A Yokeless and Segmented Armature Axial Flux Machine With Novel Cooling System for In-Wheel Traction Applications

This article proposes a new yokeless and segmented armature axial flux machine applied in-wheel traction. The loss analysis for the motor is performed based on finite-element method, and several methods are adopted to increase the efficiency and the output power of the motor. Subsequently, a novel cooling system is proposed, and the thermal analysis of that is conducted. On this basis, computational fluid dynamics (CFD) is developed to investigate and optimize the cooling system to increase the heat transfer efficiency. And finally, the in-wheel motor is manufactured and tested. It can be concluded that the measured data match well with the results of the electromagnetic and CFD analysis, and the peak power of the motor has been increased from 50 to 65 kW before and after improvement.