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Junqueira, Alisson Dias. "Retificador trifásico com elevado fator de potência." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-19112004-151457/.
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Este trabalho trata da retificação trifásica com elevado fator de potência. São mostradas algumas soluções encontradas na literatura. Dentre elas, optou-se pela utilização de um conversor trifásico autocomutado do tipo fonte de tensão (VSC), operando em modulação em largura de pulso (PWM). Apresenta-se a modelagem do conversor, que é utilizado para o projeto dos controladores responsáveis pelo rastreamento das correntes da rede CA e pela regulação da tensão CC. O projeto do controlador das correntes CA, baseado na estratégia de dead-beat, é mostrado de forma simples e intuitiva e é discutida a estabilidade deste controlador. O projeto do controlador PI utilizado para a regulação da tensão CC é baseado no modelo linearizado do conversor. É utilizado um algoritmo simples e eficiente para o bloco PLL, baseado na estratégia dead-beat. O comportamento do sistema completo é verificado teoricamente, por simulações numéricas e resultados experimentais, confirmando o excelente desempenho das estratégias de controle e do método de projeto propostos. São discutidos ainda os efeitos da variação nos parâmetros no desempenho e na estabilidade do sistema.This study investigates three-phase rectifiers with high power factor. Some existing solutions in the literature are presented. One of them, the three-phase voltage source converter (VSC) rectifier with pulse width modulation (PWM) is chosen to be used. Converter modeling is presented and used to design a mains current tracking controller and a DC voltage regulator. AC current controlling based on the deadbeat strategy is presented in a simple and intuitive way, and the stability of this controller is discussed. The DC side PI controller is designed based on the linearized model of the converter. A simple and efficient PLL block algorithm, based on the deadbeat strategy is presented. The behavior of the complete system is verified theoretically, by numerical simulation and experimental results, confirming the excellent performance of the proposed control strategy and method of design. The effects of parameter mismatch on system performance and stability are also discussed.
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Imhoff, Johninson. "Desenvolvimento de conversores estáticos para sistemas fotovoltaicos autônomos." Universidade Federal de Santa Maria, 2007. http://repositorio.ufsm.br/handle/1/8608.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThis work presents a new energy conditioning system for application in stand-alone photovoltaic systems with battery bank. Firstly, the characteristics of solar photovoltaic energy, the modeling of a photovoltaic cell and the equivalent electrical circuit are presented. In a second moment, the photovoltaic generation systems and a review of the static converters applied to stand-alone photovoltaic systems with battery bank are presented. From this study it is proposed a new photovoltaic generation system, with distributed energy processing based on series-connected DC-DC converters. The proposed system presents better utilization of the energy generated by the panels through the employment of more than one array of photovoltaic panels and a static power converter for each subsystem. Thereby, the losses through shading are reduced, and also the reliability of the system is increased, once even if one of the subsystems fails, the system will keep on generating electricity to the loads of higher priority. Posteriorly, the analyses of the operation of the system and simulation results are presented. Finally, it is presented experimental results, comparing the efficiency of the utilization of the energy generated by the input stage of the proposed system and by a system traditionally employed in stand-alone photovoltaic systems, showing an energy gain of 16% with the utilization of the proposed system for situations in which at least one panel is shaded.
Esta dissertação de mestrado apresenta um novo sistema de condicionamento de energia para aplicação em sistemas fotovoltaicos autônomos com banco de baterias. Inicialmente são apresentadas as características da energia solar fotovoltaica, a modelagem de uma célula fotovoltaica e um circuito elétrico equivalente. Em um segundo momento são apresentados os sistemas de geração fotovoltaica e uma revisão dos conversores estáticos aplicados a sistemas fotovoltaicos autônomos com banco de baterias. A partir deste estudo é proposto um novo sistema de geração fotovoltaica, com processamento distribuído de energia baseada em conversores CC-CC conectados em série. O sistema proposto apresenta um melhor aproveitamento da energia gerada pelos painéis através da utilização de mais de um arranjo de painéis fotovoltaicos e o emprego de um conversor estático de potência para cada subsistema. Assim, as perdas por sombreamento são reduzidas bem como é aumentada a confiabilidade do sistema, pois mesmo com a falha de um dos subsistemas o sistema continuará garantindo energia elétrica para as cargas de maior interesse. Posteriormente, são apresentadas as análises do funcionamento do sistema e resultados de simulação. Por fim, resultados experimentais são apresentados, comparando a eficiência no aproveitamento da energia gerada pelo estágio de entrada do sistema proposto e de um sistema tradicionalmente empregado em sistemas fotovoltaicos autônomos, demonstrando um ganho de energia de 16% com a utilização do sistema proposto para situações em que pelo menos um painel está sombreado.
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Kirsten, André Luís. "Reator eletrônico para lâmpadas de descarga em alta pressão baseado no conversor biflyback inversor." Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/8494.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe study of the best utilization of high intensity discharge lamps deals with the great global concern with energy efficiency. Electronic ballasts are the current devices that can make the good use of high luminous efficacy and the long useful life of these lamps. This work aims to develop an electronic ballast to supply high intensity discharge lamps. In order to avoid the acoustic resonance phenomenon occurrence, the lamp is supplied with low frequency square waveform. Power control and voltage inversion stage in the lamp are developed by the biflyback inverter topology. The analysis and design of this topology were performed, as well as the development of resonant inversion methodology of the lamp voltage. It is proposed one study, qualitative and quantitative, of active converters to provide the power factor correction, and their integration with the biflyback inverter topology. Buck biflyback inverter topology is chosen to the implementation of practical experiments, in order to validate the present work. The converter modeling, considering the lamp dynamic, such as the stability analysis and theoretical control strategy of current and lamp power are presented. Experimental results show that the proposed electronic ballast has the follow characteristics: high power factor (0.97), low input current harmonic distortion, high efficiency (88%) and not visible occurrence of acoustic resonance phenomenon.
O estudo do melhor aproveitamento das características das lâmpadas de descarga em alta pressão vem ao encontro da grande preocupação mundial com a eficientização energética. Reatores eletrônicos são os dispositivos atuais que melhor aproveitam a alta eficácia luminosa e longa vida útil dessas lâmpadas. Este trabalho visa o desenvolvimento de um reator eletrônico para a alimentação de lâmpadas de descarga em alta pressão. De modo a não excitar a ocorrência do fenômeno de ressonância acústica, a alimentação da lâmpada é realizada através de forma de onda de corrente quadrada em baixa frequência. Os estágios de controle de potência e inversão da tensão na lâmpada são realizados pela topologia biflyback inversora. A análise e projeto desta topologia foram realizados, assim como o desenvolvimento de uma metodologia de inversão ressonante da tensão da lâmpada. É proposto um estudo, qualitativo e quantitativo, dos conversores ativos para correção do fator de potência, e a integração destes, com a topologia biflyback inversora. A topologia buck biflyback inversora foi escolhida para a realização de experimentos práticos para a validação do trabalho. A modelagem do conversor, considerando a dinâmica de uma lâmpada de descarga em alta pressão de sódio foi realizada. Assim como a análise da estabilidade e estratégias de controle da corrente e da potência na lâmpada. Os resultados experimentais comprovam que o reator eletrônico proposto apresenta as características desejadas de: alto fator de potência (0,97), atendimento da norma IEC61000-3-2 para o nível das harmônicas da corrente de entrada, elevado rendimento (88%) e não excitação visível do fenômeno de ressonância acústica.
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MAIA, Ayslan Caisson Norões. "Sistemas de conversão de energia multiníveis obtidos através da interconexão de módulos de conversores estáticos de potência de dois níveis." Universidade Federal de Campina Grande, 2016. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1561.
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Nesse trabalho são apresentadas contribuições na área de identificação de sistemas representados em espaço de estados. É proposta uma metodologia completa para estimação de modelos que representem as principais dinâmicas de proessos industriais. O fluxo natural dos procedimentos de identificação consiste da coleta experimental dos dados, seguido pela esolha dos modelos candidatos e da utilização de um critério de ajuste que selecione o melhor modelo possível. Nesse sentido é proposta uma metodologia para estimativa de modelos em espaço de estados, utilizando excitações pulsadas. A abordagem desenvolvida combina algoritmos precisos e eficientes com experimentos rápidos, adequados a ambientes industriais. O projeto das excitações é realizado em tempo real, por meio de informações coletadas em um curto experimento inicial, baseado em uma única oscilação de uma estrutura realimentada por um relé. Esse mecanismo possibilita uma estimativa preliminar do atraso e da constante de tempo dominante do sistema. O método de identificação proposto é baseado na teoria de realizações de Kalman. É apresentada uma reformulação do problema de realizações clássico, para comportar sinais de entrada pulsados. Essa abordagem se mostra computacionalmente e cliente, assim como apresentar resultados semelhantes aos métodos de benchmark. A técnica possibilita também a estimativa de atrasos de transporte e a inserção de conhecimentos prévios por meio de um problema de otimização com restrições via LMI Linear Matrix Inequalities. Em muitos casos, somente as caraterísticas principais dos sistema são relevantes em um projeto de sistema de controle. Portanto é proposta uma técnica para obtenção de modelos de primeira ordem com atraso, a partir da redução de modelos balanceados em espaço de estados. Por fim, todas as contribuições discutidas nesse trabalho de teses não validadas em uma série de plantas experimentais em salas de laboratório. Plantas essas, projetadas e construídas com o intuito de emular o cotidiano operacional de instalações industriais reais.
