A Comparison between Axial and Radial Flux Permanent Magnet In-Wheel Motors for Electric Vehicle

Axial and radial flux permanent magnet motors are widely adopted in the in-wheel direct-drive application. The aim of this paper is to compare these two kinds of motors on torque and torque density considering constraints of in-wheel direct-drive application. Both motor size and cooling condition are taken into consideration. The key geometrical parameters including split ratio and aspect ratio are pointed out and analyzed. The critical aspect ratio is proposed to judge when the AFPM motor is better or not. The finite element method simulation is employed to verify the motor performance with a specific motor size.