Electric Machines with Inherent Speed-Dependent Characteristics for More Sustainable and Efficient Energy Conversion

Project Information

CHARMAELEON

Grant agreement ID: 101078304

DOI

10.3030/101078304

EC signature date 15 February 2023

Start date 1 April 2023

End date 31 March 2028

Funded under

• European Research Council (ERC)

Total cost

€ 1 499 921,00

EU contribution

€ 1 499 921,00

Coordinated by

UNIVERSITAT LINZ
Austria

Periodic Reporting for period 1 - CHARMAELEON (Electric Machines with Inherent Speed-Dependent Characteristics for More Sustainable and Efficient Energy Conversion)

Reporting period: 2023-04-01 to 2025-09-30

Summary of the context and overall objectives of the project

Half of the total electric energy consumed within the European Union is used for operating electric machines. Those might feature high efficiency for rated load, but partial load and overload performance often is very poor. Additionally, given some voltage and current limits for driving machines, designers need to trade good performance at high torque versus high-speed capabilities.
Machines with speed-dependent characteristics would facilitate overcoming the current limitations and thus are the subject of this ERC project. The main approach for realizing operation dependent machine characteristics is to acquit oneself of thinking that the electric machine structure must be static. Allowing solid parts of the rotor to change in position or powder-based compounds to vary in local density while rotating enables a new class of designs. The realization requires all-new methods for designing the speed-dependent properties. This embraces techniques for co-simulating mechanical and electromagnetic aspects including components’ or particles’ movement, the experiment-driven characterization of powder-based softmagnetic materials with variable local density, micro- versus macroscopic modelling of magnetic properties, and the development of promising concepts for future electric machine design and their experimental proof of concept. The basic idea is simple, but its effective implementation is challenging and requires pioneering cross-disciplinary research.

The gained results will allow for simultaneously achieving higher net efficiency levels and reducing the consumption of resources due to an improved utilization of the applied components. The project will thus help to reduce the overall energy consumption and to minimize the need for critical raw materials. The reward of this project is tremendous and the expected outcome will beneficially affect our future lives.

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

In alignment with the objectives indicated in the project proposal, significant advancements in the design, evaluation, and characterization of innovative electrical machine technologies and materials have already been achieved.

A computationally efficient framework for simulating the start-up processes of line start machines was developed, incorporating a finite element-aided analytical model. This model accounted for position-dependent and saturation effects, enabling a parameter study to evaluate start-up performance under various grid conditions.

In parallel, a sophisticated technique for evaluating variable flux machines (VFMs) was established, considering different flux linkage levels. Two novel VFM concepts with moving parts to vary rotor flux linkage were proposed and analyzed. A detailed investigation into the design and functionality of these moving parts led to an improvement strategy for the proposed machines. Additionally, a machine concept utilizing additive manufacturing and composite materials was explored, aiming to enhance magnet utilization and reduce reliance on rare earth materials. A laboratory model was built and successfully put into operation. Measurement results confirm the superior performance concerning the inherent speed dependent flux weakening capabilities.

The project also addressed the challenges of characterizing feebly magnetic powders (with low relative permeability, μr≈1−20), which are promising for electrical machine design but present significant difficulties due to the high stray flux sensitivity of the characterization process. To overcome these challenges, a novel measurement setup was developed, featuring slotted ring specimens and a two-part coil design. This system streamlined sample handling, eliminated the need for individual coil winding, and ensured accurate field quantity determination through an iterative signal model validated by 3D finite element analysis. Complementary numerical investigations guided the design of the measurement setup, including a specific sample container and a local B-field measurement approach, enabling precise magnetic characterization of powders.

Overall, the project already delivered innovative machine concepts, advanced evaluation methods, and novel characterization techniques for soft magnetic materials, contributing to the development of more efficient and sustainable electrical machines.

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)

The research project has delivered promising results with significant potential impacts on the design and optimization of electric machines, while also identifying key areas for further development to ensure broader uptake and success.

The development of a computationally efficient framework for simulating machine start-up processes and the proposal of several distinct line-start machine topologies highlight the potential for advancing energy conversion systems. Simulative evaluations suggest that these innovations lead to more efficient and sustainable machine designs. Experimental validation remains a critical next step, and a dedicated test rig has already been designed and successfully put into operation. Building proof-of-concept laboratory models will be essential to fully understand the benefits and limitations of the proposed machines, requiring funding for prototyping and testing of various components. Additionally, further research into machine behavior, geometry optimization, and validation through measurements will be necessary to refine the designs and facilitate their adoption.

Concerning inverter-fed permanent magnet synchronous machines, based upon the results of a developed design and optimization process, a laboratory model was defined and built. First measurement results reveal an excellent performance and the inherent flux weakening capability was successfully demonstrated. The evaluated performance is in alignment with simulation results. In contrast to the state of the art, here the flux weakening is achieved without the need of any active control. Consequently, this simple yet effective concept is a promising candidate to solve future challenges in electric energy conversion.

The novel measurement system developed for low-compressed magnetic powders has significantly improved the accuracy of electromagnetic parameter estimation, including AC magnetization curves and loss behavior, for materials with relative effective permeability values ranging from 1 to 20. This advancement enables reliable characterization of low-density magnetic materials, which are otherwise challenging to analyze when using conventional methods. The results demonstrate that the permeability values strongly depend on microscopic particle properties, such as size and shape, and that the system can measure up to 1.2 T at low frequencies. These findings open new possibilities for optimizing electric machine designs by incorporating adaptable ferrous powders, potentially enhancing machine performance across a wide operating range.

Overall, the project has laid a strong foundation for innovation in electrical machine design and material characterization. To ensure further uptake and success, key needs include conducting experimental validations to fully understand the performance of the proposed machine topologies and advancing methods to incorporate the electromagnetic behavior of powder-based materials into the design process for electric machines. These efforts will be critical to translating the research outcomes into practical applications with a transformative impact on energy conversion technologies.