This paper investigates the feasibility of an interior permanent magnet (IPM) rotor for 1 MW-class high-speed permanent magnet synchronous machines (PMSMs) in a hybrid propulsion system of electrified aviation. A double-layer IPM machine and a surface-mounted PM (SPM) benchmark machine with Halbach-array PMs, which are typically employed in aviation applications; are designed using the same design specifications, the same stator, double-three-phase winding layout, physical air-gap length, outer and inner diameters of rotor; and the same materials. The rotor robustness of the IPM machine using high-strength iron material has been verified through mechanical strength analysis with an outstanding safety factor margin. The electromagnetic performances of IPM and SPM benchmark machines are compared. It is found that the IPM design can achieve similar high torque/power density and high efficiency to the SPM benchmark machine, using 48% less rare-earth PM materials and a simpler rotor structure without a carbon fiber sleeve for easy manufacturing. The investigation confirms the feasibility of IPM topology for MW-class high-speed aviation propulsion machines for lower cost and more sustainable purposes.
Xiao et al. (Wed,) studied this question.