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Impact of Subsystems on the Overall System Availability for the Large Scale Grid-connected Photovoltaic Systems
摘要： This paper demonstrates the impact of subsystem availability on a large scale grid-connected photovoltaic (PV) systems’ performance. Subsystem denotes to the installation of some subassemblies, which can be very small or gigantic in size, that serve this subsystem and the overall system. The analysis is largely based on a huge worldwide dataset of failures and repairs of various subassemblies, derived from different large scale grid-connected solar-PV systems. Major subsystems, such as a photovoltaic inverters (PVI), are also included, which are shown to have a signi?cant impact for improving on the overall system availability. An improved reliability block diagram (RBD) with an exponential probability distribution function is presented for estimating the reliability and availability performance of seven practical grid-connected solar-PV systems. In addition, availability importance measures are employed to rank various subsystems with regards to their impact on the overall system availability. Accordingly, it will be helping in identifying the subsystems that the planned maintenance should focus on in order to achieve the desired level of the availability. The secure operation of the system will be achieved by this approach. The implementation demonstrates the efficiency and the effectiveness of the proposed approach which may significantly contribute to enhancing the system availability.
关键词： reliability block diagram,failure rates,availability importance measures,repair rates,reliability,Photovoltaic systems,availability
更新于2025-09-12 10:27:22
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Material Property Changes in Defects Caused by Reverse Bias Exposure of CIGS Solar Cells
摘要： Partial shading of Cu(In,Ga)Se2 modules can lead to the formation of reverse bias induced wormlike defects. These wormlike defects act as local shunts and permanently decrease module output. A good understanding of the formation and propagation mechanisms of these defects is needed in order to mitigate the negative effects, or to prevent these defects from forming. In this article, wormlike defects were formed on small nonencapsulated cells by exposing them to reverse bias conditions. Scanning electron microscopy-energy-dispersive X-ray spectroscopy measurements showed a rearrangement of elements: Indium, gallium, and copper were replaced by cadmium, whereas selenium was replaced by sulfur in the area around the defect. Moreover, additional electronic-defect levels were found in that area with spectrally resolved photoluminescence spectroscopy. Based on the material changes in the area close to the wormlike defects, a propagation mechanism is proposed. The model assumes a chemical reaction as the driving force for propagation instead of melting because of ohmic heating.
关键词： photoluminescence (PL),photovoltaic (PV) cells,electric breakdown,reliability,thin film devices,Cadmium
更新于2025-09-12 10:27:22
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[IEEE 2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Udine, Italy (2019.9.4-2019.9.6)] 2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Impact of BEOL Design on Self-heating and Reliability in Highly-scaled FinFETs
摘要： This paper investigates the impact of BEOL design on device and backend reliability – HCI, BTI, EM – due to dependence of self-heating on BEOL in highly-scaled FinFETs. Our analysis indicates that due to poor thermal coupling to substrate – in the thin fin body devices – a large part of heat flows out of BEOL. This makes self-heating, and thus device (FEOL) temperature, very sensitive to BEOL design. The heat flow through BEOL also significantly increases the metal and via temperatures. The increased temperature negatively affects the overall reliability, and one of the ways to mitigate device degradation is optimization of BEOL design.
关键词： Self-heating effect,HCI,FinFET,Reliability,BTI,EM,Impact of BEOL design,Aging
更新于2025-09-12 10:27:22
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An Effective Method On Evaluating Photovoltaic Module Snail Trail
摘要： Although in recent years photovoltaic module snail trails have been extensively studied, when it comes to development of photovoltaic modules, it remains difficult to find the suitable method to evaluate what materials cause snail trails. The key is how to make the sample suitable for test so that it can generate snail trials. This paper intends to solve this problem and determine suitable test conditions to accelerate the occurrence of snail trails. An experimental comparison is also made to evaluate different test samples made with different combinations of materials.
