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Autonomous Load Sharing Technique in Solar Photovoltaic System Based DC Microgrid
摘要： In this article, efforts have been made to study, analyze and implement the autonomous current sharing technique by using two parallel connected Solar Photovoltaic (SPV) systems with maximum power point tracking controller (MPPT) considering cable resistances. It mainly formulates a procedure to minimize the current sharing mismatch across load by controlling the duty cycle of MPPT controller. Also, an analysis of various factors affecting (SPV) characteristics has been reported. Further, the system has been analyzed with two interconnected SPV systems to a common load, and an accurate load sharing phenomenon has been achieved by using adaptive gain tuning technique. The proposed scheme has been verified by conducting the experiments, and its results have been explored for various irradiation and load conditions. Experimental results reveal that at all conditions current from the sources are equally shared to loads and adequate rest is delivered to energy storage systems.
关键词： Adaptive gain tuning algorithm,Load sharing techniques,Solar Photovoltaic systems
更新于2025-09-12 10:27:22
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FA-LAR: an efficient flow aware based load adaptive routing scheme for optical communication networks
摘要： Routing Protocols have been proposed to enable the network to identify and suggest various routes to number of demanded flows. In the Flow-Aware Network Models, the routes are identified and selected with the help of Flow Tables or Flow Identifiers that proposed by Flow Aggregation Mechanism. That is, users can define a Flow Aggregation Model to suggest routes depend on their defined-demanded flows and this model effectively handles many flows, which helps core routers to profit aggregate routing. This is an efficient and effective approach to identify a best route to achieve required performance. It is noted from the literature survey that the Flow-Aware Multi-Topology Adaptive Routing (FAMTAR) was proposed for achieving higher Network performance through multipath solutions. This FAMTAR Model was implemented and studied thoroughly. From the experimental results, it was noticed that this model unable to i. detect and manage bulk flow, ii. Control Traffic Loss and iii. Maintain Deviation of Links Load against Traffic Load. To address the above mentioned issues, this research work is proposed an efficient Flow-Aware based Load Adaptive Routing (FA-LAR). This model is developed and implemented in ns3 and the simulation results are analysed carefully. From the experimental results, it is noticed that the prosed Model, FA-LAR is performing well as compared with the existing FAMTAR in terms of Queueing Delay, Throughput, Power Consumption (Energy Dissipation), and Load Deviation. It is also noticed that the proposed model unable to achieve higher Throughput for Low Load.
关键词： Load Balancing,Flow-Aware Network Models,Flow-Aware Multi-Topology Adaptive Routing,Routing Protocols,Flow-Aware Based Load Adaptive Routing
更新于2025-09-11 14:15:04
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Accelerated inactivation of <i>M13</i> bacteriophage using millijoule Femtosecond Lasers
摘要： Irradiation of femtosecond (fs) pulse lasers in the visible and near-infrared ranges have been proposed as a promising candidate for inactivating viruses. However, in order to achieve significant virus inactivation, past works have required relatively long irradiation times (1 hour or longer), even for small volumes. Given its advantages compared with other techniques, there is an urgent need to shorten the time required to inactivate viruses using fs laser technology. In this study, we investigate the inactivation of purified M13 bacteriophage in phosphate-buffered saline with large active volume (1 cm3), and short exposure time (several minutes), using lasers with 20 mJ/pulse energy at various wavelengths (800 nm, 400 nm or both 800 nm and 400 nm combined). For an exposure time of 15 min and 2 min, the use of a 400 nm wavelength laser results in a high load reduction of 5.8 ± 0.3 and 2.9 ± 0.15, respectively, on the log10 scale of viability. We show that virus inactivation using the 400 nm laser is much more efficient compared with that using 800 nm laser, or the simultaneous irradiation of 400 nm and 800 nm lasers. Higher pathogen inactivation is observed for lasers with shorter pulse duration, whereas at longer pulse durations, the inactivation is reduced. For millijoule-energy fs laser irradiation, the M13 bacteriophage inactivation, via the reduction of the functionality of M13 bacteriophages, is accompanied with relatively small amounts of genetic damage.
