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排序方式: 共有245条查询结果,搜索用时 15 毫秒
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Integration of PV system with SMES based on model predictive control for utility grid reliability improvement. 下载免费PDF全文
This paper describes the integration of a photovoltaic (PV) renewable energy source with a superconducting magnetic energy storage (SMES) system. The integrated system can improve the voltage stability of the utility grid and achieve power leveling. The control schemes employ model predictive control (MPC), which has gained significant attention in recent years because of its advantages such as fast response and simple implementation. The PV system provides maximum power at various irradiation levels using the incremental conductance technique (INC). The interfaced grid side converter of the SMES can control the grid voltage by regulating its injected reactive power to the grid, while the charge and discharge operation of the SMES coil can be managed by the system operator to inject/absorb active power to/from the grid to achieve the power leveling strategy. Simulation results based on MATLAB/Simulink® software prove the fast response of the system control objectives in tracking the setpoints at different loading scenarios and PV irradiance levels, while the SMES injects/absorbs active and reactive power to/from the grid during various events to improve the voltage response and achieve power leveling strategy. 相似文献
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Balaha Hossam Magdy Shaban Ahmed Osama El-Gendy Eman M. Saafan Mahmoud M. 《Neural computing & applications》2022,34(18):15907-15944
Neural Computing and Applications - Cardiovascular diseases (CVD) are the most widely spread diseases all over the world among the common chronic diseases. CVD represents one of the main causes of... 相似文献
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Performance optimization of integrated gas and power within microgrids using hybrid PSO–PS algorithm
In this paper, a hybrid algorithm consisting of particle swarm optimization and pattern search algorithm is proposed to evaluate and optimize the design and operation of microgrids (MGs) in combined gas and power networks. Key performance indicators (KPIs) are modeled and proposed to evaluate and assess MGs. The paper begins by proposing a comprehensive study to define KPIs, which are used to evaluate the following MG parameters: economical efficiency, reliability, environmental conservation, and power quality. Multi‐objective evaluation functions are then developed by building a relationship matrix of MG and KPI components. The results are then displayed as optimized power generation percentages for each technology with values for four KPI categories: cost, quality, reliability and environmental friendliness. Two case studies are examined in this paper; both the province of Ontario and Toronto regional zone under all system parameters with varying percentage of generation via gas technology. Results indicated that the optimal scenario for both Ontario and Toronto was achieved at hybrid PSO–patern search percentage generation via gas technology with improved cost KPI and other KPIs remaining approximately constant. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Z. Fattah A. Biabani-Ravandi A. Irankhah H. R. Arandiyan 《Chemical Engineering Communications》2016,203(2):200-209
The present work deals with the synthesis of nanostructured Co–MgO mixed oxides with different weight ratios of cobalt by a facile co-precipitation method as a catalyst for low-temperature CO oxidation. The prepared samples were characterized by X-ray diffraction (XRD), N2 adsorption/desorption (BET), Fourier transform infrared spectroscopy (FTIR), and transmission and scanning electron microscopies (TEM and SEM) techniques. The results revealed that inexpensive cobalt–magnesium mixed metal oxide nanoparticles have a high potential as catalyst in low-temperature CO oxidation. The Co–MgO mixed oxide with 30 wt.% cobalt had the highest activity. The results showed that the catalysts pretreated under O2-containing atmosphere possessed higher activity compared to the catalyst pretreated under H2 atmosphere. Co–MgO catalyst showed a good repeatability in reaction condition. The stability test exhibited that the Co–MgO mixed oxides were highly stable for CO oxidation over a 30 h time on stream in the feed gas containing a high amount of moisture and CO2. 相似文献
