针对表插式永磁同步电机转矩脉动较大的问题,提出在永磁体磁极间开辅助槽的方法提升电机性能.分析磁极间开槽的原理,指出在磁极间开槽能够改善气隙磁场分布,减小反电动势中的谐波含量,进而使电机转矩脉动得到抑制.并且磁极间开槽会改变电机的交、直轴电感,使电机的弱磁扩速能力得到提升.利用有限元分析得出最佳开槽形状,并验证开辅助槽能减少反电动势谐波含量并抑制转矩脉动;通过仿真计算电机电感变化,并对比等效直轴去磁状态下电机的气隙磁通密度波形与以不同最高转速时所需的直轴电流,得出开槽后的表插式永磁同步电机更适合用于弱磁扩速.本文所研究的新结构对提升电机性能有一定的指导意义.%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.
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