Development of a 20-Pole-24-Slot SPMSM With Consequent Pole Rotor for In-Wheel Direct Drive

In-wheel motors bring a fundamental change in electric vehicle technology by removing conventional mechanical components and freeing up space inside the vehicle body. This approach ultimately helps to realize all-wheel independent control for improved vehicle dynamics and increased vehicle design freedom. However, when space allowed for an in-wheel motor is taken into consideration, high torque density, high efficiency, and widespeed- range capability are typically required. This paper specifically investigates a 20-pole-24-slot surface permanent magnet synchronous motor with consequent pole rotor for in-wheel direct drive since this topology is well suited for high-pole motors and thus high-torque directdrive applications. Extensive finite-element analysis is carried out to characterize the proposed motor, and the practical feasibility of the proposed motor is discussed. Finally, the validity of the analysis was experimentally verified.