Scaling an Axial Flux Permanent Magnet Motor for Different Electrified Aviation Applications

This paper presents a base topology of an axial flux permanent magnet (AFPM) motor selected for a fully electric powertrain for a single-aisle aircraft based on the specifications provided in the Aviation-Class Synergistically Cooled Electric-motors with iNtegrated Drives (ASCEND) project from the Advanced Research Projects Agency-Energy (ARPA-E). The ASCEND motor is assessed for scalability to fit other aircraft profiles. The scaled design’s performance is compared with the ASCEND design to understand the effect of scaling and avenues of improvement. The SCEPTOR project requires 54% as much speed and 83% as much torque as ASCEND; at these specifications, the SCEPTOR motor is 1.6% less efficient than the ASCEND motor. This is because the DC copper losses are a larger fraction of the output power. While the core and magnet losses are lower than the ASCEND design at a greatly reduced speed, these were already smaller than the copper losses. The SUSAN design requires a 36% increase in speed and a 317% increase in torque. The SUSAN motor is 0.7% less efficient than the ASCEND motor due to the dominant AC losses. At this larger scale, the active torque and power density were increased significantly, whereas by scaling down the active torque and power density were reduced.