Electromagnetic and dynamic characteristics of HTS maglev systems under rotating magnetic fields: Experiments and modeling

Abstract This study investigates the electromagnetic coupling dynamics characteristics of high-temperature superconducting (HTS) maglev systems under rotating magnetic fields through quasi-static and dynamic experimental characterization combined with numerical modeling. Two experimental protocols are designed: (1) quasi-static force measurements under constrained-rotation HTS bulks to quantify electromagnetic force and torque components; (2) dynamic response measurements tracking yaw angular displacement during free vibration to extract rotational damping and natural frequencies. An improved H-formulation model simulating translational-rotational composite fields is proposed. Finite element simulations and experimental results demonstrate that rotating magnetic fields induce significant nonlinearities in electromagnetic force, stiffness, damping and natural frequencies. Key findings reveal the dependences of the electromagnetic force on the rotation angle and the lateral displacement for the HTS maglev, including the differences in the bulk configurations. Dynamic tests show that releasing yawing rotational degree of freedom (DOF) reduces natural frequency (from 3.23 Hz to 3.04 Hz) and increases rotational damping (from 0.684 N·s/rad to 1.602 N·s/rad), with excessive rotational freedom destabilizing the system by displacing it from equilibrium. These results elucidate the interplay between electromagneticmechanical coupling stability, offering critical insights for studying HTS maglev systems under multi-excitation conditions in addressing curve and turnout trafficability challenges.