Research And Design On Intelligent Charger For 12V Valve-regulated Lead-acid Battery

The valve-regulated lead-acid battery becomes more and more widely application because of its excellent performance. The conventional charger is usually charging battery with little current. It takes more than 10 hours to charge a valve-regulated lead-acid battery by this charger. Because the conventional charger is often short of effectively control mode, it easily leads to charging over or charging shortfall. It will shorten life of the valve-regulated lead-acid battery, even than it will destroy the battery. In this paper we research and design a kind of intelligent charger for 12V valve-regulated lead-acid battery. The charger is based on switching power supply technology and microprocessor technology. The main content follows.1) The paper introduces the theory of the valve-regulated lead-acid battery and the theory of DC-DC converter circuit. It summarizes the existing charging mode of the valve-regulated lead-acid battery to this day.2) It simply introduces the Ampere Loop Theorem and Faraday's law of electromagnetic induction. And it detailed recounts the design of magnetism component in the charger such as transformer, filter inductance and EMI filter.3) The charger is controlled by two layers mode. The low layer is analog circuit. And the high layer is microprocessor. It avoids simplex and hidebound circuit control mode. And it easily realizes kinds of charging curves and arithmetic by software.4) The low layer analog circuit is PI controller. This controller can eliminate the static error and make the system stabilization in light load condition.5) The high layer is microprocessor. It easily realizes good charging curves and prolongs the life of the battery. The charger is convenient because of the microprocessor. In the same time the microprocessor can protect the charger form error operation damage. The protection includes output short circuit, the battery pole in reverse, the battery voltage too low and so on.