“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.”

ARRIBA SIEMPRE ARRIBA HASTA ALCANZAR LA GLORIA JORGE CHAVEZ DARTNELL SEPTIEMBRE 1910


SAO PAULO BRASIL

segunda-feira, 26 de março de 2012

Emprededurismo en ciencia y tecnología. Ricardo Alcázar, director Cámara de Comercio de Lima


Enviado por memontoyaz em 25/03/2012

Emprededurismo en ciencia y tecnología
Ricardo Alcázar, director Cámara de Comercio de Lima
entrevistado por Modesto Montoya
en Encuentro con la Ciencia
Programa de Radio San Borja, los domingos a las 10:00 am

sexta-feira, 23 de março de 2012

Filtros ativos paralelos para compensação dinâmica de problemas de corrente em sistemas monofásicos e trifásicos

Este artigo apresenta resultados experimentais de um Filtro Ativo Paralelo Trifásico a 4 fios e de um Filtro Ativo Paralelo Monofásico. O filtro ativo trifásico tem a capacidade de compensar harmônicos de corrente, fator de potência e desequilíbrios de corrente.

Já o filtro ativo monofásico compensa harmônicos de corrente e fator de potência. Ambos os filtros têm o sistema de controle baseado na teoria da potência instantânea (Teoria p-q), que foi implementado num DSP, e utilizam inversores a dois níveis do tipo fonte de tensão com controle de corrente. Resultados experimentais dos filtros ativos mencionados são apresentados.

Para ver o artigo completo, acesse o seguinte endereço:
http://repositorium.sdum.uminho.pt/bitstream/1822/7658/3/XCLEE-07_FAP_MONO_TRI.pdf
FONTE ORIGINAL:http://qualidadedaenergia.blogspot.com.br/

quinta-feira, 22 de março de 2012

FILTER DESIGN FOR GRID CONNECTED PV INVERTERS

FILTER DESIGN FOR GRID CONNECTED PV INVERTERS
Hyosung Kim Kyoung-Hwan Kim
Kongju National University KACO Korea Inc.
School of Electrical Electronics Engineering 1st Floor, Dongbang Rental Bldg
275, Budae, Cheonan, Chungnam, 330-717 Korea 333-1, Sangdaeeon, Jungwon, Seongnam, Korea
e-mail: hyoskim@kongju.ac.kr e-mail: paul.kim@kacokorea.com

Abstract-This paper proposes filter design guideline for
single-phase grid-connected PV inverters. By analyzing the
instantaneous voltage applied on the filter inductor, the
switching ripple current through the filter inductor is
precisely calculated. Therefore, filter inductance can be
designed accurately which guaranties the switching ripple
current under the target value. Proposed filter design
method is verified by experiment.
FULL PAPER: http://www.mediafire.com/?8co1ka9so395tcr

A Harmonic Circulation Current Reduction Method for Parallel Operation of UPS with a Three-Phase PWM Inverter



A Harmonic Circulation Current Reduction Method for Parallel
Operation of UPS with a Three-Phase PWM Inverter
Kyung-Hwan Kim†, Wook-Dong Kim* and Dong-Suk Hyun**
†*EHWA Technologies and Information, Seoul, Korea
**Dept. of Electrical Eng., Hanyang University, Seoul, Korea



ABSTRACT
In a parallel operation of UPS, there are two types of circulating currents between UPS. One is the low order circulating
current with a fundamental frequency caused by the amplitude and phase differences of UPS output voltages, and the other
is the harmonic circulating current with PWM switching frequency caused by non-synchronized PWM waveforms among
UPS. The elimination of the low order circulating current is essential for optimal load sharing in parallel operations of UPS,
which can be accomplished by the phase and magnitude control at each UPS. The harmonic circulating current may cause
troubles and deteriorate in performance of the controller for optimal load sharing in parallel operation of UPS. This paper
presents a PWM synchronizing method to eliminate the harmonic circulation current in parallel operation of UPS. The
effectiveness of the proposed scheme has been investigated and verified through experiments by a 50kVA UPS.

FULL PAPER HERE:
http://www.mediafire.com/?d4zu28a1f8cm9m2

Design of Advanced Voltage Controller for Three-Phase UPS inverters by KYUNG-HWAN KIM




Design of Advanced Voltage Controller for
Three-Phase UPS inverters
by
KYUNG-HWAN KIM
Under the supervision of
Prof. DONG-SEOK HYUN, Ph.D.
Dept. of Electrical Engineering
The Graduate School of Hanyang University

Inverter system, which uses LC component as the output filter, is essential for
a UPS (Uninterruptible Power supply), UPQC (Universal Custom Power Conditioner) and PCS (Power Conditioning System) for the photovoltaic power system.

This paper presents DSP (Digital Signal Processor) controlled voltage
controller for a 3-phase UPS inverter, which is able to compensate the voltage
distortions due to unbalanced and nonlinear loads. The paper discussed the problem
of conventional control schemes for the compensation of voltage distortion when
they are applied to UPS inverter, and proposes advanced synchronous reference
frame control scheme which is able to overcome the problem. In order to solve the
problem of low damping ratio of LC filter, the inverter current feed-forward
compensator including the selection of the feed-forward gain is proposed. And the
digital filter for a compensation of the voltage distortion due to unbalanced and
nonlinear loads is also proposed, which makes PI controllers in the synchronous
reference frame are able to operate with DC values even under nonlinear and
unbalanced load, likewise ensures PI controllers are able to provide zero steady
state error.
In order to improve the practical usability of the proposed scheme in the paper,
the realization of the PLL and the parallel operation, which are essential for UPS,
using the proposed controller is also presented. Especially, this paper shows that
the feed-forward compensation of the inverter current and the PWM
synchronization method proposed in the paper ensures a high precise load-sharing
performance in parallel operation of inverter system.
The effectiveness of the proposed scheme has been investigated and verified in
digital simulation. This thesis also investigates the digital implementation of the
proposed systems and all of the related theoretical concepts and control systems
have been verified in experimental prototype of the UPS systems.

