sábado, 26 de dezembro de 2015
A Novel Single-Phase Cascaded Multilevel AC-AC Converter Without Commutation Problem Kim, Sang-hun Department of Electrical Engineering Graduate School, Kyungpook National University Daegu, Korea
This paper presents a novel cascaded multilevel PWM ac-ac converter that can solve commutation problem. By cascading the single-phase PWM ac-ac converter that uses basic switching cell structure and coupled inductors, the proposed converter does not need to sense the voltage or current polarity for safe commutation. When many unit-cells are cascaded, the proposed converter has more output voltage levels and can obtain high ac output voltage by using low voltage rating switching devices. By applying phase-shifted PWM technique, the proposed converter can reduce output filter size significantly. A 2 kW prototype converter having four unit-cell structure is built and tested to verify the performance. *
quinta-feira, 24 de dezembro de 2015
A VOLTAGE SAG SUPPORTER UTILIZING A PWM-SWITCHED AUTOTRANSFORMER A Thesis Presented to The Academic Faculty by Dong-Myung Lee School of Electrical & Computer Engineering Georgia Institute of Technology Atlanta
1.1 Background A power distribution system is similar to a vast network of rivers. It is important to remove any system faults so that the rest of the power distribution service is not interrupted or damaged. When a fault occurs somewhere in a power distribution system, the voltage is affected throughout the power system. Among various power quality problems, the majority of events are associated with either a voltage sag or a voltage swell, and they often cause serious power interruptions. A voltage sag condition implies that the voltage on one or more phases drops below the specified tolerance for a short period of time. A voltage swell condition occurs when the voltage of one or more phases rises above the specified tolerance for a short period of time. The causes of voltage sags and swells are associated with faults within the power distribution system. Users located a close distance to the fault experience voltage sags much greater in magnitude and duration than users located farther away, and as the power distribution system have power interruptions during a fault because of the effects of a voltage sag or voltage swell produced in the system by the fault. The objective of this research is to develop a novel voltage control scheme that can compensate for voltage sag and swell conditions in three-phase power systems.
segunda-feira, 21 de dezembro de 2015
domingo, 6 de dezembro de 2015
sábado, 5 de dezembro de 2015
quarta-feira, 2 de dezembro de 2015
sexta-feira, 13 de novembro de 2015
quinta-feira, 12 de novembro de 2015
A study on Auto Transformer protective method for AC electric railway system.
Son, Dong-Shic Department of Railroad Engineering The Graduate School of Green Railroad Woosong University
An AC electric railway uses AT(auto transformer), BT(Booster Transformer), and direct power feeding system. Today, as a result of an increase in use of load current system, AT feeding system has became a mostly and widely used system due to its profitability in high and long-distance power feeding and inductive interference. AT is a core facility of the AC electric railway, a major public transportation, in AT traction power feeding system thus, the suspension of train operation due to the malfunction of AT feeding system would causes not only a high volume of civil petitions but also an interruption to the power supply to the train that could bring a second incident. In general, the power transformer protection is classified into electronic protection that includes differential protection (87T), over current protection (50/51), and earth fault protection (50/51N), and the mechanical protection such as buchholz relay, sudden pressure relay, winding temperature indicator, temperature indicator for insulation oil however, the failure in the operation of AT is protected only by an alarm signal controlled by substation using current and impedance relay. Therefore, to prevent the failure in mechanical protection, sectioning post(SP), sub-sectioning post(SSP), and parallel post(PP) needs to be protected by electronic protection as well as mechanical protection. In addition, accidents related to AT traction power supply system are divided into an outside (on railroad) accident mostly occurred due to traction line earth(T-R earth), feeding line earth(F-R earth), sectioning line earth(F-R earth), and short circuit(T-R short circuit) between feeding and sectioning linen, and an inside (at substation) accident mostly occurred due to earth and short circuit of AT winding furthermore, no matter what type of accident related to AT traction power supply system occurs it is protected by over current or impedance relay from substation Even though the AT related accidents could result in the discontinuation of rail service due to an inability to separate the feeder section, it is difficult to find whether the type of accident is outside or inside. As a result, it unnecessarily costs long time to deal with the accident because of unclearness of the cause.
segunda-feira, 9 de novembro de 2015
ESTUDIE INGENIERIA ELECTRONICA CON ESTE LIBRO ES UN GRANDE CLASICO
ENCONTRADO EN LA WEB CON ACCESO LIBRE EN LOS SIGUIENTES LINKS:
LINK ORIGINAL EN LA WEB
LINK DIRECTO PARA BAJAR EN FORMATO PDF
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AGRADEÇO A COLABORAÇAO DO ENG, JORGE MIREZ DE LA UNI -PERU
domingo, 8 de novembro de 2015
CALCULO Y ANALISIS DE REGIMENES DE TRABAJO DE REDES ELECTRICAS -VENIKOV,ANISOVA,FOKIN-Расчеты и анализ режимов работы сетей -Веников В.А.,Фокин, Анисова,Федоров
LINK BOOK RUSSIAN VERSION
Electrical network performance calculations and analysis / General editor V. A. Venikov [and others] ; translated from the Russian by O.B. Volodina. - Rev. from the 1974 Russian edition.
