Three-phase flux reversal machine (FRM)

A flux reversal machine (FRM) is a doubly-salient stator-permanent magnet (PM) machine with a windingless rotor, where the flux reverses polarities in the stator concentrated coils. The FRM may be built in single- or multiple-phase configurations. The three-phase FRM is studied in terms of magnetic field distribution, cogging and interaction torque and self and mutual inductances through finite element analysis (2-D FEA). Rotor/stator geometrical variables that influence the cogging and interaction torques are identified. Rotor skewing to reduce the cogging torque is successfully demonstrated. A suboptimised configuration based on an initial-geometry prototype is documented. Other potential two-, three- and five-phase pole combinations with adequate rotor skewing angle are also given. Low electrical time constant, low torque ripple and good torque density in a rugged, easily manufactured, novel machine (the 3 phase machine) are proved through FEA. The encouraging results obtained through FEA constitute a strong foundation for the optimal design, and for the analysis of FRM transients and control.