The Radial Flux HTS Synchronous Motor Stator Windings Comparison for Electrified Aircraft Applications

Abstract

Electrified aircraft propulsion systems could be a key solution for achieving zero-emission aviation. The need for efficient multi-megawatt motors with high power density makes superconducting motors a promising solution. This study investigates the performance of radial flux high-temperature superconductor (HTS) synchronous motors for electrified aircraft applications, emphasizing the impact of stator windings on power density and losses. In this study, two motor benchmarks of 450 kW and 1 MW are proposed, the impact of an iron core on the stator structure is analyzed, and various stator windings including copper/aluminium Litz wires and HTS coils are compared regarding stator AC loss as well as machine power-to-weight ratio (PTW). The result indicates that air-cored stators are preferred due to their lower weight and reduced losses, particularly in cryogenic conditions. Meanwhile, HTS coils outperform Litz wires at lower cryogenic temperatures (40 K) in terms of machine PTW. At 77 K, however, aluminium Litz wires have an advantage over HTS designs for smaller machines. This study concludes that HTS stators with an air-cored structure can be a desired topology for the future high PTW motor design required in low-emission electrified aviation propulsion systems, especially at low cryogenic temperatures achieved with liquid hydrogen ($\text{LH}_{2}$).