Electromagnetic Design of Propulsion Motors with Superconducting Field Coils for Electrified Aircraft

Abstract

This paper describes the output power density of partially superconducting motors (PSCMs), which have superconducting field coils and copper armature windings, for electrified aircraft propulsion systems (EAPSs). In EAPSs the aircraft’s fans are driven by electric motors. For electrified aircraft with a capability of more than 100 passengers, the electric motors are required to have high output power density of 16 kW/kg or more, whereas the power density of a conventional synchronous motor is limited to around 5 kW/kg. PSCMs have a potential to achieve such a high output power density because of high current density of the superconducting field coils and high magnetic flux density generated by them. The output power densities of 5.5 MW PSCMs were estimated at different operating temperatures of the field coils by analytical equations and FEM analysis. The design results showed that the output power density reached 16.1 kW/kg at 20 K and 12.0 kW/kg at 65 K. From these results we consider that the PSCMs at 20 K have a potential to be adopted in EAPSs in terms of high output power densities. The output power density of PSCMs at 65 K is more than double compared to conventional electric motors, although the required output power density could not be attained.