scholarly journals Current Flow Analysis of PV Arrays under Voltage Mismatch Conditions and an Inverter Failure

2019 ◽  
Vol 9 (23) ◽  
pp. 5163 ◽  
Author(s):  
Woo Gyun Shin ◽  
Jong Rok Lim ◽  
Gi Hwan Kang ◽  
Young Chul Ju ◽  
Hye Mi Hwang ◽  
...  

In PV (Photovoltaic) systems, the PV array is a structure in which many PV strings are connected in parallel. The voltage mismatch between PV strings, in which PV modules are connected in a series, occurs due to a voltage decrease in some modules. In this paper, research on the electrical characteristics of PV arrays due to a voltage mismatch was conducted. Considering the voltage mismatch, experiments on partial shading, the non-uniformity of irradiance, and the failure of bypass diodes were conducted on the PV module level. It was confirmed that the open-circuit voltage greatly decreased due to the failure of bypass diodes, which is among the causes of voltage mismatch. From the simulation results at the PV array level, it can be seen that a reverse current flowed into the low-potential string, which includes PV modules, causing the failure of the bypass diodes. Measuring the reverse current at one low-potential string, it was found that, in four parallel circuits, the reverse current was 12 A. For this reason, in large PV plants, an overcurrent can flow into the fuse due to the potential difference between strings, causing an output decrease of PV plants and the burnout of fuses.

2015 ◽  
Vol 781 ◽  
pp. 267-271
Author(s):  
Santisouk Phiouthonekham ◽  
Anucha Lekkruasuwan ◽  
Surachai Chaitusaney

The impact of partial shading on photovoltaic (PV) array is discussed in this paper. The partial shading on PV array can significantly decrease the power generation of PV array. This study examines the modeling of PV module which relates with solar irradiation, temperature, and shading pattern. There are different shading patterns on PV array, such as one-string shading, two-strings shading, and much more. The characteristics of current-voltage (I-V) and voltage-power (V-P) curves for each individual the PV array can be different dependent on the multiple MPPs, maximum power points (MPPs). These multiple MPPs are basically lower than the MPP in case of no shading. Therefore, the total generated energy in an interested time period is usually reduced. As a result, this paper proposes the appropriate arrangement of PV modules in a PV array in order to mitigate the impact of partial shading. Finally, the proposed arrangement of PV modules is tested in a testing system. All the obtained results confirms that the proposed arrangement of PV modules is effective and can be applied in practice.


Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3216 ◽  
Author(s):  
Manoharan Premkumar ◽  
Umashankar Subramaniam ◽  
Thanikanti Sudhakar Babu ◽  
Rajvikram Madurai Elavarasan ◽  
Lucian Mihet-Popa

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.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2308
Author(s):  
Kamran Ali Khan Niazi ◽  
Yongheng Yang ◽  
Tamas Kerekes ◽  
Dezso Sera

Partial shading affects the energy harvested from photovoltaic (PV) modules, leading to a mismatch in PV systems and causing energy losses. For this purpose, differential power processing (DPP) converters are the emerging power electronic-based topologies used to address the mismatch issues. Normally, PV modules are connected in series and DPP converters are used to extract the power from these PV modules by only processing the fraction of power called mismatched power. In this work, a switched-capacitor-inductor (SCL)-based DPP converter is presented, which mitigates the non-ideal conditions in solar PV systems. A proposed SCL-based DPP technique utilizes a simple control strategy to extract the maximum power from the partially shaded PV modules by only processing a fraction of the power. Furthermore, an operational principle and loss analysis for the proposed converter is presented. The proposed topology is examined and compared with the traditional bypass diode technique through simulations and experimental tests. The efficiency of the proposed DPP is validated by the experiment and simulation. The results demonstrate the performance in terms of higher energy yield without bypassing the low-producing PV module by using a simple control. The results indicate that achieved efficiency is higher than 98% under severe mismatch (higher than 50%).


