Full-circuit 3D electro-thermal modeling of an IGBT Power Inverter

Abstract

Classical approaches to the 3D thermal simulation of electronic systems require assumptions regarding the amount of power dissipated and its distribution. Errors in such assumptions are a leading cause of resulting errors in temperature rise predictions. Although 3D electro-thermal simulations can be applied; where electrical boundary conditions are specified and current density, electrical potential and Joule heating fields predicted, such approaches are often limited to linear IV assumptions and so are not directly applicable to semiconductor materials within the electrical circuit. This paper introduces an electro-thermal calibration methodology where the effective electrical resistance of the active semiconductor layer of an IGBT chip is determined at a given driving current via comparisons to experimental measurement. The resulting full-circuit electro-thermal simulation predicts power dissipation and temperature variation throughout an entire Power Invertor module. Insights are provided into the power dissipation budget within the system, power and temperature variations within the IGBT chips which are explained with aid of an analysis of the current variation within each bond wire.