Contribution To The Study Of A Single-Phase And Single Stage Photovoltaic System

This paper deals with grid-connected single-phase photovoltaic (PV) systems and presents the design steps of a fully functional prototype, based on the full-bridge voltage-source inverter, being controlled by means of a low-cost integrated circuit (IC). Two-stage and single-stage arrangements are described with the aid of a didactic approach. It is shown that the average current control technique enables tracking the maximum power point of PV panels and allows attaining a low distortion, high power factor output current. The main contribution of this work is to demonstrate that those main functions, maximum power point tracking and low-distortion current synthesizing, can be accomplished by means of the IC UC3854. Since this integrated circuit is commonly employed in high power factor ac-to-dc pre-regulators it is required to provide an adaptation, which is described in the paper. Digital simulation as well as experimental results of a 720 W prototype are presented and validate the intended proposition.