Characteristics of Guidance and Levitation Forces between HTS Magnets and Conductive Tubes for Hyperloop

초록

High-temperature superconducting (HTS) magnets combined with linear synchronous motors (LSM) and electrodynamic suspension (EDS) are considered as one of the most suitable technologies for Hyperloop. However, HTS magnets on pods generate strong magnetic fields, inducing eddy currents on conductive tubes when pods undergo movement through conductive tubes. The induced eddy currents affect HTS magnets, leading to electromagnetic (EM) drag, guidance, and levitation forces on the pods, thus reducing the propulsion efficiency and dynamic stability of pods. This study continues the existing research on EM drag forces between HTS magnet and tube for Hyperloop by comprehensively analysing the EM guidance and levitation forces between HTS magnets and conductive tubes. Importantly, the full-scale 3D FEA simulations show that different steel tubes, such as AISI 1010 and Hi-Mn steels, should be adopted, depending on the operating velocities, v, to avoid attractive forces in the guidance direction decreasing horizontal stiffnesses, kx. For example, Hi-Mn tubes generating repulsive guidance forces are adopted when v is below 300 km/h while AISI 1010 tubes are used when v is over 300 km/h to minimize the construction cost of vacuum tubes and the decrease in kx. Moreover, levitation forces generated between HTS magnets and conductive tubes are nearly 0.5% of the EDS forces of pods, i.e., 200 kN over.