Electro-thermal finite element analysis of IGBT module under sinusoidal current load

Abstract

Insulated Gate Bipolar Transistor (IGBT) is one of the most advanced power electronic devices to realize power conversion and control, which has a strong current processing capability. It is applied more and more widely. In the service process, high current, high voltage and high switching frequency will cause IGBT module to produce greater power losses, resulting in module temperature rise. Temperature has a great influence on the reliability of IGBT. In this paper, the electrothermal finite element analysis of IGBT module under sinusoidal current load is carried out by means of finite element numerical simulation. The temperature distribution and current density distribution of IGBT module are obtained. In order to compare the difference of temperature distribution between sinusoidal current load and direct current load, the electro-thermal analysis under direct current load is also carried out. The results show that the main heat producing area of IGBT module is IGBT chip. In the process of electrical-thermal analysis, the Joule heat generated by IGBT chips conducts downward and eventually dissipates from the base plate to the outside. The current density distribution on the surface of IGBT chips is uneven. The current density near the Al bonding wires is larger, while the current density at the center and edge of the chips is smaller. By comparing the results of electro-thermal analysis under sinusoidal current load and direct current load, it is found that the temperature rise rate, the temperature fluctuation range, the time to reach the maximum temperature and the current density change are quite different under different current waveforms.