Static converters are a widely used equipment in power systems to control the electrical energy low between sources and loads. In this context, it is observed a demand for converters topologies that generate high quality waveforms and are capable of supplying loads with ever larger powers. In high power applications such as industrial and power systems, the development of a special class of converters topologies, denominated multilevel converters, has been widely recognized as a viable solution to overcome the operational limits of semiconductor devices. In this work are developed and analyzed multilevel structures of type DC-AC applied to the six-phase machines drives and of type AC-DC-AC feeding singlephase and three-phase loads. These topologies are obtained by interconnecting two-level converters modules in order to optimize the system: reduction of losses in the semiconductor devices, harmonic distortion of the signals and ratings of voltage and/or current in the power switches. For this investigation were performed steady state analyzes, where the operatinglimits of the structures to the imposed control conditions and the behavior of the fundamental component of voltage and current are evaluated. In addition, for each investigated topology, were developed: dynamic models, PWM techniques, control strategies, simulation results and experimental results. The impact of this optimization is quanti ed by calculating the THD and WTHD of the current and voltage signals generated by the converter and by estimating losses in the semiconductor devices. Finally, a comparative study is done using conventional converters as reference in order to evaluate the performance of the proposed topologies
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Marquezini, Diego Dias. "Interação entre conversores chaveados com baixa ondulação e células de combustível." Universidade Federal de Santa Maria, 2007. http://repositorio.ufsm.br/handle/1/8530.
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This dissertation discusses the interaction between fuel cells and the DC-DC converter just connected across its terminals. For that, it presents a modified algorithm to represent the dynamic behavior of fuel cell stacks as much the current ripple effects from power converters on such cells. PEM type fuel cells (Proton Exchange Membrane) are studied to get a reasonable model of the electrochemical and electric characteristics of the involved phenomena in the generation of electric energy from fuel cells. A T filter is used as interface between the fuel cell and the DC-DC converter. This converter must prevent large current ripples going through the cell terminals as well as keeping constant the power flow between the FC and the link DC to prevent itself of possible current transient. To connect it to the grid it was used a three-phase DC-AC converter to inject or to absorb current from the grid at reduced ripple distortion and to stabilize the DC link voltage. DC current controllers were designed to curb the link DC and AC currents within reasonable limits. Validation of the model was carried out through computer simulation in order to have an evaluation of the control system behavior both for the stack and for the injection and/or absorption of energy. Also, theoretical results with practical data from a fuel stack were compared with respect to the load variation across its terminals.Esta dissertação discute a interação entre as células de combustível e o conversor de potência conectado aos seus terminais. Para isto é apresentado um algoritmo modificado para a modelagem dinâmica de conversores chaveados tanto quanto um estudo sobre os efeitos das ondulações de corrente sobre as células. Células do tipo PEM (Proton Exchange Membrane) são estudadas, obtendo-se um modelo razoável para análise das características eletroquímicas e elétricas dos fenômenos envolvidos na geração de energia elétrica com células de combustível. Como interface utiliza-se um conversor CC-CC associado a um filtro do tipo T . Este conversor tem a função de evitar a grande ondulação de corrente absorvida pela célula bem como, manter constante o fluxo de potência entre a FC e o barramento CC evitando-se assim, possíveis transitórios nos terminais da célula. O projeto do conversor de potência prevê a conexão à rede da concessionária através de um conversor CC-CA trifásico para injetar ou absorver corrente da rede com reduzida distorção harmônica e estabilização da tensão do barramento CC. Foram projetados controladores para a corrente CC, a tensão CC e a corrente CA. Como formas de validação foram realizadas simulações para avaliar o comportamento dos sistemas de controle para a pilha e para a injeção e/ou absorção de energia. Também foram comparados os resultados teóricos com os dados práticos de uma pilha submetida à variação de carga em seus terminais.
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Havez, Léon. "Contribution au prototypage virtuel 3D par éléments finis de composants magnétiques utilisés en électronique de puissance." Phd thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/16480/7/havez_leon.pdf.
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Le travail présenté dans ce mémoire concerne le prototypage virtuel 3D des composants électromagnétiques d’électronique de puissance, par la technique des éléments finis. La démarche correspond à la volonté de disposer d’outils de simulation multiphysiques 3D toujours plusperformants, notamment dans le contexte de l’intégration en électronique de puissance. Il s’agit de mettre au point des méthodes et desprocédures adaptées à la caractérisation d’inductances, de transformateurs ou de coupleurs multiphasés haute fréquence, dans unenvironnement de conversion statique, avec des formes d’onde de tension et de courant non sinusoïdales. Cela nécessite de connaître le comportement harmonique des composants électromagnétiques sur une large gamme de fréquence, et de tenir compte des spécificités de réalisation comme l’utilisation de bobinages en technologie feuillard ou planar et de noyaux magnétiques en matériaux ferrite. Dans le premier chapitre de ce mémoire, une analyse des limitations actuelles des modèles analytiques et numériques des composants magnétiques HF en électronique de puissance est faite afin de définir les besoins les plus importants qui seront par la suite abordés. Dans cette optique, le choix de la plateforme ouverte de simulation multiphysique en 3D, par éléments finis, COMSOL Multiphysics, a été fait. En effet, l’objectif ici n’est pas de développer un nouveau code de calcul mais de mettre au point un outil de simulation adapté aux problématiques rencontrées en électronique de puissance. Le deuxième chapitre aborde le point très important de la détermination des pertes cuivre HF en tenant compte des effets fréquentiels tels que les effets de peau et de proximité. La problématique des bobinages feuillards ou planars est résolue par l’utilisation d’éléments coques spécifiques. Le troisième chapitre traite de la détermination despertes fer, à haut niveau d’excitation et pour des formes d’onde de champ non sinusoïdales. Sur la base d’abaques de densités de pertesfournies par les constructeurs de matériaux, deux méthodes de calcul sont proposées, l’une en cours de traitement et l’autre en posttraitement. La prise en compte de la non-linéarité est analysée ainsi que la problématique de l’existence localisée de champs tournants. Le quatrième chapitre aborde l’extraction virtuelle des paramètres électriques des composants électromagnétiques multiphasés et la définition de matrices d’impédances (inductances et résistances propres et mutuelles), en fonction de la fréquence. A l’exception des pertes fer non prise en compte ici, cette formalisation permet de traduire finement le comportement harmonique large bande des composants multiphasés. Finalement, le cinquième chapitre propose trois exemples d’utilisation de ce nouvel outil. Le premier exemple aborde ledimensionnement optimal et la caractérisation virtuelle d’un coupleur triphasé de forte puissance. Le deuxième exemple montre l’intérêt dela modélisation harmonique sous la forme de matrices impédances pour simuler le comportement d’un coupleur hexaphasé in-situ dans unconvertisseur de puissance. Enfin le troisième exemple montre la possibilité de lancer des campagnes d’études paramétriques automatisées pour étudier l’évolution d’un ou plusieurs paramètres dimensionnant afin de calculer des tables de réponses d’aide au dimensionnement.
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Gruson, François. "Modulation naturelle généralisée des convertisseurs matriciels pour la variation de vitesse." Thesis, Ecole centrale de Lille, 2010. http://www.theses.fr/2010ECLI0027/document.
