The wind turbine generation system (WTGS) exhibits a nonlinear characteristic and its maximum power point varies with changing atmospheric conditions. In order to operate the WTGS at maximum power output under various wind speeds and to avoid using speed encoder in practical applications, it is necessary to improve the controller system to operate the maximum power points in the WTGS. There are three factors to influence wind generator, the wind speed, power coefficient and the radius of blade. The power coefficient depends on the blade pitch angle and tip speed ratio (TSR). The objective of the dissertation is to develop an intelligent controlled wind energy conversion system (WECS) using AC/DC and DC/AC power converters for grid-connected power application. To achieve a fast and stable response for the real power control, an intelligent controller was proposed, which consists of a fuzzy neural network (FNN), a recurrent fuzzy neural network (RFNN), a wilcoxcon radial basis function network (WRBFN) and a improved Elman neural network (IENN) for MPPT. Furthermore, the parameter of the developed FNN, RFNN, WRBFN and IENN are trained on-line using back-propagation learning algorithm. However, the learning rates in the FNN, RFNN, WRBFN, and IENN are usually selected by trial and error method, which is time-consuming. Therefore, modified particle swarm optimization (MPSO) method is adopted to adjust the learning rates to improve the learning capability of the developed RFNN, WRBFN and IENN. Moreover, presents the estimation of the rotor speed is based on the sliding mode and model reference adaptive system (MRAS) speed observer theory. Furthermore, a sensorless vector-control strategy for an induction generator (IG) operating in a grid-connected variable speed wind energy conversion system can be achieved. On the other hand, a WRBFN based with hill-climb searching (HCS) maximum-power-point-tracking (MPPT) strategy is proposed for permanent magnet synchronous generator (PMSG) with a variable speed wind turbine. Finally, many simulation results are provided to show the effectiveness of the proposed intelligent control wind generation systems.

The declining cost of photovoltaic (PV) modules has enabled the vision of ubiquitous photovoltaic (PV) power to become feasible. Emerging PV technologies are facilitating the creation of intentionally non-flat PV modules, which create new applications for this sustainable energy generation currently not possible with the traditional rigid, flat silicon-glass modules. However, since the photovoltaic cells are no longer coplanar, there are significant new requirements for the power electronics necessary to convert the native form of electricity into a usable form and ensure maximum energy harvest. Non-uniform insolation from cell-to-cell gives rise to non-uniform current density in the PV material, which limits the ability to create series-connected cells without bypass diode or other ways to shunt current, which is well known in the maximum power tracking literature. This thesis presents a modeling approach to determine and quantify the variations in generation of energy due to intentionally non-flat PV geometries. This will enable the power electronics circuitry to be optimized to harvest maximum energy from PV pixel elements – clusters of PV cells with similar operating characteristics. This thesis systematically compares different geometries with identical two-dimensional projection "footprints" for energy harvest throughout the day. The results show that for the same footprint, a semi-cylindrical surface harvests more energy over a typical day than a flat plate. The modeling approach is then extended to demonstrate that by using non flat geometries for PV panel, the availability of a remotely located stand-alone power system can be increased when compared to a flat panel of same footprint. These results have broad application to a variety of energy scavenging scenarios in which either total energy harvested needs to be maximized or unusual geometries for the PV active surfaces are required, including building-integrated PV. This thesis develops the analysis of the potential energy harvest gain for advanced non-planar PV collectors as a necessary first step towards the design of the power electronics circuits and control algorithms to take advantage of the new opportunities of conformal and non-flat PV collectors.

This thesis deals with quantifying the merits of Distributed Maximum Power Point Tracking (DMPPT), as well as providing solutions to achieve DMPPT in PV systems. A general method based on 3D modeling is developed to determine the energy yield of PV installations exploiting different levels of DMPPT granularity. Sub-string-level DMPPT is shown to have up to 30% more annual energy yield than panel-level DMPPT. A Multi-Input-Single-Output (MISO) dc-dc converter is proposed to achieve DMPPT in parallel-connected applications. A digital current-mode controller is used to operate the MISO converter in pseudo-CCM mode. For series-connected applications, the virtualparallel concept is introduced to utilize the robustness of the parallel connection. This concept is demonstrated on a three-phase boost converter. The topology offers reduced output voltage ripple under shading which increases the life-time of the output capacitor. The prototypes yield output power benefits of up to 46% and 20% for the tested shading conditions.

