Influence of the Rotor Pole Number on Optimal Parameters in Flux-Switching PM Brushless AC Machines by the Lumped-Parameter Magnetic Circuit Model

The investigation on flux-switching permanent-magnet (FSPM) machines in existing papers has been restricted to a specific combination of stator and rotor pole numbers, viz., 12/10 stator/rotor poles. In this paper, the influence of stator and rotor pole numbers on the optimal parameters of the FSPM machines are investigated by the finite-element analysis and the lumped-parameter magnetic circuit model, respectively. It shows that, although the optimal rotor pole width for maximum torque varies with the rotor pole number, the optimized ratio of rotor pole width to the rotor pole pitch almost maintains constant, viz., ~1/3. It also shows that the 12/13 and 12/14 stator/rotor pole FSPM machines exhibit ~10% larger electromagnetic torque than the conventional 12/10 stator/rotor pole FSPM machine. The analyses are validated by an experiment made on a 12/14 stator/rotor pole FSPM machine.