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The properties of high‐speed tool steels can be improved by modifying their chemical composition or the technology of production. Nitrogen alloying is an attractive technology to enhance the mechanical and physical properties of tool steels. In this work, modified super hard high‐speed tool steel was produced through nitrogen alloying and decreasing the level of cobalt content in investigated steels. This work aims to study the effect of nitrogen as alloying element on carbides and carbo‐nitrides precipitates type, shape, and size for investigated steels. From the results obtained from Thermo‐Calc, it was concluded that nitrogen alloying produced large amount of stable austenite, also eutectic carbides precipitates (M6C and M7C3) were stable at room temperature. Transmission electron microscope (TEM) images for traditional grade showed that the as cast structure contains beside the carbides network other single carbides precipitates. While on the other hand the selected area diffraction pattern (SADP) images of nitrogen alloyed grade shows fine carbides and carbo‐nitrides precipitates with more amount of retained austenite in the ferrite matrix, they showed also the presence of the eutectic precipitates as well as the dislocations. 相似文献
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This work is a seminal attempt to address the drawbacks of the recently proposed monarch butterfly optimization (MBO) algorithm. This algorithm suffers from premature convergence, which makes it less suitable for solving real-world problems. The position updating of MBO is modified to involve previous solutions in addition to the best solution obtained thus far. To prove the efficiency of the Improved MBO (IMBO), a set of 23 well-known test functions is employed. The statistical results show that IMBO benefits from high local optima avoidance and fast convergence speed which helps this algorithm to outperform basic MBO and another recent variant of this algorithm called greedy strategy and self-adaptive crossover operator MBO (GCMBO). The results of the proposed algorithm are compared with nine other approaches in the literature for verification. The comparative analysis shows that IMBO provides very competitive results and tends to outperform current algorithms. To demonstrate the applicability of IMBO at solving challenging practical problems, it is also employed to train neural networks as well. The IMBO-based trainer is tested on 15 popular classification datasets obtained from the University of California at Irvine (UCI) Machine Learning Repository. The results are compared to a variety of techniques in the literature including the original MBO and GCMBO. It is observed that IMBO improves the learning of neural networks significantly, proving the merits of this algorithm for solving challenging problems. 相似文献
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A multi‐objective evolutionary optimization of fuzzy controller for energy conservation in air conditioning systems 下载免费PDF全文
This paper presents the use of evolutionary optimization approach to design and tune smart fuzzy controllers for heating, ventilation, and air conditioning systems or HVAC. The objective is to optimize energy consumption while accounting for user comfort requirements. The problem of energy conservation in air conditioning systems becomes a multi‐objective optimization constrained problem, which enlarges the solution search space. To solve this problem, a multi‐objective evolutionary optimization technique based on genetic algorithm (GA) is proposed. A physical experimental setup is constructed for data collection and formulation of mathematical model. A fuzzy controller is initially designed through expert knowledge, and GA is then used to tune the rules and membership functions of the fuzzy controller in order to optimize multiple objectives. Simulations and real experiments are compared to determine the effectiveness of the proposed strategy. As compared to the controller present in the real experimental air conditioner, approximately 15% energy is successfully saved with no increase in average individual dissatisfaction or discomfort index. Also, a decrease in peak individual dissatisfaction or discomfort index from 91% to 62% is observed. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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High‐speed steels have been used mostly for multi‐point cutting tools and for plastic working tools. High speed steels are ferrous based alloys of the Fe‐C‐X multi‐component system where X represents a group of alloying elements comprising mainly Cr, W or Mo, V, and Co. The properties of these steels can be improved by modifying their chemical composition or the technology of their production. One of the new trends in modifying the tool steels chemical composition consists in the addition of niobium and nitrogen. In this work, the effects of niobium and nitrogen on morphology of carbides and secondary hardening temperature of investigated high speed tool steels were studied. This experimental work shows that, the conventional ingots have many types of carbides of different shapes and sizes precipitate on the boundary together with thick needle like carbides. On the contrary, for nitrogen steel, the nitrogen alloying leads to form dense, fine and well distributed microstructure. While, on the case of niobium alloying, single carbide (MC), and different types of eutectic carbides were precipitated which have a major effect on the secondary hardening temperature. 相似文献