench and on a demonstrator vehicle
3.2.1 Work Undertaken
WP1 was central to the Hi-Wi project, as it established the design guidelines for achieving high efficiency over a wide torque/speed range based on a holistic examination of the energy distribution of the envisaged Hi-Wi power train. The work package was divided into 6 tasks:
Task 1.1 Overall Drive-train specifications and constraints (CRF, SIEMENS, USFD, STM)
The drive train architecture was analysed by means of software modelling tools against OEM requirements for Full Electric Vehicle lower-end classes A and Sub-A, (also called “micro car”) which have relatively low overall rated power.
Task 1.2 Wide-efficiency powertrain design guidelines definition. Trade-off studies and integration strategy (CRF, USFD, CEDRAT)
This Task established an integration strategy between the various components of the power train unit using a design framework that was established to address the design of a drive train having overall high efficiency over a breadth of real-use conditions.
Task 1.3 Power conversion and distribution subsystem specification (STM, USFD, CEDRAT)
The requirements for the power converter were defined in terms of DC-Link voltage (outcome of Task 1.2) max power (Outcome of Task 1.1).
Task 1.4 Electric motor subsystem specification (USFD, CEDRAT, SIEMENS)
The traction motor was specified against the rated and peak power, and torque (outcome of Task 1.1) and the winding voltage (Task 1.2) with particular care being applied to the definition of guidelines for the modularity of the electrical machine to make it suitable for the widest possible application range.
Task 1.5 Automotive interface specification (CRF, SIEMENS, STM)
Guidelines for electrical machine, gear and inverter integration were detailed for further analysis and the development of a powertrain system, composed of independent globally optimized accumulator-electronic drive-motor blocks. Mission profiles for urban/extra urban and up/down hill cycles were derived from statistical analysis upon real-world data acquired on selected routes, in addition to the development of a methodology to compare different mission profiles.
Task 1.6 Magnetic material properties specification and electric motor design guidelines definition; Verification & Validation strategy definition (CRF, UCAM, USFD, IPM)
UCAM worked with USFD to specify the required dimensions for magnets to be used in the new USFD motor designs and agreed on a target of 20 kOe for the coercivity of the new magnetic material to be developed in WP2. After its manufacture, the new reduced rare earth magnetic material was assessed using a permeameter in order to characterize magnetic behaviour over the temperature range of interest. The coercivity recorded at room temperature was 19.6 kOe. This met the requirements of USFD. The effect of the new magnetic materials on motor performance was explored through simulations carried out at USFD.
3.2.2 Scientific and Technical Results
Specification for the drive-train and Integration Strategy
The main data for the preliminary specifications of the traction electric motors were defined through close consideration of the constraints and requirements of the target vehicle. Following the exploration of possible transmission solutions, the powertrain architecture was established as one ‘central’ e-drive for the front axle and two ‘distributed’ e-drives to the wheels for the rear axle. In addition, overall guidelines for the traction e-drive integration were developed, including application requirements (environmental conditions, electromagnetic compatibility (EMC), expected operating life and protective measures) for an effective usage of the e-drive components of the powertrain.
Inverter and Motor Specifications
The design specifications of the motors and power converters based on the chosen vehicle power train architectures were based on two defined driving cycles (NEDC and Artemis Urban) and the requirements for acceleration and hill climbing. The effects of gear ratio and cooling conditions on motor sizes were also considered and the total energy consumptions over the two driving cycles were quantified. This work provided the basis for sizing the inverters and the battery for a given range requirement.
System partitioning and specification
This provided the framework for the Hi-Wi project, it established the design guidelines for achieving high efficiency over a wide torque/speed range based on the analysis of the energy distribution of the Hi-Wi vehicle power train. The work showed that the energy consumption of a traction motor can be represented by 12 discrete points, over which the design optimisation for minimum energy loss can be performed effectively and efficiently. This was shown to dramatically reduce the computation time required for the optimisation process. The work also demonstrated that ~73% of energy over the NEDC is consumed in high speed and low torque regions and it was therefore essential that the motor design should endeavor to match the high efficiency region of the traction motor to the high energy consumption points. Trade-off studies on the power train gear ratios were also developed, indicating that:
• Increasing the gear ratio from 4 to 7 reduces motor weight, size and cost by ~40%, but does not compromise the motor efficiency
• As gear ratio increases from 4 to 7, the transmission efficiency decreases, resulting in an overall reduction in efficiency by ~3% over the NEDC cycle
• Reduction of motor costs through using a 7:1 gear ratio may not offset the increase in battery cost for the same range requirement
• Gear ratio has a negligible influence on inverter VA rating, cost and efficiency
The work confirmed that the optimal design and efficiency of traction motors are dependent on a driving cycle. For the permanent magnet machines, since its high efficiency region is relatively wider than other machine technologies, this dependency is less significant. In general, to achieve high efficiency in the NEDC, the motor would have to be optimised to have high efficiency in low torque and high speeds. In contrast, high efficiency operation over the AUDC requires high efficiency in high torque and low speeds. By exploiting the distributed driving architecture of the Hi-Wi power train, figure.1 the best results would be obtained by optimising the front motor against the NEDC and the rear motors against the AUDC, thus, maximising the High and Wide efficiency operating range. The findings of this study were seminal for the subsequent design optimisation of the complete HIWI power train.
Validation and Verification
The standard driving cycles normally used only approximate the real scenarios that cars face over their service and usually fail to take into account different driving styles. Accordingly, the Hi-Wi project broke new ground by generating new mission profiles, devised through statistical analysis of real-world data collected over various scenarios with different driving style and traffic conditions. Three different scenarios were taken into account, they were called Urban, Extra Urban and Up Down Hill (figure.2). The car used was a FIAT 500 Hybrid. Mission profiles were defined from real data acquisition studies in order to develop test conditions for the new Hi-Wi motors.
Figure 2 Up Down hill driving cycles use in the validation trials
3.2.3 Impact on other Work Packages
WP1 was of great importance in that it defined the basis on which all technical specifications of the Hi-Wi project were developed including:- Specification for the drive-train; Design guidelines definition; Integration strategy; Inverter specifications; Guidelines for modularity of the electrical machine; Tractor motor specifications; Guidelines for integration of the power train; Mission profile definition from real data acquisition; Guide line for route selection; Methodology of comparison of different mission profiles; Specification and assessment of the new reduced rare earth magnetic materials; and simulation of the new rare earth magnetic material on motor performance.
3.3 WP 2: Magnetic Material and Manufacturing Process Innovation
Delivering significant reductions in rare earth element usage, whilst producing magnetic materials with the required levels of magnetic performance for FEV applications, was one of the greatest challenges of the Hi-Wi project. Accordingly, WP2 was not only ambitious but was also the work package with the highest risk factor. Its objectives were:
• To design & manufacture a laboratory based laser assisted supersonic powder deposition apparatus for the production of full density magnetic materials with geometrical control for the production of net shape magnetic components with reduced rare earth content
• To characterise the magnetic characteristics of laser annealed magnetic materials
• To establish a novel production route for nano crystalline rare earth magnetic materials utilising high speed laser annealing of ribbon or supersonic powder deposits.
• To fully characterise the new production route through a comprehensive parametric study of production variables for each magnetic material employed.
• To produce prototype high performance permanent magnets, with lower levels of rare earth consumption for application in a demonstrator Hi-Wi motor.
3.3.1 Work Undertaken
WP2 was divided into 6 tasks:
Task 2.1 Novel process route for the control of nanostructure in thin magnetic films. (UCAM)
Laser based annealing of iron rich NeFeB material was developed in order to produce a nano-exchange coupling effect that could allow local control of nanoscale grain structure leading to a magnetic material with high coercivity and reduced rare earth content.
Task 2.2 Characterisation of annealed films (UCAM,USFD, IPM)
The thin film magnetic materials produced in Task 2.1 underwent structural analysis using TEM, SEM and XRD to characterise their nanoscale features. Their magnetic properties were determined by hysteresis measurements and data generated here was fed into the magnetic simulation models developed by IPM.
Task 2.3 Production route for amorphous rare earth magnetic powders. (UCAM, IPM)
Spin casting of iron-rich liquid NeFeB droplets was used to produce amorphous powder flakes suitable for application in the magnetic deposition trials of Task 2.4. Structural characterisation of the resultant powders was undertaken using TEM, SEM and XRD analysis.
Task 2.4 Local in situ deposition of magnetic materials (UCAM, USFD, IPM, CRF)
This task developed an experimental deposition apparatus for magnetic powder feedstock produced in Task 2.3 with subsequent laser processing of the magnetic deposit to refine its magnetic properties.
Task 2.5 Characterisation of the deposition process for magnetic powders (UCAM, CRF, SIEMENS)
This task explored the optimum process conditions for depositing magnet structures on a range of substrate materials and geometries as defined by the requirements of WP3. These bulk magnetic samples were analysed for rare earth composition and magnetic characteristics.
Task 2.6 Magnet Production (UCAM, CRF, SIEMENS)
During the final 8 months of the project the materials and production system developed in Task 2.3 and Task 2.4 were employed in the creation of a number of test magnets as defined by the requirements of WP3 and used in demonstrator drive 2, a specially-built front motor for the Hi-Wi drive train. Particular emphasis was placed on the production of magnetic materials with reduced rare earth consumption without loss of magnetic properties.
3.3.2 Scientific and Technical Results
Production route for exchange coupled magnets
The key reason for this work was the drive to reduce the amount of rare earth material which is required to make the magnets in permanent magnet machines for use in Hi-Wi automotive traction systems. Improving the magnetic properties of the material and reducing the volume fraction of rare earth elements used was realised through the use of exchange coupled field techniques. Work outputs here identified a process route for the production of nano-structured magnetic materials. The primary work carried out an extensive study of the production of nano-structured and nano-composite rare earth magnet materials and the potential process routes to produce bulk magnets in quantities suitable for the creation of magnetic components for Hi-Wi motor designs.
Creation of optimised magnetic properties
Melt spun ribbons of amorphous NdFeB material were used in studies of laser annealing in order to assess conditions required for successful development of exchange coupled effects. The depth over which annealing could achieve the required nanostructures was determined through a range of experimental assessments. A series of samples of amorphous ribbon were annealed at differing powers and specific exposure levels while the thermal histories they experienced were recorded. The demagnetisation curves of the resulting samples were measured using a vibrating sample magnetometer and a selection of samples were examined using transmission electron microscopy in order to gain a better understanding of the nanostructures produced, as shown in Figure 4. Following this, the annealing process was tested and validated with a NeFeB composition with iron enrichment in order to develop an exchange-coupled magnetic structure suitable for application in Hi-Wi motors.
Production Route for Magnetic Powder
Gas atomisation was identified as the best route for amorphous powder production due to the need for spherical powders that were necessary for the deposition process employed. Magnequench Ltd, UK, provided modified gas atomised powders, 30% of which were sized sufficiently to meet the critical cooling conditions necessary for forming amorphous powder. This powder fraction was confirmed as amorphous through the use of x-ray diffraction techniques (XRD).
Magnetic Properties: Laser annealing of in-situ depositions
The proposed process route for the deposition and annealing of amorphous NdFeB powder was established early in the project. Apparatus for the laser annealing of wide areas of amorphous material was designed, constructed, characterised and demonstrated. This equipment allowed the relationship between thermal history and magnetic behaviour to be established more accurately than the early tests in D2.1 and D2.2. Magnetic performance was optimised by repeated pulses (up to 20) which raised the temperature of the material to 800 °C. Material annealed by repeated pulses showed increased coercivity relative to both single pulsed and furnace annealed material. The experimentally determined thermal history required for annealing was used alongside a model of the thermal history of a laser annealed amorphous layer to determine the appropriate deposition strategy for the laser annealing of successively deposited amorphous layers of Iron rich NdFeB in order to generate a bulk nanocomposite magnet. Novel deposition of NdFeB proved to be extremely difficult, despite many attempts being made, the majority of the early trials were unsuccessful. A modified deposition process was then employed with much greater levels of success. The magnetic performance of the new deposits suggested that the NdFeB structure was undamaged by the deposition process. The electrical properties of the metallic binder materials limited the potential application of this approach. These issues were addressed in an extended set of trials in order to address the very challenging issue of rare earth element reduction.
Magnet Production Route
The consolidation of amorphous precursors to allow the production of bulk nano composite magnets via the rapid laser annealing of successive layers of material proved to be unsuccessful. Accordingly, an alternative route to the production of bulk high performance magnets with reduced rare earth content was identified. This route opted for reducing the amount of Dy required. Dy is used in rare earth magnets to provide elevated Curie temperatures, a material characteristic essential in automotive traction applications when motors are driven with high loads and low speeds. Moreover, mimimising Dy content is desirable due to the fact that the cost of Dy is significantly higher than Nd and its supply is also relatively insecure. Because of this, the small additions of Dy present in magnets which need to operate at up to 150 °C can cost the same amount as the much larger fraction of Nd present in the magnet. The work package demonstrated the deposition of a controlled amount of Dy on to the surface of NdFeB magnets with very low levels of Dy the bulk material. By diffusing traces of Dy into the thin surface layer of sintered magnets by vacuum heating, a functionally graded magnetic structure was produced. Subsequent tests revealed significant improvements in their coercivity levels and therefore their maximum operating temperature to the levels achieved through the addition of ~ 5 times more Dy via conventional magnet production processes. This was a major achievement, and resulted in record breaking low levels of Dy consumption.
Production of Hi-Wi Magnets
Reduced rare earth content magnets were delivered to the University of Sheffield for use in the Hi-Wi front motor. The NdFeB based magnets used in the Hi-Wi motor were produced via the production route developed in Task 2.5. This resulted in magnets with an 84% reduction in Dy content when compared with conventionally produced material of comparable coercivity while at the same time giving an increase in remenance relative to conventional material (allowing for improved operating efficiency under high torque operating conditions).
3.3.3 Impact on other Work Packages
WP2 was of great importance to the Hi-Wi project in that it defined the basis on which new Hi-Wi motors could be developed in WP5 with significant savings in Dy consumption (84%) , and an overall reduction of rare earth consumption (Nd + Dy) by over 40%. It also provided essential material data for the development of magnetic simulations in WP3, and led to the validation of WP3 simulation outputs through the testing of Hi-Wi motor performance in WP6. Overall, the outputs of WP2 are far reaching with significant advances in European magnetic materials knowledge and application potential far wider than those originally envisaged in the Hi-Wi project.
3.4 WP 3: Powertrain Design and Simulation
The objectives of this work package were
• To establish multi-physics based modelling techniques for EV power trains.
