五相容错永磁同步电机磁动势与转矩研究

MMF and torque of five-phase fault tolerant permanent magnet synchronous motor

为了分析五相容错永磁同步电机开路故障时转矩波动变化的原因,采用绕组函数研究定子磁动势的谐波分布。开路故障未调整时,通过主波磁动势的时空分布揭示了磁动势和转矩之间的关系,并解释转矩增大的主要原因;此时定子磁动势增加了5k和10k±3次谐波,但由于槽谐波幅值下降,转子总损耗减少。对开路故障采取电流控制策略进行调整后,平均转矩增加到正常值,但由于存在二次和四次纹波转矩,转矩波动相对于正常情况仍然较大。同时,定子磁动势10k±1次谐波幅值恢复到正常水平,但10k±3次谐波仍然存在且幅值增加,因而转子损耗相对于正常工作情形增大。

In order to explain the reason of torque change after open-circuit failure for five-phase fault tol- erant permanent magnet synchronous motor （FTPMSM）, the distribution of stator magnetic motive force （MMF） harmonics was investigated by adopting the winding function. Under open-cireuit fault without adjustment, the relationship between MMF and torque was revealed by analyzing the time-space distribu- tion of main harmonic MMF, and the main reason that torque ripple increases after open-circuit fault was explained. Under this situation, the stator MMF appears harmonies of 5k and 10k ＋ 3 orders, but the total eddy-current losses induced by the MMF harmonics decrease because of the amplitude decline of slot har- monics. When the current control strategy is applied to adjust the failure, the average torque can basical- ly increase to the normal value. However, the torque ripple is still larger than normal case, due to the ex- istence of the second and fourth ripple torque. At the same time, the amplitudes of MMF harmonics of lOk ~ 1 order increase to the normal level, whereas the harmonics of lOk ~ 3 order still exist and their amplitudes increase a lot. Therefore, the total rotor losses become larger as compared with the normal condition.