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IEEE Energy Conversion Congress and Exposition

作者： Sizhao Lu Zhengming Zhao Liqiang Yuan Ting Lu Yang Jiao Mingkai Mu Fred C. Lee State Key Laboratory of Power System Department of Electrical Engineering Tsinghua University Beijing China Center for Power Electronics Systems The Bradley Department of Electrical and Computer Engineering Virginia Tech Blacksburg VA 24061 USA

ISBN: (纸本)9781479957774

This paper presents a modularized high frequency high power 3-level neutral point clamped power electronics building block (PEBB) for renewable energy system. Three-level diode neutral point clamped (NPC) and 3-level active NPC are most popular topologies used in industrial applications based on modularized building block. However, since the single 3-level diode NPC or active NPC cell is unable to form a 3-level DC-DC chopper, the applications of PEBB cells based on these two circuits are limited where a DC-DC chopper is needed. In this paper, loss analysis for the 3-level chopper built by two 3-level diode NPC cells or active NPC cells are conducted. Switching loops in PEBB cells are identified, and double pulse tests are conducted for turn on and turn off transient of the switching loops. Based on double pulse tests, the switching losses will be quantified for different switching loops. Two 3-level bi-directional chopper circuits based on the active NPC PEBB cells are presented and compared. Then the modified PEBB cell derived from single active NPC cell is proposed for 3-level bi-directional chopper. Based on a common active NPC PEBB cell, the power converter can be built with modularized structure to achieve high frequency, high efficiency and low cost.

关键词： Switches Choppers (circuits) Switching loss Topology Renewable energy sources Power electronics

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Resolution analysis of the doppler-backprojection imaging method using TerraSAR-X parameters

Resolution analysis of the doppler-backprojection imaging me...

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作者： Wang, Ling Yazici, Birsen College of Electronic and Information Engineering Key Laboratory of Radar Imaging and Microwave Photonics of Ministry of Education Nanjing University of Aeronautics and Astronautics Nanjing210016 China Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute 110 8th Street TroyNY12180 United States

Conventional synthetic aperture radar (SAR) systems use wideband transmitted waveforms to obtain high range resolution images. Doppler-SAR [1, 2] or ultra-narrowband continuous waveform (CW) SAR uses ultra-narrowband transmitted waveforms and obtains high resolution by back projecting onto iso-Doppler contours. This paper describes the conceptual differences in understanding the difference in the resolution of wideband and Doppler-SAR images, and presents the resolution of Doppler-backprojection images when TerraSAR-X imaging parameters are used. © VDE VERLAG GMBH · Berlin · Offenbach, Germany.

关键词： Synthetic aperture radar

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BER and SER Analyses for M-ary Modulation Schemes Under Symmetric Alpha-Stable Noise

BER and SER Analyses for M-ary Modulation Schemes Under Symm...

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IEEE Global Communications Conference

作者： Fan Yang Xi Zhang School of Communication and Information Engineering University of Electronic Science and Technology of China Networking and Information Systems Laboratory Department of Electrical and Computer Engineering Texas A&M University

ISBN: (纸本)9781479935130

Symmetric alpha-stable (SαS) distribution has been widely used to model undesirable impulsive noise disturbance in many scenarios. Due to lack of probability density function (pdf) of SαS distribution (except Cauchy and Gaussian cases), the general closed-form expression of the bit error probability or symbol error probability for M-ary modulation schemes has not been derived yet, preventing the derivation of the exact coding gain from being feasible. By employing geometric power involved in zero-order statistics, we create a mapping mechanism which is consistently continuous along the entire range of characteristic values. Then we derive the accurate bit error probability and symbol error probability of M-ary modulation schemes under SaS noise. Our obtained derivations agree well with our simulations, which provide a unified framework for uncoded systems using M-ary modulation under additive white Gaussian noise (AWGN) and additive white symmetric alpha-stable noise (AWSαSN). Also, it enables the design of capacity approaching codes especially for higher-order modulation scenarios.

关键词： M-ary modulation Symmetric alpha-stable noise (SαS) Probability density function (pdf) Smart grid Non-Gaussian Geometric signal-to-noise ratio (GSNR) Zero-order statistics

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Model-based control of a dual active bridge for bidirectional feeding of DEAP transducers

Model-based control of a dual active bridge for bidirectiona...

