Comparative Analysis of Slotless and Coreless Permanent Magnet Synchronous Machines for Electric Aircraft Propulsion

Electrification of the propulsion motor for electric aircraft has become an emerging research hotspot recently. In fact, the direct-drive system on the electric aircraft is to coaxially connect the motor with the propeller to produce the thrust or lift force. Also, aircraft propulsion requires high speed, high power density, high efficiency and ultra-light weight for direct drive motors. This paper focuses on the slotless and coreless stator topologies to achieve smooth propulsion. First, the machine models are proposed and compared, with explanations of unique designs. Then, since the slotless windings are very different with slotted stator windings, the winding analysis is carried out, including the arrangement, flux linkage and induced voltage. Furthermore, the no-load and rated load performances for the proposed machines are implemented by FEA tools. Finally, comparison results are used to validate the superiority of the proposed machines.