Moscow : Mir Publishers,
quinta-feira, 5 de novembro de 2015
domingo, 1 de novembro de 2015
Fundamentos de la teoría de circuitos Popov VP - Основы теории цепей Попов В.П.
El libro corresponde al programa del curso "Fundamentos de la teoría de circuitos." Establece la teoría de circuitos eléctricos lineales con parámetros concentrados y distribuidos en condiciones de estado estacionario y transitorio; Se presta mucha atención al análisis de los fundamentos de circuitos no lineales resistivas, conceptos de matriz topológica, la teoría de grafos, los métodos de la máquina de formación de ecuaciones de equilibrio eléctricos, análisis de circuitos con fuentes controladas.
LINK ORIGINAL EN LAWEB FORMATO DJVU
quarta-feira, 28 de outubro de 2015
Development of Three-phase On-Board Battery Charger for PHEV ( plug-in hybrid electrical vehicle ) without High-Capacity Electrolytic Capacitor Graduate School, Myongji University Department of Electrical Engineering ZHANG YINGHAO
Development of Three-Phase On-Board Battery Charger for PHEV without High-Capacity Electrolytic Capacitor Ying-hao, Zhang Department of Electrical Engineering Graduate School, Myongji University Advisor Professor Byung-Moon Han
A new two-stage on-board battery charger which can operate in both three-phase mode and single-mode is proposed for plug-in hybrid electric vehicles (PHEVs). It consists of three identical chargers which connect to battery in parallel, and each of them has a cascaded structure of high frequency resonant converter with a constant switching frequency for electrical isolation, and buck-boost converter for charging control and harmonic regulation of input current under wide range line-input voltage. This structure uses small link capacitors so that high-capacity electrolytic capacitors can be removed in automotive applications. An LLC resonant converter is proposed in the first stage. The parallel buck-boost converters operating in discontinuous conduction mode are employed in the second stage, so that the voltage stress of components could be reduced and the simple controller can be used to control charging current. Digital control of converter is realized by applying DSP (Digital Signal Processor) that performs constant current through duty control of buck-boost converter. Duty ratio of LLC converter is unregulated. Proposed Converter stably operates in various load condition (within 10kW) and it is proven that the proposed converter achieves efficiency of higher than 93% and power factor of higher than 0.99 through experiment..
domingo, 25 de outubro de 2015
quinta-feira, 22 de outubro de 2015
sábado, 17 de outubro de 2015
ELECTROMAGNETISMO - CLAUDIO GRAÇA-CURSO DE ENGENHARIA MECANICA UNIVERSIDADE FEDERAL DE SANTA MARIA BRASIL
HOJE SURFANDO NA WEB ENCONTRE ESTE INTERESANTE LIVRO EM PORTUGUES DO PROFESSOR CLAUDIO GRAÇA DA UNIVERSIDADE FEDERAL DE SANTA MARIA NA
SIGUENTE PAGINA WEB PODEM CONFERIR:
AGRADECIMENTO ESPECIAL AO PROFESSOR CLAUDIO GRAÇA Curso de Engenharia Mecânica POR DISPONIBILIZAR LIVREMENTE ESTE LIVRO EN SUA PAGINA NA WEB,ELE ESTA REALIZANDO UM PROJETO DE ENSINO A CURTA DISTANCIA DE FISICA PODEM CONFERIR ESTE GRANDIOSO PROJETO NAS PAGINAS WEB SIGUENTES:
COLEÇÃO DE PROVAS ENG04074 - Teoria de Circuitos I - Universidade Federal do Rio Grande do Sul Escola de Engenharia Departamento de Engenharia Elétrica-BRASIL
1. IDENTIFICAÇÃO. Nome do Departamento: DELET - DEPARTAMENTO DE ENGENHARIA ELÉTRICA (http://www.ufrgs.br/delet/) Nome da Atividade de Ensino: - ENG04074 - TEORIA DE CIRCUITOS I Cursos(s) de Oferecimento: - ENGENHARIA ELÉTRICA Caráter: - Obrigatória Pré-requisitos por Curso: FIS01182 – FÍSICA GERAL - ELETROMAGNETISMO MAT01354 – CÁLCULO E GEOMETRIA ANALÍTICA II-A
LINK ORIGINAL COM TODAS AS PROVAS
EEL420 - Circuitos Elétricos I - Engenharia Biomédica UFRJ - UNIVERSIDADE FEDERAL DE RIO DE JANEIRO BRASIL
COLEÇÃO DE PROVAS CIRCUITOS ELETRICOS EEL420
Provas Anteriores-EXAMENES ANTERIORES
2007/2, 2008/1, 2008/2, 2009/1, 2011/2, 2012/2, 2014/1,2014/2 e 2015/1.
