Analysis of Common-mode EMI in Multi-converter Systems with EMI filters

The DC power system with multiple converters is widely used in multi-electric aircraft, which complicates the analysis of conducted electromagnetic interference (EMI). Although EMI filters are currently the most effective method for suppressing conducted EMI, the interaction influence among multiple EMI filters has not been studied yet, seriously threatening the electromagnetic safety of multi-converter systems. Firstly, based on the behavioral model, this paper proposes a general analysis method for common-mode (CM) EMI in the multi-converter system. Then, based on this method, the influence of the interaction between EMI filters on the suppression performance of multi-converter system containing distributed EMI filters is analyzed. It is found that the EMI filter with high cut-off frequency will weaken the performance of other filters with low cut-off frequency under some frequencies. Finally, the behavior frequency-domain model is compared with the time-domain model in simulation, and shows good consistency.