Characteristic Analysis of HTS Levitation Force With Various Conditions of Ground Conductors

In this paper, the characteristics of the high temperature superconducting (HTS) electrodynamic suspension (EDS), which is influenced by the conditions of the ground conductor, were analyzed by using numerical simulation and the modeled simulator. The HTS magnet was optimally designed with numerical simulation considering the structure of the magnet and the various conditions of ground conductors. The induced eddy current of the ground conductor forms the levitation force of electrodynamic suspension. Because the eddy current is proportional to the flux linkage and its change rate to time, the levitation force is influenced by the condition of the ground conductor. The structure of the HTS levitation magnet was designed for the maximum magnetic flux linkage and the minimum ground conductor size. The levitation force of the HTS magnet influenced by ground conductor condition was calculated with numerical method and measured in the modeled simulator. The modeled simulator is composed of an HTS magnet, a rotating wheel, a motor, the force measuring devices, and a supporting structure. The inductance of the HTS magnet was 279.4 mH and the critical current of the HTS magnet was successfully estimated. It was recommended that the normal magnetic flux density in the ground conductor should be greater than 0 T. The levitation force and the drag force were proportional to the square of the HTS magnet current. The levitation force became saturated after 20 m/s and the drag force became saturated after 60 m/s.