关键词： femtosecond laser,inactivation,M13 bacteriophage,load reduction
更新于2025-09-11 14:15:04
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A hybrid shuffled frog‐leaping and pattern search algorithm for load frequency controller design of a two‐area system composing of PV grid and thermal generator
摘要： The shuffled frog-leaping algorithm (SFLA) is a nature-inspired metaheuristic swarm-based optimization algorithm, which mimics the social behavior of memetics. The SFLA comprises an arrangement of communicating virtual population of frogs divided into various memeplexes. Many attempts have been made to find the variant of the SFLA that performs better on a variety of optimization tasks by making the original SFLA more complex. This paper proposes the hybrid approach by combining the SFLA algorithm with a pattern search algorithm, which improves the original technique named as the hybrid shuffled frog-leaping and pattern search algorithm (hSFLA-PS). The superiority of the proposed hybrid algorithm over the original SFLA in terms of implementation time and solution quality is compared by taking several benchmark test functions. In the next step, the real application of the proposed hybrid approach in the engineering field is done by designing a proportional-integral-derivative (PID) controller for frequency regulation of a two-area power system that is composed of a photovoltaic (PV) grid and a thermal generator. It is observed that the hSFLA-PS–based PID controller is more effective for the load frequency control compared with conventional controllers tuned with genetic algorithm (GA) and firefly algorithm (FA).
关键词： automatic generation control (AGC),multiarea multisource power system,maximum power point tracker (MPPT),hybrid shuffled frog-leaping and pattern search algorithm (hSFLA-PS),PID controller,load frequency control (LFC)
更新于2025-09-11 14:15:04
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[IEEE 2018 2nd IEEE Conference on Energy Internet and Energy System Integration (EI2) - Beijing (2018.10.20-2018.10.22)] 2018 2nd IEEE Conference on Energy Internet and Energy System Integration (EI2) - Photovoltaic-load model based-on load and power supply correlation
摘要： Photovoltaic power generation has become a non-negligible part of hybrid power generation in regions with sufficient solar energy or countries. Aiming at the correlation of light intensity and load fluctuations, this paper proposes a new photovoltaic-load model method for building correlations. The non-parametric kernel density estimation method was used to analyze the probability distribution of light intensity and node load, and the corresponding bandwidth was obtained. The correlation between light intensity and node load was analyzed by using Kendall rank correlation coefficient. The load nodes were divided into strong light intensity related nodes and illumination. There are two types of weakly correlated nodes; for the node with strong light intensity, the Copula function is used to establish the photovoltaic-load correlation model. For the weakly correlated nodes of light intensity, the Latin hypercube sampling method was used to establish the load fluctuation model. Finally, the 220kV system in B city is taken as an example to verify the practicability and effectiveness of the proposed model.
关键词： Photovoltaic power generation，Node load，Kendall rank correlation coefficient，Copula function
更新于2025-09-11 14:15:04
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Precision Measurement Method of Laser Beams Based on Coordinate Measuring Machine
摘要： This paper considers a load-aware energy ef?ciency maximization problem for downlink heterogeneous cellular networks with attention to unequal user priorities, load balance, quality of service (QoS) requirements, and power control. The load-aware energy ef?ciency of the networks is de?ned as the ratio of the effective rate and power consumption and mathematically formulated as a mixed-integer optimization problem in fractional forms with multi-constraints. A two-layer iterative algorithm with low computational complexity is proposed to address this optimization problem. In the outer layer, the objective function is converted into an equivalent problem in subtractive form by using the Dinkelbach method. The joint resource allocation involves cell-user association and power control that are decoupled over the independent portions of the system. In the inner layer, we search the association indices and transmit power parameters via solving a class of convex optimization problems governed by constraints. Speci?cally, by introducing some new auxiliary variables and using the Lagrangian dual method, the closed-form optimal association strategy and power control solution are obtained. The numerical simulations show that the proposed algorithm is guaranteed to converge and gives rise to higher energy ef?ciency than the existing one.
关键词： load management,energy ef?ciency,Heterogeneous networks,association rules
更新于2025-09-11 14:15:04
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Spectral Properties of Magnetohydrodynamic Turbulence Revealed by Polarization Synchrotron Emission with Faraday Rotation
摘要： Sensors of stress or strain currently used in geotechnical and civil engineering applications have the disadvantage that a large quantity of measuring points would result in large bundles of cables. Based on the principle of resistive strain gauge, a type of smart sensor that supports serial communication over RS-485 is developed for the measurement of strain or stress of foundation piles, which has the benefit of good noise tolerance. All the sensors installed along a pile could share a common cable for power supply and communication, and there is no actual limits to pile length. The installation in the field is simple, convenient and efficient. The sensor has a compact structure with reliable waterproof protection. The internal measurement circuit mainly consists of a Wheatstone bridge excitation module, a signal conditioning module, a microcontroller with ADC, a precision voltage reference, and a RS-485 communication module. A group of sensors were calibrated after being assembled, and the calibration results obtained have shown their functionality and reliability.
