Photovoltaic Array Configurations Research Articles

Performance investigation of PV array under partial shading conditions with static array configuration and MPPT

ABSTRACT The performance assessment of a photovoltaic (PV) system in the partial shading conditions becomes essential to analyze the PV system for real-life applications. Under the present study, the performance of photovoltaic system under different partial shading conditions are investigated. The performance of different static array configurations of photovoltaic systems has been analyzed. A TCT (Total Cross Tied) configured static PV array has been found to enhance the output power to 1.14 kW with a bypass diode. Hence, the TCT configured static PV array configuration is connected with the MPPT controller. Multiple peaks in the characteristics curve under partial shading makes a challenging task for the control algorithm to find the global maximum power point (GMPP). Therefore, the MPPT strategy involves social learning differential evolution (SLDE), which considerably improves the tracking capability by the implementation of an inspection strategy. Change in different shading scenarios and load variations are considered to evaluate the performances of the proposed MPPT algorithm. The response of the investigated shading scenarios is validated in the MATLAB/Simulink environment as well as through physical experimentation. Based on the experimental results, it is found that the convergence time for tracking the GMPP is within 1.5 s and efficiency is more than 99%, which is reduced due to the use of considered MPPT strategy with an inspection strategy. There are no oscillations observed as the GMPP is achieved. Based on the obtained results, it is also observed that the considered methodology is also sensitive to load and shading scenario change.

Maximum Power Generation from Novel Triangular-Shaped PV Array Configurations under Partial Shading Conditions

Making photovoltaic (PV) systems more energy efficient is a huge challenge toward their widespread adoption. Partial shading is one of the major contributors of power reduction in PV systems. The interconnection scheme of the modules, the pattern of partial shading, and the module setup area determine the extent of power reduction. Conventional literatures contain arrays set up in rectangular and square shapes following various topologies to neutralize the adverse effects of partial shadings. Therefore, new areas of research may include connection of solar modules in new shapes to form unevenly sized PV arrays. This paper includes PV modules configured in six types of novel triangular connections and compares their performances under shading conditions. These interconnection schemes are (1) triangular series-series (TSS), (2) triangular series-parallel (TSP), (3) triangular parallel-parallel (TPP), (4) triangular honeycomb (THC), (5) triangular bridge link (TBL), and (6) triangular total-cross-tied (TTCT). Each of the six configurations are compared to one another, taking into account their different performance parameters such as maximum power, fill factor, and power loss. The TSS configuration method is found to have a better performance edge over TSP, TBL, THC, and TTCT configurations for all the considered parameters.

A Simple Method for Detecting Partial Shading in PV Systems

Partial shading conditions (PSCs) can significantly reduce the output energy produced by photovoltaic (PV) systems. Moreover, when such conditions occur, conventional and advanced maximum power point tracking (MPPT) systems fail to operate the PV system at its peak because the bypassing diodes may cause the PV system to become trapped at a low power point when they are in conduction mode. The PV system can be operated at the global maximum power point (MPP) with the help of global peak searching tools. However, the frequent use of these tools will reduce the output of PV systems since they force the PV system to operate outside its power region while scanning the I-V curve in order to determine the global MPP. Thus, the global peak searching tools should be deployed only when a PSC occurs. In this paper, a simple and accurate method is proposed for detecting PSCs by means of monitoring the sign of voltage changes (positive or negative). The method predicts a PSC if the sign of successive voltage changes is the same for a certain number of successive changes. The proposed method was tested on two types of PV array configurations (series and series–parallel) with several shading patterns emulated on-site. The proposed method correctly and timely identified all emulated shading patterns. It can be used to trigger the global MPP searching techniques for improving the PV system’s output under PSCs; furthermore, it can be used to notify the PV system’s operator of the occurrence of PSCs.

