Performance comparison between Rare earth and Non-Rare Earth based SPM machines using High Silicon Steel

Rare earth magnet materials are widely used in many permanent magnet machines due to their attractive high magnetic strength. High-grade heavy rare earth magnets are typically expensive since their supply is limited and isolated. Alternative choices include utilization of non-rare earth permanent magnets at the cost of performance. This paper compares the performance of an SPM machine for a traction application with a heavy rare earth and a non-rare earth permanent magnets. The choice of JFE Super Core steel materials intended to improve the efficiency at high speed. Both designs were optimized using a Multiphysics scheme accounting for electromagnetic, thermal, and structural physics. The comparative study shows that the non-rare earth based design offers an acceptable torque/power density, while demonstrating attractive field weakening capability and high efficiency with 40% cost reduction relative to heavy rare earth based design. The study demonstrates that the non-rare earth based design using Super Core steels can be an alternative option for applications which are cost and efficiency sensitive.