Voltage-dependent capacitors in power electronic multi-domain simulations

Abstract

We discuss multi-domain simulation of power electronic systems where non-linear capacitors have a significant impact on the system behaviour, e.g. employing the MOSFET output capacitor Coss for soft switching or employing nonlinear thermal models in coupled electrical-thermal simulations. It is shown which errors can result from approximating non-linear capacitors with simple linear ones as proposed e.g. for Coss in datasheets. Furthermore a highly efficient implementation of non-linear capacitors in numerical circuit simulators is proposed.