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- 2019
- photovoltaic power generation system
- sensitivity analysis
- Monte Carlo
- fuzzy layering evaluation method
- Electrical Engineering and Automation
- Xi’an Jiaotong University
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Analysis of power efficient compressor with fuzzy logic MPPT-based PV/FC system
摘要： In this paper, a hybrid photovoltaic (PV)/fuel cell (FC) power generation system is considered, where the hydrogen generated by the electrolysis process is used for subsequent FC operation. A novel induction motor-based compressor is proposed to boost up the pressure of hydrogen, and hence to improve the performance of the FC system. A fuzzy logic-based maximum power point tracking (MPPT) system is designed for the considered PV system. Finally, a coordinated control scheme is applied for controlling the power supplied to the load by integrating both the sources. The complete model is realised in the MATLAB/Simulink environment. Extensive simulation studies are conducted to verify the developed model. The performance of the complete system is found satisfactory under different conditions.
关键词： electrolyzer system,coordinated control,fuzzy logic-based MPPT,hydrogen generation,solar PV system
更新于2025-09-23 15:22:29
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Design of Short-Term Forecasting Model of Distributed Generation Power for Solar Power Generation
摘要： Background/Objectives: For efficient PhotoVoltaic (PV) power generation, computing and information technologies are increasingly used in irradiance forecasting and correction. Today the majority of PV modules are used for grid-connected power generation, so solar generation forecasting that predicts available PV output ahead is essential for integrating PV resources into electricity grids. This paper proposes a short-term solar power forecasting system that employs Neural Network (NN) models to forecast irradiance and PV power. Methods/Statistical Analysis: The proposed system uses the weather observations of a ground weather station, the medium-term weather forecasts of a physical model, and the short-term weather forecasts of the Weather Research and Forecasting (WRF) model as input. To increase prediction accuracy, the proposed system performs forecast corrections and determines the correction coefficients based on the characteristics and temperature of PV modules. The proposed system also analyzes the inclination angle of PV modules to predict PV power outputs. Results: In the correlation analysis of the forecasted and measured irradiance, R2 was over 0.85 for all look-ahead periods, indicating a high correlation between the two data. Conclusion/Application: In the future, the proposed forecasting system for solar power generation resources will be further refined and run in real environments.
关键词： Photovoltaic Power Forecasts,Wind Power,Forecasting System,Solar Energy,Distributed Power Generation
更新于2025-09-23 15:22:29
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A spatiotemporal probabilistic model-based temperature-augmented probabilistic load flow considering PV generations
摘要： The probabilistic steady‐state forecasting of a PV‐integrated power system requires a suitable forecasting model capable of accurately characterizing the uncertainties and correlations among multivariate inputs. The critical and foremost difficulties in the development of such a model include the accurate representation of the characterizing features such as complex nonstationary pattern, non‐Gaussianity, and spatial and temporal correlations. This paper aims at developing an improved high‐dimensional multivariate spatiotemporal model through enhanced preprocessing, transformation techniques, principal component analysis, and a suitable time series model that is capable of accurately modeling the trend in the variance of uncertain inputs. The proposed model is applied to the probabilistic load flow carried out on the modified Indian utility 62‐bus transmission system using temperature‐augmented system model for an operational planning study. A detailed discussion of various results has indicated the effectiveness of the proposed model in capturing the aforesaid characterizing features of uncertain inputs.
关键词： PV generation,probabilistic load flow,operational planning,spatiotemporal correlation,steady‐state forecasting
更新于2025-09-23 15:22:29
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Effects of nitrogen-dopant bonding states on liquid-flow-induced electricity generation of graphene: A comparative study
摘要： We fabricate, measure and compare the effects of the bonding states of dopant nitrogen atoms in graphene devices, specifically on the liquid-flow-induced electricity by these devices. We find that nitrogen doping enhances the voltage induced by liquid flow regardless of the nitrogen bonding state. However, different nitrogen bonding states affect graphene’s conductivity differently: while graphitic nitrogen is suitable for electricity-generation applications, pyridinic nitrogen is hopeless for this purpose, due to the formation of symmetry-breaking defects of the latter.
