Design of a 1MW-Class Permanent Magnet Machine Featuring Multiphase Hairpin Windings for Electric Aircraft Propulsion

The electrification of aircraft propulsion necessitates significantly higher efficiency, power density, and fault-tolerant reliability in electric machines compared to current models. This paper examines the integration of hairpin technology with multiphase windings, proposing a 6-phase hairpin winding configuration for 1 MW permanent magnet (PM) machines featuring 96 slots and 16 poles. This design, in comparison to similar 3-phase PM machines, eliminates undesirable space harmonics in the stator magnetic motive force (MMF), reduces eddy current losses in the rotor PM, and lowers AC losses in the hairpin windings. Furthermore, it enhances power density by allowing a more compact stack length. To optimize the power density and efficiency of the proposed machine, a Multi-Objective Genetic Algorithm (MOGA) is employed. Finite element analysis (FEA) suggests that this improvement could boost power density to 35-40 kW/kg (for active mass), compared to the state-of-the-art 1 MW machines that use other winding technologies, such as Litz wire and high-temperature superconducting (HTS), which achieve 20-25 kW/kg.