A novel population based maximum point tracking algorithm to overcome partial shading issues in solar photovoltaic technology

Maximum power point (MPP) tracking (MPPT) is a crucial aspect of photovoltaic (PV) technology for operating in an optimum location throughout the day. The bypass diodes are connected across series connected PV modules to avoid the hotspot phenomenon resulting in multiple peaks in the power-voltage (P-V) curve during partial shading conditions. Under this situation, tracking of global MPP (GMPP) for PV system by conventional approach is incompetent. Thus, a global MPPT controller is designed based on a novel population based algorithm, student psychology based optimization (SPBO), to enhance the overall performance of the 4S and the 3S configurations of the PV array. The effectiveness and the feasibility of SPBO algorithm for catching the GMPP are verified under several shadow arrangements. For proving effectiveness, the simulation results of SPBO are compared with human behaviour based optimization, improved chaotic particle swarm optimization (PSO), PSO, fuzzy logic control and teaching–learning based optimization. The proposed SPBO algorithm is able to successfully catch the GMPP under different weather scenarios and exhibits superior performance in terms of iteration, tracking time and efficiency. However, the temperature variation marginally affects the tracking efficiency of the SPBO method. This analysis is performed on the 4S configuration of the PV array. For better justification of the concept of stability, statistical analysis is also conducted on the 3S configuration of PV array separately.

Analytical approach to locate multiple power peaks of photovoltaic array under partial shading condition and hybrid array configuration schemes to reduce mismatch losses

ABSTRACT 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.

Hyper SuDoKu-Based Solar Photovoltaic Array Reconfiguration for Maximum Power Enhancement Under Partial Shading Conditions

Abstract This article focuses on the rearrangement of the structure of the photovoltaic (PV) array under different shading conditions. It aims to analyze the mismatch power losses (MPLs) due to irregular illumination over PV array (PVA). The impact of partial irradiance not only affects the electrical power but also causes multiple peaks in the P-V and I-V curves. The formulation of the best PVA configuration (PVAC) to achieve maximum output even under partial shading conditions is the deciding factor for the topologies considered. To aid the maximum power extraction, a new SuDoKu PVAC is designed like hyper SuDoKu (HS). This new structure is compared with the already existing PVACs such as bridge-link, honey-comb, series-parallel, total cross-tied, and SuDoKu in the effect of considerable cases of shadowing. matlab/simulink is used for the designing, and computer-based modeling of all these PVACs is considered in this study. The evaluation of these arrangements has been done by keeping several performance factors as the deciding pivot points. These factors include MPL, efficiency, global maximum power point (GMPP), and fill factor (FF). The results obtained through this document suggest that the HS arrangement proposed here gives the best outcome for each shading condition. The proposed HS structural arrangement of PVA deals with significantly superior GMPP, FF, and efficiency while maintaining minimum MPL in comparison to other arrangements.

Conventional and advanced PV array configurations to extract maximum power under partial shading conditions: A review

Occurrence of partial shading and its high impact on the performance of photovoltaic (PV) system have received considerable attention during the last few years. It has forced the researchers to explore more novel PV array configurations to sustain under partial shading conditions (PSCs). To diminish the effects of PSCs, this paper presents an overview of the state-of-the-art developments of various PV array configuration models for PV systems. Different modelling approaches are analyzed while emphasizing their benefits and inadequacies. Different models available in the recent state-of-the-art literatures are studied and categorized according to vital configurations and features. Mainly, various PV array configurations such as advanced, futuristic configurations are also compared with the existing configurations. In this paper, recent research developments (that deserve further examination) are acknowledged and deliberated for the future researchers working in this domain.

Enhance the Output Power of a Shaded Solar Photovoltaic Arrays with Shade Dispersion based TCT Configuration

Partial shading has a negative impact on the performance parameters of a Solar Photovoltaic (PV) array, because it shades certain panels while leaving others un-shaded. This article focuses on modeling, comparing and performance assessment of 6×6, 6×5 and 5×6 size shadowed solar PV arrays under different partial shading cases in the MATLAB/ Simulink software. For this purpose, the simulation of series-parallel (SP), Total-Cross-Tied (TCT) and proposed shade dispersion based TCT (SD-TCT) type of array configurations was carried out under few shading cases. The proposed SD-TCT was designed using the shades dispersion technique, which is based on a number logic approach. In this technique, in order to effectively remove the row-current mismatches in the TCT PV array configuration, the shaded and un-shaded modules in an array were re-arranged, so that the shading on modules expands across the whole array. The physical placement of the TCT array modules has been reordered in accordance with the proposed number logic pattern exclusive of altering the electrical links among the panels. The simulation results showed that the performance of the SD-TCT type was superior to that of conventional array configurations.

