PWM逆变器共模传导电磁干扰的预测

PREDICTION OF COMMON MODE CONDUCTED EMI IN PWM INVERTER

在PWM逆变器系统中,IGBT的高速开关动作会产生很高的dv/dt、di/dt,导致严重的电磁干扰。对PWM逆变器共模传导电磁干扰的机理进行研究,得出了共模传导干扰源和传播途径。通过与buck变换器进行对比,提出了一种用于研究PWM逆变器共模传导干扰的等效电路,利用实验测得等效电路中无源器件的参数及对等效电路的电压源进行傅立叶变换,在10KHz-30MHz频段进行了频域分析,计算的共模传导干扰频谱与实验结果进行对比基本一致,证明文中提出的共模传导干扰等效电路模型及其分析的正确性。

In PWM inverter system, the high dv/dt and di/dt due to the fast switching of IGBT could bring serious EMI issues. Based on the study of mechanisms on common mode conducted electromagnetic interference (CM EMI) associated with a single phase PWM inverter, the origin and propagation path of CM EMI noise are highlighted. Compared with buck converter, a simple equivalent circuit is proposed to study the CM EMI. The parameters of passive element are measured by experiment and Fourier transform of the voltage source in equivalent circuit is performed. Frequency domain analysis is used to rapidly obtain the noise spectra in 10KHz-30MHz frequencies. The simulated CM EMI spectra are compared with the actual experiments to verify the validity of the proposed model.