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An integrated test bench for research, study or demonstration of variable speed drives of induction motors

Teixeira, H.; Leite, V.; Batista, José; Araújo, R.; Freitas, D.
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.17%
This paper presents an integrated and low cost test bench for teaching and R&D purposes in variable speed drives of induction motors. The test bench is composed by different integrated sub-systems and the resulting platform is suitable for control, parameter estimation and condition monitoring of induction machines controlled by electrical drives

Fault-Tolerant Permanent Magnet Synchronous Generator Drives for Wind Turbine Applications

Freire, Nuno Miguel Amaral
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
46.21%
This thesis intends to present new solutions for extending the reliability and availability levels of wind energy conversion systems based on permanent magnet synchronous generator (PMSG) drives. Therefore, fault-tolerant power converters for PMSG drives with the ability to handle open-circuit faults and current sensor faults are developed and proposed. By considering distinct control strategies, diagnostic techniques and converter topologies for post-fault operation, a wide range of solutions for fault-tolerant PMSG drive can be adopted with the contribution of this work. Firstly, taking into account that a standard PMSG drive is composed of two power converters in a back-to-back topology, four of the most broadly adopted control strategies for each converter are addressed in detail and their normal and faulty operation is analyzed by means of simulation and experimental results, permitting to verify the merits of each strategy under normal operation and to evaluate the fault impact. Having recognized that currents and reference voltages are suitable quantities to perform fault diagnosis, current- and voltage-based approaches are proposed in a total of six algorithms for open-circuit fault diagnosis and one algorithm for current sensor fault diagnosis. These techniques demonstrate high effectiveness and robustness...

Comparison Between Voltage Control Structures of Synchronous Machines

MOTA, D. S.; GOLDEMBERG, C.
Fonte: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC Publicador: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.15%
This paper compares the behaviour of two different control structures of automatic voltage regulators of synchronous machines equipped with static excitation systems. These systems have a fully controlled thyristor bridge that supplies DC current to the rotor winding. The rectifier bridge is fed by the stator terminals through a step-down transformer. The first control structure, named ""Direct Control"", has a single proportional-integral (PI) regulator that compares stator voltage setpoint with measured voltage and acts directly on the thyristor bridge`s firing angle. This control structure is usually employed in commercial excitation systems for hydrogenerators. The second structure, named ""Cascade Control"", was inspired on control loops of commercial DC motor drives. Such drives employ two PIs in a cascade arrangement, the external PI deals with the motor speed while the internal one regulates the armature current. In the adaptation proposed, the external PI compares setpoint with the actual stator voltage and produces the setpoint to the internal PI-loop which controls the field current.

Electromagnetic torque ripple and copper losses reduction in permanent magnet synchronous machines

Monteiro, José Roberto Boffino de Almeida; Oliveira Junior, Azauri Albano de; Aguiar, Manoel Luis de; Sanagiotti, Edmilson Rogerio
Fonte: WILEY-BLACKWELL; HOBOKEN Publicador: WILEY-BLACKWELL; HOBOKEN
Tipo: Artigo de Revista Científica
Português
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36.23%
This paper presents a method for electromagnetic torque ripple and copper losses reduction in (non-sinusoidal or trapezoidal) surface-mount permanent magnet synchronous machines (SM-PMSM). The method is based on an extension of classical dq transformation that makes it possible to write a vectorial model for this kind of machine (with a non-sinusoidal back-EMF waveform). This model is obtained by the application of that transformation in the classical machine per-phase model. That transformation can be applied to machines that have any type of back-EMF waveform, and not only trapezoidal or square-wave back-EMF waveforms. Implementation results are shown for an electrical converter, using the proposed vectorial model, feeding a non-sinusoidal synchronous machine (brushless DC motor). They show that the use of this vectorial mode is a way to achieve improvements in the performance of this kind of machine, considering the electromagnetic torque ripple and copper losses, if compared to a drive system that employs a classical six-step mode as a converter. Copyright (C) 2011 John Wiley & Sons, Ltd.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); "Conselho Nacional de Desenvolvimento Cientifico e Tecnologico" (CNPq); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)

