Design Optimization of Improved Halbach Tubular Permanent Magnet Linear Synchronous Motor with Less Permanent Magnet

Abstract

To reduce the permanent magnet (PM) usage and cost, the improved Halbach tubular permanent magnet linear synchronous motor (IH-TPMLSM), which has unequal thickness of the radial and axial magnetized PMs located in the mover, is developed in this paper. Taking the maximum average thrust as the optimization objective, the single-step optimization method based on sensitivity analysis is used to optimize motor under the same current density by finite element (FE) analysis. The influence of the pole-pitch τ on the detent force is analyzed. According to the comparison of optimized TPMLSMs, the results show that when pole-pitch τ = 30.5mm and the full-pitched winding disposition τs = 31.5mm, the detent force is reduced by 55.87%. Finally, the open-circuit back EMF, air gap flux density, the thrust of the IH-TPMLSM and the quasi Halbach TPMLSM (QH-TPMLSM) are compared. The quantity of PMs of the IH-TPMLSM is 15.27% lower and the average thrust is 4.01% higher than that of QH-TPMLSM. Meanwhile the thrust ripple is reduced by 36.12%.