Calculation and Analysis of Heat Dissipation Performance of Welded IGBT Device

Power electronic device IGBT is an important part of flexible DC converter valve. Due to the small size of IGBT chip, the high blocking voltage and high conduction current, its heat dissipation performance under the condition of repeatedly switching on/off is directly related to the system operation reliability. Therefore, it is necessary to focus on the analysis of the thermal performance of the device. According to the welding IGBT commonly used in DC converter, the transient hyperbolic method is used to test its thermal resistance. The thermal resistances of each layer as well as the total resistance are determined according to the structure function. In order to analyze the influence of various parts of the device on heat dissipation performance in detail, a complete 3D model of IGBT power electronic devices was established, including chip, substrate, base-plate, silica gel and shell. By calculating the steady state temperature field of the device, the results show that the reasonable heat convection coefficient on the bottom plate is the key factor to determine the heat dissipation performance, and the silicon heat convection coefficient has little effect on the heat dissipation performance. By calculating the transient temperature field, the results show that the maximum temperature difference among IGBTs in the device is about 3 °C, and the maximum temperature difference among diodes is less than 1 °C, which indicates that the device has good temperature uniformity and thermal stability.