Made available in DSpace on 2015-03-03T15:07:34Z (GMT). No. of bitstreams: 1 AndreFOAD_DISSERT.pdf: 2002320 bytes, checksum: 0ebf2e7fb75a8ce59284dc72a43ef7ba (MD5) Previous issue date: 2012-05-18 / The separation methods are reduced applications as a result of the operational costs, the low output and the long time to separate the uids. But, these treatment methods are important because of the need for extraction of unwanted contaminants in the oil production. The water and the concentration of oil in water should be minimal (around 40 to 20 ppm) in order to take it to the sea. Because of the need of primary treatment, the objective of this project is to study and implement algorithms for identification of polynomial NARX (Nonlinear Auto-Regressive with Exogenous Input) models in closed loop, implement a structural identification, and compare strategies using PI control and updated on-line NARX predictive models on a combination of three-phase separator in series with three hydro cyclones batteries. The main goal of this project is to: obtain an optimized process of phase separation that will regulate the system, even in the presence of oil gushes; Show that it is possible to get optimized tunings for controllers analyzing the mesh as a whole, and evaluate and compare the strategies of PI and predictive control applied to the process. To accomplish these goals a simulator was used to represent the three phase separator and hydro cyclones. Algorithms were developed for system identification (NARX) using RLS(Recursive Least Square), along with methods for structure models detection. Predictive Control Algorithms were also implemented with NARX model updated on-line, and optimization algorithms using PSO (Particle Swarm Optimization). This project ends with a comparison of results obtained from the use of PI and predictive controllers (both with optimal state through the algorithm of cloud particles) in the simulated system. Thus, concluding that the performed optimizations make the system less sensitive to external perturbations and when optimized, the two controllers show similar results with the assessment of predictive control somewhat less sensitive to disturbances / Os m?todos de separa??o de ?leo e ?gua possuem, em sua maioria, aplica??es reduzidas devido ao custo operacional, a baixa efici?ncia de separa??o e ao alto tempo de processamento da separa??o. Por?m, Esses m?todos de tratamento s?o importantes devido a necessidade de extra??o dos contaminantes mais indesejados no processo de produ??o do petr?leo, a ?gua, e ao mesmo tempo, a concentra??o de ?leo na ?gua deve ser m?nima (da ordem de 40 a 20ppm) para o descarte regular da fase aquosa ao mar. A partir dessa necessidade de tratamento prim?rio objetiva-se, neste trabalho, estudar e implementar algoritmos de identifica??o para modelos polinomiais NARX em malha fechada, detectando a estrutura dos modelos, e comparar estrat?gias de controle PI e preditivo utilizando os modelos NARX (Nonlinear Auto-Regressive with Exogenous Input) atualizados online em uma combina??o de separador trif?sico em s?rie com tr?s baterias de hidrociclones. Os objetivos principais deste trabalho s?o obter um processo otimizado de separa??o trif?sica que regule o sistema, mesmo na presen?a de golfadas; mostrar que e poss?vel obter sintonias otimizadas para os controladores analisando a malha como um todo; e, avaliar e comparar as estrat?gias de controle PI e preditivo aplicadas ao processo. Para cumprir estes objetivos foi utilizado um simulador para representar o separador trif?sico e os hidrociclones, al?m de desenvolvidos algoritmos de identifica??o de sistemas (NARX) utilizando MQR (M?nimos Quadrados Recursivo), aliados a m?todos de detec??o de estrutura de modelos. Tamb?m foram implementados algoritmos de controle preditivo com modelos NARX atualizados online, e algoritmos de otimiza??o que utilizam PSO (Particle Swarm Optimization). O trabalho finaliza com a compara??o de resultados obtidos a partir da utiliza??o dos controladores PI e preditivo no sistema simulado ambos com par?metros otimizados atrav?s do algoritmo de nuvem de part?culas, e concluindo que as otimiza??es realizadas tornam o regulat?rio menos sens?vel a perturba??es externas (golfadas) e quando otimizados os dois controladores apresentam resultados similares, sendo os resultados do preditivo um pouco menos sens?vel as perturba??es

