| When the external power supply malfunctions in railway signal and communicationsystem, uninterruptible power supply (UPS) is mainly used in computers, power supply panel,computer interlocking system and the dispatching management information system to ensurestandby power supply. However, because batteries in UPS are operated under conditions offloating charge for a long period of time and batteries are lacked of reasonable maintenance,the decrease of storage capacity and reduction of battery lifetime can be caused, and thesecurity of railway transportation is affected. Based on those mentioned above, the onlinemaintenance system for multichannel UPS is designed and one sample machine is finished soas to ensure the stable operation of UPS used in railway signal and communication systemeffectively.Firstly, the thesis presents the functions, structures and operating principle of the onlinemaintenance system for multichannel UPS. Discharge characteristics and electricityprediction methods of UPS battery are studied. According to UPS battery experimental data,the reasonable depth values of UPS discharge maintenance are found. An AC-injectionmethod with a phase-locked amplifier as core part is proposed, and is used to measureresidual capacity of storage batteries. Secondly, according to the requirements for themaintenance system functions, hardware and software for the maintenance system aredesigned, including the circuit of current and voltage acquisition along with temperatureacquisition, the clock circuit, LCD circuit, communication circuit and driving circuit for fastswitching thyristor. LabVIEW is used to develop control and management software for uppercomputer of the online maintenance system. With the design of double redundancy controland standby power supply for circuit boards, the reliability of the maintenance system isimproved. Finally, the debugging result of the sample machine is expounded in detail underconsideration of debugging process.The testing result of the sample machine shows that the maintenance system realizes allthe predetermined functions. Without any influence to normal operation of UPS, the batteriesunder long-time floating charge state are maintained by online discharge maintenance, whichreplaces the existing manual maintenance and reduces energy consumption. The onlinemaintenance system for UPS can detect the faulty batteries so timely that the purpose ofimproving UPS reliability and battery life is achieved and train operation accidents areavoided. Practical application of the online maintenance system has great social and economicbenefits. |
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