Motion characteristics of a self-driven HTS bulk maglev under the composite magnetic field

High temperature superconducting (HTS) maglev has the advantages of levitation-guidance integration and low magnetic resistance due to pinning effects. Currently, most HTS maglev systems adopt linear motors for propulsion, requiring the installation of the mover on the maglev vehicle and the stator on the track separately. It is potential to establish the composite pancake coil magnetic field based on permanent magnet guideway (PMG), which can bring HTS bulks the original levitation and guidance force generated and driving force. Based on the self-development micro levitation force test device, the paper explores the feasibility of using coils to drive HTS bulks. At a working height (WH) of 12 mm and a coil current of 15 A, the maximum driving force can reach 0.2 N. The driving force can be increased by reducing the WH or increasing the field cooling height (FCH). Based on the COMSOL Multiphysics software, the three-dimensional finite element simulation model of HTS bulks combined with the motion equation was established. Qualitative analysis of the free movement characteristics of the HTS bulk driven by the coils was performed, and the differences between different current directions were compared. In addition, the paper built a driving principal model to analyze the movement characteristics of HTS bulks driven by coils. Consistent with the simulation results, the levitation height increases, and positive pitch angle occurs when driven by the positive current, while the levitation height decreases, and negative pitch angle occurs when driven by the negative current.