- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 North American Power Symposium (NAPS) - Wichita, KS, USA (2019.10.13-2019.10.15)] 2019 North American Power Symposium (NAPS) - Study of Smart Grid Protection Challenges with High Photovoltaic Penetration
摘要： We present an automatic parameter setting method to achieve an accurate second-order Kalman ?lter tracker based on a steady-state performance index. First, we propose an ef?cient steady-state performance index that corresponds to the root-mean-square (rms) prediction error in tracking. We then derive an analytical relationship between the proposed performance index and the generalized error covariance matrix of the process noise, for which the automatic determination using the derived relationship is presented. The model calculated by the proposed method achieves better accuracy than the conventional empirical model of process noise. Numerical analysis and simulations demonstrate the effectiveness of the proposed method for targets with accelerating motion. The rms prediction error of the tracker designed by the proposed method is 63.8% of that with the conventional empirically selected model for a target accelerating at 10 m/s2.
关键词： steady-state performance,Tracking ?lter,process noise,Kalman ?lter,parameter setting
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Performance Degradation in aSi/cSi Heterojunction Solar Cells by Glassy Dynamics
摘要： We present an automatic parameter setting method to achieve an accurate second-order Kalman ?lter tracker based on a steady-state performance index. First, we propose an ef?cient steady-state performance index that corresponds to the root-mean-square (rms) prediction error in tracking. We then derive an analytical relationship between the proposed performance index and the generalized error covariance matrix of the process noise, for which the automatic determination using the derived relationship is presented. The model calculated by the proposed method achieves better accuracy than the conventional empirical model of process noise. Numerical analysis and simulations demonstrate the effectiveness of the proposed method for targets with accelerating motion. The rms prediction error of the tracker designed by the proposed method is 63.8% of that with the conventional empirically selected model for a target accelerating at 10 m/s2.
关键词： steady-state performance,Tracking ?lter,process noise.,Kalman ?lter,parameter setting
更新于2025-09-23 15:19:57
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Densification of pure copper by selective laser melting process
摘要： Pure copper is utilized as a material for products with complicated shape and high thermal conductivity such as heat exchangers. However, it is difficult to fabricate pure copper parts with high density by the selective laser melting (SLM) process. One of the reasons is considered to be its high thermal conductivity by which the heat in the melt pool rapidly diffuses away. Additionally, the lower rate of energy absorption of fiber laser power for pure copper makes the size of melt pool smaller. In this research, the optimum fabrication condition of high-purity 99.9% copper fabricated by SLM process was investigated by evaluating the density and microstructure. As a result, it was found that the optimum condition of laser power and scan speed are 800~900W and 300 mm/s, respectively, and the optimum energy density is around 1000 J/mm3, which is much higher than that of other materials due to high reflectivity and high thermal conductivity of pure copper. And also, it was found that the hatch pitch is important factor to achieve the densification of the as-built specimen and the optimum hatch pitch was 0.01 mm. The high density parts were successfully fabricated by the optimum fabrication condition. The maximum density of the as-built specimen was 96.6 % and was much higher than that of the as-built part already reported.
关键词： Microstructure,Copper,Density,Process parameter,Additive manufacturing
更新于2025-09-23 15:19:57
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Role of magnetic field on self focusing of super-Gaussian laser beam under relativistic effect
摘要： Considering an external magnetic field along the direction of propagation of laser, the self focusing of a super-Gaussian laser beam is studied when it propagates through the plasma at relativistic intensities. We consider the cyclotron motion of the electrons and use the tensor form of the plasma dielectric constant obtained based on the direction of the external magnetic field. For completeness, relativistic mass effect is incorporated in both the plasma frequency and electron cyclotron frequency. Using appropriate conditions, an equation for the beam width parameter is derived and solved. The equilibrium beam radius for a self trapped laser beam is also derived. Self focusing is better when cyclotron effects are taken into account. At higher intensity and higher spot size of the laser beam, self focusing becomes better.
关键词： Super-Gaussian laser,Moment theory,Beam width parameter,Self focusing,Relativistic nonlinearity
更新于2025-09-23 15:19:57
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Determination of the series resistance of a solar cell through its maximum power point
摘要： A simple analytical approach has been developed to determine the series resistance, Rs, of a solar cell. The method adopted here depends only on the knowledge of the open-circuit voltage, Voc, and the current and voltage at the maximum power point, Isc and Vmp respectively. This approach, based on a knowledge of these operating output parameters of the cell, provides a theoretical framework for an existing computer simulated approach which has been widely used in industries.
