Sustainability Aspects of Electrical Machines for E-Mobility Applications Part I: A Design with Reduced Rare-earth Elements

This paper presents a study on different permanent magnet motor topologies that can be used in e-mobility applications. Considering the environmental effects of rare earth elements used in permanent magnet materials, focus in this paper is placed on the solutions with less rare earth element magnets. Additionally, challenges in using non rare earth magnets in the rotor structure of permanent magnet motors are reviewed and discussed. The risk of demagnetization under short-circuit condition is considered as one of the main challenges in using non rare earth magnets that needs attention when designing the electric propulsion system. As shown in this paper, proper rotor design can significantly improve the risk of demagnetization allowing short-circuit in larger operation range. In addition, obtaining an acceptable level of performance and efficiency as using rare earth elements is possible to achieve.