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La variation de vitesse des machines électriques est une application très porteuse de l’électronique de puissance. La solution de conversion la plus répandue consiste à connecter en cascade deux convertisseurs statiques et d’effectuer une double conversion (AC/DC/AC). Une autre solution, faiblement répandue dans l’industrie, effectue une conversion directe AC/AC. Ce mémoire effectue une synthèse sur les solutions de conversion directe ainsi que sur les stratégies de modulation des convertisseurs matriciels et matriciels « double étage » dans le but de piloter des machines électriques triphasées à partir d’un réseau alternatif triphasé. Cette synthèse a permis de développer une modulation scalaire généralisée, associée à un modulateur par porteuse, équivalente à la modulation vectorielle et applicable aux différents convertisseurs matriciels. Les modulations, à nombre de commutation réduit par période de découpage, ont été approfondies. Cette généralisation a permis de mettre en évidence une solution réduisant les pertes et améliorant le comportement électromagnétique du dispositif comparativement aux modulations traditionnellement utilisées. La présentation des contraintes réelles (commande rapprochée des interrupteurs, Les protections ainsi que le filtrage) est abordée et a été utilisée pour développer une maquette laboratoire. Les stratégies de modulation ont été implantées expérimentalement et valident l’étude théorique. Enfin, un fonctionnement direct à la fréquence réseau, sans modulation donc à faibles pertes, est proposé. Un fonctionnement particulier est introduit, permettant d’effectuer le transitoire du mode modulé classique au fonctionnement direct non moduléIn the power electronics field, the adjustable speed drives is a growing application for electric motors control. The most common conversion solution is to connect in series two static converters and perform a double conversion (AC/DC/AC). Another solution, hardly proposed by industry, uses a direct AC/AC conversion. This thesis aims to make a direct conversion solutions and matrix converters and ‘‘two stage’’ matrix converters modulation strategies synthesis for the purpose to control three-phase electric motor with a three phase input network. This synthesis has developed a generalized scalar modulation, combined with a carrier wave modulator, equivalent to the space vector modulation and applied to matrix converters and the ‘‘two stage’’ matrix converters. Some attention has been done to reduced the switching number during the modulation period. The generalization allows to propose a modified modulation which reduces the losses and improves the electromagnetic performance compared to the traditional modulations used for these kind of converters. The practical constraint (switches control, protection system and filtering) are discussed and has been used to develop a laboratory prototype. The modulations strategies have been implemented experimentally and validate the theoretical study. Finally, a direct function mode with an equal frequency between the input and output network is proposed, without modulation and therefore low losses. In the last part, a particular operation mode is then introduced, permitting the transient operation between the modulated conventional mode to the direct mode without modulation
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Jalboub, Mohamed K. "Investigation of the application of UPFC controllers for weak bus systems subjected to fault conditions. An investigation of the behaviour of a UPFC controller: the voltage stability and power transfer capability of the network and the effect of the position of unsymmetrical fault conditions." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5699.
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In order to identify the weakest bus in a power system so that the Unified Power Flow Controller could be connected, an investigation of static and dynamic voltage stability is presented. Two stability indices, static and dynamic, have been proposed in the thesis. Multi-Input Multi-Output (MIMO) analysis has been used for the dynamic stability analysis. Results based on the Western System Coordinate Council (WSCC) 3-machine, 9-bus test system and IEEE 14 bus Reliability Test System (RTS) shows that these indices detect with the degree of accuracy the weakest bus, the weakest line and the voltage stability margin in the test system before suffering from voltage collapse.
Recently, Flexible Alternating Current Transmission systems (FACTs) have become significant due to the need to strengthen existing power systems. The UPFC has been identified in literature as the most comprehensive and complex FACTs equipment that has emerged for the control and optimization of power flow in AC transmission systems. Significant research has been done on the UPFC. However, the extent of UPFC capability, connected to the weakest bus in maintaining the power flows under fault conditions, not only in the line where it is installed, but also in adjacent parallel lines, remains to be studied. In the literature, it has normally been assumed the UPFC is disconnected during a fault period. In this investigation it has been shown that fault conditions can affect the UPFC significantly, even if it occurred on far buses of the power system. This forms the main contribution presented in this thesis. The impact of UPFC in minimizing the disturbances in voltages, currents and power flows under fault conditions are investigated. The WSCC 3-machine, 9-bus test system is used to investigate the effect of an unsymmetrical fault type and position on the operation of UPFC controller in accordance to the G59 protection, stability and regulation. Results show that it is necessary to disconnect the UPFC controller from the power system during unsymmetrical fault conditions.Libyan Government
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Jalboub, Mohamed. "Investigation of the application of UPFC controllers for weak bus systems subjected to fault conditions : an investigation of the behaviour of a UPFC controller : the voltage stability and power transfer capability of the network and the effect of the position of unsymmetrical fault conditions." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5699.
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In order to identify the weakest bus in a power system so that the Unified Power Flow Controller could be connected, an investigation of static and dynamic voltage stability is presented. Two stability indices, static and dynamic, have been proposed in the thesis. Multi-Input Multi-Output (MIMO) analysis has been used for the dynamic stability analysis. Results based on the Western System Coordinate Council (WSCC) 3-machine, 9-bus test system and IEEE 14 bus Reliability Test System (RTS) shows that these indices detect with the degree of accuracy the weakest bus, the weakest line and the voltage stability margin in the test system before suffering from voltage collapse. Recently, Flexible Alternating Current Transmission systems (FACTs) have become significant due to the need to strengthen existing power systems. The UPFC has been identified in literature as the most comprehensive and complex FACTs equipment that has emerged for the control and optimization of power flow in AC transmission systems. Significant research has been done on the UPFC. However, the extent of UPFC capability, connected to the weakest bus in maintaining the power flows under fault conditions, not only in the line where it is installed, but also in adjacent parallel lines, remains to be studied. In the literature, it has normally been assumed the UPFC is disconnected during a fault period. In this investigation it has been shown that fault conditions can affect the UPFC significantly, even if it occurred on far buses of the power system. This forms the main contribution presented in this thesis. The impact of UPFC in minimizing the disturbances in voltages, currents and power flows under fault conditions are investigated. The WSCC 3-machine, 9-bus test system is used to investigate the effect of an unsymmetrical fault type and position on the operation of UPFC controller in accordance to the G59 protection, stability and regulation. Results show that it is necessary to disconnect the UPFC controller from the power system during unsymmetrical fault conditions.
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Rosado, Sebastian Pedro. "Analysis of Electric Disturbances from the Static Frequency Converter of a Pumped Storage Station." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34448.
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The present work studies the disturbances created in the electric system of a pumped storage power plant, which is an hydraulic generation facility where the machines can work as turbines or pumps, by the operation of a static frequency converter (SFC). The SFC is used for starting the synchronous machines at the station when in the pump mode. During the starting process several equipment is connected to the SFC being possible to get affected by the disturbances generated. These disturbances mainly include the creation of transient overvoltages during the commutation of the semiconductor devices of the SFC and the introduction of harmonics in the network currents and voltages. This work analyzes the possible effects of the SFC operation over the station equipment based on computer simulations. For this purpose, the complete system was modeled and the starting process simulated in a computer transient simulator program. The work begins with a general review of the effects of electric disturbances over high voltage equipment and in particular of the disturbances generated by power electronics conversion equipment. Then the models for the different kind of equipment present in the system are discussed and formulated. The control system that governs the operation of the SFC during the starting process is analyzed later as well as the operation conditions. Once the model of the system is set up, the harmonic analysis of the electric network is done by frequency domain and time domain methods. Time domain methods are also employed for the analysis of the commutation transient produced by the SFC operation. Finally, the simulation results are used to evaluate the impact of the SFC operation on the station equipment, especially on the generator step up transformer.Master of Science
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Trainer, D. R. "The application of self commutated converter circuits for static reactive power compensation." Thesis, Staffordshire University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244432.
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Oliveira, Adriano Toniolo de. "Análise e implementação de um circuito de auxílio à comutação integrado aplicado a uma fonte ininterrupta de energia." Universidade Federal de Santa Maria, 2008. http://repositorio.ufsm.br/handle/1/8452.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThis study proposes an auxiliary commutation circuit, applied to a double-conversion uninterruptible power supply, operating with a three-level PWM full-bridge inverter. In order to construct this circuit, we use the concept of integration of auxiliary commutation circuit: the case study of ZVT. The concept of iCAC is not directly applied to three-level PWM inverters. Then, it is necessary the use of classic auxiliary commutation techniques combined with the concept of integration. In this study, it is presented a hybrid auxiliary commutation circuit. Due to the restrictions imposed by the iCAC, just one of the inverter legs can be integrated. To the other inverter leg it is used a conventional auxiliary commutation circuit. The proposed system aims at achieving a better performance if compared to the same uninterruptible power supply operating with a classic ZVT auxiliary commutation circuit. There is also the advantage that all the auxiliary switches operate with ZVS and/or ZCZ soft switching. Through the use of iCAC it is obtained a minimization of circulating reactive energy in the auxiliary commutation circuits and it contributes to increase the global performance of the uninterruptible power supply. The number of additional components is reduced in relation to the classic CAC and, consequently, the system becomes more attractive to the industry. During this study, the analysis of the system and the simulation results are presented. Finally, experimental results are presented, comparing the efficiency of the CAC iZVT proposed system versus the classic CAC ZVT, in order to validate the proposed system.
