Output DM EMI Noise Prediction for MHz TCM-Based Single Phase Inverter

Conventional fast Fourier transform analysis is limited in conducted electromagnetic interference (EMI) prediction for triangle current mode (TCM) based converters. Several prediction strategies based on EMI receiver modeling have been published for this issue, but the prediction range was below 1 MHz. Such a narrow frequency range cannot meet the demands of EMI prediction for MHz converter. In this article, a more accurate differential mode (DM) EMI prediction is proposed for MHz TCM-based single-phase inverter. The accurate drain-to-source voltage model considering the TCM resonant transition is established for different TCM-derived strategies at first. Passive components of the propagation path are also modeled with the measured impedance for more accurate transfer gain. An improved envelope detector model of the EMI receiver is proposed for an accurate quasi-peak spectrum. The prediction range can be extended to 5 MHz. Moreover, the EMI of TCM, hybrid triangle current mode, and sinusoidal triangle current mode are analyzed and compared with the established prediction strategy. The worst spectrum can be determined, and the DM filter can be designed without repetitive measurements. Finally, A 500 W MHz single-phase inverter prototype is built, and the evaluation of the measured conducted EMI spectrum and the EMI filter design can verify the theoretical analysis.