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Acoustic Simulation of a Special Switched Reluctance Drive by Means of Field-Circuit Coupling and Multiphysics Simulation

GIET, M. van der; LANGE, E.; CORREA, D. A. P.; Chabu, Ivan Eduardo; Nabeta, Silvio Ikuyo; HAMEYER, K.
Fonte: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC Publicador: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Tipo: Artigo de Revista Científica
Português
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56.28%
The approach presented in this paper consists of an energy-based field-circuit coupling in combination with multi-physics simulation of the acoustic radiation of electrical machines. The proposed method is applied to a special switched reluctance motor with asymmetric pole geometry to improve the start-up torque. The pole shape has been optimized, subject to low torque ripple, in a previous study. The proposed approach here is used to analyze the impact of the optimization on the overall acoustic behavior. The field-circuit coupling is based on a temporary lumped-parameter model of the magnetic part incorporated into a circuit simulation based on the modified nodal analysis. The harmonic force excitation is calculated by means of stress tensor computation, and it is transformed to a mechanical mesh by mapping techniques. The structural dynamic problem is solved in the frequency domain using a finite-element modal analysis and superposition. The radiation characteristic is obtained from boundary element acoustic simulation. Simulation results of both rotor types are compared, and measurements of the drive are presented.

Projeto e construção de um motor elétrico linear aplicado à bioengenharia; Design and construction of a linear electric motor applied to bioengineering

Juliani, Aline Durrer Patelli
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/01/2011 Português
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Considerando-se o atual estagio de desenvolvimento das máquinas elétricas, tanto em termos de ferramentas computacionais auxiliares nas simulações e nos projetos, quanto de materiais e sistemas eletrônicos de acionamento e controle, propõe neste trabalho a construção de um dispositivo eletromecânico, na classe dos motores elétricos lineares, que atenda as necessidades e se aplique a bioengenharia, mais propriamente as próteses de membro superior, na forma de acionador translacional. Este dispositivo deve substituir os sistemas que utilizam motores elétricos rotativos com mecanismos de adaptação mecânica (roldanas, vários fios, redutores), que convertem o movimento rotacional em linear. Também, os dispositivos híbridos, como atuadores eletro-hidráulicos e eletropneumáticos, que necessitam de fontes de energia de naturezas diferentes da eletroeletrônica, podem ser substituídos pelas maquinas elétricas lineares. Uma revisão dos conceitos relacionados a área de bioengenharia e feita, destacando-se os mecanismos de transmissão existentes. E apresentada uma analise comparativa entre os principais motores lineares, enfatizando-se as características construtivas, as vantagens e as desvantagens de cada um, relacionados a aplicação. A escolha da maquina a ser projetada e construída recaiu no motor linear síncrono...

Transformação dq não senoidal para máquinas síncronas com imã permanente no rotor; Non-sinusoidal dq transformation for rotor permanent magnet synchronous machines

Monteiro, José Roberto Boffino de Almeida
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 19/12/2002 Português
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O presente trabalho apresenta uma transformação dq não senoidal e sua aplicação em máquinas síncronas com ímã permanente na superfície do rotor (MSIP) e forma de onda de FEM não senoidal. O modelo resultante da aplicação dessa transformação permite o controle direto do torque eletromagnético, permitindo reduzir as ondulações do torque produzido nesse tipo de máquina. A redução dessas ondulações em MSIPs não senoidais possibilita que esse tipo de máquina seja empregado em aplicações onde somente MSIPs senoidais, que possuem custo mais elevado, poderiam ser usadas. Simulações e resultados práticos, obtidos pela implementação do sistema de controle vetorial não senoidal desenvolvido, são apresentados no trabalho. Pelos resultados obtidos, pode-se verificar que o método proposto é eficaz na redução das ondulações do torque eletromagnético em MSIPs não senoidais.; This work presents a non-sinusoidal dq transformation and its application in permanent- magnet synchronous machines (PMSM) with a non-sinusoidal back-EMF waveform. The resulting model of the application of such transformation permits direct control of machine electromagnetic torque, which achieves the reduction of torque ripple. The reduction of torque ripple in non-sinusoidal PMSMs makes possible the use of this kind of PMSM instead of sinusoidal PMSMs...