Este trabalho propõe um circuito de auxílio à comutação, aplicado a uma fonte ininterrupta de energia de dupla conversão, operando com inversor PWM ponte completa modulado em três níveis de tensão. Para obtenção desse circuito, este trabalho utiliza o conceito de integração de circuitos de auxílio à comutação: O estudo do caso ZVT. O conceito de iCAC não é aplicável diretamente a inversores PWM modulados em três níveis de tensão. Dessa forma faz-se necessário a utilização de técnicas clássicas de auxílio à comutação em conjunto com o conceito de integração. A partir deste estudo é proposto um circuito de auxílio à comutação híbrido. Devido às restrições impostas pelo iCAC apenas uma das pernas do inversor pode ser integrada. Para a outra perna do inversor é então utilizado um circuito de auxílio à comutação convencional. O sistema proposto visa obter melhor rendimento em relação à mesma fonte ininterrupta de energia operando com circuito de auxílio à comutação clássicos do tipo ZVT. Há também a vantagem de que todas as chaves auxiliares operam com comutação suave ZVS e/ou ZCS. Com uso do conceito de iCAC é obtida a minimização da energia reativa circulante nos circuitos de auxílio à comutação, o que contribui para elevar o rendimento global da fonte ininterrupta de energia. O número de componentes adicionais é reduzido em relação ao CAC clássico, tornando assim o sistema atrativo à indústria. Ao longo desse estudo, são apresentadas as análises do funcionamento do sistema e resultados de simulação são apresentados. Por fim, resultados experimentais são apresentados, comparando a eficiência do sistema proposto CAC iZVT versus CAC ZVT clássico, para dessa forma validar o sistema proposto.
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Leredde, Alexandre. "Etude, commande et mise en œuvre de nouvelles structures multiniveaux." Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0094/document.
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Les structures de conversion multiniveaux permettent de convertir en moyenne tension et forte puissance. Celles-ci sont construites à partir de cellules de commutations et permettent d’augmenter le courant et la tension en entrée ou en sortie. Ces structures sont appelées multiniveaux car les formes d’ondes des tensions en sortie permettent d’avoir plus de deux niveaux de tension différents. Les différentes structures peuvent être classées dans différentes catégories tel que la mise en série de pont en H, les convertisseurs multicellulaires série ou parallèle ou encore les structures utilisant le fractionnement du bus continu. Toutes ces structures ont des propriétés et applications différentes, même si certaines structures ont des propriétés communes. Il est aussi possible de créer de nouvelles structures en mixant les différentes structures de bases des différentes familles de convertisseurs multiniveaux ou en assemblant les structures de base de la conversion statique. Même si l’utilisation de structure de conversion multiniveaux permet de convertir à forte puissance, celle-ci n’est pas toujours aisée. En effet l’augmentation du nombre de niveaux ou de la tension d’entrée implique également une augmentation du nombre de composants semiconducteurs. Ceci peut être un frein à l’utilisation de convertisseur multiniveaux. Pour cela une nouvelle structure utilisant des composants partagés entre les différentes phases est proposée afin de limiter leur nombre. Un autre problème important lié aux convertisseurs multiniveaux est l’équilibrage des tensions des condensateurs du bus continu si celui-ci est composé de plus de deux condensateurs mis en série. Pour cela plusieurs solutions sont possibles : soit en utilisant une commande spécifique utilisant la modulation vectorielle, soit en utilisant des structures auxiliaires qui ont pour but d’équilibrer les différentes tensions des condensateurs. Dans une dernière partie ont été proposées de nouvelles structures qui permettent à la fois d’augmenter le courant de sortie et la tension en entrée en utilisant les principes des structures de base des convertisseurs multicellulaires série et parallèle. De plus, ces structures ont des propriétés intéressantes sur les formes d’ondes de sortie. De ces structures a été conçu un prototype permettant de valider les résultats de simulation. Une commande numérique implantée sur FPGA a été réalisée et a permis d’avoir des résultats expérimentaux intéressantsThis PhD Thesis deals with the study of new multilevel structures. At the beginning of this work, a new methodology to create new multilevel structures has been conceived. To evaluate the performances of these structures, there are many possibilities: number of output voltage levels, number of components, and the quality of the converters’ output waveforms. The list of criteria is not exhaustive. One technique to obtain an output multilevel waveform is to split the DC link in several capacitors. There is a limitation since putting more than two capacitors in serial connection leads to an unbalancing of these voltage capacitors. Several solutions are possible to balance these voltages. The first one uses the control of the structure in a three phase application, using a space vector modulation and minimizing the energy stored in the DC link. The second solution consists in using auxiliary circuits, which realize an energy transfer between one capacitor to another through an inductor. The drawback of this method is the high number of components. This problem can be reduced sharing some components between the three phases of the converter. The third part of this study is related to multicell converters, structures with very interesting good properties. New converter structures mix serial and parallel multicell converters, to obtain a hybrid converter with similar performances to the two basic converters. An experimental prototype was built to validate the results of the PhD. The digital control of this hybrid structure was made with a FPGA where two DSP processors were implemented
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Cetin, Alper. "Design And Implementation Of A Voltage Source Converter Based Statcom For Reactive Power Compensation And Harmonic Filtering." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608307/index.pdf.
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In this thesis, design and implementation of a distribution-type, voltage source converter (VSC) based static synchronous compensator (D-STATCOM) having the
simplest converter and coupling transformer topologies have been carried out. The VSC STATCOM is composed of a +/- 750 kVAr full-bridge VSC employing selective harmonic elimination technique, a low-pass input filter, and a ∆
/Y connected coupling transformer for connection to medium voltage bus. The power stage of VSC based STATCOM is composed of water-cooled high voltage IGBT modules switched at 850 Hz for the elimination of 5th, 7th, 11th, 13th, 17th, 19th, 23rd,and 25th voltage harmonics. Special care has been taken in the laminated busbar design to minimize stray inductances between power semiconductors and dc link capacitor. Reactive power control is achieved by applying the phase angle control technique. The effect of input filter on total demand distortion has been investigated theoretically by mathematical derivations. The proposed VSC STATCOM has been implemented for reactive power compensation of Coal Preparation System in Kemerkö
y Thermal Power Plant. The field test results have shown the success of the implemented system in view of fast response in reactive power compensation, and minimum input current harmonic content, and compliance with the IEEE Std. 519-1992 even for the weakest power systems. The application of selective harmonic elimination technique and phase angle control to VSC STATCOM has led to optimum switching frequency and device utilization for high voltage IGBTs at the expense of slower response as compared to other PWM techniques.
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Botterón, Fernando. "Controladores discretos de tensão baseados no princípio do modelo interno aplicados a inversores trifásicos PWM." Universidade Federal de Santa Maria, 2005. http://repositorio.ufsm.br/handle/1/3647.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThis thesis contributes to the analysis, project and implementation of discrete-time controllers based on the Internal Model Principle, aiming to improve the performance of three-leg three-phase PWM inverters with insulating output transformer usually found in the output stage of medium power double-conversion UPS. Initially, an investigation about issues concerning to the discrete-time models of three-phase inverters with space vector modulation and the LC filter have been carried out. This investigation shows the impact of different switching sequences, sampling instants and filter cut-off frequency on the harmonic spectrum of sampled variables used for feedback. This is a concern when the switching frequency is low to limit the switching losses as in medium and high power UPS. In this way, this thesis proposes sampling methods that make possible to reduce the low order harmonics on the interest variables, which is relevant when state feedback is used. These methods allow to obtain discrete-time average linear models useful for the controller design. In addition, the saturation of the insulating transformer is addressed in details. The dc component arising from the digital implementation and from the circuit measures non idealities, and then amplified by an inadequate choice of the controller, may lead the transformer to saturate. In order to solve this problem, and in accordance with the Internal Model Principle, internal models adequate to the plant under consideration as well as discrete-time voltage controllers in stationary and synchronous frames which are not prone to amplify the dc component, are proposed. Another goal of this thesis is the improvement of the UPS output voltage transient response due to linear and non linear load steps. This is obtained considering the sampling methods before mentioned, combined with internal models with reduced number of poles and low sampling rate. It is demonstrated that it is possible to improve significantly the output voltage transient responses, as well as to satisfy the rigorous classification of the standard IEC62040-3 for UPS without degrading the steady state performance. In addition, these control structures have enough stability margins, as proved in each case, and they results in simple and attractive solutions to be implemented in 8 or 16 bits fixed-point arithmetic microcontrollers and DSP with reduced memory space. The feasibility of the proposed solutions is verified with experimental results demonstrating both transient and steady-state performances. Finally, a comparative analysis of the proposed control structures, over the light of the standard IEC62040-3, is presented.
