Passive In-Slot Heat Path Realization for Extending the Operating Limits of an Aircraft Propulsion Motor

This article studies the combined thermal and electrical characteristics of different in-slot conductive heat path (HP) materials and shapes to reduce the winding hotspot temperature and improve electrical motors’ output power and performance. Combinations of analytical and 2-D finite thermal models are developed and experimentally validated to consider the electromagnetic (EM) losses and temperature distributions within a slot-only model, as well as for a full motor. The models are used to assess a range of materials and operating conditions. The main parameters, such as the thermal and electrical conductivity and thickness of the in-slot passive heat conductive paths, are varied to generate a wider understanding of their operation for the future implementation of the HP concept. Finally, the HP is adopted for a high-performance aircraft propulsion motor (ProMo) to extend the operation limits. The analysis considered the thermal and EM aspects and the output power and power density have increased by 21% using the proposed HP.