Double-layer quasi-Halbach guideway with NdFeB and ferrite materials for HTS Maglev

Abstract

In the high-temperature superconducting (HTS) pinning magnetic levitation system, permanent magnet guideways (PMG) need to be laid along the line as an essential part, and currently the guideways are all made up of NdFeB permanent magnets containing rare earth elements. To reduce the dependence on the rare-earth materials and to reduce the cost of the guideway, a double-layer double quasi-Halbach guideway has been designed and fabricated. The design is based on the finite element simulation using Maxwell equations. PMG model is based on the magnetic remanence and relative magnetic permeability of material, and bulks model is based on the power law model. The performance of the quasi-Halbach guideway is intermediate between that of the one-polar guideway and the Halbach guideway. Under the same conditions, a group of array of quasi-Halbach guideway has fewer permanent magnets and a larger vertical maximum magnetic field than a Halbach array. In this paper, a convex double quasi-Halbach multi-peak guideway has been designed by multiplexing NdFeB and ferrite material while taking PMG structure and NdFeB consumption into account. The new guideway utilizes 35% less NdFeB than the traditional Halbach guideway. Compared with Halbach guideway, there is no decrease in levitation capability at key place and only 25% decrease of guidance capability. The concept of double-layer quasi-Halbach multi-peak guideway significantly reduce the PMG's reliance on rare earth materials and then save a large amount of system expense.