• To develop multi-scale modelling tools for design and optimization of high-performance nanocomposite permanent magnets
• To develop computationally efficient algorithms and tools for system design optimisation of EV power train components with due account of multi-physics interaction.
• To perform comparative studies of electrical machine technologies (such as permanent magnet, induction and switched reluctance machines) for EV traction applications in view of anticipated price increase of rare earth permanent magnet materials.
• To develop high power/torque density and low cost brushless permanent magnet motors with high efficiency over a wide torque-speed range for EV traction application.
• To perform design optimisation of developed machine topology/technology using current state-of-the art and newly developed permanent magnet materials.
3.4.1 Work Undertaken
WP3 pervaded throughout the Hi-Wi project, as it established multi-physics modeling techniques for most elements of the power train including, magnetic materials, EV power train components, motor designs, and design optimization of machine topology. WP3 was divided into 6 tasks:
Task 3.1 Modeling of electric traction drives (USFD, CEDRAT, STM, CRF, SIEMENS)
This task provided the underlying definitions and strategy for the design and simulation of the electrical, electronic, thermal and mechanical dynamics of electrical power trains for EV propulsion, together with the defining of design methodology, tool integration and data flow control. Electrical power train component models included the e-motor, power electronics inverter, DC-DC converter, battery, and on-board vehicle power network, etc., with different levels of fidelity and abstraction, all of which were gathered and developed drawing from existing knowledge and expertise within the consortium members.
Task 3.2 Methodology and computer tools for magnetic material design and optimisation (IPM)
The development of methodology and computer tools for multi-scale modeling, design, and optimization of magnetic, mechanical, and thermal properties of nanopowder-based magnetic composites was carried out in this Task. An effective combination of first-principles, micromagnetic, microstructural calculations, and advanced numerical techniques was used to allow realistic simulations of modern magnetic composite materials with a physically complete formalism, enabling accurate predictions of their magnetic properties.
Task 3.3 Methodology and tools for system design optimisation (CEDRAT, USFD, IPM)
Based on the component and system models established in Task 3.1 and design specifications/ constraints outlined in WP1, Task 1.1 appropriate optimisation techniques, such as sequential dynamic programming, genetic algorithm and particle swarm, etc., were evaluated and integrated with components and systems design/simulation tools, such as SPEED (a tool for theor electromagnetic design electrical machines), MOTORCAD (a thermal analysis tool for electro-mechanical systems), Portunus (a power electronics and circuit analysis/simulation tool), Matlab/Simulink (system and control simulation and design tool) and Flux2D/3D (a numerical tool for electromagnetic and thermal analysis), to form a multi-physics based analysis and design optimisation platform.
Task 3.4 Comparative studies and development of novel machine topologies/technology for EV traction (USFD, CEDRAT, SIEMENS)
The aim of this task was to determine the best machine topology/technology for distributed EV tractions via a comprehensive set of comparative studies and examination of novel machine topologies.
Task 3.5 Design optimisation of PM traction machines (USFD, SIEMENS, UCAM)
For the selected “best candidate” machine topologies, a framework for assessing their performance was established. In addition to conventional specification parameters for continuous operation, this encompassed advanced electromagnetic loss calculations (accounting for the influence of time and space harmonic mmfs and PWM effects) and transient thermal models to assist the design optimisation at the system level. By establishing an analytical framework that incorporates a fundamental and detailed understanding of the torque capability and the loss mechanisms and heat transfer of the candidate machine topologies, the scope for realising high efficiency operation, over a wide region, was investigated.
Task 3.6 Complete electric traction drive simulation (USFD, CEDRAT, IPM)
The 2D finite element analysis based electromagnetic models of the designs in Task 3.4 were integrated with circuit simulations of inverters and accumulators in order to study the overall effect of magnetic simulation, material nonlinearities and harmonic currents on the drive performance. The full electric drive chain (accumulator+converter(s)+motor+load) was simulated by coupled 2D electromagnetic analyses and circuit simulation. The merits and performance of the complete drive chain employing the developed machine technology with both conventional and new magnetic materials were comprehensively assessed and evaluated.
3.4.2 Scientific and Technical Results
Modeling, simulation and design methodology and tools for EV power trains
Modeling, simulation, design methodology and tools have been specifically developed for the Hi-Wi project. Three powertrain models with different levels of fidelity to suit different purpose of study have been established based on the target vehicle data and power train configuration. To investigate the fault behaviour of the distributed Hi-Wi powertrain, a representative model with three independent motor drive units linked together by the vehicle rigid body dynamics and tyre characteristics has also been developed. The model was further extended to cater for two wheel and four wheel distributed power train architectures. This provided an effective means for evaluation of the consequences of drive failures. The theoretical background of each model, and their utilities for targeted applications were demonstrated through representative simulation results. The tool developed for electromagnetic-thermal coupled field analysis was also applied in motor design. A computationally efficient design optimisation method was developed based on in-depth understanding of the energy consumption distribution of the vehicle over the reference NEDC driving cycle. This together with the FE based optimisation tool (Got-It) enabled the global optimization of the traction machine aimed at maximum energy efficiency over the driving cycle being performed.
Comparative studies of machine topologies and technologies for EV traction
The most promising candidate machines for the Hi-Wi project to achieve high efficiency over a wide operating range, were defined following a review of the current state-of-the-art electrical machine technologies and topologies for EV traction. Evaluation of the appropriateness of each machine topology was based on a defined set of figures of merit for selection. The need for cost reduction and for avoiding potential restrictions upon the supply of rare-earth magnets were also taken into account in the comparative study. New concepts, advantages and disadvantages associated with the recent advances in electrical machine research and development were assessed. Subsequently, qualitative and quantitative comparisons among a selected number of candidate machine technologies and topologies were undertaken. The performance of the candidate machine designs are summarised in Table 1.
Table 1
Methodology and computer tools for magnetic composite design & optimization
A model was developed by IPM, Figure 5, to study exchange-coupled magnetic systems (also known as exchange-spring magnets). The demagnetisation process of the model SmCo/Fe/SmCo trilayer was analyzed in the framework of a three-dimensional model based on the numerical integration of the Landau-Lifschitz-Gilbert equation using a SpinPM Micromagnetic Solver. The hysteresis loops obtained for such a trilayer with different geometric parameters allows one to optimise the layer thickneses in order to maximize the energy product. The model was validated through a comparison with the experimental data available in literature.
Development and design optimisation of electrical machines for Hi-Wi traction systems
It has was shown that by employing a dynamic torque apportioning strategy, the overall traction system efficiency with distributed power train configuration could be improved by using dissimilar machine technologies or topologies. In this way, to achieve high efficiency over a wide operating range, the motor or motors for one of the axles should have high efficiency, while the motors or motor for the other axle should exhibit low no-load loss or low idling loss. Based on this understanding, the newly developed fractional slot permanent magnet (PM) machine with low space harmonic content was selected for the front motor, and a permanent magnet assisted synchronous reluctance machine which does not use rare earth magnets was adopted for the two rear motors. Design optimisations against a number of representative driving cycles, such as NEDC, Artemis Urban and the combination of the two were performed with the objective of minimising the energy consumption while satisfying performance specifications, including electrical, thermal, mechanical and volumetric constraints. The physical models for evaluating performance and constraints were established, and optimisation methods and tools were delivered.
The influence of drive cycles on optimisation was also studied. It was shown that the optimization results against the NEDC and Artemis drive cycles exhibit distinct characteristics in terms of torque, speed, and energy loss distributions. Thus the optimization trends for leading machine design parameters such as split ratio, stator tooth width, turn number per coil and magnet usage to minimise total loss over NEDC and over Artemis were very different. For NEDC, the optimum design inclines to reduce high-speed copper loss and iron loss; for Artemis, it tends to minimise low-speed copper loss. Comparing the three optimised motors targeting different driving cycles, it was observed that they all have very high efficiency over a wide toque-speed range, and perform the best in their own target cycle, and with around 0.5% to 1.0% lower efficiency, or 10% to 20% higher loss in the other cycles with respect to the best efficiency. Compared to the motor optimised for Artemis, the motors optimised against NEDC and the combined cycle result in ~20% less magnet usage and a few % less copper usage, making NEDC or the combined driving cycle a preferred optimisation target.
Four fractional-slot PM candidate machines were optimised against the same specifications and constraints and their performances were compared. It was shown that the 18-slot, 8-pole interior permanent magnet machine has the best performance with low permanent magnet usage. This machine topology was therefore selected for prototype construction. The PM assisted synchronous reluctance machine for the rear motors was also optimised and it was shown that this machine benefited from lower no-load loss and low cost with NEDC efficiency comparable to that of the front motor. The two optimised machines formed an ideal combination of the distributed traction system for the HIWI power train. System efficiency maps for three designs are shown in Figure 6.
Figure 6 System efficiency maps for three optimal designs
Optimized magnetic composite 3D structure
The design optimisation route for the assessment of optimised 3D magnetic structures, was performed using both the current state-of-the-art permanent magnet materials and newly developed magnets resulting from this project, using the magnetic, thermal, and mechanical parameters obtained by characterization in WP2, and information on optimized microstructure and micromagnetic properties obtained in Task 3.2.
3.4.3 Impact on other Work Packages
WP3 provided the basis on which the optimum motor designs and configurations were determined which fed directly into WP5. The results of magnetic modelling work supported the experimental trials of exchange-coupled magnet production that targeted optimised grain sizes in the laser annealing of amorphous magnetic materials in WP2.
3.5 WP 4: Power Electronics and Control System
The objectives of this work package were
• Define an electronic architectures based on mechatronic modules solution to ensure a highly integrated, energy efficient power electronics subsystems for power conversion
• Design and development of system-based chip, planned to embedded fail-safe concepts, for MOSFET inverter bridges planned to definite brushless motors;
• Design and development of fault-tolerant smart power devices for power management/storage (DC-DC converter and inverter bridge), and for electrical motor drives
3.5.1 Work Undertaken
WP4 was delivered by three tasks.
Task 4.1 electronic architectures: subsystems for power conversion (STM, SIEMENS, CRF, USFD)
The aims of this task were to define the specification for the smart power subsystems and to define the appropriate physical architecture derived from mechatronic expertise, to ensure highly integrated, energy efficient power conversion taking in account both the constraints of novel motor solutions, and requirements of specific EV application control and safety strategies.
Several circuit topologies were analysed to define adequate parameters to meet the specification of two applications (smart power drive and power management) whilst satisfying the requirements on safety, performance, system costs, and at same time, to take advantage of energy recovery from motor on braking. Safety and communication requirements were investigated that determined specifications for flexible and fail-safe sub-systems.
Task 4.2 Smart power drive: (STM, USFD, SIEMENS)
Based on the initial optimization of PM traction machines established in WP3, design specifications/ constraints outlined in WP1 and the embedded modular architecture defined in Task 4.1 this task identified the required components (powers, driver, micro) for the smart power subsystem, and produced a prototype comprising the inverter bridges and dedicated controller with embedded fail-safe concepts, able to support high efficiencies over the wide torque/speed range demanded.
Task 4.3 Power management/storage system : DC-DC converter and inverter bridge integration (STM,
SIEMENS, CRF, USFD)
Based on the analysis developed in WP1, the findings of WP3 and the solutions adopted in T4.1 this task identified the required component, system integration and control strategies to achieve high efficiency bidirectional coupling between the drive and the accumulator pack.
3.5.2 Scientific and Technical Results
Smart Power Subsystems
The major focus here centred on the smart power subsystems with the aim to define the appropriate architecture derived from mechatronic expertise, able to ensure a highly integrated, energy efficient power conversion taking in account both the constraints of novel motor solutions, and requirements of specific EV application and control strategies. The definition of the power sub module could not be disconnected from both technologies in order to reduce the parasitic switching energy effect and EMC noise, and from the techniques of attachment/soldering to optimize thermal exchange between substrate and device and allow a drastic reduction on switching commutation loss. The objective was to develop a dedicated power module and control solutions based upon the integration of several control strategies to provide an inverter bridge for Hi-Wi, with integrated control capabilities and a DC/DC power converter for efficient energy management based upon the voltage and power requirements determined by WP1 and WP3. An ad hoc inverter was designed using a prototype power module designed to meet the objectives of Hi-Wi, and assembled on the pilot line in Catania with new power devices in Si (IGBT 200 A single die) in a dedicated redesigned structure for the ST A3 power module. The choice of power semiconductors plays a key role in power conversion applications, the increased demand for high power density and assembled reliability become a key objective. This required the need and capability to combine several technologies regarding semiconductor production processes, packaging methodologies and system know how to create a power module with the appropriate characteristics of thermal performance, power density and robustness.
Figure 7 Front and rear view of smart power module from STM
3.5.3 Impact on other Work Packages
WP3 provided information that was used in the design and development of power requirements for WP5 and WP6.
3.6 WP 5: Motor Manufacturing
WP5 was the culmination from the outputs of WP1, 2, and 3, which led to the creation of the Hi-Wi motors for testing in WP6. The objectives of this work packages were
• To manufacture prototype motors with appropriate sensors and feedback devices.
• To perform tests and evaluation
• To deliver a complete motor unit for integration into the power train unit
3.6 WP 5: Motor Manufacturing
WP5 was the culmination from the outputs of WP1, 2, and 3, which led to the creation of the Hi-Wi motors for testing in WP6. The objectives of this work package were
• To manufacture prototype motors with appropriate sensors and feedback devices.
• To perform tests and evaluation
• To deliver complete motor units for integration into the power train
3.6.1 Work Undertaken
Work in WP5 consisted of five tasks.
Task 5.1 Prototype motor manufacturing (SIEMENS, USFD, UCAM, CRF, IPM)
Prototype motors were manufactured using a modular design approach. One type was manufactured using conventional hard magnetic materials to demonstrate the new topology, whilst a second type evaluated the techno-economic benefits of the low rare-earth magnets developed in WP2. Trial tooling and jigs were designed and constructed to explore the rotor manufacturing process required by the new magnetic materials. The iron core and the windings of the electrical machines were manufactured using the best and most cost effective material supply chain. Volume manufacture experience supplied by SIEMENS ensured that particular care was taken regarding the detailed mechanical design of the parts (magnets, core, windings) such that easy and low cost manufacturing could be achieved whilst preserving very high power/torque densities.
Task 5.2 Mechanical integration (USFD, CRF)
Motor enclosures were designed and manufactured. The preferred option was air cooling, although a
detailed trade-off study was performed to compare this and other options with respect to reliability, cost and ease of manufacturing. The rotor assembly units were integrated into the mechanical enclosure and the assembly along with integrated feedback devices for temperature, position and speed.
