Analysis and Integration of Chaotic Gaussian PWM and Passive Filter for Conducted EMI Suppression

Abstract

As wide bandgap semiconductor devices continue to be adopted, power converters can now operate at higher switching frequencies and power densities. However, this progress presents new challenges in controlling electromagnetic interference (EMI). Traditional passive EMI filters (PEFs) effectively suppress EMI, but are constrained by their size and weight, limiting power density improvements in converters. To address these issues, this article introduces an innovative strategy combining chaotic pulsewidth modulation (PWM) with Gaussian waveforms to produce chaotic Gaussian PWM (CGPWM). While CGPWM demonstrates excellent performance in reducing high-frequency EMI, stringent electromagnetic compatibility standards still necessitate the use of robust passive filters. Accordingly, this article designs a PEF based on CGPWM, aimed at enhancing EMI suppression while significantly reducing the size and inductance of common-mode (CM) inductors. By examining the spectrum reduction effects of square, Gaussian, and chaotic Gaussian waveforms, an optimized PEF is developed based on CGPWM. Experimental results reveal that this integrated approach reduces CM inductor volume by over 74.28% and inductance by 60%, achieving up to 50 dB of EMI attenuation. These outcomes highlight the potential of combining CGPWM and PEF for effective EMI suppression and minimized filter size, making it a promising solution for high-density power electronics.