Speed Neuro-fuzzy Estimator Applied To Sensorless Induction Motor Control

Lima, F.; Kaiser, Walter; Silva, Ivan Nunes da; Oliveira Junior, Azauri Albano de
Fonte: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC; PISCATAWAY Publicador: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC; PISCATAWAY
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.31%
This work proposes the development of an Adaptive Neuro-fuzzy Inference System (ANFIS) estimator applied to speed control in a three-phase induction motor sensorless drive. Usually, ANFIS is used to replace the traditional PI controller in induction motor drives. The evaluation of the estimation capability of the ANFIS in a sensorless drive is one of the contributions of this work. The ANFIS speed estimator is validated in a magnetizing flux oriented control scheme, consisting in one more contribution. As an open-loop estimator, it is applied to moderate performance drives and it is not the proposal of this work to solve the low and zero speed estimation problems. Simulations to evaluate the performance of the estimator considering the vector drive system were done from the Matlab/Simulink(R) software. To determine the benefits of the proposed model, a practical system was implemented using a voltage source inverter (VSI) to drive the motor and the vector control including the ANFIS estimator, which is carried out by the Real Time Toolbox from Matlab/Simulink(R) software and a data acquisition card from National Instruments.

Análise de desempenho de redes de comunicação industrial em acionamentos de motores elétricos trifásicos; Performance analysis of industrial communication networks in electrical motors drives

Dias, André Luís
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 09/12/2014 Português
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Este trabalho propõe analisar o desempenho de redes de comunicação industrial em aplicações de acionamentos de motores elétricos trifásicos. Compara-se o desempenho da tecnologia Profibus DP em relação à Profinet. O desempenho é verificado a partir de especificações técnicas de ambos protocolos e experimentos práticos para coleta de dados e análise dos seguintes indicadores de desempenho: tempo de ciclo, jitter e ocupação de largura de banda. Adicionalmente, é verificado o desempenho de uma aplicação de controle de posição, utilizando estes protocolos na malha de controle, através do tempo de acomodação do sistema. Conclusões mostram que a rede Profibus DPV0 é a mais rápida quando possui menos dispositivos, porém o Profinet RT consegue manter baixos valores de tempo de ciclo mesmo com grande quantidade de dispositivos e possui maior determinismo na topologia em barramento. No que diz respeito ao controle de posição estudado, as tecnologias apresentam desempenho similar para tempo de acomodação do sistema, porém o Profinet IRT foi o mais determinístico.; This work proposes a performance analysis of industrial communication networks in applications of electric AC motor drives. It compares the performance of Profibus DP technology in relation to Profinet. Performance is verified from technical specifications of both protocols and practical experiments for data collection and analysis of the following performance indicators: cycle time...

A simplified method for determining the high frequency induction motor equivalent electrical circuit parameters to be used in EMI effect

Riehl, Rudolf Ribeiro; Ruppert Filho, Ernesto
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 1244-1248
Português
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36.36%
The aim of this paper is to present a simple method for determining the high frequency parameters of a three-phase induction motor to be used in studies involving variable speed drives with PWM three-phase inverters, in which it is necessary to check the effects caused to the motor by the electromagnetic interference, (EMI) in the differential mode, as well as in the common mode. The motor parameters determination is generally performed in adequate laboratories using accurate instruments, such as very expensive RLC bridges. The method proposed here consists in the identification of the motor equivalent electrical circuit parameters in rated frequency and in high frequency through characteristic tests in the laboratory, together with the use of characteristic equations and curves, shown in the references to be mentioned for determining the motor high frequency parasite capacitances and also through system simulations using dedicated software, like Pspice, determining the characteristic waveforms involved in the differential and common mode phenomena, comparing and validating the procedure through published papers [01].

Testing and simulation of fractionary electromechanical rotative drives

Burgoa,D. P.; Martin,C. A.
Fonte: The Brazilian Society of Mechanical Sciences Publicador: The Brazilian Society of Mechanical Sciences
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2002 Português
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This paper concerns the development of drives that use electromechanical rotative motor systems. It is proposed an experimental drive test structure integrated to simulation softwares. The objective of this work is to show that an affordable model validation procedure can be obtained by combining a precision data acquisition with well tuned state-of-the-art simulation packages. This is required for fitting, in the best way, a drive to its load or, inversely, to adapt loads to given drive characteristics.

