基于谐波分析的永磁电机齿槽转矩抑制

Reduction of Cogging Torque of Permanent Magnet Machines Based on Harmonic Analysis

齿槽转矩是永磁电机特有的问题之一,也是设计制造过程中必须考虑的关键问题。为抑制电机的齿槽转矩,采用解析法与有限元法相结合的方式,研究了一种开辅助槽抑制电机齿槽转矩的方法。运用傅里叶级数对电机的齿槽转矩进行谐波分析,得到齿槽转矩的基波以及各次谐波的大小;将开辅助槽电机的齿槽转矩简化看作辅助槽与磁钢产生的齿槽转矩与原有电机的齿槽转矩的叠加,利用解析法确定辅助槽的开槽位置,使得特定位置的辅助槽与磁钢产生的齿槽转矩的谐波分量与电机原有的齿槽转矩的特定的谐波分量互相抵消,从而抑制齿槽转矩的基波以及低次数谐波分量,使得齿槽转矩幅值下降,并给出了具体的辅助槽位置公式。结合有限元方法,采用与普通槽相等的槽口宽度,并对辅助槽的深度进行仿真分析,得到最优的辅助槽深度。仿真结果表明,在特定的位置上开特定个数的辅助槽,能对齿槽转矩的基波与低次数谐波起到明显的削弱作用,降低齿槽转矩幅值。

Cogging torque is one of the special problems of permanent magnet machines,which is also a key problem to be considered in the process of design and manufacture. In order to reduce the cogging torque of motor,a method of opening the auxiliary slots was presented to reduce the cogging torque of the motor by means of the combination of analytical method and finite element method. Fourier series was used to analyze the cogging torque of the motor,the magnitude of fundamental harmonic and each harmonic were obtained. The cogging torque of the motor was simplified as the superposition of the torque between the cogging torque for auxiliary slots and cogging torque for original motor. The slot position of the auxiliary slots was determined by the analytical method. The harmonic component of the cogging torque of auxiliary slots in the special position was counteracted with the specific harmonic component of the original cogging torque of the motor. Thus,the fundamental and low harmonic components of the cogging torque were suppressed and the amplitude of cogging torque decreased. The location formula of auxiliary slots was also given. Combined with the finite element method,the depth of the auxiliary slots was simulated and analyzed so that optimum depth of the auxiliary slots was obtained,which the auxiliary slot width was equal to the ordinary slots. The simulation results show that,the auxiliary slots with a certain number in the particular position can reduce the fundamental and low harmonic of the cogging torque and the amplitude of cogging torque.