Magnetic Gradient Levitation using Bulk Superconductors

我们研究了一种以高温块状超导体和软铁磁材料（如铁）为基本成分的磁梯度悬浮系统。进行了电磁场和力的测量和有限元分析，以发现其潜力和进一步研究的课题。(1)永磁式混合悬浮：测量放置在块状超导体之间的铁轨上的电磁力，证明了块状超导体对电磁力的稳定作用和恢复力的产生。较长的铁轨使电磁力特性不太稳定。(2)体超导磁梯度悬浮：由于超导体的临界电流密度有限，初始外加磁场的大小会影响电磁力的稳定性，但较低的外加磁场可以获得恢复力。还观察到钢轨长度对受力特性的强烈影响。电磁特性的数值分析：采用数值分析方法研究了电磁特性与块状超导体和铁轨的几何形态、超导体的有限临界电流密度和磁场的三维结构的关系。计算结果与实验结果吻合较好，对系统中的电磁现象有较好的认识。应用系统：当使用块状超导体的磁梯度悬浮应用于线性运输系统时，需要对移动方向的磁场分量进行屏蔽。磁轴承的应用具有很大的潜力。

We have studied a magnetic gradient levitation system that has high-temperature bulk superconductors and soft ferromagnetic materials like iron as essential components. Measurements of electromagnetic field and force and finite element analysis were carried out to find its potentials and subjects to be investigated further.1. Experimental study on electromagnetic characteristics(1) Permanent magnet type mixed-mu levitation : Measurements of electromagnetic force acting on an iron rail placed between bulk superconductors proved the stabilization effect of electromagnetic force by the bulk superconductors and the generation of restoring force. A longer iron rail made the electromagnetic force characteristics less stable.(2) Bulk superconducting magnetic gradient levitation : Although the magnitude of an initial applied field influenced the stability of electromagnetic force due to the finite critical current density of the superconductors, the restoring force was obtained for a lower applied field. The strong influence of the iron rail length on the force characteristics was also observed.2. Numerical analysis of electromagnetic characteristics : Dependence of electromagnetic characteristics on the geometrical configuration of bulk superconductors and an iron rail, the finite critical current density of the superconductors and the three dimensional structure of magnetic field were investigated by numerical analysis methods. The results agreed well with the experimental results and gave good understanding of the electromagnetic phenomena in the system.3. Application systems : When the magnetic gradient levitation using bulk superconductors is applied to a linear transportation system, the shielding of the magnetic field component in the moving direction is required. Magnetic bearing application has a large potential.