Task 5.3 Preliminary test (SIEMENS, USFD, CRF)
Comprehensive testing of the prototype machines and drives using prototype inverters under representative operating conditions was undertaken on a dynamometer available within the consortium. The results were used to validate the models, control strategies and theoretical performance predictions, and to assess the techno-economical benefit of the developed traction drive technology and hard magnetic material. Mechanical (vibration, over-speed) tests were also performed on the test bench. The further steps necessary for commercialisation of the developed motor drive technology were identified.
Task 5.4 Motor + power converter assembling (USFD, CRF, STM, SIEMENS)
- The outcome of Tasks 5.1 5.2 and 5.3 were integrated into a complete drive unit ready for testing in WP6.
Electric motor design report
This report summarised the electromagnetic and mechanical designs of the front and rear motors for the Hi-Wi traction system. Finite element analysis (FE) predicted the performance of the motors over the various driving cycles and at typical operation points. Demagnetisation risk, thermal limits and mechanical stress under extreme operating conditions were assessed, and the mechanical drawings for the key components and enclosures were presented including motor parameters for subsequent modeling and control.
With the objective to achieve high energy efficiency over a wide torque-speed operating region, the Hi-Wi power train employed two different electrical machine technologies/topologies for traction. Torque distribution between the front and rear axles through dynamic apportioning enabled additional energy saving. The motor developed for the front axle employs an interior-mounted permanent magnet machine (IPM) with innovative fractional slot windings for its high torque and power density, and a permanent magnet assisted synchronous reluctance machine (PMA SynRM) with low high-speed loss was selected for the two rear motors. The designs for both types of motor were generated following systematic optimisation and performance evaluation.
Hi-Wi front motor
The machine topology of the front motor, an interior mounted permanent magnet machine with 18 stator slots and 8 rotor poles, is shown in Figure 8. The coil sides of the 3-phase windings were placed in the stator slots in superposition. The magnets were embedded in the rotor lamination in a V-shape to enhance torque production capability through the reluctance torque and to improve field weakening capability for high torque and wide operating speed range. The key merits of this novel machine topology were detailed in deliverables D3.2 and D3.4 of WP3. The efficiency map over the torque-speed operating envelope is shown in Figure 9 and the complete motor assembly is shown in Figures 10 and 11. Efficiencies from 94% to 97% can be achieved over a wide region with the torque up to 50 Nm, and speed up to 5000 rpm.
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Figure 9 Efficiency map of the Hi-Wi front motor
Figure 10 Complete Hi-Wi front motor design
Figure 11 Hi-Wi Front motor
Hi-Wi Rear motor design
According to the comparative and optimisation studies performed in WP3, the Permanent Magnet Assisted Synchronous Reluctance Motor (PMa-SynRM) appeared to be a highly suited topology for the rear motors of the Hi-Wi drive train. The presence of low-cost ferrite magnets in the rotor allows this topology to achieve a higher power factor and torque density compared to a purely synchronous reluctance machine (SynRM). The low remanence permanent magnets embedded in the rotor result in a relatively low torque density, when compared to conventional PM machines with rare earth magnets, but the outstanding field weakening capability of this topology can compensate on the power density. The low manufacturing cost as well as high reliability and fault-tolerance capability due to the weak embedded PMs (viz. ferrite or bonded NdFeB) were additional attractive features that favoured this choice for the rear motors of the Hi-Wi drive train. A 2-D cross section of the PMa-SynRM is illustrated in Figure 12.
The traction machine and combined system (machine & inverter) efficiency maps (EMAPs) along with the NEDC and Artemis representative points are depicted in Figures 13 and 14 respectively. As can be observed from the figures, the majority of both driving cycles’ representative operating points are located in the higher efficiency regions. The complete assembly of the rear traction machine is shown in Figures 15 and 16
Figure 13 Traction machine efficiency map with driving cycles’ representative points
Figure 14 System (machine & converter) efficiency map with driving cycles’ representative points
Figure 15 Complete assembly of Hi-Wi rear traction machine
Figure 16 Hi-Wi rear traction motor
Functional test report on motor units
In the Hi-Wi project SIEMENS performed comprehensive testing of three prototype machines (two rear motors and one front motor) under representative operating conditions. The front motor was tested with two different rotors. The first rotor of the front motor was equipped with conventional magnets. The second rotor used the new magnetic material developed in WP2. The tests were performed with a preliminary inverter on a test bench with a speed variable dynamometer, as shown in Figure 17.
Figure 17 Test stand for electrical machines
The tests confirmed that the real motor data fits well with the calculated data. The efficiency at continuous load was measured at 87 % for both Hi-Wi rear motors, whilst the HiiWi front motor efficiency at continuous load was measured at 91 % with the rotor using conventional magnets and 93 % when using the rotor with the new magnetic materials.
3.6.3 Impact on other Work Packages
WP5 has shown with great certainty that the work carried out in specifying the system in WP1, the development of the new low-level rare earth magnetic materials in WP2, the simulation and modelling in WP3, and the motor design and manufacturing in WP5 have demonstrated excellent results.
3.7 WP 6: Drive Integration, Electronic, Mechanical Coupling
WP6 brought together and built upon the outputs of WP1 to WP5 and had the following objectives
• Mechatronic module integration
• Enclosure, cooling system and cinematic coupling design and implementation
• System assembling, testing and validation
• Automotive qualification strategy against robustness requirements definition
3.7.1 Work Undertaken
The work in WP6 was delivered through 6 tasks
Task 6.1 Electronic power drive and motor integration strategy (CRF, STM, USFD, SIEMENS)
This task provided definition of an integration strategy for the power electronic drive designed and manufactured in WP4 and the electrical machine designed in WP3 and manufactured in WP5 in terms of overall reliability, accessibility for maintenance, electric and magnetic field emissions, cooling and power dissipation needs.
Task 6.2 Structural properties of the electrical machine analysis and assessment (CRF, UCAM, USFD)
The electrical motors were studied against mechanical specifications in terms of structural strength, vibrations and noise by means of CAD-CAE techniques. Configurations with conventional and novel materials were assessed against automotive requirements.
Task 6.3 Drive Package and Cooling system design and implementation (CRF, SIEMENS, USDF)
With the final goal to address a modular power train system composed of independent globally optimized accumulator-electronic drive-motor blocks, the cooling system for the accumulator pack unit, the electrical motor and power electronic unit were designed according to criteria defined in Task 6.1.
Task 6.4 System final assembling, test bench design and manufacturing. Test procedures (CRF, SIEMENS, STM)
The subsystems were to be assembled in a package having mechanical (flange) and electrical (connectors) interfaces easy to connect with the wheel, the central charger and the main sensing and management system unit of the powertrain system as a whole. A test bench for the functional dynamic evaluation of the single power-train block was designed and implemented. Proper test procedures were defined first to assess the system against the specification and the criteria defined in WP1 and secondarily to envision future full automotive qualification and compliance with regulatory issues. A test bench was designed and implemented.
Task 6.5 Testing and final debugging and assessment (CRF, SIEMENS, STM)
The final system debugging was performed, and a complete test plan was implemented according the test procedures defined in Task 6.4. The results of the testing were analysed and evaluated against the validation criteria.
Task 6.6 Robustness validation strategy planning and preliminary robustness validation by simulation (CRF)
A preliminary validation plan was prepared by means of simulation tools to identify parameters for the future implementation of a full automotive qualification against robustness validation guidelines.
3.7.2 Scientific and Technical Results
Power drive integration strategy
This objective was met through processes of theoretical design, CAD/CAE simulation, the construction and interconnection of some elements of the system where appropriate, the generation and embedding of software, the bench testing of physical prototypes and the examination of materials and structures to determine their suitability for automotive use
Drive package and cooling system
Different power train strategies were considered along with their drawbacks and advantages according to CRF studies The power train used in the vehicle of a related project (WIBEMOB) was also considered. The CAD data of the WIDEMOB power train was used as the base for the simulation of the air flow and the thermal consideration on the inverter and motor, according to the mission profiles presented in WP1. The Fiat 500 hybrid battery pack model was used to study the impact of incorporating a super capacitor on the lifetime of the batteries when the mission profiles developed in WP1 were applied. The matrix of simulations and studies provided a wide-ranging view of the potential performance of the Hi-Wi motor/inverter if it were to be incorporated into the WIBEMOB vehicle. The simulated integration of the WIDEMOB vehicle and the Hi-Wi system (front and rear inverters/motors) assessed the local heat exchange coefficients and fluid temperatures taken at a specified distances from the surface of the corresponding elements. The simulation was performed with StarCCM+ at the following speeds: 5-15-35-65-95-115-135 km/h. The 3D data for the simulation were those derived from the integration analysis of the WIDEMOB vehicle with the Hi-Wi inverters and motors. The skin temperatures of the electric motors and inverters were taken into account and imposed to 100 °C. Figure 18 shows a section across the resulting 3D model.
Figure 18 WIDEMOB vehicle with HI-WI inverter and motor integrated, simulated air speed around the vehicle and under the boot and bonnet at a speed of 5 km/h
Structural properties of magnetic material
The flexural strength and hardness of the Hi-Wi magnets were assessed and compared to the original substrate material, substrates which have undergone heat treatment without having been coated with dysprosium and manufacturer supplied data for the substrates. The untreated substrates and the Hi-Wi magnets did not show a significant variation in strength.
Drive unit assembly
The aim was to assemble the complete Hi-Wi e-drive, with electrical and mechanical interfaces. After a series of preliminary tests of each available component of the powertrain, a representative system was assembled on a customized test bench, in order to validate the system against the specification and the criteria defined WP1. The test bench arrangement was focused for efficiency verification of the powertrain over the three specific driving cycles
• Urban cycle;
• Extra-urban cycle;
• Up&Down Hill cycle.
In order to implement this dynamic test CRF developed specific devices for the installation, including the supply and the cooling of all the Hi-Wi powertrain. The output of the tests were a detailed efficiency map over the three different cycles and the average value was well matched with the predictions.
System Tests
Through test runs of the Hi-Wi e-drive it was possible to verify the performance and efficiency over specific working cycles. The defined cycles were divided into two different categories, the first one was linked to real usage of a pure electric vehicle (Urban, Extra-Urban and Up&Down Hill cycles) and the second was linked to the homologation environment (WLTC Class 2 and NEDC Cycles). The complete electric powertrain was able to run over all the defined working cycles without any thermal problems. Excellent average efficiencies were detected and confirmed by the on bench test over WLTC Class 2 and NEDC cycles.
3.7.3 Impact on other Work Packages
The goal was to confirm and validate the system against the specification and the criteria defined WP1. In addition, the tests link directly to other work packages that were responsible for the new magnetic materials WP2, validation of design and simulation outputs in WP3, and motor design and construction in WP5. The results from WP6 validated all of the Hi-Wi research outputs and mark the success of the overall programme.
Potential Impact:
4 The potential impact and main dissemination activities
4.1 Background
The top-level aim of the Hi-Wi project was to accelerate the deployment of electrical mobility by merging, at the European level, public and private resources to develop highly-efficient next-generation powertrain systems. Hi-Wi outputs have exploited breakthrough developments in nanotechnology, magnetic materials, motor topology, and smart systems integration.
Electrical vehicles for personal mobility will profoundly affect every walk of life, trigger significant changes in electricity distribution and the marketing of automobiles, and potentially bring major benefits for the economy, the environment, health, family and leisure.
Electric vehicles also promise to reduce vulnerability to trans-national fuel supply chains, but there is a danger of substituting this problem with new obstacles in the securing of Rare Earth Element magnetic materials, a concern that has been addressed by the more efficient motor design topologies and advanced materials research outputs from the Hi-Wi project.
The foregoing prospects for societal gain and greater energy/materials autonomy for the EU make it imperative to define, review and lay down the fundamental principles of electric drive trains - from the energy store to the traction wheels - with the utmost care.
The Hi-Wi team engaged with the high-level architecture of the powertrain as an immediate priority, for it is only in the context of a new and appropriate framework that the optimum direction can be determined for advances in materials, production processes, motor design and control systems.
For the first time in the history of mechanised mobility, technological advances, driven by electrification, electronics, advanced materials and software, have reached a level for full optimisation of the performance and efficiency of an integrated powertrain, across the full range of real-life driving conditions.
Electrical mobility is widely recognised as the route to save the primary energy consumed in transportation. Moreover, efficiency gains are generally acknowledged to minimize the use of natural resources, whether exhaustible or renewable. However, the real drive for the uptake of the electric car will be economics. Even a single 1% increase in powertrain efficiency will bring about a 1.3% reduction in the weight and cost of the battery pack. With a 20 kWh pack costing some €7,000 this saving amounts to €90, which is higher than the cost of the motor.
This example illustrates just one of the multiple knock-on impacts of improvements in powertrains. But without such basic economic advantages to push the adoption of electrification, none of the hugely beneficial environmental, societal and broader economy advantages can be realized.
The Hi-Wi objectives of delivering HIGHer efficiency across a WIDE operating region promises efficiency gains well beyond 1%, across a full range of driving conditions and with reduced dependence upon vulnerable supply chains were ambitious and yet were met with resounding success.
4.2 Impact on Electrical Machines
The FP7 Work Programme for electrical machines (GC.SST.2010-7-1) stated that, “The successful introduction of electric vehicles in the market requires the development of electric machines that are at the same time cheap and highly efficient (on a wide torque/speed range) with high power to weight and volume ratios. At the same time they should also be reliable and robust, in order to withstand the harsh environmental and usage conditions imposed by the automotive standards achieved with the internal combustion engines”. The topic advocated the development of electronic architectures, compact/miniaturised mechatronic modules and highly integrated, energy efficient power electronics technologies and subsystems for power conversion.
Exploring innovative topologies and concepts (including consideration of intrinsic fault tolerance or methods to cope with unavoidable faults) for the various types of applications (from in-wheel to stand-alone or engine-integrated ones), was a significant challenge. Hi-Wi addressed these challenges through Work Packages 1, 3, 5 and 6, which respectively delivered the overall architecture, novel motor topologies and their assembly processes, and schemes for in-vehicle integration. The motor topologies targeted a significant reduction of the reliance upon Rare Earth Element magnetic materials, avoiding potential cost hikes and supply chain disruption. Researching high performance magnetic materials design and production, WP2 and WP3 investigated the synthesis of novel magnetic/composite as pre-formed bulk components, and modelled their properties and behaviour. The development of these materials have, as for the motor topologies, significantly reduced reliance upon Rare Earth Element magnetic materials, with savings in Dy content of 75-84% overall for the same coercivity, and a 5% improvement in remanence which offers improved motor torque.
Defining simplified, high efficiency cooling concepts was met by Hi-Wi through its twin objectives of optimally partitioning the motive power and gaining HIGH efficiency over WIDE operating conditions. This will allow future EU EVs to have superior operating performance over competing vehicles.