HIGH POWER FACTOR THREE PHASE UNINTERRUPTIBLE POWER SUPPLY USING THE FUEL CELL BASED AUXILIARY POWER SYSTEM JAE HYEONG







HIGH POWER FACTOR THREE PHASE UNINTERRUPTIBLE POWER SUPPLY USING THE FUEL CELL BASED
AUXILIARY POWER SYSTEM
JAE HYEONG

DEPARTAMENT OF ELECTRICAL AND COMPUTER ENGINEERING
SUNGKYUNKWAN UNIVERSITY

FULL PAPER HERE:http://www.mediafire.com/?o8bw1d43d8qfxqq

quinta-feira, 8 de março de 2012

APEC 2012 DR. FRED LEE PLENARY



VIDEO LINK :https://ieeetv.ieee.org/player/html/viewer#apec-2012-dr-fred-lee-plenary

Dr. Fred Lee, University Distinguished Professor, Virginia Tech gives an in-depth talk about Current Mode Control and Modeling.
Time: 1:30 pm – 2:00 pm

Speaker: Dr. Fred Lee

University Distinguished Professor

Virginia Tech

"Current Mode Control and Modeling- 3 Decades of Progress"
fred_lee_image

The paper starts with a review of the history of development of current mode control and various modeling attempts. The topic of modeling for current mode control, although seemingly settled, still left many unsolved issues. Arthur Brown proposed the discrete time domain sample-data modeling, in the 80’s, which accurately predicted the sub-harmonic oscillation associated with the peak current model control. Subsequently, Brown’s discrete time domain model was reformulated and simplified by Ray Ridley in frequency domain to offer it as a design-oriented modeling and analysis tool. The discrete time sample-data modeling was essentially based on constant frequency operation. It has limited applications to other forms of current-mode control, such as variable frequency control and average current-mode control.

El Presidente Sebastián Piñera lanza nueva Ley de Incentivo Tributario a la INVESTIGACION Y DESARROLLO



[06/03/2012] El Presidente Piñera resaltó que al cumplir casi la mitad de su Gobierno "este compromiso y dedicación a la innovación y el emprendimiento, ya comienzan a rendir frutos. No es casualidad que la economía chilena esté creciendo como está creciendo, de hecho acabamos de conocer las cifras del Imacec, que mostraron un crecimiento del 5,5% en el mes de enero y un crecimiento récord en materia de salarios".

El Presidente de la República, Sebastián Piñera, acompañado de los ministros de Hacienda, Felipe Larraín, y Economía, Pablo Longueira, encabezó la ceremonia de publicación de la ley que establece un incentivo tributario a la inversión privada en investigación y desarrollo (I+D).

En la ceremonia que también contó con la presencia del ministro de Educación, Harald Beyer, el vicepresidente de Corfo, Hernán Cheyre, y los presidentes de CNIC y CONICYT, Fernando Flores y José Miguel Aguilera, respectivamente, el Mandatario explicó que esta nueva ley "es una asociación entre la sociedad y el emprendedor. La sociedad representada por el Estado y el innovador representado por todos aquellos que tienen en el alma esa fuerza y voluntad para cambiar la forma en que hemos hecho las cosas".
Aseguró que "no solamente aumentamos el monto del incentivo, no solamente ampliamos el ámbito de aplicación del incentivo, antes era solamente extramuros, ahora también es intramuros, queremos que esta ley permita un profundo desarrollo en nuestra capacidad de innovar y emprender".

En esa línea, manifestó que "al tener un crédito del 35%, que se descuenta de los impuestos, y el resto se descuenta como gasto, en la práctica, el financiamiento es compartido, la mitad el Estado, la otra mitad el emprendedor".

El Jefe de Estado aprovechó la oportunidad para repasar lo que está haciendo el Gobierno en materia de innovación y emprendimiento. Destacó las "exenciones tributarias del impuesto de primera categoría para las Pymes, para que tengan ese capital de trabajo que les permita reinvertir".

Recordó "la reducción del impuesto de timbres y estampillas a la mitad y la simplificación de los tiempos, trámites y costos para crear una empresa, que bajaron sustancialmente, y que van a seguir bajando".
Asimismo, manifestó la importancia de los programas CORFO "de apoyo a los emprendedores, que ya suman más de 2600 millones de dólares y que han favorecido a más de 167 mil pequeños y medianos empresarios".
El Presidente Piñera resaltó que al cumplir casi la mitad del Gobierno "este compromiso y dedicación a la innovación y el emprendimiento, ya comienzan a rendir frutos. No es casualidad que la economía chilena esté creciendo como está creciendo, de hecho acabamos de conocer las cifras del Imacec, que mostraron un crecimiento del 5,5% en el mes de enero y un crecimiento récord en materia de salarios".

Agregó que "el promedio de crecimiento durante nuestro Gobierno, desde abril de 2010 hasta enero de 2012, es de 6,3%. Hemos duplicado el ritmo de crecimiento que teníamos en el Gobierno anterior".
FUENTE:http://sebastian-pinera-presidente.blogspot.com/