Evaluation of Different Magnet Materials and Skewed Geometries for IPMSM at High Speed

In this paper, an investigation on various permanent magnet materials and rotor geometries for Interior Permanent Magnet Synchronous Motors is presented, to achieve optimal performance both at base speed and in a wide flux-weakening region. The research starts from the updated state of the art, which suggests single V-shape magnets, to obtain a good compromise between performance and industrial interest, and rotor step-skewing. To design, analyze and compare several rotor topologies, two software (FluxMotor and Flux2D) have been used. The results highlight that less performing magnet materials are not convenient, due to the need of greater mass of material to reach the same performance, while a simple three steps skewing, combined with the best choice of rotor geometry, provides a strong reduction of torque ripple, which remains low up to 8000 rpm.