Battery Charging System for Solar Power Plant Using Buck-Boost Converter to Mitigate the Change of Light Intensity in Airport Area

Abstract

An area in the tropics has considerable potential for solar energy sources and can be used to provide electrical energy supply at airports, especially in inland areas, where Indonesia has about 237 airports. To utilize this solar energy, batteries and charge controllers are required as storage media. When using solar cells to exploit solar energy, the most commonly used charge controller today is the traditional voltage regulator. This regulator limits charging when the output voltage of the solar cell (regulator input voltage) is higher than the charging voltage of the battery. As a result, battery charging stops when the solar cells are obstructed by clouds or in the morning and evening when the sunlight intensity is low. This causes the battery charging system to work less efficiently during the rainy season. In this study, a battery charging system equipped with a buck-boost converter is built. The system uses feedback from solar cell output and battery input current and voltage sensors to control battery charging. A microcontroller acts as the control center of this battery charging system. The system maintains its output voltage according to the recommended battery charging voltage. As a result, the battery charging system operates continuously and stably, regardless of whether the output voltage of the solar cell is lower or higher than the voltage required to charge the battery. During periods of high sunlight intensity, i.e. between 10:00 am and 2:00 pm, the battery charging system test showed an efficiency rate of 78%. Overall, the average charging voltage was about 13.6 Volts with an average charging current of about 1 A. Under these conditions, the 12 Volt battery took about 5 hours to fully charge.