Modeling and analysis of common mode conducted electromagnetic interference of metro traction inverter

In high power PWM inverter system, EMC problem becomes more and more serious, common mode conducted electromagnetic interference (EMI) becomes the research hotspot. By studying the interference source and interference path of metro traction inverter system, this paper proposes to establish the equivalent model of metro inverter system for the whole circuit. By extracting the high-frequency parasitic parameters of metro inverter system structural parts through simulation software, the whole circuit simulation model is built, and the common mode conducted electromagnetic interference is simulated and measured. At 150KHz-30MHz, the simulated spectrum and the measured spectrum peak value are 92.489dBuA and 94.064dBuA, respectively. The peak error between the simulated spectrum and the measured spectrum is about 1.6dBuA, and there is obvious resonance at 2.1MHz and 2.07MHz, respectively. The simulated spectrum and the measured spectrum peak value and their variation trend are basically the same, the amplitude difference is very small, which proves the correctness of the high-frequency equivalent model and analysis of the whole circuit proposed in this paper. This method can be used as a feasible scheme to calculate and predict common-mode EMI of three-phase metro inverter system.