Optimization Design Of Video Monitoring And Storage System For Metro Train

In the metro vehicle environment,the frequent power down and the temperature rising are the two key factors threatening the reliability of video monitoring and storage system.On the premise of realizing the basic functions of monitoring storage system,this paper mainly adopts two key technologies to solve these two problems:backup power based on super-capacitor,Power balance control strategy based on hard disk’s dynamic scheduling.The main research methods and my test results are reported as followed:After taking super-capacitor bank and boost DC/DC circuit as the structure of backup power,I establish its mathematical model and deduce the constraint equation among the main paraneters,so as to guide devices selection;by evaluating the video data flow demand and the date throughput capability of hard disk,s interface,I design appropriate power balance strategy to dynamically control hard disk’s access or exit.Using power balance method can reduce the power consumption of the system from 52 W to 25 W,while the capacitance,operating voltage and ESR of the super-capacitor bank are 12 F,10.04 V and 0.24Ω,respectively,the backup power can support about 10 seconds in meeting the need of CPU’s handling the power-off logic;and also,the temperature of the power module is reduced from 68.3℃ to 47.8℃;the surface temperature of the mechanical hard disk is reduced from 58.3℃to 46.6℃;and the temperature of the equipment chassis is reduced from 47.9℃ to 38.6℃.By comprehensively studying the fault location and characteristics of the video monitoring and storage system,this paper using the backup power and the power balance method can reasonably deal with the problems of frequent power off and the temperature’s over rise of the system,and so far the reliability of the system is strongly improved.