Design of a High Starting Torque Single-Phase DC-Excited Flux Switching Machine

Because single-phase dc-excited flux switching machines (DCFSMs) consist of only copper windings and iron cores, they have great potential in low-cost and high-speed applications, such as home appliances. However, similar to other types of single-phase ac machines, single-phase DCFSMs have insufficient initial torque at some rotor positions. A novel single-phase, eight-slot, four-pole DCFSM design is presented in this paper. The key feature of this design is the enhancement of reluctance torque at positions where the machine cannot deliver sufficient initial torque output. This is accomplished by modifying the outline of a section of the rotor. Consequently, the machine has a two-layer rotor structure along the axial direction. The proposed design is validated experimentally using a prototype. The results show that the machine can start from any rotor positions with initial torque higher than 50% of the rated output torque.