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A kind of Low Leakage Inductance Planar Transformer

A kind of Low Leakage Inductance Planar Transformer

第六届IEEE国际电力电子与运动控制会议 (2009 IEEE 6th International power Electronics and Motion control Conference-ECCE Asia

作者： Li Hongzhu Yang Yugang Fred.C.Lee Wu Jiaju Liaoning Technical University/Institute of Electrical & Control Engineering Huludao125105China Virginia Polytechnic Institute and State University/Center for Power Electronics System BlacksburgV Nanchang Hangkong University/Nondestructive Test Key Laboratory of Ministry Education Nanchang33003

It's necessary to decrease the leakage inductance of transformer because it often produces a large voltage peak as device is turned off, meanwhile the large voltage peak is a source of EMI and produces a large voltage stress and affects the power supply's efficiency. This paper proposes a kind of low leakage inductance planar transformer with shunt magnetic circuit structure, the primary winding number of this structure can be decreased to 1 turn and the equivalent secondary winding can be decreased to less than 1 turn, therefore the leakage inductance can be decreased remarkably, and it can be used to various turns ratio of high frequency transformer expressly in the transformer of low voltage and large current power supply. This shunt magnetic structure is verified with Maxwell 3D.

关键词： Inductance power transformer insulation power supplies Magnetic circuits Electromagnetic interference Leg Stress Frequency Electronic equipment testing Transformer cores

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Overvoltage Suppression for UHV Transmission Lines

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Transactions of Tianjin University 2008年第3期14卷 222-225页

作者：李永丽刘太华李仲青景雷龙英范建忠 Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University ABB (China) Research Ltd.

The overvoltage phenomena of ultra high voltage (UHV) transmission lines are analyzed and verified by EMTDC/PSCAD simulation. Referring to the theoretical analyses and operating experiences of extra high voltage (EHV) transmission lines in China and UHV transmission lines in Russia and Japan, the methods to suppress the internal overvoltage in UHV transmission lines by protection and control strategies are discussed. Through the cooperation among the recloser, shunt reactor, tripping and closing resistance, and metal oxide varistor(MOV), the overvoltage can be restrained within an acceptable level.

关键词： overvoltage reclosing relay protection shunt reactors suppression UHV transmission lines

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Instantaneous energy balancing in three-level neutral point clamped converters

Instantaneous energy balancing in three-level neutral point ...

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2008 IEEE Vehicle power and Propulsion Conference, VPPC 2008

作者： Ting, Lu Zhengming, Zhao Liqiang, Yuan Shuping, Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781424418497

Instantaneous energy balancing plays an important role in power electronics conversion. The unbalance of electromagnetic energy not only debases the system performance but also decreases the reliability and efficiency of the conversion. In this paper, instantaneous energy balancing problems in three-level neutral point clamped (NPC) converters are classified and discussed. Typical examples and their usual solutions of each kind of problems are expounded and compared. In the end of this paper, limitations and disadvantages of traditional methods are analyzed, and electromagnetic field method is summarized as the new trend to analyze electromagnetic energy transmission and exchange. The method using electromagnetic field theory is emphasized to be the better approach to solve the aforementioned energy balancing problems. © 2008 IEEE.

关键词： Electromagnetic waves

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A novel modbus RTU-based communication system for adjustable speed drives

A novel modbus RTU-based communication system for adjustable...

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2008 IEEE Vehicle power and Propulsion Conference, VPPC 2008

作者： Sideng, Hu Zhengming, Zhao Yingchao, Zhang Shuping, Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781424418497

The communication protocol is important for applying adjustable speed drive (ASD) systems to an industry network. This paper proposes a novel scheme of communication system for the ASD system based on Modbus protocol. The most remarkable advantage of the approach lies in the tradeoff between performance and economic cost for a power converter system. The overall system is built on master-slave structure and easy for interacting with other networks. An additional study on the cyclic redundancy check (CRC) in Modbus RTU is introduced to obtain the optimization design in the actual application and the optimization method in software design is also presented. The performance of the communication system obtained from experiment conducted on the 15kW ASD system validates the effectiveness of the proposed design method. © 2008 IEEE.

