Research On The Electromagnetic Characteristic Of Rail-switch Snow-melting System

With the rapid development of high-speed railway and the raising speed of locomotive, the traffic safety should be taken into serially consideration. Especially in the north in winter, the icing problem is prominent. If the ice frozen in the rail-switch cannot be melted and eliminated promptly it will make the rail-switch closely connected, which is a significant hidden danger in the high-speed railway transportation safety. Due to the low efficiency, high consumption, short duration as well as complex installation of the existing snow-melting system a new and better one is urgently needed.This paper aims to research on the EM characteristic of a new snow-melting device which was installed outside the rail-switch and directly heat the railroad surface by eddy current to melt the snow and ice. The new device does not destroy the railroad structure and has no affection on the basic railroad. Compared with the existing device the new one is high efficiency and low energy consumption It is incited by the current ranging from5A to more than a dozen A at3000kHz, but the effect of its EM field to the BTM system is unknownBasic principles of effects of heating are introduced at first. EM character of eddy current base on Maxwell equations and FEM including liner&nonlinear material and2-D&3-D eddy current filed are analyzed. As for the analyzing of dimension EM field the analyzing method of classical dipole antenna and loop antenna were taken as references. The heating copper loop was considered as many concentric loop antennas. The field in any site was the vector superposition of all copper loops. Then the snow-melting system was simulated by two kinds of software and their results nearly coincided. The simulation focus on the influence of the shape of the copper loop, the extinction current, frequency and the distance between the snow-melting system and the railroad. Meanwhile the curve of the increasing amount of the loop inductance was obtained. Then some certain planes was chosen in order to monitor it’s attenuation of the near field region. Finally the conductive EMI caused by inverter circuit was analyzed and several types of filter and it’s designing method was introduced then the suppression analysis of the filter was given according to the simulation...