Developing advanced magnetic modelling tools through WP3 by the work of IPM (world leaders in this field) will greatly enhance EU competencies in this area by offering non-specialists the ability to design optimised magnetic systems
New automated manufacturing concepts developed in Work Packages 2, 5, and 6 , have delivered a blend of manufacturing process opportunities, ranging from disruptive and speculative through to incremental engineering development. These impacts will offer EU industries a distinct competitive advantage in delivering efficient manufacturing processes.
4.3 Hi-Wi Impact upon the Introduction of Electric Mobility
Electrified mobility is currently a top priority in the US, Japan, China, Korea and EU. It promises to introduce a radical industrial change in our society, as new technologies and infrastructure are put in place over the next two decades. The transition phase is now starting, with a growing awareness that the underlying technology to implement electrical mobility is reaching a sufficient level of maturity. There is now a push at many levels (global, EU, national, organisational) to refine and implement enabling technologies and systems so as to effect a platform for fundamental change to our road transport paradigms and to embrace the possibilities promised by the transition to electrical vehicles. The promises behind the move to electrical mobility are:
Reduction in oil consumption,
• “Well to wheels” energy efficiency is the key factor;
• The potential economic benefits are significant;
• In Europe 73% of all oil is consumed by transport. Road transportation accounts for over 85% of this
Improved safety of road transport,
• There are 5 lethal accidents every hour, and road accidents are the main cause of death in the under-45 age group, besides
• Electrification offers the opportunity to incorporate radical new safety paradigms with innovations in systems design and communications structures.
Reduction in emissions and noise produced by road transport,
• Environmental benefits, including mitigation of climate change risks;
• Public health benefits;
• According to the WHO, noxious gas emissions emitted by cars cause an even higher number of deaths that those caused by road fatalities. Electrical mobility eliminates noxious gas emissions in cities;
• electrification offers the opportunity to incorporate radical new safety paradigms with innovations in systems design and communications structures.
In the context of burgeoning vehicle electrification, the EU now has an opportunity to compete effectively in a global context. The strengths of EU innovators in embedded systems design, nanoelectronics and systems integration could be exploited further to be assured of a significant European stake in the massive market that is set to emerge in the coming decades. The Hi-Wi project has provided underpinning science, understanding and practical developments to exploit this opportunity.
Referring to the recent electrification roadmap released by the three EU platforms ERTRAC, EPoSS, SmartGrid, the impact of the electrical mobility compared with conventional transport can be usefully quantified in terms of energy and resource security, climate change, public health, freedom of mobility, and economic growth:
Primary energy savings Due to the EU’s growing dependency on primary energy sources this parameter is very likely the most motivating one. 73% of all oil in the EU (and about 30% of all primary energy) is consumed by the transport sector. Biofuels and natural gas are making an important contribution to fuel security, however only for a small fraction of the total needs.
To quantify the technological evolution that makes electrical mobility appealing we take as reference an ideal powertrain of a vehicle whose energy consumption depends only on mass, aerodynamic drag (frontal area and Cx) and the rolling resistance of the tyres. We suppose that for the New European Driving Cycle (NEDC) such a vehicle will consume 120 Wh/km. The amount of primary energy consumed by such vehicle depends on the chosen cycle and varies in relation to the typology of the powertrain and the need of energy for cooling or heating. Hi-Wi has made significant advances in these aspects of power train design and operational efficiency.
The peak efficiency of an electrical motor at defined power and torque values can reach 95%, compared to 45% for an internal combustions engine. In electrical motors this may drop to below 60% in extreme cases, but an electrical powertrain can be designed to be intrinsically less sensitive to the characteristics of the driving cycle. For instance, by using more than one motor the average efficiency can be kept at above 90% for a large range of delivered powers and torques. Hi-Wi has delivered motor efficiencies of some 93% using the new magnetic materials.
The overall combined efficiency of power switches, DC-DC and DC-AC inverters can reach 90% whilst that of motors and gears depends on the chosen driving cycle with typical values ranging from 80% for driving cycles requiring large excursions of power and torque to 86% for smoother cycles. In conclusion, from the battery to the wheel, the modern electrical powertrain can promise efficiencies in the range of 72%-77%. The outputs across all of the technology innovations in Hi-Wi have greatly in increased the performance of EV systems and as such could have a significant impact on the take-up of EV power trains in personal mobility applications.
Reducing Green House Gas Emissions Vehicle emissions contribute to the increasing concentration of gases that are leading to climate change. In order of significance, the principal greenhouse gases associated with road transport are carbon dioxide (CO2), and methane (CH4). In the EU the transport sector causes 26% of all GHG emissions due to human activities. Although these are only 4% of the total GHG emissions, they accumulate in the atmosphere as the ecosystem is unable to react-compensate at the same rate of change as human activities have brought about in the last one hundred years.
The transport sector is the fastest growing source of greenhouse gases, and of the total from transport, over 85% are due to CO2 emissions from road vehicles. Therefore, they are considered a major sector to attack for a limitation of GHG emissions. Well-To-Wheel CO2 emissions for electric vehicles are some 60% of those resulting from comparable Internal Combustion vehicles. This mirrors the comparison for Well-To-Wheel energy consumption
Reducing noxious emissions (raising public health) Road transport causes emissions of nitrous oxide (N2O) and also remains the main source of many local emissions including benzene, 1,3-butadiene, carbon monoxide (CO), nitrogen oxides (NOx) and particulates (PMs).
Within urban areas, the percentage of contributions due to road transport is particularly high. There is a growing body of evidence to link vehicle pollutants to human ill health including the incidence of respiratory and cardio-pulmonary disease and lung cancer. In general, according to the World Health Organisation, emissions from car exhausts are responsible for more deaths than road accidents. EVs eliminate all the side effects due to the burning of hydro-carbon in conventional vehicles.
Global competitiveness The development of new architectures from the Systems Integration point of view is the aspect that more than any other will defend the competitiveness of EU companies against those of the USA and Asia.
The next generation of Electric vehicles offers the chance to implement a radical new concept for the control architecture based on distributed propulsion and purely electrical power supply and distribution. Based on this paradigm change, EU industry will be in a commanding position to lead the exploitation of innovative mobility solutions.
The impact of Hi-Wi will be seen in changed supply chains in the automotive industry, in new market entrances and value creation among the production lines.
The outputs of Hi-Wi will contribute to the development of a European standard reference technology platform for electric vehicle design, which contains architectures, models, methods, and tools for real time embedded system development, verification, validation and testing.
Supply chain security Electric vehicles promise to reduce vulnerability to trans-national fuel supply chains, but there is a danger to substitute this problem for new obstacles in the securing of Rare Earth Element magnetic materials. Hi-Wi has greatly reduced this vulnerability, addressed by the project’s more efficient motor design topologies and advanced materials research outputs.
Benefits through partnership The Hi-Wi project has grown the capabilities of its European partners, enhancing the quality and reliability of European smart integrated systems, architectures and platforms for the design of next generation electrical and hybrid vehicles. The project will have a direct impact on reducing the design cycles, the development costs and time to market of electric vehicles. This will also include the development of accelerated test methods and enhanced qualification strategies. The industrial partners will see these benefits through elevations in market position, and these successes will pass down the supply chain. Research partners will gain valuable expertise to aid further the industry.
4.4 Dissemination Activities and Exploitation of Results
During the course of the Hi-Wi project, multi-stranded dissemination activities took place aimed at promoting its research and at reaching the widest and varied audience possible. The dissemination plan (Task 11.1) was written by UCAM, with contributions from all partners, and sent to the project coordinator in March 2011. The plan defined the audience for dissemination, and some key dissemination tools and dissemination activities:
• Management meetings, bilateral meetings and review meetings
• Shared workspace
• Contact with the supply chain regarding project requirements
• Web site
• News bulletins, Review publication and Journal / Conference papers
• Conferences, EU Technology Platform and brokerage events, Industry groups
• Use of deliverables, particularly those based on industry insight, to inform researchers and students/trainees
All individual presentations are stored in the restricted shared workspace, and thus accessible for all project partners to use as appropriate. Standard templates were used when creating the presentations to make sure that a unified identity was preserved to maximise recognition and impact.
4.4.1 Dissemination material and tools
1. Official project website
The official Hi-Wi project website has been available since month 2 of the project at www.Hi-Wi.eu.org. The objective of this website is to provide information regarding the project addressed to the public. It contains: a brief introduction to the project’s aims, objectives and Work Package activities; A review of the project’s publications; Robust and expansive statements regarding Applications and Licensing The website was created and updated by UCAM (with support of all participants), and will be maintained and hosted by UCAM after May 2014.
2. Logo, PPT and deliverable templates
A logo was created to maintain the corporate identity of the Hi-Wi project. Templates for Power Point presentations and deliverables were designed to ensure a united presentation to those external to the project.
3. Avenues for Knowledge flow and dissemination
The avenues that were indentified were:
• Sharing of knowledge between partners and diffusion throughout their organisations
• Engagement with the commercial supply chain and user organisations
• Engagement with the research base
• Informing of strategists within industry and the research base
• Skills delivery through the provision of informative reference/teaching/training materials
During the project the partners learned much from each other, and in particular some of the deliverables from industry greatly informed the university researchers, to an extent where some deliverables could become teaching aids.
4. Knowledge channels
Six categories for dissemination were chosen, Figure.19 being distinct from the task-orientation of the Work Packages. This approach allowed a more “generic” targeting of the project outcomes, which, as it transpired during the project, promised application wider than just the Electric Vehicle domain.
Figure 19 Knowledge channels
5. News bulletins
A simple 2-page format enabled quick customisation for distribution at conferences and industry events.
6. Review publication
A comprehensive document aimed specifically at potential users of the project outcomes
7. Journal and conference papers
Extensive publications, especially towards the conclusion of the project when outcomes could be described
8. Conferences, EU Technology Platform and brokerage events, Industry groups
In addition to the research conferences recorded, project personnel attended and contributed to a number of industry events.
List of Websites:
5 Website and Contact
5.1 Website
The Hii-Wii website can be found at the following link:
http://www.hiwi-eu.org/
1 Executive Summary
Presently, drives for Fully Electric Vehicles and Hybrid Electric Vehicles develop their highest efficiency of around 93–95% within a speed range of usually 1/4 to 1/3 of the maximum, and at an ideal torque, whereas in real-life driving cycles the motor operates at a wider range of speeds and at partial load, resulting in much lower efficiency. The Hi-Wi acronym is derived from the project target of developing an electric architecture with both a higher efficiency and a wider application range, so that the vehicle can operate efficiently in all operating conditions
The Hi-Wi project has developed advanced electric traction motors for electric vehicles through the application of holistic design across magnetic, thermal, mechanical and control electronics/algorithms in line with real-life use rather than a single-point “rating”. This was achieved through the provision of advanced modelling and simulation tools, for both materials, and electrical systems under various driving cycles relevant to the EU consumer.
The anticipated growth of the electric and hybrid vehicle market means that the subsequent demand for permanent magnets that are central to this technology is certain to grow dramatically. Considering the resource distribution of rare-earth metals, European car manufactures have to face the problem of restrictive and vulnerable supply chains for rare earth metals, since most reserves are outside Europe and more than 95% of the production is in China or in the hands of Chinese companies. This has already led to a sharp increase in price for rare-earth metals (such as Neodymium (Nd), Dysprosium (Dy) and Terbium (Tb)) because they are essential additives to produce high energy-product magnets. A significant problem for the EU is that it holds no rare earth reserves. There was therefore a pressing need to develop advanced motors for FEV applications that relied less on rare earth elements, but could still remain competitive with the growing competition from China and elsewhere. Hi-Wi coupled its novel design approach to breakthroughs in materials and manufacturing, winning size, weight, logistical and cost savings through the use of nano-scale modelling techniques which led to a better understanding of the means by which rare earth materials could be applied leading to greater levels of resource efficiency. Research completed by Hi Wi has led to magnetic materials advances, that have created superior magnetic field strengths with reduced reliance upon rare earth elements, reducing exposure to their economically-vulnerable strategic supply chains. Magnet production was achieved through the adoption of nano-scale magnetic material usage and a step change in the manufacturing processes for magnetic materials with savings of some 81-84% in Dy content, and an overall saving of 40% in rare earth consumption for FEV powertrains.
The new technologies developed in the Hi-Wi project will secure important improvements over current motor and vehicle architectures, such as delivering higher energy efficiency (i.e. more power with less battery consumption) over a wider spectrum of rotating speeds, and decreasing resource dependency on rare earth materials. The motor architectures and the innovative materials developed in the Hi-Wi project have the potential to reach way beyond the electronic vehicle market. Permanent magnet machines have a paramount importance in many other fields, such the as core of the electric m used in all wind generators, industrial fans, blowers and pumps, machine tools, household appliances, power tools, and disk drives.
Project Context and Objectives:
2 Project Context and Objectives
Electrified mobility is currently a top priority in the US, Japan, China, Korea and EU. It promises to introduce a radical industrial change in our society, as new technologies and infrastructure are put in place over the next two decades. The transition phase is now starting, with a growing awareness that the underlying technology to implement electrical mobility is reaching a sufficient level of maturity. There is now a push at many levels (global, EU, national, organisational) to refine and implement enabling technologies and systems so as to effect a platform for fundamental change to our road transport paradigms and to embrace the possibilities promised by the transition to electrical vehicles. In the context of burgeoning vehicle electrification, the EU now has an opportunity to compete effectively in a global context. The strengths of EU innovators in embedded systems design, nanoelectronics and systems integration must be urgently exploited to be assured of a significant European stake in the massive market that is set to emerge in the coming decades. The outcomes of the Hi-Wi project enhance the EU’s capability to exploit this opportunity. The route towards fully electric vehicles will be more and more motivated by considerations of resource efficiency both in terms of material use and energy savings, in addition to the development of city regulations. EU policy and regulation are further driving forces towards better environmental standards for personal and business transport. Energy efficient vehicles have a major role to play improving environmental standards and the electromobility is a major enabler of energy efficiency strategies.
Lighter and smaller sized cars could be designed with an ideal powertrain requiring less than 60Wh/km and a reduced overall battery pack. The path toward low cost electrification is a complex one requiring, as in Hi-Wi, new approaches to vehicle design as well as a shift to radical improvements in powertrains. Hi-Wi outputs will contribute to the development of a European standard reference technology platform for electric vehicle design, which contains architectures, models, methods, and tools for real time embedded system development, verification, validation and testing. As described in the DOW, the three-year HI-WI project had the following objectives:
• The prototyping and demonstration of innovative topologies and concepts for FEV/HEV powertrain platforms, including in-wheel and engine-integration examples, with nominal power in the range of 3-6 kW and showing high efficiencies over the wide torque/speed range demanded by real-use driving cycles.