Controle preditivo não-linear baseado em multimodelos aplicado ao motor de indução; Induction motor non-linear predictive control based on a multimodeling approach

Alex Pereira França
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 06/08/2010 Português
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Uma abordagem preditiva global-local para o controle de um motor de indução é apresentado nesta tese. O conceito de controle preditivo diz respeito a uma classe de controladores que tem se desenvolvido muito no âmbito do controle de sistemas de conversão de energia nos últimos anos, acompanhando o desenvolvimento da capacidade computacional dos sistemas microprocessados ao longo da última década. A técnica proposta é fundamentada numa lei de controle baseada em uin modelo identificado de um motor de indução. A identificação se dá de maneira experimental a partir da simulação de um motor de indução indiretamente orientado em função do fluxo do rotor, através de um modelo fuzzy do tipo Takagi-Sugeno TS com Funções de Base Ortonormal no consequente das regras.As ações de controle locais são combinadas são combinadas pela ativação das regras do modelo local devido, e a ação de controle global resultante é aplicada ao controle de velocidade do motor de indução. Este método permite ao controlador a inclusão nos parâmetros de controle das não-linearidades e restrições inerentes ao controle do máquinas elétricas; A predictive global-local approach technic for induction motor control is presented in this thesis. Predictive control is a very wide class of controllers that have found rather recent applications in the control of electrical machines. Research on this topic has been increased in the last years due to the possibilities of today s microprocessors used for control. The proposed technique is founded on a identified model based predictive control. The identification technique applied in this method is based on the black box modeling of a Indirect Rotor Flux Oriented Induction Motor in stationary reference system through Takagi-Sugeno-TS fuzzy models with orthonormal base functions - OBF - on the rules consequents. Control actions are matched by local activation of the model rule because local and global control action is applied to speed control of an induction motor. This method allows the inclusion in the control parameters of non-linearities and constraints inherent the control of electrical machines

Spatial instruction scheduling for raw machines

Swenson, Shane Michael, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 91 leaves; 3796872 bytes; 3806701 bytes; application/pdf; application/pdf
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Instruction scheduling on software exposed architectures, such as Raw, must be performed in both time and space. The complexity and variance of application scheduling regions dictates that the space-time scheduling task be divided into phases. Unfortunately, the interaction of phases presents a phase ordering problem. In this thesis, the structure of program scheduling regions is studied. The scheduling regions are shown to have varying characteristics that are too diverse for a single simple algorithm to cover. A new scheduling technique is proposed to cope with this diversity and minimize the phase ordering problem. First, rather than maintaining exact mappings of instructions to time and space, the internal state of the scheduler maintains probabilities for different assignments of instructions to time and space resources. Second, a set of small scheduling heuristics cooperatively iterate over the probabilistic assignments many times in order to minimize the effects of phase ordering. A simple spatial instruction scheduler for Raw machines based on this technique is implemented and shown to outperform existing spatial scheduling systems on average.; by Shane Michael Swenson.; Thesis (M. Eng.)--Massachusetts Institute of Technology...

Harmonic control of multiple-stator induction machines for voltage regulation

Holloway, Jack Wade, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 135 p.; 5191020 bytes; 5208501 bytes; application/pdf; application/pdf
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Small, one to a few horsepower, three-phase induction machines with three sets of electrically-isolated, magnetically-coupled stator winding circuits are described. A voltage inverter is developed and used to drive one set of the machine stator winding circuits. The second set of machine stator winding circuits is connected to a three-phase rectifier in which a path for zero-sequence current is provided from the winding circuits to the rectifier. The last set of stator winding circuits is connected to another three-phase rectifier, however, the stator circuit star point is floating, not providing a zero-sequence current path. By controlling the phase of the third harmonic on the machine drive stator circuits, and thus the waveforms present on the secondary and tertiary stator winding circuits, the output voltage of the rectifier with a zero-sequence current path can be tune above or below the rectifier output without third harmonic injection. The rectifier connected without a zero-sequence current path does not display this tunability with respect to third harmonic phase.; by Jack Wade Holloway.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.; Includes bibliographical references (p. 133-135).

