Characteristics Analysis and Comparison of High-Speed 4/2 and Hybrid 4/4 Poles Switched Reluctance Motor

This paper presents a characteristics analysis and performance comparison of high-speed two-phase 4/2 and hybrid single-phase 4/4 switched reluctance motors (SRMs). Although the motors are advantageous as high-speed drives, both conventional structures have high torque ripple as a result of the presence of the torque dead zone. In this paper, solutions to the torque dead zone problem for each motor are discussed. For the 4/2 SRM, a wide-rotor stepper-type is adopted, while for the 4/4 SRM, the structure is changed to a hybrid by adding permanent magnets (PMs). Both motors have a non-uniform air gap to modify their inductance profile, which leads to the elimination of the torque dead zone. A finite-element method was used to analyze the characteristics of each motor. Then, the manufactured motors were tested through experiments, and lastly, their performance was compared.