• Innovative approaches to the holistic design and modelling of rotating magnetic machines tailored specifically to the in-use conditions of FEV and HEV drive cycles.
• Micro- and nano-scale materials advances to create superior field strengths with reduced reliance upon rare earth elements and their economically-vulnerable strategic supply chains
• Micro- and nano-scale manufacturing advances to create permanent magnets and integrated assemblies having ideal geometries, reduced size and weight, and improved mechanical, magnetic, and thermal properties
• The development of advanced magnetic modelling tools and a multi-physics modelling environment tailored towards the requirements of EV powertrain applications
• The development of safety-first fault-tolerant adaptive electronic controllers for efficient bidirectional coupling between the drive and the accumulator pack
• Guidelines, standards, IPR and experience upon which to build a world-leading EU position in the economic mass manufacture of motors to exploit the global uptake of FEV and HEV mobility
Hi-Wi was organised as 6 technical work packages with two demonstrator streams. The Hi-Wi project brought together a particularly able mix of global companies, research institutions and SMEs to form a high impact research activity with deep experience in new enabling technologies for the production of powertrain systems. To deliver its objectives, the Hi-Wi project embraced the following topics:
• Embedded control systems architectures for electric vehicle and further domains based on distributed propulsion and distributed energy networks.
• Electrical power distribution architectures including related functional units.
• Information system network architectures.
• Sub systems functional design, and properties allowing reusability of software.
• Embedded systems, electronics, and software for functional module design and integration.
• Electric vehicle architecture definitions and optimization.
• Electric vehicle networks design and optimisation.
• Electric vehicle multi-domain analysis.
• Software and mechatronics design.
• Electric vehicle distribution systems design and manufacturing.
• Documentation and diagnostics.
• A forum to evaluate breakthrough materials and processes in the context of in-depth automotive applications expertise.
Intensive interaction between Hi-Wi partners was an essential ingredient in meeting Hi-Wi objectives. Breakthrough ideas in drive topology and materials synthesis generated by the university research base at Sheffield and Cambridge were tempered and informed by the global powertrain players Fiat, Siemens and STMicrolectronics. Accordingly, these global powertrain players have been offered a breadth of innovation, ranging from well-characterised engineering developments through to more speculative materials synthesis, from which they selected an optimum blend as the project progressed. This ability to choose and steer results to an appropriate Technology Readiness Level was essential to mitigate the risks of technology adoption. Agile SME capabilities in advanced modelling and simulation, at IPM and CEDRAT, brought a level of confidence to the adoption of the new ideas, condensing the normal timescales for optimising the new technologies to be implemented, yet providing the level of confidence demanded by the traditionally conservative global players. The success of developing and delivering technologies includes risks that are normally present in any R&D project involving the full-scale design and build of new technical systems within tight time-frames. The HI-WI programme was specifically constructed to have a “portfolio” of work balancing the high risk of speculative research against the more predictable progress of engineering development.
Project Results:
3 Main Scientific and Technical Results
3.1 Overview
At present, motors for FEV (Fully Electric Vehicle) and HEV (Hybrid Electric Vehicle) applications develop their highest efficiency of around 93~95% within a speed range of typically 1/4 to 1/3 of the maximum rotating speed, and at an ideal torque, whereas in real usage - in the majority of driving cycles - the motor operates at a wider range of speeds and at partial load (low torque) resulting in much lower efficiency. Hi-Wi addressed these issues by developing a novel powertrain approach to enable high efficiencies over a wide operating range.
There are restrictive and vulnerable supply chains for the rare earth element (REE) materials required to manufacture high magnetic strength components. Hi-Wi addressed this problem by developing new magnetic materials with reduced rare earth content.
To optimise powertrain design for Hi-Wi performance, the development of advanced magnetic modelling tools and a multi-physics modelling environment tailored towards the requirements of EV powertrain applications are required. Hi-Wi developed new modelling and simulation tools for power systems and magnetic materials.
3.2 WP 1: System Partitioning and Specification
The objectives of this work package were
• Partitioning of the electrical drive train and preliminary functional specification for the defined subsystems
• Detailed specification and related constraints (mechanical, thermal, electrical) of the drive train subsystems against the overall powertrain/vehicle target performances
• Study of the influence of various electrical machine architectures and electronic drive stages on the overall system performances, and on the efficiency, size and cost requirements.
• Definition of guidelines and design strategies to address high efficiency over a wide range of electric powertrain operations
• Definition of a strategy to apply the project developments on a test-bench and on a demonstrator vehicle
3.2.1 Work Undertaken
WP1 was central to the Hi-Wi project, as it established the design guidelines for achieving high efficiency over a wide torque/speed range based on a holistic examination of the energy distribution of the envisaged Hi-Wi power train. The work package was divided into 6 tasks:
Task 1.1 Overall Drive-train specifications and constraints (CRF, SIEMENS, USFD, STM)
The drive train architecture was analysed by means of software modelling tools against OEM requirements for Full Electric Vehicle lower-end classes A and Sub-A, (also called “micro car”) which have relatively low overall rated power.
Task 1.2 Wide-efficiency powertrain design guidelines definition. Trade-off studies and integration strategy (CRF, USFD, CEDRAT)
This Task established an integration strategy between the various components of the power train unit using a design framework that was established to address the design of a drive train having overall high efficiency over a breadth of real-use conditions.
Task 1.3 Power conversion and distribution subsystem specification (STM, USFD, CEDRAT)
The requirements for the power converter were defined in terms of DC-Link voltage (outcome of Task 1.2) max power (Outcome of Task 1.1).
Task 1.4 Electric motor subsystem specification (USFD, CEDRAT, SIEMENS)
The traction motor was specified against the rated and peak power, and torque (outcome of Task 1.1) and the winding voltage (Task 1.2) with particular care being applied to the definition of guidelines for the modularity of the electrical machine to make it suitable for the widest possible application range.
Task 1.5 Automotive interface specification (CRF, SIEMENS, STM)
Guidelines for electrical machine, gear and inverter integration were detailed for further analysis and the development of a powertrain system, composed of independent globally optimized accumulator-electronic drive-motor blocks. Mission profiles for urban/extra urban and up/down hill cycles were derived from statistical analysis upon real-world data acquired on selected routes, in addition to the development of a methodology to compare different mission profiles.
Task 1.6 Magnetic material properties specification and electric motor design guidelines definition; Verification & Validation strategy definition (CRF, UCAM, USFD, IPM)
UCAM worked with USFD to specify the required dimensions for magnets to be used in the new USFD motor designs and agreed on a target of 20 kOe for the coercivity of the new magnetic material to be developed in WP2. After its manufacture, the new reduced rare earth magnetic material was assessed using a permeameter in order to characterize magnetic behaviour over the temperature range of interest. The coercivity recorded at room temperature was 19.6 kOe. This met the requirements of USFD. The effect of the new magnetic materials on motor performance was explored through simulations carried out at USFD.
3.2.2 Scientific and Technical Results
Specification for the drive-train and Integration Strategy
The main data for the preliminary specifications of the traction electric motors were defined through close consideration of the constraints and requirements of the target vehicle. Following the exploration of possible transmission solutions, the powertrain architecture was established as one ‘central’ e-drive for the front axle and two ‘distributed’ e-drives to the wheels for the rear axle. In addition, overall guidelines for the traction e-drive integration were developed, including application requirements (environmental conditions, electromagnetic compatibility (EMC), expected operating life and protective measures) for an effective usage of the e-drive components of the powertrain.
Inverter and Motor Specifications
The design specifications of the motors and power converters based on the chosen vehicle power train architectures were based on two defined driving cycles (NEDC and Artemis Urban) and the requirements for acceleration and hill climbing. The effects of gear ratio and cooling conditions on motor sizes were also considered and the total energy consumptions over the two driving cycles were quantified. This work provided the basis for sizing the inverters and the battery for a given range requirement.
System partitioning and specification
This provided the framework for the Hi-Wi project, it established the design guidelines for achieving high efficiency over a wide torque/speed range based on the analysis of the energy distribution of the Hi-Wi vehicle power train. The work showed that the energy consumption of a traction motor can be represented by 12 discrete points, over which the design optimisation for minimum energy loss can be performed effectively and efficiently. This was shown to dramatically reduce the computation time required for the optimisation process. The work also demonstrated that ~73% of energy over the NEDC is consumed in high speed and low torque regions and it was therefore essential that the motor design should endeavor to match the high efficiency region of the traction motor to the high energy consumption points. Trade-off studies on the power train gear ratios were also developed, indicating that:
• Increasing the gear ratio from 4 to 7 reduces motor weight, size and cost by ~40%, but does not compromise the motor efficiency
• As gear ratio increases from 4 to 7, the transmission efficiency decreases, resulting in an overall reduction in efficiency by ~3% over the NEDC cycle
• Reduction of motor costs through using a 7:1 gear ratio may not offset the increase in battery cost for the same range requirement
• Gear ratio has a negligible influence on inverter VA rating, cost and efficiency
The work confirmed that the optimal design and efficiency of traction motors are dependent on a driving cycle. For the permanent magnet machines, since its high efficiency region is relatively wider than other machine technologies, this dependency is less significant. In general, to achieve high efficiency in the NEDC, the motor would have to be optimised to have high efficiency in low torque and high speeds. In contrast, high efficiency operation over the AUDC requires high efficiency in high torque and low speeds. By exploiting the distributed driving architecture of the Hi-Wi power train, figure.1 the best results would be obtained by optimising the front motor against the NEDC and the rear motors against the AUDC, thus, maximising the High and Wide efficiency operating range. The findings of this study were seminal for the subsequent design optimisation of the complete HIWI power train.
Validation and Verification
The standard driving cycles normally used only approximate the real scenarios that cars face over their service and usually fail to take into account different driving styles. Accordingly, the Hi-Wi project broke new ground by generating new mission profiles, devised through statistical analysis of real-world data collected over various scenarios with different driving style and traffic conditions. Three different scenarios were taken into account, they were called Urban, Extra Urban and Up Down Hill (figure.2). The car used was a FIAT 500 Hybrid. Mission profiles were defined from real data acquisition studies in order to develop test conditions for the new Hi-Wi motors.
Figure 2 Up Down hill driving cycles use in the validation trials
3.2.3 Impact on other Work Packages
WP1 was of great importance in that it defined the basis on which all technical specifications of the Hi-Wi project were developed including:- Specification for the drive-train; Design guidelines definition; Integration strategy; Inverter specifications; Guidelines for modularity of the electrical machine; Tractor motor specifications; Guidelines for integration of the power train; Mission profile definition from real data acquisition; Guide line for route selection; Methodology of comparison of different mission profiles; Specification and assessment of the new reduced rare earth magnetic materials; and simulation of the new rare earth magnetic material on motor performance.
3.3 WP 2: Magnetic Material and Manufacturing Process Innovation
Delivering significant reductions in rare earth element usage, whilst producing magnetic materials with the required levels of magnetic performance for FEV applications, was one of the greatest challenges of the Hi-Wi project. Accordingly, WP2 was not only ambitious but was also the work package with the highest risk factor. Its objectives were:
• To design & manufacture a laboratory based laser assisted supersonic powder deposition apparatus for the production of full density magnetic materials with geometrical control for the production of net shape magnetic components with reduced rare earth content
• To characterise the magnetic characteristics of laser annealed magnetic materials
• To establish a novel production route for nano crystalline rare earth magnetic materials utilising high speed laser annealing of ribbon or supersonic powder deposits.
• To fully characterise the new production route through a comprehensive parametric study of production variables for each magnetic material employed.
• To produce prototype high performance permanent magnets, with lower levels of rare earth consumption for application in a demonstrator Hi-Wi motor.
3.3.1 Work Undertaken
WP2 was divided into 6 tasks:
Task 2.1 Novel process route for the control of nanostructure in thin magnetic films. (UCAM)
Laser based annealing of iron rich NeFeB material was developed in order to produce a nano-exchange coupling effect that could allow local control of nanoscale grain structure leading to a magnetic material with high coercivity and reduced rare earth content.
Task 2.2 Characterisation of annealed films (UCAM,USFD, IPM)
The thin film magnetic materials produced in Task 2.1 underwent structural analysis using TEM, SEM and XRD to characterise their nanoscale features. Their magnetic properties were determined by hysteresis measurements and data generated here was fed into the magnetic simulation models developed by IPM.
Task 2.3 Production route for amorphous rare earth magnetic powders. (UCAM, IPM)
Spin casting of iron-rich liquid NeFeB droplets was used to produce amorphous powder flakes suitable for application in the magnetic deposition trials of Task 2.4. Structural characterisation of the resultant powders was undertaken using TEM, SEM and XRD analysis.
Task 2.4 Local in situ deposition of magnetic materials (UCAM, USFD, IPM, CRF)
This task developed an experimental deposition apparatus for magnetic powder feedstock produced in Task 2.3 with subsequent laser processing of the magnetic deposit to refine its magnetic properties.
Task 2.5 Characterisation of the deposition process for magnetic powders (UCAM, CRF, SIEMENS)
This task explored the optimum process conditions for depositing magnet structures on a range of substrate materials and geometries as defined by the requirements of WP3. These bulk magnetic samples were analysed for rare earth composition and magnetic characteristics.
Task 2.6 Magnet Production (UCAM, CRF, SIEMENS)
During the final 8 months of the project the materials and production system developed in Task 2.3 and Task 2.4 were employed in the creation of a number of test magnets as defined by the requirements of WP3 and used in demonstrator drive 2, a specially-built front motor for the Hi-Wi drive train. Particular emphasis was placed on the production of magnetic materials with reduced rare earth consumption without loss of magnetic properties.
3.3.2 Scientific and Technical Results
Production route for exchange coupled magnets
The key reason for this work was the drive to reduce the amount of rare earth material which is required to make the magnets in permanent magnet machines for use in Hi-Wi automotive traction systems. Improving the magnetic properties of the material and reducing the volume fraction of rare earth elements used was realised through the use of exchange coupled field techniques. Work outputs here identified a process route for the production of nano-structured magnetic materials. The primary work carried out an extensive study of the production of nano-structured and nano-composite rare earth magnet materials and the potential process routes to produce bulk magnets in quantities suitable for the creation of magnetic components for Hi-Wi motor designs.
