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Brazilian Power Electronics Conference, COBEP

作者： Nady Rocha Ely C. de Menezes Ítalo A. Cavalcanti de Oliveira Cursino B. Jacobina Electrical Engineering Department (DEE) Federal University of Paraíba (UFPB) Cidade Universitária - João Pessoa PB Brazil Post-Graduate Program in Electrical Engineering - PPgEE - COPELE Federal University of Campina Grande (UFCG) Campina Grande PB Brazil

This paper presents a generation system based on the induction generator for wind energy application. The induction generator is connected to single-phase grid through an ac-dc-ac single-phase to three-phase converter. The single-phase converter is composed of two parallel single-phase half-bridge converters. Suitable modelling, including the circulation current, and control strategy are developed. The control of generator is based on the field oriented control. A pulse width-modulation (PWM) technique using a single and double carriers PWM is presented. Proposed topology permits to improve the harmonic distortion. Beside, it can reduce the power losses in the converter. Finally, simulation and experimental results are presented.

关键词： Pulse width modulation Topology Estimation Induction generators Inductance Harmonic distortion

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The Creation and Application of a Simulator in Educational Robotics Classes

The Creation and Application of a Simulator in Educational R...

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IEEE Latin American Robotics Symposium, LARS

作者： Carla Fernandes Sarah Thomaz Renata Pitta Luiz Marcos Goncalves Post-Graduate Program in Electrical and Computer Engineering Federal University of Rio Grande do Norte Natal RN Brazil Department of Computer and Automation Engineering Federal University of Rio Grande do Norte Natal RN Brazil

ISBN: (纸本)9781479934775

Educational robotics classes consist of the use of robots in classes that involve interdisciplinary or social themes, creating innovative learning environments involving the use of such technology. In the usually known approach, educational robotics uses robotics kits. We developed a robotic simulator, called S-Educ, which can be used as an alternative or in association with robotics kits in classes involving the use of robotics. Simulators are not replacements of robotics kits, but an alternative for cases where the kits can not be used or they are not appropriate. Tests were carried out to analyze the use of the simulator, obtaining good results on the application of this simulator in educational robotics classes.

关键词： Robot sensing systems Virtual environments Mobile robots Actuators Wheels

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THREE-PHASE MULTIFUNCTION COMPENSATOR

THREE-PHASE MULTIFUNCTION COMPENSATOR

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Brazilian Power Electronics Conference

作者： E. L. L. Fabricio C. B. Jacobina A. M. Maciel Instituto Federal da Paraiba Post-Graduate Program in Electrical Engineering - PPgEE - COPELE Universidade Federal de Campina Grande

ISBN: (纸本)9781479902712

This work proposes a topology of compensator with the purpose of compensate harmonics and reactive loads or supply the load with balanced three-phase voltages, even when the grid voltage presents harmonics. The topologies have two operation modes. Mode A: acting as shunt active power filter and mode B: acting as ac-dc-ac converter. The model of the system is derived and a suitable control strategy, including the PWM technique, is developed. Experimental results are presented, as well.

关键词： Active Power Filter Parallel Converters Circulation Current Static Converters

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Functional movement modeling for robot-assisted upper limb rehabilitation: The case of a simulated reduced-freedom anthropomorphic manipulator

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Revista Brasileira de Engenharia Biomedica 2012年第1期28卷 3-10页

作者： Abadia, Fernando Gonçalves Santiago, Paulo Roberto Pereira de Oliveira, Marco Antônio Assfalk Vieira, Marcus Fraga Post-graduate Program of Electrical and Computer Engineering Federal University of Goiás - UFG Goiânia Go Brazil School of Physical Education and Sport of Ribeirão Preto University of São Paulo - USP Ribeirão Preto SP Brazil School of Electrical and Computer Engineering Federal University of Goiás - UFG Goiânia Go Brazil Laboratory for Bioengineering and Biomechanics Federal University of Goiás - UFG Mail Box 131 Zip Code 74001-940 Goiânia Go Brazil

This paper presents the results of an on-going investigation into the use of an anthropomorphic robotic manipulator with three degrees of freedom (two DOF shoulder joint and one DOF elbow joint) for rehabilitation of a human upper arm. The reduction to three DOF for this manipulator allows for a simpler project, leading to a lower cost of production and maintenance: important factors for its intended wide-spread use in financially restricted areas, e.g., the state of Goiás, Brazil. The project focuses on determining the variations observed for a class of trajectories known as functional movements. These functional movements are trajectories realized when a limb is used for a given function, e.g., combing the hair. In this present paper we use three functional movements: hair combing, bringing a cup to one's mouth and a waving movement. We describe how these functional movements are acquired from test subjects and compared in computer simulations to the equivalent functional movements of our proposed reduced-order anthropomorphic manipulator. Our research indicates that the errors incurred in using a reduced-order shoulder joint are well within the observed variation in the functional movements of human subjects, when compared among different subjects and also between similar functional movements of any one given human subject. Despite the limitations, the proposed manipulator would be viable for rehabilitation of patients in early phases of a stroke, at lower cost of production.

