PV array power output maximization under partial shading using new shifted PV array arrangements

Abstract

Partial shading can dramatically reduce the power output of a PV array as well as complicate operation by causing multiple peaks to appear in the power-voltage (P-V) characteristic curve. The extent of these problems depends not only on the shading area but also and much more significantly on the shading pattern. In this paper three new physical PV array arrangements are proposed to mitigate partial shading effects. The arrangements are based on maximizing the distance between adjacent PV modules within a PV array by appropriately arranging modules in different rows and columns without changing the electrical connections. A systematic analysis is performed to assess the proposed PV array arrangements under different shading patterns and scenarios, and to compare performance with existing configurations. The new arrangements are shown to effectively (i) redistribute shading patterns over the entire PV array, (ii) minimize protection diodes power dissipation, (iii) eliminate multiple peaks, and (iv) maximize power output. The analysis considers shading scenarios related to cloud shape, size, transmissivity and passage over an array. The new configurations simplify operation and improve performance significantly compared to the reference Series-Parallel (SP) and Total Cross Tied (TCT) configurations: the characteristic P-V curves exhibit a single peak allowing tracking of the maximum power point with a simple controller removing the need for complex controller algorithms and costly hardware, and the power output gains range from 19 to 140% compared to SP, and 13 to 68% compared to TCT.