Comparison of Low-Cost Single-Phase Wound-Field Switched-Flux Machines

This paper presents a comparative study of two types of low-cost single-phase wound-field switched-flux machines with dc field and ac armature windings having the same coil-pitch of 2 slot-pitches and having different coil-pitches of 1 and 3 slot-pitches, respectively. Both can share the same stator lamination, but the latter can have shorter end windings and lower iron loss for the 12-slot/6-pole configuration. The performance, including back electromotive force, cogging torque, and static torque, of both machines are analyzed and compared by 2-D finite-element analysis and validated by experiments on the prototype machines.