Influence of Cooling Fin on Tj of HVIGBT Power Module

Inhalt:
This paper evaluates the impact of cooling design-related parameters on the junction temperature (Tj) of IGBT and diode chips in two HVIGBT power modules—Product-R and Product-XB—that share identical external dimensions but differ in chip layout. A steady-state thermal analysis based on the finite element method was conducted, in which cooling design parameters were varied to compute the Tj of each product. For the purpose of establishing design guidelines, the objective variables were defined as the average junction temperature (Tave), the maximum junction temperature (Tmax), and the temperature difference (DeltaT). These objective variables were then correlated with the selected parameters using multiple linear regression, allowing for the identification of the most influential parameters and the quantification of their contributions. The results demonstrate that, within the design range considered in this study, the thermal conductivity of the thermal interface material (TIM) is the dominant parameter affecting cooling performance. Furthermore, Product-XB consistently exhibited lower Tave and Tmax values than Product-R under all conditions, indicating superior thermal performance and reduced sensitivity to parameter variations in cooling design.