| By using the flux pinning principle of high temperature superconductor bulk, high temperature superconducting (HTS) maglev technology can realize static stable suspension without active control in the appropriate external magnetic excitating condition. And this kind of excellent passive suspension technology, not only has the technical advantages of common magnetic levitation system, but also has such characters as simple structure, convenient application and high reliability. So this technology acquires more and more attention in the traffic field. Now, every HTS research group of the world maily focuses on HTS electromagnetic properties, occurring in the HTS specimens over permanent magnet (PM) or the permanent magnet guideway (PMG) moving along single direction of longitudinal, vertical or lateral direction respectively, or both vertical and lateral direction simultaneously. But in the actual operation conditions, HTS maglev train may experience different movement modes, such as arc curve movement in the horizontal plane when the HTS train enters into the curve from the straight guideway, train body lateral excursion movement (namely broken line movement) in the horizontal plane caused by lateral disturbances, and possible slant-line type movement in the vertical plane of the train tip edges when accelerating or decelerating. And the related reports of research on above different movement modes have not appeared yet. For the purpose of HTS maglev train practical application early, this dissertation does some basic experiment and theoretical research of the HTS bulk YBCO (YBa2Cu3Ox+1) maglev characters when bulks operate broken line type movement, slant-line movement and arc curve movement respectively above the PMG.Based on improving the high-temperature superconducting maglev measuremeant system (SCML-01) of Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), this dissertation constructs the HTS experiment platform of above three movement modes. With the composite movement of longitudinal and vertical axises, this dissertation studies the influence on levitation force with different bulk combination, slant-line angle representing the feature of slow and softly or suddenly increasing or decreasing the speed, and the movement times on field-cooling (FC) position; With the composite movement of longitudinal and lateral axises, this dissertation discusses the relationship of torque and both different lateral displacement and broken line type angle on FC position, and researches the relationship of torque and both the size of arc movent and slant angle of the PMG on FC position. Meanwhile, by introducing different movement control equation according to different movement modes and combing with Lorenz force formula and energy formula, this dissertation establishes the transient nonlinear model with multi-physical field coupling. And through studying the related theory of electromagnetic fields and superconductivity theory, this dissertation solutes the current density J within HTS bulk, by using the superconducting constitutive relation of HTS electromagnetic fields, namely the E-J constitutive relation model of flux flow and creep. By changing such parameters of HTS bulk as critical current density, moving speed, the size of moving path and PMG slanting angle, the dissertation completes the three dimensional numerical calculation of levitation force and guiding force with the comsol software, and further studies that the HTS internal factors and external conditions influence on maglev performance.The experimental and theoretical research results show that by improving HTS critical current density and external conditions, the HTS maglev performance can be improved in the case of above different movement modes. In addition, this dissertation research results will provide the test data and design consideration for engineering application of HTS maglev train. |
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