Optimal-efficiency constant-speed control of nonlinear variable reluctance motor drives

Torrey, David Allan
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 2 v. ([1], 362 leaves); 23339562 bytes; 23339322 bytes; application/pdf; application/pdf
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by David Allan Torrey.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.; Bibliography: v. 2, leaves 359-362.

Electron Bernstein wave current drive modeling in toroidal plasma confinement

Decker, Joan, 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 340 p.; 14541425 bytes; 14556444 bytes; application/pdf; application/pdf
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The steady-state confinement of tokamak plasmas in a fusion reactor requires non-inductively driven toroidal currents. Radio frequency waves in the electron cyclotron (EC) range of frequencies can drive localized currents and are thus particularly attractive for control of the current profile. In the high-[beta] regimes of spherical tokamaks (ST) such as NSTX and MAST, heating and current drive (CD) by conventional electron cyclotron waves is not possible. However, electron Bernstein waves (EBW) have been proposed as an alternative for CD in these overdense devices. Given the important role predicted for CD by EBWs in high-[beta] STs, a detailed study of EBWCD must be undertaken. In this thesis a systematic analysis of EBWCD is provided. In particular, the characteristics of EBWs, the physics of resonant wave-particle interaction, and the CD mechanisms are investigated in detail. The CD efficiency and the current deposition profile are calculated using the numerical code DKE, which solve the drift-kinetic equation. Two scenarios for EBWCD are identified. The first scenario consists of approaching a harmonic of the EC resonance from a lower B-field region and drives current in the plasma core using the Fisch-Boozer mechanism.; (cont.) The other scenario consists of approaching a harmonic of the EC resonance from a higher B-field region and drives current off-axis on the outboard side using the Ohkawa mechanism. Both schemes drive current in the toroidal direction opposite to the parallel wave vector. The EBWCI) efficiency is found to be higher than ECCD efficiency because the EBW power is deposited in the tail of the electron distribution function. The results of this thesis confirm the important role of EBWs for driving currents in high-[beta] plasmas. The analytical and numerical tools developed as part of this thesis can be used to design...

Minimally intrusive strategies for fault detection and energy monitoring

Cox, Robert Williams, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 215 p.
Português
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This thesis addresses the need for automated monitoring systems that rely on minimally intrusive sensor arrays. The monitoring techniques employed in this thesis require fewer sensors because they take a different approach to the measurement problem. Specifically, these techniques use the power distribution network in the target system as a power source, a sensor array, and a communications channel. In this "multi-use" approach, the only measurement sources are a set of centrally located electrical transducers (i.e. voltage and current sensors) and a set of remotely located sensors that communicate with a central processing unit via power line modems. In general, these systems determine the status of critical loads or systems using only electrical data. Thus, remotely located sensors are only employed in order to gather information that would be difficult, if not impossible, to obtain electrically. Examples of such quantities include air exchange rates and occupancy levels in individual rooms. This thesis describes the development and application of several critical features of the minimally intrusive monitoring systems described above. First, it presents several model-based methods that make it possible to use electrical data to detect faults in certain mechanical systems.; (cont.) In particular...

On the use of NAND flash memory in high-performance relational databases

Myers, Daniel (Daniel Sumers)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 49 p.
Português
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High-density NAND flash storage has become relatively inexpensive due to the popularity of various consumer electronics. Recently, several manufacturers have released IDE-compatible NAND flash-based drives in sizes up to 64 GB at reasonable (sub-$1000) prices. Because flash is significantly more durable than mechanical hard drives and requires considerably less energy, there is some speculation that large data centers will adopt these devices. As database workloads make up a substantial fraction of the processing done by data centers, it is interesting to ask how switching to flash-based storage will affect the performance of database systems. We evaluate this question using IDE-based flash drives from two major manufacturers. We measure their read and write performance and find that flash has excellent random read performance, acceptable sequential read performance, and quite poor write performance compared to conventional IDE disks. We then consider how standard database algorithms are affected by these performance characteristics and find that the fast random read capability dramatically improves the performance of secondary indexes and index-based join algorithms. We next investigate using logstructured filesystems to mitigate the poor write performance of flash and find an 8.2x improvement in random write performance...