DC Motor Load performance in DC system with reconfiguration of PV Array

Objectives: To examine if the changing of the series-parallel configuration of photovoltaic (PV) array can influence a simple DC drive performance. Methods: In this study, a simulated investigation is carried out for a PV system consisting of 30 panels arranged in 3*5 and 5*3, 3*6 and 6*3, 5*6, and 6*5 configuration. Two motors of rating 5 HP and 10 HP are used for the simulation. The first category includes the mentioned configuration in which the number of series PV panels (Ns) is higher than the number of the parallel panel (Np) such as 5*3, 6*3, and 6*5. The second category includes the combination in which the number of PV panels connected in parallel is higher, such as 3*5, 3*6, and 5*6. Findings: The performance of the 5HP motor gets increased by 173.36%, and the performance of the 10 HP motor gets risen by 121.26% in 18 PV panel system when Ns is higher than Np. Also, the system’s overall efficiency gets improved when Ns is higher than Np. Novelty: Usually, to vary the performance of the DC motor, power electronics circuitry is implemented. However, the performed simulated result shows that certain configurations will give better performance. Therefore, control for the DC motor’s enhanced performance can be accomplished without the power electronics control system. Keywords: PV array combination; DC motor load; Performance analysis; Simulink-Matlab

Shade dispersion methodologies for performance improvement of classical total cross‐tied photovoltaic array configuration under partial shading conditions

Shade dispersion methodologies for performance improvement of classical total cross‐tied photovoltaic array configuration under partial shading conditions

AN EXPERIMENTAL OPTIMIZATION STUDY OF A PHOTOVOLTAIC SOLAR PUMPING SYSTEM USED FOR SOLAR DOMESTIC HOT WATER SYSTEM UNDER IRAQI CLIMATE

The performance of a photovoltaic solar water pumping system (PVSWPS) promising in a solar water heating system has been studied experimentally. The design of a photovoltaic array configuration can affect the performance of the (PVSWPS), the water pump characteristic, the flow rate of the water and the overall system efficiency. The aim of the present work is to determine an optimum photovoltaic array configuration that can supply a water pump with an optimal amount of energy. Three different photovoltaic array configurations have been tested (4S, 2S ×2P and 4P). The experiments have been carried out in a sunny day, light hours under the conditions of Iraq climate and for a constant head level of 6m. The results showed that the second photovoltaic array configuration (2P × 2S) is suitable to provide an optimal energy. Also, the second photovoltaic array configuration (2P × 2S) that powered the water pump delivered a maximum average water volume (2.298 m3) during the day among the three different configurations.

Power Losses Reduction of Solar PV Systems Under Partial Shading Conditions Using Re-Allocation of PV Module-Fixed Electrical Connections

The paper gives a review of the investigation, which is being imported under different shading scenarios on the solar photovoltaic (PV) array arrangements. Under non-uniform irradiations, the authors pursue voluminous interpretation to scrutinize the mismatch power losses (PL) in PV array systems. In addition to power, the partial shading also reveals non-linearity along with multiple maximum power points (MPP) on performance curves i.e. power-voltage (P-V) and current-voltage (I-V). The inspection of the optimal layout of PV modules during the study helps us to extract maximum power and reduce the number of power peaks, when arranged in an array under partial shading conditions (PSCs). In the vicinity of PV array configurations such as series-parallel (SP), honey-comb (HC), bridge-link (BL), total cross-tied (TCT), and hybrid series-parallel-Total cross-tied (SP-TCT), bridge link-honey comb (BL-HC), and bridge link-total cross-tied (BL-TCT) are considered to investigate the performance under shadowing conditions. Moreover, Latin square (LS) puzzle is introduced to reconfigure the PV array and extensive comprehensive comparison with conventional is presented and entitled as “LS-TCT” configuration. The MATLAB/Simulink environment helps in modelling all the considered PV array configurations. The recommended LS-TCT configuration is turned out to be superior (for MATLAB/Simulink study) among all configurations during PSCs in terms of location of global maximum power point (GMPP), minimized PL and improved fill factor (FF). To show the superiority of proposed Shape-do-Ku (SPDK) puzzle based configuration, an experimental comparison is shown with conventional TCT and LS-TCT, Su-do-Ku (SDK) puzzle based configurations under new shading pattern-4. In addition, presented experimental study is validated the results obtained during MATLAB/Simulink study.

