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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Controle multivariável aplicado a uma coluna de destilação propano-propeno utilizando a técnica de separações de sinais / Multivariable control applied to a distillation column propane-propene utilizing the technique of signal separation.

ALVES, Alain Charles de Melo. 12 April 2018 (has links)
Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-04-12T14:56:31Z No. of bitstreams: 1 ALAIN CHARLES DE MELO ALVES - DISSERTAÇÃO (PPGEQ) 2017.pdf: 2958576 bytes, checksum: da6d8a9342aea19b0bd4eb2403563d7c (MD5) / Made available in DSpace on 2018-04-12T14:56:31Z (GMT). No. of bitstreams: 1 ALAIN CHARLES DE MELO ALVES - DISSERTAÇÃO (PPGEQ) 2017.pdf: 2958576 bytes, checksum: da6d8a9342aea19b0bd4eb2403563d7c (MD5) Previous issue date: 2017-02-17 / Capes / Os processos indústrias em sua maioria são multivariáveis e apresentam uma grande interação entre suas variáveis. A fim de reduzir essas interações algumas técnicas têm sido desenvolvidas. Análise de Componentes Independentes (ICA) tem sido uma técnica bastante promissora quando se deseja reduzir ou até mesmo eliminar o acoplamento entre as variáveis. Essa técnica é usada na separação de fontes desconhecidas. Embora já existam diversos trabalhos recentes sobre a aplicação do ICA em processos industriais, poucos são voltados para aplicação da técnica em colunas de destilação. Este trabalho estabelece uma estratégia de controle aplicado a uma coluna de destilação de alta pureza com recompressão de vapor utilizando o ICA. Além disso, o trabalho estabeleceu uma estratégia de controle para as composições de base e topo. Para tanto foi feita uma comunicação entre o Aspen Plus DynamicsTM e o Simulink/Matlab®. A comunicação foi estabelecida por meio do bloco AMSimulation. Duas estratégias de controle foram comparadas: MPC com o ICA e MPC sem o ICA. Os resultados da estratégia MPC com ICA se apresentaram mais promissoras mostrando que a técnica ICA é uma ferramenta desacoplante útil para sistemas com forte acoplamento. / The industrial processes are in its majority are multivariable and show a high number of interactions between its variables. Some techniques have been developed to target the reduction of these interactions. Independent Component Analysis (ICA) has been a very promising technique when it is desired to reduce or even eliminate the coupling between variables. The ICA technique has been utilized on the separation of unknown sources. Although there are several different studies targeting the application of ICA in industrial processes, just a few of them geared for technical applications in distillation columns. This dissertation attempts to establish a control strategy applied to a high purity distillation column with vapor recompression using the ICA. In addition, the dissertation proposes to establish a control strategy for the bottom and top of compositions. For this will be a communication between the Aspen Plus DynamicsTM and Simulink / Matlab®. The communication will be established through the AMSimulation block. Two control strategies were compared: MPC with ICA and MPC without MPC. The results of the MPC with ICA strategy were shown to be more promising, showing that the ICA technique is a useful decoupling tool for systems with strong coupling.
2

Modelagem, análise e experimentação de sistema fotovoltaico isolado baseado em plataforma de simulação com diagrama de blocos.

