Comparison between Conical and Axial Flux Geometries of High-Speed Permanent Magnets Synchronous Machines

A multiphysics design has been largely investigated for high-speed radial flux machines. In contrast, few articles discuss high-speed axial flux machines. Engineers face many thermal, mechanical, and magnetic challenges when designing such structures at high rotating speeds. The torque produced is proportional to the square and cube of the outer rotor radius for radial and axial flux machines, respectively. Simultaneously, especially at high speed, the centrifugal force strongly constrains the outer rotor radius for both radial and axial machines. In this digest, a conical rotor-stator-rotor structure is proposed, which could help enhance the torque production capabilities while preserving the rotors mechanical integrity at a high rotational speed. The conical structure is compared with a traditional axial flux machine regarding the electromagnetic aspect and a heterogeneous rotor disk’s mechanical behavior at high speed.