检索结果-内蒙古大学图书馆

2012 IEEE 7th International power Electronics and Motion control Conference - ECCE Asia, IPEMC 2012

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

ISBN: (纸本)9781457720864

Five-level active neutral-point-clamped (ANPC) converter is a newly emerging topology which can overcome the drawbacks of traditional neutral-point-clamped and flying-capacitor multilevel converters. During the start-up of the converter, it must be ensured that the switches and capacitors cannot be overvoltage and overcurrent due to the uncharged floating capacitors. In this paper, a floating capacitor self-precharge method is proposed which, by transferring the circuit into a booster, charges the floating capacitors to the reference voltage with a very small average load current. simulation and experimental results are presented to verify the validity of this method. © 2012 IEEE.

关键词： power converters

来源：评论

学校读者我要写书评

暂无评论

A Two-level Energy Storage System for Wind Energy systems

引用

Procedia Environmental Sciences 2012年 12卷 130-136页

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

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 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

来源：评论

学校读者我要写书评

暂无评论

Application of fuzzy-rough set theory and improved SMO algorithm in aircraft engine vibration fault diagnosis

Application of fuzzy-rough set theory and improved SMO algor...

引用

2012 3rd Annual IEEE Prognostics and System Health Management Conference, PHM-2012

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

Aircraft engine is an important component of the airplane, which lifespan and reliability have directly influence to flight safety. Vibration analysis is an effective fault diagnosis method for airplane's mechanical construction fault. Several typical vibration faults have drawn from the vibration analysis on the basis of fault mechanism in aircraft engine, and the standard vibration fault-symptom (Fuzzy Membership) relationship table have constructed based on Fuzzy Mathematic theory in this paper. Sample data are simulated on the basis of this table. Sequential Minimal Optimization (SMO) is a fast algorithm for training Support Vector Machines (SVM). The simulated result showed a great improvement on computation efficiency by selecting double threshold parameter for SMO algorithm than single threshold. In order to examine the algorithm's effect applying in the aircraft engine fault diagnosis, Radial Basis Function (RBF) Neural Network, C4.5 Decision Tree, SVM (chunking), Platt's SMO and Improved SMO algorithm are applied to the training data and test data. It is shown that the Improved SMO algorithm displayed superior comprehensive performance. Finally, the vibration fault feature is reduced based on Fuzzy-Rough Sets theory. The research shows that the Improved SMO algorithm is quicker than other algorithm in aircraft engine fault diagnosis with the reduced feature attributes, and its accuracy is high. © 2012 IEEE.

关键词： Support vector machines

来源：评论

学校读者我要写书评

暂无评论

Battery energy storage system load shifting control based on real time load forecast and dynamic programming

Battery energy storage system load shifting control based on...

引用

2012 IEEE International Conference on Automation Science and Engineering: Green Automation Toward a Sustainable Society, CASE 2012

作者： Bao, Guannan Lu, Chao Yuan, Zhichang Lu, Zhigang State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing 100084 China Electric Power Research Institute China Southern Power Grid Guangzhou 510080 China

ISBN: (纸本)9781467304283

Battery energy storage system (BESS) is one of the key technologies for smart grid and load shifting is one of the fundamental functions of BESS. BESS load shifting performance is determined by the availability of accurate load curves and optimization approaches. In this paper, a real-time control strategy based on load forecast and dynamic programming methods is presented. The predicted load curve is updated on-line through regress forecasting. The proposed optimization model is solved by using dynamic programming technique. The objective is peak shaving and prolonging the battery lifetime, and the constraints considered include battery state-of-charge (SOC), cycling times per day, converter capacity and step power. The above control strategy was successfully applied to the 5MW*4hour lithium-Ion BESS demonstration project in Biling substation, China Southern power Grid. The simulation results based on the actual load data of Biling substation demonstrate the effectiveness. © 2012 IEEE.

关键词： Dynamic programming

来源：评论

学校读者我要写书评

暂无评论

Study on control method of dual-motor for steer-by-wire system

Study on control method of dual-motor for steer-by-wire syst...

引用

2012 2nd International Conference on Consumer Electronics, Communications and Networks, CECNet 2012

作者： Zong, Changfu Xiang, Haiou He, Lei Sha, Fei State Key Laboratory of Automotive Simulation and Control Jilin University Changchun China School of Mechanical and Power Engineering Harbin University of Science and Technology Harbin China

ISBN: (纸本)9781457714153

In this paper, a structure of the steer-by-wire system with dual steering motors based on FlexRay bus has been proposed for meeting the real-time and reliability requirement of a steer-by-wire system. A control method is proposed to realize the coordinated control of dual steering motors. The control method has been verified experimentally. The results indicate that the control method can effectively achieve coordinated control of the dual steering motors and improve the safety of steer-by-wire vehicles. © 2012 IEEE.

关键词： Automobile steering equipment

来源：评论

学校读者我要写书评

暂无评论

Research on shielding failure of UHVDC based on leader progression model

Research on shielding failure of UHVDC based on leader progr...

