The Relationship of Magnetic Stiffness Between Single and Multiple YBCO Superconductors over Permanent Magnet Guideway

Abstract

For YBCO bulk levitating over a permanent magnet guideway (PMG), the magnetic stiffness is connected directly with the pinning properties of the measured sample. An experimental setup has been built to investigate the vertical and lateral magnetic stiffness of five high-temperature superconducting (HTS) bulk arrays over a PMG by two methods: the additive method, i.e., calculating the summation of the measured magnetic stiffness values of each HTS bulk in the array; the direct method, i.e., measuring directly the magnetic stiffness of the HTS bulk array. From the experimental results, it is found that the resultant magnetic stiffness of the HTS bulk array composing of multiple YBCO bulk is related with the magnetic stiffness of each individual single bulk, but the additive method does not predict the magnetic stiffness of the array very well because of the interaction between adjacent HTS bulk. The resultant magnetic stiffness of the HTS bulk array is less than the summation magnetic stiffness of each single HTS bulk. One numerical method is used to calculate the magnetic stiffness for comparing with experimental results. The results may be helpful to the design and optimization of the superconducting magnetic levitation system.