scholarly journals Electrical Characteristics of PV Modules with Odd Strings by Arrangement on Bypass Diode

2017 ◽  
Vol 37 (4) ◽  
pp. 1-11
Author(s):  
Woo-Gyun Shin ◽  
Seok-Hwan Go ◽  
Young-Chul Ju ◽  
Hyung-Jun Song ◽  
Gi-Hwan Kang
Keyword(s):  
Electrical Characteristics ◽  
Bypass Diode ◽  
Pv Modules

scholarly journals Origin of Bypass Diode Fault in c-Si Photovoltaic Modules: Leakage Current under High Surrounding Temperature

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2416 ◽  
Author(s):  
Woo Shin ◽  
Suk Ko ◽  
Hyung Song ◽  
Young Ju ◽  
Hye Hwang ◽  
...  
Keyword(s):  
High Temperature ◽  
Leakage Current ◽  
Schottky Diode ◽  
Crystalline Silicon ◽  
Operating Voltage ◽  
Reverse Voltage ◽  
Photovoltaic Modules ◽  
Pv Module ◽  
Bypass Diode ◽  
Pv Modules

Bypass diodes have been widely utilized in crystalline silicon (c-Si) photovoltaic (PV) modules to maximize the output of a PV module array under partially shaded conditions. A Schottky diode is used as the bypass diode in c-Si PV modules due to its low operating voltage. In this work, we systematically investigated the origin of bypass diode faults in c-Si PV modules operated outdoors. The temperature of the inner junction box where the bypass diode is installed increases as the ambient temperature increases. Its temperature rises to over 70 °C on sunny days in summer. As the temperature of the junction box increases from 25 to 70 °C, the leakage current increases up to 35 times under a reverse voltage of 15 V. As a result of the high leakage current of the bypass diode at high temperature, melt down of the junction barrier between the metal and semiconductor has been observed in damaged diodes collected from abnormally functioning PV modules. Thus, it is believed that the constant leakage current applied to the junction caused the melting of the junction, thereby resulting in a failure of both the bypass diode and the c-Si PV module.

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 ◽  
...  
Keyword(s):  
Current Flow ◽  
Flow Analysis ◽  
Reverse Current ◽  
Open Circuit ◽  
Electrical Characteristics ◽  
Partial Shading ◽  
Pv Array ◽  
Pv Module ◽  
Parallel Circuits ◽  
Pv Modules

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.

scholarly journals A Comprehensive Review on Bypass Diode Application on Photovoltaic Modules

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2472 ◽  
Author(s):  
Romênia G. Vieira ◽  
Fábio M. U. de Araújo ◽  
Mahmoud Dhimish ◽  
Maria I. S. Guerra
Keyword(s):  
Power Systems ◽  
Extensive Experience ◽  
Ongoing Research ◽  
Comprehensive Review ◽  
Photovoltaic Modules ◽  
Bypass Diode ◽  
Pv Modules ◽  
Fast Development ◽  
Working Principle ◽  
Installed Capacity

Solar photovoltaic (PV) energy has shown significant expansion on the installed capacity over the last years. Most of its power systems are installed on rooftops, integrated into buildings. Considering the fast development of PV plants, it has becoming even more critical to understand the performance and reliability of such systems. One of the most common problems faced in PV plants occurs when solar cells receive non-uniform irradiance or partially shaded. The consequences of shading generally are prevented by bypass diodes. A significant number of studies and technical reports have been published as of today, based on extensive experience from research and field feedbacks. However, such material has not been cataloged or analyzed from a perspective of the technological evolution of bypass diodes devices. This paper presents a comprehensive review and highlights recent advances, ongoing research, and prospects, as reported in the literature, on bypass diode application on photovoltaic modules. First, it outlines the shading effect and hotspot problem on PV modules. Following, it explains bypass diodes’ working principle, as well as discusses how such devices can impact power output and PV modules’ reliability. Then, it gives a thorough review of recently published research, as well as the state of the art in the field. In conclusion, it makes a discussion on the overview and challenges to bypass diode as a mitigation technique.

scholarly journals Influence of Temperature on Electrical Characteristics of Different Photovoltaic Module Technologies

2018 ◽  
Vol 7 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Abdul Rehman Jatoi ◽  
Saleem Raza Samo ◽  
Abdul Qayoom Jakhrani
Keyword(s):  
Thin Film ◽  
Short Circuit ◽  
Open Circuit ◽  
Climatic Conditions ◽  
Photovoltaic Module ◽  
Electrical Characteristics ◽  
Influence Of Temperature ◽  
Average Maximum ◽  
Pv Modules ◽  
Influence Of Temperature On