关键词： Water-graphene interface,Nitrogen doped graphene,Flow-induced electricity generation
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Portland, OR, USA (2018.9.23-2018.9.27)] 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Optimal Solar PV Sizing for Inverters Based on Specific Local Climate
摘要： Generally, the output power of the Photovoltaic (PV) panels is less than the nominal rating of the panel. On the other hand, the inverters of the PV systems are normally sized smaller than the nominal rating of the photovoltaic system. A typical PV to inverter power rating ratio is 1.2, which can be influenced by the weather condition. The main drawback is that during peak irradiance and optimal temperature situation, the peak power is generated at the PV, but the inverter is not sized for absorbing the whole power. This article develops a systematic method to calculate the optimal ratio between PV panel and inverter to absorb the maximum possible power with an optimal cost. This method uses the annual irradiance and temperature of the geographical region and extracts the power curves for a photovoltaic system in specific regions. Based on the distribution of the various weather conditions, the total possible power generation of the system is calculated. Then the possible extracted and lost power for different sizes of inverters are calculated to develop an efficiency function for the extracted power of the typical power system. This function is optimized considering the price of inverters and system. Both of conventional 1000 V PV system as well as recently developed 1500 V system for 480 VAC grid connection are studied and the effect of transformer in both case is investigated. The paper shows how 1500 V system is superior to its 1000 V counterpart.
关键词： optimal power rating,Grid connected solar generation,PV panel
更新于2025-09-23 15:22:29
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A Highly Birefringent and Nonlinear AsSe<formula><tex>$_{2}$</tex></formula>-As<formula><tex>$_{2}$</tex></formula>S<formula><tex>$_{5}$</tex></formula> Photonic Crystal Fiber with Two Zero-Dispersion Wavelengths
摘要： A hybrid AsSe2–As2S5 photonic crystal ?ber (PCF) with a solid elliptical core is proposed and studied theoretically by the full-vector ?nite element method. The core and cladding of the PCF are made of AsSe2 and As2S5 glasses, respectively. Simulation results demonstrates that, at the operating wavelength of 1.55 μm, the proposed PCF not only exhibits a very high birefringence of 0.091 but also has large nonlinear coef?cients of 147.8 and 78.2 W ?1m ?1 for the X- and Y-polarized (X and Y-pol) modes, respectively. Moreover, it is able to achieve two zero-dispersion wavelengths for both the X-pol (1.52 and 2.19 μm) and Y-pol (1.43 and 2.12 μm) modes. The proposed hybrid PCF exhibits excellent polarization maintaining and the nonlinearity performance, thus, suitable to be used in supercontinuum spectrum generation and polarization maintaining nonlinear signal processing.
关键词： zero-dispersion wavelength,High birefringence,supercontinuum spectrum generation,photonic crystal ?ber,nonlinearity
更新于2025-09-23 15:22:29
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Flexible TiO2-coated nanocellulose membranes incorporated with CdTe as electrodes in photoelectrochemical cells
摘要： Incorporation of quantum dots (QDs) into porous matrices has triggered the development of novel optical devices. In this work, TiO2 sensitized by CdTe incorporated into bacterial nanocellulose (BNC) membranes were tested as photoelectrodes in a photoelectrochemical cell directed to the water splitting for hydrogen generation. The flexible membranes were produced by immersing BNC membranes in an aqueous solution of CdTe capped with glutathione (CdTe–GSH) and further deposited over a thin layer of TiO2. Incorporation of CdTe–GSH into BNC membranes was confirmed by infrared spectroscopy. Fluorescence spectroscopy revealed that the luminescence intensity increased with the immersion time in the CdTe–GSH solution. Field-emission gun scanning electron microscopy (FEG-SEM) images revealed that the CdTe/QDs (5 nm) were homogeneously dispersed on the cellulose nanofibers. BNC/CdTe–GSH membranes was tested as photoelectrodes. Photoelectrochemical cells exhibited a significant photocurrent in wavelengths ranging from 400 to 800 nm, which indicates their potential for applications as flexible electrodes, sensors and photovoltaic systems.
关键词： Photoelectrochemical cell,Quantum dots,Bacterial nanocellulose,Water splitting,Hydrogen generation
更新于2025-09-23 15:21:21
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Sky Image-Based Solar Irradiance Prediction Methodologies Using Artificial Neural Networks
摘要： In order to decelerate global warming, it is important to promote renewable energy technologies. Solar energy, which is one of the most promising renewable energy sources, can be converted into electricity by using photovoltaic power generation systems. Whether the photovoltaic power generation systems are connected to an electrical grid or not, predicting near-future global solar radiation is useful to balance electricity supply and demand. In this work, two methodologies utilizing artificial neural networks (ANNs) to predict global horizontal irradiance in 1 to 5 minutes in advance from sky images are proposed. These methodologies do not require cloud detection techniques. Sky photo image data have been used to detect the clouds in the existing techniques, while color information at limited number of sampling points in the images are used in the proposed methodologies. The proposed methodologies are able to capture the trends of fluctuating solar irradiance with minor discrepancies. The minimum root mean square errors of 143 W/m2, which are comparable with the existing prediction techniques, are achieved for both of the methodologies. At the same time, the proposed methodologies require much less image data to be handled compared to the existing techniques.
