Torque Ripple and Electromagnetic Vibration of Permanent Magnet Synchronous Motor Using Unequal Width of Magnets

In the electromagnetic design phase of permanent magnet synchronous motors(PMSM), reducing cogging torque is as important as improving motor efficiency. In this paper, the electromagnetic performance of SPM motors with unequal pole width is analyzed and calculated in detail. The SPM motor with unequal pole width adopts the method of changing the polar arc coefficient, that is, except for one magnetic pole that is wider, the width of the other magnetic poles is the same. Maxwell’s tensor method is used to explain the mechanism of inhibiting cogging torque, and derives the expression of cogging torque when changing the polar arc coefficient under the condition that the amount of permanent magnet is not changed, and the determination method of polar arc coefficient is given, and the multi-objective optimization strategy of finite element simulation is used to obtain the best parameters, and the torque ripple and electromagnetic vibration can also be suppressed. The simulation results show that the given polar arc coefficient determination method can effectively weaken the cogging torque, torque ripple and electromagnetic vibration of the SPM, and verify the theoretical analysis.