Santos Junior, Francisco Antonio Ferreira dos 29 February 2016 (has links)
Submitted by Morgana Silva (morgana_linhares@yahoo.com.br) on 2016-07-26T18:10:50Z No. of bitstreams: 1 arquivototal.pdf: 2752063 bytes, checksum: 886fc73f7f66099f1e033937798f6b7e (MD5) / Made available in DSpace on 2016-07-26T18:10:50Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2752063 bytes, checksum: 886fc73f7f66099f1e033937798f6b7e (MD5) Previous issue date: 2016-02-29 / This paper presents a block diagram modeling of a grid-independent photovoltaic power generation system, including the steps of DC regulation, voltage inversion, and control system based on dynamic simulations in Simulink / Matlab® exclusively using the built-in blocks available in its library. A well-known technique in literature called MPPT (maximum power point tracking) was used for tracking the maximum power of the photovoltaic generation. However, the control that was used to maintain a constant output voltage of the Push-Pull is based on a method that is similar to the MPPT, which configures a novelty of this research. The integration of modeling the entire PV system with these control systems is carried out in Simulink for investigaton and production of simulation results. An experimental platform that includes an emulator of photovoltaic panels, a 1 kW Push-Pull converter, a three-phase inverter with three arms and a hydraulic load constituided by a motor-pump was built in the laboratory. The experimental results corroborate the methodology that was used. / Este trabalho apresenta uma modelagem em diagramação de blocos de um sistema de geração de energia fotovoltaico isolado, incluindo as etapas de regulação CC, inversão de tensão e sistema de controle com base em simulações dinâmicas no ambiente Simulink/Matlab® utilizando, exclusivamente, os blocos built-in disponíveis em sua biblioteca. Uma técnica bem conhecida na literatura foi utilizada para o rastreio da máxima potência da geração fotovoltaica. No entanto, o controle utilizado para manter a tensão de saída constante do Push-Pull é baseado num método similar ao do rastreio da máxima potência, o que configura uma novidade deste trabalho. A integração da modelagem de todo o sistema fotovoltaico com estes sistemas de controle é realizada no ambiente Simulink para averiguação e produção dos resultados de simulação. Uma plataforma experimental que inclui um emulador de painéis fotovoltaicos, um Push-Pull de 1 kW de potência, um inversor trifásico de três braços e uma carga hidráulica constituída por um motobomba foi construída em laboratório. Os resultados experimentais corroboram a metodologia utilizada.
3

Δυναμική συμπεριφορά απαγωγέων υπερτάσεων

Νασιοπούλου, Χρυσούλα 16 June 2011 (has links)
Το θέμα της παρούσας διπλωματικής εργασίας είναι η μελέτη της συμπεριφοράς απαγωγέων υπερτάσεων (SPD), όταν αυτοί αποτελούν μέρος του εσωτερικού συστήματος αντικεραυνικής προστασίας για μια οικιακή εγκατάσταση. Αρχικά γίνεται μια αναφορά στα αίτια δημιουργίας κρουστικών υπερτάσεων στο δίκτυο διανομής, ενώ στη συνέχεια δίνεται έμφαση στις υπερτάσεις που προκαλούνται από άμεσα ή έμμεσα κεραυνικά πλήγματα στο σύστημα. Στα πλαίσια της μελέτης δημιουργήθηκε ένα μοντέλο προσομοίωσης που αναπαριστά ένα δίκτυο χαμηλής τάσης TN-C-S με δύο πανομοιότυπους οικιακούς καταναλωτές, όσον αφορά τη δομή της εσωτερικής ηλεκτρικής εγκατάστασής τους παρουσία ή μη διατάξεων αντικεραυνικής προστασίας. Σκοπός της προκειμένης μελέτης είναι να δειχθεί η βέλτιστη συνδεσμολογία των διατάξεων προστασίας μέσα σε εσωτερικές ηλεκτρικές εγκαταστάσεις έτσι ώστε να αποτρέπεται η ανάπτυξη επικίνδυνων τάσεων και ρευμάτων για τον άνθρωπο και τον εξοπλισμό της οικιακής εγκατάστασης. / The subject of this project is a study upon the dynamic performance of surge arresters as a part of the internal lightning protection system for a residential electrical installation. At first, a reference about the actions or the natural phenomena that cause surge overvoltages in low voltage systems is given in detail and is followed by an essential theoretical approach on the lighning phenomenon. Both the causes, the consequences and the conditions in which a lightning occurs are being analysed. Furthermore, the characteristics and the qualifications a Lightning Protection System needs to comply with, are given, according to the Greek Standard ΕΛΟΤ-1197 and the European Standards IEC 62305-2, IEC 61643-12. Along with writing this essay, a simulation model using Simulink-Matlab was produced. The model represents a LV TN-C-S system that distributes power to two households with identical internal electrical installation. The aim of the present study is to indicate the optimal connection of the surge protective devices (SPDs) in the domestic electrical installation in order to prevent the appearance of potentially dangerous overvoltages to the humans or to the household equipment.
4

