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Modeling,Parameter Measurement,and Control of PMSG-based Grid-connected Wind Energy Conversion System

Journal of Modern Power Systems and Clean Energy 2021年第5期9卷 1054-1065页

作者： Mohammad Kamruzzaman Khan Prince graduate Mohammad TArif Ameen Gargoom Aman MTOo Md Enamul Haque Renewable Energy&Electric Vehicle(REEV)Lab Centre for Smart Power&Energy Research(cSPER)School of EngineeringDeakin UniversityWaurn pondsAustralia

The design of reliable controllers for wind energy conversion systems(WECSs)requires a dynamic model and accurate parameters of the wind generator.In this paper,a dynamic model and the parameter measurement and control of a direct-drive variable-speed WECS with a permanent magnet synchronous generator(PMSG)are presented.An experimental method is developed for measuring the key parameters of the PMSG.The measured parameters are used in the design of the controllers.The generator-side converter is controlled using a vector control scheme that maximizes the power extraction under varying wind speeds.A model predictive controller(MPC)is designed for the grid-side voltage source converter(VSC)to regulate the active and reactive power flows to the power grid by controlling the d-and q-axis currents in the synchronous reference frame.The MPC predicts the future values of the control variables and takes control actions based on the minimum value of the cost functions.To comply with the grid code requirement,a modified design approach for an LCL filter is presented and incorporated into the system.The design process is simple and incorporates significant filter parameters while avoiding iterative calculations.The comparative analysis of the designed filter with conventional L,LC,and iterative LCL filters demonstrates the effectiveness of the modified design approach.The proposed wind energy system with MPC and LCL filter is simulated in MATLAB/Simulink and experimentally implemented in the laboratory using the dSpace digital signal processor(DSP)system.The simulation and experimental results validate the efficacy of the designed controllers using the measured parameters and show dynamic and steady-state performance under varying wind speeds.

关键词： Wind energy permanent magnet synchronous generator(PMSG) parameter measurement model predictive controller(MPC) LCL filter

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Localized Corrosion in Copper Tubes by Volatile Organic Substance

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 129-132页

作者： Takenori Notoya(Laboratory of Corrosion Engineering, graduate School of Engineering, Hokkaido University, Sapporo, Japan) Laboratory of Corrosion Engineering Graduate School of Engineering Hokkaido University Sapporo Japan

An unusual form of localized corrsion in copper tubes was detected early in service and in leakage tests after manufacturing.The morphology of this corrosion is similar to that of an ant's nest when viewed in cross se... 详细信息

关键词： copper tubes localized corrosion volatile organic substance heat-transfer units

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NUMERICAL MODELLING OF ROCK FALL USING EXTENDED DDA

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岩石力学与工程学报 2003年第6期22卷 926-931页

作者： Chen Guangqi (graduate School of Civil and Structural Engineering, Kyushu University, Fukuoka 816-8581 Japan) graduate School of Civil and Structural Engineering Kyushu University 日本 Fukuoka

The reasonable design of protective structures to mitigate the hazards from rock fall depends on the knowledge of motion behaviors of falling stones,such as the falling paths,velocities,jump heights and distances.Numerical simulation is an effective way to gain such kind of knowledge,In this paper,the discontinuous deformation analysis (DDA) is applied to rock fall analysis.In order to obtain more reliable results,the following improvements and extensions are made on the original DDA.(1)Solve the problem of block expansions due to rigid body rotation error.(2) Add the function of modeling the drag resistance from air and plants so that the velocities of falling stones obtained by simulations are good enough in agreement with those by experiments in situ.(3)Add the capability to consider energy loss due to block collisions so that the jumping heights and distances obtained by simulations are good enough in agreement with thos by experiments even for the slope with very soft layer on its surface.One of application examples is presented to show that the extended DDA is very effective and useful in rock fall analysis.Therefore,the presented method is expected to be put into wide use in slop stability analysis.

