POWER ELECTRONICS AND STATIC CONVERTERS GROUP - LEP
Members
1
Goldemberg, Clóvis
Kaiser, Walter2
Komatsu, Wilson3
Matakas Jr., Lourenço4
Contact
Walter Kaiser
Escola Politécnica da USP
Depto. Eng. de Energia e Automação Elétricas
Av. Prof. Luciano Gualberto trav.3 no. 158
CEP 05508-900, São Paulo, SP
Fone: +55(11)3091-5483;
email:[email protected]
Foreword
Power Electronics is a multidisciplinary area
which deals with static conversion of electrical
energy in its various forms, aiming the adequate
control of power flux with high efficiency and
quality. By static conversion one understands
conversion with no moving parts, using high
power semiconductors (transistors, thyristors,
diodes and other electronic switches) operating in
switched mode (open/closed) and circuit
topologies which allow high levels of electrical
system utilization and conservation.
Power Electronics Laboratory (LEP) of the
Electrical Energy and Automation Department
(PEA) research subjects include industrial
applications
(illumination
converters,
electrothermic converters, power supplies,
electrical machines drives etc.), electrical energy
distribution and transmission (high voltage direct
current systems, static reactive compensation, new
topologies for high power converters) and static
converters control. Developing research themes
have practical applications and the methodology
involves computer simulation of the circuits
followed by construction of prototypes to validate
the results (small scale prototypes depending on
application
demand).
Because
of
its
multidisciplinary character, LEP interacts with
various research groups within and without the
University, with government institutions and
private companies, in order to comply with theirs
specific necessities. The following presentation
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2
3
4
Elétricas
Assistant Professor - PEA
Associate Professor - PEA
Assistant Professor - PEA
Assistant Professor - PEA
PEA - Depto. Eng. de Energia e Automação
present abstracts of the main active research
projects.
1. Research Projects:
1.1 High pressure sodium (HPS) lamps
stabilized by power pulses
Coordinator: Prof. Dr. Walter Kaiser
Collaborator :Dr. Alexander Fernandéz Corrêa
This work proposes the study of HPS lamps
fed with power pulses, with the goal of changing
the correlated temperature color of the emitted
light. From the spectral distribution, the
phenomena related with emitted radiation from
the lamp fed by sinusoidal current at mains
frequency were characterized. In this study, the
lamp is fed with nominal power, in an operation
cycle, with a train of current pulses of high
intensity and short period, followed by a low
amplitude alternating current in order to maintain
the electrical arc. Spectroscopic measurements
were done with conventional HPS lamps and low
mercury content ones, from many manufacturers,
as well as measurements of the acoustic emissions
from the discharge tubes. Spectral distributions
were obtained, and the behavior of the correlated
color temperature, color reproduction index and
the lamp’s emitted flux with the variation of the
parameters of the pulsed operation were analyzed.
Keywords: High pressure sodium (HPS) lamp,
pulsed operation, color temperature, color
reproduction index.
1.2 Electrical machines drives and power
electronics simulation software
Coordinator: Prof. Dr.Clóvis Goldemberg
Simulation software applied to drives using
asynchronous AC machines, DC machines and
electronically commutated permanent magnet
machines. The software has immediate
application in power electronics, electrical
machines and drive systems education. The
interactivity provided by it allows the student easy
parameters changes and the consequent vision of
its effects. Same kind software, but with increased
complexity, have applications on electrical
machines and drive systems projects.
Keywords: simulation software, electrical
machines, permanent magnets electrical machines.
Eletrônica de Potência - PEA/EPUSP
1.3 Voltage restorer device with reactive
compensation and active harmonics filtering
functions: mini-DVR
Coordinator: Prof. Dr. José Antonio Jardini.
Collaborators: Prof. Dr. Lourenço Matakas JR,
Prof. Dr. Wilson Komatsu, Dr. Luiz Carlos
Magrini, Antonio Ricardo Giaretta, Mauricio
Galassi, Dra. Fabiana A T Silva, Mário Masuda,
Fernando Ortiz Martinz, Marco Antonio de
Oliveira.
This project device has two objectives: a) to
recompose the momentary voltage transitories,
avoiding unwanted production stops in industrial
plants, caused by the occurrence of voltage sags
and swells caused by electrical system
transitories; b) to compensate part of the reactive
power of the electrical system, collaborating with
the maintenance of the voltage stability of the
electrical system.
Keywords: Dynamic voltage restorer (DVR),
sags; power system harmonics, power electronics.
Foments: CPFL – Companhia Paulista de Força e
Luz, R$ R$ 532.800,00.
1.4 Development and implementation of
FACDS in distribution systems - Flexible
Alternating Current Distribution Systems
Coordinator: Prof. Dr. José Antonio Jardini.
