Efficient Microchannel Cooling of Multiple Power Devices With Compact Flow Distribution for High Power-Density Converters.

In this article, we describe a new approach for the compact and energy-efficient cooling of converters where multiple miniaturized microfluidic cold plates are attached to transistors providing local heat extraction. The high pressure drop associated with microchannels was minimized by connecting these cold plates in parallel using a compact three-dimensional-printed flow distribution manifold. We present the modeling, design, fabrication, and experimental evaluation of this microfluidic cooling system and provide a design strategy for achieving energy-efficient cooling with minimized pumping power. An integrated cooling system is experimentally demonstrated on a 2.5-kW switched-capacitor dc–dc converter, cooling down 20 GaN transistors. A thermal resistance of 0.2 K/W was measured at a flow rate of 1.2 mL/s and a pressure drop of 20 mbar, enabling the cooling of a total of 300 W of losses in the converter using several milliwatt of pumping power, which can be realized with small micropumps. Experimental results show a tenfold increase in power density compared with the conventional cooling, potentially up to 30 kW/L. This proposed cooling approach offers a new way of coengineering the cooling and the electronics together to achieve more compact and efficient power converters. [ABSTRACT FROM AUTHOR]