Double-Rotor Flux Switching Machine with HTS Field Coils and Superconducting Shields for Aircraft Propulsion

Abstract

In this study, a 1 MW double-rotor flux switching machine is designed for high-power density electric motors in all-electric aircraft. The motor features an air core stator that accommodates armature windings and field coils. Armature conductors utilize aluminum Litz wire at T = 20K, while YBCO superconducting tapes are employed for the field coils operating at T = 20 K. The inner and outer rotors are constructed with laminated Hiperco 50. Most notably, superconducting magnetic shields are positioned between the two rotor teeth to minimize leakage flux and guide magnetizing flux on a pre-determined path. This new motor is shown to have widely superior power density and efficiency. The motor design is evaluated across different pole/slot combinations, revealing that higher pole numbers increase power density. Specifically, a 20-pole/15-slot double rotor flux switching motor with a shield achieves a power density exceeding 100 kW/kg, with efficiency reaching up to 99.5%. This was twice the power density of a comparable design without the shield. The thermal management system has been designed for the proposed motor. The result is a machine that satisfies requirements for electric aviation propulsion applications.