Prediction of common mode conducted EMI in single phase PWM inverter

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. Time and frequency domain analysis is conducted to obtain CM current waveforms and noise spectra in 10 kHz-30 MHz frequencies. The simulated CM EMI waveforms are compared with the actual experiments to verify the validity of the proposed model.