Finite element analysis of thermal contact resistance in Press-Pack IGBT module

Abstract

PP IGBT is a new type of electronic device, which has different characteristics, such as compact structure, double-sided heat dissipation, and large scale parallel chip can be realized in a single device. It is widely used in power system engineering applications such as flexible direct current transmission, flexible alternating current transmission, and photovoltaic access. PP IGBT are generally used in series applications requiring external pressure to maintain electrical and mechanical connections between the internal components. For PP IGBT, thermal resistance is an important indicator related to its thermal characteristics. The thermal resistance of PP IGBT includes not only the thermal resistance of the material of each component, but also the thermal contact resistance. A plurality of contact surfaces is formed between each material layer inside the device to form a thermal contact resistance. Insufficient contact surface will increase the thermal contact resistance, resulting in high temperature or uneven temperature distribution. Therefore, the thermal contact resistance will have an important effect on its performance. In this paper, through the establishment of single die PP-IGBT module three-dimensional finite element model, thermal-electrical-structural coupling analysis was carried out on PP IGBT. Calculate and compare the values of the thermal contact resistance of the devices before and after 250000 power cycles experiment. The effect of the contact surface morphology on the thermal contact resistance is mainly studied. Furthermore, the effect of the thermal contact resistance of all material layers on the overall thermal resistance of the PP-IGBT is obtained.