三相PWM变换器传导干扰的预测分析

Forecast of conducted interference of three-phase PWM drive motor system

为了预测整流-逆变-感应电机系统的传导干扰,建立系统的共模和差模等效电路。等效电路由干扰源和耦合通道构成,用干扰源的数学模型代替电力电子器件开关时的非线性环节,对整流桥产生的共模和差模干扰采用傅里叶变换得出共模和差模干扰源的表达式,对逆变桥产生的共模和差模干扰采用双重傅里叶积分法得出干扰源的表达式,根据共模和差模传播路径的不同给出耦合通道相应的高频模型,根据整流桥和逆变桥各自产生的共、差模干扰源以及共、差模传播通道的高频模型构成的共模和差模等效电路,采用叠加原理得出整个系统的共模和差模干扰。仿真和实验结果验证了等效电路的正确性,建立干扰源和耦合通道频域模型的方法适用于整流-逆变-感应电机系统传导干扰的定量预测分析。

With the object of rectification-inversion motor system,Common mode equivalent circuit and differential mode equivalent circuit are founded to predict interference in this paper.Equivalent circuit is composed of interference source and coupling path.Nonlinear part of power electronic device is replaced by noise source math models.Noise source math models of rectifier and inverter should be calculated separately.For noise source from rectifier,the expressions about common mode and differential mode can be attained by applying Fourier transform.For noise source from inverter,double Fourier integral transform can be applied.Based on common mode and differential mode respectively,the corresponding high frequency models of coupling path were created.Based on superposition theory,common mode interference and differential mode interference of the whole system were educed by equivalent circuit.The simulation and experiment results demonstrate that equivalent circuits are valid.Quantity prediction analysis of conducted interference is realized first to rectification-inversion motor system.