关键词： Software design

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Intelligent controller for LEDs lighting systems supplied by batteries

Intelligent controller for LEDs lighting systems supplied by...

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2008 IEEE Vehicle power and Propulsion Conference, VPPC 2008

作者： Feng, Bo Zhao, Zhengming Zhang, Yingchao Zhou, Dejia Yuan, Liqiang State Key Laboratory of Control and Simulation Department of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781424418497

LED lighting system supplied by batteries is one of effective solutions to vehicle and photovoltaic lighting systems. In order to improve lighting performance and prolong the life of LEDs and batteries, this paper proposes a novel intelligent controller for LED lighting systems. Stage constant current (SCC) control strategy is proposed, which determines the optimal working current of LEDs (Iref) according to their ambient temperature and the capacity of batteries. For implementing SCC control strategy, a new control algorithm of double current loops and feedforward (DCLF) control is proposed based on Boost converter with constant current source. Both output current and inductor current are used as feedback control variables and input voltage is employed as feedforward compensation in the proposed algorithm. simulations have been conducted using PSIM software;and based on that, a 50W photovoltaic LED lighting system has been developed to implement a serial of comparative experiments. The results show the advantages and validity of DCLF algorithm, such as excellent dynamic performance and good robustness. © 2008 IEEE.

关键词： Light emitting diodes

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Single Phase-to-Ground Fault Line Identification and Section Location Method for Non-Effectively Grounded Distribution systems Based on Signal Injection

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Transactions of Tianjin University 2008年第2期14卷 92-96页

作者：潘贞存王成山丛伟张帆 Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin UniversityTianjin 300072ChinaSchool of Electrical EngineeringShandong UniversityJinan 250061China Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin UniversityTianjin 300072China School of Electrical Engineering Shandong UniversityJinan 250061China

A diagnostic signal current trace detecting based single phase-to-ground fault line identifica- tion and section location method for non-effectively grounded distribution systems is presented in this paper.A special diagnostic signal current is injected into the fault distribution system,and then it is detected at the outlet terminals to identify the fault line and at the sectionalizing or branching point along the fault line to locate the fault *** method has been put into application in actual distribution network and field experience shows that it can identify the fault line and locate the fault section correctly and effectively.

关键词： single phase-to-ground fault （SPGF） signal injection method fault line identification fault location

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Security region based real and reactive power pricing of power system

引用

Science China(Technological Sciences) 2008年第12期51卷 2095-2111页

作者： YU YiXin1 & WANG YanJun1,2 1 key laboratory of power system simulation and control of Ministry of Education,Tianjin University,Tianjin 300072,China 2 College of Mechanical and Electrical Engineering,Agriculture University of Hebei,Baoding 071001,China Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China College of Mechanical and Electrical Engineering Agriculture University of Hebei Baoding 071001 China

This paper develops a novel model and an algorithm of security region based real and reactive power pricing of power *** the proposed model,the reactive power production cost is represented as the opportunity *** static voltage stability region in the cut set power space(CVSR) and the practical dynamic security region(PDSR) in the injection power space are used to represent the constraints of voltage stability and transient stability,so that the consideration of this kind of constraints in the optimization becomes very *** the proposed algorithm,a decoupled optimization and iteration method of active power production cost and reactive power production cost is *** to the K-T optimality conditions,the prices of active power and reactive power,and the different components corresponding to the concerned security constraints are *** components of spot prices can reflect the influence of different node power injections on each kind of security constraints,so that through the node price all of the participants in power market can be stimulated to take an active part in maintaining the system *** illustrative example on the New England 10-genetator 39-bus system is used to demonstrate the proposed method.

