Weight Reduction for Airborne Electric Motors Due to Higher Frequency Operation

Weight reduction is a mission-critical challenge in UAV electric propulsion. This article demonstrates how GaN-based inverters, enabling switching frequencies up to 80–100 kHz, unlock propulsion machine topologies previously incompatible with silicon-based drives. Experimental results on a 48 V GaN platform (EPC2361) confirm that doubling the switching frequency from 40 kHz to 80 kHz maintains the total system efficiency virtually unchanged due to a self-compensating mechanism between reduced motor harmonic losses and increased inverter switching losses. This frequency headroom enables the adoption of Permanent Magnet Vernier (PMV) motors, which exploit magnetic gearing and flux modulation to achieve high torque density. An optimized 18-slot, 60-pole Vernier machine achieves efficiency fully comparable to a conventional PMSM (approximately 95% at 80–100 kHz) while reducing the electrical machine weight by a factor of 12%.