Non-linear Modeling of High-Frequency Differential-Mode Conducted EMI Emissions in Single-Phase Inverter

Abstract

Wide-band-gap switching power devices, such as SiC MOSFETs, are preferred for high-voltage power converters due to their low switching losses compared to Si-based devices. However, their operation with high di/dt and dv/dt during switching exacerbate the issue of electromagnetic interference (EMI), particularly in the high-frequency region. To predict conducted EMI emissions, frequency-domain behavioral models are used. However, they require time-domain measurements on experimental prototypes. In this paper, we present a non-linear model for predicting high-frequency differential-mode conducted emissions (DM-CE) on the input side of a single-phase inverter. The modeling of DM-CE depends on circuit switching transients and the parasitics of the noise propagation path. An empirical non-linear model for SiC MOSFET parasitic capacitance and transfer characteristics is presented. The switching transients of a single-phase inverter were simulated using the proposed SiC MOSFET model and circuit wiring parasitics. DM-CE is calculated from the circuit simulations and compared with experimental observations.