Análise da influência de células sombreadas nos parâmetros elétricos do módulo fotovoltaico quando estão operando em sol real

Abstract

Accurate characterization and prediction of voltage and current of photovoltaic cells under different operating conditions is essential to evaluate the reliability, efficiency and safety of photovoltaic modules. In these terms, the study of the behavior of the characteristic curve of photovoltaic modules is important because these systems generally operate in adverse environments, with different operating conditions and are therefore prone to failure. Several studies have been devoted to developing methods for analyzing the I-V curve considering the influence of different operating scenarios, such as temperature, shading, reverse conduction, variation of the solar spectrum, among others, in order to consolidate studies capable of contributing to the predictions of failures in photovoltaic systems. That said, this work analyzed the influence of different operating conditions of photovoltaic modules when cells are operating with different types of shading. The study unfolded in the existing qualitative analysis between the electrical parameters and the behavior of the IV curve. To this end, experiments were carried out with solar cells in 2 modules under real sun conditions. The IV curves were parameterized as established by the International Electrotechnical Commission (IEC, 60891). It was verified that physical anomalies in the cells have a greater influence on the electrical parameters than surface wear of solar cells. The experimental results reinforce that the irradiance photon flux is absorbed in its wavelength range even in cells that have more worn surfaces. In addition, this work also found that the transmission models of electrical parameters for cells that operate with shading, available in the literature, did not have a good physical fit in the field measurements performed, becoming a purely mathematical parameter. In light of these results, it is concluded that it is essential to carry out experiments under real operating conditions for the analysis of the operation of photovoltaic cells with shading.