Ironless electrical machines for aviation electrification
Wen, Weilin (2026)
Kandidaatintyö
2026
School of Energy Systems, Sähkötekniikka
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2026051847797
https://urn.fi/URN:NBN:fi-fe2026051847797
Tiivistelmä
Meeting the decarbonisation targets of future aviation requires electric propulsion machines with specific power levels far beyond the capability of conventional iron-core designs. The saturation limit of iron fundamentally constrains achievable flux density and specific power, motivating the removal of iron from the active regions of the machine.
This thesis reviews the functional roles of iron in conventional electrical machines and examines the strategies used to replace each function in ironless high-temperature superconducting (HTS) designs for aircraft propulsion. Iron is shown to perform four essential functions: high magnetic permeability, mechanical support of windings, thermal conduction, and magnetic shielding. The corresponding replacement strategies are superconducting excitation, lightweight composite structures, direct cooling of windings, and active magnetic shielding.
These strategies are applied to a review of global research and industrial projects, from partially superconducting configurations to fully ironless air-core designs. The analysis shows that ironless HTS machines can achieve specific powers far exceeding conventional technology, and that cryogenic powertrain architectures cooled by liquid hydrogen are technically coherent and under active industrial development. Challenges related to technology readiness, certification, and conductor cost remain to be addressed before operational implementation becomes possible.
This thesis reviews the functional roles of iron in conventional electrical machines and examines the strategies used to replace each function in ironless high-temperature superconducting (HTS) designs for aircraft propulsion. Iron is shown to perform four essential functions: high magnetic permeability, mechanical support of windings, thermal conduction, and magnetic shielding. The corresponding replacement strategies are superconducting excitation, lightweight composite structures, direct cooling of windings, and active magnetic shielding.
These strategies are applied to a review of global research and industrial projects, from partially superconducting configurations to fully ironless air-core designs. The analysis shows that ironless HTS machines can achieve specific powers far exceeding conventional technology, and that cryogenic powertrain architectures cooled by liquid hydrogen are technically coherent and under active industrial development. Challenges related to technology readiness, certification, and conductor cost remain to be addressed before operational implementation becomes possible.