Torque Performance Analysis of Three-Phase Flux Reversal Machines

Flux reversal machines (FRMs) have received extensive attentions in recent years due to their high torque densities, robust structures, fast transient responses, etc. This paper focuses on the analysis of the torque performances including average torque, cogging torque, and ripple torque of three-phase FRMs. First, the general expressions of instantaneous torque under no-load and rated-load conditions are analytically derived. Then, based on the analytical equations, the effects of rotor slot number, split ratio, permanent magnet thickness, and stator and rotor slot opening ratio on the torque performances are investigated and analyzed, which can be used for optimizing the structural parameters for maximum torque density and minimum pulsating torque. Finally, the theoretical analyses are validated by experiments on a 12-stator-slot/17-rotor-slot FRM prototype. Good agreements have been achieved between the simulated and experimental results.