A novel prediction algorithm for solar angles using solar radiation and Differential Evolution for dual-axis sun tracking purposes

• Published in: Solar energy 2011-11, Vol.85 (11), p.2757-2770
• Main Authors: Seme, Sebastijan, Štumberger, Gorazd
• Format: Article
• Language: English
• Subjects: Active sun tracking; Applied sciences; Differential Evolution; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Energy; Equipments, installations and applications; Exact sciences and technology; Mathematical models; Natural energy; Optimization; Photoelectric conversion; Photovoltaic; Photovoltaic cells; Photovoltaic conversion; Solar angle predictions; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Solar energy prediction; Solar radiation; Sun; Tracking systems; Trajectories; Ultraviolet radiation
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2011.08.031

► Two-axis sun tracking system for a photovoltaic system. ► The trajectories of the system are determined in an optimization procedure. ► The goal is maximization of an electric energy production in the PV system. ► The nonlinear and bounded optimization problem. ► Objective function is not available in the explicit form. This paper deals with a dual-axis sun tracking system for a photovoltaic system. Its trajectories are determined by an optimization procedure. The optimization goal is the maximization of the electrical energy production within a photovoltaic system, by considering the tracking system consumption. The procedure used for determining the tilt angle and azimuth angle trajectories is described as a nonlinear and bounded optimization problem. Since an explicit form of the objective function is unavailable, a stochastic search algorithm called Differential Evolution is applied as the optimization tool. In order to evaluate the objective function, models for calculating the available solar radiation and tracking system consumption are applied together with the efficiencies of solar cells, a DC/DC converter and inverter. A new algorithm is introduced for the time dependent prediction of available solar radiation. It is based on the length of a sunbeam’s path through the atmosphere and the statistical data of a pyranometer measured total and diffuse solar radiation at a given location on the Earth. The optimization bounds are given in the form of angular speed, lower and upper bounds for both angles and angle quantization. The results presented in this paper show, that the optimal trajectories can help to increase the electrical energy production within photovoltaic systems by sun tracking.