Design Considerations of Magnet Configurations in Interior Permanent Magnet Machines for High-Speed Traction Applications: A Comprehensive Study

This article presents a comprehensive comparison and the design considerations of three magnet configurations in interior permanent magnet (IPM) machines for high-speed traction applications. The study investigates single-V, double-V, and single-U magnet configurations. A multiphysic multiobjective optimization is used to enhance the three machines, which are designed with a constraint to fit in the same housing and have the same torque-speed curve. The optimized configurations are then compared with respect to multiple performance indices according to common design criteria for traction motors, including no-load characteristics, short circuit characteristics, demagnetization, torque, efficiency, loss distributions, continuous performance, and magnet volume. The study presents how multiphysics design requirements affect the selection of magnet configurations: a single-V rotor configuration can be selected to have the lowest magnet usage as well as high torque density; while the double-V design is suitable for noise-sensitive, high-efficiency applications but requires a rotor-cooling system; and the single-U design is a good candidate for managing tradeoffs among the other options while maintaining a high degree of freedom in the design.