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Extending CSP to detect motor imagery in a four-class BCI

Journal of Information and Computational Science 2012年第1期9卷 143-151页

作者： Fang, Yonghui Chen, Minyou Zheng, Xufei Harrison, R.F. State Key Laboratory of Power Transmission Equipment and System Security New Technology Chongqing University Chongqing 400044 China School of Electronic and Information Engineering Southwest University Chongqing 400715 China College of Computer Science Sichuan University Chengdu 610065 China Department of Automatic Control and Systems Engineering University of Sheffield United Kingdom

Brain Computer Interface (BCI) provides a direct communication channel from brain to peripheral equipment. Common Spatial Patterns (CSP) is wildly used to extract features for electroencephalogram (EEG). However, basic CSP only suits two-class discrimination and is unable to solve multi-class discrimination problems. This paper proposes a modified CSP method termed Bisearch Common Spatial Patterns (BCSP) to solve a four-class BCI problem. In BCSP, the Fisher's Linear Discriminant Analysis (LDA) is used to discriminate among the four motor imagery tasks. The BCSP can effectively reduce the number of the basic CSP, and thus makes the overall classification procedure more efficient. The Graz BCI data set from the BCI 2008 competition be used to verify the effectiveness of the BCSP. simulation results show that BCSP has better performance than other extension schemes. © 2012 Binary Information Press January 2012.

关键词： Brain computer interface

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Test and Analysis of Conducted Disturbance Sources of the Truck Crane under Stable Conditions

Test and Analysis of Conducted Disturbance Sources of the Tr...

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International Symposium on Electromagnetic Compatibility

作者： Li Xiao Zhanqing Yu Shuiming Chen Bo Zhang Rong Zeng Chijie Zhuang Yang Zeng Xiaoying Yu Qian Zhang State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Research Institute Zoomlion Heavy Industry Science & Technology Development Co. Ltd.

ISBN: (纸本)9781467307185

The Electromagnetic Compatibility (EMC) is a major issue for the truck crane designing, due to the large dimension. The conducted disturbance sources of truck crane was measured under stable conditions, the time domain characteristics of possible conducted disturbance sources was analyzed, and typical waveforms were concluded to solve the EMC (Electromagnetic Compatibility) issue. The electromagnetic disturbance characteristics at different test points under different operation conditions were compared, and the influence of different factors was studied. The amplitude and frequency parameters of the major disturbance sources were compared with the standard immunity test pulses suggested by ISO7637-2. The differences between them indicate that the extant standard might not apply to the test of the truck crane. The presented results could form a basis for the development of a special standard for the EMC test of the truck crane and further relevant EMC research.

关键词： Truck crane EMC Conducted disturbance source Time domain characteristics Electromagnetic immunity test

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Mathematical models of the system-level safe operational areas of power electronic converters in plug-in hybrid electric vehicles

Mathematical models of the system-level safe operational are...

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作者： Wang, Xuesong Bai, Hua Zhao, Zhengming Yuan, Liqiang China Power Engineering Consulting Group Corporation Beijing 100011 China Kettering University Flint MI 48504 United States State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing 100084 China

With the development of plug-in hybrid electric vehicles (PHEVs), power electronics plays an increasingly important role in electric power train systems. The economic and reliable design of these power electronic systems, e.g., dc/ac inverter and battery charger, will be the inward search to popularize electric vehicles. As an extension of system-level safe operational areas (SSOAs) proposed in our previous literature, this paper details the criteria and mathematical models of SSOA for a battery charger and a three-phase two-level dc/ac inverter. Operational areas were established based on the SSOA. Thermal characteristics of the semiconductor devices, operational modes, and load characteristics were enclosed to enhance the mathematical models. Experiments on a 5-kW charger and a 55-kW/380-VAC inverter validated the effectiveness of SSOA. © 2011 IEEE.

关键词： Metals

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Experimental research of the upward leader inception from transmission line

Experimental research of the upward leader inception from tr...

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2011 7th Asia-Pacific International Conference on Lightning, APL2011

作者： Zeng, Rong Li, Zhizhao Yu, Zhanqing Zhuang, Chijie State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781457714665

Electro-Geometric Model (EGM) has been applied widely all over the world to evaluate the lightning shielding failure of transmission line. But with the increase of operation voltage to 1000 kV and tower height to more than 100 meters, some shortcomings of the traditional EGM model were found by many researchers. Leader Progression Model (LPM) was proposed to solve these problems. But some fundamental works, such as when the upward leader initiates and how it propagates, is still indistinct. An experiment was designed and implemented in this paper to simulate the electric field circumstance near the test transmission line while the lightning downward leader approached. The upward leader from the test transmission line was clearly observed. The inception voltage and characteristics was analyzed. The streamer and leader initiated from the ground wire and conductor bundle were compared. The experiment results show that the leader initiating from the ground wire is more active in the inception stage. The velocity of the upward leader acquired is about 1.2-3.0 cm/μs. © 2011 IEEE.

关键词： Electric lines

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Numerical simulation on Small Scale Straight-blade and Twisted-blade Vertical Axis Wind T

Numerical Simulation on Small Scale Straight-blade and Twist...