Model reduction through an Hankel problem and finite state machines

Jameson, Neal Ward, 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 30 p.; 950515 bytes; 951246 bytes; application/pdf; application/pdf
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(cont.) computation required to produce the approximation is O((n2̂)/[epsilon]) where [epsilon] is the desired ℓ[omega] error and n is the original system order.; The problem of linear time invariant model reduction seeks to transform a given model into a model that has fidelity to the original but allows for easier completion of desired tasks such as controller design and simulation. Hankel-norm approximation consistently performs very well in terms of H[omega] error and provides lower bounds on how well any model can approximate the given model; however, it requires substantial and sometimes prohibitive computation to produce the reduced system and calculate the lower bounds. Here we present a Hankel like approximation problem that allows easier computation of lower bounds. It is shown that the lower bounds produced by the new method do a reasonable job of approximating the lower bounds produced by Hankel-norm approximation. On the negative side, It is also shown that, for the new Hankel problem, there can be no theorem analogous to the major theorem of Hankel-norm approximation that actually produces a reduced model. For nonlinear model reduction, model order does not always predict how difficult it is to perform desired tasks...

Control and design of multi-use induction machines : traction, generation, and power conversion

Avestruz, Al-Thaddeus
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 159 p.
Português
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An electrical machine can be made to convert electrical power while performing in its primary role of transforming electrical energy into mechanical energy. One way of doing this is to design the machine with multiple stator windings where one winding acts as a primary for drive and power, and the others as secondaries for electrical power. The challenge is to control the mechanical outputs of torque and speed while independently regulating the electrical outputs of voltage and current. This thesis analyzes and demonstrates an approach that takes advantage of topological symmetries in multiphase systems to overcome this challenge. This method is applied, but not relegated to induction machines.; by Al-Thaddeus Avestruz.; Thesis (S.M. and Elec. E.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.; Includes bibliographical references (p. 157-159).

Approximation algorithms for stochastic scheduling on unrelated machines

Scott, Jacob (Jacob Healy)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 67 p.
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Motivated by problems in distributed computing, this thesis presents the first nontrivial polynomial time approximation algorithms for an important class of machine scheduling problems. We study the family of preemptive minimum makespan scheduling problems where jobs have stochastic processing requirements and provide the first approximation algorithms for these problems when machines have unrelated speeds. We show a series of algorithms that apply given increasingly general classes of precedence constraints on jobs. Letting n and m be, respectively, the number of jobs and machines in an instance, when jobs need an exponentially distributed amount of processing, we give: -- An O(log log min {m, n} )-approximation algorithm when jobs are independent; -- An 0 (log(n + m) log log min {m, n})-approximation algorithm when precedence constraints form disjoint chains; and, -- An O(log n log(n + m) log log min {m, n} )-approximation algorithm when precedence constraints form a directed forest. Very simple modifications allow our algorithms to apply to more general distributions, at the cost of slightly worse approximation ratios. Our O(log log n)-approximation algorithm for independent jobs holds when we allow restarting instead of preemption. Here jobs may switch machines...

Power inverter for photovoltaic plant and expertise in power control for wind generators

Arnaltes Gómez, Santiago
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Relatório Formato: application/pdf
Publicado em 14/04/2008 Português
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The Power System Control Group of a Madrid based university has developed a technology that allows the control of power inverters for photovoltaic plants grid connection. The research group has a great deal of experience in R&D projects dealing with the modelling and control of electrical machines, mainly for wind energy and photovoltaic applications, and renewable energy grid integration. They are seeking companies in these energy sectors, for a technical cooperation

Estratégias de acionamento e controle em máquinas CA de ímã permanente com fluxo não senoidal; Control strategies for permanent magnet AC machines with non-sinusoidal flux

Monteiro, José Roberto Boffino de Almeida
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/08/1997 Português
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O objetivo desse trabalho é o estudo e a análise do desempenho de máquinas brushless com ímã permanente no rotor, com fluxo de entreferro não senoidal. São consideradas máquinas brushless com ímã permanente na superfície do rotor. Três modelos matemáticos são considerados: o modelo por fase de estator, o modelo vetorial e o modelo velocidade-tensão de segunda ordem. Máquinas com diferentes tipos de enrolamento de estator são comparadas, incluindo as máquinas síncronas com ímã permanente no rotor (com a densidade dos enrolamentos distribuída de forma senoidal no estator). Os resultados para o torque eletromagnético das máquinas foram obtidos considerando-se dois tipos de acionamentos em malha aberta: um acionamento de seis pulsos e um acionamento senoidal. Por fim, um método de controle é apresentado para máquinas não senoidais. As ondulações no torque e o desempenho das máquinas não senoidais. As ondulações no torque e o desempenho das máquinas não senoidais, utilizando controle vetorial, são comparados aos das máquinas senoidais.; The aim of this work is to analyse the torque performance of brushless machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brushless machine. Three mathematical models for the machine are considered: the per stator phase...

