An Approach to improve the Performance of Total Cross-tied connected PV array in Partial shading condition

Due to the partial shading condition (PSC) in solar PV systems, performance degrades to a large extent. To overcome from this problem bypass diode is used which creates the problem of multiple local maxima. Therefore, total cross-tied (TCT) connection is introduced in the literature, which improves the performance of PV systems in PSC without using bypass diode. But the performance improvement in TCT connection is also limited. Because for some particular shading pattern the efficiency cannot be improved beyond a certain limit. In line with this, an algorithm is proposed in this paper through which the performance of a PV array can be improved. Here, the performance of a PV array is improved by distributing the shading effect on the entire PV array, which reduces the mismatch losses and to enhance the power output of the PV array

A hierarchical architecture for increasing efficiency of large photovoltaic plants under non-homogeneous solar irradiation

Under non-homogeneous solar irradiation, photovoltaic (PV) panels receive different solar irradiance, resulting in a decrease in efficiency of the PV generation system. There are a few technical options to fix this issue that goes under the name of mismatch. One of these is the reconfiguration of the PV generation system, namely changing the connections of the PV panels from the initial configuration to the optimal one. Such technique has been widely considered for small systems, due to the excessive number of required switches. In this paper, the authors propose a new method for increasing the efficiency of large PV systems under non-homogeneous solar irradiation using Series-Parallel (SP) topology. In the first part of the paper, the authors propose a method containing two key points: a switching matrix to change the connection of PV panels based on SP topology and the proof that the SP-based reconfiguration method can increase the efficiency of the photovoltaic system up to 50%. In the second part, the authors propose the extension of the method proposed in the first part to improve the efficiency of large solar generation systems by means of a two-levels architecture to minimize the cost of fabrication of the switching matrix

Performance Enhancement of a Partially Shaded Photovoltaic Array by Optimal Reconfiguration and Current Injection Schemes

The output of a photovoltaic array is reduced considerably when PV panels are shaded even partially. The impact of shading causes an appreciable loss in power delivery, since the PV panels are connected in series and parallel to contribute to the required voltage and power for the load. The prevailing research on mitigating the shading impact is mostly based on complex reconfiguration strategies where the PV panels are subjected to complex rewiring schemes. On the other hand, to disperse the shading many studies in the literature defend the physical rearrangement of the panels. The available intensive reconfiguration schemes, such as the series parallel (SP), bridge link (BL), honeycomb (HC), and total cross tied (TCT) schemes, try only to mitigate the shading impact and there is no scope for compensation; as a result, a loss of output power is inevitable. In the proposed research work, both the mitigation of and the compensation for the losses incurred due to shading are studied. In this work, an optimal reconfiguration scheme is adopted to reduce the shading impact and a power electronic circuit with a battery source is designed to compensate for the shading losses in all aspects. In the optimal reconfiguration scheme, a bifurcation strategy is adopted in each column and the electrical connections of the PV panels are interchanged such that the shading impact is dispersed. The power electronic circuit consists of a half-bridge buck converter with a battery source that injects the current required by a shaded column. This setup compensates for the shaded PV array’s power and improves the efficiency of the total system. The proposed scheme was implemented in a 3200 W system and subjected to various shading patterns, including single panel shading, corner shading, long and wide shading, and random shading. The proposed scheme was simulated in the MATLAB Simulink environment and compared with static 4 × 4 PV array configurations, including the series parallel (SP), bridge link (BL), honeycomb (HC), and total cross tied (TCT) configurations. The comparative performance was assessed in terms of mismatch power loss, fill factor, and efficiency. The proposed system is suitable for all shading patterns and was proved to be very efficient even in the worst shading, where 1353 W was saved

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.Citation: Bala Raju, V., and Chengaiah, C. (2021). Enhance the Output Power of a Shaded Solar Photovoltaic Arrays with Shade Dispersion based TCT Configuration. Trends in Renewable Energy, 7, 1-23. DOI: 10.17737/tre.2021.7.1.0012

A Comprehensive Study on Re-arrangement of Modules Based TCT Configurations of Partial Shaded PV Array with Shade Dispersion Method

The conventional Total-Cross-Tied (TCT) Solar photovoltaic (SPV) array configuration has the highest power output as compared to other configurations or topologies in most cases of partial shading. But the performance of TCT configuration is affected under shading conditions, resulting in multiple peaks occurring in the output PV characteristics. To improve the performance of TCT array configuration under different shading scenarios, it is only necessary to reposition or rearrange the PV modules in the TCT Solar PV array based on the arrangement of puzzle numbers, without altering the electrical contacts of the TCT array configuration. The main objective of this study is to investigate the performance of rearrangement of modules in SPV array based new TCT array configurations with shade dispersion technique and compare the global maximum peak power (GMPP) of SPV array, mismatch losses, Fill-Factor, efficiency and number of required electrical connections or ties between array modules with proposed optimal arrangement of modules under shading (non-uniform irradiance) conditions. For this study, one uniform irradiance case and total 14 partial shading patterns were considered. MATLAB/Simulink software was used for modeling and simulation of 6×6 size different rearrangement based TCT array and proposed optimal SPV array configurations.Citation: BALARAJU, V., and Chengaiah, C. (2020). A Comprehensive Study on Re-arrangement of Modules Based TCT Configurations of Partial Shaded PV Array with Shade Dispersion Method. Trends in Renewable Energy, 6, 37-60. DOI: 10.17737/tre.2020.6.1.0011

