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 &amp / #8710 / /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 Kemerk&ouml / 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.

This dissertation is aimed at examining signal integrity degradation factors and realizing signal integrity enhancement circuits for both wired and wireless communication systems. For wired communication systems, an optical coherent system employing an electrical equalization circuit is studied as a way of extending the transmission distance limited by optical fiber dispersion mechanisms. System simulation of the optical coherent receiver combined with the feed-forward equalizers is performed to determine the design specification of the equalizer circuit. The equalization circuit is designed and implemented in a 0.18 µm complementary metal-oxide semiconductor (CMOS) process and demonstrates the capability to extend the transmission reach of long-haul optical systems over single-mode fiber to 600 km. Additionally, for wireless applications, signal integrity issues found in a full-duplex wireless communication network are examined. Full-duplex wireless systems are subject to interference from their own transmitter leakage signals; thus, a transmitter leakage cancellation circuit is designed and implemented in a 0.18 µm CMOS technology. The proposed cancellation circuit is integrated with a low-noise amplifier and demonstrates over 20 dB of transmitter leakage signal suppression.

The focus of this research is on deriving small signal stability models for different Flexible AC Transmission Systems devices by introducing a simple systematic method that is applicable to any dynamic device. Two different small signal models for Unified Power Flow Controllers are introduced. One model is called the power control mode and the other model is the voltage control mode. The two models are compared from transient stability point of view to show the necessity of developing both models for UPFC. The thesis also shows how to derive the small signal stability model of Static Synchronous Compensator, as the shunt branch of UPFC. The small signal stability models of both devices are then validated to ensure the accuracy of the derived models. STATCOM and UPFC power control mode are validated against PSCAD. The UPFC voltage control mode is validated against nonlinear solution of system equations.

The thesis deals with the optimal pose selection for geometric and elastostatic calibration for industrial robots employed in machining of large parts. Particular attention is paid to the improvement of robot positioning accuracy after compensation of the geometric and elastostatic errors. To meet the industrial requirements of machining operations, a new approach for calibration experiments design for serial and quasi-serial industrial robots is proposed. This approach is based on a new industry-oriented performance measure that evaluates the quality of calibration experiment plan via the manipulator positioning accuracy after error compensation, and takes into account the particularities of prescribed manufacturing task by introducing manipulator test-poses. Contrary to previous works, the developed approach employs an enhanced partial pose measurement method, which uses only direct position measurements from an external device and allows us to avoid the non-homogeneity of relevant identification equations. In order to consider the impact of gravity compensator that creates closed-loop chains, the conventional stiffness model is extended by including in it some configuration dependent elastostatic parameters, which are assumed to be constant for strictly serial robots. Corresponding methodology for calibration of the gravity compensator models is also proposed. The advantages of the developed calibration techniques are validated via experimental study, which deals with geometric and elastostatic calibration of a KUKA KR-270 industrial robot.

The focus of this research is on deriving small signal stability models for different Flexible AC Transmission Systems devices by introducing a simple systematic method that is applicable to any dynamic device. Two different small signal models for Unified Power Flow Controllers are introduced. One model is called the power control mode and the other model is the voltage control mode. The two models are compared from transient stability point of view to show the necessity of developing both models for UPFC. The thesis also shows how to derive the small signal stability model of Static Synchronous Compensator, as the shunt branch of UPFC. The small signal stability models of both devices are then validated to ensure the accuracy of the derived models. STATCOM and UPFC power control mode are validated against PSCAD. The UPFC voltage control mode is validated against nonlinear solution of system equations.

