Forecast Research And Engineering Applications Of Residual Capacity Of Lead-acid Storage Batteries

Solar photovoltaic power generation system has the advantages of pollution free, unsusceptibility to regional influences, high operational reliability and low cost. Solar street lamp systems are a typical standalone PV(photovoltaic) system in which lead-acid storage batteries are the main energy storage components．In order to improve efficiency of lead-acid storage batteries and to effectively extend their service time, it is required to prevent the batteries from being overcharged and over-discharged. Therefore, the residual capacity of lead-acid storage batteries should be accurately estimated. Due to the complex electrochemical characteristics of lead-acid storage batteries，it is difficult to measure the residual capacity directly. This thesis presents a method to estimate the residual capacity of lead-acid storage batteries, and discusses some applications in a real solar street lamp system.Firstly, some basic characteristics of lead-acid storage batteries are introduced, and several common estimation techniques for the residual capacity are analyzed. Then, an artificial intelligence forecasting method, the neural network method, is studied to estimate the residual capacity. In this method, The LM(Levenberg-Marquardt) algorithm is applied to train the network, and a three-layer BP neural network model, which can be used to estimate the residual capacity, is obtained. The performance of this model is verified with MATLAB．Simulation results indicate that the neural network used for residual capacity estimation is feasible.Secondly, structures and functions of a real solar street lamp system based on an MSP430F235microcontroller are introduced. The hardware and software design for discharge control are discussed in detail．Finally, according to the estimated residual capacity of lead-acid storage batteries based on the neural network method, a discharge control method is designed for the solar street lamp system. Applied to the solar street lamp system for discharge control, the method proves to be effective and can meet the practical requirements．...