In this thesis the eigenstructure (eigenvalues and eigenvectors) assignment technique based algorithm has been developed for the design of controllers for power system applications. The application of the algorithm is demonstrated by designing power system stabilizers (PSSs) that are extensively used to address the small-signal rotor angle stability problems in power systems. In the eigenstructure assignment technique, the critical eigenvalues can be relocated as well as their associated eigenvectors can be modified. This method is superior and yield better dynamical performance compared to the widely used frequency domain design method, in which only the critical eigenvalues are relocated and no attempt is made to modify the eigenvectors. The reviewed published research has demonstrated successful application of the eigenstructure assignment technique in the design of controllers for small control systems. However, the application of this technique in the design of controllers for power systems has not been investigated rigorously. In contrast to a small system, a power system has a very large number state variables compared to the combined number of system inputs and outputs. Therefore, the eigenstructure assignment technique that has been successfully applied in the design of controllers for small systems could not be applied as is in the design of power system controllers. This thesis proposes a novel approach to the application of the eigenstructure assignment technique in the design of power system controllers. In this new approach, a multi-objective nonlinear optimization problem (MONLOP) is formulated by quantifying different design objectives as a function of free parametric vectors. Then the MONLOP is solved for the free parametric vectors using a nonlinear optimization technique. Finally, the solution of the controller parameters is obtained using the solved free parametric vectors. The superiority of the proposed method over the conventional frequency domain method is demonstrated by designing controllers for three different systems and validating the controllers through nonlinear transient simulations. One of the cases includes design of a PSS for the Manitoba Hydro system having about 29,000 states variables, which demonstrates the applicability of the proposed algorithm for a practical real-world system.

In this thesis the eigenstructure (eigenvalues and eigenvectors) assignment technique based algorithm has been developed for the design of controllers for power system applications. The application of the algorithm is demonstrated by designing power system stabilizers (PSSs) that are extensively used to address the small-signal rotor angle stability problems in power systems. In the eigenstructure assignment technique, the critical eigenvalues can be relocated as well as their associated eigenvectors can be modified. This method is superior and yield better dynamical performance compared to the widely used frequency domain design method, in which only the critical eigenvalues are relocated and no attempt is made to modify the eigenvectors. The reviewed published research has demonstrated successful application of the eigenstructure assignment technique in the design of controllers for small control systems. However, the application of this technique in the design of controllers for power systems has not been investigated rigorously. In contrast to a small system, a power system has a very large number state variables compared to the combined number of system inputs and outputs. Therefore, the eigenstructure assignment technique that has been successfully applied in the design of controllers for small systems could not be applied as is in the design of power system controllers. This thesis proposes a novel approach to the application of the eigenstructure assignment technique in the design of power system controllers. In this new approach, a multi-objective nonlinear optimization problem (MONLOP) is formulated by quantifying different design objectives as a function of free parametric vectors. Then the MONLOP is solved for the free parametric vectors using a nonlinear optimization technique. Finally, the solution of the controller parameters is obtained using the solved free parametric vectors. The superiority of the proposed method over the conventional frequency domain method is demonstrated by designing controllers for three different systems and validating the controllers through nonlinear transient simulations. One of the cases includes design of a PSS for the Manitoba Hydro system having about 29,000 states variables, which demonstrates the applicability of the proposed algorithm for a practical real-world system.

A novel control method called orthogonal eigenstructure control is developed for active vibration cancellation in structures. Orthogonal eigenstructure control is a feedback control method applicable to multi-input multi-output linear systems. While the available control design methodologies offer a large and complex design space of options that can often overwhelm a designer, this control method offers a significant simplification of the design task while still allowing some experience-based design freedom. For example, eigenstructure assignment methods need definition of a desired eigenvector for the closed-loop system. The controller designer may also be required to do pole placement. Considering the fact that there are no one-to-one relationships between the elements of the closed-loop eigenvectors of a model and the states of the system, this effort could be inefficient for many practical systems. Moreover, for large-scale systems, defining or shaping the eigenstructures become a relatively difficult task. Orthogonal eigenstructure control is a state feedback-like control law that is relatively easy to design and implement to multiple-input multiple-output systems. It allows control engineers to achieve good performing designs even with little design experience, while the existing methods are highly dependent on designer experience. Orthogonal eigenstructure control is introduced and extended to be applicable to linear systems regardless of the number and location of the actuators and sensors. Also, the concept of progressive application of the proposed control method for increasing robustness is described. Finally, the result of application of the control method for vibration cancellation of a test plate is investigated through experiments for tonal and wideband disturbances. The results show a significant reduction of vibrations using the orthogonal eigenstructure control with relative ease in finding the control gain matrix. / Ph. D.

