(1.State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Tianjin 300130, China;2.Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Tianjin  300130, China; 3.School of Electrical Engineering, Hebei University of Technology, Tianjin 300130, China)


Abstract: Aiming at the problems of high vibration and noise caused by high cogging torque in hybrid excited doubly salient permanent magnet machine, the method of using auxiliary slots on the top of 12/10 hybrid excited switching flux permanent magnet (HESFPM) machine was investigated. The topology and operation principle of 12/10 HESFPM machine were introduced. Based on the cogging torque expression of 12/10 HESFPM machine, the reasons for the reduction of cogging torque by using auxiliary slot on the top of rotor were explained. By using finite element analysis, the influence of the shape, spacing and size of auxiliary slots on the cogging torque were investigated. Based on the optimization of the auxiliary slot structure, the cogging torque of 12/10 HESFPM machine with different auxiliary slot structures were compared, and the auxiliary slot structure which can mostly reduce the cogging torque was obtained. Finally, the influence of auxiliary slots on the back-EMF and average torque of machine were presented. The results indicate that if two rectangular auxiliary slots on the top of rotor are used, the cogging torque of 12/10 HESFPM machine can be reduced by 92.32% at the expense of 10.3% reduction of average torque.
Key words: hybrid excited switching flux permanent magnet (HESFPM) machine; cogging torque; auxiliary slots