Analysis And Research Of Axle Counter Electromagnetic System

Axle counter is one of the most important railway signaling devices, indetecting the train wheels and determining the clearance or occupation of a tracksection. Electromagnetic system as a core part of the axle counter directlydetermines the results of wheel detection. Analysis and research on theelectromagnetic system of axle counter especially calculating the distribution andvariation of its magnetic field correctly forms an important basis for developmentand optimization of the axle counter.In this paper, we first build the mathematical model of the electromagnetic fieldof the axle counter and derive its constraint equations. Then according to thejudgment condition of quasi-static field, the property of axle counter’s magneticfie ld is analyzed. On this basis, working principle of the axle counter is describedusing fie ld equations. And then vector magnetism location is introduced anddifferential equations of the magnetic field around axle counter are derived.Secondly, sensing devices of the axle counter is designed including the designof excitation coil and induction coil concerning their materials, sizes, electricalparameters as well as their mounting position and orientation. And the installationmethod of the sensing devices on the rail is developed. Then parameter informationof the core in the excitation as well as size parameters of the rail and wheel areprovided.Then, design scheme of the sensing circuits is proposed. The sensing circuitconsists of three parts by function: the power supply circuit, the excitation circuitand the receiving circuit. The power supply circuit is realized using DC-DC modules.The excitation circuit is divided into an oscillation circuit, a power amplificationcircuit, and a series resonant circuit. A parallel resonant circuit for frequencyselection and a amplification circuit compose the receiving circuit. Principle of eachunit circuit is analyzed and their parameters are calculated.At last, magnetic fie ld around the axle counter is studied. A three-dimensionalsimulation model of the axle counter is established. Distribution and variation rulethe magnetic field around the axle counter is analyzed using the calculation results.Then the effect of coil orientation on magnetic field is studied. Experiment platformis built to verify the simulation results. Experimental results suggest that simulationresults meet the accuracy requirements for axle counter development.