Design of a Modular In-Wheel Motor with High Fault-Tolerant Performance and Low MMF Space Harmonic

In-wheel motors, as the core power component of electric vehicles, require not only high power density but also high reliability and fault-tolerant (FT) capability. This article proposes a modular permanent magnet (PM) in-wheel motor and design to receive the high FT performance and low magnetomotive force (MMF) space harmonic. First, according to the working mechanism and main faulty types of the modular FT motor, the corresponding FT control strategies are given, and the slot-pole combination with high FT performance for the modular motor is developed. Second, the electromagnetic characteristics of the modular in-wheel motor are investigated. The relationship between the FT performance and the inductance parameters is linked through the magnetic coupling coefficient. The design requirement for the inductance of this kind of motor is proposed. Third, the torque performance of the motor is studied, and the factors affecting torque performance during fault and FT operations are revealed. Finally, a prototype with a slot-pole combination of 24S16P and four modules is produced, and the electromagnetic characteristics of the motor under FT operations are verified by experiments.