Análise comparativa de conversores cc-cc elevadores de tensão aplicados a sistemas fotovoltaicos de duplo estágio de conversão de energia conectados à rede elétrica monofásica

Abstract

This work presents a study of photovoltaic systems connected to single-phase power grid, which involves three topologies of DC-DC step-up converters, being the Classic Boost converter, the Quadratic Boost converter and the Cascaded Boost converter. The DC-DC converters are used to voltage step-up of two types of photovoltaic arrangements, where the first is composed of two parallel-connected photovoltaic panels, while the second is composed of two series-connected photovoltaic panels. The photovoltaic systems are connected to the power grid by means of a currentcontrolled Full Bridge Voltage Source Inverter (VSI) and an inductive filter. The maximum power point tracking of the photovoltaic array is done using the Incremental Conductance method, while for the synchronism with the grid voltage the Phase-Locked Loop (PLL) algorithm is used. In the modeling and simulations the resistive losses in the inductors, capacitors and switches of the DC-DC converters are considered. Thus, a more precise comparative analysis involving the efficiency of the studied structures was possible, which also allows the optimization of a double-stage system in relation to the reduction of energy losses. Finally, photovoltaic systems were evaluated considering their operation through variations in solar irradiation, temperature and when subjected to partial shading.