Hollow Micropillar Evaporator for Cooling Wide-Bandgap Silicon Carbide Power Converters

State-of-art power modules use fast-switching, high-voltage wide band gap MOSFETs, leading to die-level hotspots up to 1 kW cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> . Microscale evaporative cooling can dissipate large heat fluxes with low pumping power due to large latent heat of vaporization resulting from the phase change. We present a size, weight, and power (SWaP) optimized power electronic system with a novel direct-to-direct bonded copper (DBC) evaporative cooling module with hollow copper micropillars sustaining R-245fa microdroplets. Simulation results show a heat dissipation and heat transfer coefficient of 289 W cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> and 24.1 kW m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , respectively, with a required pumping power of 0.96 W, which is 15× lower than commercial cold plate technology. By removing the baseplate and bonding the evaporative module directly to the DBC, we reduce the junction-to-coolant thermal resistance and system weight by 60% and 88% respectively. A 3D manifold distributes the coolant to the evaporator, while ensuring a hermetic seal.