Reliability and high torque and power density motor – REdHat_Motor

The electric driving chain constitutes a solution for mobility issues. For economic, ecologic and energy reasons, their power and their torque, with respect to their mass and volume, must be improved, and especially the electrical machines equipping the vehicles. The main goal of the project is to identify, design and test a new reliable electric machine topology that brings a significant increase in terms of torque and power densities compared to the state of the art. The goal of the partners is to reach – that’s a scientific challenge – ratios of power to mass and torque to mass of 15 kW/kg and 12Nm/kg (active parts) in continuous operation with a TRL6.

This goal will be achieved with a double approach. Firstly, a compact axial flux synchronous machine equipped of permanent magnets will be designed to work with high current densities and, thus, with high temperatures. The promising electric motor topology will be optimized, both mechanically and thermically, and inorganic insulation materials will be used. Secondly, the structural reliability of this kind of insulated winding will be analyzed by testing samples and radial flux synchronous machines under electrical and thermal constraints and mechanical stresses.

These objectives require to spread a large spectrum of skills grouped by the consortium constituted by partners of different natures:
- A research lab (LSEE) that has strong experiences in using electrical steels adapted to machine topologies and in developing and testing windings with inorganic insulation materials;
- an independent testing center (CRITTM2A) involved in the testing of all kind of vehicles like HEV and BEV;
- An institute (IFPEN) which has a strong background in designing and prototyping high power density electric drives especially for automotive applications;
- A company (EREM) which is full of experiences in the design of mechanical parts and for manufacturing very specific prototypes.

The project is simply divided in 5 Work Packages:
- WP1 consists in identifying the most adapted materials, including electrical steel and insulation. The axial and radial flux machine will be designed;
- WP2 groups the manufacturing of the winding samples, the radial machines and 2 axial flux machines;
- WP3 concerns the power converter and the regulation, strongly linked to the machine design insofar the constraints applied by the converter must be adapted to the insulation;
- WP4 groups the testing of the samples, coils for example, and the whole machines for performance and reliability evaluation;
- WP5 is original as it concerns the environmental footprint analysis of the machines.

The means requested to achieve the objectives mainly concerns the staff expenses and the cost for manufacturing the designed prototypes. The partners take a specific care in the project organization with milestones placed at the end of important subtasks, essential to validate the prototype production and to evaluate the reliability and the performance.

The project is in accordance with the domain « Sciences de l’énergie et des matériaux » and the axis 2.2 « Une énergie durable, propre, sûre et efficace ». It clearly converges to the goal of increasing the technology in the field of energy, and more specifically the efficiency, the reduction of automobile carbon emission and the improvement of the environmental footprint of e-mobility, in accordance with the issues defined by the energy transition law of 18 august 2015. The consequences in terms of technology transfer may be significant insofar the attempts are obvious in the transport domain, especially from international electrical machine manufacturers. Including a prototype manufacturer in the consortium will create a dynamic of development with end-users.