Conversor MPPT de estágio único conectado à rede elétrica baseado no conversor de capacitor flutuante

Abstract

Considering the current trend of growth of systems based on renewable energy sources, mainly photovoltaic distributed generation (DG’s), new topologies of DC-AC converters are being developed for conversion systems with a focus on multilevel converter structures, in order to increase efficiency at the lowest possible cost. This work describes a literature review on photovoltaic energy processing, including the operation of the solar system, MPPT methods, types of converters used and modulation strategies. After the review, a new grid-connected single-stage DC-AC inverter topology is presented, inspired by the flying capacitor multilevel converter cell. All components of the proposed converter were dimensioned and, for validation, a simulation structure was developed using the MPPT control through the incremental conductance algorithm acting only on the modulating signal angle, with unit modulation index. As a modulation strategy, PWM modulation with two phase shifted carriers (PS-PWM) was used. The system was simulated in the MATLAB®/Simulink environment for a 6.4 kW photovoltaic system at 25 ◦C and subjected to changes in irradiance to analyze the behavior and performance of the converter.