2021 ◽  
Vol 13 (9) ◽  
pp. 5027
Author(s):  
Wenjie Zhang ◽  
Tongdan Gong ◽  
Shengbing Ma ◽  
Jianwei Zhou ◽  
Yingbo Zhao

In building integrated photovoltaics (PV), it is important to solve the heat dissipation problem of PV modules. In this paper, the computational fluid dynamics (CFD) method is used to simulate the flow field around the open-joint photovoltaic ventilated double-skin façades (OJ-PV-DSF) to study the influence of the mounting dimensions (MD) of a PV array on the module temperature. The typical summer afternoon meteorological parameters, such as the total radiation (715.4 W/m2), the outdoor temperature (33.1 °C), and the wind speed (2.0 m/s), etc., are taken as input parameters. With the DO (discrete ordinates) model and the RNG (renormalization-group) k − ε model, a steady state calculation is carried out to simulate the flow of air in and around the cavity under the coupling of hot pressure and wind pressure, thereby obtaining the temperature distribution of the PV array and the wall. In addition, the simulation results are compared with the onsite experimental data and thermal imaging to verify the accuracy of the CFD model. Then three MD of the open joints are discussed. The results show that when the a value (represents the distance between PV modules and wall) changes from 0.05 to 0.15, the temperature drop of the PV module is the most obvious, reaching 2.0 K. When the b value (representing the distance between two adjacent PV modules in the vertical direction) changes from 0 to 0.1, the temperature drop of the PV module is most obvious, reaching 1 K. When the c value (represents the distance between two adjacent PV modules in the horizontal direction) changes from 0 to 0.1, the temperature of the PV module is lowered by 0.8 K. Thus, a = 0.1–0.15, b = 0.1 and c = 0.1 are recommended for engineering applications to effectively reduce the module temperature.


2018 ◽  
Vol 7 (1.8) ◽  
pp. 172 ◽  
Author(s):  
G Sreenivasa Reddy ◽  
T Bramhananda Reddy ◽  
M Vijaya Kumar

The PV array generates smaller amount of the power compared with other electrical power generation components. There are many components that are adversely effected the output of PV array in such components, one is partial shading. Due to this, each module in PV array receives different solar irradiations causes different P-V characteristics of its peak values. This paper presents a pioneering method called as Magic Square configuration has been proposed to enhance the generated power of photovoltaic modules by configuring those are under affect of shade. Thus there is no change of electrical arrangement of PV modules in an array but only the objective location in the total cross tied (TCT) array is rearranged according to the magic square arrangement. Proposed paper gives comparison data with the conventional configuration method and hence the performance is calculated. The proposed technique provides a better solution that how shadow effect on the PV  modules has been reduced and how this shadow is distributed, and not only that also gives an idea  about how the inequality losses due to the partial shading is effectively reduced. The power loss of  various configurations of 3X3 and 4X4 array has been compared. The proposed technique is validated through MATLAB/Simulink environment. 


2015 ◽  
Vol 16 (1) ◽  
pp. 15-21 ◽  
Author(s):  
B. Chitti Babu ◽  
Suresh Gurjar ◽  
Ashish Meher

Abstract Generally, the characteristics of photovoltaic (PV) array are largely affected by solar temperature, solar irradiance, shading patterns, array configuration and location of shading modules. Partial shading is due to moving clouds and shadows of nearby obstacles and can cause a significant degradation in the output of PV system. Hence, the characteristics of PV array get more multifaceted with multiple peaks. The ultimate aim of the paper is to analyze the performance of PV module during such adverse condition based on simplified two-diode model. To reduce the computational time, the simplified two-diode model has a photocurrent source in parallel with two ideal diodes. Only four parameters are required to be calculated from datasheet in order to simulate the model. Moreover, the performance of PV array is evaluated at different shaded patterns and it is found that the model has less computational time and gives accurate results.


Author(s):  
Santosh Kumar Singh ◽  
Anurag Singh Yadav ◽  
Ashutosh Srivastava ◽  
Amarjeet Singh

In this paper, a detailed study is carried out on the solar photovoltaic (PV) array topologies under various shading patterns. The aim of this study is to investigate the mismatch effect losses in PV modules for non uniform irradiations. The shading causes not only power losses, but also non-linearity of P-V characteristics. Under partial shaded conditions, the P-V and I-V characteristics exhibit extreme non-linearity along with multiple load maxima. In this paper, the investigations of the optimal layout of PV modules in a PV array are worked out to provide maximum output power under various shaded conditions. Three type of solar PV array topologies e.g. Series-parallel (SP), Total cross tied (TCT) and Bridge link (BL) are considered for various typesof shaded patterns. The modeling of solar PV array for various types of topologies is done in MATLAB/Simulink environment. The extensive results have been taken on these topologies for partial shading patterns and analyzed, which proves the TCT topology performance is better as compared to other topologies for most of the shading patterns.


