Analysis and Optimizing the Performance of Photovoltaic Power Systems under Partial Shading Condition.

Document Type : Research Studies

Authors

1 Prof, Electrical Engineering Department, Faculty of Engineering Mansoura University, Egypt, She is the head of Electrical Engineering Department

2 Faculty of Engineering, Mansoura University, Department of Electrical Engineering.

Abstract

Growing shortage of fossil fuels and increasing emissions of CO2 make it a must to increase relying to the renewable energies for meeting the growing needs of consumers. In Egypt, the availability of solar energy put photovoltaic (PV) systems among the most important of these energies. The performance of Photovoltaic (PV) systems is deviated severely under partial shading condition (PSC).And this deviation is not determined in straight forward way, since it is not depending on the shaded area only. In this paper we have been present a simple methodology to evaluate accurately the characteristics (c/cs) of large and small scales of PV systems when one cell or group of cells in different sub-modules are partially shaded based on well-established algorithms. We enlarge this methodology to analysis then optimize the performance of PV arrays under PSC in different criteria for different series-parallel configurations of modules inside the array, with and without different numbers of bypass diodes ( ) and using the shadow length compensation algorithm which prevents the mutual shading between arrays through adjusting the tilt angle. A Matlab simulation is done to verify the theoretical analysis for Al-Arish at 17th January which is the average day in January. We found that the impact of increasing the number of Dby to optimize the performance of PV systems under PSC depends on the shading ratios. Also we found that the harmful impact of PSC on PV systems depend on the number of sub-modules under PSC, the length of strings and number of strings connected in parallel. This methodology should be applied for optimizing and sizing PV systems which are partially shaded.

Main Subjects