Made available in DSpace on 2014-06-11T19:30:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-21Bitstream added on 2014-06-13T19:19:29Z : No. of bitstreams: 1 pereira_als_dr_ilha.pdf: 1505539 bytes, checksum: 8b3fa09211b5f80a63a93c6fd21675aa (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho apresenta estudos referentes à inclusão do dispositivo FACTS STATCOM e a utilização de Redes Neurais Artificiais para o ajuste dos parâmetros de sinais adicionais estabilizantes (PSS’s e POD’s) no sistema de potência multimáquinas. O objetivo é a melhoria da estabilidade frente às pequenas perturbações do sistema de energia elétrica. O modelo matemático utilizado para o estudo das oscilações eletromecânicas de baixa freqüência em sistemas de energia elétrica foi o Modelo de Sensibilidade de Potência (MSP), modificado para permitir a inclusão do dispositivo STATCOM. Este modelo baseia-se no princípio de que o balanço de potência ativa e reativa deve ser satisfeito continuamente em qualquer barra do sistema durante um processo dinâmico. Prosseguindo na realização do trabalho foram desenvolvidos os modelos matemáticos para a inclusão dos PSS’s e POD’s no sistema elétrico, bem como foi realizada uma discussão a respeito da escolha do local de instalação destes controladores e técnicas clássicas para o ajuste de seus parâmetros. A partir disto foram utilizadas redes neurais artificiais (RNA’s) com o objetivo de ajustar os parâmetros dos controladores. A rede utilizada para este fim foi a do tipo Perceptron Multicamadas, sendo utilizado para o seu treinamento o algoritmo Backpropagation. Simulações foram realizadas e os resultados obtidos para os sistemas testes Sul Brasileiro, Simétrico de Duas Áreas e New England são comentados / This work presents studies about the inclusion of FACTS STATCOM devices using neural networks tune stability additional signal parameters (PSS’s and POD’s) on a multi-machine power system. The objective is to improve the stability to small perturbations in electric power systems. The mathematical model used for studying the lower frequency electromechanical oscillations is the Power Sensitivity Model (PSM), modified to allow the inclusion of the STATCOM device. This model is based on the principle that the active and reactive power balance must be continuously satisfied in every bus of the system during the dynamical process. Mathematical models were developed to include the PSS’s and POD’s on the electrical system, as well as the local to install these control devices and the classical techniques to adjust these parameters. Afterwards, the neural networks were used to adjust the parameters of the controllers. The neural network used is a Perceptron Multi Layer, with the training by backpropagation. Simulations were effectuated for the South Brazilian Power System, the Two Areas Symmetrical Power System and the New England Power System

Made available in DSpace on 2016-12-12T20:27:38Z (GMT). No. of bitstreams: 1 Rubens Hock.pdf: 9150198 bytes, checksum: dc75d13b884c75e842633257c0db27e6 (MD5) Previous issue date: 2015-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This paper presents a mobile voltage regulator based in a Distribution Static Synchronous Compensator (DSTATCOM) applied to low voltage distribution grids. The DSTATCOM consists in a three-phase four-wire inverter connected to the grid through a second order low pass filter. The control structure is composed of three output voltage loops with active damping and the two dc bus loops. In addition, a new concept of Minimum Power Point Tracking (mPPT) is introduced, forcing the DSTATCOM to operate with the minimum power. In certain conditions, this means no compensation. The dynamic models of the converter are presented, as well as the control design. Simulation results show the capacity of voltage regulation and the features of the mPPT, even under grid and load unbalances and nonlinear loads. This work is concluded with the construction of a 30 kVA prototype and validation through experimental results proves the proper functioning of the voltage regulator. / Esse trabalho apresenta um regulador de tensão móvel baseado em um compensador estático de reativos (DSTATCOM) aplicado a redes de distribuição de baixa tensão. O DSTATCOM consiste em um inversor trifásico a quatro fios conectado à rede através de um filtro de segunda ordem. A estrutura de controle é composta por três malhas de tensão de saída com amortecimento ativo e duas malhas de tensão do barramento cc. Em adição, um novo conceito de rastreamento da mínima potência (mPPT) é introduzido, forçando o DSTATCOM a operar com a mínima potência. Em certas ocasiões, isso significa nenhuma compensação. Os modelos dinâmicos do conversor são apresentados, assim como o projeto de controle. Resultados de simulação mostram a capacidade de regulação da tensão e as características do mPPT, mesmo com desequilíbrios na rede e/ou na carga e com cargas não lineares. O trabalho é concluído com a construção de um protótipo de 30 kVA e validação dos estudos através de resultados experimentais obtidos comprovam o bom funcionamento do regulador de tensão.