Scenario-Based Investigation on the Effect of Partial Shading Condition Patterns for Different Static Solar Photovoltaic Array Configurations

This paper presents an in-depth analysis and investigation on the performance of static photovoltaic (PV) array configurations subjected to various partial shading conditions (PSCs). Under PSCs, the electrical characteristics of the PV modules are critically monitored and reasons for their behavioral changes are highlighted. By doing so, this study aims to improve the efficiency of PV systems by minimizing mismatch losses and determining the optimum array configuration which is characterized by the highest maximum power and lowest relative losses under PSCs. Besides, this study complements and carries forward the previous studies through the detailed analysis of each configuration subjected to various practically probable PSCs. Three different PV array sizes ( $5\times4$ , $5\times5$ , and $3\times10$ ) are used to analyze the results and performance under considered shading scenarios. MATLAB/Simulink platform is used to model and simulate the PV array using the single diode (5-parameters) model. In-depth analysis of current flow across cross-ties and bypass diodes activation shows that the diagonal shading pattern leads to lower power loss (PL). Besides, the Total Cross-Tied (TCT) configuration demonstrates superior performance under most of the PSCs compared to other configurations. These results provide valuable information about the performance of PV array which may lead to better estimation and prediction of global maximum power (GMP) generation of a PV system.

Adaptive Switch Matrix for PV Module Connections to Avoid Permanent Cross-Tied Link in PV Array System Under Non-Uniform Irradiations

In this paper, the significance of cross-tied link between the solar photovoltaic (PV) modules in an array during partial shading conditions (PSCs) is introduced. In order to conduct a detailed analysis, twenty numbers of 20W PV modules ( 4×5) are arranged in a series-parallel (SP) configuration. The change in the pre-arranged SP configured PV array is implemented using a cross-link matrix switch between parallels based on shadow patterns. The switch matrix based modified PV array configuration is called Adaptive-cross-tied (A-CT) configuration. An embedded system based adaptive switch matrix (ASM) controller is developed to control the cross-linking connections between the PV modules under the PSCs to improve global maximum power. In addition, a performance analysis is carried out and compared all PV modules arranged in conventional SP and A-CT configurations. Moreover, realistic shadow test cases are under consideration to characterize current-voltage (I-V) and power-voltage (P-V) characteristics. The output power of the PV array decreases as well as the P-V curves show multiple power maxima points., such as the local maximum power point (LMPP) and the global maximum power point (GMPP). LMPP and GMPP locations, mismatch loss (ML), enhanced fill factor (FF), decreased power loss (PL) and performance ratio (PR) are indicators of performance during experimental and MATLAB/Simulink studies.

Performance enhancement of photovoltaic array configurations with blocking p-mosfets under partial shading condition

ABSTRACT Being the most abundant renewable source of energy, photovoltaic arrays (PVA) are extensively used for power generation. A number of factors influence performance of the PVAs, among which complete or partial shading of PVAs is perceived as a major concern for the researchers. Complete or partial shading reasonably reduces the output power of PVAs which subsequently leads to multiple maximum power points (MPPs) in the P-V curves. One of its major consequences is reverse power flow, conventionally blocking diodes (BD) based on different configuration are utilized to limit the adverse effects of reverse power flow. This paper proposes a novel scheme to improvise performance of the photovoltaic array configuration (PVAC) under-shaded condition, in which conventionally used BDs are replaced by blocking P-MOSFET (BP-MOS). A comparison study is carried out to determine performance of four different PVAC’s such as series-parallel (SP), total-cross-tied (TCT), bridge-link (BL), and honey-comb (HC) employing BDs as well as BP-MOS. Simulations are accomplished on MATLAB/SIMULINK, in order to analyze practical implications of preferred the PVAC under various illumination conditions (such as horizontal, vertical, and diagonal). Obtained results reveal efficacy of the proposed configuration in terms of least power loss, increased fill factor, and thus maximum efficiency.

Potential assessment of solar power plant: A case study of a small island in Eastern Indonesia

Indonesia as a tropical country has high solar energy potential to generate power. Solar power plant (SPP) using Photovoltaic (PV) is suitable for power generation in a small power system, such as in several small islands in Eastern Indonesia since solar energy is easy to obtain there. The implementation of SPP for power generation needs an examination of energy yield to observe the performance ratio of SPP. Those parameters are important to study to further analyze the economic potential and feasibility of SPP development. This study estimates the performance ratio (PR) and potential energy yield of SPP in a small island in Eastern Indonesia through a self-developed program using MATLAB based Graphical User Interface (GUI). Moreover, this program also provides the levelized cost of energy (LCOE) calculation and land use optimization by readjusting the PV array configuration. According to the simulation result, the implementation of SPP in Eastern Indonesia has 85.4% and 23.54% for annual PR and capacity factor (CF) respectively. The simulation also shows that the optimum distance between PV strings produces higher annual energy yield and CF.