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2011 SSITE International Conference on Future Material Research and Industry Application(FMRIA 2011)

作者： Lv Yongzhe Jiang Dongxiang Jiang Yong State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University

This paper presents an analysis on the performance of vertical axis wind turbine of two types, namely straight-blade vertical axis wind turbine(SB-VAWT) and twisted-blade vertical axis wind turbine(TB-VAWT)An attempt of this simulation is to identify which type performs better in the same wind conditions and swept areaThree-dimensional computational fluid dynamics(CFD) was adopted in this analysis, after solid models of them were generatedPreliminary results of torque, power and aerodynamics in the fluid field were obtained for discussionFinally, there provided some guidance for future wind tunnel tests.

关键词： straight-blade vertical axis wind turbine twisted-blade vertical axis wind turbine numerical simulation performance aerodynamics

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Numerical simulation on Small Scale Straight-blade and Twisted-blade Vertical Axis Wind Turbine

Numerical Simulation on Small Scale Straight-blade and Twist...

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2011 International Conference on Energy and Environment(ICEE 2011)

作者： Lv Yongzhe Jiang Dongxiang Jiang Yong State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University

This paper presents an analysis on the performance of vertical axis wind turbine of two types, namely straightblade vertical axis wind turbine(SB-VAWT) and twisted-blade vertical axis wind turbine(TB-VAWT). An attempt of this simulation is to identify which type performs better in the same wind conditions and swept area. Three-dimensional computational fluid dynamics(CFD) was adopted in this analysis, after solid models of them were generated. Preliminary results of torque, power and aerodynamics in the fluid field were obtained for discussion. Finally, there provided some guidance for future wind tunnel tests.

关键词： straight-blade vertical axis wind turbine twistedblade vertical axis wind turbine numerical simulation performance aerodynamics

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Study on the loss reduction of high-efficient high-voltage series induction motors

Study on the loss reduction of high-efficient high-voltage s...

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2011 International Conference on Electrical Machines and systems, ICEMS 2011

作者： Lingyun, Bai Zhengming, Zhao Yi, Lei Shuping, Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China Beijing Command College of CAPF Beijing 100012 China Anhui Electrical Research Institute Hefei 230022 China

ISBN: (纸本)9781457710445

On the basis of analyzing the composition of losses in high-efficient high-voltage asynchronous motors, the approaches of increasing the efficiency of the motors is investigated in this paper. The approaches concern with the improvement of material, winding, fan, magnetic groove and so on. By taking the economy and efficiency into account synthetically, the design of the YKK series induction motors is carried on, and it is realized by software simulation. © 2011 IEEE.

关键词： Induction motors

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A Two-level Energy Storage system for Wind Energy systems

A Two-level Energy Storage System for Wind Energy Systems

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2011 International Conference on Energy and Environment(ICEE 2011)

作者： Xi Xiao Hu Yi Qing Kang Jinfeng Nie State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University

Wind power outputs fluctuate with the changing of wind speed. The use of energy storage equipment is considered a reasonable solution to suppress wind power fluctuations. An energy storage mode may have its disadvantages over the others, for example, capacity limits, dynamic response, higher prices or shorter lifetime. Moreover, wind power fluctuations are present at different frequencies, to demand the energy storage to offer power support in different time ranges. To improve the performance, in this paper, a combined energy storage mode is discussed to meet the short-term and longterm energy storage requirement for wind power. Short-term energy storage is designed to meet the fast-changing power, using such as super capacitors. Long-term energy is designed to meet the large-scale capacity requirement using Li-ion battery or Vanadium Redox Battery(VRB). By analyzing the actual data of wind power outputs, the capacities of the two kinds of energy storage means are given as an example of the method.

关键词： wind power energy storage capacity designing

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A Two-level Energy Storage system for Wind Energy systems

A Two-level Energy Storage System for Wind Energy Systems

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2011 International Conference of Environmental Science and Engineering（ICESE 2011）

作者： Xi Xiao Hu Yi Qing Kang Jinfeng Nie State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University

Wind power outputs fluctuate with the changing of wind speed. The use of energy storage equipment is considered a reasonable solution to suppress wind power fluctuations. An energy storage mode may have its disadvantages over the others, for example, capacity limits, dynamic response, higher prices or shorter lifetime. Moreover, wind power fluctuations are present at different frequencies, to demand the energy storage to offer power support in different time ranges. To improve the performance, in this paper, a combined energy storage mode is discussed to meet the shortterm and long-term energy storage requirement for wind power. Short-term energy storage is designed to meet the fast-changing power, using such as super capacitors. Long-term energy is designed to meet the large-scale capacity requirement using Li-ion battery or Vanadium Redox Battery(VRB). By analyzing the actual data of wind power outputs, the capacities of the two kinds of energy storage means are given as an example of the method.

关键词： Wind power energy storage capacity designing

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A predictive DC voltage control scheme for back-to-back converters based on energy balance modeling

A predictive DC voltage control scheme for back-to-back conv...

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International Conference on Electrical Machines and systems (ICEMS)

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

This paper presents a predictive control scheme of DC-link voltage for back-to-back converters based on energy balance modeling. Since the variation of DC-link voltage is affected by the energy mismatch between rectifier and inverter, the energy distribution in a rectifier-inverter is analyzed. Moreover, in order to calculate the input and output energy in one control period accurately, the grid current is regulated by predictive control and the instantaneous active power consumed by the induction motor is estimated. Then, an equation based on energy balance in one control period is established, and the DC-link voltage can be controlled by solving it. Finally, simulation results show that with the proposed control scheme, the back-to-back converter exhibits both good dynamic and steady-state performances.

关键词： Voltage control Induction motors Rectifiers Capacitors Vectors Pulse width modulation Inverters

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