Analytical Modeling and Prediction of Global Peak for Partial Shading of PV Modules for a PV System

A grid connected solar photovoltaic (PV) research facility equipped with comprehensive climatic and electric measuring systems has been designed and built in the Department of Electrical Engineering of the Tampere University of Technology (TUT). The climatic measuring system is composed of an accurate weather station, solar radiation measurements, and a mesh of irradiance and PV module temperature measurements located throughout the solar PV facility. Furthermore, electrical measurements can be taken from single PV modules and strings of modules synchronized with the climatic data. All measured parameters are sampled continuously at 10 Hz with a data-acquisition system based on swappable I/O card technology and stored in a database for later analysis. The used sampling frequency was defined by thorough analyses of the PV system time dependence. Climatic and electrical measurements of the first operation year of the research facility are analyzed in this paper. Moreover, operation of PV systems under partial shading conditions caused by snow and building structures is studied by means of the measured current and power characteristics of PV modules and strings.

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A Simple Method for Detecting Partial Shading in PV Systems

Energies ◽

10.3390/en14164938 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4938

Author(s):

Waleed Al Abri ◽

Rashid Al Abri ◽

Hassan Yousef ◽

Amer Al-Hinai

Keyword(s):

Accurate Method ◽

Maximum Power ◽

Global Maximum ◽

Pv System ◽

Maximum Power Point ◽

Simple Method ◽

Partial Shading ◽

Pv Systems ◽

Power Point ◽

Global Peak

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.

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Thermographic and electrical characterization of a photovoltaic panel under partial shading conditions: a case study

ACTA IMEKO ◽

10.21014/acta_imeko.v8i1.609 ◽

2019 ◽

Vol 8 (1) ◽

pp. 93

Author(s):

Giovanni Bucci ◽

Fabrizio Ciancetta ◽

Edoardo Fiorucci ◽

Antonio Delle Femine

Keyword(s):

Electrical Characterization ◽

Testing Procedure ◽

Pv System ◽

Partial Shading ◽

Photovoltaic Panel ◽

Pv Module ◽

Pv Modules ◽

Consequent Reduction

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.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.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.

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Modelling and Analysis of Photovoltaic System under Partially Shaded Conditions using Improved Harmony Search Algorithm

Nigerian Journal of Technological Development ◽

10.4314/njtd.v17i4.4 ◽

2021 ◽

Vol 17 (4) ◽

pp. 269-277

Author(s):

S. Sani ◽

G.A. Olarinoye ◽

P.U. Okorie

Keyword(s):

Search Algorithm ◽

Harmony Search ◽

Harmony Search Algorithm ◽

Photovoltaic System ◽

Pv System ◽

Partial Shading ◽

Excessive Heat ◽

Improved Harmony Search ◽

Improved Harmony Search Algorithm ◽

Global Peak

With the increasing penetration of solar electricity in residential, institutional and commercial centres around the globe, the phenomenon of partial shading (PS) in Photovoltaic (PV) power generation is gaining attention. Under Partial shading condition (PSC), cells that are shaded tends to have an equivalent current with cells that are unshaded in series-connection, due to this, the shaded cells operates in reverse bias and consequently becomes load and consumes the generated power. This causes a serious problem known as hotspot. This is characterized by the presence of excessive heat which consequently reduces the total generated power. Recently, researchers use the technique of bypass diodes across the PV cells so that the problem of partial shading can be reduced, but this solution taken alone, has made the nonlinearity and complexity of the system to increase. The shaded cells generate multiple peaks with only one global peak. Conventional Maximum Power Point Tracking (MPPT) algorithms do not differentiates the global peak from local peaks which may end up tracking local peak as global peak, this results in serious power loss. This paper seeks to solve this problem by modelling a PV system under PSC and through the application of Improved Harmony Search algorithm (IHSA) and variable step Perturb & Observe (P&O) to track the global peak instead of local peaks. Simulation was done in MATLAB/Simulink 2018a environment, and the results under standard test condition (STC) and PSC showed that the proposed IHSA had an improvement of 25%, 3.17% and 2.27%, 3.07% and 2.21%, 3.26% and 2.26% when compared with the improved particle swarm optimization (IPSO) under STC and PSC conditions respectively, which had a better advantage of minimizing power oscillation and improving the efficiency of the system, improved MPPT tracking, reduced error and a better tracking efficiency in both conditions. Keywords: MPPT, photovoltaic system, partial shading, tracking efficiency, Harmony search algorithm

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Power dissipation analysis of PV module under partial shading

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v11i2.pp1029-1035 ◽

2021 ◽

Vol 11 (2) ◽

pp. 1029

Author(s):

Byunggyu Yu ◽

Seok-Cheol Ko

Keyword(s):

