Stand-alone Photovoltaic System using an UPS Inverter and a Microcontrolled Battery Charger based on a Boost Converter with a 3 State-Commutation Cell

This paper presents a stand-alone photovoltaic energy system aimed for small power consumer applications in isolated areas of the countryside of Brazil. In order to develop a cost-effective and simple product, a double power conversion UPS (uninterruptible power supply) was analyzed and modified. A whole new battery charger was implemented using a PIC microcontroller equipped with a MPP seeking algorithm, to maximize the energy extracted from the solar panels, and a supervisory unit to control the charge process of the batteries, in order to ensure that they are fully charged