Effect of head and PV array configurations on solar water pumping system

Nowadays, the photovoltaic (PV) to power the water pumps is a newly accepted technology with few challenges associated with high initial cost and lower system efficiency. The literature suggests the majorly of commercial pumps at present, underperform, due to poor system design, low efficiency and mismatch of components. In this paper Matlab Simulink model of a solar photovoltaic (PV) water pumping system (SPVWPS) has been created. Such a model; demonstrates the system characteristics under different operating parameters. This model can successfully and completely check the feasibility, size and optimize the system for its complete utilization. The effect of various parameters such as operating head of the pump, radiation, PV array configurations on the performance of the SPVWPS has been discussed and presented in the paper.

An Improved Feasibility Analysis of Photovoltaic Array Configurations and Reconfiguration Under Partial Shading Conditions

—Globally, the shading phenomenon has been identified as one of the major issues relating to the successful and effective operation of photovoltaic (PV) system. Shading can be due to neighboring development, passing mists, fowls or winged animals’ litter, etc. that will decrease the generation of PV system. The PV generations under partial shading can be enhanced by suitably selecting PV array configuration and reconfiguration schemes. This article provides an extensive investigation of various PV array configurations and reconfiguration operating in partial shading conditions. The competence with reference to maximum power output, shading losses, fill factor, and mismatch losses of PV array configuration, i.e., Series-Parallel (SP), Honey-Comb (HC), Total Cross Tied (TCT), Bridge-linked (BL), and reconfiguration namely; Odd–Even (OE) are evaluated for four different shading case studies. The results are compared with 7 × 7 PV array configuration for the same shading cases. The investigation is expanded to identify the outcomes of incorporating a bypass diode in each module on power output. The investigations carried out also reveal that the shading scenario decides the maximum instantaneous power output of PV array. The outcomes exhibit that OE reconfiguration provides improved performance concerning to maximum power generation for all considered shading case studies.

Analysis of partial shading effect on energy output of different solar PV array configurations

As per the energy efficiency concern, partial shading is a prevalent problem in the photovoltaic (PV) system. In partial shading condition, cells or modules of the PV array receives various levels of solar irradiance. Partial shading conditions instigate the mismatch in the PV electrical characteristics and it induces the degradation in PV output energy. The amount of mismatch depends upon various aspects such as array size, configuration type and shading patterns. This paper presents the comparative analysis of partial shading effect on a 6 × 6 PV array configurations like series–parallel (SP), total-cross-tied (TCT), bridge-linked (BL), honey-comb (HC). The performance of different array configurations is studied through MATLAB-Simulink and compared in terms of fill-factor (FF), maximum power (Pgmp), mismatch loss, voltage at maximum power (Vmp) and current at maximum power (Imp) values.

Experimental investigations on the seasonal performance variations of directly coupled solar photovoltaic water pumping system using centrifugal pump

Optimum sizing and type of photovoltaic array configuration (PVAC) greatly affect the performance of solar photovoltaic water pumping system (SPVWPS). The electric power is decided considering the daily volume of pumped water and the total dynamic head at pumping site. In addition, however, the electric power output of PVAC also depends upon latitude, inclination angle of panel, and seasonal parameters like radiation and temperature, etc. In the present work, experimental investigations have been done to select the optimum PVAC to supply electric power to SPVWPS and effect of seasonal variations on its output. This has been done by investigating the performance of SPVWPS employing a direct current (DC) borehole centrifugal submersible pump along with different PVACs namely PVAC1 (4S × 2P), PVAC2 (5S × 2P), PVAC3 (7S), PVAC4 (8S), PVAC5 (3S × 2P) and PVAC6 (6S) at four pumping heads 2, 3, 4 and 5 bar. 4S × 2P indicates: 2 strings of photovoltaics (PV) module are connected in parallel where each string consists of 4 PV modules connected in series. Similarly, 8S indicates 8 PV modules are connected in series only. The seasonal variations in output of SPVWPS and selection of optimum PVAC have been done by testing in winter and summer seasons in the laboratory under the outdoor conditions of VNIT, Nagpur, India. Through the study, it can be concluded that PVAC2 (5S × 2P) delivered maximum discharge in winter season and PVAC4 (8S) in summer season at all pumping heads.