Neste trabalho apresenta-se o modelo de um controlador baseado em Lógica Fuzzy para um sistema de energia baseado em fonte renovável solar fotovoltaica (photovoltaic - PV) multi-string em operação isolada, para o aproveitamento da máxima potência desta fonte. O sistema é composto por painéis solares, conversor CC-CC tipo elevador de tensão (boost), armazenamento por banco de baterias, inversor trifásico e carga trifásica variável. O sistema fotovoltaico foi modelado no MATLAB/Simulink de forma a representar a curva característica V-I do módulo PV, e que é baseado nos dados disponíveis em data-sheets de painéis fotovoltaicos comerciais. Outros estudos de natureza elétrica tais como o cálculo dos valores eficazes das correntes no conversor CC-CC, para avaliação das perdas, indispensáveis para o dimensionamento de componentes eletrônicos, foram realizados. O método tradicional Perturb and Observe de rastreamento do ponto de máxima potência (Maximum Power Point Tracking MPPT) de painéis foi testado e comparado com métodos que usam a Lógica Fuzzy. Devido ao seu desempenho, foi adotado o método Fuzzy que realiza o MPPT por inferência do ciclo de trabalho de um modulador por largura de pulso (Pulse Width Modulation - PWM) através da variação da potência pela variação da corrente do painel solar. O modelo Fuzzy adotado neste trabalho foi testado com sucesso. Os resultados mostraram que ele pode ser robusto e atende à aplicação proposta. Segundo alguns testes realizados, este controlador pode realizar o MPPT de um sistema PV na configuração multi-string onde alguns arranjos fotovoltaicos são usados. Inclusive, este controle pode ser facilmente adaptado para realizar o MPPT de outras fontes de energia baseados no mesmo princípio de controle, como é o caso do aerogerador. / This work presents the model of a Fuzzy Logic controller for a renewable energy system based on multi-string solar photovoltaic (PV) in stand-alone operation, to extract the maximum energy of this power source. The system consists of PV modules, DC-DC converter (Boost), a battery set, three-phase inverter and three-phase variable load. The photovoltaic system was modeled in MATLAB / Simulink in order to represent the V-I characteristic of the PV module, and which is based on the data provided by the manufacturer data-sheet. Other studies, such as the calculation of the RMS currents of the DC-DC converter components for evaluation of the losses, which are essential for the system design were accomplished. The conventional Perturb and Observe method for the Maximum Power Point Tracking (MPPT) of PV modules was tested and compared with methods that use Fuzzy Logic control. Due to its performance, it was adopted the Fuzzy method that performs the MPPT by inference of duty cycle of a Pulse Width Modulation (PWM) through the variation of PV power divided by the variation of the PV current. The Fuzzy model considered in this work was successfully tested. The results showed that it can be robust and suitable to the proposed application. According to some accomplished tests, the controller can perform the MPPT of a multi-string configuration of the solar PV system, in which several PV arrays are used. Moreover, it can also be easily adapted to perform the MPPT of other energy power sources based on the same control principle, as it is in the case of aerogenerators.

