Técnicas de modulação por largura de pulso para conversor isolado em ponte completa com dois estágios aplicado a sistemas fotovoltaico

Abstract

This dissertation presents the study of a system of photovoltaic generation using micro-inverters. The main objective of this work is to analyze, design and develop a two- stage inverter, consisting of a isolated full-bridge DC-DC converter and a PWM full-bridge inverter, to inject energy into the grid from a single photovoltaic panel 260 W. The mathe- matical modeling of photovoltaic modules has been developed for both a serial and parallel connection. In addition, operation stages of the isolated full-bridge DC-DC converter and conventional PWM modulation techniques for the inverter are examined. The design crite- ria of an LCL output filter are discussed considering the effects of the resonance. Hereafter, two control strategies are introduced to inject current into the grid and to regulate the intermediate dc-link voltage. To verify the generation system operation, simulations using PSIM software were performed for open- and closed-loop at different irradiation conditions. Finally, theoretical analyzes and simulations were validated using a prototype, with which the efficiency and current total harmonic distortion measurements were obtained.