Inductive Sensor for measuring partial discharges in electrical machines

Robles Muñoz, Guillermo; Sanz Feito, Javier; Martínez Tarifa, Juan Manuel
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Relatório Formato: application/pdf
Publicado em /05/2009 Português
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The research group 'Diagnosis of Electrical Machines and Insulation Materials (DIAMAT) of the University Carlos III of Madrid, has developed an inductive sensor that can detect and measure partial discharge that are characteristic in electrical machines (its analysis allows to estimate the aging degree of the internal insulation).

Modélisation causale pour la commande auto adaptée de machines alternatives triphasées en mode dégradé

CREVITS, Yvan; KESTELYN, Xavier; LEMAIRE-SEMAIL, Betty; SEMAIL, Eric
Fonte: HERMES Publicador: HERMES
Português
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Version éditeur disponible à cette adresse : http://ejee.revuesonline.com/article.jsp?articleId=14944; After a short historic of the multiphase machines and the state of the art of their open-circuited phase operation, this paper deals with a decoupled three-phase motor drive using a synchronous or induction machine. The modeling of this system uses a vectorial formalism and the energetic macroscopic representation (EMR) applied to normal and open-circuited mode operations. The resultant model is available in the two cases. It is permitted to bring to light the magnitudes evolution and leads to elaborate a “universal” command. This study is achieved with simulation validations, evaluation of the performances and some experimental validations. In conclusion, this method is considered for electrical machines supplied with more than three phases.

Contribution to the MHD modeling in low speed radial flux AC machines with air-gaps filled with conductive fluids

MENANA, Hocine; CHARPENTIER, Jean-Frederic; GABILLET, Celine
Fonte: IEEE Publicador: IEEE
Português
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This work deals with the modeling of the magnetohydrodynamic (MHD) phenomena in the air-gaps of low speed radial flux AC electrical machines filled with incompressible and electrically conductive fluids. The proposed model concerns laminar flows and it is based on a weak MHD coupling at the steady state regimes. The MHD power losses are evaluated and discussed. The model is easy to implement and could be a useful tool for the design and the optimization. An application to marine current turbine is considered.

Magnetic machines and power electronics for power MEMS applications

Das, Sauparna, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 323 p.; 16921694 bytes; 16936400 bytes; application/pdf; application/pdf
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This thesis presents the modeling, design, and characterization of microfabricated, surface-wound, permanent-magnet (PM) generators, and their power electronics, for use in Watt-level Power MEMS applications such as a microscale gas turbine engine. The generators are three-phase, axial-flux, synchronous machines, comprising a rotor with an annular PM and ferromagnetic core, and a stator with multi-turn surface windings on a soft magnetic substrate. The fabrication of the PM generators, as well as the development of their high-speed spinning rotor test stand, was carried out by collaborators at the Georgia Institute of Technology. The machines are modeled by analytically solving 2D magneto-quasistatic Maxwell's Equations as a function of radius and then integrating the field solutions over the radial span of the machine to determine the open-circuit voltage, torque and losses in the stator core. The model provides a computationally fast method to determine power and efficiency of an axial-air-gap PM machine as a function of geometry, speed and material properties. Both passive and active power electronics have been built and tested. The passive power electronics consist of a three-phase transformer and diode bridge rectifier.; (cont.) The active power electronics consist of a switch-mode rectifier based on the boost semi-bridge topology which is used to convert the unregulated AC generator voltages to a regulated 12 V DC without the need for rotor position/speed or stator terminal current/voltage sensing. At the rotational speed of 300...

Auditing technology for electronic voting machines; voter verification audio audit transcript trail

Cohen, Sharon B
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 96 leaves; 5045752 bytes; 5050901 bytes; application/pdf; application/pdf
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Direct Recording Electronic (DRE) voting machine security has been a significant topic of contention ever since Diebold voting machine code turned up on a public Internet site in 2003 and computer scientists at Johns Hopkins University declared the machine "unsuitable for use in a general election." Since then, many people from computer scientists to politicians have begun to insist that DREs be equipped with a paper trail. A paper trail provides a paper printout for the voter to approve at the end of each voting session. Although there have been strong political efforts to place paper trails on DRE machines, there have not been any scientific studies to indicate that paper trails are effective audits. This work describes a user study done to compare paper trails to audio audits, a new proposal for DRE auditing. Participants in the study completed four elections on a voting machine with a paper trail and four elections on a machine with an audio trail. There were purposeful mistakes inserted into the audits on some of the machines. Results from the study indicated that participants were able to find almost 10 times as many errors in the audio audit then they were able to find in the paper trail. Voters' attitudes towards the paper audit were extremely apathetic...