关键词： series resistance,short-circuit current,five-parameter model,light generated current,solar cell,shunt resistance
更新于2025-09-23 15:19:57
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An improved wind driven optimization algorithm for parameters identification of a triple-diode photovoltaic cell model
摘要： The double-diode photovoltaic cell model is insufficient to accurately characterize the different current components of a photovoltaic cell. Therefore, the triple-diode model of a photovoltaic cell is considered to model its complicated physical characteristics by clearly defining the different current components of the photovoltaic cell. The identification of its unknown parameters is a complex, multi-modal and multi-variable optimization problem. An improved wind driven optimization algorithm is proposed in this paper to identify its nine unknown parameters. The proposed method is a combination of the mutation strategy of the differential evolution algorithm and the covariance matrix adaptation evolution strategy of the wind driven optimization algorithm. The mutation strategy aims to bolster the exploration ability of the improved wind driven optimization algorithm, while the covariance matrix adaptation evolution strategy based on wind driven optimization algorithm aims to improve the searching of the classical wind driven optimization algorithm. Therefore, improved wind driven optimization algorithm is more accurate and faster than the classical wind driven optimization algorithm in finding the global optimum and balancing exploration and exploitation. The proposed model has been utilized on 15-minute interval data to identify the unknown parameters of three commercial photovoltaic technologies, namely, mono-crystalline, poly-crystalline and thin-film. To show the effectiveness of the proposed model, its performance is validated by comparing it with that obtained by the classical wind driven optimization, the adaptive wind driven optimization, moth-flame optimizer, sunflower optimization and the improved opposition-based whale optimization algorithms. The results demonstrate that improved wind driven optimization outperforms the aforementioned models in accuracy, convergence speed and feasibility. In addition, improved wind driven optimization more clearly defined different current components and generated any current-voltage curve under any operating condition.
关键词： I-V characteristic curve,IWDO algorithm,Parameter identification,Photovoltaic,Triple-diode model
更新于2025-09-23 15:19:57
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Comparative study of defect mode intensity and wavelength modulation in Bragg fiber waveguide sensors
摘要： Sensing parameters of Bragg ?ber waveguides having a defect layer in the cladding region are studied theoretically for bio-sensing and thickness monitoring applications. A comparison between Bragg ?ber waveguides consist of a liquid-core surrounded with alternate high refractive index (R.I.) contrast of claddings and low R.I. contrast of claddings is presented. In non-homogeneous multilayer cylindrical system, the transmittance of proposed waveguide-based sensors is formulated using transfer matrix method and Hankel formalism. Both considered structures show photonic bandgap with a narrow passband in the bandgap region. This narrow passband is treated as sensing signal because its position and intensity depends on the diameter and refractive index of core material. The high refractive index contrast cladding waveguide shows larger intensity shift than low refractive index contrast cladding waveguide. The presence of defect layer in both considered waveguides is able to increase the sensing parameters like detection accuracy and overall performance.
关键词： Quality parameter,Liquid core Bragg ?ber waveguide,Defect mode,Detection accuracy,Sensitivity
更新于2025-09-23 15:19:57
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Extraction of uncertain parameters of single-diode model of a photovoltaic panel using simulated annealing optimization
摘要： In this article, our goal is to improve the estimation of the parameters of solar photovoltaic models, we propose a method based on Simulated Annealing (SA) Optimization, the proposed algorithm takes into account the uncertainties of measurements. This algorithm consists of three steps such as the extraction of the parameters in a conventional manner, then the determination of the uncertainties of each parameter, finally the determination of the instantaneous parameters taking into account the results of the first two steps. For the validation of the proposed theoretical developments, the algorithm is applied to four different PV parameter estimation problems. The results obtained are compared with well-established algorithms to confirm its effectiveness. These comparisons have shown that the proposed method exhibits largely effective performances than existing methods in the literature.
关键词： Uncertainties measurements,Photovoltaic model,Simulated annealing optimization,Parameter estimation
更新于2025-09-23 15:19:57
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Influence of solvent solubility parameter on the power law exponents and critical concentrations of one soluble polyimide in solution
摘要： Solvent species influence the interactions of dissolved polymers in solution and consequently induce changes in solution properties. A soluble polyimide was synthesized through polycondensation, and four solvents, namely, N,N-dimethylacetamide (DMAc), N-methyl pyrrolidone (NMP), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO), were selected to investigate systematically the influence of solubility parameter on solution power law behaviors. The power law relationship between specific viscosity and concentration was established using rheology and applying concepts from the Zimm, Rouse-Zimm, and Doi-Edwards models. All power law exponents were higher than theoretical predictions, and in the three concentration regions, i.e. dilute, semidilute unentangled, and semidilute entangled, the exponents increase, decrease, and increase, respectively, with respect to solubility parameter. Arguments derived from the listed models are proposed to explain these trends. The influences of solubility parameter on the overlap and entanglement concentrations are also discussed.
关键词： Solubility parameter,Critical concentration,Polyimide,Power law exponent,Solution property
更新于2025-09-19 17:15:36
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Qubit-channel metrology with very noisy initial states
摘要： We consider an arbitrary qubit channel depending on a single parameter, which is to be estimated by a physical process. Using the quantum Fisher information per channel invocation to quantify the estimation accuracy, we consider various estimation protocols when the available initial states are mixed with very low purity r. We compare a protocol using a single channel invocation on one out of n qubits prepared in a particular correlated input state to the optimal protocol using uncorrelated input states, with the same initial-state purity. We show that, to lowest order in initial-state purity, for a unital channel this correlated-state protocol enhances the estimation accuracy by a factor between n ? 1 and n, provided that nr 2 (cid:2) 1. We also show that to lowest order in initial-state purity, a broad class of nonunital channels yields no gain regardless of the input state.
关键词： unital channel,qubit channel,nonunital channel,noisy initial states,quantum parameter estimation,quantum Fisher information
更新于2025-09-19 17:15:36