Study on the Characteristics of the Maglev Electromagnet Considering the Magnetic Field Induced by Eddy Current

Abstract

The rails of the medium-low speed maglev system are entirely manufactured by roller milling, and eddy current in the rail can be induced when relative movement between the electromagnet and the rail manifests. The eddy current reduces the magnetic field in the air gap between the electromagnet and the rail, which, as a result, decreases the levitation force; and higher speed will cause more levitation force lost. Moreover, the eddy current produces a drag force which is opposite to the propulsion force generated by the linear inductive motor. In this paper, based on the electromagnetism, the formulae for the levitation force and the drag force of the electromagnet are deduced when the eddy current in the rail is taken account. Simulations based on the model of the maglev vehicle on the Tangshan maglev test line are also performed. The results indicates that the levitation force is significantly affected by the eddy current in the rail, and when v = 200 km/h, the levitation force of a single electromagnet is reduced by 35.6%; meanwhile, the drag force increases dramatically as the speed increases, but when the speed exceeds 100 km/h, the drag force stops increasing, and it equals 2.28% of the stationary levitation force.