Research On Characteristics Of High-temperature Superconducting Hybird Maglev With Tape And Bulk

Maglev is an important development direction of rail transit.High-temperature superconducting(HTS)maglev has the advantages of levitation/guidance self-stabilization,non-active control,reliable structure,and high-speed.It’s one of the most revolutionary frontiers in the field of rail transit.At present,the load capacity of HTS maglev is above 1 t/m.In order to make the HTS maglev more valuable,the vital research content is to find a levitation unit structure with heavy load and stable dynamic performance.The YBCO bulk has been the main choice of levitation unit.Recent years,with the rapid development of the coated conductor manufacture technology of YBCO tape,more and more researchers try to use coated conductor tapes to replace bulk superconductors as the levitation unit.The study of HTS hybrid maglev with tape and bulk isn’t carried out now.The advantages of tapes compared to bulks are higher critical current density(J_c ),higher mechanical strength and flexible in geometry.The research would be very meaningful,if we could combine the advantages of tape and bulk together.In this thesis,the J_c anisotropy of stack tape has been studied.The J_c equivalent anisotropy is proposed.The influence of the equivalent anisotropy property on the levitation/guidance force and trapped field has been experimental obtained.Moreover,the equivalent anisotropy value w has been calculated used a phenomenological model.The results showed that the J_c anisotropy of the stack tape is stronger than that of the bulk,the w is 11.4.The magnetic coupling effect between superconductors has been studied.By calculating and experiment,it’s concluded that,the superconductor could be affected by the other superconductors through the magnetic field.But due to the strong magnetic field of permanent magnet guideway(PMG),the magnetic field coupling effect could be ignored.It could realize1+1=2,if we combine several superconductors together.A new geometry hybrid with tape and bulk are proposed,which we called“Stack Hybrid”.The comparison of levitation/guidance efficiency between bulk and stack tape has been done.The result indicates that efficiency of stack is about half of that of the bulk.The levitation/guidance force property of it has been experimented.The results showed that it could improve the levitation/guidance force with the increase of stack thickness.The optimization researches have also been done.A new geometry hybrid with tape and bulk are proposed,which we called“Loop Hybrid”.This geometry has weaker J_c anisotropy.The levitation/guidance force property of it has been experimented.The results showed that it could improve the levitation/guidance force with the increase of stack thickness.The study of HTS hybrid maglev with tape and bulk can effectively improve the load of HTS maglev vehicle,provide a variety of new options for levitation unit,and promote the development of HTS maglev vehicle technology.