Neste trabalho apresenta-se o modelo de um controlador baseado em Lógica Fuzzy para um sistema de energia baseado em fonte renovável solar fotovoltaica (photovoltaic - PV) multi-string em operação isolada, para o aproveitamento da máxima potência desta fonte. O sistema é composto por painéis solares, conversor CC-CC tipo elevador de tensão (boost), armazenamento por banco de baterias, inversor trifásico e carga trifásica variável. O sistema fotovoltaico foi modelado no MATLAB/Simulink de forma a representar a curva característica V-I do módulo PV, e que é baseado nos dados disponíveis em data-sheets de painéis fotovoltaicos comerciais. Outros estudos de natureza elétrica tais como o cálculo dos valores eficazes das correntes no conversor CC-CC, para avaliação das perdas, indispensáveis para o dimensionamento de componentes eletrônicos, foram realizados. O método tradicional Perturb and Observe de rastreamento do ponto de máxima potência (Maximum Power Point Tracking MPPT) de painéis foi testado e comparado com métodos que usam a Lógica Fuzzy. Devido ao seu desempenho, foi adotado o método Fuzzy que realiza o MPPT por inferência do ciclo de trabalho de um modulador por largura de pulso (Pulse Width Modulation - PWM) através da variação da potência pela variação da corrente do painel solar. O modelo Fuzzy adotado neste trabalho foi testado com sucesso. Os resultados mostraram que ele pode ser robusto e atende à aplicação proposta. Segundo alguns testes realizados, este controlador pode realizar o MPPT de um sistema PV na configuração multi-string onde alguns arranjos fotovoltaicos são usados. Inclusive, este controle pode ser facilmente adaptado para realizar o MPPT de outras fontes de energia baseados no mesmo princípio de controle, como é o caso do aerogerador. / This work presents the model of a Fuzzy Logic controller for a renewable energy system based on multi-string solar photovoltaic (PV) in stand-alone operation, to extract the maximum energy of this power source. The system consists of PV modules, DC-DC converter (Boost), a battery set, three-phase inverter and three-phase variable load. The photovoltaic system was modeled in MATLAB / Simulink in order to represent the V-I characteristic of the PV module, and which is based on the data provided by the manufacturer data-sheet. Other studies, such as the calculation of the RMS currents of the DC-DC converter components for evaluation of the losses, which are essential for the system design were accomplished. The conventional Perturb and Observe method for the Maximum Power Point Tracking (MPPT) of PV modules was tested and compared with methods that use Fuzzy Logic control. Due to its performance, it was adopted the Fuzzy method that performs the MPPT by inference of duty cycle of a Pulse Width Modulation (PWM) through the variation of PV power divided by the variation of the PV current. The Fuzzy model considered in this work was successfully tested. The results showed that it can be robust and suitable to the proposed application. According to some accomplished tests, the controller can perform the MPPT of a multi-string configuration of the solar PV system, in which several PV arrays are used. Moreover, it can also be easily adapted to perform the MPPT of other energy power sources based on the same control principle, as it is in the case of aerogenerators.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-09-12T14:19:20Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Artur_Muniz_Dissertacao_Digital_Biblioteca.pdf: 14042205 bytes, checksum: 21290a8d10774b2848f16e9351043b9a (MD5) / Made available in DSpace on 2016-09-12T14:19:20Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Artur_Muniz_Dissertacao_Digital_Biblioteca.pdf: 14042205 bytes, checksum: 21290a8d10774b2848f16e9351043b9a (MD5) Previous issue date: 2016-02-26 / FACEPE / A curva da potência em função da tensão nos terminais de uma conexão em série de módulos fotovoltaicos, com diodos de passagem protetores, exposta a um sombreamento parcial, exibe um comportamento com múltiplos picos. Os múltiplos picos tornam as estratégias clássicas de seguimento do ponto de máxima potência, ou MPPT, ineficazes. Em primeiro momento, este trabalho realiza uma análise estatística que determina uma região trapezoidal no plano tensão potência onde o ponto de máxima potência global está inserido para qualquer situação de irradiâncias múltiplas e temperatura, para