Thermal Analysis and Junction Temperature Estimation under Different Ambient Temperatures Considering Convection Thermal Coupling between Power Devices

Abstract

The convection thermal coupling between adjacent power devices in power converters is dependent on the ambient temperature. When the ambient temperature changes, the convection thermal coupling also changes. This results in an inaccurate thermal model that causes errors in the prediction of the thermal distribution and junction temperature based on a fixed ambient temperature for power devices in converters application. To solve this variable-ambient-temperature-related issue, a thermal coupling experiment for semiconductor power devices (the MOSFET and diode) was performed to discuss the influence of the thermal coupling effect between adjacent devices and the FEM (Finite Element Method) thermal models for the power devices considering the convection thermal coupling are established. Through these simulations, the junction temperatures of devices under different ambient temperatures were obtained, and the relationships between the junction temperature and ambient temperatures were established. Moreover, the junction temperatures of power devices under different ambient temperatures were calculated and temperature distributions are analyzed in this paper. This method shows a strong significance and has potential applications for high-efficiency and high-power density converter designs.

Emerging Trends and Challenges in Thermal Management of Power Electronic Converters: A State of the Art Review

“…Figure 62 shows the obtained results from this study, demonstrating the proposed method's accuracy. Wei et al [258] proposed another thermal modeling approach considering convection thermal coupling for accurately estimating the junction temperature under varying ambient temperatures. This study developed a FEM-based model for establishing a relationship between junction temperature and variation in ambient temperature.…”