Evaluation of Mathematical Model to Characterize the Performance of Conventional and Hybrid PV Array Topologies under Static and Dynamic Shading Patterns

The analysis and the assessment of interconnected photovoltaic (PV) modules under different shading conditions and various shading patterns are presented in this paper. The partial shading conditions (PSCs) due to the various factors reduce the power output of PV arrays, and its characteristics have multiple peaks due to the mismatching losses between PV panels. The principal objective of this paper is to model, analyze, simulate and evaluate the performance of PV array topologies such as series-parallel (SP), honey-comb (HC), total-cross-tied (TCT), ladder (LD) and bridge-linked (BL) under different shading patterns to produce the maximum power by reducing the mismatching losses (MLs). Along with the conventional PV array topologies, this paper also discusses the hybrid PV array topologies such as bridge-linked honey-comb (BLHC), bridge-linked total-cross-tied (BLTCT) and series-parallel total-cross-tied (SPTCT). The performance analysis of the traditional PV array topologies along with the hybrid topologies is carried out during static and dynamic shading patterns by comparing the various parameters such as the global peak (GP), local peaks (LPs), corresponding voltage and current at GP and LPs, fill factor (FF) and ML. In addition, the voltage and current equations of the HC configuration under two shading conditions are derived, which represents one of the novelties of this paper. The various parameters of the SPR-200-BLK-U PV module are used for PV modeling and simulation in MATLAB/Simulink software. Thus, the obtained results provide useful information to the researchers for healthy operation and power maximization of PV systems.publishedVersio

Contribution au Développement de Techniques de Recherche de la Topologie Optimale d’un Générateur Photovoltaïque

This thesis proposes a generalized technique to minimize power losses of PV arrays connected in Total Cross-Tied (TCT), under both current and voltage mismatch effects. The proposed method is based on the classification of the electrical data of the PV modules composing the photovoltaic array in order to identify the mismatch type, then applying an arrangement of the PV modules according to the mismatch type found. The design process of the proposed algorithm is detailed and its validity and performance are verified under different mismatch scenarios. The efficiency enhancement is verified for different mismaths cases and the computed results reveal that the proposed algorithm can achieve a great improvement in the PV array power. Furthermore, a comparative study with SuDoKu and genetic algorithms (GA) are performed. The obtained results under highlighted the superiority of the proposed method in comparison to the compared ones. The enhancement resides in the implementation simplicity as well as in the minimization of the number of infection points indicating smooth I-V and P-V characteristic curves

Modified Series-Parallel Photovoltaic Configuration to Enhance Efficiency under Partial Shading

Partial shading is a phenomenon where photovoltaics (PV) array experiences irregular level of irradiances. Such mismatch can cause a significant reduction in power yield. To mitigate the effect of partial shading, PV modules in an array are connected in various configurations namely Series-Parallel (SP), Total-Cross-Tied (TCT), Bridge-Linked (BL) and Honey-Comb (HC) etc. However, all these techniques introduce redundancy and complexity while improving the performance by very little. In this paper, a new PV configuration is proposed to solve the limitations of the existing PV configurations. The proposed configuration is a modified version of SP, hence referred as MSP configuration. To justify the performance of the proposed scheme, several experiments have been carried in MATLAB Simulink. Total 14 partial shading cases are simulated to compare the output performance between generic SP and proposed MSP configuration. The proposed MSP configuration is validated to be superior compared to normal SP configuration under majority of the cases. Depending on shading pattern, the efficiency of the PV array can be enhanced up to 37%, if MSP configuration is implemented

A comprehensive review on PV configurations to maximize power under partial shading

Partial shading is the condition where PV array experiences different level of irradiances on it which results significant reduction in output power. To handle that issue, PV modules are connected in various configurations as reported in the literature. Different connection schemes of the PV modules provide alternative paths to current flow that eventually improve power attainment under partial shading. A comprehensive study of literature shows that PV modules are connected under different schemes namely simple series (SS), parallel (P), series-parallel (SP), total-cross-tied (TCT), bridge-linked (BL) and honey-comb (HC). In this paper, a comprehensive review is performed to highlight the advantages and limitations of each scheme. To validate the findings from literature review, several experiments are carried out on various configurations in MATLAB Simulink. Three different cases namely unshaded, corner shaded and centre shaded conditions are used in the experiments to analyse the output characteristics. The superiority of various configurations in distinct operating conditions is demonstrated by comparing their maximum power output, relative power loss and fill factor. Based on the results, several recommendations are made on how to handle partial shading by using different PV configurations