Numerical Simulations on the Vertical Dynamic Characteristics of High-Temperature Superconducting Bulk

High-temperature superconducting (HTS) maglev, owing to its unique self-stability characteristic, has a wide range of application prospect in flywheel energy storage, magnetic levitation bearing, rail transportation, and other fields. As the important foundation of the engineering application, researches on the dynamic characteristics of HTS maglev have attracted more and more attention. As most of existing models adopted the power exponential function to approximately fit the relationship between the force and displacement, which can only qualitatively analyze the dynamic characteristics of HTS maglev, this paper employs the flux flow and creep model to deduce a 2D H formulation of the HTS maglev system to make up for this deficiency. Moreover, related experiments were also carried out to validate the accuracy of this simulation model and comparisons with other previous models have been achieved. The results prove that the simulation model can reduce the calculation time still with a good convergence. Then, an electromagnetic-thermal-force multiphysics coupling model was established to analyze the dynamic characteristics, especially the levitation height drift of an HTS bulk above the permanent magnet guideway. Results indicate that when the superconductor has an initial velocity that causes disturbance at the working position, vibration and drift phenomena will occur, and the vertical levitation drift also grows as the velocity increases. The simulation results also show that resonance will occur if the excitation frequency is close to the HTS maglev system's resonance frequency, and a strong "beat" phenomenon will occur if the excitation frequency is close to twice the main vibration frequency of the system. Additionally, the HTS maglev system shows good anti-vibration ability on the relatively low-frequency region as well as the high-frequency region, which proves that it can be well applied to the rail transportation field. All results could be supported as references for the design of HTS maglev systems and its future application.