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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.
21

CONTROLE DE CORRENTE APLICADO EM INVERSOR MONOFÁSICO DE TENSÃO / CURRENT CONTROL APPLIED IN SINGLE-PHASE VOLTAGE INVERTERS

Lima, Marcel Soares 20 February 2015 (has links)
Made available in DSpace on 2016-08-17T14:52:39Z (GMT). No. of bitstreams: 1 DISSERTACAO_MARCEL SOARES LIMA.pdf: 17818100 bytes, checksum: 95b36384b873fd5da81040a537b53ec1 (MD5) Previous issue date: 2015-02-20 / With advancement of power electronics and the wide range of applications involving single-phase inverter voltage, current controllers has gained great prominence, because they control the flow of energy supplied to the grid or to a load and compensate some quality energy problems. For this, various techniques for controlling power has been studied in order to meet the robustness characteristics, accuracy and speed of response. In addition, another important characteristic, which has been adopted for accurately determining the choice of the current driver is the possibility of eliminating disturbances in specific frequency, such as those caused by harmonicas of the fundamental signal. This paper presents the study, analysis and resonant controller design. Since this controller is equivalent to adding two PI controllers synchronously, a positive sequence and negative sequence other, implemented in the stationary frame of reference, we will investigate the possible resonance structures of controlling synchronous equivalent to PI controllers, and vector classic and the advantages and disadvantages of each. The analyses of resonant controllers are held in the continuous domain and then the drivers are implemented in discrete domain, taking into account the computational delay. It is also performed the analysis and design of strategies for controlling resonant with and without a delay compensator. Finally, experimental tests will be performed to confirm the analyzes in this paper. / Com o avanço da eletrônica de potência e a vasta gama de aplicações que envolvem os inversores monofásicos de tensão, os controladores de corrente têm ganhado grande destaque, pois controlam o fluxo de energia fornecida à rede elétrica ou a uma carga e compensam alguns problemas de qualidade de energia. Para isso, diversas técnicas de controladores de corrente têm sido estudadas com o intuito de atender as características de robustez, precisão e rapidez na resposta. Além disso, outra característica importante, e que tem sido rigorosamente adotada para determinar a escolha dos controladores de corrente, é a possibilidade de eliminar distúrbios em frequências específicas, como por exemplo, aqueles causados por harmônicas do sinal fundamental. Esta dissertação apresenta o estudo, análise e projeto do controlador ressonante. Uma vez que este controlador é equivalente à adição de dois controladores PI síncronos, um de sequência positiva e outro de sequência negativa, implementados no referencial estacionário, serão investigados as possíveis estruturas dos controladores ressonantes equivalentes aos controladores PI síncronos, clássico e vetorial, bem como as vantagens e desvantagens de cada um. As análises dos controladores ressonantes são realizadas no dominio contínuo e, posteriormente, os controladores são implementados no dominio discreto, levando em consideração o atraso computacional. Também é realizada a análise e projeto das estratégias de controladores ressonantes com e sem um compensador de atraso. Por fim, serão realizados ensaios experimentais para confirmar as análises realizadas no decorrer deste trabalho.
22

Odporová pila / Resistance saw

Kalčík, Petr January 2009 (has links)
This work is focused on the design and construction of component parts of resistance saw. Mechanical parts consist of a movable bracket and a taut cutting wire of Constantan. Electrical parts are designed to supply and control temperature of the cutting wire. The current intensity in the cutting wire is compared with the required current intensity. The difference of these two measurements is fed into a PI - controller. The next part is a PWM generator which generates the square wave signal. The pulse ratio of this signal is proportional to the required temperature of the cutting wire. This signal switches a switching converter that consists of a power transistor P-MOSFET IRF5210 and a diode MBR20100CT. Choking coil with a ferrite E core and with the cutting wire is connected to the output of the converter.
23

