Passive cooling system: An integrated solution to the application in power electronics

Passive cooling systems are commonly used in power electronic industries to dissipate the tremendous excess heat generated in semiconductors devices to maintain the efficiency, reduce the thermal stress, and prevent the thermal runaway along with component failures. This research, which has been collaborated with our industrial partner, Delta-Q Technologies, aims to enhance the overall heat rejection capacity of a commercially-available naturally cooled battery charger heat sink by focusing on the fundamental heat transfer mechanisms of thermal radiation and natural convection at the same time. In this study, the effect of anodization in various types of aluminum alloy (die-cast A380, 6061) and its thermal impact was investigated. The thermal emissivity of anodized samples was measured with Fourier Transform Infrared Reflectometer (FTIR) spectroscopy. A customized test chamber was built in our lab to carry out the steady-state thermal tests. A conjugated numerical heat transfer model was developed in Ansys Fluent in case of both natural convection and thermal radiation. Various novel fin geometries for Naturally Cooled Heat Sinks (NCHx) were also designed, prototyped, tested, and compared in terms of different surface conditions and operational orientations. A sensitivity analysis of geometrical parameters in one of the most promising fin geometries, inclined interrupted fins, was performed and analyzed. The results reveal an up to 27% overall enhancement with regard to the current IC650 design (benchmark case).