Made available in DSpace on 2014-12-17T14:56:02Z (GMT). No. of bitstreams: 1 FranciscoCSJ.pdf: 396492 bytes, checksum: c7b91bb21a15450749eb2738a17c2f3e (MD5) Previous issue date: 2005-07-28 / There are two main approaches for using in adaptive controllers. One is the so-called model reference adaptive control (MRAC), and the other is the so-called adaptive pole placement control (APPC). In MRAC, a reference model is chosen to generate the desired trajectory that the plant output has to follow, and it can require cancellation of the plant zeros. Due to its flexibility in choosing the controller design methodology (state feedback, compensator design, linear quadratic, etc.) and the adaptive law (least squares, gradient, etc.), the APPC is the most general type of adaptive control. Traditionally, it has been developed in an indirect approach and, as an advantage, it may be applied to non-minimum phase plants, because do not involve plant zero-pole cancellations. The integration to variable structure systems allows to aggregate fast transient and robustness to parametric uncertainties and disturbances, as well. In this work, a variable structure adaptive pole placement control (VS-APPC) is proposed. Therefore, new switching laws are proposed, instead of using the traditional integral adaptive laws. Additionally, simulation results for an unstable first order system and simulation and practical results for a three-phase induction motor are shown / Existem dois m?todos principais para a constru??o de controladores adaptativos. Um deles ? o controle adaptativo por modelo de refer?ncia (MRAC) e o outro ? o controle adaptativo por posicionamento de p?los (APPC). No MRAC, um modelo de refer?ncia ? escolhido para gerar a trajet?ria desejada que o sinal de sa?da da planta deve seguir, e ele pode requerer o cancelamento de zeros da planta. Devido a sua flexibilidade em escolher a metodologia de projeto do controlador (realimenta??o de estado, projeto de compensador, linear quadr?tico, etc.) e a lei adaptativa (m?nimos quadrados, m?todo do gradiente, etc.), o APPC ? o tipo mais geral de controle adaptativo. Tradicionalmente, vem sendo desenvolvido em uma abordagem indireta e, como uma vantagem, pode ser aplicado a plantas de fase n?o-m?nima, j? que n?o envolve cancelamentos de zeros e p?los. A integra??o aos sistemas com estrutura vari?vel permite agregar rapidez no transit?rio e robustez ?s varia??es param?tricas e perturba??es. O objetivo deste trabalho ? desenvolver um controlador adaptativo por posicionamento de p?los e estrutura vari?vel (VS-APPC). Portanto, s?o propostas leis chaveadas em substitui??o ?s leis adaptativas integrais tradicionais. Adicionalmente, s?o apresentadas simula??es para uma planta de primeira ordem inst?vel, assim como simula??es e resultados pr?ticos da aplica??o da t?cnica proposta a um motor de indu??o trif?sico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work has for motive to obtain the project and build of an assymmetrical three-phase induction generator connected to single-phase supply system, in order to be used in rural areas. This equipment has been presented as a better alternative in relation the others proposed more commercialized at the moment, due to its robustness, low cost, less maintenance requirements and excellent performance. Firstly, in the theoric part concerned to the system it is presented a mathematical representation, frequency domain mathematical model, whose equations are performed in function of an unbalance factor in order to obtain balance three-phase voltages in the system. Then, some simulations are performed in the simulator that was developed in the Microsoft Excel program. From these implements, it is carried out study cases to prove the assymmetrical three-phase induction generator use potentialities. A prototype is projected and built, which experimental results are compared to the computer result. / O objetivo deste trabalho é obter o projeto e a construção de um gerador de indução trifásico assimétrico conectado a um sistema de distribuição de energia elétrica monofásica; visando aplicá-lo em áreas rurais. Este dispositivo, em face de sua robustez, baixo custo, menores requisitos de manutenção e bom desempenho, consiste numa alternativa bastante atrativa em relação às outras propostas existentes atualmente. O estudo teórico inicia-se através da elaboração de uma modelagem matemática para o sistema, no domínio da freqüência, cujas equações são colocadas em função de um fator indicativo do nível de desbalanceamento, visando à obtenção de tensões balanceadas na carga. Para tanto, a modelagem matemática elaborada é implementada num simulador desenvolvido no programa Microsoft Excel. A partir desta implementação, são efetuados estudos de casos no sentido de evidenciar as potencialidades do gerador assimétrico conectado a cargas rurais. Os trabalhos computacionais são devidamente validados à luz de resultados experimentais extraídos de um protótipo de equipamento concebido, projetado e construído para fins deste trabalho. / Mestre em Ciências

