Cogging torque reduction based on segmented skewing magnetic poles with different combinations of pole‐arc coefficients in surface‐mounted permanent magnet synchronous motors

Abstract

The calculation and reduction of cogging torque are fundamental to the evaluation and optimisation of motor performance. Considering that the accuracy of the cogging torque calculated by analytical method (AM) is low, an accurate calculation model of the effective air-gap length considering the actual stator slot structure and suitable for any motor is proposed, the cogging torque of 6p36s surface-mounted permanent magnet synchronous motor (SPMSM) are calculated accurately and verified by finite element method (FEM). Furthermore, the segmented skewing magnetic poles with different combinations of pole-arc coefficients are designed to weaken cogging torque, and the optimal combination of pole-arc coefficients and tilting angle of the adjacent magnetic poles are summarised by AM and particle swarm optimisation (PSO) algorithm. Finally, the cogging torques of six SPMSMs with different slot-pole combinations including 6p36s, 4p36s, 6p9s, 8p9s, 8p12s and 10p12s are analysed, and the results indicate that the cogging torque can be greatly weakened based on segmented skewing magnetic poles with different combinations of pole-arc coefficients, and other performances of the motors are basically not affected.