Research And Design Of Battery Charging System

With the increasing scarcity of energy resources and intensification of environmental pollutions, the green industries, such as photovoltaic power generation and electric vehicles, have become the focus of attentions. Lead-acid battery, as a reusable chemical battery, has a very wide range of application in these areas, but its service life is always influenced by charging. Therefore, a battery charging system is designed and developed in this thesis, which is fast, safe and intelligent.Firstly, an overall scheme of the charging system is designed, according to the functional and technical requirements of the charging system. Double switch flyback converter topology is used in the power circuit, while digital control techniques are applied in the charging system based on MSP430F2274 microcontroller. Besides a multi-mode charging control strategy is adopted, which is comprised of active charging, large-current fast charging, over charging and float charging.Then, design and implementation of hardware and software are introduced in details. system hardware mainly includes flyback transformer, charging controller, driving circuit, sampling circuit, protection circuit and auxiliary power supply. The software mainly includes PWM generation, A/D sampling, digital PI regulator and LCD display. Digital control system is simulated in Saber environment, verifying the digital control of charging system and charging performance by establishing the digital control model of MSP430F2274.Finally, a set of battery charging system is developed and tested. Experimental results show that, output voltage and current of the charging system are constant. The charging system realizes the multi-mode charging control strategy and achieves the system functions and requirements.