Power Enhancement under Partial Shading Condition Using a Two-Step Optimal PV Array Reconfiguration

Under partial shading conditions, photovoltaic (PV) arrays are subjected to different irradiance levels caused by nonuniform shading. As a result, a mismatch between the modules, a reduction in the power generated, and the hotspot phenomenon will be observed. One method to reduce mismatch losses is to reconfigure the total-cross-tied (TCT) array in dynamic and static forms, where improved performance can be achieved through more efficient shading distribution thanks to increased dimensions. However, the increase in dimensions leads to the complexity of wiring and installation in static reconfiguration and the large number of switches and sensors required in dynamic reconfiguration. To rectify these problems, a two-step method is proposed in this paper. In the first step, the modules inside the PV array are divided into subarrays with wiring in static reconfiguration, rather than being wired as large-scale PV arrays. In the second step, an algorithm is developed for dynamic reconfiguration. The introduced algorithm searches for all possible connections and finally identifies the most optimal solution. As an advantage, this algorithm employs only the short-circuit current values of the subarray rows, which reduces the number of switches and sensors required in comparison to dynamic reconfiguration. Under 8 different partial shading patterns, simulations are conducted and results confirm that the proposed method outperforms the TCT array and statically modified TCT array in terms of power and mismatch losses. Among these, the highest power improvement is obtained with regard to the TCT array and statically modified TCT array under the fourth and eighth shading patterns, respectively.

A Novel T-C-T Solar Photovoltaic Array Configurations using Rearrangement of PV Modules with Shade Dispersion Technique for Enhancing the Array Power

Total-Cross-Tied (TCT) solar array configuration has more output power under uniform irradiance condition (un-shade case) among all conventional solar photovoltaic (SPV) array configurations but reduced array power under non-uniform irradiance cases (shading cases). To improve the performance of TCT array configuration under shading cases by using rearrangement or repositioning of existing photovoltaic (PV) modules in TCT configuration to new optimal locations within a TCT array configuration with shade dispersion technique. In this rearranged method, repositioning the modules based on puzzle pattern without altering the electrical connections among modules in an SPV array. The shading on PV modules are dispersed by changing the position of PV modules to optimal locations within SPV array so the performance of conventional TCT configuration will be improved. In this paper proposed an optimal TCT configurations, it requires a minimum number of electrical connections or ties between array modules and it depends on the shaded modules location in SPV array and also the proposed method reduces the wiring losses, mismatch losses. For this analysis, MATLAB/Simulink software is used for modeling and simulation of 6x6 size different rearrangement based TCT and proposed optimal SPV array configurations under one un-shaded case and fourteen different shading cases.