PSIM v12 features improvements to the Thermal Module to abstract away complexity from the schematic. The thermal Cauer/Foster model to get from the junction to the device case is now part of the device. Also, you do not need to place ammeters to record the individual conduction and switching losses, you simply toggle flags.
This video shows the improvements and shows the new models in action with a totem pole PFC example circuit using GaN devices from GaN systems. The Thermal module allows you to simulate switching and conduction losses for active and passive switches: diode, MOSFET, IGBT. The Thermal module also allows for inductor core and winding losses to be simulated.