Orientador: Prof. Dr. Edmarcio Antonio Belati / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2017. / Neste trabalho analisou-se o desempenho de um Sistema Elétrico de Potência, quando alocados TCSC (do inglês, Thyristor Controlled Serie Compensator), e determinaram-se seus parâmetros ótimos de controle buscando maximizar a capacidade de transmissão total do sistema e melhorar o seu perfil de tensão, operando com suas variáveis dentro de limites pré-estabelecidos. Para tanto, foram modeladas variações do problema de Fluxo de Potência Ótimo Reativo (FPOR) e executadas em duas fases, identificadas como fase de alocação e fase de análise. Na fase de alocação foram realizadas simulações para analisar a alocação de diferentes quantidades de TCSC no sistema, com o objetivo de maximizar a capacidade de transmissão total e, por conseguinte, com base em um carregamento previsto na rede, foi determinada a quantidade mínima de dispositivos necessários para atender tal demanda. Em seguida, com o número de TCSC definido, os mesmos foram realocados com o objetivo de minimizar o desvio de tensão. Na fase de análise, os TCSC alocados na fase anterior foram mantidos com objetivo de otimizar o perfil de tensão, simulando variações nas cargas do sistema. Na fase de alocação, foi utilizada uma modelagem de Programação Não Linear Inteira Mista (PNLIM). Na fase de análise, o perfil de tensão foi otimizado por meio de uma modelagem de Programação Não Linear (PNL). Os resultados obtidos para os sistemas testes IEEE-14 e -118 barras demonstram os benefícios da utilização de TCSC na rede, pois possibilitou o aumento da carga total do sistema, e proporcionou uma melhora no perfil de tensão por meio do seu ajuste ótimo. / This work analyzed the electric power system performance when allocated TCSC (Thysristor Controlled Series Compensator) and determined their optimal control parameters in order to maximize the total transmission capability of the system and improve the voltage profile, operating within their pre-stablished limits. For this purpose, variations of Reactive Optimal Power Flow (FPOR) problems were modeled and executed in two phases, identified as phase of allocation and phase of analysis: In the allocation phase, simulations were performed to analyze the allocation of different amounts of TCSC in the system in order to maximize the total transmission capacity and, therefore, based on a predicted loading in the network, the minimum amount of devices was determined to attain such demand. Then, as the number of TCSC was defined, they were reallocated with the objective of minimizing the voltage deviation. In the analysis phase, the TCSC were maintained by considering the objective of optimizing the voltage profile and simulating loads variations of the system. In the allocation phase, a Mixed Integer Nonlinear Programming (MINLP) model was used. In the analysis phase, the voltage profile was optimized through a Nonlinear Programming (NLP) modeling. The results for the IEEE-14 and -118 test systems demonstrated the benefits of using the TCSC in the network because it allowed the increase of the total load of the system and provided an improvement in the voltage profile through its optimum adjustment.

In this master thesis, the development of an electronic ballast with variable luminous flux for a T5 fluorescent lamp is presented. Several technics for the control of the power variation have already been discussed in the literature. Therefore, this work presents a method that blends two of the most traditional technics: the control done by altering the bus voltage and the control done through the changing of the switching frequency. To achieve this, the electronic circuit is composed by a power factor pre-regulator, which is a SEPIC converter with digitally controlled output voltage, a half-bridge inverter and a LCC resonant filter. For the pre-regulation stage, a proportional-integral compensator is used as the control method, which provides different levels of output voltage with an almost zero error when compared to the reference voltage and a satisfactory response to line disturbances. The half-bridge inverter control is done with the IR21592 IC, which keeps the phase angle fixed for the system’s entire operation band through a phase control loop. In order to validate the efficiency of this method, the electronic circuit is also evaluated when operating with the classical approach, by using a constant bus voltage and controlling the phase angle of the resonant filter to change the lamp’s luminous flux. Furthermore, the pre-heating of the lamp ’s filaments is analyzed and its temperatures are controlled by a Flyback converter, according to the power variation. / Essa dissertação apresenta o desenvolvimento de um pré-regulador de fator de potência aplicado a um reator eletrônico com variação de fluxo luminoso para uma lâmpada fluorescente modelo T5. Diversas técnicas para o controle da variação da potência em lâmpadas fluorescentes já foram discutidas na literatura, sendo que nesse trabalho será abordado um método que mescla duas das principais técnicas, que são: o controle feito pela variação da tensão de barramento e o controle feito através da variação da frequência de comutação do inversor ressonante. Para isso, o reator é composto de um estágio pré-regulador de fator de potência, formado por um conversor SEPIC com tensão de saída variável e controlada digitalmente, um inversor half-bridge e um filtro LCC ressonante. No estágio pré-regulador é utilizado um compensador proporcional integral para os diversos níveis de tensão de saída, o qual proporciona uma tensão de barramento com erro praticamente nulo em relação a referência e uma satisfatória resposta quando submetido a distúrbios da rede elétrica. O controle do inversor half-bridge é feito pelo CI IR21592, o qual, através de uma malha PLL, mantém o ângulo de fase da corrente do filtro ressonante fixo para toda faixa de operação do reator. Para a validação do desempenho do método proposto, é também avaliado o rendimento do circuito operando de forma clássica, utilizado uma tensão de barramento fixa e controlando o ângulo de fase da corrente do filtro ressonante para se obter a variação do fluxo luminoso da lâmpada. Também é avaliado o preaquecimento e o aquecimento dos filamentos da lâmpada durante a variação da potência, realizado por um conversor Flyback.

