I. Introduction
The superconducting levitation system has been intensively studied both experimentally [1] [2] [3] and theoretically [4] [5]–[8] to understand its physical properties and the prospects for application in many areas. Because of its passive and self-stabilizing features, possible applications of superconducting levitation systems include frictionless bearings for gyroscopes and energy storage flywheels, momentum wheels, high-speed machine tools, Mag-Lev trains and other levitated transport systems, etc.