基于场路耦合的永磁电机高频径向电磁力波分析

High Frequency Radial Electromagnetic Force Wave Analysis of Permanent Magnet Motor Based on Field-Circuit Coupling

振动和噪声的大小是衡量家用变频空调压缩机品质的指标之一。针对家用变频空调压缩机出现的高频噪声问题,以一台6极9槽家用空调压缩机用永磁同步电机及其控制系统为研究对象,基于场路耦合法,对常规空间矢量脉宽调制(SVPWM)技术及其控制策略所引入的谐波电流成分与高频声振响应特性进行研究。首先通过解析法分析了永磁电机高频噪声源的产生机理。其次从原理上阐述了电流谐波对径向电磁力波的阶次特征与频率特性的影响。然后建立了永磁电机的场路耦合模型,详细分析了不同负载工况下高频径向电磁力波频率与开关频率的关系。最后采用声振特性试验进行了验证,结果表明:场路耦合模型可以考虑电机本体、控制策略以及开关频率等非线性因素引起的高频电流谐波影响,并得出了高频径向电磁力波频率与载波频率的关系式,为永磁电机的高频噪声预测以及减振降噪提供了参考。

The magnitude of vibration and noise is one of the indexes to measure the quality of household variable frequency air conditioning compressor.In order to solve the problem of high frequency noise of the household variable frequency air conditioning compressor,a permanent magnet synchronous motor with 6-pole 9-slot for household air conditioning compressor and its control system are used as the research objects.Based on the field-circuit coupling method,the harmonic current components and high frequency acoustic vibration response characteristics introduced by conventional space vector pulse width modulation(SVPWM)technology and its control strategy are studied.Firstly,the generation mechanism of high frequency noise source of permanent magnet motor is analyzed by analytic method.Secondly,the effect of current harmonics on the order and frequency characteristics of radial electromagnetic force wave is described in principle.Then,the field-circuit coupling model of permanent magnet motor is established,and the relationship between high frequency radial electromagnetic force wave frequency and switching frequency under different load conditions is analyzed in detail.Finally,the acoustic vibration characteristic test is used to verify the results.The results show that the field-circuit coupling model can consider the high frequency harmonic current caused by nonlinear factors such as motor body,control strategy and switching frequency,and relationship of the high frequency radial electromagnetic force wave frequency and the carrier frequency is obtained,which provides reference for high frequency noise prediction and vibration and noise reduction of permanent magnet motor.