Comparison of Modular PM Propulsion Machines for High Power Density

Electrification of aircraft propulsion will require significant improvements in the power density of electric machines beyond the current state-of-the-art. Permanent magnet (PM) synchronous machines are capable of achieving high power density values, but selection of the rotor topology is sensitive to the application. This paper presents and compares four 1 MW highspeed PM machine designs, including variations of surface and interior PM machines. Each design meets identical specifications and is compatible with stator modularization, which offers multiple drive system benefits. The performance and features of the developed machines are compared, and a preliminary PM machine design using an inner rotor surface PM machine topology is presented for further investigation as a candidate for a future aircraft propulsion system.