- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Harmonics assessment and mitigation in a photovoltaic integrated network
摘要： This paper presents a comprehensive review of harmonics dominance in PV integrated network. The findings of the review conducted for different scenarios are further supported by the results of an experimental case study exploring the dominance of harmonics in a real time PV integrated microgridunder varying solar irradiance condition. It is concluded that the level of Total Harmonic Distortions (THD) in the power system network varies in different scenarios. Some of the important scenarios are: (i) percentage of PV penetration in distribution network with respect to the types of connected load, (ii) location of PV integration, (iii) effect of harmonic resonance in power network, and (iv) varying power output of PV inverters with varying solar irradiance. A harmonic management system is finally proposed to limit the excessive harmonics in the network under different network conditions. The proposed harmonic management can be used to maintain the THD level within the standard limit and ensures the quality of energy supply to the communities.
关键词： Solar irradiance,Harmonic resonance,Photovoltaic (PV),Total harmonic distortion (THD),Microgrid (MG)
更新于2025-09-16 10:30:52
-
Soiling of Photovoltaic Modules: Comparing between Two Distinct Locations within the Framework of Developing the Photovoltaic Soiling Index (PVSI)
摘要： This article evaluates the impact of dust accumulation on the performance of photovoltaic (PV) modules in two different locations inside Egypt, Cairo and Beni-Suef. Two identical PV modules were used for that purpose, where each module was exposed to the outdoor environment in order to collect dust naturally for a period of three weeks, each in its corresponding location. The approximate dust density on each of the two PV modules was estimated. Moreover, the electrical performance was evaluated and compared under the same indoor testing conditions. The results show a better electrical performance and less dust density for the PV module located in Cairo compared to that located in Beni-Suef. The results further provide an indication for the impact of soling in different locations within the same country through a clear and simple procedure. In addition, it paves the way for establishing a Photovoltaic Soiling Index (PVSI) in terms of a Photovoltaic Dust Coefficient, as well as a Photovoltaic Dust Interactive Map. The product of such concepts could be used by the Photovoltaic systems designers everywhere in order to estimate the impact of dust on the future performance of PV modules in small and large installations in different regions around the globe, and during different times of the year as well.
关键词： photovoltaic dust coefficient,photovoltaic interactive dust map,photovoltaic soiling index (PVSI),dust accumulation,soiling,photovoltaic (PV)
更新于2025-09-12 10:27:22
-
Investigation of Rear-Emitter GaAs <sub/>0.75</sub> P <sub/>0.25</sub> Top Cells for Application to III–V/Si Tandem Photovoltaics
摘要： A rear-emitter (rear-junction) n-on-p+ device design was investigated for use in metamorphic monolithic III–V/Si tandem solar cells as an alternative to the traditional front-emitter (front-junction) n+-on-p design for potentially greater resistance to threading dislocation-induced performance degradation. A comparison of MOCVD-grown rear- versus front-emitter 1.7-eV bandgap GaAs0.75P0.25 top cell isotypes demonstrated as 30-mV advantage in WOC for the rear-emitter design. This reduction in WOC was determined to be nearly equally caused by a reduction in junction recombination current as well as reduced reverse saturation current from improved quasi-neutral region transport. These results suggest that the rear-emitter design may indeed be a promising pathway for application to metamorphic cells, including III–V/Si tandems, where achieving maximum voltage output is often hindered by elevated dislocation densities. However, further optimization of short-circuit current collection is needed to overcome suboptimal collection probability pro?les that could limit the ef?cacy of such structures.
关键词： semiconductor epitaxial layers,photovoltaic (PV),photovoltaic cells,III–V semiconductor materials
更新于2025-09-12 10:27:22
-
Thermomechanical Stress Distribution Analysis of Junction Box on Silicon Photovoltaic Modules Based on Finite Element Analysis
摘要： The electrical failure associated with concentration of heat and thermomechanical stress inside junction boxes is one of the main failure modes of photovoltaic (PV) modules. Three types of potting junction boxes with partial 72 Si cells PV panel are modeled under a constant current steady-state condition. The temperature distribution results are veri?ed through thermal dissipation tests. It is found that when one diode is in the ON-state, the split kind of junction box shows the highest temperature distribution on the surface, which is nearly 15 ?C higher than the other two types under 25 ?C with 11 A current applied. When three diodes are working, the other two types of junction box with three diodes inside will be intensely heated. The internal temperature distribution shows that bigger size and more copper coverage can help improve the thermal dissipation. Thermomechanical stress analysis based on the steady-state conditions is then carried out. The results show stress concentration on the side wall of the type I junction box while the other two types having conspicuous impact to the backsheet.