关键词： Artificial Neural Network,Photovoltaic Power Generation,Solar Energy,Global Horizontal Irradiance Prediction,Sky Image
更新于2025-09-23 15:21:21
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Evaluation method for the performance of light screen array measurement system based on semi-physical simulation
摘要： The paper presents a method to evaluate the performance of light screen array measurement system (LSA for short) objectively and scienti?cally. We put forward the scheme of semi-physical veri?cation platform based on arbitrary waveform generator (AWG), and this instrument is used as a substitute for light screen detector in the LSA. according to some main characteristics of dynamic signal, the waveform ?les of two simulation signals with a certain time interval are compiled and created through con?guring some options through a signal waveform edition software. Furthermore, these waveform ?les are downloaded into the AWG to generate two channel simulation signals. Then, the time interval of these two signals can be measured in the signal acquisition & processing module of LSA. Finally, we can compare the di?erence between true values and measured results. Through experiment and analysis, the proposed method can meet the requirement of performance evaluation on the LSA, and it is superior to the other previous methods.
关键词： Semi-physical simulation,Noise environment,Waveform modeling and editing,Photoelectric measurement,Dynamic signal generation
更新于2025-09-23 15:21:21
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Ultrafast X-ray Transient Absorption Spectroscopy of Gas-Phase Photochemical Reactions: A New Universal Probe of Photoinduced Molecular Dynamics
摘要： Time-resolved spectroscopic investigations of light-induced chemical reactions with universal detection capitalize recently on single-photon molecular probing using laser pulses in the extreme ultraviolet or X-ray regimes. Direct and simultaneous mappings of the time-evolving populations of ground-state reactants, Franck?Condon (FC) and transition state regions, excited-state intermediates and conical intersections (CI), and photoproducts in photochemical reactions utilize probe pulses that are broadband and energy-tunable. The limits on temporal resolution are set by the transit- or dwell-time of the photoexcited molecules at specific locations on the potential energy surface, typically ranging from a few femtoseconds to several hundred picoseconds. Femtosecond high-harmonic generation (HHG) meets the stringent demands for a universal spectroscopic probe of large regions of the intramolecular phase-space in unimolecular photochemical reactions. Extreme-ultraviolet and soft X-ray pulses generated in this manner with few-femtosecond or sub-femtosecond durations have enormous bandwidths, allowing the probing of many elements simultaneously through excitation or ionization of core?electrons, creating molecular movies that shed light on entire photochemical pathways. At free electron lasers (FELs), powerful investigations are also possible, recognizing their higher flux and tunability but more limited bandwidths. Femtosecond time-resolved X-ray transient absorption spectroscopy, in particular, is a valuable universal probe of reaction pathways that maps changes via the fingerprint core-to-valence resonances. The particular power of this method over valence-ionization probes lies in its unmatched element and chemical-site specificities. The elements carbon, nitrogen, and oxygen constitute the fundamental building blocks of life; photochemical reactions involving these elements are ubiquitous, diverse, and manifold. However, table-top HHG sources in the “water-window” region (280?550 eV), which encompasses the 1s-absorption edges of carbon (284 eV), nitrogen (410 eV), and oxygen (543 eV), are far from abundant or trivial. Recent breakthroughs in the laboratory have embraced this region by using long driving-wavelength optical parametric amplifiers coupled with differentially pumped high-pressure gas source cells. This has opened avenues to study a host of photochemical reactions in organic molecules using femtosecond time-resolved transient absorption at the carbon K-edge. In this Account, we summarize recent efforts to deploy a table-top carbon K-edge source to obtain crucial chemical insights into ultrafast, ultraviolet-induced chemical reactions involving ring-opening, nonadiabatic excited-state relaxation, bond dissociation and radical formation. The X-ray probe provides a direct spectroscopic viewport into the electronic characters and configurations of the valence electronic states through spectroscopic core-level transitions into the frontier molecular orbitals of the photoexcited molecules, laying fertile ground for the real-time mapping of the evolving valence electronic structure. The profound detail and mechanistic insights emerging from the pioneering experiments at the carbon K-edge are outlined here. Comparisons of the experimental methodology with other techniques employed to study similar reactions are drawn, where applicable and relevant. We show that femtosecond time-resolved X-ray transient absorption spectroscopy blazes a new trail in the study of nonadiabatic molecular dynamics. Despite table-top implementations being largely in their infancy, future chemical applications of the technique will set the stage for widely applicable, universal probes of photoinduced molecular dynamics with unprecedented temporal resolution.
关键词： time-resolved spectroscopy,photochemical reactions,high-harmonic generation,X-ray transient absorption spectroscopy,nonadiabatic molecular dynamics
更新于2025-09-23 15:21:21