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-10-06T12:04:38Z No. of bitstreams: 2 Dissertação - Lázaro Rubens Araújo Pinto - 2017.pdf: 16272237 bytes, checksum: 9f3d1693d0282cbf28a35702c1a9cf17 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-10-06T12:04:51Z (GMT) No. of bitstreams: 2 Dissertação - Lázaro Rubens Araújo Pinto - 2017.pdf: 16272237 bytes, checksum: 9f3d1693d0282cbf28a35702c1a9cf17 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-10-06T12:04:52Z (GMT). No. of bitstreams: 2 Dissertação - Lázaro Rubens Araújo Pinto - 2017.pdf: 16272237 bytes, checksum: 9f3d1693d0282cbf28a35702c1a9cf17 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work proposes an analysis of the closed-loop operation of a distributed generation system connected to a three-phase four-wire AC power system by a three-phase four-leg inverter. The modulation strategy adopted for this inverter is determined by the Model Predictive Control (MPC) method. Reasons for the use of this topology and the control method are discussed. The chosen structure for the MPC predictive control aims to supply of active and reactive power by the inverter in order to maximize the power factor measured by the four-wire AC source (Y-n). Four possible cases of operation are reported for the analysis of the proposal in the three-phase four-leg inverter and other two cases for a three-phase full-bridge inverter (3F) for comparison purposes. Based on the monitoring of the active powers involved and the other variables of interest, it was possible to exemplify the achievement of the proposed objectives and validate the adopted method, at least under modeling and software simulation level. / Este trabalho propõe uma análise da operação em malha fechada de um sistema de geração distribuída para conexão em um sistema trifásico a quatro fios, a partir do controle de um inversor trifásico a quatro braços. A estratégia de modulação adotada para este inversor é determinada pelo método de controle preditivo baseado em modelo (MPC - Model Predictive Control). Justificativas para a utilização dessa topologia e do método de controle são discutidas. A estrutura escolhida para o controle preditivo MPC objetiva o fornecimento de potência ativa e reativa pelo inversor tendo em vista a maximização do fator de potência medido a partir da fonte pela fonte CA a quatro fios (Y-n). Quatro casos são abordados para análise da proposta no inversor trifásico a quatro braços e dois casos para um inversor trifásico em ponte completa (3F) para efeito de comparação. Baseando-se no monitoramento das potências elétricas envolvidas e nas demais grandezas de interesse, foi possível concluir que os resultados de simulações exemplificam o alcance dos objetivos propostos e validam o método adotado, pelo menos em relação à modelagem matemática empregada e à simulação do sistema de geração proposto em ambiente computacional.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-25T18:26:00Z No. of bitstreams: 1 ricardovioldossantos.pdf: 2585437 bytes, checksum: 897e63c2118d5c0e74581bbdb80ccb38 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-26T12:23:14Z (GMT) No. of bitstreams: 1 ricardovioldossantos.pdf: 2585437 bytes, checksum: 897e63c2118d5c0e74581bbdb80ccb38 (MD5) / Made available in DSpace on 2017-04-26T12:23:14Z (GMT). No. of bitstreams: 1 ricardovioldossantos.pdf: 2585437 bytes, checksum: 897e63c2118d5c0e74581bbdb80ccb38 (MD5) Previous issue date: 2015-08-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Buscando corrigir aspectos relacionados à qualidade de energia, bancos de capacitores em derivação são utilizados em alimentadores primários dos sistemas de distribuição. A busca pela melhor forma de alocação constitui um problema complexo de natureza matemática combinatória, ao incluir critérios técnicos conflitantes e restrições do sistema. Este problema não tem solução trivial, tornando-se importante a formulação de metodologias para auxiliar nessa tarefa. Neste trabalho, é proposta uma metodologia para alocação de bancos de capacitores em derivação em nós do sistema elétrico, com possibilidade de alocação desequilibrada, considerando sua natureza discreta, com objetivo de minimizar desequilíbrios de tensão e custos de alocação, baseada em aplicação de algoritmo genético. Foram consideradas também restrições tais como limites de