Research on variable flux permanent magnet pole-changing machine with harmonic excitation

This paper proposes a new topology of memory machine (MM) named variable flux permanent magnet pole-changing machine (VF-PMPCM) with harmonic excitation. The machine has two sets of three-phase distributed windings in stator: power winding and control winding. The rotor framework employs reasonable arrangement of neodymium-iron-boron (NdFeB) PM poles and aluminum-nickel-cobalt (AlNiCo) PM poles. The VF-PMPCM features that its pole number can switch back and forth between two poles and six poles through altering the magnetization directions of AlNiCo PMs by applying different directions of current pulses in the control winding, and the air gap flux can be online adjusted. The topology structure and operating principle of the machine are described, and its electromagnetic characteristics are calculated and analyzed by using finite element method (FEM).