Creation of optimised magnetic properties
Melt spun ribbons of amorphous NdFeB material were used in studies of laser annealing in order to assess conditions required for successful development of exchange coupled effects. The depth over which annealing could achieve the required nanostructures was determined through a range of experimental assessments. A series of samples of amorphous ribbon were annealed at differing powers and specific exposure levels while the thermal histories they experienced were recorded. The demagnetisation curves of the resulting samples were measured using a vibrating sample magnetometer and a selection of samples were examined using transmission electron microscopy in order to gain a better understanding of the nanostructures produced, as shown in Figure 4. Following this, the annealing process was tested and validated with a NeFeB composition with iron enrichment in order to develop an exchange-coupled magnetic structure suitable for application in Hi-Wi motors.
Production Route for Magnetic Powder
Gas atomisation was identified as the best route for amorphous powder production due to the need for spherical powders that were necessary for the deposition process employed. Magnequench Ltd, UK, provided modified gas atomised powders, 30% of which were sized sufficiently to meet the critical cooling conditions necessary for forming amorphous powder. This powder fraction was confirmed as amorphous through the use of x-ray diffraction techniques (XRD).
Magnetic Properties: Laser annealing of in-situ depositions
The proposed process route for the deposition and annealing of amorphous NdFeB powder was established early in the project. Apparatus for the laser annealing of wide areas of amorphous material was designed, constructed, characterised and demonstrated. This equipment allowed the relationship between thermal history and magnetic behaviour to be established more accurately than the early tests in D2.1 and D2.2. Magnetic performance was optimised by repeated pulses (up to 20) which raised the temperature of the material to 800 °C. Material annealed by repeated pulses showed increased coercivity relative to both single pulsed and furnace annealed material. The experimentally determined thermal history required for annealing was used alongside a model of the thermal history of a laser annealed amorphous layer to determine the appropriate deposition strategy for the laser annealing of successively deposited amorphous layers of Iron rich NdFeB in order to generate a bulk nanocomposite magnet. Novel deposition of NdFeB proved to be extremely difficult, despite many attempts being made, the majority of the early trials were unsuccessful. A modified deposition process was then employed with much greater levels of success. The magnetic performance of the new deposits suggested that the NdFeB structure was undamaged by the deposition process. The electrical properties of the metallic binder materials limited the potential application of this approach. These issues were addressed in an extended set of trials in order to address the very challenging issue of rare earth element reduction.
Magnet Production Route
The consolidation of amorphous precursors to allow the production of bulk nano composite magnets via the rapid laser annealing of successive layers of material proved to be unsuccessful. Accordingly, an alternative route to the production of bulk high performance magnets with reduced rare earth content was identified. This route opted for reducing the amount of Dy required. Dy is used in rare earth magnets to provide elevated Curie temperatures, a material characteristic essential in automotive traction applications when motors are driven with high loads and low speeds. Moreover, mimimising Dy content is desirable due to the fact that the cost of Dy is significantly higher than Nd and its supply is also relatively insecure. Because of this, the small additions of Dy present in magnets which need to operate at up to 150 °C can cost the same amount as the much larger fraction of Nd present in the magnet. The work package demonstrated the deposition of a controlled amount of Dy on to the surface of NdFeB magnets with very low levels of Dy the bulk material. By diffusing traces of Dy into the thin surface layer of sintered magnets by vacuum heating, a functionally graded magnetic structure was produced. Subsequent tests revealed significant improvements in their coercivity levels and therefore their maximum operating temperature to the levels achieved through the addition of ~ 5 times more Dy via conventional magnet production processes. This was a major achievement, and resulted in record breaking low levels of Dy consumption.
Production of Hi-Wi Magnets
Reduced rare earth content magnets were delivered to the University of Sheffield for use in the Hi-Wi front motor. The NdFeB based magnets used in the Hi-Wi motor were produced via the production route developed in Task 2.5. This resulted in magnets with an 84% reduction in Dy content when compared with conventionally produced material of comparable coercivity while at the same time giving an increase in remenance relative to conventional material (allowing for improved operating efficiency under high torque operating conditions).
3.3.3 Impact on other Work Packages
WP2 was of great importance to the Hi-Wi project in that it defined the basis on which new Hi-Wi motors could be developed in WP5 with significant savings in Dy consumption (84%) , and an overall reduction of rare earth consumption (Nd + Dy) by over 40%. It also provided essential material data for the development of magnetic simulations in WP3, and led to the validation of WP3 simulation outputs through the testing of Hi-Wi motor performance in WP6. Overall, the outputs of WP2 are far reaching with significant advances in European magnetic materials knowledge and application potential far wider than those originally envisaged in the Hi-Wi project.
3.4 WP 3: Powertrain Design and Simulation
The objectives of this work package were
• To establish multi-physics based modelling techniques for EV power trains.
• To develop multi-scale modelling tools for design and optimization of high-performance nanocomposite permanent magnets
• To develop computationally efficient algorithms and tools for system design optimisation of EV power train components with due account of multi-physics interaction.
• To perform comparative studies of electrical machine technologies (such as permanent magnet, induction and switched reluctance machines) for EV traction applications in view of anticipated price increase of rare earth permanent magnet materials.
• To develop high power/torque density and low cost brushless permanent magnet motors with high efficiency over a wide torque-speed range for EV traction application.
• To perform design optimisation of developed machine topology/technology using current state-of-the art and newly developed permanent magnet materials.
3.4.1 Work Undertaken
WP3 pervaded throughout the Hi-Wi project, as it established multi-physics modeling techniques for most elements of the power train including, magnetic materials, EV power train components, motor designs, and design optimization of machine topology. WP3 was divided into 6 tasks:
Task 3.1 Modeling of electric traction drives (USFD, CEDRAT, STM, CRF, SIEMENS)
This task provided the underlying definitions and strategy for the design and simulation of the electrical, electronic, thermal and mechanical dynamics of electrical power trains for EV propulsion, together with the defining of design methodology, tool integration and data flow control. Electrical power train component models included the e-motor, power electronics inverter, DC-DC converter, battery, and on-board vehicle power network, etc., with different levels of fidelity and abstraction, all of which were gathered and developed drawing from existing knowledge and expertise within the consortium members.
Task 3.2 Methodology and computer tools for magnetic material design and optimisation (IPM)
The development of methodology and computer tools for multi-scale modeling, design, and optimization of magnetic, mechanical, and thermal properties of nanopowder-based magnetic composites was carried out in this Task. An effective combination of first-principles, micromagnetic, microstructural calculations, and advanced numerical techniques was used to allow realistic simulations of modern magnetic composite materials with a physically complete formalism, enabling accurate predictions of their magnetic properties.
Task 3.3 Methodology and tools for system design optimisation (CEDRAT, USFD, IPM)
Based on the component and system models established in Task 3.1 and design specifications/ constraints outlined in WP1, Task 1.1 appropriate optimisation techniques, such as sequential dynamic programming, genetic algorithm and particle swarm, etc., were evaluated and integrated with components and systems design/simulation tools, such as SPEED (a tool for theor electromagnetic design electrical machines), MOTORCAD (a thermal analysis tool for electro-mechanical systems), Portunus (a power electronics and circuit analysis/simulation tool), Matlab/Simulink (system and control simulation and design tool) and Flux2D/3D (a numerical tool for electromagnetic and thermal analysis), to form a multi-physics based analysis and design optimisation platform.
Task 3.4 Comparative studies and development of novel machine topologies/technology for EV traction (USFD, CEDRAT, SIEMENS)
The aim of this task was to determine the best machine topology/technology for distributed EV tractions via a comprehensive set of comparative studies and examination of novel machine topologies.
Task 3.5 Design optimisation of PM traction machines (USFD, SIEMENS, UCAM)
For the selected “best candidate” machine topologies, a framework for assessing their performance was established. In addition to conventional specification parameters for continuous operation, this encompassed advanced electromagnetic loss calculations (accounting for the influence of time and space harmonic mmfs and PWM effects) and transient thermal models to assist the design optimisation at the system level. By establishing an analytical framework that incorporates a fundamental and detailed understanding of the torque capability and the loss mechanisms and heat transfer of the candidate machine topologies, the scope for realising high efficiency operation, over a wide region, was investigated.
Task 3.6 Complete electric traction drive simulation (USFD, CEDRAT, IPM)
The 2D finite element analysis based electromagnetic models of the designs in Task 3.4 were integrated with circuit simulations of inverters and accumulators in order to study the overall effect of magnetic simulation, material nonlinearities and harmonic currents on the drive performance. The full electric drive chain (accumulator+converter(s)+motor+load) was simulated by coupled 2D electromagnetic analyses and circuit simulation. The merits and performance of the complete drive chain employing the developed machine technology with both conventional and new magnetic materials were comprehensively assessed and evaluated.
3.4.2 Scientific and Technical Results
Modeling, simulation and design methodology and tools for EV power trains
Modeling, simulation, design methodology and tools have been specifically developed for the Hi-Wi project. Three powertrain models with different levels of fidelity to suit different purpose of study have been established based on the target vehicle data and power train configuration. To investigate the fault behaviour of the distributed Hi-Wi powertrain, a representative model with three independent motor drive units linked together by the vehicle rigid body dynamics and tyre characteristics has also been developed. The model was further extended to cater for two wheel and four wheel distributed power train architectures. This provided an effective means for evaluation of the consequences of drive failures. The theoretical background of each model, and their utilities for targeted applications were demonstrated through representative simulation results. The tool developed for electromagnetic-thermal coupled field analysis was also applied in motor design. A computationally efficient design optimisation method was developed based on in-depth understanding of the energy consumption distribution of the vehicle over the reference NEDC driving cycle. This together with the FE based optimisation tool (Got-It) enabled the global optimization of the traction machine aimed at maximum energy efficiency over the driving cycle being performed.
Comparative studies of machine topologies and technologies for EV traction
The most promising candidate machines for the Hi-Wi project to achieve high efficiency over a wide operating range, were defined following a review of the current state-of-the-art electrical machine technologies and topologies for EV traction. Evaluation of the appropriateness of each machine topology was based on a defined set of figures of merit for selection. The need for cost reduction and for avoiding potential restrictions upon the supply of rare-earth magnets were also taken into account in the comparative study. New concepts, advantages and disadvantages associated with the recent advances in electrical machine research and development were assessed. Subsequently, qualitative and quantitative comparisons among a selected number of candidate machine technologies and topologies were undertaken. The performance of the candidate machine designs are summarised in Table 1.
Table 1
Methodology and computer tools for magnetic composite design & optimization
A model was developed by IPM, Figure 5, to study exchange-coupled magnetic systems (also known as exchange-spring magnets). The demagnetisation process of the model SmCo/Fe/SmCo trilayer was analyzed in the framework of a three-dimensional model based on the numerical integration of the Landau-Lifschitz-Gilbert equation using a SpinPM Micromagnetic Solver. The hysteresis loops obtained for such a trilayer with different geometric parameters allows one to optimise the layer thickneses in order to maximize the energy product. The model was validated through a comparison with the experimental data available in literature.
Development and design optimisation of electrical machines for Hi-Wi traction systems
It has was shown that by employing a dynamic torque apportioning strategy, the overall traction system efficiency with distributed power train configuration could be improved by using dissimilar machine technologies or topologies. In this way, to achieve high efficiency over a wide operating range, the motor or motors for one of the axles should have high efficiency, while the motors or motor for the other axle should exhibit low no-load loss or low idling loss. Based on this understanding, the newly developed fractional slot permanent magnet (PM) machine with low space harmonic content was selected for the front motor, and a permanent magnet assisted synchronous reluctance machine which does not use rare earth magnets was adopted for the two rear motors. Design optimisations against a number of representative driving cycles, such as NEDC, Artemis Urban and the combination of the two were performed with the objective of minimising the energy consumption while satisfying performance specifications, including electrical, thermal, mechanical and volumetric constraints. The physical models for evaluating performance and constraints were established, and optimisation methods and tools were delivered.
The influence of drive cycles on optimisation was also studied. It was shown that the optimization results against the NEDC and Artemis drive cycles exhibit distinct characteristics in terms of torque, speed, and energy loss distributions. Thus the optimization trends for leading machine design parameters such as split ratio, stator tooth width, turn number per coil and magnet usage to minimise total loss over NEDC and over Artemis were very different. For NEDC, the optimum design inclines to reduce high-speed copper loss and iron loss; for Artemis, it tends to minimise low-speed copper loss. Comparing the three optimised motors targeting different driving cycles, it was observed that they all have very high efficiency over a wide toque-speed range, and perform the best in their own target cycle, and with around 0.5% to 1.0% lower efficiency, or 10% to 20% higher loss in the other cycles with respect to the best efficiency. Compared to the motor optimised for Artemis, the motors optimised against NEDC and the combined cycle result in ~20% less magnet usage and a few % less copper usage, making NEDC or the combined driving cycle a preferred optimisation target.
Four fractional-slot PM candidate machines were optimised against the same specifications and constraints and their performances were compared. It was shown that the 18-slot, 8-pole interior permanent magnet machine has the best performance with low permanent magnet usage. This machine topology was therefore selected for prototype construction. The PM assisted synchronous reluctance machine for the rear motors was also optimised and it was shown that this machine benefited from lower no-load loss and low cost with NEDC efficiency comparable to that of the front motor. The two optimised machines formed an ideal combination of the distributed traction system for the HIWI power train. System efficiency maps for three designs are shown in Figure 6.
Figure 6 System efficiency maps for three optimal designs
Optimized magnetic composite 3D structure
The design optimisation route for the assessment of optimised 3D magnetic structures, was performed using both the current state-of-the-art permanent magnet materials and newly developed magnets resulting from this project, using the magnetic, thermal, and mechanical parameters obtained by characterization in WP2, and information on optimized microstructure and micromagnetic properties obtained in Task 3.2.
3.4.3 Impact on other Work Packages
WP3 provided the basis on which the optimum motor designs and configurations were determined which fed directly into WP5. The results of magnetic modelling work supported the experimental trials of exchange-coupled magnet production that targeted optimised grain sizes in the laser annealing of amorphous magnetic materials in WP2.
3.5 WP 4: Power Electronics and Control System
The objectives of this work package were
• Define an electronic architectures based on mechatronic modules solution to ensure a highly integrated, energy efficient power electronics subsystems for power conversion
• Design and development of system-based chip, planned to embedded fail-safe concepts, for MOSFET inverter bridges planned to definite brushless motors;
• Design and development of fault-tolerant smart power devices for power management/storage (DC-DC converter and inverter bridge), and for electrical motor drives
3.5.1 Work Undertaken
WP4 was delivered by three tasks.
Task 4.1 electronic architectures: subsystems for power conversion (STM, SIEMENS, CRF, USFD)
The aims of this task were to define the specification for the smart power subsystems and to define the appropriate physical architecture derived from mechatronic expertise, to ensure highly integrated, energy efficient power conversion taking in account both the constraints of novel motor solutions, and requirements of specific EV application control and safety strategies.
