Improved Analytical Modeling of Induced Currents in Null-Flux Coils for Electrodynamic Suspension Systems

Electrodynamic suspension (EDS) systems are regarded as a promising solution for next-generation high-speed rail transportation. Under high-speed operating conditions, accurate prediction of electromagnetic coupling and induced current behavior is essential. This paper presents an improved analytical model for induced current prediction in null-flux coils of superconducting EDS systems. The model is established based on the spatial harmonic method and dynamic circuit theory, with end-effect compensation and impedance angle modeling incorporated to improve accuracy under high-speed conditions. The proposed analytical model is validated with finite element simulations and the experimental data from the Yamanashi maglev test line. Compared with existing analytical models, the proposed model achieves substantially better agreement with finite element simulation results. The developed analytical framework provides a reliable modeling basis for subsequent generator coil parameter optimization and system-level performance analysis.