High robustness and reliability of fuzzy logic based position estimation for sensorless switched reluctance motor drives

Cheok, A.; Ertugrul, N.
Fonte: IEEE-Inst Electrical Electronics Engineers Inc Publicador: IEEE-Inst Electrical Electronics Engineers Inc
Tipo: Artigo de Revista Científica
Publicado em //2000 Português
Relevância na Pesquisa
36.17%
In many applications where motor drives are used, concern. Thus, a major consideration is the reliability of position estimation schemes when sensor less SR motor drive control is employed. Hence, in this paper, the robust of a fuzzy logic based angle estimation algorithm for the switched reluctance motor (SR) motor is described. It is shown using theoretical analysis and experimental results, that by using logic, the angle estimation scheme gains a high level of robustness and reliability. A theoretical and quantitative analysis of the noise and error commonly found in practical motor drives is given, and how this can affect SR motor position estimation. An analysis is also given on the concepts of robustness and reliability. It is shown that the fuzzy logic based scheme is robust to erroneous and noisy signals commonly found in motor drives.; Adrian David Cheok and Nesimi Ertugrul; Copyright © 2000 IEEE

Sensorless position estimation in fault-tolerant permanent magnet AC motor drives with redundancy.

An, Jae Sam
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2010 Português
Relevância na Pesquisa
36.24%
Safety critical applications are heavily dependent on fault-tolerant motor drives being capable of continuing to operate satisfactorily under faults. This research utilizes a fault-tolerant PMAC motor drive with redundancy involving dual drives to provide parallel redundancy where each drive has electrically, magnetically, thermally and physically independent phases to improve its fault-tolerant capabilities. PMAC motor drives can offer high power and torque densities which are essential in high performance applications, for example, more-electric airplanes. In this thesis, two sensorless algorithms are proposed to estimate the rotor position in a fault-tolerant three-phase surface-mounted sinusoidal PMAC motor drive with redundancy under normal and faulted operating conditions. The key aims are to improve the reliability by eliminating the use of a position sensor which is one of major sources of failures, as well as by offering fault-tolerant position estimation. The algorithms utilize measurements of the winding currents and phase voltages, to compute flux linkage increments without integration, hence producing the predicted position values. Estimation errors due measurements are compensated for by a modified phase-locked loop technique which forces the predicted positions to track the flux linkage increments...

Cost benefit analysis of adjustable speed drives aboard Arleigh Burke class destroyers

Weekes, Godfrey D.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado
Português
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36.23%
Approved for public release; distribution is unlimited; As the U.S. Navy seeks new and innovative ways to maximize its return from a finite budget, an evaluation of its operational practices must be done. Electrical power consumption and fuel efficiency are major factors in the Total Operating Cost (TOC) of naval ships and systems. An evaluation of an alternative mean for delivering electrical power to motors and pumps was conducted with the understanding that principles of the findings could be applied to fans as well. Adjustable Speed Drives (ASD), AC induction motors, AC synchronous motors, centrifugal pumps, and positive displacement pumps were examined. The technical challenges associated with ASDs were explored. MATLAB was used to calculate the potential power savings to be gained by introducing ASD technology to the Firemain and Chilled Water Systems. MATLAB was also used to calculate fuel cost savings from reduced consumption of Shipboard power.

Fault Tolerant Multiphase Electrical Drives: The Impact of Design

SEMAIL, Eric; KESTELYN, Xavier; LOCMENT, Fabrice
Fonte: EDP Sciences Publicador: EDP Sciences
Português
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La version editeur de cet article est disponible à l'adresse suivante : http://journals.cambridge.org/action//displayFulltext?type=1&fid=8024174&jid=JAP&volumeId=43&issueId=02&aid=8024172&bodyId=&membershipNumber=&societyETOCSession=; This paper deals with fault tolerant multiphase electrical drives. The quality of the torque of a vector-controlled Permanent Magnet (PM) Synchronous Machine supplied by a multi-leg Voltage Source Inverter (VSI) is examined in normal operation and when one or two phases are open-circuited. It is then deduced that a seven-phase machine is a good compromise allowing high torque-to-volume density and easy control with smooth torque in fault operation. Experimental results confirm the predicted characteristics.

