Electric machines with very power-to-weight ratios are inevitable for hybrid electric aircraft applications. One potential technology that is very promising to achieve the required power-to-weight ratio for short-range aircraft, are superconductors u
sed for high current densities in the stator or high magnetic fields in the rotor. In this paper, we present an indepth analysis of the potential for fully and partially superconducting electric machines that is based on an analytical approach taking into account all relevant physical domains such as electromagnetics, superconducting properties, thermal behavior as well as structural mechanics. For the requirements of the motors in the NASA N3-X concept aircraft, we find that fully superconducting machines could achieve 3.5 times higher power-to-weight ratio than partially superconducting machines. Furthermore, our model can be used to calculate the relevant KPIs such as mass, efficiency and cryogenic cooling requirements for any other machine design.
The use of high-temperature superconductors in electric machines offers potentially large gains in performance compared to conventional conductors, but also comes with unique challenges. Here, the electromagnetic properties of superconducting electri
c machines with bulk HTS trapped-field magnets in the rotor and conventional copper coils in the stator are investigated. To this end, an analytical model of the electromagnetic field in radial air-gap synchronous electric machines is developed and validated, taking into account the specific difficulties that occur in the treatment of machines with bulk HTS. Using this model, the influence of pole pair number, stator winding thickness, rotor surface coverage, and air gap width on the machines Esson coefficient is calculated. In contrast to numerical simulations, the method presented here can provide results within minutes, making it particularly useful for work in early development and systems engineering, where large parameter spaces must be investigated quickly.
