Made available in DSpace on 2014-06-12T17:39:29Z (GMT). No. of bitstreams: 2 arquivo6912_1.pdf: 2837512 bytes, checksum: b5cc7e4c872a99fdbcdd55d799817492 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007 / Esta dissertação apresenta a importância do uso da energia solar fotovoltaica em relação ao impacto ambiental causado pelas fontes de energia convencionais. O fato da energia solar fotovoltaica ser uma energia livre de poluentes e crescente devido à diminuição dos preços dos painéis fotovoltaicos a deixa em condições de competir com as outras fontes de energia. São apresentados aspectos gerais sobre geração fotovoltaica e são discutidos o princípio de funcionamento, o processo de fabricação, os tipos de células solares e as características elétricas dos módulos fotovoltaicos. Também é dada ênfase a um estudo sobre como obter o ponto de máxima potência nos painéis fotovoltaicos. Os métodos de rastreamento do ponto de máxima potência dos módulos fotovoltaicos são discutidos detalhadamente. Resultados de simulações são apresentados com a finalidade de avaliar os métodos apresentados. Algumas variações dos métodos são apresentadas e um resumo dos resultados de simulações é apresentado em tabelas. Os métodos de rastreamento são comparados com o objetivo de implementar a melhor técnica a ser aplicada ao sistema fotovoltaico. Além disso, são apresentadas algumas topologias de conversores que podem ser usadas em um sistema fotovoltaico. Estas topologias são comparadas em termos de eficiência do sistema, já levando em conta o método de rastreamento escolhido anteriormente. Para isso, um breve estudo de perdas nos dispositivos semicondutores também é desenvolvido. Finalmente, é apresentado o sistema fotovoltaico escolhido para um sistema de irrigação

Idénergie develops the first domestic hydrokinetic turbine for rivers. Itaims at producing about 100W in a 1.4m/s river to power up remote locations.Idénergie’s turbine has two main advantages: a completely watertight shaftlessgenerator and an integrated smart converter. The first turbines are planned tobe sold in June 2014.To be able to test the embedded intelligence in the lab, Idénergie’s testbench must be able to reproduce river conditions. Measurements have beenperformed in a river and provide the torque developed by the river at differentspeeds. On the test bench controlled by a LabView program, the rotationalspeed is measured and the corresponding torque computed. This torque is setas the new command and makes the test bench behave as if it was driven by aturbine in a river.Idénergie’s generator contains a rotor made of permanent magnets.These magnets are provided by a supplier and their quality needs to bechecked. For this purpose, a magnetometer is designed and built. It contains 5Hall effect sensors which move at a constant speed above a magnet andmeasure its magnetic field. The magnetometer is able to compare magnets to areference and to detect the faulty ones. The sensors are also used to measurethe magnetic field of the rotor and show that the custom-made shape of themagnets has no influence on the sinusoidal field.The converter transforms the three-phase current to direct current andcontrols the rotational speed. This is done thanks to an embedded electroniccard, which is about to be working properly. The Maximum Power PointTracking algorithm ensures that the rotational speed is optimum in order toproduce the maximum power output. The code loaded on this card is written inits main part but needs to be tested on the test bench once the card will beoperational.