关键词：岩石力学 DDA 落石运动岩石力学能量损耗 DDA 边坡

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Applications of URANS on predicting unsteady turbulent separated flows

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Acta Mechanica Sinica 2009年第3期25卷 319-324页

作者： Jinglei Xu Huiyang Ma Department of Physics, graduate University of the Chinese Academy of Sciences, 100049 Beijing, China Department of Physics Graduate University of the Chinese Academy of Sciences Beijing China

Accurate prediction of unsteady separated turbulent flows remains one of the toughest tasks and a practi cal challenge for turbulence modeling. In this paper, a 2D flow past a circular cylinder at Reynolds number 3,900 is numerically investigated by using the technique of unsteady RANS （URANS）. Some typical linear and nonlinear eddy viscosity turbulence models （LEVM and NLEVM） and a quadratic explicit algebraic stress model （EASM） are evaluated. Numerical results have shown that a high-performance cubic NLEVM, such as CLS, are superior to the others in simulating turbulent separated flows with unsteady vortex shedding.

关键词： URANS Nonlinear eddy viscosity turbulencemodel ,Separated flows Circular cylinder

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THE　4~Σ-　STATES　OF　THE　FO　RADICAL

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Chinese Chemical Letters 1996年第5期7卷 475-478页

作者： Ming Bao HUANG (Department of Chemistry, graduate School, Academia Sinica, Beijing 100039) Department of Chemistry Graduate School Academia Sinica Beijing 100039

Abstract: For investigating the 4Σ- 4Σ- transition in the FO radical to which an observed 268 nm ASE line has been attributed. the potential energy energy of the four lowest-lying 4A2 states of FO have been calculated using the NIRSDCI method. The results indicate that the first 4Σ- (14A2) and the upper 4Σ- (44A2) States are weakly bound and bound states respectively, and the 24A2 and 34A2 States are both repulsive States which are not relevant to the emission. The predicted Te value for the 4Σ-→4Σ- transition is 4.62 eV, which is in excellent agreement with the photon energy value (4.63 eV) of the ASE line. The procedure of our MRSDCI calculations for excited states is described in detail, and the previous calculation results for these States are discussed.

关键词： ENERGY EXTRAPOLATION CI CALCULATIONS

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ON ASYMPTOTIC NORMALITY OF PARAMETERS IN LINEAR EV MODEL

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Chinese Annals of Mathematics,Series B 2002年第4期23卷 495-506页

作者： ZHANG SANGUO CHEN XIRUHua Lee-Keng Institue for applied Mathematics and Information Science, graduate School of ChineseAcademy of Sciences, Beijing 100039, China. Department of Mathematics, graduate School of Chinese Academy of Sciences, Hua Lee-Keng Institue for applied Mathematics and Information Science Graduate School of Chinese Academy of Sciences Beijing 100039 China Department of Mathematics Graduate School of Chinese Academy of Sciences Beijing 100039 China

This paper studies the parameter estimation of one dimensional linear errors-in-variables(EV) models in the case that replicated observations are available in some experimental points.Asymptotic normality is established under mild conditions, and the parameters entering the asymptotic variance are consistently estimated to render the result useable in construction of large-sample confidence regions.

关键词：非对称正态性参数估计变量误差模型回归模型重复观测

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Point Groups and Single Forms of Quasicrystals with Eightfold and Twelvefold Symmetry

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Acta Geologica Sinica(English Edition) 1989年第1期63卷 39-43页

作者： Shi Nicheng and Liao Libing Beijing graduate School, China University of Geosiences, Beijing Beijing graduate School China University of Geosiences Beijing

