A Comparative Analysis of Integrated Heat Sink and Heat Pipe Cooling in a Heat Pump SiC Frequency Inverter

This paper presents a quantitative thermal comparison of five compact cooling architectures for a 30 W, 40 kHz, 700 V silicon-carbide (SiC) half-bridge used in residential heat-pump inverters. The designs—ranging from a bare aluminium heat-sink to a fully enclosed heat-pipe holder—share a strict 69 mm × 100 mm footprint. Finite-Element simulations in AN-SYS 2024 R1 predict that integrating a single 6 mm copper–water heat pipe and maximising its contact area lowers the peak MOSFET junction temperature from 511 °C to 78 °C under natural convection—an 85 % reduction that meets the ≤80 °C design target. The same change shortens the dominant thermal time constant by roughly 3.5× and raises full-load inverter efficiency by about 1.4 % points. A 1 000-cycle coupled thermo-mechanical analysis shows that all critical joints stay below 200 µε, preserving long-term reliability. These results demonstrate that heat-pipe integration—not additional fin area—is the most effective way to cool wide-band-gap devices dissipating more than 20 W/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in naturally ventilated, footprint-constrained power electronics.