一种分数槽永磁同步电机的转矩计算方法

Torque Calculation Method of Fractional Slot Permanent Magnet Synchronous Motor

为准确计算分数槽永磁同步电机的转矩,建立了一个新的分数槽永磁同步电机的数学模型。通过分析电机的空载反电动势和定子磁链,同时考虑了磁链谐波和d-q轴之间的交叉互感,然后计算出电机的永磁转矩、永磁转矩脉动及磁阻转矩、磁阻转矩脉动,并揭示了转矩脉动产生的机理:永磁转矩脉动主要是6k次谐波,其中永磁转矩脉动中占比最大的为转子磁链与永磁体作用产生的12次谐波转矩。磁阻转矩脉动主要是由定子绕组在d-q轴的6k次自感谐波和交叉互感谐波产生的谐波转矩,其中磁阻转矩脉动中占比最大的为6次d-q轴互感产生的6次谐波转矩。不论是永磁转矩还是磁阻转矩,占比最大的都是由q轴电流产生的谐波转矩。最后验证了模型的正确性。

In order to accurately calculate the torque of the fractional slot permanent magnet synchronous motor,a new mathematical model of the fractional slot permanent magnet synchronous motor is established.By analyzing the no-load back EMF and stator flux linkage of the motor,considering the flux linkage harmonics and the cross-inductance between d-q axis,the permanent magnet torque,permanent magnet torque ripple,reluctance torque,and reluctance torque ripple of the motor are calculated.The mechanism of torque ripple is also revealed:permanent magnet torque ripple is mainly 6k harmonics,the largest proportion of the permanent magnet torque ripple is the 12th harmonic torque generated by the rotor flux linkage and the permanent magnet.The reluctance torque ripple is mainly caused by the 6k self-inductance harmonics and cross mutual inductance harmonics of the stator winding on the d-q axis,the largest proportion of reluctance torque ripple is the 6th harmonic torque generated by the 6th d-q axis mutual inductance.Regardless of permanent magnet torque and reluctance torque,the largest proportion of the 6th harmonic torque is the harmonic torque generated by the q-axis current.Finally,the correctness of the model is verified.