The design of Halbach array permanent magnet for In-wheel motor

Abstract

According to the structure size of automobile wheel hub, two types of outer rotor permanent magnet In-wheel motors which meet the performance requirements of electric vehicles are designed in this paper. The analysis of the electromagnetic in the motor with finite element method proves that the new Halbach array can optimize the back-electromotive force(EMF) waveform and raise the average electromagnetic torque of the motor. It can also effectively weaken the cogging torque and the torque ripple. Key words: In-wheel motor；Halbach；finite element analysis I. INSTRODUCTION In-wheel motor is also called hub built-in motor. The mechanical device integrates motor, transmission system and brake system was invented by an American named Robert in the 1950s[1]. Compared with the traditionally electric vehicle drive system, the transmission, clutch, suspension, gearbox and other related parts can be eliminated on vehicles equipped with in-wheel motors. The structure of the vehicle can be sampled. The drive mode can be the front-wheel drive, the rear-wheel-drive or the four-wheel drive. More and more researchers and electric vehicle manufacturers around the world focus on the In-wheel motors. The DC motor, the switch reluctance motor, the brushless permanent magnet DC motor, the induction motor and the permanent magnet synchronous motor can be selected as the motor of in-wheel drive system for electric vehicles. The permanent magnet synchronous motor becomes an ideal choice presently for a number of reasons: smaller size, higher efficiency, power density and power factor. Two 8.5 kW in-wheel motor models with the traditional and the new Halbach permanent magnets array are established in this paper. The air gap magnetic flux density waveform, electromagnetic torque and cogging torque of the motors with different permanent magnet arrays are compared by the Finite Element Analysis (FEA). The analysis shows that the Halbach permanent magnet array has the addition benefit of optimizing the EMF waveform. The electromagnetic torque is improved. The cogging torque and the torque ripple are reduced too.

Design and temperature field analysis of conical outer rotor hub motor

“…Compared with synchronous motors, vernier motors possess the benefits of high torque and low speed [1,2,3,4]. Therefore, PMVM is more suitable for electric vehicle hub motor [5,6,7].…”

Comparative Analysis of Consequent-Pole Flux-Switching Machines with Different Permanent Magnet Arrangements for Outer-Rotor In-Wheel Direct-Drive Applications

“…The outer-rotor (OR) PMSM is a potential choice for in-wheel direct-drive applications as the rotor can be directly combined with the wheel hub [3]. In low-speed direct-drive applications, emerging magnetic-geared machines have been found to perform excellently [4].…”

Multi-objective Optimization and Performance Comparison of Different Driving Configurations of In-wheel Motors

“…Afterward, Gong et al [11], Ifedi et al [12], and Chung et al [13] developed direct driving IWMs based on outer-rotor radial flux permanent magnet synchronous motor (PMSM) separately. Furthermore, outer-rotor PMSMs with different arrangements of permanent magnets such as Halbach type [14], [15] and Spoke type [16], [17] for direct driving IWMs have been researched. Besides, the design and optimization of diverse concepts of IWMs such as reluctance machines [18], [19] and vernier machines [20], [21] have been conducted.…”