Community Research and Development Information Service - CORDIS


HASTECS Report Summary

Project ID: 715483
Funded under: H2020-EU.

Periodic Reporting for period 1 - HASTECS (Hybrid Aircraft; academic reSearch on Thermal and Electrical Components and Systems)

Reporting period: 2016-09-01 to 2017-11-30

Summary of the context and overall objectives of the project

The general objective of the HASTECS (Hybrid Aircraft: Academic research on thermal & Electric Components & Systems) project is to support Hybrid Electric Demonstration by developing models and tools that can help the designers in assessing main benefits of architectures and power management. Assessments will be integrated at the system level and will include design and analysis of the main components of the hybrid power chain: electric machines and its cooling, cables, power electronics and related thermal management by taking into account the main environmental constraints, especially partial discharges due to new high power and ultra-high voltage standards. For that purpose, we propose:
- To optimize performance of electric and thermal components in terms of specific power (kW/kg) or specific energy for storage components (batteries, fuel cells). The energy efficiency of components and of the whole system with its power management is a second major objective;
- To integrate main constraints imposed by the environment; partial discharges and thermal cooling will be mainly focused with regard to environment conditions (external temperature, pressure, humidity, air speed) in the nacelle as in the fuselage;
- To provide tools and models for studied components (electric machines, cables, power electronic converters, storage devices or fuel cells) and to simplify these models for system integration studies. The objectives of the latter aim at helping architecture designers and will participate in knowledge transfer.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

"During the RP1 reporting period (Sep 2016 – Nov 2017), the main progress related to the general objectives of the HASTECS project are:
- A target setting tool called “Scaling Rules” has been developed for electric machines preliminary design. This tool can define the main loads of an electric motor to reach some defined targets in terms of specific power. These loads define the level of technologies required to reach these targets. To assess the validity of this tool, analytical models have been developed to make a sizing tool for surface mounted permanent magnet synchronous motor (SM-PMSM). Finite element methods have been used to validate the whole sizing procedure. For sinusoidal radial flux non salient permanent magnet motor the sizing procedure calculate the losses accurately and can be already used to make a good sizing of motor of specific power of 5kW/kg.
- The development of a design tool for power converters has been launched, especially for voltage source inverter design. We are now able, for classical and known topologies (state of the art) and using silicon-type components, to quickly evaluate performance and efficiency for a given operating point or for a sequence of operating points that may represent a mission. The effects of the DC bus voltage level on both sizing and performance of the associated converters have been studied leading to provide recommendations of an ""optimal"" range for the DC bus voltage for all topologies.
- Another research is related to innovative solutions for machine cooling. A thermal model was developed to predict temperatures and heat fluxes inside the motor and to quantify the effect of different cooling methods. The thermal model (steady and/or transient states) was developed in Matlab software from scratch, based on a nodal network. It allowed obtaining local temperatures and heat fluxes for each design according to machine losses and other thermal conditions. For power electronic converter cooling and to achieve ambitious objectives in terms of specific powers, only innovative high efficiency solutions have been taken into account. Researches were performed on different cooling systems to understand which one represents the best solution for this application. Because of the strict relation between cooling system and coolant fluid, a research on different conventional and non-conventional fluids was performed to select the ones that could work better with the highest performance. Because of the high efficiency and reduced weight of passive cooling systems, tests were performed on a CPLIP (Capillary pumped Loop for Terrestrial Applications) to have more reliable values of evaporator conductance to have a first approximation junction temperature value for a converter configuration (the junction temperature is one of the parameters used to choose a power converter configuration).
- Another WP dedicated to partial discharge studies has just started since October 2017 (2 months during the RP1). The main result is related to first numerical simulations of electric stresses on the basis of single wires configuration.
- Integration of simplified models has been launched by integrating PWM inverter – PMSM (Synchronous Motor) association. The power converter design tool has been encapsulated while a sizing motor model has been fitted with respect to the target setting tool called “Scaling Rules” developed by the WP1. From Airbus data, development of simplified (surrogate) models for Gas turbine (turboshaft), propeller, gearbox and cables has been launched. Finally, a complete design process for overall simulation of the hybrid power chain has been defined by setting inputs/outputs for each device.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Beyond the state of the art, the HASTECS project two successive targets in view of minimizing specific powers of the power chain:
a “medium term target for 2025” is currently studied with reference to the state of the art. In particular, most performant components and materials currently existing will allow to increase power densities, targeting 15 kW/kg for power electronics (inverter for drives, DC-DC chopper for storage devices) and 5kW/kg for electric machines (including cooling). The cooling of power converters and electric motors will be a key issue to address such targets; A review on the cooling solutions has been achieved which records the different existing cooling methods that could be applied to the electric motors for 2025.
Then, we will have to propose new concepts associated with several technological breakthroughs of the main components for a “long term target of 2035”. As an example, new wide gap power components (for high temperature compatibility) inserted in advanced power electronic structures allowing a power partitioning of switching cells (multilevel converters) will be fully integrated within the machine design. For power electronics, the specific power target is 25kW/kg and 10kW/kg for electric machines (including cooling).
A set of breakthrough improvements will be necessary to reach these targets; innovative technologies and concepts in machine cooling and thermal management system constitute a key challenge to reach these goals: the consortium expertise is based on this finding, strongly coupling research teams with a transdisciplinary (“electro-thermal”) vision.
NB: reaching such aggressive targets would lead to major positive consequences to the environment with consistent reduction of fuel burn during flight and noise reduction on ground with full electric taxiing; As an example, crossing the expected gap in terms of specific powers from 2025 and 2035 when installing 4 inverter–motor drives of 1.5MW, would lead to a weight reduction of 1.8 tons which would offer a fuel burn reduction estimated at 3% for a short range (~300 nm ) flight !

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