Comparative Performance Evaluation, Prototyping and Experimentation of the Double-Stator Wound-Field Flux Switching Machine

The emergence of stator-mounted wound-field flux modulation machines have created new possibilities for high torque density electric machines without brushes and slip rings. In this study, the comparative analysis of the wound-field flux switching machine (WFFSM) and DC-excited Vernier reluctance machine (DCVRM) is undertaken in terms of the double stator (DS) topology, targeting improved torque density. The finite element analysis (FEA) and parametric study of the 24-slots/10-pole DS WFFSM (DSWFFSM) and 12-slots/10-pole DS DCVRM (DSDCVRM) is undertaken using the same specifications of 1.5 kW at 300 r/min. The no-load and on-load performance is evaluated in terms of flux linkage, back-EMF, cogging torque, rated torque, overload capability and losses. The DSWFFSM demonstrates higher rated torque density (+14.9%), lower cogging torque (-72.6%) and higher efficiency (+1.6%) compared to the DSDCVRM. The parametric analysis also reveals the low torque ripple and high-power factor potentials of both machines over a wide operating range of excitation and armature currents. Due to comparative advantage, the prototype of the DSWFFSM is developed and tested to validate the study, with satisfactory results.