Comparison of alternate mechanically adjusted variable flux switched flux permanent magnet machines

Novel topologies of switched flux permanent magnet (SFPM) machines with mechanically movable flux adjusters (FAs) for either all or alternative stator poles in order to extend the operation speed range are developed and analysed in this paper. Compared with the FAs which are located outside all of the stator poles of SFPM machines (all FAs), the alternative stator pole FA structure (alternative FAs) uses half of FAs. Flux-linkage, cogging torque, static torque waveforms, torque- and power speed curves in 12/10, 12/13 and 12/14 stator/rotor pole SFPM machines with all and alternative FAs are predicted and compared by 2D and 3D finite element analyses (FEA), and partially experimentally validated. Compared with 12/10 stator/rotor combination, the 12/13 and 12/14 SFPM machines have higher maximum speed with both alternative and all FAs.