LINK ORIGINAL DE ENGENHARIA BIOMEDICA
quarta-feira, 14 de outubro de 2015
Design stable analog and digital power supplies in minutes!
Stabilising a power supply using WDS could not be simpler. The user simply selects their topology and types in their input/output specification into WDS. The software will then automatically select the appropriate component values for this design. At any stage the user can change the component values away from those automatically calculated by WDS and enter the actual component value used in their design. From power stage component selection to poles, zeros and controller coefficients; our advanced PSU design software, WDS, will greatly simplify the task of designing a power supply whilst still keeping you in control at every stage of the process. WDS has been designed as the ultimate toolbox for the power supply design engineer. Designs and stabilises analog and digital PSU control loops in minutes Automatically calculates poles and zeros as well as component values of the worlds most popular topologies Sophisticated control algorithms stabilise digital power supplies with automatic coefficient calculations for floating point, 32 bit and 16 bit processors Special features allow manipulation of digital compensator coefficients for a host of micro-controllers Automatic compensator design for isolated power supplies with TLx431/LMx431 and a host of industry standard optocouplers Simulations in time domain, frequency domain and ability to superimpose real measurements on simulated data
NAVEGANDO HOJE ENCONTRE NA WEB ESTE INTERESANTE LIVRO DE TEORIA DO ELECTROMAGNETISMO DO PROF. KLEBER MACHADO
PAGINA WEB ORIGINAL NA WEB
terça-feira, 13 de outubro de 2015
DEMO BOOK GOOGLE
ELECTROMAGNETIC FIELD THEORY EXERCISES Tobia Carozzi Anders Eriksson Bengt Lundborg Bo Thidé Mattias Waldenvik Department of Space and Plasma Physics Uppsala University
ELECTROMAGNETIC FIELD THEORY EXERCISIES
Tobia Carozzi Anders Eriksson Bengt Lundborg Bo Thidé Mattias Waldenvik Department of Space and Plasma Physics Uppsala University and Swedish Institute of Space Physics Uppsala Division Sweden
LINK ORIGINAL EN LA WEB
sábado, 10 de outubro de 2015
Power electronic transformers for AC-AC and AC-DC conversion with reduced number of switches Castelino, Gysler Fatima (2013)
Autor Castelino, Gysler Fatima Data 2013-08
Type Thesis or Dissertation
Resumo In this research, a novel reduced-switch Power Electronic Transformer is proposed for three-phase power conversion (three-phase AC to AC as well as three-phase AC to DC). The goal of this project is to reduce the weight and size of the power converter by replacing the low-frequency transformers with high-frequency transformers (HFTs). The novelty of these proposed topologies is that they have only two controlled switches on the primary side of the high-frequency transformers. Additionally, these switches operate at 50% duty ratio, hence they are easy to control. Pulse Width Modulation (PWM) control is only necessary in the converters on the secondary side of the HFT. The modulation strategies proposed in this work achieve nearly Zero Current Switching (ZCS) for these two primary switches. In the proposed three-phase AC to AC Power Electronic Transformer, a Matrix Converter (MC) is employed on the secondary side of the transformer. Matrix converter with nine four-quadrant switches is a `more-silicon' and nearly capacitor-less solution for AC to AC conversion. This single-stage AC-AC converter without any electrolytic capacitors translates to higher reliability and efficiency. High-frequency transformers have finite leakage inductance, hence, any switching in the primary or secondary of the transformer requires commutation of the transformer inductive currents. This problem of leakage energy commutation and the required protection are studied in detail in this thesis. Other features of this converter are bi-directional power flow and power factor correction. The second Power Electronic Transformer is proposed for three-phase AC to DC power conversion. This converter operates on the Dual Active Bridge (DAB) principle wherein the transformer leakage inductance is used for power transfer. Hence, this converter does not suffer from problems associated with leakage energy commutation and additional snubber circuits are not required for this converter. The proposed modulation provides the advantages of unity power factor on the AC side, galvanic isolation and bi-directional power flow capability. Both these PETs have been analyzed and simulated. Laboratory prototypes have been built and tested to verify the advantages of the proposed PETs.
LINK FULL PAPER