Research And Develop The Online Monitoring System And Estimate The Capacity Of Emergency Power Battery

The Emergency Power supply System(EPS) and Uninterruptible Power supply System(UPS) have been paid more and more attention with the rapid development of power electronic technology. They shoulder important responsibility of stability and security in the enterprise, hospital and other related situations as an emergency power.The battery as the core of the emergency power supply part, its running state is normal or not directly affects the reliability and safety of the application of various electrical equipment. This paper design a method of capacity prediction and develop a set of battery monitoring system with a valve controlled sealed lead-acid accumulator without maintenance as the research object according to the relevant requirements of the national battery standard GB/T 19638.2-2005 and GB/T 19639.1-2005. The mainly study and completed tasks is elaborated with the following aspects in this paper:Firstly, the working principle of the battery, analyses the relationship between charge and discharge characteristics, the battery internal resistance characteristics and the performance parameters; to study the methods of battery parameter detection,analysis and comparison of the advantages and disadvantages of each method; study the relation between the battery capacity and other parameters, put forward a kind of on the gray theory the foundation, established the gray model to predict the volumetric method. To the terminal voltage and the internal resistance of the battery of the battery for two related factors, the establishment of GM(1, N) gray model to realize the prediction of capacity; according to the process of building the model close to the weighted parameters, put forward a kind of effective method to improve the parameters of model.Secondly, bring the AD conversion module with STC12C5A16S2 micro controller as the main control chip, the detection circuit of the battery voltage and temperature design; impedance detection circuit uses AC injection method design of battery based on the study on the method for measuring internal resistance, which in order to reduce the interference of environmental noise in order to improve the detection accuracy, the introduction of lock-in amplification technology, and withthe use of high precision instrumentation amplifier chip AD620 and AD630 chip using balance reconciliation; LCD touch monitor implementation at site of human-computer interaction.Thirdly, the interface of the monitoring software are programmed by using Microsoft interface library MFC framework and C++ programming language;communication between software and the terminal monitor realize through serial port by using the multi-threading technology; the detection parameter database is established by using SQL Server 2008, and realize the data curve drawing based on the Active X control. To avoid the possibility problems like crash of the software some tests has been done.Finally, the reliability properties of the monitoring system are verified by test.The experiment results show that the residual percentage of the proposed capacity prediction results is 3.9%, the degree of association is 71.8%, posterior error ratio is0.177; the minimum relative error reaches 0.3% in monitoring terminal voltage, 10%in monitoring internal resistance of battery and 3% in temperature measurement.