Model of EMI coupling paths for an off-line power converter

Study on the characteristics of the EMI coupling paths in power electronics equipment is helpful to analyze the EMI mechanism and improve its EMC performance. In this paper, based on the analysis of the EMI sources and coupling paths of an off-line PWM converter, a high frequency model of EMI coupling paths is built and verified by testing and simulating. The qualitative analysis about resonance phenomenon in high frequency band is introduced by simulation. By Monte Carlo simulation method, it is found that the parameter fluctuation mainly influences the amplitude of coupling paths in conducted frequency band. The simplified common mode model of coupling paths is also deduced and its characteristics are mainly influenced by those biggish stray parameters.