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IEEE/ASME (AIM) International Conference on Advanced Intelligent Mechatronics

作者： Jürgen Maas Thorben Hoffstadt Department of Electrical Engineering and Computer Science Ostwestfalen-Lippe University of Applied Sciences Lemgo Germany Control Engineering and Mechatronic Systems Lab Ostwestfalen-Lippe University of Applied Sciences Germany

Transducers based on dielectric electroactive polymers (DEAP) use the electrostatic pressure to convert electrical into mechanical energy or vice versa. Since the achieved actuation or energy gain depends on the applied electric field, the authors present a model-based voltage control of a DEAP transducer driven by a Dual Active Bridge (DAB) with bidirectional energy flow. Therefore, first of all a model of the electric behavior of the DEAP is derived. Afterwards the DAB is described as an appropriate high voltage DC-DC converter topology to feed DEAPs. Based on the models of these two components, a discrete voltage controller is presented that ensures an operation with high dynamic and accuracy. Finally, the developed controller is validated by measurements feeding the DEAP transducer with the proposed DAB.

关键词： Voltage control Transducers Voltage measurement Polymers Transfer functions Bridge circuits Actuators

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A voltage control strategy for preventing cascading trips of large-scale wind power in centralized area

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Dianli Xitong Zidonghua/Automation of Electric Power systems 2014年第11期38卷 7-12页

作者： Ding, Tao Guo, Qinglai Sun, Hongbin Xu, Fengda Xu, Xiaofei Jia, Lin Department of Electrical Engineering Tsinghua University Beijing China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China North China Power Grid Co. Ltd. Beijing China

Cascading wind farm trips have brought new challenge to the wind power integration. Traditional reactive power optimization can achieve a desirable control result, but voltage security violation usually happens after N-1 contingency because of the redistribution of power flow and slow response by the reactive power compensator. Therefore, a reactive power optimization model is set up with security constraints, aiming to maintain the voltage within the security region under both normal condition and N-1 contingency. Besides, Benders decomposition method is employed to solve the complex model, dividing into one master and some slave problems. Iterative method is used between master and slave problems to obtain the optimal solution. Practical power grid with nine wind farms is tested, and the comparison of security constrained optimal power flow (SCOPF) and traditional optimal power plow shows that the SCOPF has better effect, which can maintain the voltage security under both normal condition and N-1 contingency. So it is an effective method to prevent cascading faults of multiple wind farms integrated into power grid. Finally, the relationship of maximum wind power integration, wind farm capacity and reactive power capacity of wind units is fully studied to provide certain help for the operation of wind farm. ©2014 State Grid Electric Power Research Institute Press

关键词： Wind farm

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Research on an axial-axial flux compound-structure PMSM with varying air gap to fulfill field-weakening control

Research on an axial-axial flux compound-structure PMSM with...

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International Conference on electrical Machines and systems (ICEMS)

作者： Jing Zhao Yashuang Yan Zhongxin Gu Zhen Chen Ping Zheng Key laboratory for Intelligent Control & Decision of Complex Systems Beijing Institute of Technology Beijing China Department of Electrical Engineering Harbin Institute of Technology Harbin China

ISBN: (纸本)9781479951635

A compound-structure permanent-magnet synchronous machine (CS-PMSM), which integrates two PMSMs, is a hybrid electric vehicle (HEV) power train concept. In order to meet the requirement of wide speed range of HEV, an axialaxial flux CS-PMSM with a new mechanical method of varying air gap to fulfill field-weakening control and to improve the operating speed range is investigated. The field-weakening principle of the axial-axial flux CS-PMSM with varying air gap is analyzed. The electromagnetic performances with air gaps varying are evaluated by 3D finite-element method (FEM). The principle of selecting original air gap is proposed with comprehensive consideration. The field weakening capability by varying air gap is evaluated based on the comparison with two other electric methods.

关键词： Air gaps Couplings Torque Stators Magnetic flux Hybrid electric vehicles Rotors

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Edge-Event Based Consensus in Networks with Common Time-Varying Delays

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IFAC Proceedings Volumes 2014年第3期47卷 8299-8304页

作者： Feng Xiao Tongwen Chen Huijun Gao Institute of Intelligent Control and Systems Harbin Institute of Technology Harbin 150080 China Department of Electrical and Computer Engineering University of Alberta Edmonton Alberta T6G 2V4 Canada

This paper studies the delay robustness of a class of periodically edge-event driven synchronous consensus protocols in time-invariant networks. These protocols have the benefits of improved performance at reduced communication and computation costs. Under the assumption that all information links share a common time-varying transmission delay, we give non-conservative estimates of the maximum allowable time-delay and event-detecting period for solving the average consensus problem in terms of the algebraic structure of interaction topologies. Furthermore, rigorous stability analysis shows that the proposed technique is also applicable to the asynchronous consensus with multiple time-delays.

