Case Temperature Estimation for Low-Air-Pressure Forced Air-Cooled Power Devices With Simple Power Loss Measurement

Low air pressure environments reduce the convective heat transfer efficiency, while frequent strong winds increase the likelihood of health degradation of heatsink due to duct blockage. These factors alter the external thermal flow paths for forced air-cooled power devices and pose significant challenge for accurate estimation of case temperature. Existing case temperature estimation methods have incorporated health degradation of heatsink into thermal network modeling, but not in the low air pressure environments. These methods also require additional measurement of electrical parameters such as device current, device temperature, and chip voltage drop, to obtain power loss information. This paper proposes a novel case temperature estimation method for forced air-cooled power devices under low air pressure and health degradation of heatsink. The influence of both the low air pressure and health degradation of heatsink on thermal parameters is examined, and thermal parameters are extracted by computational fluid dynamics simulation considering the fluid temperature distribution. Besides, a simple power loss measurement scheme that measures the temperature rise of heatsink fluid is developed for efficient case temperature estimation. Experimental results verify the accuracy and applicability of the proposed method under low air pressure environments.