The Levitation Characteristics of HTS Bulks Under the Effect of Bridge Deflection Coupled with Random Excitations

High-temperature superconducting (HTS) maglev is a kind of new maglev structure mode. In actual operation, due to the arrangement and assembly error of the magnet of permanent magnet guideway (PMG) as well as the loss and material stripping during operation, superconductive bulks are always in a state of random fluctuation. In order to study the influence of the irregularity of PMG and bridge deflection on the levitation characteristics of superconductors, the model using the E-J power law model is established in COMSOL Multiphysics 5.6, and the random lateral and vertical irregularity coupled with the bridge deflection is added to PMG for research. The results show that the effects of random excitation and bridge deflection on levitation characteristics are coupled and interact with each other. The vertical excitation and bridge deflection affect the guidance force of dewar while the lateral excitation also affects the levitation force. The levitation characteristics of dewar fluctuate with the fluctuation of random excitation. In the condition without excitation and bridge deflection, the levitation force of the dewar used in this paper is maintained at 3.455kN, the guiding force is - 84.987 N, and the average current density is 1.971MA/m(2). The levitation characteristics of dewar will fluctuate with the fluctuation of random excitation. When the bridge deflection is added, the levitation force, guidance force, and average current density of dewar will increase with the increase of bridge deflection. Taking the variation of levitation force as an example, the maximum suspension force is maintained near 5.572kN when the bridge deflection is 2 mm, 8.358kN when the bridge deflection is 4 mm, and 11.858kN when the bridge deflection is 6 mm regardless of random excitation. There is a critical point of levitation force when the dewar is suspended on PMG. If the gap between dewar and PMG exceeds the critical point, the average current density will reverse and the levitation force will be negative. The critical point of the model used in this paper is around 21 mm above the PMG. These results provide a reference for the working condition prediction of the HTS Maglev train.

Automated summary

This study establishes a model using COMSOL Multiphysics 5.6 to investigate the influence of irregularities in permanent magnet guideways and bridge deflection on the levitation characteristics of high-temperature superconducting (HTS) maglev trains. The results show that the irregularities and bridge deflection have a coupled effect on levitation characteristics, and the levitation characteristics fluctuate with random excitation.