In-wheel motors have been considered as one of the core technologies for the future developments of electric vehicles (EVs), where the outstanding feature is that the drive
motor is directly connected to the vehicle wheel 1. It indicates that, to the EVs, the short transmission chain and high transmission efficiency can be achieved potentially by adopting the
in-wheel motor 2. Yet, the direct-drive with in-wheel motor gaining advantages of power transmission, while it also makes the motor straightly faced with the complex drive environment,
such as the diverse operation conditions and road conditions. It means that, to the in-wheel motor, the problems of vibration and noise are more prominent and worthy of concern. This is
essential for realizing the high reliability and desirable comfort of EVs. Therefore, how to effectively suppress the vibrations and reduce noise is becoming a hot research field and full of
challenge. Then, a new perspective of radial electromagnetic force (REF) modulation is proposed for studying the vibration characteristic of a V-shaped PM in-wheel (VPM-IW) motor in
this paper. By purposely considering the modulation effect of REF into motor design, the electromagnetic vibration of VPM-IW motor is suppressed effectively.
Firstly, Fig.1(a) shows that the VPM-IW motor with the pole-slot combination of 40-pole/24-slot is selected as the design example. Fig.1(b) shows the deformation on the motor caused by
the different orders of REF. And Fig. 1(c) shows the principle of REF modulation. Then, Fig. 2(a)-Fig. 2(d) show the relationship between radial flux density (RFD) and REF. It can be
seen that, the dominant spatial order of REF, such as 4th, is generated by 4kth RFD harmonics. Hence, 4th REF can be suppressed by reducing 4kth RFD harmonics. Next, the multiobjective
genetic algorithm (MOGA) is adopted considering the force modulation effect. Fig. 2(g) to Fig. 2(n) show the comparison of performances. Fig. 2(m) and Fig. 2(n) show that the
optimal structure realizes the reduction of vibration and noise and the highest vibration peak appears around 4979 Hz, which is frequency of 4th mode.
The more detailed theoretical analysis and research results will be provided in the full paper.
1W. N. Fu and S. L. Ho, IEEE Transactions on Magnetics, vol. 46, no. 1, pp. 127-134, Jan. 2010.
2 S. Zuo, F. Lin and X. Wu, IEEE Transactions on Industrial Electronics, vol. 62, no. 10, pp. 6204-6212, Oct. 2015.