Combination In The Form Of Its High-temperature Superconducting Bulk And Permanent Magnet Levitation Force Investigated And Applied Research

High levitation force and good self stability of REBCO (RE=Y,Gd) bulk superconductors make it possible for applications such as superconducting magnetic bearings and levitation transportation systems etc.. These applications are based on the levitation force characteristics between the superconductors and magnets, so it is very important for us to investigate the levitation properties between superconductors and magnets. In this paper, the effect of magnet configurations on the levitation force of REBCO bulk superconductor have been investigated and interpreted based on the theory of superconductivity, and a small maglev model has been designed and constructed; the main results are as following:A levitation force and magnetic field distribution measurement system was used in this work. In order to improve the accuracy of the measurement system, a filtering circuits and a hybrid filtering algorithm have been designed and applied; the results show that the quality of signal to noise ratio has been effectively improved after the modification. A levitation force measurement device in three dimensions improved. The levitation force, between a single domain GdBCO bulk superconductor and a cylindrical permanent magnet, has been investigated in coaxial symmetry at zero field cooling state. The results show that the levitation force has an obvious hysteresis and directly dependent on the applied magnetic field, and higher levitation force can be obtained by optimizing the magnetic field during the measurement process. It is also found that the repulsion force increases and the attractive force decreases when the field-cooling height between the single domain GdBCO bulk superconductor and permanent magnet increases. The results are well interpreted based on the Bean model.The effect of magnet configurations on the levitation force of a single domain GdBCO bulk superconductor has been investigated. For small cubic permanent magnets(less than the size of the GdBCO bulk), it is discovered that the levitation force is closely related with the number and configuration of cubic permanent magnets, for a given number of cubic magnets, the fewer the cubic magnet number and the magnetic poles, the higher the levitation force of the superconductor; For small bar magnets(the width and height less than the length, but the length near to the size of the GdBCO bulk), It is found that reasonable configuration of assembled bar magnets(ABM) can produce higher levitation force, three bar magnets can generate higher levitation force than that of two bar magnets. The levitation force and guidance force between a bulk superconductor and assembled bar magnets has also been investigated and interpreted. It is found that the higher levitation force is obtained in the HTS-((?)-PM↑-(?)) configuration, and larger guidance force is obtained in HTS-(PM↓-PM↑-PM↓) configuration. Effects of additional permanent magnet configuration on the levitation force of a single domain GdBCO bulk superconductor have been investigated with a cylindrical permanent magnet in their coaxial configuration at liquid nitrogen temperature, the magnetic pole N of the cylindrical permanent magnet is directed to the GdBCO bulk superconductor in their coaxial configuration. It is found that the larger levitation force is obtained in the PM↓-((?)-HTS-(?)) configuration, and smaller levitation force is obtained in the PM↓-(PM↑-HTS-PM↑) configuration. The width effects of the iron for condensing magnetic field on the levitation force indicate that reasonable iron width is helpful to enhance the magnetic flux density and improve the levitation force of the superconductors.The effect of magnetization methods with additional permanent magnet on the magnetic field distribution and levitation force of single domain GdBCO bulk superconductor have been investigated with a cubic permanent magnet in their coaxial configuration at liquid nitrogen temperature. It is found that:if the N pole of the cubic permanent magnet, during the levitation force measurement, is placed above the GdBCO bulk superconductor and in downward direction, the maximum levitation force can be improved, when the N pole of the additional cubic permanent magnet points to upward and stick together to the bottom of the GdBCO bulk. The maximum levitation force can be improved (or reduced), when the GdBCO bulk superconductor is closely placed below and magnetized by the additional cubic permanent magnet with N pole in upward(or downward) direction, and removed away after the magnetization.The effect of lateral magnetization position(x) between a cubic permanent magnet and GdBCO bulk superconductor at fixed height on the levitation force has been measured, it is found that the largest (or smallest) maximum levitation force is obtained at x=0when the magnetic poles N of the magnetized GdBCO bulk is in a direction opposite (or parallel) to the magnetic pole N of the permanent magnet used for measurement.A hybrid levitation system of permanent magnet-permanent magnet levitation (PM-PM) and high temperature superconductor-permanent magnet levitation (HTS-PM) has been also investigated; it is found that the levitation force and stiffness of the hybrid system can be modified by the combination of HTS-PM and PM-PM levitation.A small HTS maglev model has been designed and constructed for the demonstration of interaction properties between the high temperature bulk superconductor and different magnet configurations, which can demonstrate the normal, instability, tilting, jumping, shocking, or stopping phenomena of the maglev gestures.