Dual-Stator Two-Phase Permanent Magnet Machines With Phase-Group Concentrated-Coil Windings for Torque Enhancement

This paper presents two types of novel dual-stator two-phase permanent magnet synchronous machines (PMSMs) equipped with an advanced phase-group concentrated-coil winding and a spoke-type PM array for direct-drive applications. The key advantage of the proposed two-phase PMSMs is its superior flux-focusing effects, which greatly enhance the torque, benefiting from the whole machine configuration. To highlight the advantages of the proposed two-phase PMSMs, one three-phase PMSM and one two-phase PMSM with the conventional stator and winding configurations are adopted for comparison. All relevant machine characteristics, including the air-gap flux density, back electromotive force, and electromagnetic torque, are predicted by a 2-D finite-element method. Finally, one of the proposed dual-stator two-phase PMSMs is optimized to minimize cogging torque and torque ripples using the Kriging method and a genetic algorithm.