Les travaux présentés dans cette thèse introduisent des systèmes PV/Stockage couplés au réseau de distribution. La question principale qui se pose dans cette thèse : "Comment intégrer et exploiter un tel système de production d’électricité décentralisés pour renforcer un réseau de distribution fragile ?". Afin de répondre à cette question, dans un premier temps, la modélisation du réseau de distribution (modèle du réseau et modèle de consommation domestique) et du système hybride (modèle du panneau PV, modèle de la batterie au plomb et modèle des convertisseurs) est étudiée en prenant en compte les pertes. Pour le système PV/Stockage, une nouvelle approche de MPPT (Maximum Power Point Tracking en anglais) est développée en considérant le courant moyen passant dans la diode du hacheur. Par ailleurs, une étude du problème de déséquilibre triphasé est menée en utilisant un onduleur triphasé. Egalement, une approche du dimensionnement de l’onduleur a été proposée en se basant sur le courant indirect des trois courants des charges. Pour l’échange de l’énergie entre ces ressources renouvelables et le réseau, tout d’abord, nous avons proposé une nouvelle stratégie pour récupérer l’énergie optimale du système PV + hacheur + batterie idéale. Nous avons ensuite étudié l’échange énergétique (en termes de puissance active et réactive) entre d’un générateur actif et le réseau en utilisant un onduleur. Dan un second temps, nous avons tenté de répondre à la question de l’optimisation de l’injection des sources renouvelables (en termes de capacité et de localisation) dans un réseau de distribution. Pour un dimensionnement fixe du système PV/Stockage (surface de PV, capacité de la batterie et courants de calibre des convertisseurs) ainsi que celui de Stockage/Onduleur sans PV, la gestion optimale de l’énergie de ce système est présentée en respectant les contraintes du réseau ainsi que l’état de charge de la batterie. Nous avons également considéré l’injection de la production du système PV/Stockage dans un seul nœud et deux nœuds à la fois. Finalement, le dimensionnement optimal du système PV/Stockage ainsi que celui de Stockage/Onduleur a été étudié en se basant sur le coût des composants de ces systèmes. Cette étude est aussi intégrée la stratégie optimale de l’énergie précédente. / This thesis presents the integration of the distributed energy sources (PV/Storage) connected to the electric power distribution network. The main question here is: "how to integrate and exploit these sources in order to strengthen a fragile distribution network?". To respond to this question, we started by modeling of the distribution network (domestic consumption model and low-voltage distribution network model) and a hybrid system (solar cell model, lead-acid battery model and converters models) while taking into account the losses. Concerning the PV/Storage system, a new approach of MPPT (Maximum Power Point Tracking) is developed based on the average current passing through the diode. We also studied the three-phase imbalance by using a three-phase inverter (also called three-phase corrector). An approach of the corrector sizing is proposed based on the indirect current of three current-loads. To study the power transfer between the distributed energy sources and the network, first of all, we proposed a new strategy to optimize the energy generated from the PV + chopper + ideal battery system into the electric network. An inverter is studied in order to transfer power (in terms of active and reactive power) between an active generator and the electric network. Secondly, optimization approaches for sizing and placing distributed generators in the electric network are presented. For a fixed sizing of the PV/Storage system (the area of photovoltaic, the capacity of battery and the nominal currents of converters) as well as Storage/Inverter system, the energy flow management strategies are carried out by respecting the constraints of the network as well as the state of charge of battery. We also considered the injection from the PV/Storage system into only one node as well as into two nodes simultaneously. Finally, the optimal sizing of the PV/Storage system as well as the Storage/Inverter system are studied based on the investment cost of each component of these systems. This approach takes into account the energy flow management strategies.