关键词： snail trails,module reliability test,Snail trail,PV module defects
更新于2025-09-12 10:27:22
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Analysis of Field Degradation Rates Observed in All-India Survey of Photovoltaic Module Reliability 2018
摘要： The analysis of performance degradation in photovoltaic (PV) modules with c-Si technologies as observed in the All-India Survey of PV Module Reliability 2018 is presented in this article. The degradation rates are correlated with the module age, system size, mounting configuration, and climate of deployment. Key failure modes responsible for the higher degradation rates seen in certain sites are identified using visual, infrared, and electroluminescence imaging. Potential-induced degradation is found to be the key mechanism responsible for higher degradation rates seen in Young sites. Also, deployment in hot climates and rooftops is seen to accelerate degradation. Multipoint analysis of degradation rates is presented at sites inspected in prior All-India Surveys.
关键词： potential-induced degradation (PID),All-India Survey,solar photovoltaic (PV),light-induced degradation (LID),field survey,silicon,reliability,degradation
更新于2025-09-12 10:27:22
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Renewable Energy Accommodation Capability Evaluation of Power System with Wind Power and Photovoltaic Integration
摘要： This paper proposes a novel approach to evaluate the renewable energy accommodation capacity (REAC) of power system with wind power and photovoltaic (PV) integration. Based on Copula theory, the wind power output model is proposed considering uncertainty and the spatial correlation of wind speed in different wind farms. The PV output model is presented based on solar irradiance and weather influence factor. The solar irradiance depicts the periodicity and correlation of PV output while the new concept of weather influence factor is introduced to reflect the uncertainty of PV output. And the REAC evaluation model considering reliability of power system with wind power and PV integration is proposed with Monte-Carlo method. The proposed method comprehensively considers the characteristics of renewable energy and evaluates power system REAC more accurately. Furthermore, the influences of multiple factors on REAC of power system are analyzed. Results of case studies based on IEEE Case 39 test system and actual historical renewable energy data of northern China illustrate the feasibility of proposed approach.
关键词： Correlation,Reliability,Accommodation Capacity,Renewable Energy,Power System
更新于2025-09-12 10:27:22
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Microcharacterization of Interface Oxide Layer on Laser-Structured Silicon Surfaces of Plated Ni–Cu Solar Cells
摘要： Light-induced plating on laser-structured passivation layer openings is an alternative method to silver screen printing for fabrication of the front-side metal grid on silicon solar cells. Fundamental contact properties, such as adhesion and contact resistance, are determined at the highly inhomogeneous interface of laser-structured silicon and plated nickel. Usage of laser structuring and plating holds the risk that an interfacial oxide layer is incorporated to the contact stack. It is shown within this article that both native and laser-induced oxide formation influence contact properties. Although, a native oxide layer does not impede metal deposition during plating, the dynamics of the layer formation is shown to be changed. It is known that interface oxides harm the contact resistance, and it is reported that postplating annealing decreases the contact resistance. In this article, the microstructural basis of the temperature-induced changes is examined. By transmission electron microscopy and energy dispersive X-ray spectroscopy, no temperature-induced modification of the interface microstructure, such as silicide formation or metal-induced crystallization of the amorphous surface, is observed. Results suggest that the decrease is attributed to a temperature-induced change of the electrical properties of the interface oxide. Considering reports that partially closed interface oxide layers are an inherent feature of laser-structured plated contacts, the results presented motivate reconsidering the objective of postplating annealing. The results indicate that the beneficial impact of silicide formation is overrated for the case of laser-structured plated contacts, whereas the temperature-induced modifications on residual interface oxide layers are neglected in the scientific discussions on the given contact stack.
关键词： silicidation,semiconductor-metal interfaces,Photovoltaic cells,semiconductor device reliability
更新于2025-09-12 10:27:22
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Effect of Different Bonding Materials on Flip-Chip LED Filament Properties
摘要： This article researches the effect of Sn-based solder alloys on flip-chip light-emitting diode LED (FC-LED) filament properties. SEM images, shearing force, steady-state voltage, blue light luminous flux, and junction temperature were examined to demonstrate the difference between two types of FC-LED filaments welded with two solders. The microstructure surface of Sn90Sb10 filament solder joints was smoother and had fewer voids and cracks compared with that of SAC0307 filament solder joints, which indicates that the Sn90Sb10 filaments had a higher shearing force than the SAC0307 filaments; moreover, the average shearing force was beyond 200 gf (standard shearing force). The steady-state voltage and junction temperature of the Sn90Sb10 solder-welded FC-LED filament were lower, and the Sn90Sb10 filament had a relatively higher blue light luminous flux. If high reliability of the solder joints and better photoelectric properties of the filaments are required, this Sn90Sb10 solder is the best bonding material for FC-LED filament welding.