Several circuit topologies were analysed to define adequate parameters to meet the specification of two applications (smart power drive and power management) whilst satisfying the requirements on safety, performance, system costs, and at same time, to take advantage of energy recovery from motor on braking. Safety and communication requirements were investigated that determined specifications for flexible and fail-safe sub-systems.
Task 4.2 Smart power drive: (STM, USFD, SIEMENS)
Based on the initial optimization of PM traction machines established in WP3, design specifications/ constraints outlined in WP1 and the embedded modular architecture defined in Task 4.1 this task identified the required components (powers, driver, micro) for the smart power subsystem, and produced a prototype comprising the inverter bridges and dedicated controller with embedded fail-safe concepts, able to support high efficiencies over the wide torque/speed range demanded.
Task 4.3 Power management/storage system : DC-DC converter and inverter bridge integration (STM,
SIEMENS, CRF, USFD)
Based on the analysis developed in WP1, the findings of WP3 and the solutions adopted in T4.1 this task identified the required component, system integration and control strategies to achieve high efficiency bidirectional coupling between the drive and the accumulator pack.
3.5.2 Scientific and Technical Results
Smart Power Subsystems
The major focus here centred on the smart power subsystems with the aim to define the appropriate architecture derived from mechatronic expertise, able to ensure a highly integrated, energy efficient power conversion taking in account both the constraints of novel motor solutions, and requirements of specific EV application and control strategies. The definition of the power sub module could not be disconnected from both technologies in order to reduce the parasitic switching energy effect and EMC noise, and from the techniques of attachment/soldering to optimize thermal exchange between substrate and device and allow a drastic reduction on switching commutation loss. The objective was to develop a dedicated power module and control solutions based upon the integration of several control strategies to provide an inverter bridge for Hi-Wi, with integrated control capabilities and a DC/DC power converter for efficient energy management based upon the voltage and power requirements determined by WP1 and WP3. An ad hoc inverter was designed using a prototype power module designed to meet the objectives of Hi-Wi, and assembled on the pilot line in Catania with new power devices in Si (IGBT 200 A single die) in a dedicated redesigned structure for the ST A3 power module. The choice of power semiconductors plays a key role in power conversion applications, the increased demand for high power density and assembled reliability become a key objective. This required the need and capability to combine several technologies regarding semiconductor production processes, packaging methodologies and system know how to create a power module with the appropriate characteristics of thermal performance, power density and robustness.
Figure 7 Front and rear view of smart power module from STM
3.5.3 Impact on other Work Packages
WP3 provided information that was used in the design and development of power requirements for WP5 and WP6.
3.6 WP 5: Motor Manufacturing
WP5 was the culmination from the outputs of WP1, 2, and 3, which led to the creation of the Hi-Wi motors for testing in WP6. The objectives of this work packages were
• To manufacture prototype motors with appropriate sensors and feedback devices.
• To perform tests and evaluation
• To deliver a complete motor unit for integration into the power train unit
3.6 WP 5: Motor Manufacturing
WP5 was the culmination from the outputs of WP1, 2, and 3, which led to the creation of the Hi-Wi motors for testing in WP6. The objectives of this work package were
• To manufacture prototype motors with appropriate sensors and feedback devices.
• To perform tests and evaluation
• To deliver complete motor units for integration into the power train
3.6.1 Work Undertaken
Work in WP5 consisted of five tasks.
Task 5.1 Prototype motor manufacturing (SIEMENS, USFD, UCAM, CRF, IPM)
Prototype motors were manufactured using a modular design approach. One type was manufactured using conventional hard magnetic materials to demonstrate the new topology, whilst a second type evaluated the techno-economic benefits of the low rare-earth magnets developed in WP2. Trial tooling and jigs were designed and constructed to explore the rotor manufacturing process required by the new magnetic materials. The iron core and the windings of the electrical machines were manufactured using the best and most cost effective material supply chain. Volume manufacture experience supplied by SIEMENS ensured that particular care was taken regarding the detailed mechanical design of the parts (magnets, core, windings) such that easy and low cost manufacturing could be achieved whilst preserving very high power/torque densities.
Task 5.2 Mechanical integration (USFD, CRF)
Motor enclosures were designed and manufactured. The preferred option was air cooling, although a
detailed trade-off study was performed to compare this and other options with respect to reliability, cost and ease of manufacturing. The rotor assembly units were integrated into the mechanical enclosure and the assembly along with integrated feedback devices for temperature, position and speed.
Task 5.3 Preliminary test (SIEMENS, USFD, CRF)
Comprehensive testing of the prototype machines and drives using prototype inverters under representative operating conditions was undertaken on a dynamometer available within the consortium. The results were used to validate the models, control strategies and theoretical performance predictions, and to assess the techno-economical benefit of the developed traction drive technology and hard magnetic material. Mechanical (vibration, over-speed) tests were also performed on the test bench. The further steps necessary for commercialisation of the developed motor drive technology were identified.
Task 5.4 Motor + power converter assembling (USFD, CRF, STM, SIEMENS)
- The outcome of Tasks 5.1 5.2 and 5.3 were integrated into a complete drive unit ready for testing in WP6.
Electric motor design report
This report summarised the electromagnetic and mechanical designs of the front and rear motors for the Hi-Wi traction system. Finite element analysis (FE) predicted the performance of the motors over the various driving cycles and at typical operation points. Demagnetisation risk, thermal limits and mechanical stress under extreme operating conditions were assessed, and the mechanical drawings for the key components and enclosures were presented including motor parameters for subsequent modeling and control.
With the objective to achieve high energy efficiency over a wide torque-speed operating region, the Hi-Wi power train employed two different electrical machine technologies/topologies for traction. Torque distribution between the front and rear axles through dynamic apportioning enabled additional energy saving. The motor developed for the front axle employs an interior-mounted permanent magnet machine (IPM) with innovative fractional slot windings for its high torque and power density, and a permanent magnet assisted synchronous reluctance machine (PMA SynRM) with low high-speed loss was selected for the two rear motors. The designs for both types of motor were generated following systematic optimisation and performance evaluation.
Hi-Wi front motor
The machine topology of the front motor, an interior mounted permanent magnet machine with 18 stator slots and 8 rotor poles, is shown in Figure 8. The coil sides of the 3-phase windings were placed in the stator slots in superposition. The magnets were embedded in the rotor lamination in a V-shape to enhance torque production capability through the reluctance torque and to improve field weakening capability for high torque and wide operating speed range. The key merits of this novel machine topology were detailed in deliverables D3.2 and D3.4 of WP3. The efficiency map over the torque-speed operating envelope is shown in Figure 9 and the complete motor assembly is shown in Figures 10 and 11. Efficiencies from 94% to 97% can be achieved over a wide region with the torque up to 50 Nm, and speed up to 5000 rpm.
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Figure 9 Efficiency map of the Hi-Wi front motor
Figure 10 Complete Hi-Wi front motor design
Figure 11 Hi-Wi Front motor
Hi-Wi Rear motor design
According to the comparative and optimisation studies performed in WP3, the Permanent Magnet Assisted Synchronous Reluctance Motor (PMa-SynRM) appeared to be a highly suited topology for the rear motors of the Hi-Wi drive train. The presence of low-cost ferrite magnets in the rotor allows this topology to achieve a higher power factor and torque density compared to a purely synchronous reluctance machine (SynRM). The low remanence permanent magnets embedded in the rotor result in a relatively low torque density, when compared to conventional PM machines with rare earth magnets, but the outstanding field weakening capability of this topology can compensate on the power density. The low manufacturing cost as well as high reliability and fault-tolerance capability due to the weak embedded PMs (viz. ferrite or bonded NdFeB) were additional attractive features that favoured this choice for the rear motors of the Hi-Wi drive train. A 2-D cross section of the PMa-SynRM is illustrated in Figure 12.
The traction machine and combined system (machine & inverter) efficiency maps (EMAPs) along with the NEDC and Artemis representative points are depicted in Figures 13 and 14 respectively. As can be observed from the figures, the majority of both driving cycles’ representative operating points are located in the higher efficiency regions. The complete assembly of the rear traction machine is shown in Figures 15 and 16
Figure 13 Traction machine efficiency map with driving cycles’ representative points
Figure 14 System (machine & converter) efficiency map with driving cycles’ representative points
Figure 15 Complete assembly of Hi-Wi rear traction machine
Figure 16 Hi-Wi rear traction motor
Functional test report on motor units
In the Hi-Wi project SIEMENS performed comprehensive testing of three prototype machines (two rear motors and one front motor) under representative operating conditions. The front motor was tested with two different rotors. The first rotor of the front motor was equipped with conventional magnets. The second rotor used the new magnetic material developed in WP2. The tests were performed with a preliminary inverter on a test bench with a speed variable dynamometer, as shown in Figure 17.
Figure 17 Test stand for electrical machines
The tests confirmed that the real motor data fits well with the calculated data. The efficiency at continuous load was measured at 87 % for both Hi-Wi rear motors, whilst the HiiWi front motor efficiency at continuous load was measured at 91 % with the rotor using conventional magnets and 93 % when using the rotor with the new magnetic materials.
3.6.3 Impact on other Work Packages
WP5 has shown with great certainty that the work carried out in specifying the system in WP1, the development of the new low-level rare earth magnetic materials in WP2, the simulation and modelling in WP3, and the motor design and manufacturing in WP5 have demonstrated excellent results.
3.7 WP 6: Drive Integration, Electronic, Mechanical Coupling
WP6 brought together and built upon the outputs of WP1 to WP5 and had the following objectives
• Mechatronic module integration
• Enclosure, cooling system and cinematic coupling design and implementation
• System assembling, testing and validation
• Automotive qualification strategy against robustness requirements definition
3.7.1 Work Undertaken
The work in WP6 was delivered through 6 tasks
Task 6.1 Electronic power drive and motor integration strategy (CRF, STM, USFD, SIEMENS)
This task provided definition of an integration strategy for the power electronic drive designed and manufactured in WP4 and the electrical machine designed in WP3 and manufactured in WP5 in terms of overall reliability, accessibility for maintenance, electric and magnetic field emissions, cooling and power dissipation needs.
Task 6.2 Structural properties of the electrical machine analysis and assessment (CRF, UCAM, USFD)
The electrical motors were studied against mechanical specifications in terms of structural strength, vibrations and noise by means of CAD-CAE techniques. Configurations with conventional and novel materials were assessed against automotive requirements.
Task 6.3 Drive Package and Cooling system design and implementation (CRF, SIEMENS, USDF)
With the final goal to address a modular power train system composed of independent globally optimized accumulator-electronic drive-motor blocks, the cooling system for the accumulator pack unit, the electrical motor and power electronic unit were designed according to criteria defined in Task 6.1.
Task 6.4 System final assembling, test bench design and manufacturing. Test procedures (CRF, SIEMENS, STM)
The subsystems were to be assembled in a package having mechanical (flange) and electrical (connectors) interfaces easy to connect with the wheel, the central charger and the main sensing and management system unit of the powertrain system as a whole. A test bench for the functional dynamic evaluation of the single power-train block was designed and implemented. Proper test procedures were defined first to assess the system against the specification and the criteria defined in WP1 and secondarily to envision future full automotive qualification and compliance with regulatory issues. A test bench was designed and implemented.
Task 6.5 Testing and final debugging and assessment (CRF, SIEMENS, STM)
The final system debugging was performed, and a complete test plan was implemented according the test procedures defined in Task 6.4. The results of the testing were analysed and evaluated against the validation criteria.
Task 6.6 Robustness validation strategy planning and preliminary robustness validation by simulation (CRF)
A preliminary validation plan was prepared by means of simulation tools to identify parameters for the future implementation of a full automotive qualification against robustness validation guidelines.
3.7.2 Scientific and Technical Results
Power drive integration strategy
This objective was met through processes of theoretical design, CAD/CAE simulation, the construction and interconnection of some elements of the system where appropriate, the generation and embedding of software, the bench testing of physical prototypes and the examination of materials and structures to determine their suitability for automotive use
Drive package and cooling system
Different power train strategies were considered along with their drawbacks and advantages according to CRF studies The power train used in the vehicle of a related project (WIBEMOB) was also considered. The CAD data of the WIDEMOB power train was used as the base for the simulation of the air flow and the thermal consideration on the inverter and motor, according to the mission profiles presented in WP1. The Fiat 500 hybrid battery pack model was used to study the impact of incorporating a super capacitor on the lifetime of the batteries when the mission profiles developed in WP1 were applied. The matrix of simulations and studies provided a wide-ranging view of the potential performance of the Hi-Wi motor/inverter if it were to be incorporated into the WIBEMOB vehicle. The simulated integration of the WIDEMOB vehicle and the Hi-Wi system (front and rear inverters/motors) assessed the local heat exchange coefficients and fluid temperatures taken at a specified distances from the surface of the corresponding elements. The simulation was performed with StarCCM+ at the following speeds: 5-15-35-65-95-115-135 km/h. The 3D data for the simulation were those derived from the integration analysis of the WIDEMOB vehicle with the Hi-Wi inverters and motors. The skin temperatures of the electric motors and inverters were taken into account and imposed to 100 °C. Figure 18 shows a section across the resulting 3D model.
Figure 18 WIDEMOB vehicle with HI-WI inverter and motor integrated, simulated air speed around the vehicle and under the boot and bonnet at a speed of 5 km/h
Structural properties of magnetic material
The flexural strength and hardness of the Hi-Wi magnets were assessed and compared to the original substrate material, substrates which have undergone heat treatment without having been coated with dysprosium and manufacturer supplied data for the substrates. The untreated substrates and the Hi-Wi magnets did not show a significant variation in strength.
Drive unit assembly
The aim was to assemble the complete Hi-Wi e-drive, with electrical and mechanical interfaces. After a series of preliminary tests of each available component of the powertrain, a representative system was assembled on a customized test bench, in order to validate the system against the specification and the criteria defined WP1. The test bench arrangement was focused for efficiency verification of the powertrain over the three specific driving cycles
• Urban cycle;
• Extra-urban cycle;
• Up&Down Hill cycle.
In order to implement this dynamic test CRF developed specific devices for the installation, including the supply and the cooling of all the Hi-Wi powertrain. The output of the tests were a detailed efficiency map over the three different cycles and the average value was well matched with the predictions.
System Tests
Through test runs of the Hi-Wi e-drive it was possible to verify the performance and efficiency over specific working cycles. The defined cycles were divided into two different categories, the first one was linked to real usage of a pure electric vehicle (Urban, Extra-Urban and Up&Down Hill cycles) and the second was linked to the homologation environment (WLTC Class 2 and NEDC Cycles). The complete electric powertrain was able to run over all the defined working cycles without any thermal problems. Excellent average efficiencies were detected and confirmed by the on bench test over WLTC Class 2 and NEDC cycles.