This thesis begins with providing a basic introduction of electricity requirements for small developing country communities serviced by small scale generating units (focussing mainly on small wind turbine, small Photo Voltaic system and Micro-Hydro Power Plants). Scenarios of these small scale units around the world are presented. Companies manufacturing different size wind turbines are surveyed in order to propose a design that suits the most abundantly available and affordable turbines. Different Maximum Power Point Tracking (MPPT) algorithms normally employed for these small scale generating units are listed along with their working principles. Most of these algorithms for MPPT do not require any mechanical sensors in order to sense the control parameters like wind speed and rotor speed (for small wind turbines), temperature and irradiation (for PV systems), and water flow and water head (for Micro-Hydro). Models for all three of these systems were developed in order to generate Maximum Power Point (MPP) curves. Similarly, a model for Permanent Magnet Synchronous Generators (PMSGs) has been developed in the d-q reference frame. A boost rectifier which enables active Power Factor Correction (PFC) and has a DC regulated output voltage is proposed before implementing a MPPT algorithm. The proposed boost rectifier works on the principle of Direct Power Control Space Vector Modulation (DPC-SVM) which is based on instantaneous active and reactive power control loops. In this technique, the switching states are determined according to the errors between commanded and estimated values of active and reactive powers. The PMSG and Wind Turbine behaviour are simulated at various wind speeds. Similarly, simulation of the proposed PFC boost rectifier is performed in matlab/simulink. The output of these models are observed for the variable wind speeds which identifies PFC and boosted constant DC output voltage is obtained. A buck converter that employs the MPPT algorithm is proposed and modeled. The model of a complete system that consists of a variable speed small wind turbine, PMSG, DPC-SVM boost rectifier, and buck converter implementing MPPT algorithm is developed. The proposed MPPT algorithm is based upon the principle of adjusting the duty ratio of the buck converter in order reach the MPP for different wind speeds (for small wind turbines) and different water flow rates (Micro-Hydro). Finally, a prototype DPC-SVM boost rectifier and buck converter was designed and built for a turbine with an output power ranging from 50 W-1 kW. Inductors for the boost rectifier and buck DC-DC converter were designed and built for these output power ranges. A microcontroller was programmed in order to generate three switching signals for the PFC boost rectifier and one switching signal for the MPPT buck converter. Three phase voltages and currents were sensed to determine active and reactive power. The voltage vectors were divided into 12 sectors and a switching algorithm based on the DPC-SVM boost rectifier model was implemented in order to minimize the errors between commanded and estimated values of active and reactive power. The system was designed for charging 48 V battery bank. The generator three phase voltage is boosted to a constant 80 V DC. Simulation results of the DPC-SVM based rectifier shows that the output power could be varied by varying the DC load maintaining UPF and constant boosted DC voltage. A buck DC-DC converter is proposed after the boost rectifier stage in order to charge the 48 V battery bank. Duty ratio of the buck converter is varied for varying the output power in order to reach the MPP. The controller prototype was designed and developed. A laboratory setup connecting 4 kW induction motor (behaving as a wind turbine) with 1kW PMSG was built. Speed-torque characteristic of the induction motor is initially determined. The torque out of the motor varies with the motor speed at various motor supply voltages. At a particular supply voltage, the motor torque reaches peak power at a certain turbine speed. Hence, the control algorithm is tested to reach this power point. Although the prototype of the entire system was built, complete results were not obtained due to various time constraints. Results from the boost rectifier showed that the appropriate switching were performed according to the digitized signals of the active and reactive power errors for different voltage sectors. Simulation results showed that for various wind speed, a constant DC voltage of 80 V DC is achieved along with UPF. MPPT control algorithm was tested for induction motor and PMSG combination. Results showed that the MPPT could be achieved by varying the buck converter duty ratio with UPF achieved at various wind speeds.

This thesis proposes an implementation of a DSP-Based single-phase small-scale photovoltaic energy conversion system. The conversion system converts dc power generated by photovoltaic cells into ac power. A digital signal processor and a combined circuit with push-pull and full-bridge architectures are used in this study to reduce the complexity of the circuit design. Several operation and protection functions, such as maximum power point tracking, over/under voltage protection, over current protection, over/under frequency protection and detection of islanding operation are considered in the design. The operation performance of the conversion system at different stages is analyzed. The proposed conversion system can supply the local loads and feed excess power to the utility network with unit power factor (grid-connection mode), or it can supply loads exclusively (stand-alone mode). The simulation and experimentation results are presented and discussed to show the performance of the photovoltaic system and verify the feasibility of the proposed energy conversion system.

The aim of this master's thesis is suggest and construct regulator for charge NiMH storage battery from photovoltaic (PV) panel. Function regulator is tracking maximum power point from PV panel (MPPT), control charge and evaluation full charge of battery.

Made available in DSpace on 2018-08-02T00:00:38Z (GMT). No. of bitstreams: 1 tese_10498_dissertacao_Netalianne.pdf: 5417301 bytes, checksum: 5f643d84188fcaeb6044feefa4b71257 (MD5) Previous issue date: 2016-12-08 / Devido à necessidade do emprego de técnicas de rastreamento do ponto de máxima potência no estudo de energia solar fotovoltaica, e considerando a dificuldade de viabilizar ensaios e testes em laboratório, este trabalho consiste em modelar um arranjo fotovoltaico representando o efeito do sombreamento parcial em arranjos como referência para emuladores de módulos PVs. As características nominais de um módulo fotovoltaico são descritas por meio de um modelo matemático que, por simulação computacional, estabelece uma corrente de referência para emulação de um conjunto de módulos conectados em série. O modelo matemático utilizado é adaptado para representar os efeitos de sombreamento parcial a que são expostos os arranjos fotovoltaicos, e a corrente de referência disponibilizada é utilizada como referência de corrente do laço de controle de um conversor CC que deve conseguir imitar o comportamento de um arranjo fotovoltaico com sombreamento parcial. O algoritmo para adequação aos efeitos de sombreamento parcial, o projeto do emulador e os resultados obtidos são apresentados considerando diferentes níveis de radiação do Sol e para diferentes condições de sombreamento parcial. A partir dos resultados apresentados e comparados com um sistema de referência foi possível obter uma resposta satisfatória para a representação de arranjos série de módulos em situação de sombreamento parcial. Os resultados de cálculo de desvios se mantiveram abaixo da faixa de tolerância prevista pelo fabricante do módulo comercial utilizado. O conversor projetado e a sintonia do controlador obtiveram bom funcionamento para todas as condições de irradiância mostradas com um bom comportamento dinâmico, sendo capaz de representar as características elétricas do arranjo de maneira adequada.

