Stray inductance estimation with detailed model of the IGBT module

Abstract

Stray inductances cause various problems in a power inverter and should be appraised and minimized at an early design stage to avoid later required countermeasures and redesign after the device prototype has been built. The stray inductances of the commutation loops of an Active Neutral Point Clamped (ANPC) inverter are estimated in this paper. Detailed model of the Insulated Gate Bipolar Transistor (IGBT) module is created to improve the accuracy of the stray inductance calculation. The influence of the coupling between the IGBT modules and between the IGBT modules and the busbars on the commutation loop inductance is considered. The partial inductances of the components of the commutation loops are estimated by AnSYS Q3D parasitic extractor to calculate the total stray inductance. It is found that the commutation loop inductances of the studied ANPC inverter are overestimated by neglecting the couplings between the IGBT modules and between the IGBT modules and the busbars.