Design of a wheel-hub motor with air gap winding and simultaneous utilization of all magnetic poles

This paper presents a new structure of BLDC motor applied for a wheel-hub motor for an electric vehicle. Today the physical structure of BLDC motors is dominated by a massive stator with salient poles as a framework for the windings. This construction results in high weight and in significant energy losses caused by eddy currents and hysteresis losses in the stator material. Furthermore, a huge amount of conductor material is needed, mostly with limited cross-section areas, so that resistive losses occur. In this paper a new approach to a permanent excited electrical motor is presented that allows for stator constructions with reduced weight, size, resistive and magnetic losses in combination with a very compact and high efficient air gap winding that allows for simultaneous utilization of all permanent magnets to generate very high torque. The design of a wheel-hub motor useful to drive a 4WD electric vehicle is presented.