­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­The aim of this study was to analyse the influence of temperature on electrical characteristics of crystalline and amorphous photovoltaic (PV) modules in outdoor conditions at Nawabshah. The experimental setup was made over the roof of the departmental building. The climatic conditions of site were recorded with the help of HP-2000 Professional Weather Station in three different timings of the day, i.e. morning, noon and evening. The electrical characteristics of the PV modules were recorded with Prova-210 and module temperatures with Prova-830. The maximum intensity of global solar radiation was recorded at noon and ambient temperature in the evening and the relative humidity in the morning hours. It was observed that amorphous module got 0.7°C, 1.0°C and 1.6°C more average temperature than polycrystalline, thin film and monocrystalline modules respectively. The average maximum measured open-circuit voltage was noted from amorphous with 96.7% and minimum from thin film with 81.3% of their respective values on standard conditions, whereas, the average maximum recorded short-circuit current was produced by thin film with 64.9% and minimum by amorphous with 51.4%. The average maximum power was produced by polycrystalline and minimum by amorphous module. It was discovered that the crystalline PV modules gave more fill factor than thin film and amorphous module.Article History: Received January 6th 2018; Received in revised form May 5th 2018; Accepted May 26th 2018; Available onlineHow to Cite This Article: Jatoi, A.R., Samo, S.R. and Jakhrani, A.Q. (2018). Influence of Temperature on Electrical Characteristics of Different Photovoltaic Module Technologies. Int. Journal of Renewable Energy Development, 7(2), 85-91.https://doi.org/10.14710/ijred.7.2.85-91

In situ TEM measurements of the electrical properties of interface dislocations

1992 ◽  
Vol 50 (2) ◽  
pp. 1338-1339
Author(s):  
F. M. Ross ◽  
R. Hull ◽  
D. Bahnck ◽  
J. C. Bean ◽  
L. J. Peticolas ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electronic Device ◽  
In Situ Tem ◽  
Device Performance ◽  
Misfit Dislocations ◽  
Electrical Characteristics ◽  
Strained Layer ◽  
Transmission Electron ◽  
Interfacial Dislocations

We describe an investigation of the electrical properties of interfacial dislocations in strained layer heterostructures. We have been measuring both the structural and electrical characteristics of strained layer p-n junction diodes simultaneously in a transmission electron microscope, enabling us to correlate changes in the electrical characteristics of a device with the formation of dislocations.The presence of dislocations within an electronic device is known to degrade the device performance. This degradation is of increasing significance in the design and processing of novel strained layer devices which may require layer thicknesses above the critical thickness (hc), where it is energetically favourable for the layers to relax by the formation of misfit dislocations at the strained interfaces. In order to quantify how device performance is affected when relaxation occurs we have therefore been investigating the electrical properties of dislocations at the p-n junction in Si/GeSi diodes.

The morphologies and electrical properties of indium contacts on (100) cadmium telluride surfaces

1992 ◽  
Vol 50 (2) ◽  
pp. 1422-1423
Author(s):  
A.M. Letsoalo ◽  
M.E. Lee ◽  
E.O. de Neijs
Keyword(s):  
Electrical Properties ◽  
Cadmium Telluride ◽  
Methanol Solution ◽  
Electrical Characteristics ◽  
Metal Contacts ◽  
Deposition Technique ◽  
Interfacial Layers ◽  
Semiconductor Contacts ◽  
Grown Single Crystal ◽  
Diamond Abrasive

Semiconductor devices require metal contacts for efficient collection of electrical charge. The physics of these metal/semiconductor contacts assumes perfect, abrupt and continuous interfaces between the layers. However, in practice these layers are neither continuous nor abrupt due to poor nucleation conditions and the formation of interfacial layers. The effects of layer thickness, deposition rate and substrate stoichiometry have been previously reported. In this work we will compare the effects of a single deposition technique and multiple depositions on the morphology of indium layers grown on (100) CdTe substrates. The electrical characteristics and specific resistivities of the indium contacts were measured, and their relationships with indium layer morphologies were established.Semi-insulating (100) CdTe samples were cut from Bridgman grown single crystal ingots. The surface of the as-cut slices were mechanically polished using 5μm, 3μm, 1μm and 0,25μm diamond abrasive respectively. This was followed by two minutes immersion in a 5% bromine-methanol solution.

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