A Method for Optimizing Performance of Inset Permanent Magnet Motor

作者:Bao, Xiaohua*; Wu, Changjiang; Hu, Yunpeng; Wang, Chunyu
来源:Transactions of China Electrotechnical Society, 2018, 33(2): 238-244.
DOI:10.19595/j.cnki.1000-6753.tces.L70358

摘要

Because of the large torque ripple of inset permanent magnet synchronous motor (PMSM), a method of notching auxiliary slots between adjacent permanent magnets is proposed to improve the performance of PMSM. The principle of notching auxiliary slots is analyzed. The auxiliary slots between poles can improve the distribution of air-gap flux density and reduce the harmonic content of back EMF, thus, the torque ripple can be suppressed. The auxiliary slots between the poles will change quadrature-axis and direct-axis inductance of the motor, accordingly its ability of flux-weakening will be improved. Finite element analysis (FEA) is used to acquire the best slot shape. It is verified the auxiliary slots can reduce the harmonics of back EMF and restrain the torque ripple. The motor inductances are calculated by FEA. The air gap flux densities of different rotor structures are compared under equivalent demagnetization status and d-axis current at different maximum speed. It is shown that the inset PMSM with auxiliary slots is more suitable for speed control of flux-weakening. The new proposed structure will provide a certain reference value for improving the performance of motor.