correntes nos alimentadores, limites de tensão para a conformidade com as faixas adequadas de tensão padronizadas pelos órgãos competentes e a disponibilidade de bancos. / Seeking for correcting issues related to power quality, shunt capacitor banks are used in primary feeders of distribution systems. The search for the best allocation is a complex problem of combinatorial mathematical nature, including conflicting technical criteria and constraints of the system. This problem has nontrivial solution, making important the development of methodologies to assist in this task. In this work, it is proposed a methodology for allocation of shunt capacitor banks in electric system nodes, with the possibility of unbalanced allocation, considering its discrete nature, with the purpose of minimizing voltage imbalances and allocating costs, based on genetic algorithm application. Restrictions such as limits of current feeders, voltage limits for compliance with the appropriate standard voltage ranges and the availability of capacitor banks were considered.

The extensive use of nonlinear loads in today’s world has inspired considerable research interest in the area of power quality improvement. This thesis proposes an integrated magnetics based compact solution which provides regulated, balanced and sinusoidal load voltage drawing sinusoidal and balanced currents from the grid. Thus, it supplies clean power to the load without polluting the grid. It consists of an EI shaped magnetic core and two compensators known as the series and shunt compensators. The series compensator ensures the quality of output voltage, where as the shunt one takes care of quality of the current drawn from the grid. The magnetic circuit acts as a common domain for interaction between the energy ports. It also provides galvanic isolation between the inverters, load and the grid. The magnetic circuit incorporates a virtual arm switching mechanism to have an option of connecting the inverters either in series or in parallel with each other depending on the requirements. During normal mode when the switch remains inactive, the series inverter is effectively in series with the load and the shunt inverter is effectively connected across the load. Therefore, the voltage source inverters can be independently controlled to serve the purpose of series and shunt compensation. The shunt inverter is always connected in shunt with the grid. The magnetic arm switch is activated during grid power failure. Then the switch ensures parallel connection of the inverters and the load. The inverters are controlled to share the load power according to the respective ratings. Thus the magnetic arm switching mechanism helps in improving the system reliability. The series inverter also can be connected in parallel with the shunt one in presence of the grid to supplement the shunt inverter by supplying harmonic and reactive currents. The design, modelling and implementation issues for single phase applications are considered first. A simple controller structure for this application is also discussed in the thesis. The individual compensation actions are then verified by simulation and experimental results. The three phase power quality compensator is in principle an extension of the single phase quality power supply. It is realized by combining three single phase units with minor modification in terms of windings. A more compact structure is also proposed wherein a single integrated magnetic circuit for the three phase application can be used. The composite magnetic circuit is modelled and designed considering a laboratory prototype. A synchronously rotating reference frame based controller structure for the series and shunt compensators are discussed. The control of the inverters in power sharing mode (with parallel connected inverters) are also proposed and discussed. Experimental and simulated results are presented to verify and validate the operation of this compensator in different operating modes. An effective improvement in the control dynamics is achieved for handling unbalanced and nonlinear loading without increasing inverter switching frequency and controller parameters. In other words, the modified control scheme can handle nonlinear and unbalanced loading with relatively slow proportional integral (PI) controllers. Suitable feed forward compensation terms corresponding to each harmonic component are added to the output of the PI controllers in order to achieve this effective improvement. Experimental results show good improvement in this regard (for both series and shunt compensations).