This paper mainly deals with the point groups and single forms of octagonal quasicrystals and the description of one-dimensional quasilattice. The authors present a new sequence for describing the arrangement of quasiperiods in one-dimensional quasilattice. The first ten numbers of quasiperiods of this sequence are 1, 1, 2, 5, 12, 29, 70, 169, 408 and 985. The arrangement of quasiperiods in the first five steps are a, b, ab. babab and babababbabab. Seven p(?)nt groups and nine single forms for the octagonal system have been deduced, They are as follows: Point groups: 8.8m, 82, 8/m, 8/mmm, 8 and 82m; single forms: octagonal prism, dioctagonal prism. octagonal pyramid. dioctagonal pyramid. octagonal dipyramid, dioctagonal dipyramid, octagonal scalenohedron, dioctagonal scalenohedron and octagonal trapezohedron. Besides seven point groups and nine single forms for the dodecahegonal system have also been deduced.

关键词： Point Groups and Single Forms of Quasicrystals with Eightfold and Twelvefold Symmetry

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Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part I: LiMn_2O_4 and LiCo_(0.5)Ni_(0.5)O_2

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Journal of Materials Science & Technology 1999年第6期15卷 509-514页

作者： Tomoki TSUMURA and Michio INAGAKI (graduate School of Engineering, Hokkaido University Kita-ku, Sapporo, 060-8628 Japan) graduate School of Engineering Hokkaido University Kita-ku Sapporo 060-8628 Japan NARD Institute Ltd. 2 Nishinagasu Amagasaki 660-0805 Japan Aichi Institute of Technology Yakusa Toyota 470-0392 Japan

Electrochemical insertion/extraction of Li on cathode materials of spinel type LiMn2O4 and ordered rock-salt type LiCo0.5 Ni0.5O2 was measured on samples of which structures were well characterized. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materiaIs on electrochemical Li insertion/extraction performance was discussed. These two transition metal oxides belong to onegroup that the crystallinity of these oxides affects to the performance.

关键词： LiMn2O4 and LiCo Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part I O2 Ni

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Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part Ⅱ: TiO_2, V_2O_5 and MoO_3

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Journal of Materials Science & Technology 2000年第1期16卷 5-14页

作者： Tomoki TSUMURA and Michio INAGAKI (graduate School of Engineering, Hokkaido University Kita-ku, Sapporo, 060-8628, Japan) graduate School of Engineering Hokkaido University Kita-ku Sapporo 060-8628 Japan NARD Institute Ltd. 2 Nishinagasu Amagasaki 660-0805 Japan Aichi Institute of Technology Yakusa Toyota 470-0392 Japan

Electrochemical insertion/extraction of Li on cathode materials of anatase type TiO_2, quasilayered structure V_2O_5 and layered structure MoO_3 was measured on samples of which structures were well characterized and showed a wide range of crystallinity. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materials on electrochemical Li insertion/extraction pedermance was discussed. These three transition metal oxides were classified as one group on the basis of whether the crystallinity of these oxides affects to the performance or not; LiMn_2O_4 and LiCo_(0.5)O_2 belongs to the former group and TiO_2, V_2O_5 and MoO_3 to the latter.

关键词： Li Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part V2O5 and MoO3

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A new resource for China

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Zoological Research 2016年第1期37卷 2-3页

作者： David B.WAKE the graduate School in Integrative Biology the Museum of Vertebrate Zoology,University of California at Berkeley Museum of Vertebrate Zoology University of California. wakelab@berkeley.edu.

n my country, as elsewhere nformation about animals. n the world, when one wants such as amphibians, one typically seeks out a field guide or a monograph. As the amphibian fauna around the world has grown （from about 4 000 species in 1985 to nearly 7 500 today）, the books, too, have become thicker, heavier, and more and more unwieldy. These books might contain features to assist identification-- written descriptions, keys, photographs and maps of the polygon variety and encompass known sites of occurrence. But the books quickly become out-of-date as knowledge increases and they rarely have information about phylogenetic relationships or display trees. But, we now live in a digital age, and young people, in particular, view books as old-fashioned and inadequate for their needs. The time is ripe for a new approach.

关键词： A new resource for China maps more

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