Investigation of Line-Start Permanent Magnet Vernier Machine With Different Rotor Topologies

As a new type of flux modulation machine, line-start permanent magnet vernier machine (LSPMVM) has drawn increasingly more attention. Thanks to the rotor starting winding; its self-starting capability can be acquired without applying the inverters. As a result, the system reliability has been improved and cost can be decreased, which is promising for industrial applications, such as pumps and fans. To extend the family of LSPMVMs and select the preferable topologies meeting different requirements, four LSPMVMs, including V-shaped LSPMVM, consequent-pole U-shaped LSPMVM, dual-stator spoke LSPMVM, and consequent-pole surface-mounted permanent magnet (SPM) LSPMVM, have been proposed in this article. The steady-state performance, starting and synchronization capability are comprehensively analyzed and compared, where the regular commercial line-start permanent magnet synchronous machine (LSPMSM) is used as a counterpart. It is found that all the proposed LSPMVMs can acquire the higher torque density. Especially, the V-shaped LSPMVM and consequent-pole U-shaped LSPMVM have the highest torque density, while the consequent-pole SPM LSPMVM can be a better candidate where the low cost is desirable. Finally, the prototype of V-shaped LSPMVM has been manufactured, where experimental results match well with finite element analysis (FEA).