Different Zth model influence on discrete IGBT Tvj calculation in main inverter application

Abstract:
In the main inverter of xEV application, there is relatively little research and paper on IGBT discrete thermal resistance network modeling and the virtual junction temperature calculation. To address this gap, this paper focuses on the latest reflow solderable IGBT discrete products (TO247) and employs Ansys FEM 3D modeling to extract thermal resistance for the three different thermal resistance network (Zth) models. Furthermore, PLECS simulations for typical inverter conditions were used to make a comparison of different Tvj calculations, which based on the three Zth models of the discrete IGBT (between case and cooling water). This paper presents a detailed comparison of the results and methods used and introduces a novel model that aims to provide the most accurate virtual junction temperature calculations.