An On-line Method for Stator Fault Detection in Multi-phase PMSM Drives

MEINGUET, Fabien; SEMAIL, Eric; GYSELINCK, Johan
Fonte: IEEE - Institute of Electrical and Electronics Engineers Publicador: IEEE - Institute of Electrical and Electronics Engineers
Português
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46.11%
This paper deals with an on-line fault detection method for multi-phase PMSM drives. The method is based on the detection of the stator current positive- and negative sequence fundamental components expressed in the stationary αβ reference frame. These components allow calculating a fault index used for the detection of stator faults, such as open-circuit faults. The decision criterion is based on the CUSUM algorithm. A model of a five-phase machine with one single-phase open-circuit is derived and validated with experimental results. Then, it is shown that the proposed method achieves fault detection on a wide speed range and even during speed transient.

Signal-based Technique for Fault Detection and Isolation of Inverter Faults in Multi-phase Drives

MEINGUET, Fabien; SANDULESCU, Paul; ASLAN, Bassel; LU, Li; NGUYEN, Ngac Ky; KESTELYN, Xavier; SEMAIL, Eric
Fonte: IEEE - Institute of Electrical and Electronics Engineers Publicador: IEEE - Institute of Electrical and Electronics Engineers
Português
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46.11%
A method for fault detection and isolation is proposed and applied to inverter faults in multi-phase drives. An analysis of simulations in faulty conditions leads to the derivation of suitable fault indices. These are based on the unbalance of the phase currents and their instantaneous frequency. The method is applied to a five-phase permanent-magnet synchronous machine drive. Simulations and experiments validate the proposed method.; Projet SOFRACI

Vibration-to-electric energy conversion using a mechanically-varied capacitor

Yen, Bernard Chih-Hsun, 1981-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 133 p.; 6333179 bytes; 6350559 bytes; application/pdf; application/pdf
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Past research in vibration energy harvesting has focused on the use of variable capacitors, magnets, or piezoelectric materials as the basis of energy transduction. How- ever, few of these studies have explored the detailed circuits required to make the energy harvesting work. In contrast, this thesis develops and demonstrates a circuit to support variable-capacitor-based energy harvesting. The circuit combines a diode-based charge pump with an asynchronous inductive flyback mechanism to re- turn the pumped energy to a central reservoir. A cantilever beam variable capacitor with 650 pF DC capacitance and 347.77 pF zero-to-peak AC capacitance, formed by a 43.56 cm2 spring steel top plate attached to an aluminum base, drives the experimental charge pump near 1.56 kHz. HSPICE simulation confirms that given a maximum to minimum capacitance ratio larger than 1.65 and realistic models for the transistor and diodes, the circuit can harvest approximately 1 lW of power. This power level is achieved after optimizing the flyback path to run at approximately 1/4 of the mechanical vibration frequency with a duty ratio of 0.0019. Simulation also shows that unless a source-referenced clock drives the MOSFET, spurious energy injection can occur, which would inflate the circuit's conversion efficiency if the harvester is driven by an external clock. A working vibration energy harvester comprising a time varying capacitor with a capacitance ratio of 3.27 converted sufficient energy to sustain 6 V across a 20 MQ load.; (cont.) This translates to an average power of 1.8 pW. Based on a theoretical harvesting limit of 40.67 luW...

Design principles and patterns for computer systems that are simultaneously secure and usable

Garfinkel, Simson
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 472 p.; 29543936 bytes; 31405031 bytes; application/pdf; application/pdf
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It is widely believed that security and usability are two antagonistic goals in system design. This thesis argues that there are many instances in which security and usability can be synergistically improved by revising the way that specific functionality is implemented in many of today's operating systems and applications. Specific design principles and patterns are presented that can accomplish this goal. Patterns are presented that minimize the release of confidential information through remnant and remanent data left on hard drives, in web browsers, and in documents. These patterns are based on a study involving the purchase of 236 hard drives on the secondary market, interviews conducted with organizations whose drives had been acquired, and through a detailed examination of modern web browsers and reports of information leakage in documents. Patterns are presented that enable secure messaging through the adoption of new key management techniques. These patterns are supported through an analysis of S/MIME handling in modern email clients, a survey of 469 Amazon.com merchants, and a user study of 43 individuals. Patterns are presented for promoting secure operation and for reducing the danger of covert monitoring. These patterns are supported by the literature review and an analysis of current systems.; (cont.) In every case considered...