Lumped Dynamic Electrothermal Model of IGBT Module of Inverters

This paper presents a lumped dynamic electrothermal model of an insulated gate bipolar transistor module of inverters. The thermal model consists of a 3-D network of RC cells constructed for time-dependent operation. The network was found to be precise for determining the temperature excursion of diodes and transistors subsequent to time-dependent power losses. Thermal resistances and capacitances accounting for heat spreading and thermal penetration depth effects were introduced. Electrothermal simulations carried out on a 1200 V-300 A module with a time-dependent average power loss were found to be in good agreement with experiments using infrared thermal imaging. This paper focuses on very-low-frequency behavior (less than 1 Hz) at a switching frequency of 10 kHz.