The longitudinal inhomogeneity of applied magnetic field above PMG

The inhomogeneity distribution of applied magnetic field along longitudinal direction above permanent magnetic guideway (PMG) reduces the levitation stability of the high-T-c superconductor (HTS) maglev system. In order to explore and reveal the inhomogeneity distribution of magnetic field along longitudinal direction above PMG and its causes, as well as its influence on the static levitation force of YBa2Cu3O7-x (YBCO) bulk, the theoretical model is built by COMSOL Multiphysics to simulate the longitudinal distribution of magnetic field above the PMG and the static levitation force of the YBCO bulk. Furthermore, a three-axis motion experimental platform is designed and built to measure the longitudinal distribution of magnetic field, upper surface profile of the PMG and static levitation force of the YBCO bulk by the corresponding testing equipment. It is shown in this study that, in the assembly processing of PMG, the surface of permanent magnet (PM) is sloping along the longitudinal direction, and there are gaps and damage between adjacent PMs. The simulation and experimental results show that these multiple defects lead to inhomogeneity distribution of magnetic field along the longitudinal direction and the attenuation at the joints, resulting in the difference in the static levitation force of YBCO bulk at different longitudinal positions of the PMG. The results could provide a reference for the further design and practical application of higher performance PMG.