The electrical power generation from solar photo voltaic arrays increases by reducing partial shading effect due to the deposition of dust in modules, shadow of nearby buildings, cloud coverage leads to mismatching power losses. This paper gives the detailed analysis of modeling, simulation and performance analysis of different 4x4 size PV array topologies under different irradiance levels and to extract output power of panels maximum by reducing the mismatching power losses. For this analysis, a comparative study of six PV array topologies are Series, Parallel, Series-Parallel, Total-Cross-Tied, Bridge Linked and Honey-Comb are considered under various shading conditions such as one module shading, one string shading, zigzag type partial shading and total PV array partially shaded cases. The performance of above six topologies are compare with mismatching power losses and fill-factor. For designing and simulation of different PV array configurations/topologies in MaTLab/Simulink, the LG Electronics LG215P1W PV module parameters are used in all PV modules.


ACTA IMEKO ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 93
Author(s):  
Giovanni Bucci ◽  
Fabrizio Ciancetta ◽  
Edoardo Fiorucci ◽  
Antonio Delle Femine

<p class="Abstract">Shading is one of the most critical factors that produces a reduction in power in photovoltaic (PV) modules. The main causes of shading are related to cloud cover; local specificity; natural characteristics; building and other civil works; and the presence of the PV system itself. A reduction in overall radiation produces a consequent reduction in electric power. Another more problematic effect is associated with the partial shading of the PV modules. The shaded cell behaves as a load, dissipating energy and increasing its temperature. This effect can involve irreversible changes to the PV module, with a decrease in performance that can even cause the destruction of the shaded cell.</p><p>The main aim of this work is the development of a testing procedure for the performance evaluation of commercial PV modules in the presence of partial shading on one cell. Tests were carried out using thermographic and electric measurements and by varying the shading levels according to IEC standards. Shading up to total darkening is achieved by means of a number of filters that reduce the direct solar irradiance.</p><p>As a case study, a complete characterisation of a 180 Wp polycrystalline PV module was performed according to the proposed testing procedure, showing that high temperatures can be measured on the shaded PV module surface even if only 50 % of the surface of one cell of the PV module is darkened.</p>


Author(s):  
Faisal Saeed ◽  
Haider Ali Tauqeer ◽  
Hasan Erteza Gelani ◽  
Muhammad Hassan Yousuf

Partial shading on solar photovoltaic (PV) arrays is a prevalent problem in photovoltaic systems that impair the performance of PV modules and is responsible for reduced power output as compared to that in standard irradiance conditions thereby resulting in the appearance of multiple maximas on panel output power characteristics. These maxims contribute to mismatch power losses among PV modules. The mismatch losses depend on shading characteristics together with different interconnected configuration schemes of PV modules. The research presents a comparative analysis of partial shading effects on a 4 x4 PV array system connected in series(S), parallel (P), serries-parallel (SP),total-cross-tied (TCT),central-cross-tied(CCT),bridge-linked(BL),bridge-linked total cross-tied (BLTCT) ,honey-comb(HC), honey-comb total-cross-tied (HCTCT) and ladder (LD) configurations using MATLAB/Simulink. The PV module SPR-X20-250-BLK was used for modeling and simulation analysis. Each module is comprised of 72 number of PV cells and a combination of 16 PV modules was employed for the contextual analysis. Accurate mathematical modeling for the HCTCT configuration under partial shading conditions (PSCs) is provided for the first time and is verified from the simulation. The different configuration schemes were investigated under short-narrow,short-wide,long-narrow,long-wide, diagonal, entire row distribution, and entire column distribution partial shading condition patterns with mathematical implementation and simulation of passing clouds. The performance of array configurations is compared in terms of maximum power generated ), mismatch power loss (∆), relative power loss ) and the fill factor (FF). It was inferred that on average, TCT configuration yielded maximum power generation under all shading patterns among all PV modules interconnection configurations with minimum mismatch power losses followed by hybrid and conventional PV array configurations respectively.


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