带式输送机用永磁电机齿槽转矩优化分析

Optimization Analysis of Cogging Torque of Permanent Magnet Motor for Belt Conveyor

摘要: 齿槽转矩会对电机产生噪声、振动等影响，降低电机控制精度。为了保障带式输送机系统整体运行的安全性和平稳性，本文以11 kW表贴式带式输送机用永磁直驱电机作为研究对象，基于能量法分析了齿槽转矩的产生机理，研究了磁体极弧系数、不等厚磁体以及磁体直极偏移对齿槽转矩的影响，通过多目标优化得出最优设计方案，并对优化后样机的反电动势波形及谐波含量进行分析。结果发现，齿槽转矩随极弧系数呈周期性变化；合理选择不等厚磁体的偏心距可以降低气隙磁密高次谐波分量，改善气隙磁密波形，从而有效地削弱齿槽转矩；磁体直极偏移对降低齿槽转矩影响很大，齿槽转矩随分段数的变化受齿槽转矩波形影响，当磁体分2段时，齿槽转矩得到了明显的削弱；通过样机试验得出磁极参数优化能有效降低反电动势谐波含量，降低齿槽转矩，优化电机综合工作性能。

Abstract: Cogging torque will affect the noise and vibration of the motor and reduce the control accuracy of the motor. In order to ensure the safety and stability of the overall operation of the belt conveyor system, this work takes the permanent magnet direct-drive motor for 11 kW surface-mounted belt conveyor as research object. The generation mechanism of the cogging torque has been analyzed using energy method. The influences of the pole arc coefficient, unequal thickness and straight pole offset of the magnets on the cogging torque have been investigated. The optimal design scheme is obtained through multi-objective optimization. The back electromotive force (EMF) waveform and harmonic content of the optimized prototype have been explored. The results show that the cogging torque varies periodically with the pole arc coefficient. Properly selecting the eccentricity of the unequal-thickness magnet can reduce the higher-order harmonic components of air-gap flux density, improve the waveform of air-gap flux density, and effectively weaken the cogging torque. The straight pole offset of the magnet has a significant impact on reducing cogging torque. The variation of cogging torque with the number of segments is influenced by the waveform of cogging torque. When the magnet is divided into two segments, the cogging torque is significantly reduced. Prototype tests have shown that optimizing the magnetic pole parameters can effectively reduce the harmonic content of the back EMF, reduce cogging torque, and optimize the working performance of the motor.