Power system stabilizers (PSSs) provide the most economical way to improve damping of electro-mechanical oscillations in electrical power systems. Synchrophasor technology enables the use of remotely measured signals in the PSS allowing for greater flexibility in the design of the PSS. Issues related to the transmission of remote signals should be addressed before implementing such systems in practice. This study investigates two of the data transmission issues: (i) delays, and (ii) data dropout; using a synchrophasor-based PSS designed for a two-area four-generator power system model. A time delayed system is modeled using discrete transformation and the effect of the constant delay on the control action of improving damping of an electro-mechanical oscillation is determined analytically. The effect of random delays and data dropout is investigated using non-linear simulations considering viable remedies to overcome these effects. This research also identifies effective means of using synchrophasor signals for improving the performance of PSSs. Primarily, this research introduces a novel control design algorithm based on eigenstructure assignment that could utilize remotely measured signals to design a robust PSS considering different operating conditions at the design stage. Remote signals could be used as additional inputs to the controller, which introduces extra degrees of freedom. In eigenstructure assignment, these additional degrees of freedom are used to assign eigenvalues and eigenvectors to have adequate damping performance of the system over different operating conditions. The algorithm is formulated as a derivative-free non-linear optimization problem and solved using a single step of optimization by eliminating the use of eigenvalue sensitivities. The proposed algorithm is tested for the 68 bus model of the interconnected New England test system and New York power system. Three different control configurations that use local and remote signals are considered in the design. The algorithm is solved using non-linear simplex optimization considering different initial points for seeking a global solution. Delays in the remote signals are also incorporated into the design. The designed controllers are verified in a non-linear simulation platform. Finally, the reliability of synchrophasor-based PSS is discussed in brief. / February 2016

A review of recent literature and the research effort underlying this dissertation indicates that fractional order differential equations have significant potential to advance dynamical system methods broadly. Particular promise exists in the area of control and estimation, even for systems where fractional order models do not arise “naturally”. This dissertation is aimed at further building of the base methodology with a focus on robust feedback control and state estimation. By setting the mathematical foundation with the fractional derivative Caputo definition, we can expand the concept of the fractional order calculus in a way that enables us to build corresponding controllers and estimators in the state-space form. For the robust eigenstructure assignment, we first examine the conditioning problem of the closed-loop eigenvalues and stability robustnesss criteria for the fractional order system, and we find a unique application of an n-dimensional rotation algorithm developed by Mortari, to solve the robust eigenstructure assignment problem in a novel way. In contradistinction to the existing Fractional Kalman filter developed by using Gru ̈ndwald-Letnikov definition, the new Fractional Kalman filter that we establish by utilizing Caputo definition and our algorithms provide us with powerful means for solving practical state estimation problems for fractional order systems.

No description available.

A diagnosis procedure is an algorithm to detect and locate (isolate) faulty components in a dynamic process. In 1994 the California Air Resource Board released a regulation, called OBD II, demanding a thorough diagnosis system on board automotive vehicles. These legislative demands indicate that diagnosis will become increasingly important for automotive engines in the next few years. To achieve diagnosis, redundancy has to be included in the system. This redundancy can be either hardware redundancy or analytical redundancy. Hardware redundancy, e.g. an extra sensor or extra actuator, can be space consuming or expensive. Methods based on analytical redundancy need no extra hardware, the redundancy here is generated from a process model instead. In this thesis, approaches utilizing analytical redundancy is examined. A literature study is made, surveying a number of approaches to the diagnosis problem. Three approaches, based on both linear and non-linear models, are selected and further analyzed and complete design examples are performed. A mathematical model of an SI-engine is derived to enable simulations of the designed methods.

A designação de estruturas próprias de sistemas dinâmicos com retroação completa de estados ou saídas foi objeto de estudo de muitos pesquisadores durante a segunda metade do século XX. Os trabalhos mais relevantes sobre o tema foram revisados e serviram como base para a elaboração da metodologia apresentada neste trabalho. Que consiste na designação de estruturas próprias desejadas para um sistema linear em malha aberta com a modificação de parâmetros do sistema através da pseudo retroação de saídas devidamente definidas. O método foi aplicado na coxinização de um veículo de passeio. No qual os modos de vibrar de modelos lineares com 7 e 8 graus de liberdade do veículo foram adequados com o intuito de reduzir as acelerações verticais de chassi, características do fenômeno shake de motor e câmbio (faixa de frequência entre 7 e 25 Hz). Para tanto, reduziu-se a participação do grau de liberdade vertical de chassi nos modos com grande participação dos graus de liberdade de motor e massa não suspensa. Os resultados obtidos com a aplicação da metodologia na coxinização foram valores de rigidezes, amortecimentos e características de coxins hidráulicos que resultam na redução significativa da aceleração vertical de chassi, que implica em uma melhora perceptível para o consumidor na qualidade do conforto do veículo. / Eigenstructure assignment using full state or output feedback control had been object of study of many researchers during the second half of XX century. The most important works about eigenstructure assignment were reviewed, specially some applications within aerospace industry, that was the responsible for developing all the theory concerning pole and eigenvector placement. The review of the related theory was also based on the pioneering and most expressive works and were base for the methodology developed and described in this work. Which consists basically on the assignment of some desired eigensctructure of open loop linear systems modifying some parameters of the systems by means pseudo feedback of some outputs into inputs specifically defined. This methodology was applied to a 8 DOF vehicle model, a case of study, in order to adequate the system modes changing engine mounts parameters to improve the vehicle ride comfort, mainly eigenstructures about powertrain shake range frequencies.

