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2011 IEEE Energy Conversion Congress and Exposition (ECCE 2011)

作者： Fanbo He Zhengming Zhao Liqiang Yuan Sizhao Lu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457705427;9781457705410

A fast DC-link voltage controller is desirable to reduce the DC-link capacitor for PV inverters. This paper proposes a method for single-phase grid-connected PV inverters to remove the ripple component from the DC-link voltage signal and a scheme to regulate the DC-link voltage based on energy-balance analysis. The proposed scheme provides excellent dynamic performance as well as a function to prevent DC-link overvoltage by limiting the input power, which is verified by both simulation and experiments.

关键词： DC link Polydnaviridae dc-link capacitor Inventors Voltage regulators dynamic characteristics DC link voltage Scheme Voltage regulation link voltage

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Voltage Fluctuation Suppression Method of Floating Capacitors in a New Modular Multilevel Converter

Voltage Fluctuation Suppression Method of Floating Capacitor...

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2011 IEEE Energy Conversion Congress and Exposition (ECCE 2011)

作者： Kui Wang Yongdong Li Zedong Zheng Lie Xu State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457705427

Modular multilevel converter (MMC) is a newly emerging multilevel topology for high power applications in recent years. The voltage fluctuation problem of a new MMC topology is studied in this paper. In order to suppress the voltage fluctuation of the floating capacitors, a control method is proposed by injecting high frequency zero-sequence voltage and phase-to-phase circulating currents. It can be used to drive an induction motor with pump/blower-like load at low speed and improve the performance significantly. A low power three-phase five-level prototype is built up to validate this method.

关键词： Bridge circuits Fluctuations Capacitors Voltage fluctuations Voltage control Frequency modulation Time frequency analysis

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1.96 Tb/s (21$\,\times\,$100 Gb/s) OFDM Optical Signal Generation and Transmission Over 3200-km Fiber

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IEEE Photonics Technology Letters 2011年第15期23卷 1061-1063页

作者： Jianjun Yu Ze Dong Nan Chi ZTE Inc. Beijing China Department of Communication Science and Engineering State Key Laboratory of ASIC & System Fudan University Shanghai China Hunan University Hunan China Georgia Institute of Technology Atlanta GA USA Fudan University Shanghai China

A novel scheme to generate coherent 21 optical subcarriers with fixed frequency of 25 GHz is proposed and experimentally demonstrated. Using these optical subcarriers, we have successfully generated 1.96 Tb/s (21 × 100 Gb/s) polarization-multiplexing optical orthogonal frequency multiplexed (PM-OFDM) polarization multiplexed quadrature phase-shift keying (QPSK) optical superchannel signal with optical signal-noise ratio of each subchannel larger than 30 dB (0.1-nm bandwidth). We have transmitted this 1.96-Tb/s optical OFDM superchannel over 3200-km SMF-28 with amplification span of 80 km with erbium-doped fiber amplifier-only.

关键词： Optical polarization Optical fibers Optical amplifiers Optical filters Optical modulation Phase modulation

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Research on information capability based high-performance information sharing in the simulation grid

Research on information capability based high-performance in...

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2010 International Conference on Computer Modeling and simulation, ICCMS 2010

作者： Zhang, Ying-Chao Zhang, Jing Chen, Xin Yu, Qin-Zhang Zhang, Hao Beijing Institute of System Engineering National Key Laboratory of Science and Technology on Complex Systems Simulation Beijing China

ISBN: (纸本)9780769539416

For the purpose of achieving high-performance information sharing in the simulation grid, an information capability-based Three Phase High-performance Information Sharing Approach (TPHPISA for short) is advanced. The main idea of TPHPISA is selecting those information sources with highest information capability and executing the best query plan. To illustrate how TPHPISA works, an application example of implementing high-performance information sharing in the stock market simulation grid is thoroughly analyzed. At last, the searching efficiency and accuracy of TPHPISA are demonstrated through comparing with other similar method. © 2010 IEEE.

