Studies of the PV Array Characteristics with Changing Array Surface Irradiance

Abstract

This paper presents a brief analysis of the photovoltaic (PV) modules that are currently commercially available. The most used calculation formulas and measurement procedures used for evaluating the power characteristics of photovoltaic PV modules are given. The possible causes of power losses of solar cells and modules are described, including losses caused by design features. The theoretical calculations and experimental results of measuring the characteristics of silicon PV arrays with changing surface irradiance are compared. The calculated and experimental dependences of the power output variation of the ISM-50 photovoltaic module with changing its tilt angle are presented. It is shown that there is a significant discrepancy between theoretical studies and experimental results. A hypothesis has been put forward about the dependence of a real decrease in power characteristics and refraction indices of PV array protective coatings. An adjustment factor is proposed taking into account the decrease in the solar radiation output on the silicon photocell surface when passing through the antireflective protective coatings of the PV module. The conclusions drawn from the results of this work indicate that the identified factors affecting the electricity generation by photovoltaic converters need to be considered.