An improved method for monitoring the junction temperature of 1200V / 50A IGBT modules used in power conversion systems

Abstract

Insulated gate bipolar transistor (IGBT) is one of the most used devices for high-power-density and high-voltage applications such as wind turbines, electric vehicles, and smart grids. However, the field of IGBT research is still in its infancy owing to the failures that can happen to the module due to its temperature rise. Hence, the junction temperature T j measurement of the active region is essential for analyzing and predicting the degradation state of the IGBT device. In this paper, an overall study, including uses of the governing thermal equation to estimate the junction temperature T j, experimental analysis of the IGBT component during operation, and a numerical finite element (FE) study, was conducted. The thermal management FE model is conducted to predict temperature variation along time and heat spreading inside the IGBT layers. To investigate the material’s properties and structure change during operation impacting the junction temperature, scanning electron microscopy (SEM) and energy X-ray dispersive spectroscopy (EDS) were performed on the IGBT power module. Results were used to interpret the difference between the experimental and the predicted temperature values. For effectiveness validation purposes, results obtained from the proposed FE model are compared with the results of the experimental thermo-sensitive electrical parameters (TSEP) method. Good agreement was found between the experiment and the proposed FE model.