Analysis of Dual Three-Phase Permanent-Magnet Synchronous Machines With Different Angle Displacements

In this paper, a novel nonconventional angle displacement (i.e., 15°) between two sets of three-phase windings is proposed for dual three-phase permanent-magnet (PM) machines. First, all feasible angle displacements between the two three-phase winding sets for various slot/pole number combinations of dual three-phase machines are discussed in general. Then, an in-depth investigation is carried out on a 24-slot/10-pole dual three-phase PM machine as an example covering various electromagnetic performances. The investigation shows that under healthy and three-phase open-circuit conditions, the proposed 15° configuration has a comparable electromagnetic performance to the 30° configuration, and a better performance than the 0° counterpart. Furthermore, under three-phase short-circuit (SC) condition, the proposed 15° configuration has the lowest SC current, smallest braking torque, and the best PM demagnetization withstand capability. Finally, three prototype 24-slot/10-pole surface-mounted PM machines are built and tested to verify the theoretical analyses.