Research And Design Of Monitoring System Of Supply Unit Of Optical Fiber Motion Attitude Equipment Based On ARM

With the rapid development of battery technology and the widely usage of Optical Fiber Motion Attitude Equipment on modern warships,lithium battery is beginning using as the backup power of Optical Fiber Motion Attitude Equipment replacing the traditional lead-acid battery,relying on its lots of advantages as small volume,light weight,long life,high energy quality ratio,low discharging ratio,no pollution.To insure the power equipment operating safely and stably,it is necessary to monitoring and analyzing the related parameter,predict the remaining discharging time and electric quantity,and issue the alarm when any exception happen during the procedure of discharging in the real time.Based on this background,we designed hardware platform of lithium battery monitoring system,implemented the human-machine interface with the software platform of embedded Linux,forecast the remaining discharging time and electric quantity using state-of-charge estimating algorithm.To improve the stability,simplify the hardware design,support the human-machine interface,we chose the framework of ARM and the type of S3C2440 chip from Samsung Corporation to be its master chip.It contains powerful support of power,clock system and memory.Its inner 8-channel 10-bit analog to digital converter could implement the detection of battery parameter and the interface of touchscreen,its abundant GPIO could implement the system expansion.Inner UART and USB controller could implement Bluetooth and high-speed downloading.Two digital temperature sensors and bidirectional DC sensor with changeable range could implement the detection of battery temperature and environment temperature and discharging current.And,mini SSR and electrolytic capacitor implement the voltage detection and insulation blocking.Embedded Linux provided thorough software platform.Boot loading program implements the downloading and the setting of boot parameters.The Linux kernel of version 2.6.31 provided system management and process scheduling mechanism more thoroughly.The application based on QT4 provided attractive and friendly human-machine interface.In addition,the booting speed and expansion was improved by the manner of compiling the driver as modules.For Optical Fiber Motion Attitude Equipment operating in complicated environment,precise and rapid SOC estimating algorithm could improve the real-time of system,and it was significant for the system operation safely and stably.Due to the method of traditional ampere-hour integration merely detected the battery current,it could not reflect the effect of environmental factors to battery operation situation,and could not estimate the initial value.What is important is the integration in the algorithm accumulated the error and reduced the estimation precision.Therefore,the algorithm was improved by monitoring and analyzing the parameter as voltage,battery temperature,environment temperature,on the base of current detection.The ampere-hour integration was compensated and corrected by system modeling and experimental analysis,and was completed with parameters of cycle life and discharging rate to improve the estimation precision.The algorithm before and after modified was simulated and tested by Matlab.The result showed that the algorithm after improved was suitable for more complicated situation and its precision had been notable improved.