Analysis on CM-EMI of Z-source inverter driving motor system of electric vehicle

Motor drive system is a key component in the operation of electric vehicles (EVs). The Z-source inverter in the system will produce large dv/dt and di/dt in the vehicle circuit, which will bring serious electromagnetic interference (EMI) problem to the whole vehicle. This paper fully analyzes the structure and working principle of Z-source inverter, and secondly establishes the common-mode electromagnetic interference (CM-EMI) equivalent circuit composed of Z-source inverter and propagation channel model as well as analyzes and theoretically calculates the CM voltage and CM current, the correctness of the CM-EMI produced by Z-source inverter as well as the theoretical calculation results are proved by Matlab/Simulink simulation and experimental verification. The spectrum characteristics are obtained by fast fourier transformation (FFT) transform, and the CM-EMI is simulated and measured, thus the simulation results are in good agreement with the measured spectrum in the frequency range of 0.15∼30MHz, prov-ing that the CM equivalent circuit model established by this method is feasible.