| As one of the most common second generation batteries, storage battery possesses wide spectrum of application due to its stable voltage output, high discharging rate at low temperature and low cost. In decades, with the development of communication and computational techniques, high performance storage batteries are demanded. Compared to convention lead-acid battery, VRLA storage battery also benefits from low pollution and maintenance cost. It has been applied in many areas such as, electric bicycles and cars, communication base stations, illumination and toys. Each storage battery has its characteristic reaction which in turn decides the recharging cycles. In order to improve the performance of VRLA storage battery, we not only need to consider the optimization of design, the charging method and its controlling is critical as well. Therefore it is important to investigate the charging method and monitor the charging procedure.In this thesis the basic theory about charging of VRLA storage battery is first introduced. After analyzing several charging methods, we propose a new generation smart charging method on the basis of fuzzy controlling. Starting from the basic theory and practical consideration, we carried on the selection of variable, establishment of fuzzy rule, fuzzification/anti-fuzzification and etc. These are all necessary to design a well-suited fuzzy controller. We also fabricate a new charging system which consists of STC90C58RD+ Single Chip Microcomputer (SCM). The whole system is built up main voltage source circuit and controlling circuit, which is comprised of microcontroller unit and transmitter detecting circuit. Moreover, there are triggering circuit and acquisition circuit for voltage, current and temperature mounted on the controlling circuit. We adopted the module development for the on-top software to meet the hardware system requirement. The entire software includes modules for fuzzy controller, constant current controller, charging termination controller and etc.Computer simulation of VRLA storage battery was conducted on the SIMULINK/MATLAB platform. Three different sets of parameter were applied to study the smart fuzzy charging system through conventional PID controlling and fuzzy controlling. In conclusion, the fuzzy controlling is excelled in ultra-fast response and small residual error. In addition, it is more stable and easy to deploy in the multivariable system. In non-linear and complication system, fuzzy controlling is even attractive. |
