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Photovoltaic Module Reliability || Development of Accelerated Stress Tests
摘要： The chapter discusses the development of accelerated stress tests (ASTs) for photovoltaic (PV) modules to identify and mitigate field failure modes. It outlines various ASTs such as Thermal Cycling, Damp Heat, Humidity Freeze, UV Light Exposure, Static Mechanical Load, Cyclic (Dynamic) Mechanical Load, Reverse Bias Hot Spot Test, Bypass Diode Thermal Test, and Hail Test, detailing their parameters and the failure modes they address. The importance of ASTs in improving module reliability and lifetime is emphasized, along with the challenges in accelerating certain processes without altering the failure mechanisms.
关键词： Reverse Bias Hot Spot Test,UV Light Exposure,Damp Heat,Static Mechanical Load,Hail Test,Thermal Cycling,Photovoltaic Module Reliability,Accelerated Stress Tests,Humidity Freeze,Bypass Diode Thermal Test,Cyclic (Dynamic) Mechanical Load
更新于2025-09-19 17:13:59
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[IEEE 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - Brasov, Romania (2019.11.3-2019.11.6)] 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - Influence of an Impulse Current near a Photovoltaic Solar Module on Bypass Diode Characteristics
摘要： Recently, failures in photovoltaic systems (PVSs) caused by lightning damage have been increasing. When lightning strikes a PVS, the bypass diode (BPD), which is a protection element in the solar cell module (PV-MDL), breaks down and burns out, rendering the PVS inoperable. In this study, an impulse current test was conducted to clarify the lightning-induced BPD failure mechanism. The impulse current with a peak of 100 kA was employed to simulate a lightning strike traveling in the vicinity of a PV-MDL. The results indicated that a BPD fails because lightning (induced electromotive force) strikes in the bypass circuit of the PV-MDL as the impulse current passes in its vicinity. Furthermore, installing a metal frame in the PV-MDL was shown to reduce the negative impact of such lightning strikes.
关键词： impulse current test,bypass diode,lightning,photovoltaic module,induced lightning
更新于2025-09-19 17:13:59
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Detailed modeling of large scale photovoltaic power plants under partial shading conditions
摘要： As the popularity of solar panels increases, significant research is being performed on maximizing the power extracted from photovoltaic systems. A phenomenon known as partial shading is a major source of power losses for photovoltaic plants. One way to reduce the effects of partial shading conditions is by using bypass–diodes. Typically any number of series and parallel–connected photovoltaic cells, known as photovoltaic cell arrays, are connected in anti–parallel with bypass–diodes. Due to this, it is advantageous to have an equivalent model for a photovoltaic cell array that is connected to bypass–diodes. In order to accurately develop this model, it is necessary to consider both series and parallel configurations of bypass–diodes, as well as the thermal behavior of bypass–diodes. The bypass–diode’s temperature model must be comprised of the constantly changing dissipated power, the effects of wind speed and the ambient temperature. This paper constructs an electro–thermal modular model for any size photovoltaic system and includes the effects of both the photovoltaic cells and bypass–diodes. A detailed analysis of the proposed model is performed and is then validated in both PSCAD/EMTDC and Matlab–Simscape. The proposed model is then further validated by the use of real measurements of ambient temperature, cell temperature, wind speed and then finally by a performance analysis of several maximum–power–point–tracking algorithms.
关键词： MPPT,Modeling,Bypass–diode,Photovoltaic,Partial shading
更新于2025-09-16 10:30:52
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Origin of Bypass Diode Fault in c-Si Photovoltaic Modules: Leakage Current under High Surrounding Temperature
摘要： 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.
关键词： diode junction melt,bypass diode of PV module,leakage current,temperature inside the junction box
更新于2025-09-12 10:27:22
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Impact of Bypass Diode Forward Voltage on Maximum Power of a Photovoltaic System under Partial Shading Conditions
摘要： The maximum power of a photovoltaic system can reduce significantly under partial shading conditions. Bypass diodes can be used in photovoltaic systems to bypass the shaded photovoltaic modules during partial shading. The bypass diode possesses a forward voltage that introduces a voltage drop in the photovoltaic system upon activation. Therefore, the maximum power of a photovoltaic system can reduce further during partial shading due to the forward voltage of the bypass diode. This paper presents an investigation into the effect of bypass diode forward voltage on the maximum power of a photovoltaic system under partial shading conditions. The results indicated that the forward voltage of the bypass diode did not necessarily decrease the maximum power of the photovoltaic system. This depends on whether the maximum power is delivered at a lower or higher voltage. When the maximum power is delivered at a higher voltage, it is insusceptible to the forward voltage. Conversely, when the maximum power is delivered at a lower voltage, it is susceptible to the forward voltage. In the worst-case scenario, the forward voltage of the bypass diode reduced the maximum power of the photovoltaic system by 16.48%, which was already subject to partial shading loss.
关键词： P-V characteristics,solar energy,Photovoltaic,bypass diode,partial shading
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America) - Gramado, Brazil (2019.9.15-2019.9.18)] 2019 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America) - An Adaptive Perturb and Observe Method with Clustering for Photovoltaic Module with Smart Bypass Diode under Partial Shading
摘要： The photovoltaic maximum power point tracking using perturb and observe method has a fixed step size, where a small step size has a slower time response and more accurate steady-state, while a large step size is the opposite. This work proposes an adaptive step size, proportional to the difference between actual and previous power sample, providing a fast time response and reducing the oscillations at steady-state. The oscillations are smaller with adaptive step size, but they are not annulled and the method presents loss by power oscillations. The clustering is used to eliminate this loss, setting the result of the simple average of the last five voltage samples. The enhanced method has been tested on a 72-cell photovoltaic module with a smart bypass diode per cell under partial shading. Modeling and simulation have been implemented using MATLAB/Simulink. The proposal obtained a faster time response and elimination of oscillations at steady-state.
关键词： Smart Bypass Diode,Adaptive Perturb and Observe with Clustering,Maximum Power Point Tracking,Photovoltaic Solar Module,Partial Shading
更新于2025-09-11 14:15:04