configurações com inversor central e módulos conectados em séries puras ou conectadas em paralelo. Em segundo momento, este trabalho pesquisa as técnicas de MPPT Global que rastreiam o ponto de máxima potência global de uma curva tensão potência com múltiplos picos. Duas destas técnicas são estudadas a fim de avaliar a rapidez em encontrar o ponto de máxima potência global e a energia perdida na busca. Por fim, é proposta uma nova técnica de MPPT Global baseada no estudo estatístico preliminar. Esta nova técnica é proposta tirando proveito do trapézio delimitado na análise estatística. / The power-voltage characteristic of series arrays of photovoltaic modules with bypass diodes under partial shading conditions, displays a multiple peaks behavior. The multiple peaks make the classical algorithms of maximum power point tracking, or MPPT, ineffective. At first, this work performs a statistical analysis that determines a trapezoidal region in the power voltage plan where the global maximum power point is situated for any situation from multiple irradiances and any temperature, for central inverter configuration with a series array of modules or parallel connected series arrays. Soon after, this paper researches the Global MPPT techniques that track the global maximum power point of power-voltage curves with multiple peaks. Some of these techniques are studied to assess how fast they can find the global maximum power point and the energy lost at this search. Finally, it is proposed a new Global MPPT technique based on the preliminary statistical study. This new technique is proposed taking advantage of the trapezoidal region defined in the statistical analysis.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The constant human need for electricity, as well as the increasing demand for energy causes the use of finite sources, as oil and coal. The search for alternative energy sources as wind harvesting is the motivation for this master dissertation. Wind energy is a consolidated technology, mostly based on three blades wind turbine. This master thesis constitutes an analysis of a non-conventional wind machine, named Magnus wind turbine. The turbine s operation is based on the Magnus effect and its difference with respect to the traditional type is that it has rotating cylinders instead of fixed blades, which benefits an increase of generated power, since this turbine can produce power from low wind speeds. A method to track the maximum power point based on the control of the cylinders rotation is proposed, whereas in literature only fixed values were found for this variable. This Magnus turbine is used to drive a permanent magnet synchronous generator as a way to prove the theoretical predictions. The electrical generator also uses a specific method to track the maximum power point for the whole set. Simulated and practical results are demonstrating the performance of the Magnus wind turbine driving a permanent magnet synchronous generator. / A constante necessidade de energia elétrica, assim como o aumento de demanda, implica no uso de fontes de energia que são finitas, como o petróleo e o carvão. A busca por fontes alternativas de energia como a eólica é a motivação para este trabalho, também por a energia eólica ser uma tecnologia já consolidada, utilizando principalmente turbinas de três pás para a geração de energia. Esta dissertação trata da análise de uma turbina eólica não convencional, conhecida como turbina eólica Magnus para acionamento de geradores elétricos. A operação desta turbina é baseada no efeito Magnus e seu grande diferencial é que ao invés de pás fixas possui cilindros giratórios que ajudam no incremento de potência, já que a turbina pode produzir potência mesmo com baixas velocidades de vento. Um método de rastreamento de máxima potência é proposto baseando no controle da velocidade de rotação dos cilindros, já que na literatura são considerados apenas valores fixos para esta variável. A turbina Magnus é acoplada a um gerador síncrono a imã permanente, como forma de demonstração da precisão do método proposto na determinação do seu ponto de máxima potência. Paralelo a isto, o gerador também utiliza um método de rastreamento de máxima potência para que o conjunto inteiro trabalhe no ponto de máxima potência. Os resultados de simulação e práticos são apresentados para demonstrar o desempenho da turbina Magnus acoplada a um gerador síncrono a imã permanente.

