Research On Guidance Force Of High Temperature Superconductor YBCO Bulks Over The Permanent Magnet Guideway

It was found that a bulk high-temperature superconductor can stably levitate above or suspend below a permanent magnet soon after the discovery of high-temperature superconductor. Based on the intrinsic magnetic flux pinning, this new and simple magnetic levitation yields several possible applications, among which is the high-temperature superconducting magnetically levitated train. The guidance performance is of vital importance for a magnetically levitated train. Most of the research, however, is concentrated on the levitation performance of the system. The present thesis considers the guidance performance of a superconductor when it moving quasi-statically above the permanent magnetic guideway. With different cooling conditions, the guidance forces of superconductors of different geometrical sizes are measured. The superconducting magnetically levitated vehicle is simplified as an infinite-long system whose cross section is considered. A model based on the method proposed by L. Prigozhin is built to describe the force the superconductor may experience when moving above the guideway. Also considered is the dependence of the guidance performance of the superconductor upon such elements as geometrical and current parameters of the system, the movement of the superconductor. Comparison between the experimental and theoretical results indicates the effectiveness of the method utilized in the thesis. As an application of the model, the curve-negotiation performance of a board-like superconducting magnetically levitated system is considered. It is pointed out that more attention should be paid to the reversibility of the movement of the superconductor above the guideway.