Shadow Modelling Algorithm for Photovoltaic Systems Analysis and Simulation

Abstract

In this paper, an algorithm capable of modelling shadows from nearby obstructions onto photovoltaic arrays is proposed. The algorithm developed is based on the calculation of the solar position in the sky for any given instant in order to obtain the shadow projection for any object point. The convexity properties of objects and their shadows are used to allow a precise three-dimensional solution with reduced computational power without the need to consider a vast grid of points. The idea is extended to provide the shading patterns for a desired range of time and to calculate the eciency rate of the irradiation power incident on the array in comparison to the non-shadowed case. The algorithm has interesting applications, such as optimizing array positioning and orientation, evaluating the impact of new obstructions on pre-existing array installations, allowing precise and practical data for control strategies and MPPT techniques for partially shaded systems, calculating more realistically constrained payback scenarios and nding the optimal PV array interconnection. The results obtained are illustrated by a numerical example, in which the eects of a nearby building in the irradiation received by a photovoltaic array throughout the year is analyzed.