Investigation of saturation levitation force and optimization of permanent magnet guideway based on multi-seeded superconducting bulks model

Abstract

After more than 20 years of research, the superconducting maglev has advanced to the engineering research stage. In engineering applications, multi-seeded superconducting bulks have been widely used in high-temperature superconducting (HTS) maglev systems, but there remains a deficiency in terms of the theoretical model description of multi-seeded superconducting bulks. In this paper, the fully coupled, partially coupled, and uncoupled models of the multi-seeded superconductor are presented to simulate HTS multi-seeded bulk. Then, the levitation performance and trapped field of three kinds of HTS bulks were experimentally tested, revealing a saturation levitation performance on the permanent magnet guideway (PMG). Therefore, the levitation force and trapped field of HTS bulks with different critical current density are further studied by 3D simulation. Taking the 90% and 95% of the maximum levitation force as the benchmarks, the corresponding critical current density of HTS bulks are respectively 4.6 × 108 A m−2 and 6.1 × 108 A m−2. Further, a mapping coupled boundary method was adopted to automatic optimize the PMG to increase the levitation force above the PMG. After optimization, the levitation force under a unit of the permanent magnet is increased by 19%, while the maximum levitation force above multi-period Halbach PMG is increased by 9.23%. This study provides a general multi-seeded superconducting bulk simulation model and levitation force optimization method, which can serve as a reference for selecting suitable superconducting bulk.