A Method of Reducing Air-Gap Harmonic of Permanent Magnet Motor for Fitness Car

Abstract

In order to solve the high harmonic content of permanent magnet synchronous motor (PMSM) for fitness car, a PMSM with built-in permanent magnet bridge is proposed in this paper. Compared with surface mounted permanent magnet synchronous motor (SM-PMSM), the proposed motor with permanent magnet bridge structure has lower harmonic content. The performance and magnetization angle of the proposed motor are compared and analyzed in detail. The results obtained from finite element analysis show that the permanent magnet bridge can increase the air gap magnetic field intensity, and different directions of magnetization will affect the amplitude of fundamental wave of air gap magnetic density. Moreover, it can reduce the total harmonic distortion (THD) and make the magnetic density waveform more sinusoidal. It is very beneficial to the smooth output of torque of fitness car.