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“TEMOS O DESTINO QUE MERECEMOS.
O NOSSO DESTINO ESTA DE
ACORDO COM OS NOSSOS MERITOS”
ALBERT EINSTEIN.
Imagination is more important than knowledge, for knowledge is limited while imagination embraces the entire world.
EL FUTURO SE CONSTRUYE HOY,EL SUCESSO NO ES FRUTO DE LA CASUALIDAD,SE HUMILDE ,APRENDE SIEMPRE CADA DIA.
AUTOR DO BLOG ENG.ARMANDO CAVERO MIRANDA SÃO PAULO BRASIL
"OBRIGADO DEUS PELA VIDA,PELA MINHA FAMILIA,PELO TRABALHO,PELO PÃO DE CADA DIA,PROTEGENOS DO MAL"
“SE SEUS PROJETOS FOREM PARA UM ANO,SEMEIE O GRÂO.SE FOREM PARA DEZ ANOS,PLANTE UMA ÁRVORE.SE FOREM PARA CEM ANOS,EDUQUE O POVO.”
“Sixty years ago I knew everything; now I know nothing; education is a progressive discovery of our own ignorance.
Will Durant”
Abstract)
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.
*
INTRODUCTION
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.
Power Electronics: A New Beginning By Slobodan Ćuk, TESLAco
Power Electronics progress depends on the progress in its two constituent areas: System Technology and Power Management Technology, which had been traditionally developed in the past in companies specializing in either one or the other area of expertise. System Technology companies, or Power Supply companies relied heavily on the use of the components (switches, drive and control circuits) developed by Power Management companies.
The System Technology popularly known as converter topologies has changed very little in last 50 years and is, in fact, the key reason why the Power Electronics as whole has progressed much less despite the tremendous advances made by Power Management companies in developing the new switching devices with ever increasing switching devices power and speed improvements and high performance digital control circuits.
The conventional topologies are analyzed and the sources of their deficiencies are established. This, in turns, leads to the new switching methods and the corresponding novel switching converter topologies which are overcoming all these deficiencies. However, no incremental change will do, but a fresh new look is needed. Hence what is needed is: Power Electronics: A New Beginning!
Dr. Slobodan Ćuk
Dr. Ćuk received his bachelor degree from Belgrade University, Yugoslavia, 1970, MSEE degree from University of Santa Clara, USA 1974 and her Ph.D. from Caltech, California , USA, 1976.
Dr. Ćuk was the full-time Professor of Electrical Engineering at the California Institute of Technology until January 1, 2000 where he conducted research and taught courses in Power Electronics and Fundamentals of Energy Processing. During his 25 years at Caltech, more than 35 students obtained Ph.D. degree in Power Electronics under his guidance. More than dozen of his former students are Professors of Power Electronics in U.S. and abroad while others are leading researchers in the industry.
For the invention of Integrated Magnetics Dr. Ćuk obtained a 1991 Edward Longstreth Medal from Franklin Institute which was for the first time in its 100 years history awarded to researchers in Power Electronics. His publications include over 100 scientific papers in the Power Electronics field and a three-volume book on Switched-Mode Power Conversion.
Over a span of 20 years, Dr. Ćuk has taught a number of public and in-house courses in United States, Europe and Far East, which were attended by over 4,000 Power Electronics specialists. In 1979, Dr. Ćuk founded TESLAco. He holds over 20 patents in switching power conversion filed. Over dozen patents on Ćuk Optimum Power Conversion technology are pending or are currently in preparation.
Dr. Ćuk’s Inventions and Discoveries
1. Optimum Topology Converter, known as the ĆUKconverter (1974)
2. Coupled-Inductor and Integrated Magnetics method (1975)
3. State-space averaging method (1975)
4. TESLAconverter (2000)
5. Hybrid-switching and Storageless-Switching Method (2009)
6. New DC-DC and Bridgeless AC-DC converter topologies (2010):
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.
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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.
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..
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: http://coral.ufsm.br/cograca/eletro12
LINK ALTERNATIVO https://copy.com/JEd3vsLmNYRfGiLp
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:
LINK1 http://coral.ufsm.br/cograca/livro.htm
LINK2 http://coral.ufsm.br/cograca/
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
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
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 http://hockicko.uniza.sk/Books/emft_exercises.pdf
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 ORIGINAL http://conservancy.umn.edu/handle/11299/157756
LINK FULL PAPER http://conservancy.umn.edu/bitstream/handle/11299/157756/Castelino_umn_0130E_14251.pdf?sequence=1&isAllowed=y
