Modeling and analysis of common mode conducted EMI in three phase inverter

It is necessary to research the modeling and analysis method of the conducted electromagnetic interference(EMI) in a three-phase inverter for the purpose of predicting and suppressing its common mode(CM) conducted EMI.In this paper,based on an analysis of the switching sequence and conducting states of the switching devices of the inverter,a simple and convenient equivalent circuit model of the inverter is proposed consisting of the models of its CM conducted EMI noise sources and their propagation path.The high frequency parameters of the model are obtained by measurement and electromagnetic field numerical calculation.Simulations using the proposed model and an experiment have been conducted on a three-phase inverter system.The experimental and simulation results of the EMI spectrum match with each other over the frequency range from 150 kHz to 30MHz,which demonstrates that the proposed model is valid and effective.This analysis method can be used to evaluate the CM conducted EMI in three-phase inverter systems.