关键词： Patient rehabilitation

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Multiple Criteria Analysis for Energy Storage Selection

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Energy and Power engineering 2011年第4期3卷 557-564页

作者： Alexandre Barin Luciane N. Canha Alzenira R. Abaide Karine F. Magnago Breno Wottrich Ricardo Q. Machado Federal University of Santa Maria Post-Graduate Electrical Engineering Program Center for Energy and Environment Studies

In view of the current and predictable energy shortage and environmental concerns, the exploitation of renewable energy sources offers great potential to meet increasing energy demands and to decrease depend- ence on fossil fuels. However, introducing these sources will be more attractive provided they operate in conjunction with energy storage systems (ESS). Furthermore, effective energy storage management is essential to achieve a balance between power quality, efficiency, costs and environmental constraints. This paper presents a method based on the analytic hierarchy process and fuzzy multi-rules and multi-sets. By exploiting a multiple criteria analysis, the proposed methods evaluate the operation of storage energy systems such as: pumped hydro and compressed air energy storage, H2, flywheel, super-capacitors and lithium-ion storage as well as NaS advanced batteries and VRB flow battery. The main objective of the study is to find the most appropriate ESS consistent with a power quality priority. Several parameters are used for the investigation: efficiency, load management, technical maturity, costs, environmental impact and power quality.

关键词： Multiple Criteria Analysis Fuzzy Sets AHP Method Energy Storage Systems Power Quality

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Induced Currents and Planar Force in an Induction Planar Actuator

Induced Currents and Planar Force in an Induction Planar Act...

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Biennial Institute of electrical and Electronics Engineers Conference on Electomagnetic Field Computation

作者： Aly Ferreira Flores Filho Nolvi Francisco Baggio Filho Post-Graduate Program of Electrical Engineering Federal University of Rio Grande do Sul

ISBN: (纸本)9781424470594

The induction planar actuator (EPA) in study is an electromagnetic structure formed by a static ferromagnetic core with an aluminium plate that corresponds to the secondary, and a mover, also called primary;the latter comprehends two sets of three-phase windings that are orthogonal to each other. When they are fed by a three-phase ac excitation, a moving magnetic field is established;it can travel along the x-axis and the y-axis direction. The travelling magnetic field induces currents in the secondary;the interaction between those induced currents and travelling magnetic field produces a planar traction force responsible for the movement of the mover over the working area of the actuator. Induced currents and planar traction forces are studied by means of a finite element model, and experimental results are produced.

关键词： lateral axis actuators Aluminum sheet Orthogonal Planar magnetic field Work area finite element model Induced currents Traction force

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Variable air-gap hysteresimeter - An alternative method for the characterization of permanent magnets

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Journal of Microwaves and Optoelectronics 2009年第1期8卷 26S-37S页

作者： Filho, Aly F. Flores Anocibar, Hector R. Homrich, Roberto P. Laboratory of Electrical Machines Energy and Drivers Post-Graduate Program in Electrical Engineering UFRGS Av. Osvaldo Aranha 103 CEP 90035-190 Porto Alegre Rio Grande do Sul Brazil

The determination of the main magnetic properties of permanent magnets usually requires sophisticated and expensive measuring systems. This work analyzes and proposes a low-cost system for the characterization of Rare-Earth permanent magnets with linear characteristic that is simple to set up. Its magnetic circuit comprehends the permanent magnet under test, a steel yoke, a variable air-gap;a Hall-effect sensor connected to a Gaussmeter measures the flux density within the variable air-gap. The theoretical basis of the proposed measuring system, a description of its assembly, and the results it produces for a Neodymium-Iron-Boron permanent magnet will be presented. © 2009 SBMO/SBMag.

关键词： Permanent magnets

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A neural network modelling of steel joint block shear capacity

A neural network modelling of steel joint block shear capaci...