A presente tese de doutorado contribui para a análise, projeto e implementação de controladores discretos baseados no Princípio do Modelo Interno, com o intuito de aprimorar o desempenho de inversores trifásicos PWM a três braços com transformador isolador usualmente utilizados no estágio de saída de UPS de dupla conversão de média potência. Inicialmente se realiza uma investigação sobre os aspectos relacionados à obtenção do modelo discreto de inversores trifásicos com modulação space vector e do filtro de saída. Essa investigação mostra o impacto de diferentes seqüências de comutação, instantes de amostragem e freqüência de corte do filtro no conteúdo harmônico das variáveis amostradas usadas para realimentação. Isso é uma preocupação quando a freqüência de comutação é baixa para limitar as perdas em UPS de média e alta potência. Nesse sentido essa tese propõe métodos de amostragem que possibilitam reduzir as harmônicas de baixa ordem nas variáveis de interesse o que adquire importância quando se realiza a realimentação dos estados da planta. Esses métodos permitem a obtenção de modelos médios lineares úteis para o projeto do controlador. Além disso, a saturação do transformador de isolação é analisada em detalhe. A componente contínua oriunda da implementação digital e das não idealidades dos circuitos de medição, e amplificada por uma escolha inadequada do controlador, pode levar o transformador à saturação. Com o intuito de solucionar esse problema, e de acordo com a teoria do Princípio do Modelo Interno, são propostos modelos internos adequados à planta em questão bem como controladores discretos de tensão em eixos estacionários e síncronos, que não tem tendência a amplificar a componente contínua. Outro dos objetivos dessa tese é o aprimoramento da resposta transitória das tensões de saída da UPS na presença de degraus de carga linear e não linear. Isso é obtido considerando-se os métodos de amostragem mencionados acima, combinado com modelos internos com número de pólos e taxa de amostragem reduzidos. Demonstra-se que é possível aprimorar significativamente a resposta transitória das tensões de saída bem como satisfazer a exigente classificação da norma IEC62040-3 para UPS, sem degradar o desempenho de regime permanente. Além disso, essas estruturas de controle possuem suficiente margem de estabilidade, como provado em cada caso, e estas resultam em soluções simples e atrativas para serem implementadas em microcontroladores e DSP de aritmética de ponto fixo, com palavras de 8 e 16 bits e capacidade reduzida de memória. A viabilidade prática das propostas realizadas é verificada com resultados experimentais em regime permanente e transitório. Finalmente, apresenta-se uma análise comparativa das estruturas de controle propostas, sob o enfoque da norma IEC62040-3.
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Scheich, Roland. "Caractérisation et prédétermination des perturbations électromagnétiques conduites dans les convertisseurs de l'électronique de puissance." Grenoble INPG, 1993. https://hal.archives-ouvertes.fr/tel-02020576.
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Les travaux présentés dans ce mémoire ont pour objectif la modélisation des perturbations conduites dans les convertisseurs d'Electronique de Puissance. La caractérisation de ces perturbations émises sur le réseau d'alimentation se fait dans la bande des radiofréquences de 10 kHZ à 30 MHZ. Un chapitre important a été consacré aux notions de base, en traitement du signal, en matière de normes d'émission et de métrologie afin de définir clairement les méthodes et les procédures de mesure. Caractériser les spectres d'émission des convertisseurs d'électronique nécessite d'identifier les sources perturbatrices (origine de phénomènes) ainsi que les chemins de propagation empruntés par les perturbations. Au cours de cette étude, tant pour les chemins, les éléments prépondérants ont été identifiés ainsi qu'une analyse de leur sensibilité a été proposée. Cette méthodologie a été mise au point sur l'exemple simple d'un hacheur série, puis validée sur d'actes types de structure notamment grâce à de nombreux résultats expérimentaux. L'approche et suffisamment générale pour que l'on puisse s'intéresser également aux perturbations générées par une chaîne de conversion d'énergie regroupant plusieurs convertisseurs en cascade. Enfin, une approche unifiée permettant d'intégrer à la fois les perturbations de mode différentiel et de mode commun a été initiée et ouvre des perspectives intéressantes
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Toussaint, Pierre. "De la quasi-resonance introduite dans les convertisseurs, DC-DC de moyenne puissance : application à l'absorption sinusoïdale." Cachan, Ecole normale supérieure, 1994. http://www.theses.fr/1994DENS0013.
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Électronique de commutation pour l'essentiel, l'électronique de puissance met en œuvre des structures de convertisseurs ou la gestion des pertes par commutation pose problème. La commutation commandée lorsqu'elle est associée à des techniques d'aide a la commutation des interrupteurs, donne de bons résultats. Dans la gamme de puissance allant jusqu'a la dizaine de kilowatts, il existe une alternative à cette solution, que l'on désigne par le terme de quasi-résonance. L'étude présentée montre comment l'introduction de la commutation douce au sein de convertisseurs classiques permet d'obtenir d'aussi bonnes performances voire même meilleures, tout en simplifiant quelque peu la topologie des structures. Sa facilite de mise en œuvre est mise en évidence. La problématique du choix des interrupteurs est abordée. Un second problème pose par l'emploi de l'électronique de puissance et par la multiplication de convertisseurs, est la pollution du réseau auquel ils sont connectes. Afin de résorber cette pollution, des convertisseurs dits à absorption sinusoïdale (c. A. S. ) font l'objet d'études en tout points du globe. Une étude bibliographique leur est consacrée et une réalisation propre au laboratoire est détaillée. Ces convertisseurs fonctionnent en commutation commandée, aussi nous sommes nous attaches à développer des structures réalisant cette fonction de c. A. S. Tout en introduisant les techniques de commutation douce. Deux structures de flyback quasi-résonants, de 500 et 1300 w sont étudiées. Chacune consomme un courant sinusoïdal présentant un taux de distorsion inferieur à 10%. Une ébauche de modélisation de l'un de ces convertisseurs est également décrite
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Hadjikypris, Melios. "Supervisory control scheme for FACTS and HVDC based damping of inter-area power oscillations in hybrid AC-DC power systems." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/supervisory-control-scheme-for-facts-and-hvdc-based-damping-of-interarea-power-oscillations-in-hybrid-acdc-power-systems(cc03b44a-97f9-44ec-839f-5dcbcf2801f1).html.
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Modern interconnected power systems are becoming highly complex and sophisticated, while increasing energy penetrations through congested inter-tie lines causing the operating point approaching stability margins. This as a result, exposes the overall system to potential low frequency power oscillation phenomena following disturbances. This in turn can lead to cascading events and blackouts. Recent approaches to counteract this phenomenon are based on utilization of wide area monitoring systems (WAMS) and power electronics based devices, such as flexible AC transmission systems (FACTS) and HVDC links for advanced power oscillation damping provision. The rise of hybrid AC-DC power systems is therefore sought as a viable solution in overcoming this challenge and securing wide-area stability. If multiple FACTS devices and HVDC links are integrated in a scheme with no supervising control actions considered amongst them, the overall system response might not be optimal. Each device might attempt to individually damp power oscillations ignoring the control status of the rest. This introduces an increasing chance of destabilizing interactions taking place between them, leading to under-utilized performance, increased costs and system wide-area stability deterioration. This research investigates the development of a novel supervisory control scheme that optimally coordinates a parallel operation of multiple FACTS devices and an HVDC link distributed across a power system. The control system is based on Linear Quadratic Gaussian (LQG) modern optimal control theory. The proposed new control scheme provides coordinating control signals to WAMS based FACTS devices and HVDC link, to optimally and coherently counteract inter-area modes of low frequency power oscillations inherent in the system. The thesis makes a thorough review of the existing and well-established improved stability practises a power system benefits from through the implementation of a single FACTS device or HVDC link, and compares the case –and hence raises the issue–when all active components are integrated simultaneously and uncoordinatedly. System identification approaches are also in the core of this research, serving as means of reaching a linear state space model representative of the non-linear power system, which is a pre-requisite for LQG control design methodology.
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Xie, Hailian. "On Power-system Benefits, Main-circuit Design, and Control of StatComs with Energy Storage." Doctoral thesis, Stockholm : Skolan för elektro- och systemteknik, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10302.
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Lakomý, Marek. "Analýza provozu trakční napájecí stanice." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220948.
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The work analyzes the operation of hybrid substations. The first chapter provides an analysis of domestic traction systems and describes in detail specific station. The next chapter follows the first in a way in which obtained parameters are converted to parameters suitable for the simulation program and presents its results. The third chapter discusses the serial communication used in one switchgear and about voltage regulator that controls one high voltage field. The last chapter verifies the simulation results obtained from the second chapter with real measurement and direct comparison is also included.
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Dufernez, Bruno. "Étude et simulation numérique d'un cycloconvertisseur à commande entièrement numérique." Vandoeuvre-les-Nancy, INPL, 1992. http://www.theses.fr/1992INPL133N.
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Le travail présenté dans cette thèse a été réalisé au sein du groupe de recherches en électrotechnique et électronique de Nancy, en collaboration avec le centre de recherche en automatique de Nancy. Il s'agit d'une étude sur les cycloconvertisseurs et plus particulièrement sur la réalisation de la commande d'un cycloconvertisseur triphasé à 36 thyristors, entièrement numérique, sans courant de circulation et sans liaison de neutre. Cette commande numérique est basée sur un générateur d'impulsions de type allumeur à retard. L'étude a été réalisée principalement par simulation numérique. Le programme de simulation a été réalisé avec GASPE (générateur automatique de programme de simulation des procédés électromécaniques), en utilisant une méthode de modélisation permettant de prendre en compte toutes les topologies du convertisseur, en particulier les commutations avec empiétement. La comparaison entre les différentes stratégies de commande s'appuie sur l'observation des formes d'ondes et des taux d'harmoniques. L'ébauche d'une réalisation pratique d'un cycloconvertisseur monophasé, sans courant de circulation et entièrement numérique est aussi présentée
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Sechilariu, Manuela. "Utilisation des réseaux de Petri colorés et temporisés pour la modélisation et la simulation des montages redresseurs et onduleurs." Angers, 1993. http://www.theses.fr/1993ANGE0012.
