A Modified Harmonics Reduction Technique for a Three-Phase Controlled Converter

A Modified Harmonics Reduction Technique
for a Three-Phase Controlled Converter
Ali M. Eltamaly
Abstract—Three-phase controlled converters have many applications
especially in adjustable speed drives and renewable energy.
A three-phase controlled converter is a good option in these applications
due to its low cost, simplicity, and maintainability with
respect to other solutions like a full-bridge insulated gate bipolar
transistor converter or a Vienna rectifier. Line current harmonics
in this converter is very high; therefore, a harmonics reduction
technique is needed to remedy the problem. In this paper, an
improved injection current technique is introduced to reduce line
current harmonics. The optimal amplitude and phase angle of
the injection current for different loads and firing angles have
been mathematically determined. Simulation for this technique
has been performed by using the PSIM simulation program. An
experimental prototype has been built to verify the mathematical
and simulation results. The simulation and experimental results
show a sensitive variation in the total harmonic distortion of
the line current for the amplitude and angle of injection current
variations. The simulation and experimental results prove the
superiority of this technique in mitigating the requirements for
harmonics standards.
FULLPAPER HERE:http://repository.ksu.edu.sa/jspui/bitstream/123456789/6648/1/Modified%20Harmonics%20Reduction%20Technique%20for%20a%20Three-Phase%20Controlled%20Converter.pdf

LINK2:http://www.mediafire.com/?96w252ckdl10953

Aplicacion de LaPlace (Cir.Elect.)(UTP) parte 1

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

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/

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

Thevenin's Theorem - by Prof. Dr. C. B. Bangal

Lecture - 11 The Graph Theory Approach for Electrical Circuits(Part-I)