Research on cogging torque reduction method for permanent magnet synchronous motor accounting for the magnetic pole edge effect

Abstract

Due to the existence of the magnetic pole edge effect, the actual cogging torque of the existing segmented step skew motor does not reach the theoretical minimum. Thus, a method for suppressing cogging torque of permanent magnet synchronous motor considering the magnetic pole edge effect is proposed. The magnetic pole edge effect is creatively converted into the amplitude and phase offset of the cogging torque generated by each pole segment. On this basis, an optimization problem is constructed in which the fundamental component of cogging torque is zero and the total harmonics is minimum. The optimal magnetic pole length and skew angle parameters of each segment are obtained by solving the optimization problem quantitatively. The results can provide theoretical guidance for motor design, which can minimize the cogging torque of step skew structures. The effectiveness of the proposed method in weakening the cogging torque of the step skew motor is demonstrated by theoretical calculation, 3D finite element analysis, and experimental results.