辅助槽对内置式永磁同步电机齿槽转矩的影响

针对齿槽转矩带来的永磁电机转矩波动导致振动和噪声的问题,采用开辅助槽的方法抑制齿槽转矩。分析抑制齿槽转矩的原理,通过改变辅助槽的个数、槽深、槽宽、开槽面积和开槽形状,运用Ansoft Maxwell软件对永磁电机建模,利用有限元分析辅助槽对永磁同步电机齿槽转矩的影响。以一台4极36槽电机为例分析的结果表明:当开2个辅助槽,槽深0.7 mm、槽宽1.2 mm、开槽面积为0.84 mm~2、槽型为矩形槽时,齿槽转矩的削弱效果最明显,比未开槽时的齿槽转矩减小了75.2%;且开辅助槽前后反电动势变化不大,气隙磁密基波幅值降低,5、7次谐波削弱程度显著,波形畸变率下降至17.78%,电机性能得到改善。

Effects of auxiliary slots on the cogging torque of an interior permanent-magnet synchronous motor

Aiming at finding the solution to the problem of vibration and noise resulting from the torque fluctuation of a permanent magnet motor caused by cogging torque, auxiliary slots were used to reduce the cogging torque. The principle of suppressing cogging torque was analyzed and by changing the number, depth, width, slot area and slot shape of the auxiliary slot, Ansoft Maxwell software was used to model the permanent magnet motor, and the finite element method was used to analyze the effect of the auxiliary slot on cogging torque of the permanent magnet synchronous motor. Taking a 4-pole 36-slot motor as an example, the analysis results show that with two auxiliary rectangular slots whose depth, width and area are 0.7 mm, 1.2 mm, and 0.84 mm² respectively, the weakening effect is the most obvious, with the cogging torque 75.2% lower than that without an auxiliary slot. In addition, the back electromotive force changes little before and after the application of the auxiliary slot, and the amplitude of the fundamental wave of the air gap magnetic density decreases; the degree of 5th and 7th harmonic weakening is significant; the waveform distortion rate drops to 17.78%, and the motor performance is improved.