Submitted by Morgana Silva (morgana_linhares@yahoo.com.br) on 2016-07-27T16:18:26Z No. of bitstreams: 1 arquivototal.pdf: 1682868 bytes, checksum: e6813f2f2930d8867270563d26fb878c (MD5) / Made available in DSpace on 2016-07-27T16:18:26Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1682868 bytes, checksum: e6813f2f2930d8867270563d26fb878c (MD5) Previous issue date: 2016-02-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work proposes a repetitive-based control for series compensator with the objective of dynamically restore the voltage applied to sensitive and critical loads of power system. The control mitigates voltage sags while also minimize harmonic distortions. Its transfer function is simple to be realized and does not require any harmonic selective filters. The control system acts on sinusoid references and it is implemented in each phase independently. Another important aspect of the proposed system are the optimization strategies to minimize either the voltage injection or the active power injection. One of these strategies is to optimize the magnitude of the compensation voltage sag with the smallest voltage magnitude injection by the series compensator. For this purpose, the compensating voltage injected must be in phase with the voltage supply. Is possible to control the injection of the voltage compensation to minimize active power injection by the series compensator to compensate a voltage sag. To perform the voltage correction with minimum active power injection were developed analytical expressions for the magnitude and angle of the injected voltage. To implement theses strategies, an recursive least-squares algorithm is used to estimate the grid voltage. A laboratory-scale series compensator was developed to validate the method. Simulations and experimental results are presented and show the efficacy of the proposed method. / Este trabalho propõe um controle repetitivo para compensadores série com o objetivo de restaurar dinamicamente a tensão aplicada a cargas sensíveis e críticas de sistemas de energia. O controle pode mitigar afundamentos de tensão ao mesmo tempo que compensa distorções harmônicas. Sua função de transferência é simples de ser implementada e não requer qualquer filtro seletivo de harmônicos. O sistema de controle atua sobre as referências senoidais e deve ser implementado em cada fase independentemente. Um outro aspecto importante do trabalho são as estratégias de otimização para minimizar a tensão de compensação ou a potência ativa fornecida pelo compensador. Um destas estratégias é a otimização pela amplitude, em que a compensação do afundamento de tensão ocorre com a menor injeção de amplitude de tensão por parte do compensador série. Para isso, a tensão injetada pelo compensador deve estar em fase com a tensão da rede afundada. Pode-se, também, controlar a injeção da tensão de compensação para minimizar a potência ativa a ser injetada pelo compensador série para compensar um afundamento de tensão. Para realizar a correção com a mínima injeção de potência ativa utilizou-se expressões analíticas para obter a magnitude e o ângulo da tensão a ser injetada. Na implementação destas estratégias foi utilizado um algoritmo recursivo de mínimos quadrados para estimar a amplitude e fase da tensão da rede. Um sistema compensador série foi montado em laboratório para validar o método. As simulações e resultados experimentais são apresentados e constatam a eficácia do método proposto.