Abstract This thesis presents measuring techniques as well as measured and simulated results with the aim of helping the design of photovoltaic energy harvesting systems. Therefore, cost-effective measurement setups were developed for collecting the amount of irradiation, for both stationary and moving photovoltaic (PV) installations. The impact of the time resolution of solar radiation data on estimating the available solar energy was investigated. For moving PV installations, the dynamics and the rate of changes in the available irradiation were studied in order to analyse the effects on maximum power point tracking (MPPT) algorithms. In addition, possibilities for harvesting PV energy in indoor environments were also investigated. The main contribution of this thesis is the effective testing of PV cells and complete PV panels: instead of measuring the characteristic I-V (Current-Voltage) response under strictly controlled artificial illumination, photovoltaics are simply biased externally. Then, with the help of synchronized thermography (ST), infrared (IR) images of the PV panel self-heating are recorded. In the obtained IR-images, defected areas are seen as cold spots, since they are not biased by the external power supply. From the calculated temperature variations, the size of the defect area can be calculated and, thus, the loss in output power can be estimated. The method is shown to work both with and without glass encapsulation. / Tiivistelmä Tämä työ esittelee mittaustekniikoita ja mitattuja ja simuloituja tuloksia aurinkoenergian keruujärjestelmien suunnittelun avuksi. Työtä varten kehitettiin kustannustehokas mittausjärjestelmä, jonka avulla arvioitiin aurinkoenergian määrää sekä stationaarisen että liikkuvan valokennon tapauksissa. Näiden lisäksi tutkittiin mittaustaajuuden vaikutusta arvioitaessa saatavilla olevan aurinkoenergian määrää. Liikkuvan PV (photovoltaic)-asennuksen avulla tutkittiin saatavilla olevan aurinkoenergian vaihtelun suuruutta ja nopeutta tarkoituksena analysoida näiden vaikutuksia käytettäviin MPPT-algoritmeihin. Tämä lisäksi tutkittiin myös valoenergian keruumahdollisuuksia sisätiloissa. Työn tärkein kontribuutio on valokennojen ja kokonaisten valopaneelien toiminnallisuuden testaamisen tehostaminen. Tyypillisesti PV:n toiminnallisuus varmistetaan tarkasti määritetyssä ympäristössä suoritetun I-V -ominaiskäyrämittauksen avulla. Tämän työn menetelmä on yksinkertaisesti biasoida PV:t ulkoisesti, minkä jälkeen ST (synchronized thermpgraphy) -kuvauksen avulla määritetään PV-paneelien itselämpenemistä kuvaavat infrapunakuvat. Paneelin vioittuneet alueet erottuvat IR-kuvissa kylminä alueina ulkoisen biasoinnin puuttuessa. IR-kuvista havaituista lämpötilavaihteluista on mahdollista määrittää vioittuneen alueen koko ja siten arvioida myös menetettyä lähtötehoa. Kyseisen metodin toimivuus osoitettiin niin lasikoteloiduilla kuin ilman sitä olevilla PV-paneeleilla.

Ce mémoire traite de la problématique d’hybridation éolienne-hydrolienne. Elle pose d’abord l’hypothèse d’une éolienne basée sur une Machine Synchrone à Aimants Permanents (MSAP) et une hydrolienne utilisant une Machine Asynchrone à Double Alimentation (MADA). Puis, elle présente la modélisation des différents éléments qui composent chacune des chaines de conversion, de la turbine à la connexion au réseau en passant par la machine électrique et les convertisseurs statiques. Des stratégies de commande y sont aussi développées. Celles-ci permettent d’extraire le maximum d’énergie tout en tenant compte des limites des systèmes. La thèse étudie également deux possibilités de couplage d’une éolienne et hydrolienne qui toutes deux utilisent une MSAP. Les résultats de simulation obtenus des modèles que nous avons développés dans l’environnement Matlab/Simulink/ SimpowerSystem permettent de valider les stratégies de commande utilisées et de conclure qu’un bon choix serait d’opter pour le couplage au niveau du bus continu. / AThis thesis addresses the problem of wind-tidal turbines hybridization. It first raises the hypothesis of a wind turbine based on Synchronous Permanent Magnet Machine (PMSM) and a tidal using a Double-Fed Induction Generator (DFIG). So, it presents the modeling of different elements that make up each system studied, from the turbine to the network connection through the electric machine and static converters. Control strategies are also developed. These are used to extract the maximum energy while taking into account the limitations of the systems. The thesis also examines two possible coupling of wind and tidal turbines which both use a PMSM. The simulation results of the models that we have developed in Matlab / Simulink / SimpowerSystem allow to validate the control strategies and conclude that a good choice would be to opt for coupling to the DC bus.

This master’s thesis is an introduction to switching mode power supplies, especially focused on digital control. It summarizes the basic topologies of switching mode power supplies, and discusses the fundamental issues of digital power supply control. It also summarizes basic informations about Piccolo microcontrolers, about experimental kit and about main parts of sample source code. Also is described here own implementation of the control law and the theory and implementation of maximum power point tracking. The conclusion of this thesis deals with implemantation a testing of the designed digitally controled switching power supply.