| With the continuous development of high-speed railway in China,the train speed degree is constantly rising,which puts forward higher requirements for its braking technology.At present,the air-electric compound braking used in high-speed trains belongs to the adhesive braking,which can hardly meet the braking requirements of higher speed trains.Linear Eddy Current Brake(LECB)is a non-adhesive Brake,which has the advantages of small wear,no noise,clean and environmental protection.It is expected to be applied to new EMUs with higher speed in China.Therefore,it is of great significance to study the electromagnetic characteristics and braking performance of LECB system and to analyze the feasibility of its application in China’s high-speed EMUs for promoting China’s LECB system design and engineering application.The main research contents of this paper are as follows:Firstly,the working principle of LECB and its working process under different working conditions are studied,and the eddy current on the rail surface is equivalent to a virtual electromagnet to avoid introducing the empirical coefficient when considering the eddy current demagnetization effect.The mathematical model of LECB system based on virtual electromagnet is established,and the calculation formula of eddy current braking force is obtained.Secondly,the LECB system is simulated by finite element method to analyze the eddy current density on rail surface and magnetic induction intensity of eddy current brake device,air gap and surrounding space under two working conditions of common braking and emergency braking.In addition,the effects of train speed,air gap and excitation current on eddy current braking force are analyzed.The simulation results are compared with theoretical results to verify the correctness of the model.Thirdly,according to foreign LECB related line tests,axle counter is susceptible to interference from LECB system,which leads to counting errors and endangers driving safety.Therefore,the "field-path" co-simulation model of axle counter and LECB system is established by Maxwell and Twin Builder,co-simulation is conducted to analyze the interference of LECB system to axle counter under typical working conditions.Finally,in order to avoid the interference of LECB system to axis counter,a electromagnetic protection method for axis counter based on Kriging method and particle swarm optimization algorithm is proposed.Firstly,take the installation angle of the two coils of axle counter as variables,based on the kriging method to establish the induced voltage of the device receiving coil change model.Then a multi-objective particle swarm optimization algorithm based on Beetle Antennae search is designed to conduct multi-objective optimization for the induced voltage change model,and the optimization results were verified in the simulation model.The simulation results show that adjusting the installation angle of the two coils can reduce the interference of LECB system to axle counter in the most economical and effective way.In this paper,the electromagnetic characteristics and braking performance of LECB system are studied by combining theoretical research and simulation analysis.At the same time,the electromagnetic interference of LECB system to typical track signal equipment is analyzed and gives the electromagnetic protection measures.The results can provide a theoretical basis for the design of LECB system and the feasibility of its application in China’s high-speed EMUs. |
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