Using Zth matrix model for more accurate Tvj calculation for IGBT power modules

Inhalt:
Thermal modelling of IGBT power modules is often done by considering only the transient ther-mal impedance Zth of each chip individually, and mostly the thermal cross-coupling effects is ne-glected. This may cause inaccuracies in junction temperature calculations or lifetime estimations. In this paper an advanced thermal model is pro-posed, which can combine the self-heating effects and all cross-coupling effects together in one Zth matrix. And the basic description and extraction of the Zth matrix model characteristics by FEM (Fi-nite Element Method) simulation is introduced. Then the Zth matrix model is built-up in PLECS software, and verified by the FEM simulations on transient power profiles. Finally, the improve-ments of Tvj calculation with Zth matrix model for wind application is discussed and summarized.