scholarly journals Reversible Efficiency Variation of Tandem Amorphous/Microcrystalline Si Photovoltaic Modules in Outdoor Operation

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2876
Author(s):  
Fabio Ricco Galluzzo ◽  
Cosimo Gerardi ◽  
Andrea Canino ◽  
Salvatore Lombardo
Keyword(s):  
Experimental Studies ◽  
Solar Spectrum ◽  
Clear Correlation ◽  
Photovoltaic Modules ◽  
Performance Improvements ◽  
Defect Annealing ◽  
Power Point ◽  
Lower Temperature ◽  
Staebler Wronski Effect ◽  
Silicon Based

The Staebler-Wronski effect in amorphous silicon based photovoltaic devices is responsible for degradation of their power conversion efficiency, within approximately the first one thousand hours of light soaking. Several experimental studies led to highlight the performance instability phenomena for the mentioned devices, underling that recovery and improvement of such performance are observable, by subjecting such devices (both of single-junction and tandem types) to DC reverse bias stresses under illumination, or to operation in the Maximum Power Point (MPP) under variable conditions of temperature and illumination. In this work, we present and discuss the results of novel recent outdoor tests on stabilized specimens (i.e., exposed to 1000 h extended light soaking, before our tests) of tandem amorphous/microcrystalline Si (a-Si/µc-Si) photovoltaic (PV) minimodules operating in their MPP, by analyzing the causes of the performance instability effects, systematically observed on a daily scale. During the mentioned tests, we have monitored the solar cell operating temperature and the incident solar spectrum at various times in different days to verify the effect of cell temperature and solar spectrum changes on the cell performances. The experimental results show a clear correlation between performance improvements of the photovoltaic modules and their thermal history during the outdoor tests, proving the interplay between defect build-up at a lower temperature and defect annealing at a higher temperature, taking place in the solar cells operated in MPP during conventional outdoor operation.

Evaluation of the impact of solar spectrum and temperature variations on output power of silicon-based photovoltaic modules

2006 ◽  
Vol 90 (20) ◽  
pp. 3568-3575 ◽  
Author(s):  
Shingo Nagae ◽  
Masanori Toda ◽  
Takashi Minemoto ◽  
Hideyuki Takakura ◽  
Yoshihiro Hamakawa
Keyword(s):  
Output Power ◽  
Solar Spectrum ◽  
Temperature Variations ◽  
Photovoltaic Modules ◽  
Silicon Based ◽  
The Impact

Ten years outdoor operation of silicon based photovoltaic modules at central latitude of Japan

2014 ◽  
Vol 65 ◽  
pp. 78-82 ◽  
Author(s):  
Aika Kamei ◽  
Shota Yoshida ◽  
Hideyuki Takakura ◽  
Takashi Minemoto
Keyword(s):  
Photovoltaic Modules ◽  
Silicon Based

Modified Distribution Transformer for Enhancing Power Quality in Distribution Systems

2016 ◽  
Vol 7 (4) ◽  
pp. 1386
Author(s):  
Preetha P.K. ◽  
P.S. Chandramohanan Nair
Keyword(s):  
Power Distribution ◽  
Distribution Systems ◽  
Experimental Studies ◽  
Considerable Improvement ◽  
Distribution Transformer ◽  
Maximum Power Point ◽  
Non Linear ◽  
Power Point ◽  
Day By Day ◽  
Harmonic Power

<p>The percentage of non-linear loads in the power distribution sector is increasing day by day. Harmonics injected by these non-linear loads circulate in the delta windings of the conventional distribution transformer thereby increasing the temperature and losses. This reduces the efficiency and life of the transformers. In a modified distribution transformer configuration proposed recently, called star-star-delta_utilized configuration (YYD_utilized), the harmonics circulating in the delta winding was utilized and the drainage power thus recovered was used to power auxiliary loads. This paper presents the experimental studies conducted on YYD_utilized distribution transformer. When compared to conventional star-star, delta-star and star-star-delta transformers, the new configuration of YYD_utilized transformer has shown considerable improvement in transformer efficiency.  The results obtained show that when the power from the circulating harmonics is recovered and utilized, it not only improves transformer efficiency but also improves the power factor and reduces the harmonic distortions at the primary side of the transformer. The results obtained also suggest the existence of maximum power point or an optimum loading for the recovered harmonic power.</p>