[en] GROUND VEHICLES SUSPENSION AND STEERING MECHANISMS MODELING AND INTEGRATION THROUGH POWER FLOW / [pt] MODELAGEM E INTEGRAÇÃO DOS MECANISMOS DE SUSPENSÃO E DIREÇÃO DE VEÍCULOS TERRESTRES ATRAVÉS DO FLUXO DE POTÊNCIA

RICARDO TEIXEIRA DA COSTA NETO 27 October 2008 (has links)
[pt] A sub-divisão de um veículo em módulos é muito útil quando se quer estudar o comportamento dinâmico de um determinado subsistema e sua influência nos demais componentes. Em alguns casos, devido ao tipo de tratamento empregado para descrever os elementos, não se consegue perceber de que modo as variáveis inerentes a um subsistema interagem com as demais, e, por conseguinte, os subsistemas entre si. A abordagem modular baseada no fluxo de potência permite uma melhor identificação das relações de causa e efeito entre subsistemas, uma vez que se pode definir, de forma clara e consistente, quem são as variáveis de entrada e de saída de cada componente ou módulo, e, conseqüentemente, seus acoplamentos. Neste tipo de tratamento, aplicado aos sistemas mecânicos, uma vez estabelecida a cinemática de um subsistema, podese obter as relações entre os esforços que seus componentes produzem uns sobre os outros, a partir da caracterização da potência transmitida através dos seus diversos elementos. Este trabalho apresenta um procedimento semi-analítico de equacionamento modular aplicado à modelagem e integração dos sistemas de suspensão e direção de veículos terrestres, no qual as variáveis de entrada e saída indicam o fluxo de potência entre os elementos de todo o sistema. Tal abordagem tem como base a técnica dos Grafos de Ligação, empregada em sistemas multidomínio em geral, e usa alguns conceitos da metodologia dos Transformadores Cinemáticos, normalmente aplicada aos sistemas multicorpos. A partir da definição da geometria dos mecanismos em questão, encontram-se as matrizes que representam os vínculos cinemáticos entre seus elementos, das quais o funcionamento dos sistemas integrados pode ser simulado e analisado, e informações necessárias aos seus projetos determinadas. As equações (malhas) algébricas que existem em mecanismos com estrutura cinemática fechada são analiticamente resolvidas, evitando deste modo modelos matemáticos com equações diferenciais e algébricas simultâneas. Das relações cinemáticas, o modelo dinâmico (matrizes de inércia, rigidez e amortecimento, etc) é obtido, e novamente informações essenciais à análise e síntese dos sistemas podem ser determinadas. O comportamento no tempo desses modelos pode ser encontrado por um método de integração de equações diferenciais qualquer. Adota-se o Simulink/MatLab® para representar o modelo assim desenvolvido em diagrama de blocos, e conseqüentemente simulá-lo. Através deste tratamento, cada bloco da implementaçao em Simulink/MatLab® contém o correspondente modelo analítico de um único módulo, cujo estabelecimento depende das características dinâmicas do sistema que se deseja analisar. A vantagem de adotar tal representação, baseada no fluxo de potência, consiste no fato de que um módulo pode ser substituído por outro, descritivo de um elemento ou subsistema com a mesma função, porém com configuração física distinta, e, conseqüentemente, modelo matemático específico, sem qualquer alteração nos demais componentes do sistema. Este procedimento está sendo adotado para modelagem dos diversos sistemas veiculares, como os de suspensão, direção, transmissão e freios, e também os pneus, inseridos em um chassi, incluindo os graus de liberdade desejados do veículo, todos descritos de forma modular semi- analítica através da mesma abordagem, empregando a técnica de modelagem mais apropriada para representá-los. / [en] The sub-division of a vehicle in modules is very useful when we want to study the dynamical behavior of a certain sub-system and its influence in other components. In some cases, due to the type of treatment employed to describe the dynamic behavior of the elements, we don`t get to notice the way that inherent variables in a sub-system interacts with the others, and, consequently, the subsystems amongst themselves. The modular approach based on the power flow allows a better identification of the causal relationships among sub-systems, once it can define, in clear and consistent way, what are the input and output variables of each component or module, and, consequently, their couplings. In this type of treatment applied to the mechanical systems, once established the kinematics of a sub-system, it can be obtained the relationships among the efforts that their components produce on the other ones, from the characterization of the power transmitted through their several elements. This paper presents a semi-analytical procedure of modular modeling applied to the suspension and steering systems of a ground vehicle, in which the input and output variables indicate the power flow among the elements of the whole system. Such approach has as base the Bond Graphs technique, used in multidomain systems in general, and uses some concepts of the Kinematic Transformers methodology, usually applied to the multibody systems. From the mechanisms geometry, the matrices that represent the kinematics links between its elements are found, the operation of the integrated systems can be simulated and analyzed, and information about its design can be obtained. The algebraic loops (equations) inherent to mechanisms with closed kinematic structure are solved analytically, and there is not a mathematical model with simultaneous algebraic and differential equations. From the kinematic relations, the dynamic model (inertial, stiffness and damping matrices) is obtained, and again essential information to the systems analysis and synthesis can be determined. The models time behavior can be found by any differential equations integration method. The Simulink/Matlab is adopted to represent the model developed by block diagrams, and consequently to simulate it. Through this treatment, each block in the Simulink/Matlab implementation contains the correspondent analytical model of a single module, whose establishment depends on the dynamic characteristics of the system to be analyzed. The advantage of adopting such representation, based on the power flow, consists in the fact that a module can be substituted for other, descriptive of an element or sub-system with the same function, however with different physical configuration, and, consequently, specific mathematical model, without any alteration in the other components of the system. This procedure is being adopted for modeling all vehicular systems, like the suspension, steering, transmission and brakes systems, and also the tires, inserted in the chassis, including the desired degrees of freedom of the vehicle, all described in a semi- analytical modular way by the same approach, using the most appropriate modeling technique to represent them.
5