关键词： Multi-agent systems event-based consensus sampled-data consensus time-delays

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Longitudinal control of vehicle platoons for stop-and-go waves mitigation

Longitudinal control of vehicle platoons for stop-and-go wav...

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International Conference on System Theory, control, and Computing (ICSTCC)

作者： Constantin F. Caruntu Cosmin Copot Corneliu Lazar Robin De Keyser Faculty of Automatic Control and Computer Engineering Gheorghe Asachi Technical University of Iasi Iasi Romania Department of Electrical energy Systems and Automation Ghent University Ghent Belgium

The increased traffic flow on both existing highways and city roads leads to the appearance of stop-and-go waves which have many disadvantages, e.g., increased risk of accidents, higher fuel consumption, increased pollution, increased wear of vehicle mechanical parts, driving stress and passenger discomfort. The platooning of vehicles could be the solution to this problem by enforcing them to follow each other and to maintain a safe distance between them. The advantages brought by this solution depend on ensuring the string stability of the vehicle platoon. In this paper the leader-follower system is employed to illustrate the stop-and-go waves mitigation. Several controllers (P, PI) were designed based on the conditions that have to be met in order to ensure the string stability of the vehicle platoon and comparisons were made with a controller based on the driver behavior.

关键词： Vehicles Mobile robots Accidents Stability criteria Transfer functions

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Software Maintenance Optimization Based on Stackelberg Game Methods

Software Maintenance Optimization Based on Stackelberg Game ...

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IEEE International Conference on Software Reliability engineering Workshops (ISSRE Wksp)

作者： Jing Zhao Yan-Bin Wang Gao-Rong Ning Cheng-Hong Wang Kishor S. Trivedi K-Y Cai Zhen-Yu Zhang Department of Computer Science and Technology Harbin Engineering University China Department of Industrial engineering Harbin Institute of Technology China Department of Automatic Control Beihang University China Department of Electrical and Computer Engineering Duke University USA The State Key Laboratory of Computer Science Chines Academy of Sciences China

Application servers (AS) of virtualized platform may suffer from software aging problem. In this paper, we first formulate the system model including three virtual machines. Two of them act as the main servers, and the third machine acts as the backup node. The motivation of our formulated model is that the relationship between the service provider and the service maintainer is collaborative as well as having different goals between them, the service provider as a leader wants to maximize his system availability, while the service maintainer wants to minimize his maintenance cost. Thus, the problem of maximizing availability and minimizing cost between the service provider and service maintainer is Stackelberg game based. Next, we assume that the AS degradation is caused by resource consumption due to memory leaks for the AS on the active VMs, and we present the system degradation states based on Markov renewal processes. We give the analytical definitions of threshold levels for R alert at each VM, which are used to determine the optimal rejuvenation schedules. In addition, we obtain the steady-state availability expressions for the system and the mean maintenance cost. Finally, we give the Stackelberg strategy with the open-loop information and the solutions for the game theory by a numerical illustration.

关键词： Software Aging Availability Games Maintenance engineering Degradation computer crashes

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ANN-based DTC scheme to improve the dynamic performance of an IM drive

ANN-based DTC scheme to improve the dynamic performance of a...

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7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014)

作者： K Bouhoune K Yazid M S Boucherit Power and Industrial Systems Laboratory Faculty of Electronics and Computer Science University of Science Algeria Process Control Laboratory Department of Electrical Engineering Polytechnic National School PO Box 182 10 Hassan Badi El-Harrach 16200 Algiers Algeria

In addition to simplicity, the DTC of the IM allows a good torque control in steady-state and transient operating conditions. However, high torque ripple is produced, which is reflected in speed estimation responses. It also increases acoustical noise and makes the voltage source inverter operated in high and variable switching frequency, requiring a high sampling frequency. In this paper, a simple effective ANN-based DTC of the induction machine is proposed. Neural networks with a simple architecture are designed and implemented in influential points of the direct torque control block of the three phase induction machine in order to improve its dynamic performance while preserving the DTC structure simplicity as much as possible. In particular, this paper proposes to reduce, on the one hand, the torque ripple and commutation frequency. Neural comparators are used to select the appropriate bandwidth for the torque and flux hysteresis controllers. Their aim is to optimize the ripple level in the developed torque and flux. On the other hand, a neural speed controller is designed in order to improve the system ability to respond rapidly to changes in process variables and mitigate the effects of external perturbations. The performance of the proposed control are tested in simulation and highlighted by comparing to the conventional DTC control based on conventional hysteresis comparators and conventional PI speed controller. The obtained results show the feasibility and good performances of the proposed control.

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