Performance Comparison of Tubular Flux-Switching Permanent Magnet Machines Using Soft Magnetic Composite Material and Hybrid Material Magnetic Cores

The magnetic core of a conventional tubular flux-switching permanent magnet machine (TFSPMM) is made of axially laminated silicon steel sheets. The laminated direction is consistent with the motion direction of the mover. According to the flux-switching principle, a large amount of eddy current loss will be generated when the alternating flux passes through the silicon steel sheets vertically. The soft magnetic composite (SMC) material is magneto-thermal isotropy and has low eddy current loss, which can be used in TFSPMM. However, the permeability of SMC is much lower than that of silicon steel sheets, and the hysteresis loss is large at low frequency. When the two materials are used as the hybrid material magnetic core in the machine, their respective advantages can be used to improve the thrust force of the machine and reduce core loss. In order to study the effect of SMC core and hybrid material magnetic core on the machine, the performances of TFSPMM with different kinds of cores are calculated and compared by finite element method (FEM), including magnetic density distribution, permanent magnet (PM) flux linkage, back-electromotive force (EMF), inductance, detent force, thrust force and core loss. Finally, a prototype machine with hybrid material magnetic core is made and experimental verification is carried out.