Prediction Model of Conducted Common-Mode EMI in PWM Motor Drive System

The conducted common-mode EMI of PWM motor drive system has enhanced systematic radiated interference because its circulating path includes the earth. At the same time it also brings conducted interference to other electrical system in the form of interference current and brings negative effects. In order to predict the conducted common-mode EMI, based on deep research of the interference source and coupling route, each part high-frequency equivalent model of PWM motor drive system is built which including non-ideal characteristic of passive components and parasitic characteristic of coupling route. This equivalent model can be used to analyze and predict common-mode EMI emission intensity and common-mode EMI current at motor side in PWM motor drive system. The consistency of simulation and experimental result is good.