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Ce mémoire montre la faisabilité d'une technique de commande des convertisseurs statiques, utilisant les réseaux de Petri (RDP). L'originalité de ce travail réside dans l'utilisation de RDP colorés et temporisés pour la modélisation. Deux exemples sont retenus. Le modèle du redresseur triphasé à thyristors est présenté de manière que l'on puisse analyser les valeurs de l'angle de retard d'allumage ; des temporisations de durées variables permettent de simuler la variation de la tension redressée. Le modèle de l'onduleur autonome évolue dynamiquement à la fréquence souhaitée ; le changement de la durée des temporisations associées aux transitions conduit au changement de la fréquence de sortie de l'onduleur. L'étude effectuée sur l'ensemble redresseur-onduleur machine-asynchrone nous permet d'envisager une stratégie de fonctionnement en vitesse de rotation variable, fondée sur une commande algorithmique des temporisations, conformément à l'asservissement donné. Nous avons réalisé une maquette de redresseur à thyristors liée à un ordinateur. La commande est gérée par RDP synchronisé. Elle ouvre des perspectives pour une nouvelle technique de commande des convertisseurs statiques.
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Melhem, Wissam. "Contribution à l'étude des onduleurs de tension à commutation douce destinés à le forte puissance." Cachan, Ecole normale supérieure, 1995. http://www.theses.fr/1995DENS0018.
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Le travail entrepris dans cette thèse permet d'analyser les possibilités de l'introduction de la commutation douce dans les onduleurs de tension a mli destines a la forte puissance. Une étude bibliographique conduit dans un premier temps à établir une classification des différentes structures proposées. L'analyse des avantages et inconvénients associes au fonctionnement de ces structures (contraintes, critères de fonctionnement en mli) nous amène à poursuivre notre étude sur deux structures de concepts différents: la première est qualifiée de structure a commutation mixte. Dans ce cas, l'instauration de la commutation douce est réalisée au niveau de chaque interrupteur élémentaire. Une étude approfondie de son fonctionnement a conduit a la mise en place d'une maquette expérimentale de forte puissance (1 kv, 1ka, 10 khz) qui a permis de justifier le recours a la commutation douce a travers des mesures comparatives avec la structure fonctionnant en commutation dure. La deuxième est qualifiée de structure à large ondulation. Dans ce cas, l'instauration de la commutation douce est assurée d'une façon commune à tous les bras de l'onduleur. Une modification du schéma de base de cette structure mène a optimiser ses conditions de fonctionnement. Une maquette expérimentale de moyenne puissance (500 v, 50 a, 20 khz) valide l'étude théorique. Un bilan des potentialités de cette technique de commutation clos notre rapport
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Labouré, Eric. "Contribution à l'étude des perturbations conduites dans les alimentations continu-continu isolées." Cachan, Ecole normale supérieure, 1995. http://www.theses.fr/1995DENS0010.
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Ce travail s'inscrit dans une démarche générale de réduction des perturbations électromagnétiques émises par les équipements électriques. Il s'agit d'étudier les perturbations conduites générées par les convertisseurs statiques haute fréquence moyenne puissance dans l'optique de réaliser un outil d'aide a la conception prenant en compte ces phénomènes. Notre étude utilise comme support deux alimentations continu-continu isolées (alimentation flyback et alimentation forward) représentatives des problèmes rencontres. Après un bref rappel sur les normes et sur les équipements correspondants, un capteur de courant adapte a l'étude des perturbations électromagnétiques dans les convertisseurs statiques est présenté. Un des objectifs de l'étude est de pouvoir prédéterminer par simulation le niveau de perturbations d'un convertisseur. Pour cela, il est nécessaire de disposer d'un modèle électrique pour chacun des ensembles qui le constitue. Les modèles développés dans ce document concernent le transformateur et les composants a semi-conducteur (diode et igbt). Afin que ces modèles soient simples et facilement intégrables a un logiciel de simulation de type circuit, des modèles comportementaux issus de la littérature sont utilises. Notre travail consiste à adapter ces modèles à notre étude, c'est à dire à obtenir une bonne représentation des composants dans la bande de fréquence 10khz-30mhz. Le comportement des alimentations flyback et forward est alors analyse, essentiellement par simulation. A partir d'un schéma élémentaire (composants idéaux) de l'alimentation, les différents éléments parasites sont ajoutes étape par étape. L'analyse des modifications observées dans le domaine temporel et fréquentiel permet de cerner les diverses origines des perturbations. Cette démarche est reprise avec l'introduction d'un écrêteur puis d'un calc non dissipatif. Les résultats obtenus par simulation sont compares aux résultats expérimentaux afin de valider l'ensemble de l'étude (modèles et résultats d'analyse). Enfin, divers moyens de reduction des perturbations sont analyses. Tout d'abord deux moyens de reduction a la source sont proposes. Puis diverses solutions de reduction des couplages sont présentées. Finalement, le filtrage est abordé et les diverses cellules usuelles sont étudiées et comparées
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Li, Jian Ming. "Evaluation des possibilités fréquentielles des transistors bipolaires de puissance haute tension." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0049.
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Cette étude vise les possibilités d'utilisation des T. B. P. H. T. Dans les convertisseurs à résonance à des fréquences de quelques centaines de kHz et des puissances de quelques dizaines de kw. Pour atteindre cet objectif, une modélisation analytique uni-dimensionnelle du semi-conducteur est proposée: elle permet d'obtenir les caractéristiques de la commande de base aux fréquences correspondantes et d'analyser les performances fréquentielles des circuits de base aux fréquences correspondantes et d'analyser les performances fréquentielles des circuits de base classiques. Les synthèses de commande et les interrupteurs du type “CASCODE” sont représentés. Deux convertisseurs à résonance réalisés, un onduleur de tension 200 kHz-10 kW et un onduleur de courant 100 kHz-20 kW montrent la faisabilité de l'objectif en optimisant la commande des T. B. P. H. T
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Pierfederici, Serge. "Contribution à l'étude de la stabilité de cascade de convertisseurs : application à la correction du facteur de puissance sur le réseau monophase." Vandoeuvre-les-Nancy, INPL, 1998. http://www.theses.fr/1998INPL073N.
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Ce mémoire traite du problème de la mise en cascade de convertisseurs en vue d'une application à la correction du facteur de puissance sur le réseau monophasé. Après avoir évoqué les différentes techniques utilisées dans la correction du facteur de puissance, deux approches vont être traitées. La première utilise les propriétés de la théorie des systèmes à structure variable pour générer la commande large signal d'une cascade boost-forward. La robustesse, un contrôle à fréquence fixe et un facteur de puissance quasi unitaire sont les principales caractéristiques de cette commande. La seconde utilise un développement limité au premier ordre, autour du point d'équilibre pour générer les commandes découplées de chaque étage d'une cascade de convertisseur. Cette méthode permet un parfait contrôle des grandeurs internes du système lors des divers régimes transitoires. Dans le cas d'une cascade boost-forward, l'interaction entre les deux techniques précédentes permet de cumuler leurs avantages respectifs. Des méthodes ont été proposées afin d'estimer les domaines de validité des commandes utilisées. Pour l'approche large signal et la commande par mode de glissement, l'étude du comportement du système au voisinage des surfaces de commutation permet de déterminer les domaines de l'espace d'état ou la stabilité au sens large signal est assurée. Pour l'approche petit signal, deux méthodes, applicables aux convertisseurs statiques et permettant d'estimer les domaines d'attraction stable autour d'un point de fonctionnement, ont été présentées.
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Enjalbert, Gérard. "Développement d'un outil de conception assistée par ordinateur : le logiciel circuit." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0095.
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Le but de ce travail est le développement d'un logiciel de CAO orienté vers l'étude de structures de convertisseurs statiques associés à leur environnement. Après une description complète du logiciel, tant sous l'aspect convivial que théorique, nous présentons un ensemble de modifications apportés au post-processeur afin de permettre à l'utilisateur d'étudier les grandeurs électriques qui l'intéresse (courants, tensions simples et composées, analyse harmonique, puissance, valeurs moyennes et efficaces. ,. ) L'implantation de la commande en Modulation de Largeur d'Impulsions met en évidence l'influence des limitations pratiques introduites dans la commande des interrupteurs. L'intégration de boucles de régulation ainsi que sa validation par la comparaison entre la simulation et un montage expérimental complète l'éventail des fonctions disponibles en permettant au logiciel de simuler le comportement d'un convertisseur dans un environnement
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Hounkonnou, Oussou Kassien. "Étude d'un nouveau type de machine synchrone autopilotée." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL116N.
