Segmented Rotor Magnetic Flux Switching Device for High-Performance Electric Motorcycles and Scooters Applications

Abstract

The global transition toward sustainable transportation and carbon-neutral mobility has intensified research into advanced electric propulsion systems for light two-wheel electric vehicles. Conventional electric scooters and motorcycles commonly employ surface-mounted permanent magnet synchronous motors (SPMSMs) and permanent magnet direct current (PMDC) motors. However, these machines suffer from operational limitations associated with rotor-mounted permanent magnets, including thermal demagnetization, excessive rotor eddy-current losses, limited overload capability, and reduced efficiency during high-speed flux-weakening operation. This paper presents a high-performance, three-phase, 12-stator-slot / 10-rotor-pole (12S/10P) permanent magnet flux switching machine (PMFSM) employing an outer segmental rotor topology optimized for direct-drive electric scooter and motorcycle applications. The proposed machine integrates radially magnetized stator-mounted permanent magnets and concentrated armature windings with a passive, robust segmented rotor to improve torque density, thermal reliability, and electromagnetic flux modulation. Machine geometry and electromagnetic parameters were developed using modern electric mobility constraints and analyzed via two-dimensional finite element analysis (2D-FEA) in JMAG Designer. Simulation results demonstrate significantly enhanced electromagnetic performance compared with conventional commercial SPMSMs. The proposed machine achieves a peak electromagnetic torque of 112 N.m and a continuous power output exceeding 6.2 kW at a rated speed of 1900 rpm, while exhibiting minimized rotor losses and an expanded constant-power speed range. Furthermore, the segmental rotor topology improves magnetic loading capability and mechanical robustness while reducing active rare-earth material utilization by approximately 15 %. The study establishes that the proposed outer-rotor segmental PMFSM topology represents a highly viable and promising propulsion solution for next-generation, high-efficiency, long-range electric two-wheelers.