Maximum energy extraction from solar photovoltaic array under partial shaded conditions

Abstract

Considering the high initial capital cost of a Solar Photovoltaic (SPV) source and its low energy conversion efficiency, it is essential to operate the SPV source at Maximum Power Point (MPP) so that maximum power can be extracted. Techniques to extract maximum power from SPV Arrays (SPVA) where some of the cells are not receiving the full insolation (partial shaded condition) has been presented in this thesis. Effects of reconfiguration of the array and tracking of load have been analyzed for maximum power availability. This thesis aims at maximizing the energy obtained from SPVA under partial shaded conditions through a more accurate SPV model, better configuration of arrays and optimized Maximum Power Point Tracking using artificial intelligence methods. An improved model of SPV module suitable for analysis under partial shaded conditions is developed. Simulation study to investigate the harmful effects of series connected cells has been carried out using MATLAB. The same study has been extended to series connected and parallel connected SPV modules. From the analysis of various SPVA configurations with respect to environmental parameters by developing a more realistic model using MATLAB M-file, the following conclusions have been drawn. In order to obtain the maximum possible power under partial shaded conditions it is mandatory to connect a bypass diode in anti-parallel with a module or group of cells to avoid the stress on the shaded cells. Also it can be concluded that TCT is the best configuration for symmetrical array size and the proposed MB configuration for asymmetrical array sizes. Comparison studies have been made for PI and fuzzy controller. From the simulation results, it is observed that the feed forward control strategy with fuzzy controller reduces error and it is a promising one with reference to GMPP tracking. By implementing proper SPVA reconfiguration and effective GMPP tracking based on intelligent techniques, maximum energy can be extracted from SPVA under partial shaded conditions.