An Innovative Electric Motor Topology Developed for 2- and 3-Wheelers

This paper presents a comparative study between the state-of-the-art electrical machine topologies and an alternative innovative rare-earth-free solution. Focus is placed on the electric 2- and 3-wheelers. This application requires electrical machines typically in the range of 4 kW to 10 kW, to be manufactured and designed for cost-effective small to mid-size vehicles. The comparison is made taking into account major 2- and 3-wheelers attributes of efficiency, cost, sustainability, weight and performance. The different electrical machine topologies discussed in this paper are interior permanent magnet machines, axial flux permanent magnet machines, and axial flux electrically excited synchronous machines. This study is carried out on a 5.5 kW electrical machine. However, this paper results and conclusion may be extended also to other power levels in this segment. Besides the comparison in attributes, production aspects are also taken into account in this study. Focus in this research is put on central-drive propulsion architecture which covers majority of 2- and 3-wheelers market today. In-wheel configuration will be addressed in future publications.