Development of magnetic induction machines for micro turbo machinery

Köşer, Hür, 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 183, 17, [1], 40, 23 p.; 21327755 bytes; 21327513 bytes; application/pdf; application/pdf
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This thesis presents the nonlinear analysis, design, fabrication, and testing of an axial-gap magnetic induction micro machine, which is a two-phase planar motor in which the rotor is suspended above the stator via mechanical springs, or tethers. The micro motor is fabricated from thick layers of electroplated NiFe and copper, by our collaborators at Georgia Institute of Technology. The rotor and the stator cores are 4 mm in diameter each, and the entire motor is about 2 mm thick. During fabrication, SU-8 epoxy is used as a structural mold material for the electroplated cores. The tethers are designed to be compliant in the azimuthal direction, while preventing axial deflections and maintaining a constant air gap. This enables accurate measurements of deflections within the rotor plane via a computer microvision system. The small scale of the magnetic induction micro machine, in conjunction with the good thermal contact between its electroplated stator layers, ensures an isothermal device which can be cooled very effectively. Current densities over 109 A/m2 simultaneously through each phase is repeatedly achieved during experiments; this density is over two orders of magnitude larger than what can be achieved in conventional macro-scale machines. More than 5 Nm of torque is obtained for an air gap of about 5 zm...

Generalization Performance of Regularization Networks and Support Vector Machines Via Entropy Numbers of Compact Operators

Williamson, Robert; Smola, Alexander; Schoelkopf, Bernhard
Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc) Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)
Tipo: Artigo de Revista Científica
Português
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46.22%
We derive new bounds for the generalization error of kernel machines, such as support vector machines and related regularization networks by obtaining new bounds on their covering numbers. The proofs make use of a viewpoint that is apparently novel in the

Euler-Lagrange models with complex currents of three-phase electrical machines and observability issues

Basic, Duro; Malrait, Francois; Rouchon, Pierre
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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A new Lagrangian formulation with complex currents is developed and yields a direct and simple method for modeling three-phase permanent-magnet and induction machines. The Lagrangian is the sum a mechanical one and of a magnetic one. This magnetic Lagrangian is expressed in terms of rotor angle, complex stator and rotor currents. A complexification procedure widely used in quantum electrodynamic is applied here in order to derive the Euler-Lagrange equations with complex stator and rotor currents. Such complexification process avoids the usual separation into real and imaginary parts and simplifies notably the calculations. Via simple modifications of such magnetic Lagrangians we derive new dynamical models describing permanent-magnet machines with both saturation and saliency, and induction machines with both magnetic saturation and space harmonics. For each model we also provide its Hamiltonian thus its magnetic energy. This energy is also expressed with complex currents and can be directly used in Lyapunov and/or passivity based control. Further, we briefly investigate the observability of this class of Euler-Lagrange models, in the so-called sensorless case when the measured output is the stator current and the load torque is constant but unknown. For all the dynamical models obtained via such variational principles...

Covering Numbers for Support Vector Machines

Guo, Ying; Bartlett, Peter; Shawe-Taylor, John; Williamson, Robert
Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc) Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)
Tipo: Artigo de Revista Científica
Português
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Support vector (SV) machines are linear classifiers that use the maximum margin hyperplane in a feature space defined by a kernel function. Until recently, the only bounds on the generalization performance of SV machines (within Valiant's probably approximated correct framework) took no account of the kernel used except in its effect on the margin and radius. More recently, it has been shown that one can bound the relevant covering numbers using tools from functional analysis. In this paper, we show that the resulting bound can be greatly simplified. The new bound involves the eigenvalues of the integral operator induced by the kernel. It shows that the effective dimension depends on the rate of decay of these eigenvalues. We present an explicit calculation of covering numbers for an SV machine using a Gaussian kernel, which is significantly better than that implied by previous results.