Development of a Simple Method for Optimizing Photovoltaic Array Arrangement

Abstract

Direct conversion of sunlight into electricity can be accomplished by using photovoltaic cells made of semiconductor material, which work by the photoelectric effect. Photovoltaic cells are usually connected in larger units called panels that are in turn wired together into arrays. Mismatches among the output characteristics of the photovoltaic panels within an array reduce the array output from the practical maximum. The array can be made most efficient by connecting the panels in series and parallel combinations chosen to minimize the effect of the mismatches. Elaborate computer programs have been used for large array analysis, a technique too costly for smaller applications such as residential dwellings. He present a practical method for optimizing the array configuration using easily measured panel parameters. Equations are derived voltage to predict based on a panel's maximum power current and its effective series resistance, open-circuit voltage, short-circuit current, and cell temperature. Relative insulation levels are also measured and used to normalize raw data to standard conditions. Measurements of the maximum power point using an I-V curve tracer are compared with values predicted by the simplified method. A simple procedure is then given for optimizing the placement of the panels in the array. The cost-effectiveness of array optimization is analyzed.