O objetivo deste trabalho é investigar o controle ativo de vibração em uma pá inteligente de helicóptero. O desenvolvimento de materiais inteligentes para trabalharem como sensores e atuadores apresentam uma nova alternativa no controle de vibração. A pá de helicóptero é modelada pelo método dos elementos finitos, considerando os movimentos de batimento, flexão no plano de rotação, estiramento axial e torção. O modelo da pá considera também ângulo de torção geométrica, não coincidência entre os eixos, elástico e do centro de gravidade das seções transversais e material isotrópico. O modelo matemático é desenvolvido, e nele é incorporado atuadores piezelétricos distribuídos ao longo da envergadura da pá. O controle ativo de vibração é baseado no controle individual da pá na condição de vôo pairado. As matrizes de elementos finitos são obtidas pelo método de energia e um procedimento de linearização é aplicado às equações resultantes. O carregamento aerodinâmico linearizado é calculado para a condição de vôo pairado e a representação no espaço de estados é usada para o projeto de um controlador. Usou-se a técnica de atribuição da autoestrutura por realimentação de saída no modelo de ordem reduzida, resultado da aplicação do método da expansão por frações parciais. As simulações do modelo em malha aberta e fechada, exibiu boas qualidades de resposta, o que mostra que o controle ativo é uma boa alternativa para a redução de vibrações em helicópteros. / The objective of this work is to investigate the performance of a smart helicopter blade. Developments on smart materials for both sensing and/or actuation have provided a novel alternative in vibration control. The helicopter blade is modeled by the finite element method, considering the motions of flapping, lead-lagging, axial stretching, and torsion. The blade model also considers a pretwist angle, offset between mass and elastic axes, and isotropic material. The helicopter blade mathematical model allows the incorporation of piezoelectric actuators distributed along the blade span. The active vibration control is based on the premise of individual blade control and the investigation is carried out for hovering flight condition the finite element matrices are obtained by energy methods and a linearization procedure is applied to the resulting expressions. The linearized aerodynamic loading is calculated for hover and the state-space approach is used to design the control law. The eigenstructure assignment by output feedback is used in the blade-reduced model resulting from the application of the expansion method by partial fractions. The simulations for open and closed-loop systems are presented, having exhibited good response qualities, which shows that output feedback is a good alternative for smart helicopter blade vibration attenuation.

O objetivo deste trabalho é investigar o controle ativo de vibração em uma pá inteligente de helicóptero. O desenvolvimento de materiais inteligentes para trabalharem como sensores e atuadores apresentam uma nova alternativa no controle de vibração. A pá de helicóptero é modelada pelo método dos elementos finitos, considerando os movimentos de batimento, flexão no plano de rotação, estiramento axial e torção. O modelo da pá considera também ângulo de torção geométrica, não coincidência entre os eixos, elástico e do centro de gravidade das seções transversais e material isotrópico. O modelo matemático é desenvolvido, e nele é incorporado atuadores piezelétricos distribuídos ao longo da envergadura da pá. O controle ativo de vibração é baseado no controle individual da pá na condição de vôo pairado. As matrizes de elementos finitos são obtidas pelo método de energia e um procedimento de linearização é aplicado às equações resultantes. O carregamento aerodinâmico linearizado é calculado para a condição de vôo pairado e a representação no espaço de estados é usada para o projeto de um controlador. Usou-se a técnica de atribuição da autoestrutura por realimentação de saída no modelo de ordem reduzida, resultado da aplicação do método da expansão por frações parciais. As simulações do modelo em malha aberta e fechada, exibiu boas qualidades de resposta, o que mostra que o controle ativo é uma boa alternativa para a redução de vibrações em helicópteros. / The objective of this work is to investigate the performance of a smart helicopter blade. Developments on smart materials for both sensing and/or actuation have provided a novel alternative in vibration control. The helicopter blade is modeled by the finite element method, considering the motions of flapping, lead-lagging, axial stretching, and torsion. The blade model also considers a pretwist angle, offset between mass and elastic axes, and isotropic material. The helicopter blade mathematical model allows the incorporation of piezoelectric actuators distributed along the blade span. The active vibration control is based on the premise of individual blade control and the investigation is carried out for hovering flight condition the finite element matrices are obtained by energy methods and a linearization procedure is applied to the resulting expressions. The linearized aerodynamic loading is calculated for hover and the state-space approach is used to design the control law. The eigenstructure assignment by output feedback is used in the blade-reduced model resulting from the application of the expansion method by partial fractions. The simulations for open and closed-loop systems are presented, having exhibited good response qualities, which shows that output feedback is a good alternative for smart helicopter blade vibration attenuation.