引用

2012 31st International Conference on Lightning Protection, ICLP 2012

作者： Geng, Yinan Zhuang, Chijie Institute of Nuclear and New Energy Technology Tsinghua University Beijing China State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781467318976

Shielding failure is one of key problems of UHV transmission lines. Considering the high operating voltage and high tower of UHV transmission lines, the inception criterion of upward leader is proposed in this paper. The process of shielding failure is simulated by the method based on leader progression model and shielding failure rate is calculated. This method is verified by comparing the calculation results with the operated data of UHV transmission lines in Japan. The shielding failure characteristics of UHVDC transmission lines in China under different terrain conditions are researched. © 2012 IEEE.

关键词： Electric lines

来源：评论

学校读者我要写书评

暂无评论

A schedule power flow auto generating technology in day-ahead security validation

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2012年第20期36卷 68-73页

作者： Lin, Yi Sun, Hongbin Wu, Wenchuan Yu, Jun Zhang, Boming State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China National Electric Power Dispatching and Communication Center Beijing 100031 China

Formulation of day-ahead operation schedule for large-scale power grid requires security validation, including static security, dynamic and transient stability. It is an important and basic task for day-ahead security validation to generate an AC power flow that satisfies the demand of the schedule. A new method of generating the day-ahead schedule power flow is proposed, which consists in dividing the problem into two subproblems-the active subproblem and the reactive subproblem. The inconsistency of various kinds of schedule data is coordinated by solving the active subproblem, while a rational voltage distribution is achieved by solving the reactive subproblem. Both of the two problems are formulated as optimization models with constraints satisfied and are solved with an interior point algorithm. Numerical test results on the testing system and real power systems show that the method is capable of providing rational day-ahead schedule power flow. © 2012 state Grid Electric power Research Institute Press.

关键词： Numerical methods

来源：评论

学校读者我要写书评

暂无评论

Fault classification rules extraction of wind turbine based on C4.5 algorithm

Fault classification rules extraction of wind turbine based ...

引用

Prognostics and Health Management Solutions Conference - PHM: Driving Efficient Operations and Maintenance, MFPT 2012

作者： Chen, Jie Jiang, Dongxiang Yang, Wenguang Deng, Xiaowen Feng, Yongxin State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Beijing 100084 China Electric Power Institute Guangdong Grid Company Guangzhou 510080 China

Distinguishing fault types in early time can prevent wind turbines from breaking down. C4.5 algorithm, different from ID3 algorithm, which can deal with continuous parameters, should be a choice fault diagnosis method of wind turbine. This paper strives to extract fault classification rules of wind turbine based on data collected from a small wind turbine in laboratory using C4.5 decision tree and validate the rules extracted using another set of data. According to the solution, fault types such as mass imbalance of rotor, aero-dynamic asymmetry, yaw misalignment, gearbox and bearing fault and so on can be distinguished by the method presented in this paper.

关键词： Wind turbines

来源：评论

学校读者我要写书评

暂无评论

Multi-source information based current matching state estimation for distribution network

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2012年第16期36卷 53-57页

作者： Ju, Yuntao Wu, Wenchuan Cheng, Xueqi Zhang, Boming Sun, Hongbin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China Weifang Power Supply Bureau Shandong Provincial Power Corporation Weifang 261000 China

By taking into account the real-time measurement with low redundancy and of only partial current in distribution systems and referring to the quasi-real-time current measuring data of the metering system, the current matching technique is proposed to solve the distribution network state estimation. The matching current equations in the sense of optimal estimation and its systematic solution are deduced. Based on the assumption that the load power factor is stable, a quasi-real-time measurement generating method is proposed for loads. With boundaries demarcated by real-time current measurement, the distributed network is divided into several measured areas and current matching state estimation is made for each area. Numerical tests and results of an actual system show that the method proposed can satisfy the real-time application demand of the distribution system. ©2012 state Grid Electric power Research Institute Press.

关键词： state estimation

来源：评论

学校读者我要写书评

暂无评论

power transformer condition assessment by on-line monitoring and trend analysis

Power transformer condition assessment by on-line monitoring...

引用

IASTED International Conference on power and Energy systems and Applications, PESA 2012

作者： Xie, Qijia Gao, Shengyou Zhang, Hailong Dai, Wen Ruan, Ling Nie, Dexin Lu, Wenhua Key Laboratory of High-Voltage Field-Test Technique of SGCC Hubei Electric Power Testing and Research Institute Wuhan China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China State Grid Electric Power Research Institute Wuhan China School of Electrical Engineering Wuhan University Wuhan China

power transformer condition assessment is the basi of condition-based maintenance and plays a very important role in carrying assets management and risk assessment for power system. As the heart of transmission and transformation system, power transformer's condition has close relation with many factors, such as the production quality of itself, operation environment and so on. This paper analyzes some variables which could represent the transformer's condition, including the data from preventative test, factory test and commission test, diagnostic test, on-line detection and monitoring, routine inspection, operation history, family defection and environment information. Some parameters which have representation are chosen as the condition variables. Artificial neuron network (ANN) and Dempster-Shafer (D-S) evidence theory are adopted to form the multiparameter information fusion condition assessment model. Besides the static value, the change trends of some parameters are considered as an independent evidence section. Cooperating with on-line monitoring, it will be helpful to improve the accuracy and efficiency of condition assessment.

关键词： power transformers

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：