Modeling-based examination of conducted EMI emissions from hard- and soft-switching PWM inverters

For the study of electromagnetic interference (EMI) mechanisms in pulsewidt h-modulated inverters, this paper presents an analysis approach based on em pirical models of the inverter components and their associated various para sitics. The power switching devices were modeled with a physics-based devic e modeling technique. Using time-domain reflectometry, we characterized the major parasitics in the device modules, passive components, cables, leads, and interconnects. Simulations of a full-bridge insulated gate bipolar tra nsistor inverter were then carried out in the time domain under hard-switch ing and zero-voltage switching conditions. The simulated EMI spectra were c ompared with the experimental counterparts with the separation of common-mo de and differential-mode EMI The comparisons verified the validity of the p roposed modeling approach over most of the EMI frequency range. Also discus sed in the paper are the soft-switching effects on the inverter's EMI.