Retrofitting a Hairpin Stator Winding Aircraft Propulsion Motor with a Superconducting Rotor
Andreas Lindner, Xinjun Liu, Daniel Walch
Abstract. Currently, there are different future aircraft concepts considering hybrid electric and fully electric propulsion system. To achieve an electric aircraft there is the need for electric motors with a higher power density and lower weight than conventional solutions currently available [1]. Using hairpin stator windings increases the power density of the machine due to their high slot fill factor and good thermal properties. Furthermore, they enable automated manufacturing and decreasing costs. To achieve a further step regarding higher power densities, the use of superconductors in electric motors is proposed [2]. They have minor DC resistance in the superconducting state, which could minimize the motor losses and enable a generation of high flux density motors. Both stator and rotor could be realized using superconductors. A rotating magnetic field is generated in the stator, which is why AC currents are required. Consequently, AC losses still occur in machines with super-conducting stator (SC-stator) and must be considered to prevent quenching [3]. When using SC-rotors, an electrically excited synchronous machine is designed. Here, DC currents are used to generate a constant magnetic pole system. These AC losses are disregarded in the first place which simplifies the initial design process.
Keywords
Superconducting Electric Motor, Permanent Magnet Machine, Electric Aircraft, Electric Excitation
Published online 7/20/2026, 7 pages
Copyright © 2026 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: Andreas Lindner, Xinjun Liu, Daniel Walch, Retrofitting a Hairpin Stator Winding Aircraft Propulsion Motor with a Superconducting Rotor, Materials Research Proceedings, Vol. 69, pp 757-763, 2026
DOI: https://doi.org/10.21741/9781644904251-134
The article was published as article 134 of the book CEAS – AIDAA Conference 2025
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
References
[1] W. Cao, B. C. Mecrow, G. J. Atkinson, J. W. Bennett, and D. J. Atkinson, “Overview of Electric Motor Technologies Used for More Electric Aircraft (MEA),” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3523–3531, 2012. https://doi.org/10.1109/TIE.2011.2165453
[2] P. Alvarez, M. Satrustegui, I. Elosegui, and M. Martinez-Iturralde, “Review of High Power and High Voltage Electric Motors for Single-Aisle Regional Aircraft,” IEEE Access, vol. 10, pp. 112989–113004, 2022. https://doi.org/10.1109/ACCESS.2022.3215692
[3] R. Mellerud, M. Leandro, C. L. Klop, C. Hartmann, and J. K. Nøland, “Influence of Harmonic Distortion on AC Losses in Converter-Fed Superconducting Electrical Machines,” IEEE Trans. Appl. Supercond., vol. 35, no. 2, pp. 1–7, 2025. https://doi.org/10.1109/TASC.2024.3517669
[4] X. Liu, T. Schriefer, D. Walch, A. Lindner, M. Hofmann, and B. Eckardt, “Multi-phase Hairpin Winding Electric Machine for Hybrid Electrical Aviation Applications,” Production Technologies and Systems for E-Mobility (EPTS), 2025.
[5] R. Mellerud, C. Hartmann, C. L. Klop, S. Austad, and J. K. Nøland, Eds., Design of a Power-Dense Aviation Motor With a Low-Loss Superconducting Slotted Armature, 2023.
[6] H. S. Ruiz et al., “Critical current density in advanced superconductors,” Progress in Materials Science, vol. 155, p. 101492, 2026. https://doi.org/10.1016/j.pmatsci.2025.101492
[7] G. Bertotti, “General properties of power losses in soft ferromagnetic materials,” IEEE Transactions on Magnetics, pp. 621–630, 1988. https://doi.org/10.1109/20.43994