Investigation of active anti-roll bars and development of control algorithm

Agrawal, Harshit, Gustafsson, Jacob January 2017 (has links)
Active anti-roll bars have recently found greater acceptance among premium car manufacturers and optimal application of this technology has emerged as an important field of research. This thesis investigates the potential of implementing active anti-roll bars in a passenger vehicle with the purpose of increasing customer value. For active anti-roll bars, customer value is defined in terms of vehicle’s ride comfort and handling performance. The objective with this thesis is to demonstrate this value through development of a control algorithm that can reflect the potential improvement in ride comfort and handling. A vehicle with passive anti-roll bars is simulated for different manoeuvres to identify the potential and establish a reference for the development of a control algorithm and for the performance of active anti-roll bars. While ride is evaluated using single-sided cosine wave and single-sided ramps, handling is evaluated using standardized constant radius, frequency response and sine with dwell manoeuvres.The control strategy developed implements a combination of sliding mode control, feed forward and PI-controllers. Simulations with active anti-roll bars showed significant improvement in ride and handling performance in comparison to passive anti-roll bars. In ride comfort, the biggest benefit was seen in the ability to increase roll damping and isolating low frequency road excitations. For handling, most significant benefits are through the system’s ability of changing the understeer behaviour of the vehicle and improving the handling stability in transient manoeuvres. Improvement in the roll reduction capability during steady state cornering is also substantial. In conclusion, active anti-roll bars are undoubtedly capable of improving both ride comfort and handling performance of a vehicle. Although the trade-off between ride and handling performance is significantly less, balance in requirements is critical to utilise the full potential of active anti-roll bars. With a more comprehensive control strategy, they also enable the vehicle to exhibit different driving characteristics without the need for changing any additional hardware.
24

Simulation And Performance Evaluation Of A Fast And High Power Pulsed Laser Diode Driver For Laser Range Finder

Altinok, Yahya Kemal 01 June 2012 (has links) (PDF)
Laser Diodes (LDs) are semiconductor coherent lightening devices which are widely used in many fields such as defence, industry, medical and optical communications. They have advantageous characteristics such as having higher electrical-to-optical and optical-to-optical conversion efficiencies from pump source to useful output power when compared to flash lamps, which makes them the best devices to be used in range finding applications. Optical output power of lasers depends on current through LDs. Therefore, there is a relationship between operating life and work performance of LDs and performance of drive power supply. Even, weak drive current, small fluctuations of drive current can result in much greater fluctuations of optical output power and device parameters which will reduce reliability of LDs. In this thesis, a hardware for a fast and high power pulsed LD driver is designed for laser range finder and is based on linear current source topology. The driver is capable of providing pulses up to 120A with 250&mu / s pulse width and frequencies ranging from 20Hz to 40Hz. It provides current pulses for two LD arrays controlled with a proportional-integral (PI) controller and protect LDs against overcurrents and overvoltages. The proposed current control in the thesis reduces current regulation to less than 1% and diminishes overshoots and undershoots to a value less than 1% of steady-state value, which improves safe operation of LDs. Moreover, protection functions proposed in the thesis are able to detect any failure in driver and interrupt LD firing immediately, which guarantees safe operation of LDs.
25

Análise, projeto e implementação de conversores CC-CC com ampla faixa de conversão aplicados em iluminação de estado sólido

Britto, Jonas Reginaldo de 18 December 2009 (has links)
This work consists of the study, design and implementation of DC-DC converters, used in lighting systems based on light emitting diodes (LEDs). Can be powered by an universal AC voltage source or battery, and the current in the LEDs is controlled digitally. The main objective is to present a proposal of new step-up/down converters topologies with full conversion much higher than that of conventional converters. So, is initially presented an overview of solid-state lighting (SSL). Following is presented the study on the dynamic behavior of converters based on modeling by the method of varying state-space average, ending with the design of a digital PI controller. This work resulted in the application for a patent PI-0801425-6 filed with the INPI, which presents a new family of converters with full conversion extremely wide, called cubic converters. / O presente trabalho consiste do estudo, projeto e implementação de conversores CCCC, aplicados em sistemas de iluminação de estado sólido baseado em diodos emissores de luz (LEDs). Podem ser alimentados por uma fonte de tensão alternada universal ou por uma bateria sendo que a corrente nos LEDs é controlada digitalmente. O objetivo principal é apresentar uma proposta de novas topologias de conversores abaixadores/elevadores com faixa de conversão muito maior que a dos conversores convencionais. Portanto, inicialmente é apresentada uma visão geral sobre iluminação de estado sólido (SSL). Na sequência, é apresentado o estudo sobre o comportamento dinâmico dos conversores baseado na modelagem através do método de variáveis de espaço de estados médio, finalizando com o dimensionamento de um controlador PI digital. Este trabalho resultou no pedido de patente de invenção PI-0801425-6 depositado junto ao INPI, o qual apresenta uma nova família de conversores com faixa de conversão extremamente larga, denominados de conversores cúbicos. / Doutor em Ciências
26

Estudo de técnicas de controle de máquinas de relutância chaveada para aplicações em sistemas de acionamentos com velocidade variável