关键词： static voltage stability region practical dynamic security region opportunity cost spot price active power and reactive power

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Design and implementation of the compact main circuit of IGBT-based converter

Design and implementation of the compact main circuit of IGB...

引用

2008 IEEE Vehicle power and Propulsion Conference, VPPC 2008

作者： Wang, Xuesong Zhao, Zhengming Yuan, Liqiang Zhang, Yingchao State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781424418497

The compact main circuit has many advantages, such as reducing volume and weight, saving costs and convenient for transportation. This paper presents three key problems including switching power supply, sampling and protection system, and cooling system. Through simplifying circuit and optimizing device parameters, the switching power supply can provide multiplex regulated power supplies with 540 VDC input directly. A simple circuit based on ripple principle can detect missing phase of input fault easily. The heat sink can be designed in a small volume through selecting suitable cooling fans, reducing switching frequency and setting minimum pulse width. A 15kW converter has been designed and implemented based on the above. Furthermore, this main circuit has been proved by practical application and long-term reliable operation. © 2008 IEEE.

关键词： Cooling systems

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Voltage stability control based on real power flow tracing

Voltage stability control based on real power flow tracing

引用

2008 IEEE Region 10 Conference, TENCON 2008

作者： Jinli, Zhao Hongjie, Jia Xiaodan, Yu Key Laboratory of Power System Simulation and Control Ministry of Education Tianjin University Tianjin 300072 China

ISBN: (纸本)1424424089

After some disastrous instabilities and blackouts, power system voltage stability has drawn even more attention. When a serious fault occurs, proper control should be quickly adopted to terminate the system deterioration. In this paper, a control method based on power flow tracing is presented to enhance power system voltage stability. Firstly, a branchadmittance-decreasing algorithm is introduced to determine the minimum power cutting after a serious fault. power flow tracing is then used to allocate the power to load and generator buses so as to get the corresponding load shedding and generation tripping. Comparing with the previous methods based on power flow sensitivity, the presented method can appropriately consider influence of some nonlinearities in power system, such as the discrete tap changing of OLTC, exciter hard-limit. Since power flow tracing is mainly used in the congestion management, allocation of power loss and transmission charges in the deregulation study, the presented method is compatible to the power system operation under deregulation. Finally, New-England system and IEEE 118-bus system are employed to verify the effectiveness of the presented method.

关键词： Deregulation

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A LMI based approach to power system stability analysis with time delay

A LMI based approach to power system stability analysis with...

引用

2008 IEEE Region 10 Conference, TENCON 2008

作者： Xiaodan, Yu Hongjie, Jia Jinli, Zhao Key Laboratory of Power System Simulation Control of Ministry of Education Tianjin University Tianjin 300072 China

ISBN: (纸本)1424424089

Delay margin means the maximum delayed time that power system can sustain without losing its stability. Since, there exists significant time delay in the data of phasor measurement unit (PMU) and wide-area measurement system (WAMS), to evaluate system delay margin is very important for power system online stability assessment and controller design in the wide-area environment. In this paper, we use Lyapunov stability theory and linear matrix inequality (LMI) method to evaluate power system delay margin. Lyapunov-Krasovskii criterion is firstly introduced to construct a suitable Lyapunov functional. Its derivative along the system trajectory is then expressed as a set of LMIs, which can be easily solved with LMI toolbox in Matlab or Scilab to obtain the system delay margin. In order to reduce conservativeness of the method, some slack variables are introduced in the derivation. Comparing with some existing numerical methods, such as eigenvalue based method, root clustering paradigm method, the presented method has a little conservativeness. However, it has much more flexibility and applicability in stability analysis to the time variant, nonlinear, switched and uncertain time delay systems. Finally, single-machine-infinite-bus (SMIB) system and WSCC 3-generator-9-bus system are employed to validate the effectiveness of the method.

关键词： Time delay

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