Improved Reconfiguration Optimization for Maximum Power Extraction in Total-Cross-Tied PV Arrays under Nonuniform Irradiance

One of the main obstacles to solar power production is the problem of partial shading and irradiance variation. The degree to which these factors can diminish the performance of a photovoltaic (PV) system depends on the specific shading pattern, PV array topology, and the physical location of the shaded PV modules within the array. The cause of which could be due to changing weather conditions, or particulate obstructions such as snow, ice, ash, or dust. An array that is capable of rapidly and purposefully rearranging its electrical interconnections is empowered to adapt to variable irradiation patterns, to failures of constituent solar modules, or even self-regulating power production in response to changing energy demands. In this paper, a block rearrangement technique, commonly used in the assembly line crew scheduling problems, is applied to equalize the irradiance summations of each row in a Total-Cross-Tied (TCT) array. The Block Rearrangement with Variance Equalization algorithm is based on the theory that for row sums to have minimum variance, the elements in each column need to be oppositely ordered to the row sums of the remaining columns. The performance of the proposed technique is verified under three shading scenarios. The results show that the applied technique can significantly reduce the mismatch power losses in partially shaded PV systems.