Study on the Slot/Pole Combination Influences to the Thrust Performances of the Linear Permanent Magnet Vernier Machines

The slot/pole combination influences to the thrust performances of the linear permanent magnet vernier machines (LPMVMs) are studied in this paper. The slot/pole combination influences of LPMSMs and LPMVMs will be firstly analyzed in analytical equations. Then, the thrust performances of the conventional LPMSMs, fractional slot concentrate windings (FSCW) LPMSMs, LPMVMs will be calculated using the finite element method (FEM) and compared with each other. The mover end length compensation method is adopted to reduce the end effect of the LPMSMs, and the residual detent force after the end length optimization is adopted to evaluate the noload thrust performance of the machine. The comparison results show that the LPMVMs have the better performances than the conventional LPMSMs and FSCW LPMSMs. A LPMVM with a novel 12/14 slot/pole combination, which has larger thrust density compared to the conventional LPMSM and lower thrust ripple compared to the high pole ratio LPMVM, is proposed in the paper.