关键词: 永磁同步电动机, 齿槽转矩, 槽口偏移, 有限元法

Abstract:

The cogging torque is one of the key problems that must be taken into consideration in the design and manufacture of permanent magnet machines. In order to reduce cogging torque of permanent magnet synchronous motor, the cogging torque was analyzed by Fourier series method, and the relationship between the total cogging torque and the single slot cogging torque was studied. The armature slots along the direction of rotation was divided into groups in even number. The cogging torque in a group was analyzed and deduced, setting adjacent armature slot groups as corresponding groups. By the method of making single or several armature slot groups shifting appropriate angles, the magnitude component of the cogging torque between the corresponding groups was counteracted. Thus, the specific harmonic amplitude of cogging torque for the corresponding groups was reduced, and the amplitude of the total cogging torque was weakened. The formula of specific angle of armature slot groups shifting was given. Taking a permanent magnet synchronous motor with 12 slots 8 poles as an example, through the simulation analysis, the results show that, the proposed method can effectively reduce the amplitude of fundamental harmonic and low-order harmonic of total cogging torque, and the amplitude of cogging torque was also decreased.

Key words: permanent magnet synchronous motor, cogging torque, slot shifting, finite element method