Currently this model uses both Power Module blocks with a Sub-Cycle Average implementation for AC side I, and Averaged models for AC side II. In order to do loss modeling, you will need to replace the power semiconductors in that model with our standard IGBT/Diodes components from our library. Have you looked at any of our demo models that use the thermal modeling features of PLECS? There are none currently for multilevel converters, but you can certainly build this. How many power levels are you looking for?