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9th International Conference on the Application of Artificial Intelligence to Civil, Structural and Environmental engineering, AICivil-Comp 2007

作者： Rodrigues, F. Neto, L. Biondi Da S. Vellasco, P.C.G. De Lima, L.R.O. Vellasco, M.M.B.R. Post-Graduate Program in Civil Engineering Brazil Electronic Engineering Department Brazil Structural Engineering Department State University Rio de Janeiro Brazil Electrical Engineering Department Pontifical Catholic University Rio de Janeiro Brazil

ISBN: (纸本)9781905088201

Despite the multiple failure modes associated to bolted steel joints the block shear failure is frequently the controlling limit state of gusset plates, tension members and coped beam joints. The block shear rupture is characterised by a condition where a steel block area, nearby the holes of bolted joint region, reaches its maximum capacity dictated by a tension to shear interaction. If the joint is loaded beyond this limit a steel block is eventually separated from the main structure. Many models have been proposed to avoid shear block failure in steel design. These models incorporate a combination of the various hypotheses that control the structural rupture. In the majority of cases, it involves a combination of rupture and yielding in the tension and shear planes of the designed joint. Various design formula for this structural engineering problem were proposed all over the years but a closed solution has not yet been reached, due to the influence of several independent parameters. Many studies have already been carried out with the available experimental data, however, non negligible errors are still present in the current design formulae. The main objective of the present paper is to present a back propagation neural network evaluation of the block shear phenomenon. The main neural network input parameters were the geometrical and material variables that control the block shear design. The neural network output parameter was the block shear capacity. The neural network training was based on experimental results present in literature and adopted cross validation techniques to avoid the neural network overfitting. The neural network results were promising, with reduced associated errors and confirmed the possibility of using this methodology to generate trustworthy data. These new data, coupled with the existent experiments, can help the production of more accurate design formulae. © Civil-Comp Press, 2007.

关键词： Neural networks

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Tfe Solberg Award

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Naval Engineers Journal 2009年第5期112卷

作者： Dr. Roy L. Streit Since 1992 Dr. Streit has focused a significant amount of his energy to assignment problems in acoustic warfare data fusion systems. This work led him to the formulation of the PDD Principle a broadly useful theoretical method that enables the derivation of new classes of discrete-continuous estimation algorithms for solving assignment problems without requiring enumeration and pruning. In recognition of his outstanding work in this area Dr. Streit received the NAVSEA Scientist of the Year Award for 1997. Dr. Streit has also been pursuing avenues for analyzing the loss in broadband detection performance of an acoustic array in the presence of interferences. Because examining all possible separations between the signal and many interferers is infeasible he has proposed a Poisson process model for the number and location (s) of the interferers. In this same time period Dr. Streit has also been investigating issues in environmental modeling and localization by proposing a novel integral method for solving the bearings-only target motion analysis problem which enables a natural heuristic for compensating for mismatch between the model predictions and the real world. Most recently Dr. Streit has proposed the Numerical ACoustic Hull ARray (NACHAR) Project as a revolutionary and ambitious approach to hull array design. Its premise is that optimizing the detection capability of large hull arrays requires the full integration of hull sensor array and beamformer design processes. Because NACHAR crosses an unusual number of technical disciplines it involves researchers from several departments. The diversity of Dr. Streif s technical background makes him uniquely suited to lead the project Dr. Streifs truly impressive scientific achievements are complemented by a noteworthy list of professional activities that accentuate his value to Division Newport and the Navy. He represents the United States in The Technical Cooperation Program Maritime Activities Panel 9 (Sonar Technology) and participates in the Division New

for his significant engineering research and development in sonar array research and acoustic transient signals as set forth in the following

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Real-time wavelet transform algorithms for the processing of continuous streams of data

Real-time wavelet transform algorithms for the processing of...

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2005 IEEE International Workshop on Intelligent Signal Processing

作者： Mota, Hilton De O. Vasconcelos, Fláio H. Da Silva, Rogério M. Post-graduate Program in Electrical Engineering Universidade Federal de Minas Gerais Belo Horizonte Brazil Electrical Engineering Department UFMG Belo Horizonte Brazil

ISBN: (纸本)078039030X

Two new algorithms to compute the direct and the inverse discrete wavelet transform of continuous streams of data are discussed in this paper. The algorithms are optimized to be used in uniprocessor systems, presenting as one of their main features the ability to compute over the borders of the data segments without relying on any techniques that are traditionally used for this task, like zero padding. A modified version of the Recursive Pyramid Algorithm was used to compute the direct transform, keeping just the features to minimize data storage but eliminating its dependency on extension techniques. The inverse transform is computed by an algorithm inspired in the RPA, the quadrature mirror filter bank and the overlap-save method for filter convolutions. To evaluate the performance the algorithms were implemented on a DSP coupled to a digitizer through its external memory bus, what allowed deterministic behavior. After a stage of optimization an analysis of data storage and computation load were made. These results and the potential applications are discussed at the end of the paper. ©2005 IEEE.

关键词： Data processing

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