Researches On Modeling Simulation And Application Of Jointless Track Circuit

Jointless track circuit (JTC) is a key component of train control system. In addition to used for train detection, JTC also can convert JTC signal current in the rails to the induced voltage in Track Circuit Reader (TCR) antenna mainly through electromagnetic induction, so as to realize the track-train continuous information transmission of target speed for train. Thus it can be seen that the generation quality of the induced voltage in TCR antenna can greatly affect the safety operation of train. With the rapid development of the high-speed railway, the corresponding theoretical researches of this information transmission process need to be perfect. The simulation platform established based on mathematical modeling can provide the corresponding theoretical support and validation method for more study of adaptation of high-speed railway and the corresponding hot topics, such as process optimization and performance optimization. The major work of this paper is as follows.1. As to the transmitting process of JTC signal current, this paper puts forward the modeling and simulation method of JTC based on the six-port network, making up the insufficient that four-port network neglects earth leakage of JTC current. The content contains:transmission characteristic equivalent model of each component unit of JTC is built based on six-port network, the distribution model of the short-circuit current of JTC is modeled and the distribution of JTC current ahead of the leading wheels and axle of the locomotive is modeled.2. As to dynamic transmitting process of train control information between JTC and TCR antenna, namely electromagnetic induction process, this paper bases on the finite element electromagnetic field theory to complete the study. The content contains: building the finite element models of rails, compensation capacitors, TCR antenna, rails network, ballast bed and the leading wheels and axle of the locomotive based on the finite element electromagnetic field simulation software Ansoft Maxwell, setting material property, mesh and boundary conditions for the models, imposing excitation source of JTC signal, setting the motion simulation conditions of train and completing the simulation of dynamic electromagnetic induction process between JTC and TCR antenna under different speed conditions. The laboratory field data verify that the electromagnetic induction process model between JTC and TCR antenna based on finite element electromagnetic field theory agrees with the actual filed. 3. As to the problem of poor simulation efficiency of JTC finite element model, this paper puts forward a joint modeling and simulation method on information dynamic transmission process between JTC and TCR antenna based on transmission line theory and finite element electromagnetic field theory. This method firstly uses the JTC and TCR finite element models to determine the JTC-to-TCR range, then uses finite element to model the electromagnetic induction process between JTC and TCR antenna in the JTC-to-TCR range and model transmitting process of JTC signal out of the JTC-to-TCR range, finally calculates the JTC signal current at the demarcation point of the JTC-to-TCR range as excitation source output signal of JTC finite element model to complete the simulation of information dynamic transfer process between JTC and TCR antenna. The actual field application data verify that this joint modeling and simulation method has the advantages of accurate modeling, high simulation precision and simulation efficiency.4. As to the problem of lack of the amplitude and phase relational expression between JTC current and induced voltage in TCR antenna, this paper studies it from perspective of theory. The content contains:modeling the induced voltage in TCR antenna based on electromagnetic field theory, analyzing the contribution of the JTC current at different points to the induced voltage in TCR antenna, calculating the amplitude and phase relational expression between JTC current and induced voltage in TCR antenna from perspective of theory, verifying the correctness of the relational expression through lab experiment. Those research can provide theoretical basis for further qualitatively analyzing the influencing parameters of the information dynamic transmission process between JTC and TCR antenna, quantificational analyzing the influence rule of those influencing parameters and further optimizing the ground-to-train transmitting process.