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Un moteur synchrone triphase, est alimente en étoile par quatre transistors, trois d'entre eux assurent la fonction onduleur et un quatrième hache le courant par le neutre. Ce système permet d'autopilotage par mesure des tensions entre phases non alimentées. La simplicité de cette alimentation pose cependant des problèmes liés a la récupération d'énergie lors des commutations; les F. C. E. M. Des phases non alimentées peuvent débiter dans les circuits de récupération. L'objet principal de ce travail est la modélisation du fonctionnement du moteur alimenté avec différents circuits de récupération d'énergie. Une solution est décrite avec quelques applications pour des régions non alimentées par des réseaux classiques
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Rioual, Pascal. "Modélisation et commande d'un redresseur à MLI alimenté par un réseau déséquilibré." Cachan, Ecole normale supérieure, 1993. http://www.theses.fr/1993DENS0008.
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L'augmentation considérable ces dernières années du nombre de convertisseur sur le réseau d'alimentation se traduit par la nécessite de s'intéresser a la compatibilité entre les convertisseurs et le réseau. Le redresseur à mli est un convertisseur dont les caractéristiques lui permettent d'absorber des courants réseaux sinusoïdaux, et d'échanger de la puissance active et réactive avec le réseau. Le présent travail concerne l'étude de la modélisation et la commande de ce convertisseur ainsi que l'extension au cas d'un réseau déséquilibre. Le redresseur est contrôlé par une régulation cascade: des boucles internes régulent les courants réseaux, une boucle externe régule la tension de capacité. Les conséquences de l'apparition d'une perturbation de type creux de tension (distorsion harmonique sur les courants réseaux, oscillation a l'harmonique 2 des composantes continues) sont analysées puis simulées et vérifiées expérimentalement. Deux solutions sont étudiées: - une compensation s'appuyant sur une étude théorique du système. - la construction d'un régulateur robuste appliquant le principe du modèle interne de Wohnam et la méthode de placement de pôles par -stabilité. Les avantages obtenus permettent d'envisager une meilleure continuité de fonctionnement face aux creux de tension, un dimensionnement réduit du convertisseur, et la conservation des performances. Les domaines d'application concernes sont varies. Dans le domaine industriel, il s'agit des alimentations à bon facteur de puissance ou des procédés nécessitant le réglage du réactif
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Leplus, François. "Sur la modélisation numérique des transformateurs monophasé et triphasé : Application aux montages redresseurs et gradateurs." Lille 1, 1989. http://www.theses.fr/1989LIL10073.
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Méthode de résolution des équations du système modélisé, indépendante de son environnement électrique, donnant un programme modulaire, utilisable dans un ensemble plus complexe. Extension de la méthode et procédure d'identification des paramètres. Expérimentation en fonctionnement redresseur et gradateur
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Yan, Feng. "Contribution à la modélisation automatique sans à priori de commande des convertisseurs statiques." Paris, CNAM, 1993. http://www.theses.fr/1993CNAM0168.
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Dans le cadre de l'analyse automatique des convertisseurs statiques de puissance par ordinateur, ce travail propose une méthode systématique de modélisation sans à priori de commande par réseaux de pétri. Cette démarche basée sur l’hypothèse de composants idéalisés s'appuie d'abord sur le dénombrement des différentes configurations induites par les états binaires des interrupteurs en respectant les contraintes de commutation. Elle passe ensuite par l’écriture des réceptivités décrivant toutes les conditions de franchissement des transitions d'un graphe parallèle et enfin par la mise en équations des configurations réalisables en tenant compte des particularités topologiques de chacune d'elles. Le logiciel ainsi conçu, entièrement graphique, permet d’éditer facilement le schéma d'un convertisseur et d’établir son modèle de manière automatique. L'application présentée sur une alimentation à découpage en demi-pont comprenant les circuits d'aide a la commutation des transistors montre l’efficacité de la méthode et le logiciel développé
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Pascal, Jean-Pierre. "Etude de circuits d'aide à la commutation de thyristors GTO montés en série pour des applications à la traction ferroviaire." Paris 6, 1986. http://www.theses.fr/1986PA066273.
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Revue des propriétés des thyristors interrupteurs. Aptitude à l'utilisation en grande traction. Etude du rétablissement de la tension aux bornes. Soufflage et mise en série des thyristors interrupteurs. Caractérisation des GTO de grande puissance.
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Pahmer, Sueda Carmen M. "Contribution à l'étude de filtres actifs de puissance de type shunt : commande-simulation." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0080.
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Le travail presente consiste a etudier de maniere detaillee les algorithmes de commande d'un filtre actif de puissance de type shunt realise a partir d'un onduleur de tension connecte sur un reseau triphase de puissance finie. Ces algorithmes ont ete testes en simulation a l'aide du logiciel a usage general electro-magnetic transients program (emtp). A ce propos, cinq methodes distantes pour obtenir les courants de reference pour chaque phase de l'onduleur de tension ont ete formalises. De la meme maniere, la regulation de tension aux bornes du condensateur de cet onduleur a egalement ete abordee. Dans certains cas de figure la numerisation controle-commande a ete developpe de maniere a simuler des structures les plus proches possibles de la realite. Quelques resultats experimentaux obtenus a l'aide d'un filtre actif de commande numerique permettent de valider notre methodologie
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Bendjoua, Jamel. "Contribution à l'étude de l'alimentation des machines électriques de fortes puissances : minimisation des ondulations de couple lors de l'alimentation par cycloconvertisseur." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL119N.
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Ce travail porte sur la modélisation, la simulation, la commande du système cycloconvertisseur-machine synchrone et asynchrone et de la comparaison de leurs performances en terme d'ondulation de couple électromagnétique. On montre que la machine synchrone permet, en statique, d'avoir un couple moins ondulé. Par contre, la machine asynchrone présente un meilleur comportement dynamique lors du démarrage. Afin de limiter les harmoniques provoqués par le temps mort de sécurité, une deuxième horloge permettant d'imposer la durée du palier nul à une valeur fixe est proposée. Enfin, dans le but de réduire les ondulations du couple, une modification de la structure du cycloconvertisseur en ajoutant six thyristors de roue libre est étudiée. Cette modification a permis de réduire, d'une façon importante, les ondulations du couple de la machine synchrone fonctionnant à facteur de puissance unitaire
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Campos, Alexandre. "High performance static converters for series compensation of industrial power systems." Thesis, 1994. http://spectrum.library.concordia.ca/3409/1/NN97651.pdf.
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Pande, Manish. "Voltage controlled pulse width modulation pattern generators for static power converters." Thesis, 1993. http://spectrum.library.concordia.ca/5537/1/MM90807.pdf.
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Aduragba, Adebiyi Abayomi. "Investigating the application of Static Synchronous Compensator (STATCOM) for mitigating power transmission line losses." Thesis, 2017. http://hdl.handle.net/10321/2459.
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Submitted in fulfillment of the requirements for the degree of Master of Engineering in Electrical Power Engineering, Durban University of Technology, Durban, South Africa, 2017.Voltage instability and increased power loss on transmission lines are major challenges in power transmission due to ever increasing load growth. This work investigates the effect of Static Synchronous Compensator (STATCOM) to mitigate power losses and enhance the voltage stability of a transmission system. STATCOM, a shunt-connected power electronic device, operate as a Voltage Source Converter (VSC) to improve power transfer capacity of transmission lines by injecting a set of three-phase balanced sinusoidal current with controllable magnitude and phase angle into the transmission lines to regulate the line voltage and compensate for reactive power at the Point of Common Coupling (PCC). To validate the capacity of STATCOM in this light, a modified model of IEEE 14 bus test system was simulated using DIgSILENT PowerFactory v15. Four different load profiles were included by increasing the base load in a step of 10%. In each case, power flow was run with and without STATCOM incorporated in the network with a view to determine the impact of STATCOM on bus voltage and transmission line losses. The simulation results are obtained were recorded and analyzed. It is noted that there was sufficient improvement in the new voltage profile obtained for the weak buses of the system, the active and reactive power losses were mitigated by 17.73% and 24.80% respectively when STATCOM was incorporated at normal load. The results showed that STATCOM could give quick voltage support to reduce the likelihood of voltage collapse and mitigate power losses along the transmission lines. Reduction of reactive power losses along the lines is higher than the active power losses resulting in the improvement of the voltage profile as the device is connected to the system.
M
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Sivaprasad, Sreenivasa J. "Control, Modulation and Testing of High-Power Pulse Width Modulated Converters." Thesis, 2013. http://etd.iisc.ernet.in/2005/3310.
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Experimental research on high-power converters, particularly in an academic environment, faces severe infrastructural constraints. Usually, power source and loads of required ratings are not available. Further, more importantly, the energy consumption is huge. One possibility is to establish an experimental research platform, comprising of a network of high-power converters, through which power is circulated and which draws only the losses from the mains.
