A high-speed, high-frequency, air-core PM machine for aircraft application

High number of magnetic poles in an electric machine allows reduction in radial thickness of stator and rotor yoke and thus heavy alloy. If frequency is allowed to increase with pole-count (constant speed), power level can be maintained. Thus, high frequency, together with high pole count, can improve power density of rotating electric machines. The proposed high frequency concept is applied to designing a 1 MW motor, with power density and efficiency goals of > 13kW/kg and > 96%, respectively.