An improved SiC-MOSFET model with focus on internal stray inductance and body diode stored charge for switching transients

Accurate switching transients modelling is important for SiC power converter layout optimisation. A SiC-MOSFET manufacturer model is used as a reference. Although the manufacturer model correctly represents device output and capacitance characteristics, there are discrepancies between modelled switching transients and experiment results. To improve the model, we propose a method to accurately model stored charge and use Ansys Q3D to model stray inductance inside device packaging. As a result, the model has been improved by 70% regarding VGS oscillation amplitude and 50% regarding current overshoot and overall transient behaviour in di/dt and dv/dt.