Research of cogging torque reduction by different slot width pairing permanent magnet motors

Cogging torque is one of the main concerns of permanent magnet motor. In this paper, analytical analysis is used to analyze the cogging torque when different slot width pairing method is adopted. The effect of slot width pairing on cogging torque is studied, and some conclusions are drawn. If the least integer n, which makes (nz/2)/(2p) be an integer, is an even number, the cogging torque can be greatly reduced by different slot width pairing, and the method to calculate the width of slot is deduced in this paper. On the contrary, if the least n is an odd number, different slot width pairing method is not effective in reducing cogging torque. The correctness of the above conclusions is verified by finite element analysis of cogging torque.