Dual-Stator Line-Start Vernier Permanent Magnet Synchronous Machine

Vernier permanent magnet (VPM)machines have attracted more and more attentions due to their desirable features of high torque density. However, nearly all the proposed VPM machines are driven by converters. In this paper, two methods to acquire self-starting ability for VPM machine are proposed. The inverter is omitted due to the self-starting capability of the proposed topology. Firstly, a consequent-pole line-start vernier permanent magnet (LSVPM)machine is analyzed to clarify traditional method by embedding squirrel cage in the rotor is not suitable for VPM machine. Then the structure and circuit of the dual-stator line-start VPM (DSLSVPM)machine is proposed. The decoupling of starting performance and steady performance is analyzed. The PM braking torque is eliminated during the whole starting process. Finally, the starting and steady performance is validated by finite element analyzes (FEA). The torque density is increased 80% compared with conventional line-start PM machine.