Semianalytical Calculation of Superconducting Electrodynamic Suspension Train Using Figure-Eight-Shaped Ground Coil

Superconducting electrodynamic suspension (EDS) train has the unique advantages of excellent levitation and guidance stabilities, large levitation gap, and so on. All of these merits make it a promising candidate for the future ultrahigh-speed transportations. In order to explore the dynamic characteristics of the EDS system with a figure-eight-shaped coil (ground coil), this article transforms the complex electromagnetic field coupling between the superconducting magnets and ground coils into a reduced circuit relationship based on the dynamic circuit theory. Meanwhile, the motion characteristics are introduced to establish the field-circuit-motion-coupled model. In this article, a faster and more convenient semianalytical method was proposed to solve mutual inductance. First, the dynamic circuit model of a single-sided figure-eight-shaped null-flux EDS system was established. The magnetic coupling calculation was carried out between the onboard superconducting magnets and ground coils by a semianalytical method. Furthermore, the time-step iteration method was utilized to solve the induced current governing equation of the ground coil under different operating conditions. The energy method was employed to find the transient solution of the levitation force, guidance force, and drag force. Second, the field-circuit-motion-coupled model was validated by the experimental data of MLX01 on the Japanese Yamanashi testline. To investigate the influence upon the suspension and guidance caused by the different connection types of figure-eight-shaped coil, a cross-connected EDS train dynamic circuit model was built. Finally, based on the field-circuit-motion-coupled model, the essential parameters affecting the stability of the system were explored, and the characteristics of the system when vertical or lateral displacement occurs were calculated and analyzed. The achievements of this article can provide a reference for the design of the EDS train for future even higher speed transportation.