Maximum Power Point Tracker Using Fuzzy Logic Controller with Reduced Rules

2018 ◽  
Vol 9 (3) ◽  
pp. 1381
Author(s):  
Adel Haddouche ◽  
Mohammed Kara ◽  
Lotfi Farah
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Good Alternative ◽  
Maximum Power ◽  
Photovoltaic System ◽  
Maximum Power Point ◽  
Practical Applications ◽  
Performance Improvements ◽  
Point Tracking ◽  
Power Point

<p><span lang="EN-US">This paper presents a fuzzy logic controller for maximum power point tracking (MPPT) in photovoltaic system with reduced number of rules instead of conventional 25 rules to make the system lighter which will improve the tracking speed and reduce the static error, engendering a global performance improvements. in this work the proposed system use the power variation and current variation as inputs to simplify the calculation, the introduced controller is connected to a conventional grid and simulated with MATLAB/SIMULINK. The simulation results shows a promising indication to adopt the introduced controller as an a good alternative  to traditional MPPT system for further practical applications</span></p>

scholarly journals Temperature based maximum power point tracking for photovoltaic modules

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Josean Ramos-Hernanz ◽  
Irantzu Uriarte ◽  
Jose Manuel Lopez-Guede ◽  
Unai Fernandez-Gamiz ◽  
Amaia Mesanza ◽  
...  
Keyword(s):  
Maximum Power Point Tracking ◽  
Maximum Power ◽  
Maximum Power Point ◽  
Photovoltaic Modules ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Power Point

scholarly journals Modelling ion populations in astrophysical plasmas: carbon in the solar transition region

2019 ◽  
Vol 626 ◽  
pp. A123 ◽  
Author(s):  
R. P. Dufresne ◽  
G. Del Zanna
Keyword(s):  
Transition Region ◽  
Experimental Studies ◽  
Charge State Distribution ◽  
Dielectronic Recombination ◽  
Stellar Atmospheres ◽  
Astrophysical Plasmas ◽  
Atomic Process ◽  
Solar Transition Region ◽  
Solar Transition ◽  
Lower Temperature

The aim of this work is to improve the modelling of ion populations in higher density, lower temperature astrophysical plasmas, of the type commonly found in lower solar and stellar atmospheres. Ion population models for these regions frequently employ the coronal approximation, which assumes conditions more suitable to the upper solar atmosphere, where high temperatures and lower densities prevail. The assumed conditions include all ions being in the ground state and steady-state equilibrium, where there is sufficient time for ionisation and recombination to take place. Using the coronal approximation for modelling the solar transition region gives theoretical lines intensities for the Li-like and Na-like isoelectronic sequences which are often factors of two to five times lower than observed. The works of Burgess & Summers (1969, ApJ, 157, 1007) and Nussbaumer & Storey (1975, A&A, 44, 321) show the important part ions in excited levels play when included in the modelling. As density increases metastable levels become populated and ionisation rates increase, whereas dielectronic recombination through highly excited levels is suppressed. Photo-ionisation is also shown by Nussbaumer & Storey to have an effect on the charge-state distribution of carbon in these regions. Their models, however, use approximations for the atomic rates to determine the ion balance. Presented here is the first stage in updating these earlier models of carbon by using rates from up-to-date atomic calculations and more recent photo-ionising radiances. Where atomic rates were not readily available, in the case of electron impact direct ionisation and excitation–auto-ionisation, new calculations were made using the Flexible Atomic Code and Autostructure, and compared to theoretical and experimental studies. The effects each atomic process has on the ion populations as density changes is illustrated, and final results from the modelling are compared to the earlier works. Lastly, the new results for ion populations were used to predict line intensities for the solar transition region in the quiet Sun. In comparison to coronal approximation modelling the new results show significantly improved agreement with observations.

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