EMI mitigation in switching power converters combining closed‐loop gate drive and chaotic frequency modulation technique

Abstract

All switching power converters are characterised by inevitable switching actions with relevant interference emissions. The voltage and current transients of power metal oxide semiconductor field effect transistor (MOSFET)/insulated-gate bipolar transistor are the main sources in switching power converters for both conducted and radiated emissions. In this study, a promising electromagnetic interference (EMI) mitigation method combining the closed-loop gate drive method and the chaotic switching frequency modulation technique is demonstrated for switching power converters. A chaotic pulse-width modulation waveform with Gaussian S-shape switching transients was proposed to achieve remarkable reduced EMI generation at all frequencies. Spectral characteristics of this new switching waveform were investigated by the power spectral density to verify the feasibility of reduced EMI generation. A closed-loop gate controller was presented to shape the switching transients of power MOSFET into the proposed switching waveform. Circuit tests were carried out in both simulations and experiments. The results validated that the proposed method could achieve remarkable EMI mitigation in switching power converters.