scholarly journals Impact of Partial Shading on the P-V Characteristics and the Maximum Power of a Photovoltaic String

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1860 ◽  
Author(s):  
J. Teo ◽  
Rodney Tan ◽  
V. Mok ◽  
Vigna Ramachandaramurthy ◽  
ChiaKwang Tan

A photovoltaic system is highly susceptible to partial shading. Based on the functionality of a photovoltaic system that relies on solar irradiance to generate electrical power, it is tacitly assumed that the maximum power of a partially shaded photovoltaic system always decreases as the shading heaviness increases. However, the literature has reported that this might not be the case. The maximum power of a partially shaded photovoltaic system under a fixed configuration and partial shading pattern can be highly insusceptible to shading heaviness when a certain critical point is met. This paper presents an investigation of the impact of partial shading and the critical point that reduce the susceptibility of shading heaviness. Photovoltaic string formed by series-connected photovoltaic modules is used in this research. The investigation of the P-V characteristic curve under different numbers of shaded modules and shading heaviness suggests that the photovoltaic string becomes insusceptible to shading heaviness when the shaded modules irradiance reaches a certain critical point. The critical point can vary based on the number of the shaded modules. The formulated equation in this research contributes to determining the critical point for different photovoltaic string sizes and numbers of shaded modules in the photovoltaic string.

2021 ◽  
Vol 13 (19) ◽  
pp. 10575
Author(s):  
Amjad Ali ◽  
Kashif Irshad ◽  
Mohammad Farhan Khan ◽  
Md Moinul Hossain ◽  
Ibrahim N. A. Al-Duais ◽  
...  

Substantial progress in solar photovoltaic (SPV) dissemination in grid-connected and standalone power generation systems has been witnessed during the last two decades. However, weather intermittency has a non-linear characteristic impact on solar photovoltaic output, which can cause considerable loss in the system’s overall output. To overcome these inevitable losses and optimize the SPV output, maximum power point tracking (MPPT) is mounted in the middle of the power electronics converters and SPV to achieve the maximum output with better precision from the SPV system under intermittent weather conditions. As MPPT is considered an essential part of the SPV system, up to now, many researchers have developed numerous MPPT techniques, each with unique features. A Google Scholar survey from 2015–2021 was performed to scrutinize the number of published review papers in this area. An online search established that on different MPPT techniques, overall, 100 review articles were published; out of these 100, seven reviews on conventional MPPT techniques under shading or partial shading and only four under non-uniform solar irradiance are published. Unfortunately, no dedicated review article has explicitly focused on soft computing MPPT (SC-MPPT) techniques. Therefore, a comprehensive review of articles on SC-MPPT techniques is desirable, in which almost all the familiar SC-MPPT techniques have to be summarized in one piece. This review article concentrates explicitly on soft computing-based MPPT techniques under non-uniform irradiance conditions along with their operating principles, block/flow diagram. It will not only be helpful for academics and researchers to provide a future direction in SC-MPPT optimization research, but also help the field engineers to select the appropriate SC-MPPT for SPV according to system design and environmental conditions.


2021 ◽  
pp. 1-36
Author(s):  
Shahroz Anjum ◽  
Vivekananda Mukherjee ◽  
Gitanjali Mehta

Abstract This manuscript 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 work. 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 the other arrangements.


2018 ◽  
Vol 22 (1) ◽  
pp. 12
Author(s):  
K. Ramesh ◽  
R. Giri Ganesh ◽  
Sri Lakshmi Vineela Reddy ◽  
K. Mahalakshmi ◽  
S. Suganya

The energy obtained from the photovoltaic array is dependent on the available solar insolation, the panel tilt angle and the power point tracking algorithm of the system. Some of the Conventional MPPT methods are developed by considering uniform solar irradiance. During partial shading conditions, solar panel may produce multiple Local Maximum Power Points (LMPPs) in its power voltage characteristic curve. A new algorithm has been developed in this paper by using sequential sampling embedded with existing incremental conductance procedure in order to predict the Global Maximum Power Point (GMPP). The tracking capability of proposed algorithm is verified with simulation works carried out in MATLAB/SIMULINK. The results of proposed algorithm are likened with the results classical Perturb and Observe (P&O) and Incremental Conductance algorithms.


Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2421 ◽  
Author(s):  
Mariusz T. Sarniak ◽  
Jacek Wernik ◽  
Krzysztof J. Wołosz

Photovoltaics (PV) is the phenomenon of converting sun energy into electric energy by using photovoltaic cells. Furthermore, solar energy is the major renewable energy source. PV modules are systematically more efficient and manufacturing costs decrease at the same time. The PV module performance is affected by ambient temperature, humidity, wind speed, rainfall, incident solar radiation intensity and spectrum, dust deposition, pollution, and shading, which are environmental factors. The problem of partial shading of the generator often arises when designing photovoltaic installations. If it is not possible to avoid this phenomenon, its impact on the operation of the photovoltaic system should be estimated. The classical method is to measure the current–voltage characteristics, but it requires switching off the installation for the duration of the measurements. Therefore, this paper proposes a method using a computer simulation in the Matlab package with the implemented component “Solar Cell” for this purpose. Three cases of partial shading of photovoltaic modules with different degrees of shading were analyzed. The obtained results of the computer simulation were verified for two types of silicon PV modules: Mono- and polycrystalline.


Electronics ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 327 ◽  
Author(s):  
Muhammad Afzal Awan ◽  
Tahir Mahmood

Optimal energy extraction under partial shading conditions from a photovoltaic (PV) array is particularly challenging. Conventional techniques fail to achieve the global maximum power point (GMPP) under such conditions, while soft computing techniques have provided better results. The main contribution of this paper is to devise an algorithm to track the GMPP accurately and efficiently. For this purpose, a ten check (TC) algorithm was proposed. The effectiveness of this algorithm was tested with different shading patterns. Results were compared with the top conventional algorithm perturb and observe (P&O) and the best soft computing technique flower pollination algorithm (FPA). It was found that the proposed algorithm outperformed them. Analysis demonstrated that the devised algorithm achieved the GMPP efficiently and accurately as compared to the P&O and the FPA algorithms. Simulations were performed in MATLAB/Simulink.


Author(s):  
Norazlan Hashim ◽  
Zainal Salam ◽  
Dalina Johari ◽  
Nik Fasdi Nik Ismail

<span>The main components of a Stand-Alone Photovoltaic (SAPV) system consists of PV array, DC-DC converter, load and the maximum power point tracking (MPPT) control algorithm. MPPT algorithm was used for extracting maximum available power from PV module under a particular environmental condition by controlling the duty ratio of DC-DC converter. Based on maximum power transfer theorem, by changing the duty cycle, the load resistance as seen by the source is varied and matched with the internal resistance of PV module at maximum power point (MPP) so as to transfer the maximum power. Under sudden changes in solar irradiance, the selection of MPPT algorithm’s sampling time (T<sub>S_MPPT</sub>) is very much depends on two main components of the converter circuit namely; inductor and capacitor. As the value of these components increases, the settling time of the transient response for PV voltage and current will also increase linearly. Consequently, T<sub>S_MPPT </sub>needs to be increased for accurate MPPT and therefore reduce the tracking speed. This work presents a design considerations of DC-DC Boost Converter used in SAPV system for fast and accurate MPPT algorithm. The conventional Hill Climbing (HC) algorithm has been applied to track the MPP when subjected to sudden changes in solar irradiance. By selecting the optimum value of the converter circuit components, a fast and accurate MPPT especially during sudden changes in irradiance has been realized.</span>


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