Power Dissipation ◽

Input Voltage ◽

Maximum Power ◽

Pv System ◽

Partial Shading ◽

Point Tracking ◽

Pv Inverter ◽

Pv Module ◽

Pv Modules ◽

Total Maximum

Photovoltaic (PV) generation has been growing dramatically over the last years and it ranges from small, rooftop-mounted or building integrated systems, to large utility scale power stations. Especially for rooftop-mounted PV system, PV modules are serially connected to match with PV inverter input voltage specification. For serially connected PV system, shading is a problem since the shaded PV module reduces the output whole string of PV modules. The excess power from the unshaded PV module is dissipated in the shaded PV module. In this paper, power dissipation of PV module under partial shading is analyzed with circuit analysis for series connected PV modules. The specific current and voltage operating point of the shaded PV module are analyzed under shading. PSIM simulation tool is used to verify the power dissipation analysis. When there is no bypass diode and three solar modules are connected in series, upto 39.1% of the total maximum PV power is dissipated in the shaded PV module. On the other hand, when the bypass is attached, 0.3% of the total maximum power is generated as a loss in the shaded PV module. The proposed analysis technique of shaded PV module could be used in PV system performance analysis, especially for maximum power point tracking (MPPT) performance.

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

Energies ◽

10.3390/en13123216 ◽

2020 ◽

Vol 13 (12) ◽

pp. 3216 ◽

Cited By ~ 9

Author(s):

Manoharan Premkumar ◽

Umashankar Subramaniam ◽

Thanikanti Sudhakar Babu ◽

Rajvikram Madurai Elavarasan ◽

Lucian Mihet-Popa

Keyword(s):

Mathematical Model ◽

Performance Analysis ◽

Fill Factor ◽

Partial Shading ◽

Pv Systems ◽

Pv Array ◽

Pv Module ◽

Pv Modules ◽

Power Maximization ◽

Global Peak

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.

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Simulations and dSPACE Real-Time Implementation of Photovoltaic Global Maximum Power Extraction under Partial Shading

Sustainability ◽

10.3390/su12093652 ◽

2020 ◽

Vol 12 (9) ◽

pp. 3652

Author(s):

Fahd A. Alturki ◽

Abdullrahman A. Al-Shamma’a ◽

Hassan M. H. Farh

Keyword(s):

Cuckoo Search ◽

Maximum Power ◽

Global Maximum ◽

Pv System ◽

Maximum Power Point ◽

Partial Shading ◽

Power Extraction ◽

Maximum Power Point Tracker ◽

Power Point ◽

Global Peak

Under partial shading conditions (PSCs), solar photovoltaic (PV) energy systems generate multiple peaks; one global peak (GP) and several local peaks (LPs). Thus, tracking the GP of the PV systems under PSCs is necessary to enhance the system reliability and efficiency. Conventional maximum power point tracker (MPPT) algorithms are capable of tracking the unique peak under uniform conditions but they fail to track the GP under PSCs. To the best of our knowledge, this paper represents the first study that introduces a comprehensive comparison of three efficient maximum power point tracker (MPPT) algorithms that are used to extract the GP of the PV system under both uniform and PSCs. These MPPT techniques include two metaheuristic techniques, which are cuckoo search optimization (CSO) and particle swarm optimization (PSO) techniques in addition to one conventional MPPT; perturb and observe (P&O). Although the simulation and dSPACE-based experimental results demonstrated the superiority of CSO and PSO in tracking the GP, CSO requires less tracking time and thus provides a higher efficiency than the PSO. In addition, P&O can be used to follow the first peak, regardless if it is a local peak or global peak with notable oscillation.

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Techno-Economic Viability of Agro-Photovoltaic Irrigated Arable Lands in the EU-Med Region: A Case-Study in Southwestern Spain

Agronomy ◽

10.3390/agronomy11030593 ◽

2021 ◽

Vol 11 (3) ◽

pp. 593

Author(s):

Guillermo P. Moreda ◽

Miguel A. Muñoz-García ◽

M. Carmen Alonso-García ◽

Luis Hernández-Callejo

Keyword(s):

