优化隔磁桥对永磁同步电机输出转矩的影响

转子分段斜极能有效降低永磁同步电机(PMSM)转矩脉动，但会使电机平均输出转矩降低。为了解决这一问题，在转子分段斜极的基础上优化隔磁桥提高平均输出转矩。分析了转子分段斜极对电机齿槽转矩、空载反电动势、转矩脉动和平均输出转矩的影响，选取出最优的转子分段数和斜极角。在转子分3段，斜极角为5°的基础上，以保持转矩脉动不变为前提，通过优化转子参数H₍R_ib)和D_min找到最优的隔磁桥结构，平均输出转矩由138.5 N·m提升到147.2 N·m,说明所提方法的有效性。优化后齿槽转矩峰值由0.24 N·m降低到0.18 N·m,空载反电动势基波幅值由278.7 V提升到288.6 V且谐波畸变率基本不变，说明隔磁桥优化后能提高电机的其他性能。

Influence of Optimized Magnetic Isolation Bridge on Output Torque of Permanent Magnet Synchronous Motor

The rotor step skewing can effectively reduce the torque ripple of the permanent magnet synchronous motor (PMSM), but it will decrease the average output torque of the motor. In order to solve this problem, the magnetic isolation bridge is optimized on the basis of the rotor step skewing to improve the average output torque. Firstly, the influence of the rotor step skewing on the cogging torque, no-load back electromotive force (EMF), torque ripple and average output torque of the motor is analyzed, and the optimal number of rotor segments and step skewing angle are selected. The segments is 3, the step skewing angle is 5°, the torque ripple keeps unchanged. Under these conditions, the optimal magnetic isolation bridge structure is found by optimizing the rotor parameters HRib and Dmin, and the average output torque increases from 138.5 N·m to 147.2 N·m. The effectiveness of the method is verified. Meanwhile, the peak value of cogging torque decreases from 0.24 N·m to 0.18 N·m, the amplitude of no-load back EMF fundamental wave increases from 278.7 V to 288.6 V, and the harmonic distortion rate is nearly unchanged. The results indicate that other performances of the motor can be improved after optimization of the magnetic isolation bridge.