Speed Range Extension for E-core Outer-Rotor Flux-Switching Permanent Magnet Machines Through Winding Reconfiguration

In order to extend the speed range of E-core outer-rotor flux-switching permanent magnet (OR-FSPM) machine, this paper proposes two derived structures from the perspective of winding reconfiguration. By introducing another set of winding, outer-rotor dual-armature flux-switching (OR-DAFS) machine and outer-rotor hybrid-excitation flux-switching (OR-HEFS) machine are developed respectively. With the aid of general air gap field modulation theory, operation and corresponding speed range extension principles are revealed for two derived topologies. The result indicates that the speed range extension of two derived topologies are closely related to different spatial harmonics groups. By means of the performance analysis, a thoroughly comparison is carried out for the speed range extension capabilities of the two derived topologies, and their advantages and disadvantages are summarized in this process. The OR-DAFS machine could provide higher output torque and wider speed range, while the speed regulation of OR-HEFS machine is more convenient. Most importantly, design principles of OR-DAFS machine and OR-HEFS machine are concluded to provide a guideline for the purpose of speed range extension.