Implementation of a Smart Battery Charger Using LLC Resonant Converter

Abstract

This research was influenced by the need to eradicate voltage selection error in manual battery charging, as well as the necessity of charging more batteries within a short duration without compromising the cycle life of a battery. Minimizing human interference in battery charging as a means of making the process stress-free, safer, and faster also served as a motivation for this work. This paper presents a battery charger that takes accurate decisions by itself and eliminates poor charging parameters that can damage even brand-new batteries. The battery charging unit automatically senses the battery terminal voltage(s), supplies appropriate charging voltage/current, and terminates the charging process based on preset operational conditions of voltage, current, and temperature.Key components of the developed prototype include the 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 the 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 construction, 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 the objectives of the research.