Collaborators: Prof. Dr. Lourenço Matakas JR,
Prof. Dr. Wilson Komatsu, Dr. Luiz Carlos
Magrini, Antonio Ricardo Giaretta, Mauricio
Galassi, Dra. Fabiana A T Silva, Mário Masuda,
Fernando Ortiz Martinz, Marco Antonio de
Oliveira.
This project aims the development and
implementation of FACDS systems for effective
use in medium voltage distribution systems.
Keywords:
Flexible
Alternating
Current
Distribution Systems (FACDS), electrical energy
distribution; power system harmonics, power
electronics.
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change. This control simplicity opposes to the
lack of flexibility to impose simultaneous water
flux and temperature control. So, an electronic
power control is offered in more sophisticated
models, have harmonics and flicker effect
generation problems. This work proposes an
controller based on modified integer semi-cycles
aiming the elimination of AC current harmonics
and flicker effect usually present on conventional
controllers.
Keywords: Integer cycles power control, halfcycle power control, flicker effect, quality of
energy, direct water heater, power electronics.
1.6 Project and Construction of a Dynamic
Voltage Restorer (DVR)
Coordinator: Prof. Dr. Wilson Komatsu
Collaborator: Maurício Galassi.
The growing use of sensitive loads in industrial
applications lead to a concern on interruption and
damages caused to complex production lines. This
work presents a power electronics based solution
capable of compensating Voltage Sags, Voltage
Swells and Harmonic Distortions to acceptable
values on load voltage through an injection
transformer series connected between AC mains
and load, fed by a PWM converter. Project
characteristics for a Dynamic Voltage Restorer
(DVR) are detailed, and control strategies are
compared. One alternative is chosen and
implemented with a DSP (Digital Signal
Processor) controller. Experimental results for a
5kVA prototype are presented.
Keywords: Dynamic Voltage Restorer (DVR),
Voltage Sags; Voltage Swells, AC line harmonics,
Power Electronics.
1.7 Analysis of the Three-phase Bridge
Rectifier with Series Capacitors on AC
Branches (CCC Converter)
Coordinator: Prof. Dr. Walter Kaiser
Foments: CPFL – Companhia Paulista de Força e
Luz, R$ 505.584,00
Collaborator: José Alberto Fernandes Ferreira
Júnior
1.5 Electronic power control on direct water
heaters with optimized semi cycles
Capacitive commutation converters are line
commutated converters which have capacitors
connected in series with the inductances on AC
branches. Those capacitances improve DC voltage
regulation and allow operation with negative
firing angles. This work presents the equations of
the capacitive commutation and of the voltage
versus current characteristic on the DC side of the
converter, assuming converter symmetry and
perfect current smoothing, as well as an analysis
of the capacitance values range which allows
converter operation.
Coordinator: Prof. Dr. Wilson Komatsu
Collaborator: Cláudio José de Oliveira Júnior.
Modern direct water heaters, also known as
electric showers and passage water heaters, have
heating elements constituted by nickel-chrome or
iron-aluminum-chrome wound wire electrical
resistances. Water temperature control is usually
done by water flux control and resistance tap
Eletrônica de Potência - PEA/EPUSP
Keywords: Rectifier, electrolysis rectifier, power
electronics.
1.8 Four Wire, Three Phase Voltage Source
Converters: Proposal of Implementation and
Modulation Strategy by Pulse Width
Modulation
3
Keywords:
Converters
control,
PWM
modulation, power electronics, voltage source
converter.
1.10 Method for Real Time Extraction of
Positive and Negative Sequences and
Harmonics
Coordinator: Prof. Dr. Lourenço Matakas Jr.
Coordinator: Prof. Dr. Lourenço Matakas Jr.
Collaborator: Walter Pereira da Silva Júnior
Collaborator: Rodrigo Cutri
This work presents the study of a four wire, three
phase voltage source converter (VSC3P4W)
applicable in active power filters, motor drives
and voltage inverters. A pulse width modulation
(PWM) with triangular carrier and optimal zero
sequence injection strategy (CPWMZ) is
proposed. This strategy, obtained by a graphical
optimization method, minimizes the converter
current ripple and presents the same behavior and
performance of a space vector PWM (SVPWM).
Simulation and experimental results of a
prototype are presented in order to validate the
strategy.
One of the most common problems in Three
Phase Power Systems is the load unbalance and
harmonics, which cause losses and interferences
on the System. In order to detect or eliminate such
problems the analyzer or compensator must
detect, in real time, the amount of positive and
negative sequence and harmonics. This work
proposes a generic method for real time extraction
of positive and negative sequence and harmonics
which does not require base transformation nor
signal filtering. The proposed method is verified
via numerical simulation and experimentally
implemented on a DSP. As a application example,
an Active Power Filter is presented, using a
voltage source converter operating in PWM.
