Design And Realization Of Lead-acid Battery Fast Charger

Lead-acid battery has many advantages such as large capacity, high performance-price ratio, large range of working temperature, safety, reliability and rich of raw materials, all of these characteristics make the lead-acid battery became one of the most widely used and the most mature batteries. As the increased using of Lead-acid battery, unreasonable charging methods lead to decreasing the capacity of the battery and shortening their service life, so people have to abandon them. This phenomenon generates serious resource wasting and pollution, so we hope to have a new charging method which is efficient, safe and reliable that can encourage people to deeply study the intelligent fast charging theory. The paper presents a intermittent variation-current positive and negative pulses fast charging method which is on the basis of the fuzzy control technology, gives the hardware circuit implementation of the charging system.The main content of this paper as follows:it introduces various charging methods of the lead-acid battery, and compares their advantages and disadvantages, through analyzing of the Mas charge current curve, then proposes the charging method of polarization intermittent variation-current; Based on Single-chip microcomputer PIC16F877A, designs the hardware circuit of the fast charger, it includes the main switch power supply circuit, charging and discharging circuit, voltage and current detection circuit, temperature detection circuit, input and output circuit, keyboard display circuit and auxiliary power supply circuit; the paper still designs two fuzzy controllers, the first controller is used to control the charge current and the second controls the pulse width, it discusses the membership function and fuzzy control rule of the fuzzy controller deeply; Also presents the process of the software and analyzes the various control module details, it includes main program, interruption program, the charging fuzzy control procedure and discharge fuzzy control subroutine.Finally, it takes on experiments on the hardware and software of the charging system of the lead-acid battery, the results of experiment prove the reasonability of the design of system and the feasibility and effectiveness of charging method proposed above.