关键词： Information analysis

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Effect of acidic surface functional groups on Cr(Ⅵ) removal by activated carbon from aqueous solution

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Rare Metals 2010年第3期29卷 333-338页

作者： ZHOU Hualei CHEN Yunfa School of Applied Sciences University of Science and Technology Beijing Beijing 100083 China State Key Laboratory of Multi-phase Complex System Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China

The activated carbon with high surface area was prepared by KOH *** was further modified by H2SO4 and HNO3 to introduce more surface functional *** pore structure of the activated carbons before and after modification was analyzed based on the nitrogen adsorption *** morphology of those activated carbons was characterized using scanning electronic microscopy （SEM）.The surface functional groups were determined by Fourier transform infrared spectroscopy （FTIR）.The quantity of those groups was measured by the Boehm titration ***（VI） removal by the activated carbons from aqueous solution was investigated at different pH *** results show that compared with H2SO4,HNO3 destructs the original pore of the activated carbon more seriously and induces more acidic surface functional groups on the activated *** pH value of the solution plays a key role in the Cr（VI） *** ability of reducing Cr（VI） to Cr（III） by the activated carbons is relative to the acidic surface functional *** higher pH values,the Cr（VI） removal ratio is improved by increasing the acidic surface functional groups of the activated *** lower pH values,however,the acidic surface functional groups almost have no effect on the Cr（VI） removal by the activated carbon from aqueous solution.

关键词： activated carbon surface functional groups removal modification chromium（VI）

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Research on multi-agent based C4ISR effectiveness simulation and evaluation

Research on multi-agent based C4ISR effectiveness simulation...

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2010 International Conference on Computer Modeling and simulation, ICCMS 2010

作者： Zhang, Ying-Chao Feng, Ye Yu, Qin-Zhang Xin, Chen Beijing Institute of System Engineering National Key Laboratory of Science and Technology on Complex Systems Simulation Beijing China

ISBN: (纸本)9780769539416

The effectiveness evaluation of C4ISR is playing a more and more important role in its designing, developing and using. According to its characters, such as complexity and intelligence, the traditional evaluation methods and systems are not feasible and effective enough. In this paper, a multiagent based simulation and evaluation framework of C4ISR is advanced, which includes the architecture and the working procedure. The agent-based simulation model of C4ISR is put forward, according to which the C2 Agent, Armament Agent and the Evaluation Agent are founded. The interaction model between each agent is also designed. At final, based on the Swarm, a multi-agent based C4ISR effectiveness simulation and evaluation prototype is developed, through which NATO C2 effectiveness evaluation is thoroughly analyzed. © 2010 IEEE.

关键词： Multi agent systems

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Modeling and simulation of international politics evolution in crisis

Modeling and simulation of international politics evolution ...

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2010 International Conference on Computer Modeling and simulation, ICCMS 2010

作者： Yu, Qin-Zhang Zhang, Jing Zhang, Ying-Chao Beijing Institute of System Engineering National Key Laboratory of Science and Technology on Complex Systems Simulation Beijing China

ISBN: (纸本)9780769539416

Under the guidance of the theories of complex Adaptive system and Artificial Societies, modeling and simulation of international politics evolution in crisis was studied. The Model of International Politics Evolution (IPEM) in crisis based on Agent was built. The function and architecture of IPEM were introduced. Individual Agent , including Nation Agent, International Organization Agent and Environment Agent, was described in detail. A simulation experiment was executed to prove the effectiveness of the method proposed in the paper. © 2010 IEEE.

关键词： Adaptive systems

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An analytical approximation method for the linear source soil infiltrability measurement and its application

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Journal of Hydrology 2011年第3-4期411卷 169-177页

作者： L.L. Mao T.W. Lei V.F. Bralts The Key Laboratory of Modern Precision Agriculture System Integration Research College of Water Conservancy and Civil Engineering China Agricultural University Beijing 100083 China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation CAS and MWR Yangling Shaanxi 712100 China Department of Agricultural and Biological Engineering Purdue University West Lafayette IN 47906-1196 USA