Crop Yield ◽

Production Costs ◽

Total Production ◽

Early Potato ◽

Pv System ◽

Partial Shading ◽

Processing Tomato ◽

Mediterranean Countries ◽

Pv Modules ◽

Yield Penalty

Solar photovoltaic (PV) energy is positioned to play a major role in the electricity generation mix of Mediterranean countries. Nonetheless, substantial increase in ground-mounted PV installed capacity could lead to competition with the agricultural use of land. A way to avert the peril is the electricity-food dual use of land or agro-photovoltaics (APV). Here, the profitability of a hypothetical APV system deployed on irrigated arable lands of southwestern Spain is analyzed. The basic generator design, comprised of fixed-tilt opaque monofacial PV modules on a 5 m ground-clearance substructure, featured 555.5 kWp/ha. Two APV shed orientations, due south and due southwest, were compared. Two 4-year annual-crop rotations, cultivated beneath the heightened PV modules and with each rotation spanning 24 ha, were studied. One crop rotation was headed by early potato, while the other was headed by processing tomato. All 9 crops involved fulfilled the two-fold condition of being usually cultivated in the area and compatible with APV shed intermitent shading. Crop revenues under the partial shading of PV modules were derived from official average yields in the area, through the use of two alternative sets of coefficients generated for low and high crop-yield shade-induced penalty. Likewise, two irrigation water sources, surface and underground, were compared. Crop total production costs, PV system investment and operating costs and revenues from the sale of electricity, were calculated. The internal rates of return (IRRs) obtained ranged from a minimum of 3.8% for the combination of southwest orientation, early-potato rotation, groundwater and high shade-induced crop-yield penalty, to a maximum of 5.6% for the combination of south orientation, processing-tomato rotation, surface water and low shade-induced crop-yield penalty.

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Reconfigurable Distributed Power Electronics Technique for Solar PV Systems

Electronics ◽

10.3390/electronics10091121 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1121

Author(s):

Kamran Ali Khan Niazi ◽

Yongheng Yang ◽

Tamas Kerekes ◽

Dezso Sera

Keyword(s):

Energy Yield ◽

Solar Pv ◽

Charge Redistribution ◽

Pv System ◽

Partial Shading ◽

Pv Systems ◽

Simulation Based ◽

In Series ◽

A Cell ◽

Power Balancing

A reconfiguration technique using a switched-capacitor (SC)-based voltage equalizer differential power processing (DPP) concept is proposed in this paper for photovoltaic (PV) systems at a cell/subpanel/panel-level. The proposed active diffusion charge redistribution (ADCR) architecture increases the energy yield during mismatch and adds a voltage boosting capability to the PV system under no mismatch by connected the available PV cells/panels in series. The technique performs a reconfiguration by measuring the PV cell/panel voltages and their irradiances. The power balancing is achieved by charge redistribution through SC under mismatch conditions, e.g., partial shading. Moreover, PV cells/panels remain in series under no mismatch. Overall, this paper analyzes, simulates, and evaluates the effectiveness of the proposed DPP architecture through a simulation-based model prepared in PSIM. Additionally, the effectiveness is also demonstrated by comparing it with existing conventional DPP and traditional bypass diode architecture.

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Maximum Power Point Tracking of PV Systems under Partial Shading Conditions Based on Opposition-Based Learning Firefly Algorithm

Sustainability ◽

10.3390/su13052656 ◽

2021 ◽

Vol 13 (5) ◽

pp. 2656

Author(s):

Ahmed G. Abo-Khalil ◽

Walied Alharbi ◽

Abdel-Rahman Al-Qawasmi ◽

Mohammad Alobaid ◽

Ibrahim M. Alarifi

Keyword(s):

Firefly Algorithm ◽

Maximum Power ◽

Pv System ◽

Maximum Power Point ◽

Partial Shading ◽

Point Tracking ◽

Opposition Based Learning ◽

Power Point Tracking ◽

Convergence Process ◽

Power Point

This work presents an alternative to the conventional photovoltaic maximum power point tracking (MPPT) methods, by using an opposition-based learning firefly algorithm (OFA) that improves the performance of the Photovoltaic (PV) system both in the uniform irradiance changes and in partial shading conditions. The firefly algorithm is based on fireflies’ search for food, according to which individuals emit progressively more intense glows as they approach the objective, attracting the other fireflies. Therefore, the simulation of this behavior can be conducted by solving the objective function that is directly proportional to the distance from the desired result. To implement this algorithm in case of partial shading conditions, it was necessary to adjust the Firefly Algorithm (FA) parameters to fit the MPPT application. These parameters have been extensively tested, converging satisfactorily and guaranteeing to extract the global maximum power point (GMPP) in the cases of normal and partial shading conditions analyzed. The precise adjustment of the coefficients was made possible by visualizing the movement of the particles during the convergence process, while opposition-based learning (OBL) was used with FA to accelerate the convergence process by allowing the particle to move in the opposite direction. The proposed algorithm was simulated in the closest possible way to authentic operating conditions, and variable irradiance and partial shading conditions were implemented experimentally for a 60 [W] PV system. A two-stage PV grid-connected system was designed and deployed to validate the proposed algorithm. In addition, a comparison between the performance of the Perturbation and Observation (P&O) method and the proposed method was carried out to prove the effectiveness of this method over the conventional methods in tracking the GMPP.

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