Influence of Outer Diameter-to-Axial Length Ratio on Torque Density in an Axial Wound Field Flux Switching Motor with Segmental Rotors

Downsizing and weight reduction of motors are critical in aircraft applications. This paper investigates the effect of the lengthto-diameter ratio (L/D) on the torque density of an axial wound field flux switching motor (AWFFSM) with segmental rotors. The torque density is analyzed for L/D values ranging from 0.106 to 0.312, while maintaining a constant motor volume. The results show that the motor achieves the highest torque-to-volume density at L/D = 0.156 and the highest torque-to-weight density at L/D= 0.127. Furthermore, the motor weight decreases as the design becomes flatter. These findings provide useful insights for guiding the downsizing and weight optimization of AWFFSMs.