No description available.

DC nano-grid system shows promising prospect and enjoys some advantages over AC micro-grid system. It enables easier integration of multiple renewable energy sources with multiple loads. Photovoltaic (PV) is essentially a typical renewable source that serves as main power source in DC nano-grid system. Traditional PV system includes centralized PV system, string PV system and micro-converter PV system. More recently, smart converter PV system has been introduced and shown great improvement in aspects of power generation achieved by distributed Maximum Power Point Tracking (MPPT). It is also advantageous over micro-converter PV system due to lower cost and flexibility. Detailed case study demonstrates that power generation efficiency can be easily compromised because of mismatch between different panels in centralized and string PV systems. In smart converter PV system, this problem can be solved due to distributed MPPT for each individual panel. The smart converter system has a very wide voltage range within which all panels can generate maximum power. The location and the width of this range are subject to change under different mismatch conditions. A second stage converter is needed to locate the array MPPT range. However, there is instability problem when doing second stage MPPT with traditional methods. Modified methods based on conductance control and resistance control are analyzed and compared. Both methods can solve the MPPT instability problem. However, in terms of steady state performance, resistance control MPPT is more promising in terms of higher utilization ratio and faster tracking speed. It is because both methods are of inherited variable operating point step size with constant conductance or resistance perturbation step size. However, the operating point change decreases with resistance perturbation but increases with conductance perturbation otherwise. Therefore, resistance control MPPT is chosen as a good candidate. Both simulation and experimental results verifies the concept. / Master of Science

Nos sociétés sont de plus en plus préoccupées par l’impact très nocif des ressources énergétiques polluantes, essentiellement, le pétrole, le charbon et le gaz. Ainsi, l’intérêt dans l’utilisation des énergies renouvelables et propres est en constant augmentation et la conception de nouveaux systèmes énergétiques est devenue un challenge scientifique et technologique. Pour concevoir de nouvelles solutions énergétiques compétitives et efficaces, les fabricants de composants (panneaux solaires, pile à combustible, convertisseurs, etc.) et les secteurs industriels concernés sont confrontés à des problématiques d’optimisation, de contrôle et de durabilité. Par ailleurs, les sources d’énergie renouvelable sont dépendantes de plusieurs facteurs incontrôlables (lieu géographique, météorologie, etc.). Pour parer à ces facteurs, et donc au caractère aléatoire de disponibilité énergétique, l’hybridation des sources et la gestion énergétique peut s’avérer être une approche pertinente pour la conception de solutions énergétiques efficaces. Cette thèse est une contribution au problème de l’hybridation et de la gestion d’énergie. Plus précisément, nous considérons un système hybride composé de panneaux solaires photovoltaïques et d’une pile à combustible. Ce système est supposé être doté de convertisseurs et d’un système de stockage (batterie et super-condensateurs). / Our societies are increasingly concerned about the very harmful impact of clean energy resources, mainly oil, coal and gas. Thus, interest in the use of renewable and clean energy is constantly increasing and the development of new energy systems has become a scientific and technological challenge. To develop new competitive and efficient energy solutions, manufacturers of components (solar panels, fuel cells, inverters, etc.) and industrial sectors are facing problems of optimization, control and durability. In addition, renewable energy sources depend on several uncontrollable factors (geographical location, weather, etc.). To address these factors, and thus the randomness of energy availability, sources hybridization and energy management can prove to be an appropriate approach for the design of efficient energy solutions. This thesis is a contribution to the problem of hybridization and energy management. More precisely, we consider a hybrid system composed of photovoltaic solar panels and a fuel cell. This system is supposed to be equipped with converters and storage system (battery and supercapacitors). The goal is to develop control strategies to extract the maximum power available from the considered sources and to optimize the overall energy system to meet the load requirements. To do this, our approach is based on the tracking of the maximum power point and the use of compensators.