Partial shading (PS) phenomena significantly degrade the power output from the photovoltaic (PV) array. Due to the PS effect, there is a mismatch in current between the PV modules of a series-connected PV string. As a result, in-shaded module power dissipates, resulting in increased module temperature and the creation of local hotspots. To avoid the hotspot effect, bypass diodes are connected anti-parallel to the PV modules. But the activation of bypass diodes creates multiple peaks in I-V and P-V characteristics. The effect of PS can be reduced by using a suitable array configuration and the performance of the PV array gets improved. Among all the existing PV array configurations, the total cross-tied (TCT) configuration performs better under partial shading conditions (PSCs). But the disadvantage of TCT is that it has an enormous number of tie connections, creating complexity in an array configuration and, therefore, more cable losses. The main objective of this paper is to propose a novel array configuration named benzene (BZ) configuration, which eliminates the demerits of the TCT array configuration. Benzene configuration has improved performance with fewer tie connections compared to conventional tie-connected configurations such as TCT, bridge link (BL), and honeycomb (HC). The performance of the tie-connected array configurations is analyzed under different PSCs by considering the various performance parameters such as global maximum power (GMP), the voltage at maximum power (Vmp), current at maximum power (Imp), mismatch loss (ML), shading loss (SL), fill factor (FF) and performance ratio. It is observed that the proposed benzene array configuration gives better output performance, even having lower mismatch losses with a reduced amount of tie connections. Further, the effect of the bypass diode on a partially shaded PV string is investigated through MATLAB Simulation and experimental analysis.

This paper compares different methods for extraction of photovoltaic (PV) module parameters. Nonlinear least-square method based on trust-region algorithm is proposed here to extract five unknown parameters such as series resistance (R _s ), shunt resistance (R _p ), diode ideality factor (a), dark saturation current (I ₀ ) and photo-generated current (I _pv ) under standard test conditions (STC) of PV module. Comparative analysis has been drawn between the proposed method and two other popular methods such as Villalva's iterative method and modified Newton-Raphson method. The principle of trust-region algorithm is briefly reviewed. Two parameters R _s and R _p are only extracted by Villalva's iterative method whereas all five unknown parameters can be extracted by the proposed method and by modified Newton-Raphson method. The accuracy of estimated parameters depends on tolerance band and initial conditions. The time of computation for parameter extraction of different methods has been compared.

Partial shading (PS) is a major challenge faced by photovoltaic (PV) arrays invoking mismatch loss (ML). In this paper, the effect of PS on PV array performance is analyzed through experimental results and MATLAB simulation. The effect of PS on PV characteristics is investigated in two conditions. In condition one, modules are not coupled with bypass diodes, and in condition two modules are equipped with bypass diodes. New mathematical equations have been derived to calculate ML for condition one, and for condition two; locations of power peaks are identified in the power-voltage (P-V) curve. For both the conditions, theoretical results are verified through experimental results. From the obtained results it is observed that the error in loss calculation for condition one is less than 2% and for condition two, power peaks are being identified analytically with less than 3% error. To reduce the effect of PS on PV array, different configurations of the PV array were considered in the earlier literature. Among all, Total Cross Tied (TCT) PV array configuration is popularly used for its improved performance. To curtail the cost of TCT, two-hybrid array configurations such as TCT with bridge link (TCT+BL) and TCT with honey-comb (TCT+HC) are proposed here. Performances of different array configurations are analyzed considering various parameters such as global maximum power point (GMPP), currents and voltages at GMPP, the number of local peaks, shading losses, and mismatch losses. It is observed that proposed array configurations outshine in performance by reducing the amount of ML and the number of local peaks in the P-V graph, mainly for the stochastic shading patterns.