This research was influenced by the need to eradicate voltage selection error in manual battery-charging, as well as the necessity for getting more batteries charged within a short duration without compromising the cycle life of a battery. Minimizing human interference in charging of batteries as a means of making the process stress-free, safer and faster is also a motivation for this work. This paper presents a battery charger which takes accurate decisions by itself and eliminates poor charging parameters which can damage even brand new batteries. The battery charging unit automatically senses the battery terminal voltage(s), supplies appropriate charging voltage/current, and terminates charging process based on preset operational conditions of voltage, current and temperature. Key components of the developed prototype include PIC16F877A microcontroller chip, LLC resonant converter, and an LCD based display unit. The chip runs dedicated codes that control all tasks involved in the operation of the charger. Pulse-width modulation (PWM) technique was employed to control switching duty cycle which consequently varies the output of the converter and enables battery-charging from 6-volt to 48-volt. Before embarking on the actual constructions, simulations were done to evaluate the performance of the system. The model was subjected to tests under various load conditions and the results agreed with objectives of the research.
Implementation of a Smart Battery Charger Using LLC Resonant Converter