3.7.3 Impact on other Work Packages
The goal was to confirm and validate the system against the specification and the criteria defined WP1. In addition, the tests link directly to other work packages that were responsible for the new magnetic materials WP2, validation of design and simulation outputs in WP3, and motor design and construction in WP5. The results from WP6 validated all of the Hi-Wi research outputs and mark the success of the overall programme.
Potential Impact:
4 The potential impact and main dissemination activities
4.1 Background
The top-level aim of the Hi-Wi project was to accelerate the deployment of electrical mobility by merging, at the European level, public and private resources to develop highly-efficient next-generation powertrain systems. Hi-Wi outputs have exploited breakthrough developments in nanotechnology, magnetic materials, motor topology, and smart systems integration.
Electrical vehicles for personal mobility will profoundly affect every walk of life, trigger significant changes in electricity distribution and the marketing of automobiles, and potentially bring major benefits for the economy, the environment, health, family and leisure.
Electric vehicles also promise to reduce vulnerability to trans-national fuel supply chains, but there is a danger of substituting this problem with new obstacles in the securing of Rare Earth Element magnetic materials, a concern that has been addressed by the more efficient motor design topologies and advanced materials research outputs from the Hi-Wi project.
The foregoing prospects for societal gain and greater energy/materials autonomy for the EU make it imperative to define, review and lay down the fundamental principles of electric drive trains - from the energy store to the traction wheels - with the utmost care.
The Hi-Wi team engaged with the high-level architecture of the powertrain as an immediate priority, for it is only in the context of a new and appropriate framework that the optimum direction can be determined for advances in materials, production processes, motor design and control systems.
For the first time in the history of mechanised mobility, technological advances, driven by electrification, electronics, advanced materials and software, have reached a level for full optimisation of the performance and efficiency of an integrated powertrain, across the full range of real-life driving conditions.
Electrical mobility is widely recognised as the route to save the primary energy consumed in transportation. Moreover, efficiency gains are generally acknowledged to minimize the use of natural resources, whether exhaustible or renewable. However, the real drive for the uptake of the electric car will be economics. Even a single 1% increase in powertrain efficiency will bring about a 1.3% reduction in the weight and cost of the battery pack. With a 20 kWh pack costing some €7,000 this saving amounts to €90, which is higher than the cost of the motor.
This example illustrates just one of the multiple knock-on impacts of improvements in powertrains. But without such basic economic advantages to push the adoption of electrification, none of the hugely beneficial environmental, societal and broader economy advantages can be realized.
The Hi-Wi objectives of delivering HIGHer efficiency across a WIDE operating region promises efficiency gains well beyond 1%, across a full range of driving conditions and with reduced dependence upon vulnerable supply chains were ambitious and yet were met with resounding success.
4.2 Impact on Electrical Machines
The FP7 Work Programme for electrical machines (GC.SST.2010-7-1) stated that, “The successful introduction of electric vehicles in the market requires the development of electric machines that are at the same time cheap and highly efficient (on a wide torque/speed range) with high power to weight and volume ratios. At the same time they should also be reliable and robust, in order to withstand the harsh environmental and usage conditions imposed by the automotive standards achieved with the internal combustion engines”. The topic advocated the development of electronic architectures, compact/miniaturised mechatronic modules and highly integrated, energy efficient power electronics technologies and subsystems for power conversion.
Exploring innovative topologies and concepts (including consideration of intrinsic fault tolerance or methods to cope with unavoidable faults) for the various types of applications (from in-wheel to stand-alone or engine-integrated ones), was a significant challenge. Hi-Wi addressed these challenges through Work Packages 1, 3, 5 and 6, which respectively delivered the overall architecture, novel motor topologies and their assembly processes, and schemes for in-vehicle integration. The motor topologies targeted a significant reduction of the reliance upon Rare Earth Element magnetic materials, avoiding potential cost hikes and supply chain disruption. Researching high performance magnetic materials design and production, WP2 and WP3 investigated the synthesis of novel magnetic/composite as pre-formed bulk components, and modelled their properties and behaviour. The development of these materials have, as for the motor topologies, significantly reduced reliance upon Rare Earth Element magnetic materials, with savings in Dy content of 75-84% overall for the same coercivity, and a 5% improvement in remanence which offers improved motor torque.
Defining simplified, high efficiency cooling concepts was met by Hi-Wi through its twin objectives of optimally partitioning the motive power and gaining HIGH efficiency over WIDE operating conditions. This will allow future EU EVs to have superior operating performance over competing vehicles.
Developing advanced magnetic modelling tools through WP3 by the work of IPM (world leaders in this field) will greatly enhance EU competencies in this area by offering non-specialists the ability to design optimised magnetic systems
New automated manufacturing concepts developed in Work Packages 2, 5, and 6 , have delivered a blend of manufacturing process opportunities, ranging from disruptive and speculative through to incremental engineering development. These impacts will offer EU industries a distinct competitive advantage in delivering efficient manufacturing processes.
4.3 Hi-Wi Impact upon the Introduction of Electric Mobility
Electrified mobility is currently a top priority in the US, Japan, China, Korea and EU. It promises to introduce a radical industrial change in our society, as new technologies and infrastructure are put in place over the next two decades. The transition phase is now starting, with a growing awareness that the underlying technology to implement electrical mobility is reaching a sufficient level of maturity. There is now a push at many levels (global, EU, national, organisational) to refine and implement enabling technologies and systems so as to effect a platform for fundamental change to our road transport paradigms and to embrace the possibilities promised by the transition to electrical vehicles. The promises behind the move to electrical mobility are:
Reduction in oil consumption,
• “Well to wheels” energy efficiency is the key factor;
• The potential economic benefits are significant;
• In Europe 73% of all oil is consumed by transport. Road transportation accounts for over 85% of this
Improved safety of road transport,
• There are 5 lethal accidents every hour, and road accidents are the main cause of death in the under-45 age group, besides
• Electrification offers the opportunity to incorporate radical new safety paradigms with innovations in systems design and communications structures.
Reduction in emissions and noise produced by road transport,
• Environmental benefits, including mitigation of climate change risks;
• Public health benefits;
• According to the WHO, noxious gas emissions emitted by cars cause an even higher number of deaths that those caused by road fatalities. Electrical mobility eliminates noxious gas emissions in cities;
• electrification offers the opportunity to incorporate radical new safety paradigms with innovations in systems design and communications structures.
In the context of burgeoning vehicle electrification, the EU now has an opportunity to compete effectively in a global context. The strengths of EU innovators in embedded systems design, nanoelectronics and systems integration could be exploited further to be assured of a significant European stake in the massive market that is set to emerge in the coming decades. The Hi-Wi project has provided underpinning science, understanding and practical developments to exploit this opportunity.
Referring to the recent electrification roadmap released by the three EU platforms ERTRAC, EPoSS, SmartGrid, the impact of the electrical mobility compared with conventional transport can be usefully quantified in terms of energy and resource security, climate change, public health, freedom of mobility, and economic growth:
Primary energy savings Due to the EU’s growing dependency on primary energy sources this parameter is very likely the most motivating one. 73% of all oil in the EU (and about 30% of all primary energy) is consumed by the transport sector. Biofuels and natural gas are making an important contribution to fuel security, however only for a small fraction of the total needs.
To quantify the technological evolution that makes electrical mobility appealing we take as reference an ideal powertrain of a vehicle whose energy consumption depends only on mass, aerodynamic drag (frontal area and Cx) and the rolling resistance of the tyres. We suppose that for the New European Driving Cycle (NEDC) such a vehicle will consume 120 Wh/km. The amount of primary energy consumed by such vehicle depends on the chosen cycle and varies in relation to the typology of the powertrain and the need of energy for cooling or heating. Hi-Wi has made significant advances in these aspects of power train design and operational efficiency.
The peak efficiency of an electrical motor at defined power and torque values can reach 95%, compared to 45% for an internal combustions engine. In electrical motors this may drop to below 60% in extreme cases, but an electrical powertrain can be designed to be intrinsically less sensitive to the characteristics of the driving cycle. For instance, by using more than one motor the average efficiency can be kept at above 90% for a large range of delivered powers and torques. Hi-Wi has delivered motor efficiencies of some 93% using the new magnetic materials.
The overall combined efficiency of power switches, DC-DC and DC-AC inverters can reach 90% whilst that of motors and gears depends on the chosen driving cycle with typical values ranging from 80% for driving cycles requiring large excursions of power and torque to 86% for smoother cycles. In conclusion, from the battery to the wheel, the modern electrical powertrain can promise efficiencies in the range of 72%-77%. The outputs across all of the technology innovations in Hi-Wi have greatly in increased the performance of EV systems and as such could have a significant impact on the take-up of EV power trains in personal mobility applications.
Reducing Green House Gas Emissions Vehicle emissions contribute to the increasing concentration of gases that are leading to climate change. In order of significance, the principal greenhouse gases associated with road transport are carbon dioxide (CO2), and methane (CH4). In the EU the transport sector causes 26% of all GHG emissions due to human activities. Although these are only 4% of the total GHG emissions, they accumulate in the atmosphere as the ecosystem is unable to react-compensate at the same rate of change as human activities have brought about in the last one hundred years.
The transport sector is the fastest growing source of greenhouse gases, and of the total from transport, over 85% are due to CO2 emissions from road vehicles. Therefore, they are considered a major sector to attack for a limitation of GHG emissions. Well-To-Wheel CO2 emissions for electric vehicles are some 60% of those resulting from comparable Internal Combustion vehicles. This mirrors the comparison for Well-To-Wheel energy consumption
Reducing noxious emissions (raising public health) Road transport causes emissions of nitrous oxide (N2O) and also remains the main source of many local emissions including benzene, 1,3-butadiene, carbon monoxide (CO), nitrogen oxides (NOx) and particulates (PMs).
Within urban areas, the percentage of contributions due to road transport is particularly high. There is a growing body of evidence to link vehicle pollutants to human ill health including the incidence of respiratory and cardio-pulmonary disease and lung cancer. In general, according to the World Health Organisation, emissions from car exhausts are responsible for more deaths than road accidents. EVs eliminate all the side effects due to the burning of hydro-carbon in conventional vehicles.
Global competitiveness The development of new architectures from the Systems Integration point of view is the aspect that more than any other will defend the competitiveness of EU companies against those of the USA and Asia.
The next generation of Electric vehicles offers the chance to implement a radical new concept for the control architecture based on distributed propulsion and purely electrical power supply and distribution. Based on this paradigm change, EU industry will be in a commanding position to lead the exploitation of innovative mobility solutions.
The impact of Hi-Wi will be seen in changed supply chains in the automotive industry, in new market entrances and value creation among the production lines.
The outputs of Hi-Wi will contribute to the development of a European standard reference technology platform for electric vehicle design, which contains architectures, models, methods, and tools for real time embedded system development, verification, validation and testing.
Supply chain security Electric vehicles promise to reduce vulnerability to trans-national fuel supply chains, but there is a danger to substitute this problem for new obstacles in the securing of Rare Earth Element magnetic materials. Hi-Wi has greatly reduced this vulnerability, addressed by the project’s more efficient motor design topologies and advanced materials research outputs.
Benefits through partnership The Hi-Wi project has grown the capabilities of its European partners, enhancing the quality and reliability of European smart integrated systems, architectures and platforms for the design of next generation electrical and hybrid vehicles. The project will have a direct impact on reducing the design cycles, the development costs and time to market of electric vehicles. This will also include the development of accelerated test methods and enhanced qualification strategies. The industrial partners will see these benefits through elevations in market position, and these successes will pass down the supply chain. Research partners will gain valuable expertise to aid further the industry.
4.4 Dissemination Activities and Exploitation of Results
During the course of the Hi-Wi project, multi-stranded dissemination activities took place aimed at promoting its research and at reaching the widest and varied audience possible. The dissemination plan (Task 11.1) was written by UCAM, with contributions from all partners, and sent to the project coordinator in March 2011. The plan defined the audience for dissemination, and some key dissemination tools and dissemination activities:
• Management meetings, bilateral meetings and review meetings
• Shared workspace
• Contact with the supply chain regarding project requirements
• Web site
• News bulletins, Review publication and Journal / Conference papers
• Conferences, EU Technology Platform and brokerage events, Industry groups
• Use of deliverables, particularly those based on industry insight, to inform researchers and students/trainees
All individual presentations are stored in the restricted shared workspace, and thus accessible for all project partners to use as appropriate. Standard templates were used when creating the presentations to make sure that a unified identity was preserved to maximise recognition and impact.
4.4.1 Dissemination material and tools
1. Official project website
The official Hi-Wi project website has been available since month 2 of the project at www.Hi-Wi.eu.org. The objective of this website is to provide information regarding the project addressed to the public. It contains: a brief introduction to the project’s aims, objectives and Work Package activities; A review of the project’s publications; Robust and expansive statements regarding Applications and Licensing The website was created and updated by UCAM (with support of all participants), and will be maintained and hosted by UCAM after May 2014.
2. Logo, PPT and deliverable templates
A logo was created to maintain the corporate identity of the Hi-Wi project. Templates for Power Point presentations and deliverables were designed to ensure a united presentation to those external to the project.
3. Avenues for Knowledge flow and dissemination
The avenues that were indentified were:
• Sharing of knowledge between partners and diffusion throughout their organisations
• Engagement with the commercial supply chain and user organisations
• Engagement with the research base
• Informing of strategists within industry and the research base
• Skills delivery through the provision of informative reference/teaching/training materials
During the project the partners learned much from each other, and in particular some of the deliverables from industry greatly informed the university researchers, to an extent where some deliverables could become teaching aids.
4. Knowledge channels
Six categories for dissemination were chosen, Figure.19 being distinct from the task-orientation of the Work Packages. This approach allowed a more “generic” targeting of the project outcomes, which, as it transpired during the project, promised application wider than just the Electric Vehicle domain.
Figure 19 Knowledge channels
5. News bulletins
A simple 2-page format enabled quick customisation for distribution at conferences and industry events.
6. Review publication
A comprehensive document aimed specifically at potential users of the project outcomes
7. Journal and conference papers
Extensive publications, especially towards the conclusion of the project when outcomes could be described
8. Conferences, EU Technology Platform and brokerage events, Industry groups
In addition to the research conferences recorded, project personnel attended and contributed to a number of industry events.
List of Websites:
5 Website and Contact
5.1 Website
The Hii-Wii website can be found at the following link:
http://www.hiwi-eu.org/