Identifikace parametrů asynchronního motoru / Identification of AC induction motor parameters

Křížek, Tomáš January 2008 (has links)
This thesis describes and realizes (in program Matlab/Simulink and in the microcontroller Freescale 56F8346) one off-line identification method of AC Induction motor parameters which are necessary to implement the field-oriented control strategy. The identification metod identify leakage inductance, magnetizing inductance and secondary time constants. The presented method is evaluted, advantages and disadvantages of this method are evaluated with reference to their possible use in real-machine. The experimental results and schemes which are presented demonstrate the feasibility methods. The thesis is dividend in seven chapters. Second chapter describes the basic principle and model AC induction motor. Third chapter generally describes identification methods. Fourth, fifth and sixth chapters deal with method which is based on a previous work of the authors [4] and [5].
6

Algoritmy pro systémy s technikou adaptivního frekvenčního skákání / Algorithms for adaptive frequency hopping spread spectrum systems

Zunt, Tomáš January 2009 (has links)
This master's thesis deal the system, which use the Frequency Hopping (FH). Is explained principle those techniques and her benefits and disadvantages. Follows description techniques Adaptive Frequency Hopping (AFH) that used the Bluetooth. Follows description other method for setup hopset such as Dynamic Frequency Hopping (DFH), which used standards 802.22. 22. Is an emerging standard for Wireless Regional Area Networks (WRAN) operating on a license-exempt and non-interference basis in the spectrum allocated to TV broadcast services (between 47–910 MHz). Other method introduces the Adaptive Frequency Rolling (AFR), a particular instance of frequency hopping (FH) that enables the collocated WPANs to cooperate and avoid the self-interference. The AFR uses as input solely the observed packet error rate (PER) and it does not require any exchange of information among the collocated WPANs. The effect of the FR over a longer time interval is that the WPANs use the complete set of disposable channels in an implicit time-division and cooperative manner. Last method described in this Thesis is Dynamic Adaptive Frequency Hopping (DAFH). The basic strategy applied in DAFH is a binary search for a hopset that offers smaller PER. The set of admissible hopsets depends on the total number of available channels and the maximal level of binary divisions. Practical part of the master's thesis describes proposal model AFH, with usage of Matlab Simulink programme. In thesis are described function each blocks a their setting. Simulation parameters can change in simple graphic interface. The model is able to simulate influence of static and dynamic interference in transmission band of two communicating devices.

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