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2011 International Conference on Electrical Machines and systems, ICEMS 2011

作者： Zou, Gaoyu Zhao, Zhengming Yuan, Liqiang Wang, Xuesong Lu, Ting State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781457710445

The key parameters of SOA (safe operating area) of semiconductor devices are hard to be measured when converter is operating, which is not helpful to protect converter at any time. On the other hand, surplus estimating method is widely used to design the main circuit. In order to guarantee the whole system works safely and improve utilization rate of devices, the concept of SSOA (systematic safe operating area) is presented. By determining the relationship of key parameters between devices and converter, the expression of SSOA is described quantitatively. Then it is implemented as a basic rule to design a back-to-back converter based on IGBT for 55kW induction motor optimally. Rated value of DC-link voltage and grid filter of the system is obtained reasonably as well. © 2011 IEEE.

关键词： Insulated gate bipolar transistors (IGBT)

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Machine condition classification using deterioration feature extraction and anomaly determination

Machine condition classification using deterioration feature...

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作者： Jiang, Dongxiang Liu, Chao State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing 100084 China

Condition classification has been widely used for assessing equipment status for machine condition monitoring and diagnostics. An engine was fitted with one temperature and two pressure sensors to study the machine conditions in prognostics with an added abnormal state, in addition to the conventional normal and failure states. This work enables a better classification capability in order to predict deterioration in the engine. Information related to three deterioration processes was collected, and preprocessed using singular point elimination, deviation value acquisition, and data normalization. Wavelet transforms were used to extract deterioration features with different mother wavelets. The mother wavelets were selected using t tests to optimize the wavelet selection. The deterioration was related to the amount of anomaly, with the abnormal states defined to distinguish the functional from the failure states. A Learning Vector Quantization (LVQ) neural network was used to classify the machine conditions, including normal, abnormal, and failure states. The results showed that the deterioration features defined using the Daubechies wavelet (db8) most strongly correlated with the original signal, so that the classification accuracy based on the deterioration features was greatly improved. The LVQ classification system had good accuracy for machine condition classification, and was adaptable to various engine conditions. © 2010 IEEE.

关键词： Deterioration

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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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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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Design and implement of an active damping LCL-filter for three-level voltage source PWM rectifier

Design and implement of an active damping LCL-filter for thr...

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2011 International Conference on Electrical Machines and systems, ICEMS 2011

作者： Liu, Chao Zhao, Zhengming Lu, Ting Yuan, Liqiang Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781457710445

Grid-connected LCL filter of voltage source PWM rectifier (VSR) can not only reduce the values of inductance, improve the system dynamic response, but also reduce the cost. However, LCL filter brings stability problem if no damping method is adopted. In order to guarantee the stability and high power factor of VSR at the same time, active damping control method rather than reactive damping method is required. Nowadays, the study on LCL filter is just for two-level VSR. In this paper, parameter design and damping method are being placed in three-level VSR for widely use. For a three-level PWM rectifier, a new parameter design method as well as active damping method is proposed and verified by Matlab-Simulink simulation and experiment. © 2011 IEEE.

关键词： Damping

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A neutral-point potential balancing algorithm for five-level ANPC converters

A neutral-point potential balancing algorithm for five-level...

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2011 International Conference on Electrical Machines and systems, ICEMS 2011

作者： Wang, Kui Li, Yongdong Zheng, Zedong State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing 100084 China

ISBN: (纸本)9781457710445

Five-level active neutral-point-clamped (ANPC) converter is a newly emerging topology which can overcome the drawbacks of traditional neutral-point clamped (NPC) converters and flying-capacitor (FC) converters. Its dc-link is subdivided into two equal parts and the main problem is the neutral-point (NP) potential balancing. In this paper, a NP potential balancing algorithm based on zero-sequence voltage injection is presented. By calculating the NP currents of all key zero-sequence voltages, the most appropriate zero-sequence voltage is selected to generate the demanded NP current. Moreover, by further limiting the span of injected zero-sequence voltages, the NP balancing algorithm can make the two IGBTs connected in series operate at fundamental frequency. A three-phase five-level ANPC inverter prototype was built up and experimental results are presented to verify the validity of this algorithm. © 2011 IEEE.

关键词： power converters

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

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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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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 parallel based real-time electromagnetic transient simulator for IPS

A parallel based real-time electromagnetic transient simulat...

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Electric Ship Technologies Symposium

作者： Gong, Yuan Chen, Laijun Chen, Ying Xu, Yin State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781424492725

IPS has many special characteristics, such as using multi-phase, multi-frequency and hybrid AC/DC devices. As a result, existing electromagnetic transient simulators developed for power systems on land do not apply to IPS. This paper aims to build up a parallel based real-time electromagnetic transient simulator for IPS. A fast multi-switching process method for parallel electromagnetic transient simulations is coined to handle the tremendous switch events in IPS. To solve the difficulties brought by multi-phase machines in IPS, a multilevel hybrid parallel algorithm is forged through the combination of component level and network level parallelization. Based on the key techniques mentioned above, a parallel simulator is built up. Through sufficient testing to typical examples of IPS, the accuracy and high-efficiency of the simulator are proved. © 2011 IEEE.

关键词： Simulators

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