On the Mechanical Design and Thermal Management of a 1-Megawatt Inverter for Aerospace Propulsion Applications

Abstract

The aerospace industry’s shift towards electrification is accelerating rapidly, driven by the need to reduce emissions, enhance energy efficiency, and improve propulsion system performance. High-power inverters are central to this transition, acting as the critical interface between power sources and propulsion motors. To enhance this transition, power densities of these systems must increase. Achieving higher power densities in aerospace applications introduces significant challenges, particularly in thermal management and packaging. This work presents an advanced thermal management strategy using jet impingement cooling, facilitated by additive manufacturing. The prototype successfully maintains junction temperatures below 150 °C under worst-case operating conditions and reduces pressure drop across the cold plate from 8.9 PSI to 5.8 PSI after internal optimization. Modularity is also an emerging trend in the aerospace field, as it allows system customization. The inverter design adopts the Power Electronic Building Block (PEBB) approach, splitting the 3 output phases of the inverter into standalone units. Three PEBB units combine to create a full 1 MW inverter. Passive cooling fins and strategically placed high-current connectors enhance system efficiency and reliability while ensuring compliance with electrical insulation requirements and electromagnetic compatibility considerations. The presented inverter achieves a specific power of 49 kW/kg, significantly surpassing existing benchmarks. This advancement underscores the critical importance of mechanical design optimization particularly in thermal management and packaging in pushing the boundaries of power density in aerospace power electronics.