关键词： thermomechanical stress,temperature distribution,junction box,photovoltaic (PV),Finite element analysis
更新于2025-09-12 10:27:22
-
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
-
Photovoltaic Module Fault Detection Using Integrated Magnetic Sensors
摘要： Fault detection and diagnosis of photovoltaic (PV) modules have become vital for reliable, efficient, and safe PV operating systems. This article proposes a new inspection method which is based on measuring the magnetic flux density on the surface of crystalline silicon PV modules. To measure the magnetic flux density generated around busbars of PV modules, their surfaces are scanned by two types of small integrated magnetic sensors for the one-dimensional (1-D) and 2-D magnetic profiles. This method enable us to detect different types of faults in PV modules, perform on-site measurements, and real time diagnosis. Since the measurement devices are composed of simple and small sensors, the overall cost of this method is very low as compared to other conventional fault detection methods.
关键词： photovoltaic (PV) module,Fault detection,magnetic flux density,magnetic sensor
更新于2025-09-12 10:27:22
-
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
-
[IEEE 2019 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe) - Bucharest, Romania (2019.9.29-2019.10.2)] 2019 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe) - A New Transformerless Configuration for Grid-Connected Photovoltaic Inverters
摘要： Due to high efficiency, low cost and weight, inverters are widely used to deliver the transformerless photovoltaic (PV) energy to the grid. On the other hand, due to VDE standards, the leakage current between the stray capacitance of the PV array and the ground should be limited for the grid connected PV systems. In this case, some transformerless structures have been presented to restrict the leakage current. This paper presents a new transformerless structure for the PV inverters. The proposed structure keeps the common mode voltage constant in all switching periods and will suppress the leakage current. The performance of the proposed structure is verified by both mathematical and simulation (MATLAB/Simulink and PLECS Blockset) results.
关键词： Common mode (CM) voltage,Photovoltaic (PV),Leakage current,Transformerless inverter
更新于2025-09-12 10:27:22
-
[IEEE 2019 IEEE Energy Conversion Congress and Exposition (ECCE) - Baltimore, MD, USA (2019.9.29-2019.10.3)] 2019 IEEE Energy Conversion Congress and Exposition (ECCE) - Interharmonics Reduction in Photovoltaic Systems with Random Sampling MPPT Technique
摘要： An increasing penetration level of grid-connected Photovoltaic (PV) systems raises a concern regarding power quality problem, in particularly, interharmonics. According to previous research, the perturbation from the Maximum Power Point Tracking (MPPT) algorithm is one of the main root-cause of interharmonic emission in PV systems. In general, the interharmonic characteristics are strongly dependent on the sampling rate of the MPPT algorithm. A slow sampling rate of the MPPT algorithm can minimize the interharmonic emission but it results in poor tracking performance of the MPPT algorithm. Thus, there is a trade-off between the interharmonic emission and the MPPT efficiency when selecting the MPPT sampling rate. To overcome this problem, a new MPPT technique implemented with a random sampling rate is proposed in this paper. The proposed method randomly selects the MPPT algorithm sampling rate during each perturbation. This method is simple to be implemented but results in a significant reduction in the interharmonics of the output current and, at the same time, a high MPPT efficiency. The effectiveness of the proposed method has been validated experimentally with a single-phase grid-connected PV system. Moreover, the effect of interharmonic cancellation when implementing the proposed random sampling MPPT technique with parallel-connected PV inverters has also been demonstrated.
关键词： inverters,interharmonics,maximum power point tracking (MPPT),power quality,Photovoltaic (PV) systems
更新于2025-09-12 10:27:22
-
[IEEE 2019 20th International Symposium on Power Electronics (Ee) - Novi Sad, Serbia (2019.10.23-2019.10.26)] 2019 20th International Symposium on Power Electronics (Ee) - Simulation-Based Energy Assessment of PV Systems Installed in an Urban Environment
摘要： In this paper, a stochastic simulation procedure for energy assessment of PV systems is developed and tested. The method is especially adequate for urban applications since the impact of surrounding obstacles both for direct and diffuse irradiance is taken into account. The main input is the system location along with its monthly average irradiance and temperature statistics. Based on the input data, the program generates a set of random years represented by hourly sequences of global horizontal irradiance and ambient temperature. The generated sequences are then converted into the module plane-of-array irradiance and module temperature time series and, consequently, the AC energy production is estimated for each simulated year. The final results are presented in a form of probability density function of the system annual energy output.
关键词： Photovoltaic (PV),probabilistic analysis,obstacles,energy production estimation,urban environment
更新于2025-09-12 10:27:22