This example shows the generation of a temperature profile based on switching and conduction losses in an insulated-gate bipolar transistor (IGBT). There are two buck converters. For one converter, the IGBT attaches to a Foster thermal model. For the other converter, the IGBT attaches to a Cauer thermal model. The parameters for the thermal models are tuned to give roughly equivalent results. At a simulation time of 50ms, the driving frequency changes from 40kHz to 20kHz, which increases the conduction losses and decreases the switching losses. The change in the losses results in a corresponding change in the temperature of the IGBT.
The plot below shows the IGBT temperature and energy loss as functions of time for both the Foster and Cauer thermal models. The power loss is the slope of the energy-loss curve.