Os motores de indução desempenham um importante papel na indústria, fato este que destaca a importância do correto diagnóstico e classificação de falhas ainda em fase inicial de sua evolução, possibilitando aumento na produtividade e, principalmente, eliminando graves danos aos processos e às máquinas. Assim, a proposta desta tese consiste em apresentar um multiclassificador inteligente para o diagnóstico de motor sem defeitos, falhas de curto-circuito nos enrolamentos do estator, falhas de rotor e falhas de rolamentos em motores de indução trifásicos acionados por diferentes modelos de inversores de frequência por meio da análise das amplitudes dos sinais de corrente de estator no domínio do tempo. Para avaliar a precisão de classificação frente aos diversos níveis de severidade das falhas, foram comparados os desempenhos de quatro técnicas distintas de aprendizado de máquina; a saber: (i) Rede Fuzzy Artmap, (ii) Rede Perceptron Multicamadas, (iii) Máquina de Vetores de Suporte e (iv) k-Vizinhos-Próximos. Resultados experimentais obtidos a partir de 13.574 ensaios experimentais são apresentados para validar o estudo considerando uma ampla faixa de frequências de operação, bem como regimes de conjugado de carga em 5 motores diferentes. / Induction motors play an important role in the industry, a fact that highlights the importance of correct diagnosis and classification of faults on these machines still in early stages of their evolution, allowing increase in productivity and mainly, eliminating major damage to the processes and machines. Thus, the purpose of this thesis is to present an intelligent multi-classifier for the diagnoses of healthy motor, short-circuit faults in the stator windings, rotor broken bars and bearing faults in induction motors operating with different models of frequency inverters by analyzing the amplitude of the stator current signal in the time domain. To assess the classification accuracy across the various levels of faults severity, the performances of four different learning machine techniques were compared; namely: (i) Fuzzy ARTMAP network, (ii) Multilayer Perceptron Network, (iii) Support Vector Machine and (iv) k-Nearest-Neighbor. Experimental results obtained from 13.574 experimental tests are presented to validate the study considering a wide range of operating frequencies and also load conditions using 5 different motors.

The master’s thesis deals with design and realization of three-phase inverter for experimental high speed asynchronous motor with a mechanical power of 6 kW. The thesis deals with the design of the individual components of the DC link. The thesis describes the selection of suitable capacitors in the DC link. There is also a complete simulation of the inverter in the Matlab Simulink program. Part of the thesis is also the design and realization of printed circuit boards of this inverter.

The thesis deals with a concept of turning a conventional petrol powered lawn mower to a battery powered solution which is powered by lithium cells. A division to three chapters, comparison, mechanical and electrical, provides fluency of the whole design and further realization. The arrangement of chapters is performed so that the continuity of the thesis is maintained. Calculations of parameters of every motor and transmission with choosing particular devices are just a part of much interesting information which can be found in this thesis. All new components have full documentation except those which were changed during manufacturing. The electrical part explains every part of the schematics in detail. The realization contains difference between preliminary design and further production, manufacturing of the PCB and powering up the motor drives. The last part of the thesis contains temperature measurements of the device at no load.

This thesis deals with the asynchronous engines, describes their structure, principles, properties, use, and briefly describes the design of three-phase asynchronous motor. The first section describes the most common three-phase induction motor, the emergence of the rotating magnetic field and the basic relationships. The second part deals with asynchronous motors for specific applications, their design and features. The next section is an analysis engine borrowed from the electric company ATAS Náchod, and The last section lists ways to improve the basic parameters of induction motors designed and optimized engine.