Geometrical pole shape optimization of an outer rotor synchronous reluctance motor for output torque enhancement

This article explores optimizing design for Permanent magnet (PM) free outer rotor synchronous reluctance machines to be used as in-wheel motors for electric vehicles. The primary objective is enhancing torque output by systematically analyzing various rotor pole shapes and parameters such as pole depth, arc angles, rib thickness, channel width, and fillet radii. These parameters were studied on four different types of pole shapes. Using ANSYS Maxwell software, the analysis is performed on an outer rotor motor with a diameter of 190 mm and a rated speed of 1200 RPM. The results indicate that outer rotor machines with configurations such as an inner arc angle of 9 degrees and an outer arc angle of 24 degrees exhibit optimal torque output for pole shape 1. Moreover, the study reveals that an increase in pole depth (SB) corresponds to an increase in torque output, while rib thickness reduces torque output. Additionally, the research explores the impact of fillet radii on torque performance. This study provides the effects of essential features of critical design parameters on reluctance torque for maximizing average torque in outer rotor motors utilized in EV applications.