Investigation of Operational Problems in Photovoltaic Systems

Abstract

Photovoltaic (PV) systems are gaining more attention worldwide. These systems are relatively expensive, and thus, they must be operated efficiently in order to obtain the maximum possible output. However, to achieve this task, the performance of these systems under different operating conditions should be thoroughly investigated. A thorough review of modeling PV modules from a commercial datasheet is presented. Detailed mathematical equations are presented from a cell to module to array. Hence, a developed model in Matlab/Simulink environment is presented. The model is then validated by comparing the I-V characteristics from datasheet to the simulated model results. In this research, three array configurations are considered in simulation analyses, these are: series-parallel (SP), bridge-linked (BL), and total-cross-tied (TCT). Abstract IV One of the most dominant factors that affect the generation of electricity from PV systems is the shading of PV arrays. Therefore, this thesis aims to investigate the problem of partial shading on different array configurations in order to identify the configuration that is comparatively less susceptible to shading problems. Moreover, the thesis attempts to provide guidelines that can help in predicting the expected number of peaks in the power-voltage curves for different array configurations under partial shading conditions. This can be of great benefit for the purpose of tracking the maximum power point under partial shading conditions. This thesis also investigates the impact of dust on PV arrays which is very important especially in desert regions like Egypt. This factor is examined to investigate the deterioration of PV modules performance by different amounts of sand dust particles. The results show an obvious reduction in MPP especially in the large amounts of sands on PV modules. For inclined planes, the results show similar effects to the partial shading conditions. The results obtained are shown in figures and tables. These results are discussed and explained in details. Keywords— Array configurations, partial shading, sand dust, modeling, photovoltaic array modelling