Progress in the Development of a High-Performance Heat Sink for Hybrid Electric Vehicle Inverters

We have previously reported on the development of a novel active heat sink (AHS) for high-power electronic components offering unparalleled capacity in high-heat flux handling and temperature control. AHS employs convective heat transfer in a working fluid circulating in a miniature closed and sealed flow loop. High flow velocity, good flow attachment, and relatively high thermal conductivity of working fluid lead to ultra-low thermal resistance around 0.1 deg C/W. AHS appears very suitable for directly interfacing a hybrid electric vehicle (HEV) inverter to engine coolant loop. Alternatively, AHS may be used to interface inverter electronics to an air-cooled heat exchanger. As a result, the traditional dedicated liquid coolant loop for thermal management of the inverter can be eliminated, the inverter subsystem can be greatly simplified, and the power train electronics made much more compact. Our previous work focused on AHS with working fluids based on liquid metals. This paper reports on AHS development testing with water-based working fluid, which are more suitable for automotive applications. Also presented are an AHS concept updated for high-volume, low-cost series production, and a concept for AHS integration into an automotive inverter.