Improved EMI Behavioral Modeling Method of Three-Phase Inverter Based on the Noise-Source Phase Alignment

The electromagnetic interference (EMI) behavioral model (BM), including active one-port networks, is widely used to guide the EMI filter design. To build BM, the series and shunt impedance insertion (SSII) based modeling method is normally adopted. During the SSII-based modeling, the time-domain measurements under different impedance insertion cases are introduced. However, the noise-source phases are time-varying, which means that the noise-source phases are different under multiple measurements. The different noise-source phases cause the errors of BM. To address this shortcoming, this article investigates the effect of the noise-source phases on BM for the first time. The improved BM method based on the noise-source phase alignment is proposed. The improved BM method effectively improves the EMI prediction accuracy of BM with an error of 6 dB or less. The effectiveness of the improved modeling method for the conducted emissions estimation is verified in the three-phase inverter test prototype.