DC-AC CONVERTER FOR STANDALONE POWER SYSTEM

ABSTRACT
Abstract of dissertation presented at Universidade Federal do Ceará as partial of
fulfillment of the requirements for the Master degree in Electrical Engineering.
DC-AC CONVERTER FOR STANDALONE POWER SYSTEM
The study and development of new topologies or combinations of these in order to
apply for autonomous systems of electric power supply are the main drivers of this work. The
project consists of the combination of two converters, one high-gain step-up converter based
on the three states switching cell whose role is to raise the battery voltage to a value of
400Vcc, thus forming a DC bus, and a single-phase inverter bridge-type with a LC filter,
using the bipolar modulation type to obtain sinusoidal voltage similar to the power grid. The
control of the high-gain converter is performed through a loop of current and voltage, both
analog, but some part of the voltage loop is performed internally in a dsPIC, and inverter
control is largely accomplished through this dsPIC (Digital modulator and controller), using
the principles of discrete control. This system is capable of converting from 48V DC batteries
in 220Vac and 60 Hz, with performance equal to or greater than 85% with a wide range of
loading. Each stage has its theoretical study developed, and the introduction of a methodology
for obtaining a reduced model of the high gain converter, and at the end, after the
specifications and sizes are shown the experimental results of the prototype developed. The
system was tested in various situations that can be found in everyday life, like starting a nonlinear load, for example.
Engo .LUIZ DANIEL S. BEZERRA
CONVERSOR DE ALTO GANHO ASSOCIADO A UM INVERSOR
PARA APLICAÇÃO EM SISTEMA AUTÔNOMO DE ENERGIA
ELÉTRICA
Dissertação submetida à Universidade Federal
do Ceará como parte dos requisitos para
obtenção do grau de Mestre em Engenharia
Elétrica.
Orientador: Prof. Dr. René Pastor Torrico Bascopé.
Fortaleza Julho 2009

UNIDADE DE OSMOSE REVERSA ACIONADA POR ENERGIA SOLAR

UNIDADE DE OSMOSE REVERSA ACIONADA POR ENERGIA SOLAR
FOTOVOLTAICA SEM BATERIAS:
Simulação, Projeto e Validação Experimental
FORTALEZA 2005-CEARA-BRASIL
Dissertação submetida à
Universidade Federal do Ceará
como parte dos requisitos para a
obtenção do grau de Mestre em Engenharia Elétrica.
DOUGLAS BRESSAN RIFFEL

ABSTRACT
RIFFEL, D.B.; 2005. Photovoltaic-powered Reverse Osmosis Plant without
Batteries: Simulation, Design and Experimental Validation. Fortaleza. Thesis
(Master degree) – Centro de Tecnologia, Universidade Federal do Ceará.125p.
This research analyzes the combination of photovoltaic generation with
reverse osmosis desalination of brackish water for the supply of dinking water.
Access to potable water and electric power is still an unresolved problem for many
people around the world. The State of Ceará, where this research was carried out,
represents well this reality. A photovoltaic-powered reverse osmosis plant was
installed in laboratory. Through the elimination of the battery, investment costs and
maintenance need could be reduced. At the same time, this changes completely
the operation of the unit, being totally subordinate to the instantaneous conditions
of solar radiation and temperature. A plant design procedure was elaborated that
uses solar radiation statistical data and the seasonal availability of water from
cisterns as design parameters. Two systems were mathematically modeled and
validated by experiment. System 1 uses a motor-pump directly coupled to two 55
Wp photovoltaic modules. System 2 disposes of one additional module and a DCDC
buck converter with maximum power point tracking between the photovoltaic
array and the load. The necessity to regulate the power transferred to the load in
System 2, led to the development of the converter and the tracking algorithm
specially for this application. The simulations allowed the comparison between the
two systems in two conditions: with and without a pressure relief valve coupled to
system 1. Results shown that the System 2 has always a better performance, as a
daily permeate water production, time operation, specific consumption and in the
relationship photovoltaic installed capacity per produced water liter. It was
observed that volumetric pumps, of the diaphragm type in the case, are suitable
for reverse osmosis applications. But, when combined with a photovoltaic array,
maximum power point tracking is necessary. It is important to state that with a
50 % increment in generation capacity a 90% increase in permeate production is
achieved.
Key-words: photovoltaic generation, reverse osmosis, brackish water desalination,
solar energy.

Convertisseurs génériques Applications pour le domaine aéronautique

THESE
présentée pour obtenir le titre de
DOCTEUR DE L’INSTITUT NATIONAL POLYTECHNIQUE DE TOULOUSE
Ecole doctorale : Génie Electrique, Electronique, Télécommunications
Spécialité : Génie Electrique
Par
Jérôme MAVIER

Convertisseurs génériques à tolérance de panne
Applications pour le domaine aéronautique
Abstract
Electric power is of increasing importance in aeronautical systems. As a consequence,
static converters have become widespread, and power electronics is crucial for improving
performance, reliability and competitiveness.
The aim of this thesis is to contribute to the design of electrical networks by using
modular generic converters. To determine their structure, an inventory of power electronics
applications is carried out in the framework of a "more electric" aircraft.
The modularity of these power conversion blocks opens the way for power
segmentation and redundancy, that enables systems availability to increase. Following this
approach, several fault-tolerant inverter topologies are compared, both analytically and by
simulation based on the physical model of a flight surface electrohydrostatic actuator.
For the experimental studies, power electronics modules are designed to operate a
reconfigurable inverter that is dedicated to a permanent magnet synchronous motor drive.
Connected to the neutral point of the wye-connected motor, this inverter has a fourth leg that
acts as a mutualised redundancy.
Lastly, to extend the power electronics generic module’s field of application, three
AC/DC converter topologies are proposed in order to improve power management, in
comparison with conventional topologies, with respect to electrical and thermal design
criteria.

Soutenue le 22 mars 2007 devant le jury composé de :
MM. P. LE MOIGNE Rapporteur
F. MEIBODY-TABAR Rapporteur
F. FOREST Examinateur
L. PRISSE Examinateur
F. RICHARDEAU Encadrant
H. PIQUET Encadrant
P. ROLLIN Invité
Thèse préparée au Laboratoire Plasma et Conversion d’Energie (LAPLACE) – site ENSEEIHT
Unité Mixte de Recherche INPT – UPS – CNRS N°5213

DESIGN METHODOLOGY OF A HIGH POWER DENSITY

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