Soil infiltrability is the fundamental feature for soil infiltration. There exist many soil infiltration rate measurement methods. In this paper, an analytical approximation solution to the mathematic model for soil infiltrability estimation with the linear source method ( Mao et al., 2008 ) is presented, based on the mass-balance principle, which, when the supplied flow rate is constant, produces a cumulative infiltration equivalent to the Lewis–Milne equation by ignoring water ponding at the soil surface ( Lewis and Milne, 1938 ). Both the wetted area-time function and the infiltrability-time function in the analytical solution were assumed as the forms of exponential functions. laboratory recorded data in the linear source experiments were used to estimate the wetted area-time function. Mass balance principle was used to estimate the infiltration-time function, as related to the wetted area-time function. The results calculated with the analytical solution and those estimated with the numerical solution and “direct” and “inverse” methods proposed by Philip and Farrell (1964) based on the Kostiakov and Philip infiltration models were compared. The precisions of these four methods were estimated based on the mass/water balance principle, by comparing the recovered water volume from the soil infiltrability-time functions and the actually supplied water. The analytical solution produced the lowest errors of 6.5%, as compared with 6.6–10.8% errors of the other three methods. The steady infiltration rate estimated with the analytical solution of the linear source method is 50.37 mm/h while the numerical solution underestimated the steady infiltration rate by 24.9% as 37.81 mm/h. The most important meaning of this analytical solution is that both the soil infiltrability and the cumulative infiltration can be expressed in analytical function and calculated from the determined continuous infiltration formula as well. This study provides a good alternative tool for rel

关键词： Infiltration Linear source method Analytical solution Philip model

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Analysis on non-detection zone of the islanding detection in photovoltaic grid-connected power system

Analysis on non-detection zone of the islanding detection in...

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International Conference on Advanced Power system Automation and Protection (APAP)

作者： YuGuo Fan Chen Li Institute of Electrical Power Engineering (North China Electrical Power University) Baoding 071003 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (North China Electric Power University) Beijing 102206 China

Until now, there is a great development in photovoltaic grid-connected power system. In addition, there is an ongoing research on the problems existed in the system. Islanding of photovoltaic grid-connected power system have adverse impact on power quality and utility equipments, affecting the performance of the utility even worse, it may damage people's lives. Islanding detection is a key consideration for grid-connected DG. The effects of islanding detection are not only subject to the strategy it employed, but also subject to the parameter setting. Non-detection zone (NDZ) is an important index to evaluate the performance of islanding detection. In this paper, the NDZs of active frequency drift and active frequency drift with positive feedback (AFDPF) are mapped into two different load space, i.e. L×C norm space and Q f0 × C norm space. Based on it, theoretical deductions are given and simulations are developed to validate the discussions.

关键词： Power systems Photovoltaic systems Phase locked loops Voltage control Phase frequency detector Q factor

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Characterization of silicon electro-optical modulators for microwave photonic links

Characterization of silicon electro-optical modulators for m...

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International Topical Meeting on Microwave Photonics (MWP)

作者： Xianshu Luo Xiaoguang Tu Junfeng Song Tsung-Yang Liow Qing Fang Peng Huei Lim Yongzhong Xiong Mingbin Yu G. Q. Lo Institute of Microelectronics ASTAR (Agency for Science Technology & Research) Singapore State Key Laboratory on Integrated opto-electronics College of Electronic Science and Engineering Jilin University Changchun China Optoelectronic System Laboratory Institute of Semiconductors Chinese Academy of Sciences (CAS) Beijing China Division of Microelectronics School of Electrical and Electronic Engineering Nanyang Technological University Singapore

In this submission, we present the characterization of a silicon electro-optical modulator using Mach-Zehnder interferometer structure. We characterize the transmission spectra upon various DC and RF voltage supplies with different input optical power. We show the slope efficiency dependence on the optical input power. We also measured the spur-free dynamic range of the modulator using two-tone method, showing an optical power dependent SFDR with maximum value of ~ 7.5 dBc.

关键词： Erbium-doped fiber amplifier Radio frequency Optical modulation Silicon High speed optical techniques Optical fiber communication

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