Optimization of the Combined Propulsion, Levitation and Guidance Coil in Superconducting Maglev System

A more favorable maglev coil system was proposed for the combined propulsion, levitation and guidance (PLG) system. This coil system combines the functions of propulsion, levitaion and guidance of vehicle into one coil. This paper discribes the optimization of coil dimensions for minimizing the apparent power input for propulsion. The coil dimensions are chosen so that the levitation force, the lateral stiffness and the rolling stiffness satisfy necessary values and that the propulsion force is balanced with the running resistance, including the magnetic drag force. Ground coils are assumed to be arranged with either 120 degree pitch or with 60 degree pitch in a single layer. By using numerical examples, it becomes clear that the apparent power input has a minumum value at a certain value of the pole pitch. For example, the optimum pole pitch in the case of 120 degree coil pitch is a little shorter than that of the 60 degree coil pitch. Dependence of the optimum pole pitch on such parameters are investigated. These include mmf and height of the on-board superconducting coil, the cross sectional area of the ground coil, the feeding section length and the mechanical air gap.