Numerical Mutual Inductance Model Based on Spatial Fourier Decomposition for Racetrack Coils in EDS System

In the theoretical research on electrodynamic suspension (EDS) trains, the real racetrack superconducting coils with width and thickness which are onboard magnetic field coils are always equivalent to the rectangular coils. However, the magnetic field and electromagnetic forces' error caused by equivalence have not been explored yet. In this article, based on the Fourier model of the rectangular coil array magnetic field, a new Fourier model of the real racetrack coil array with width and thickness is established. The accuracy and effectiveness of the Fourier model are verified by the finite element simulations and the experimental results. On this basis, the optimal discrete model for racetrack coils with width and thickness is calculated. Besides, the electromagnetic forces in the three directions produce a nearly fixed proportion of deviation in the equivalence of racetrack coil to rectangular coil. The drag force decreases by 5%. The levitation and guidance forces increase by 4.3% and 6.1%. It has a profound impact on electromagnetic force calculation and dynamics analysis of EDS. The Fourier model for the real racetrack coil array in this article realizes more accurate calculations of EDS. Besides, it provides a more accurate calculation method for other systems including racetrack coils.