Almeida, Lucas Alves de 27 February 2018 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-05-25T12:16:21Z No. of bitstreams: 1 lucasalvesdealmeida.pdf: 7514122 bytes, checksum: a0029ec07180541f754e98112ec47b6b (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-06-14T11:52:17Z (GMT) No. of bitstreams: 1 lucasalvesdealmeida.pdf: 7514122 bytes, checksum: a0029ec07180541f754e98112ec47b6b (MD5) / Made available in DSpace on 2018-06-14T11:52:17Z (GMT). No. of bitstreams: 1 lucasalvesdealmeida.pdf: 7514122 bytes, checksum: a0029ec07180541f754e98112ec47b6b (MD5) Previous issue date: 2018-02-27 / Sistemas eletromecânicos são de grande importância atualmente, e a procura por maior eficiência e desempenho aliados a um menor custo justificam a busca por alternativas tanto em topologia quanto no controle e acionamento de tais sistemas. A máquina de relutância chaveada é capaz de cumprir estes requisitos e tem despertado o interesse de pesquisadores e empresas nos últimos anos, emergindo como uma alternativa viável em diversas aplicações. Porém, esta máquina possui características singulares. Por conta de sua estrutura duplamente saliente, seu funcionamento correto depende da aplicação de pulsos de corrente por determinados intervalos de tempo, e na sequência correta, seus parâmetros são variáveis no tempo, apresentando um comportamento com características não-lineares. Tais particularidades fazem com que seja difícil controlar o torque destas máquinas, as quais possuem a tendência de apresentar altas oscilações durante a mudança da excitação de cada fase. Este trabalho tem por objetivo contribuir com o estudo da modelagem e do acionamento de uma máquina de relutância chaveada. É apresentada sua modelagem matemática e um modelo de simulação que leva em consideração as não linearidades existentes. Em seguida são apresentadas técnicas de controle de corrente que incluem um regulador de histerese, um controlador PI e um controlador por modos deslizantes. Também é utilizado um método capaz de determinar o momento em que cada fase deve ser acionada, baseado no ângulo do rotor, e uma técnica de variação dos ângulos de acionamento de maneira dinâmica, usados em conjunto com os controladores propostos. O trabalho também caracteriza e apresenta as funções de divisão de torque como uma maneira de reduzir drasticamente as oscilações de torque. São apresentadas as operações como motor e como gerador, bem como um exemplo de aplicação de modo a ilustrar ambos os modos de operação. / Electromechanical systems have a huge relevance nowadays, and seeking for improvements in efficiency and performance at the lowest cost make valid to identify topological and control alternatives of these systems. The switched reluctance machine is capable to fulfill such requirements and emerges as an interesting field of research. Academics and industrial works shows that it is a promising alternative in several applications. However, this machine presents unique characteristics, like the doubly salient structure, the necessity to apply phase currents in a sequence determined by the stator/rotor pole ratio, its time variantparameters,andthestrongnonlinearcharacteristics. Suchsingularitiesmaketorque control hard, as it tends to present high ripples and makes a lot of noise. This thesis aims to contribute on switched reluctance machine modeling and drive system. A mathematical model is presented, and also a simulation model that accounts for nonlinearities, making possible to simulate the machine accurately in a computational environment. A hysteresis regulator, a PI controller and a sliding mode controller are designed and simulated. An algorithm to determine when each phase should be excited based on rotor angle is used, and a technique to change such firing angles dynamically is developed that can be used along with current control methods presented. The work also defines and presents torque sharing functions as a way to greatly reduce torque ripple. Motor and generator operation are contemplated, and both modes are illustrated in an application example.
27

Controle de potência do gerador de relutância variável de 12/8 utilizando o controlador fuzzy pi auto-ajustável

Ccantuta Chirapo, Karlos Alexander January 2018 (has links)
Orientador: Prof. Dr. José Luis Azcue Puma / Coorientador: Prof. Dr. José Alberto Torrico Altuna / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, Santo André, 2018. / Este trabalho apresenta o controle de potência do gerador de relutância variável de 12/8 utilizando o controlador Fuzzy PI auto-ajustável e o controlador P+ressonante para o conversor conectado à rede elétrica. Inicialmente são estudados os princípios de operação da máquina e a topologia do conversor eletrônico de potência. Usando o software de simulação Matlab/Simulink é implementado o modelo da máquina de relutância variável utilizando as curvas características de corrente e de torque. Com o objetivo de controlar a potência gerada pela máquina e utilizando seu modelo matemático dinâmico projeta-se o controlador PI, e implementa-se o controlador Fuzzy PI auto-ajustável para atingir o mesmo objetivo. Assim, projeta-se também um controlador PI para o controle da tensão CC além de um controlador P+ressonante com o objetivo de melhorar a resposta em regime permanente da potência injetada na rede elétrica. Para este propósito é utilizado um conversor monofásico de dois níveis. Os resultados das simulações mostram o bom desempenho do sistema proposto e o controlador de potência é validado também através de resultados experimentais. / This work presents the power control of the 12/8 variable reluctance generator using Fuzzy self-tuning PI controller and the P+resonant controller for the converter connected to the electric network. Initially are studied the principles of operation of the machine and power electronic converter topology. Using the Matlab/Simulink simulation software is implemented the model of switched reluctance machine using the current and its torque characteristic curves. With the purpose of controlling the power generated by the machine and using his dynamic mathematical model is designed the PI controller, and the Fuzzy self-tuning PI controller is implemented to achieve the same objective. So, also is designed a PI controller for control of the link DC, in addition to the P+resonant controller with the objective of improving the response to its steady state of the injected power into the electric network. For this purpose it is used a single-phase two-level converter. The results of the simulations show the good performance of the proposed system and the power controller is validated by experimental results.
28

