Practical Thermal Solution for 1-MVA Three-Level ANPC Inverter in Aerospace Applications

In aerospace applications, high-performance cooling systems are essential to ensure the reliability of power inverters under extreme operating conditions. This article presents the design and analysis of a practical pin-fin liquid cooling system for a 1-MVA silicon carbide (SiC)-based three-level (3-L) active neutral point clamped (ANPC) inverter. The thermal and hydraulic performance was evaluated through finite element analysis (FEA) models of SiC power modules and computational fluid dynamics (CFDs) simulations, confirming the heat transfer efficiency required for aerospace environments at $70~^{\circ }$ C coolant temperature. The cooling solution leverages a staggered pin-fin arrangement to improve heat transfer efficiency while maintaining manufacturability and cost-effectiveness. Two different cold plate configurations—series and parallel—were compared for uniform fluid distribution and cost-effectiveness. Special attention was also given to sealing design, ensuring reliability in preventing coolant leakage. The system effectively manages over 7.2-kW power loss, maintaining junction temperature $T_{j}$ safely below the $150~^{\circ }$ C limit. Experimental tests validated the cooling system’s hydraulic and thermal performance, demonstrating its ability to handle high power losses with low pressure drop, making it a robust and cost-effective solution for high-power aerospace inverters.