Thermal Performance and Pre-Integration Tests of a Dual-Side Inverter and Stator for an Electric Propulsion Cooling System

The Ultra-Light, inTegrated, Reliable, Aviation-class, Co-Optimized Motor and Power converter with Advanced Cooling Technology (ULTRA-COMPACT) project, developed by the RTX Technologies Research Center (RTRC) through ARPA-E ASCEND program [1], aims to create a highly compact and efficient electric propulsion system for single-aisle regional aircraft. A critical focus of this project is its advanced thermal management system, designed to enhance power density and efficiency. The ULTRA-COMPACT system [2] leverages an integrated and actively controlled thermal management system that delivers coolant directly to motor windings and the power converter. The stator features an innovative cooling system, constructed using additive manufacturing methods, which employs the evaporation of a low Global Warming Potential (GWP) refrigerant to prevent overheating. These cooling channels serve a dual purpose, also acting as the main structural support for the stator. A thermal test rig along with an additively manufactured cold plate for cooling the motor drive was built and the performance of this cold plate was evaluated at different heat loads to ensure effective thermal management under various operating conditions. This comprehensive approach to thermal management is critical for achieving the system's target power density of 12.2 kW/kg and efficiency of 96.6%, paving the way for more energy-efficient and quieter aircraft.