Study of techniques for reducing the cogging torque in permanent magnet motors

In order to reduce the cogging torque, many methods have been advised and studied in permanent magnet(PM) motor. In this paper, the methods of pole arc coefficient of PM, armature teeth notching, PM shifting and different pole arc coefficient combination are studied and improved based on the analytical expression of cogging torque derived in this paper, and the methods to decide the design parameters are given. At last, the calculation results by finite element method verify that the cogging torque can be greatly reduced by these improved methods.