| Maglev trains have significant advantages,such as high safety,high reliability,low noise,and low power consumption,and offer a promising future for the development of urban rail transport in China.However,there are also potential safety hazards associated with their operation.Based on the European Train Control System(ETCS),China has developed its own train control system,the China Train Control System(CTCS),and has vigorously conducted research on the technology.One critical component of the CTCS system is the point transponder system,which plays a vital role in transmitting key information(such as slope,speed limits,and elevation changes)between the ground responder and on-board BTM equipment.The maglev train adopts DC power supply.A constant magnetic field will be generated between the power supply rails in some sections.Due to the lack of relevant standards,the impact of the constant magnetic field electromagnetic environment on the responder equipment cannot be estimated.Therefore,it is of great practical significance to accurately predict the effect of the constant magnetic field on responder performance and to propose solutions to optimise responder performance to ensure the safe operation of the train control system and the overall safety of the train.This article addresses the above issues,and the research content and innovation points are as follows:(1)Determine the impact of the constant magnetic field on passive responders.By applying portable responder testing equipment,this study obtained the changes in the uplink signal characteristics of the responder,including center frequency,frequency offset,average data rate,amplitude jitter,MTIE,and the effective range of the responder under a constant magnetic field.Building on this,the principle of responder disturbance under a constant magnetic field is derived,and its accuracy is verified through a series of tests and analyses.(2)Conduct interference testing on passive responders in the laboratory.The impedance analyzer,digital oscilloscope,and spectrum analyzer were used to perform device-level,module-level,and system-level interference testing on the passive responder equipment.The inductor elements’ features,power module input/output waveforms,and the BTM decoding board operation were tested to identify vulnerable components and determine the interference source’s intrusion path.(3)Based on the interference test results,two optimization schemes for passive responders were proposed.The first one is based on the magnetic circuit splitting principle,and a constant magnetic field shielding shell was designed,which was verified for its reliability through simulation and experimentation,greatly reducing the degree of interference of the transformer element.The second one is to change the placement angle of the magnetic-sensitive components to reduce the overall disturbance level and increase the responder’s anti-interference threshold.Both schemes were verified for their reliability through electromagnetic simulation and experimentation. |
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