Research on Common-mode EMI of Differential-mode Characteristic Frequency

The EMI generated by power electronics equipment is a research hotspot of EMC.Accurately identifying the type and mechanism of EMI is the premise of the corresponding suppression,which is one of the difficulties.A 12-phase rectifier generator system is studied.The equivalent circuit and the conducted interference characteristic of 12-phase recti-fier system are analyzed.According to the analysis,the dissymmetry of power supply network will result in the conversion from Differential-Mode(DM) EMI into Common-Mode(CM) EMI.This kind of non-intrinsical CM EMI is often more serious than the intrinsical CM EMI.The results are also verified by experiments.The research achievements can be applied into the design of EMI filter for power electronics equipment.