This work deals with the establishment of a circulating power test set-up, comprising of two line-side PWM converters, inclusive of control and modulation methods for the two converters. Two types of circulating power test setups are developed. In the first setup, the converters are connected in parallel, on ac as well as dc sides, such that real and/or reactive power is circulated between them. In the second test setup, the dc buses of the converters are separated; hence, only reactive power circulation is possible. These setups are used to conduct heat-run tests with low energy expenditure on the PWM converters at various operating conditions up to power levels of 150 kVA. Further, these are used to validate analytically-evaluated thermal characteristics of high-power PWM converters. A safe thermal limit is derived for such converters in terms of apparent power (kVA) handled, power factor and switching frequency. The effects of voltage sag and of unequal current sharing between parallel IGBT modules on the safe thermal limit are studied.
While the power drawn by the circulating-power setup from the grid is much lower than the ratings of the individual converters, the harmonic injection into the mains by the setup could be significant since the harmonics drawn by both converters tend to add up. This thesis investigates carrier interleaving to improve the waveform quality of grid current, drawn by the circulating-power test setup. The study of carrier interleaving is quite general and covers various applications of parallel-connected converters such as unity power factor rectification, static reactive power compensation and grid-connected renewable energy systems.
In literature, carrier interleaving has been employed mainly for unity power factor rectifiers, sharing a common dc load equally. In such case, the fundamental components of the terminal voltages of the parallel converters are equal. However, when the power sharing between the two converters is unequal, or when power is circulated between the two converters, the terminal voltages of the two converters are not equal. A method to estimate rms grid current ripple, drawn by parallel-connected converters with equal and/or unequal terminal voltages, in a synchronous reference frame is presented. Further, the influence of carrier interleaving on the rms grid current ripple is studied. The optimum interleaving angle, which minimizes the rms grid current ripple under various applications, is investigated. This angle is found to be a function of modulation index of the converters in the equal terminal voltages case. In the unequal terminal voltages case, the optimum interleaving angle is shown to be a function of the average modulation index of the two parallel converters.
The effect of carrier interleaving is experimentally studied on the reactive power circulation setup at different values of kVA and different dc bus voltages. The grid current ripple is measured for different values of interleaving angle. It is found experimentally that the optimum interleaving angle reduces the rms grid current ripple by between 37% and 48%, as compared without interleaving, at various operating conditions.
Further, the reactive power circulation test set-up is used to evaluate and compare power conversion losses corresponding to different PWM techniques such as conventional space-vector PWM (CSVPWM), bus-clamping PWM (BCPWM) and advanced bus-clamping PWM methods for static reactive power compensator (STATCOM) application at high power levels. It is demonstrated theoretically as well as experimentally that an advanced bus-clamping PWM method, termed minimum switching loss PWM (MSLPWM), leads to significantly lower power conversion loss than CSVPWM and BCPWM techniques at a given average switching frequency.
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WU, YUN-HUAN, and 吳昀寰. "Low Static Power DC-DC Converter for Car Application." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/fyu28k.
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Wang, Te-An, and 王得安. "Low-Power Area-Efficient Data Format Converter Design Using Static Register Allocation." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/07749599412681380830.
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碩士國立交通大學
資訊科學與工程研究所
96
In this thesis, we explore one low power and area efficient register allocation algorithm for data format converter (DFC) architecture designs. The proposed static register allocation (SRA) approach not only minimizes the power and number of register transitions, but also achieves a comparable area cost for DFC designs. From the implementation results of 16-bit 3x3, 4x4, 16x16 transposer, and IIR filter benchmarks using 1-D SRA, the power consumption can be alleviated by 27.4%, 45.3%, 50.2% and 25.7% respectively, compared with the SSRA design in 0.18 um CMOS process. The core area reduction by 44.6%, 51%, 53.9% and 38% can be achieved for the same cases. From the implementation results of 16-bit 1-D DWT, Zigzag scanner and 4x4 par-transposer benchmarks using 2-D SRA, the power consumption can be alleviated by 5.3%, 13.6% and 16.1%, respectively, compared with the SSRA design in 0.18 um CMOS process. The core area reduction by 28.9%, 33.6% and 26.4% can be achieved for the same cases. Thus, the proposed SRA-based design has lowest power consumption and cost effective among the several approaches. Finally, we implement the interleaver using SRA for WiMAX system.
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Freire, Diogo Filipe Martins. "Multi-Level Converter with Predictive Control for Power Conditioning." Master's thesis, 2018. http://hdl.handle.net/10316/86563.
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Dissertação de Mestrado Integrado em Engenharia Electrotécnica e de Computadores apresentada à Faculdade de Ciências e TecnologiaA estabilidade de tensão e o controlo do factor de potência são dois pontos-chave na operação em regime permanente dos sistemas eléctricos. O static synchronous compensator e o seu sistema de controlo podem ser usados para melhorar o desempenho do sistema energia. Neste trabalho é usado um controlador preditivo com uma nova abordagem de geração de referências e que permite compensar a potência reactiva necessária para manter um fator de potência escolhido no final da linha de transmissão. Os resultados da simulação demonstram que a estratégia de controlo proposta melhora o fator de potência e estabiliza a tensão no final da linha de transmissão. Para avaliar o desempenho do método de controlo proposto, foi simulada uma rede de distribuição de 10kV. Para testar experimentalmente o desempenho do método de controlo proposto, foi construído um protótipo de um conversor trifásico Neutral-Point-Clamped de cinco níveis. O teste experimental foi realizado num nível de tensão inferior, com 130V. Para se ter uma melhor base de comparação foi simulado um sistema mais próximo do realizado experimentalmente. Os resultados obtidos são muito semelhantes, mas não tão perfeitos como nos testes feitos no primeiro sistema simulado (rede de distribuição de 10kV). Isto pode ser justificado pelo elevado tempo de amostragem que teve de ser usado para que o processador de sinal digital pudesse computar toda a informação, mas também pode ser justificado pelas baixas correntes com que o sistema foi testado.
Voltage stability and power factor control are two key points in the steady-state operation of electrical systems. The static synchronous compensator and its control system can be used to improve the performance of the energy system. In this work, a predictive controller model with a new reference generation approach is used. It compensates the reactive power required to maintain a chosen power factor at the end of the transmission line. To evaluate the performance of the proposed control method, a 10kV distribution network was examined in simulation. Simulation results demonstrate that the proposed control strategy improves the power factor and stabilize the voltage at the Point of Common Coupling. The results of the simulation also demonstrate that the proposed control strategy improves the power factor and stabilizes the voltage at the end of the transmission line. To evaluate the performance of the proposed control method, a 10kV distribution network was simulated. In order to experimentally test the performance of the proposed control method, a prototype of a five-phase three-phase Neutral-Point-Clamped converter was constructed. The experimental test was performed at a voltage level of less than 130V. In order to have a better basis of comparison, a simulation system was simulated that was closer to the experimental one. The results are very similar, but not as perfect as in the tests done in the first simulated system (10 kV network). This can be justified by the high sampling time that had to be used so that the digital signal processor could compute all the information but could also be substantiated by the low currents that the system was tested.
FCT
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Maturu, Suresh. "Performance Evaluation Of Distance Relays For FACTS Compensated Transmission Lines." Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2084.
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With limited enhancement or expansion of the transmission infrastructure, the contemporary power systems are operating under more stressed conditions. It becomes important to fully utilize the existing transmission system to supply load demand as much as possible, thus eliminating or reducing the need for new transmission investment.
Flexible AC Transmission System (FACTS) technology provides an alternative to fully utilize the existing transmission lines as well as new and upgraded lines, by controlling power and also enhancing the power transfer capability of transmission lines. However, the implementation of FACTS controllers in the transmission system has introduced new power system dynamics that must be addressed in the area of power system protection, such as rapid changes in line impedance, power angle, line currents, transients introduced by the occurrence of fault and associated control action of the FACTS controller. Therefore, the performance of the protection system must be carefully analyzed in the presence of FACTS controllers.
The thesis aims at evaluating the performance of distance relays when different types of FACTS controllers, in particular Voltage Source Converter (VSC) based FACTS controllers, are incorporated at the midpoint of the transmission system to achieve voltage profile improvement and power transfer capability. The detailed models of these controllers and their control strategies are described. The presence of FACTS controllers in the loop affects both steady state and transient components of voltage and current signals. The rapid response of FACTS controllers to different power system configurations significantly affects the apparent impedance seen by distance relays. The apparent impedance seen by distance relays would be different from that of the system without FACTS controller. Due to this, the distance relay may malfunction, resulting in unreliable operation of the power system during faults. Furthermore, the effect of FACTS controllers on distance relay operation depends on the type of FACTS controller used, the application for which it has been installed and its location in the power system. The distance relay is evaluated for different loading conditions and for various fault conditions. Simulation studies are carried out using PSCAD/EMTDC based transient simulation package.