Design of Spoke Type Axial Flux Permanent Magnet Synchronous Motor with Ferrite Magnet

Abstract

As all-electric aircraft (AEA) continue to attract significant attention, axial flux permanent magnet synchronous motor (AFPM) have emerged as a promising solution due to their inherently high power density. However, the reliance on rare-earth permanent magnets (PMs), which a key technology enabling this performance, poses challenges due to their cost and limited supply. In this paper, the spoke type AFPMSM with ferrite PMs is proposed to address these limitations. While the magnetic flux of surface PM (SPM) type AFPM becomes saturated with increased PM thickness, the magnetic flux of spoke type AFPM can increase for the PM thickness because the PM area is proportional to PM thickness. Based on the magnetic equivalent circuit, the magnetic flux of SPM and spoke type AFPM is compared to assess the torque potential of the spoke type AFPM. The design of spoke type AFPM is conducted for pole/slot combination and the parametric design based the defined design parameters under the design constraints. Finally, the proposed machine is evaluated against a reference model through performance comparison, validating the effectiveness of the spoke type AFPM.