Adaptivní řízení pohonu se stejnosměrným motorem / Adaptive Control of a DC Drive

Krkoška, Roman January 2008 (has links)
The master’s thesis deals with method of adaptive control of electrical drives. It aims at control of DC motor with using self tunning controller (STC) and gain-schedulink in simulative enviroment of MATLAB. The first part of the thesis deals with of basic methods adaptive control of electrical drives and with of basic identification methods, computation of controller parameters and control laws of controllers. The second part of the thesis is aimed at applying adaptive controllers to mathematical model of controlled system. Include monitoring parameters of identification The thesis contains originate programs include source files.
29

Modelling and Control of a Dual Sided Linear Induction Motor for a scaled Hyperloop Pod / Modellering och styrning av en dubbelsidig linjär induktionsmotor för en skalenlig Hyperloop-pod

Anand, Vivek January 2020 (has links)
The electrification era has been marked up by an increase in volume of electric vehicles which are directly or indirectly powered by electricity. Railways, roadways and airways are being electrified as we speak at their own respective rate. In addition to that upcoming concepts for transport solution such as hyperloop also described as the fifth mode of transportation will be electrified. The current thesis work is based on developing the model and control of the propulsion system of a scaled Hyperloop pod designed by student team KTH Hyperloop representing KTH. The team competes in Hyperloop competition organized by Spacex and the goal is to achieve the highest possible speed in a given distance and track designed by SpaceX. In order to achieve the goal of being the fastest, the scaled pod uses a Double Sided Linear Induction Motor (DSLIM) as mentioned in the subsequent chapter. The motor modelling is done on Simulink and is similar to a rotary induction motor (RIM). However the presence of end effect in DSLIM makes it different from RIM and has been discussed subsequently. The control strategy uses a synchronous frame PI control for the current control and sensor based speed control for controlling the speed of the pod.The speed control output is a reference current which is used as an input to the current controller which finally gives voltage as the control output. The corresponding bandwidth for the various loops have been calculated based on motor parameters as discussed in the method section. The validation of the motor model and the corresponding controller has been discussed in the result section, where the accuracy of the controller for the designed modelled is discussed. / Elektrifieringstiden har präglats av en ökning i volym av elfordon som direkt eller indirekt drivs med el. Järnvägar, vägar och luftvägar elektrifieras just nu med deras respektive takt. Utöver det kommer kommande koncept för transportlösning som hyperloop som också beskrivs som det femte transportsättet att elektrifieras. Detta examensarbete bygger på att utveckla modellen och regleringen av framdrivningssystemet för en nedskalad Hyperloop-pod utvecklad av studentteamet KTH Hyperloop som representerar KTH. Teamet tävlar i Hyperloop-tävlingen organiserad av SpaceX och målet är att uppnå högsta möjliga hastighet på ett visst avstånd och spår framtaget av SpaceX. För att uppnå målet om att vara snabbast använder den nedskalade podden en dubbelsidig elektrisk linjär induktionsmotor (DSLIM) som nämns i det följande kapitlet. Den elektriska motormodelleringen görs i Simulink och liknar en roterande induktionsmotor(RIM). Men närvaron av ’end effect’ i DSLIM gör den annorlunda än RIM och har diskuterats därefter. Styrstrategin använder en synkron ram-PI-styrning för strömstyrning och sensorbaserad hastighetsreglering för att styra hastigheten på podden. Varvtalsstyrningsutgången är en referensström som används som en ingång till den nuvarande styrenheten som slutligen ger spänning som slutling styrning. Motsvarande bandbredd för de olika slingorna har beräknats baserat på elektriska motorparametrar som diskuterats i metodavsnittet.Valideringen av elmotormodellen och motsvarande styrenhet har diskuterats i resultatsektionen, där noggrannheten hos styrenheten för den konstruerade modellerna diskuteras.

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