关键词： reliability,lead-free solder,photoelectric properties,FC-LED filament
更新于2025-09-12 10:27:22
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Use of indentation to study the degradation of photovoltaic backsheets
摘要： The ability of electrical insulating materials within a module to act as insulators is a key safety requirement for photovoltaic (PV) technology. Presently, however, the durability of backsheets may not be readily assessed. For example, the mechanical tensile test continues to be developed, and its use has not been validated such that a technically based pass/fail criteria may be established. This study examines the use of simple indentation methods, including durometer hardness and instrumented indentation, as a means to quantitively assess the degradation of PV backsheets. Characteristics including: hardness, modulus, load/displacement pro?le, creep hold response, and residual impression are explored in an empirical study. Glass/encapsulant/backsheet mini-modules constructed using backsheets including: polyamide (speci?cally the AAA backsheet product), poly (ethylene terephthalate) (PET), polyvinyl ?uoride (PVF) laminate (“TPE”), and polyvinylidene ?uoride (PVDF) were examined. An M-type durometer as well as Berkovich and cube-corner tips were used in the indentation experiments. Additional characterizations were performed to interpret the indentation measurements including: surface roughness measurements using atomic force microscopy (AFM), a chemical structure study using Fourier-transform infrared spectroscopy (FTIR), and phase-transition measurements using di?erential scanning calorimetry (DSC). The results are analyzed in the context of the combined accelerated stress test (C-AST) also explored in this study. Instrumented indentation (i.e., using a Berkovich tip) was able to distinguish between backsheets and quantify the e?ects of accelerated testing (including up to 60%, 25%, and 20% change in hardness, modulus, and creep displacement, respectively). The embrittlement of the backsheets was not readily assessable using cube-corner indentation. Cracking of the known-bad polyamide backsheet was observed from the C-AST, which was not observed to result from steady state UV weathering.
关键词： Reliability,Backsheet,Durability,Nanoindentation,Instrumented indentation
更新于2025-09-12 10:27:22
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AIP Conference Proceedings [AIP Publishing INTERNATIONAL SYMPOSIUM ON GREEN AND SUSTAINABLE TECHNOLOGY (ISGST2019) - Perak, Malaysia (23–26 April 2019)] INTERNATIONAL SYMPOSIUM ON GREEN AND SUSTAINABLE TECHNOLOGY (ISGST2019) - FEM simulation of deformations in strings of shingled solar cells subjected to mechanical reliability testing
摘要： Among several emerging interconnection technologies, shingled solar cell interconnection is the technology to realize highest power densities in solar modules. Its main feature is the replacement of ribbon stringing with direct interconnection by a slight overlapping of the solar cells using electrically conductive adhesives (ECA) as joint material. To succeed in a highly competitive market, this type of interconnection still has to prove its reliability, which requires a sound understanding of the loads this ECA joint faces during module lifetime. This study applies structural mechanic simulations based on the Finite Element Method (FEM) to investigate the impact of external loads according to IEC 61215 on a string of shingled solar cells within a solar module laminate. Linear elasticity is compared to the more realistic viscoelastic modelling of the encapsulant (EVA) and the ECA with the objective of reducing computational effort, which is caused by viscoelasticity. We found that linear elasticity can be applied in comparative studies to investigate the potential of different geometric designs to reduce mechanical stress in the joint. When it comes to the calculation of absolute values for stress and strain the strong viscoelastic properties of EVA and ECA cannot be neglected.
关键词： viscoelastic modelling,shingled solar cells,mechanical reliability testing,ECA joint,FEM simulation
更新于2025-09-12 10:27:22