Analytical Modeling of the Electromagnetic Vibration and Noise for an External-Rotor Axial-Flux in-Wheel Motor

This paper presents an analytical model of the electromagnetic vibration and noise for an external-rotor axial-flux in-wheel motor (AFWM). First, the air-gap flux density is calculated and the influence of edging effect is taken into account through a radial correction function. On this basis, the electromagnetic force acting on the surface of the magnets is obtained. Then, the modal parameters and shapes are calculated and the surface displacement of the AFWM is obtained via a modal superposition method. Finally, sound radiation efficiency is explored to predict the electromagnetic noise. The analytical model is validated through simulation and experiment, respectively. It turns out that the analytical model can predict the electromagnetic vibration and noise of the AFWM quickly and effectively over a wide speed range, which is of great significance for the design of low-noise axial-flux motors.