Design considerations for cost effective Radial Flux Interior Permanent Magnet Motors with increased Demagnetization Robustness

The paper investigates demagnetization effects under three-phase short-circuit conditions, in Radial Flux- Interior Permanent Magnet Motors favored in electric mobility applications. The geometry optimization is based on high efficiency requirement along a wide operating range, in conjunction with high torque in low speed ranges and satisfactory performance under field weakening conditions. Various permanent magnet material grades are considered while three different magnet configurations are studied, namely V-, Insert-, and Spoke-type ones. The robustness under short circuit conditions is investigated by using the Limited Model and Finite Element Analysis. The feasibility analysis is drawn by conveniently assessing advantages and drawbacks among the considered topologies.