关键词： smart sensor,axial strain sensor,static load testing,RS-485 communication,foundation piles
更新于2025-09-11 14:15:04
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[IEEE 2019 Eleventh International Conference on Ubiquitous and Future Networks (ICUFN) - Zagreb, Croatia (2019.7.2-2019.7.5)] 2019 Eleventh International Conference on Ubiquitous and Future Networks (ICUFN) - Pricing-based shared energy storage optimization for residential users with photovoltaic generation system and demand-side load management
摘要： In this paper, we investigate a problem of optimal capacities of energy storage system for the residential users and an optimal unit price energy storage system for an aggregator. We suppose that the residential users have own photovoltaic generation system and a smart meter which can schedule activation of home appliances and controls. The aggregator participates in energy market to maximize his pro?t by selling the storage to the residential users. Each user determines his energy consumption schedule and a required amount of storage to minimize his energy cost depending on the unit price of energy storage, price pro?le of electricity from the main grid and his renewable power generation capacity. We consider electricity bill from main grid and storage bill from the aggregator as users’ energy cost. We formulate a problem for the aggregator to decide an optimal unit price of energy storage and a problem for each user to decide energy consumption schedule and a required amount of storage capacity. With numerical investigation, it is shown that the energy storage can reduce the energy load to main grid and shave peak power. As a result, by purchasing energy storage, users can save their energy cost by 43% in average compared to the case without energy storage.
关键词： home load management,Energy storage system,aggregator,residential photovoltaic generation,smart grids
更新于2025-09-11 14:15:04
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Tribological and adhesive properties of the tungsten-doped diamond-like carbon film prepared by double lasers deposition
摘要： The nanosecond and femtosecond lasers were used to ablate the graphite and tungsten targets simultaneously, and the tungsten-doped DLC ?lm with the di?erent tungsten concentration on the strip substrate was prepared. The content of the tungsten in the doped DLC ?lm varied continuously in the horizontal direction and was changeless in the vertical direction. The tungsten content in the doped DLC ?lm increased gradually when it was close to the center axis of the tungsten plasma generated by femtosecond laser. Surface roughness and the critical load of the tungsten-doped DLC ?lm increased with the increasing of tungsten content. On the other hand, the friction coe?cient of the tungsten-doped DLC ?lm decreased ?rstly and then increased when the tungsten content increased gradually. The minimal friction coe?cient was 0.086 when the tungsten content was about 8.07 at.%. The deposition method designed in this experiment also could be used for other doped ?lms in the ?eld of the function ?lms.
关键词： Continuously variated content,Critical load,Tungsten-doped DLC ?lm,Tribological property
更新于2025-09-11 14:15:04
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Solar irradiance estimations for modeling the variability of photovoltaic generation and assessing violations of grid constraints: A comparison between satellite and pyranometers measurements with load flow simulations
摘要： Global horizontal irradiance (GHI) is typically used to model the power output of distributed photovoltaic (PV) generation. On the one hand, satellite estimations are nonpervasive and already available from commercial providers, but they have a limited spatiotemporal resolution. On the other hand, local estimations, e.g., from pyranometers, sky-cameras, and monitored PV plants, capture local irradiance patterns and dynamics, but they require in situ monitoring infrastructure and upgrading the asset of electrical operators. Considering that in most power systems, PV generation is typically the aggregated contribution of many distributed plants, are local GHI estimations necessary to characterize the variability of the power ?ow at the grid connection point (GCP) and detect violations of the limits of voltages and line currents accurately? To reply, we consider GHI measurements from a dense network of pyranometers (used to model the ground truth GHI potential), satellite estimations for the same area, and information about a medium and low voltage distribution system. We perform load ?ows at different levels of installed PV capacity and compare the nodal voltages, line currents, and the power at the GCP when the irradiance is from pyranometers and when from satellite estimations, deriving conclusions on the necessity, or not, of highly spatiotemporally resolved irradiance estimations.
关键词： solar irradiance,grid constraints,satellite measurements,pyranometers,load flow simulations,photovoltaic generation
更新于2025-09-11 14:15:04