Study On The Battery On-line Monitoring System

Along with the rapid development of telecom network and computer network, valve regulated lead acid (VRLA) batteries are used to provide uninterrupted power supply in a growing number of occasions for improving the reliability of powersupply system. Power interruption are not allowed especially for some important equipment. For example, communication system, power control system, accounting system etc. Thus, the working state of battery can be taken as the characteristic parameter to guarantee equipment operation. In fact, VRLA batteries may work in a long term no maintenance state in many cases. Many reasons such as dryout, fever, weeping, insufficient charge, overdischarge, resistance increases of individual battery may cause batteries failure which will seriously affect the normal operation of power supply system. So the regular detection and online monitoring of battery are very importance and must be treated with more attention.First the paper introduces the necessity and importance of the research on battrry online monitoring, then introduce the situation of battery detection and analysis the properties and function of the products all over the world. The battery online monitoring system and battery capacity testing are regarded as the research object, and a scheme based on Cirrus Logic's EP9315 processor and embedded linux operating system is proposed. The hardware structure and software design of the system are also introduced. The system can monitor battery inner resistance, voltage, charge-discharge current and temperature, and predict the battery capacity as well. Each battery was monitored by independent data collection module. Short-distance wireless communication technology based on CC1100 was applied to transfer data between master module and data collection modules, and this application can omits the complicated wiring. The master module communication with remote computer through the GPRS network which can ensure the battery operation data uploaded rapidly.There is a close relation between battery inner impedance and battery capacity. This System tests each battery inner impedance by AC discharge, and AC square wave was used in order to measure the battery inner resistance accurately. The paper gives a detailed analysis of test current and filtering algorithm was adopted to accurately calculate battery AC impedance. The state of charge is one of the most important performance of battery. Because VRLA battery is a complex electrochemical system, there are very complicated physical and chemical changes in battery during the charge-discharge process, it is difficult to test the residual capacity of battery online. This paper discusses the application of Fuzzy Neural Network optimized by Genetic Algorithm in battery capacity testing which has wide prospect.