Keywords: PWM modulation, power electronics,
voltage source converter.
1.9 Study on Strategies for Tracking AC
Current and Voltage on a Voltage Source
Converter.
Keywords: Energy quality, converter control,
PWM modulation, power electronics, voltage
source converter.
Coordinator: Prof. Dr. Lourenço Matakas Jr.
2. Relevant Publications (2006-2007)
Collaborator: Fernando Ortiz Martiz
2.1 Publications in Periodicals
This work presents some control strategies to
achieve voltage and current tracking at the AC
side of Voltage Source Converters with L or LC
output filters. The topology of voltage control is
the Multi-loop control with two loops: Voltage
(outer loop) and Current Loop (inner loop). The
proposed methodology consists in modeling the
control system (plant and controllers), tuning of
the controller parameters, simulating the complete
system including inverter and controller,
implementation of the proposed control strategies
on a Digital Signal Processor (DSP) and tests in a
power converter. The thesis is initially focused on
a state variable continuous time controller with
two states and then discrete-time strategies which
consider the actuation delay due to the time
required to evaluate the control algorithm are
studied. In these discrete-time models, predictive
controllers in voltage and current loops are
analyzed, as well as the use of ProportionalIntegral (PI) controllers in the Voltage Loop.
These two last control topologies are tested in a
low-power inverter for several load conditions
with sinusoidal 60Hz inverter reference voltage
and with harmonic distortion in the inverter
reference voltage.
KAISER, W., CORREA, Alexander Fernández,
MARQUES, Ricardo Paulino. Sound emissions
from pulse operated High-Pressure-Sodium
lamps. IEEE Transactions on Industry
Applications. , v.43, p.1199-1206, 2007.
MARTINZ,
Fernando
Ortiz,
GALASSI,
Maurício, GIARETTA, Antonio Ricardo,
OLIVEIRA, Marco Antonio de, SILVA, Fabiana
Aparecida de Toledo, MASUDA, Mario,
COPELIOVITCH, Simão, ZANETTI, Eric
Rubens,
LIMA,
Eduardo
Gonçalves,
CAMARGO, Josué, AHN, Se Un, MATAKAS
JR, Lourenço, KOMATSU, W., ANTONIO,
Jardini José. A Low Power Voltage Sag
Compensator. Revista Brasileira de Eletrônica de
Potência (SOBRAEP). , v.11, p.77-84, 2006.
KOMATSU, W., OLIVEIRA JÚNIOR, Cláudio
José de, CARVALHO, Paulo Sérgio Valle Direct
water heater power control for reduced
harmonics and flicker content with optimized
half-cycle power control. Revista Brasileira de
Eletrônica de Potência (SOBRAEP). , v.11,
p.175-180, 2006.
2.2 Books
Eletrônica de Potência - PEA/EPUSP
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2.2.1 Book Chapters
3. Intellectual Property
2.5 Prizes
2.6 Other Relevant Publications
2.6.1 Ph.D. Thesis
CUTRI, RODRIGO Método de extração em
tempo real de seqüência positiva, negativa e/ou
harmônicos. Escola Politécnica da Universidade
de São Paulo. 2007. Ph.D. Thesis. PEA.
2.6.2 Master Dissertations
FERREIRA
JÚNIOR,
JOSÉ
ALBERTO
FERNANDES. Análise do retificador trifásico em
ponte com capacitores em série nos ramos CA.
Escola Politécnica da Universidade de São Paulo.
2007. Master Dissertation. PEA.
SILVA JÚNIOR, WALTER PEREIRA DA.
Conversores do Tipo Fonte de Tensão Trifásico
com Quatro Fios: Proposta de Implementação e
Estratégia de Modulação por Largura de Pulso.
Escola Politécnica da Universidade de São Paulo.
2007. Master Dissertation. PEA.
ORTIZ MARTINZ, FERNANDO. Estudo
Estratégias de Rastreamento da Corrente e
tensão CA de um Conversor do Tipo Fonte
Tensão. Escola Politécnica da Universidade
São Paulo. 2007. Master Dissertation. PEA.
de
da
de
de
OLIVEIRA JÚNIOR, CLÁUDIO JOSÉ DE.
Controle eletrônico de potência em aquecedores
elétricos de passagem por semi ciclos
otimizados, Escola Politécnica da Universidade de
São Paulo. 2006. Master Dissertation. PEA.
GALASSI, MAURÍCIO. Projeto e Construção de
um Restaurador Dinâmico de Tensão. Escola
Politécnica da Universidade de São Paulo. 2006.
Master Dissertation. PEA.
3. Performance Indicators