Optimization and Analysis of Cogging Torque of Permanent Magnet Spherical Motor

Compared with the general multi-degree-of-freedom motor, the permanent magnet spherical motor has the advantages of simple structure, convenient control and small size. This paper analyzes the cogging torque of a surface-mounted spherical permanent magnet motor (SSPMM) with an 8-pole, 12-slot three-layer stator. The SSPMM has two kinds direction of cogging torque: rotation direction and deflection direction. In order to weaken the multi-directional cogging torque, a new auxiliary slot shape was proposed. Through theoretical analysis and finite element simulation, the FEA is compared with the analytical results to verify the accuracy of the method. It is verified that the research method can effectively reduce the cogging torque amplitude in two directions.