A methodology of designing a novel sliding surface for a class of large-scale systems with matched and mismatched perturbations is proposed in this thesis. The main idea is that some adaptive mechanisms are embedded both in the sliding surface function and in the controllers, so that not only the mismatched perturbations are suppressed during the sliding mode, but also the information of upper bound of perturbation is not required except the upper bound of perturbation from input channel. The proposed controller of each subsystem contains two parts. The first part is measurable feedback signals, and the second part is an adaptive control mechanism, which is used for overcoming the perturbation of each subsystem as well as interconnections among subsystems. The dynamics of the controlled system can be driven into the sliding surface in a finite time, and the property of asymptotical stability of each subsystem is guaranteed. Two numerical examples are given to demonstrate the feasibility of the proposed methodology.

In this thesis, a sliding mode controller employing a new sliding surface for antilock brake system (ABS) is proposed, its stability is proven formally and its performance is compared with existing sliding mode controllers. The new sliding mode controller uses the integral-derivative surface, which includes error, its derivative and its integral, all at the same time. This and the already existing derivative surface, which includes error and its derivative only, are named zerothorder sliding surfaces. Their stability analysis is done using first-order auxiliary surfaces. Auxiliary surfaces equal the sliding surfaces when derivative of the error becomes zero. The first-order error surface, which includes only the error, and the integral surface, which includes error and its integral, were also designed for comparison. During design, tire brake force response is modelled as an uncertainty. Controllers are simulated on a road with an abrupt change in road coefficient of adhesion. Controller parameters used are optimized, which results in comparable stopping distances while braking on a constant coefficient of adhesion road. Effect of first order actuator dynamics with varying time constants and actuator absolute time delay were considered. Reaching and sliding properties of controllers were also investigated, using results on a constant coefficient of adhesion road. It is observed that zeroth-order sliding surfaces give smoother response for both derivative and integral-derivative cases. As the controllers employing error and derivative surfaces get unstable in the presence of actuator time delay, the integral-derivative surface, proposed in this study, stands as the best controller.

As the cost of land in cities increases, the need to build multistory buildings in close proximity to each other also increases. Sometimes, construction materials, other objects and any projections from a building may also decrease the spacing provided between the buildings. This leads to the problem of pounding of these closely placed buildings when responding to earthquake ground motion. The recent advent of base isolation systems and their use as an efficient earthquake force resisting mechanism has led to their increased use in civil engineering structures. At the same time, building codes that reflect best design practice are also evolving. The movement of these base isolated buildings can also result in building pounding. Since base isolation is itself a relatively new technique, pounding phenomenon in base isolated buildings have not been adequately investigated to date. This study looks at the base isolated response of a single two story building and adjacent two story building systems. Four earthquakes with increasing intensity were used in this study. It was found that it is difficult to anticipate the response of the adjacent buildings due to non- linear behavior of pounding and base isolation. The worst case for pounding was found to occur when a fixed base and base isolated buildings were adjacent to each other.

As the cost of land in cities increases, the need to build multistory buildings in close proximity to each other also increases. Sometimes, construction materials, other objects and any projections from a building may also decrease the spacing provided between the buildings. This leads to the problem of pounding of these closely placed buildings when responding to earthquake ground motion. The recent advent of base isolation systems and their use as an efficient earthquake force resisting mechanism has led to their increased use in civil engineering structures. At the same time, building codes that reflect best design practice are also evolving. The movement of these base isolated buildings can also result in building pounding. Since base isolation is itself a relatively new technique, pounding phenomenon in base isolated buildings have not been adequately investigated to date. This study looks at the base isolated response of a single two story building and adjacent two story building systems. Four earthquakes with increasing intensity were used in this study. It was found that it is difficult to anticipate the response of the adjacent buildings due to non- linear behavior of pounding and base isolation. The worst case for pounding was found to occur when a fixed base and base isolated buildings were adjacent to each other.

付記する学位プログラム名: グローバル生存学大学院連携プログラム / 京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20340号 / 工博第4277号 / 新制||工||1662(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 寶 馨, 教授 角 哲也, 准教授 佐山 敬洋 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

付記する学位プログラム名: グローバル生存学大学院連携プログラム / 京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21056号 / 工博第4420号 / 新制||工||1687(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 寶 馨, 教授 角 哲也, 准教授 佐山 敬洋 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Applications of distributed-power systems are on the rise. They are already used in telecommunication power supplies, aircraft and shipboard power-distribution systems, motor drives, plasma applications, and they are being considered for numerous other applications. The successful operation of these multi-converter systems relies heavily on a stable design. Conventional analyses of power converters are based on averaged models, which ignore the fast-scale instability and analyze the stability on a reduced-order manifold. As such, validity of the averaged models varies with the switching frequency even for the same topological structure. The prevalent procedure for analyzing the stability of switching converters is based on linearized smooth averaged (small-signal) models. Yet there are systems (in active use) that yield a non-smooth averaged model. Even for systems for which smooth averaged models are realizable, small-signal analyses of the nominal solution/orbit do not provide anything about three important characteristics: region of attraction of the nominal solution, dependence of the converter dynamics on the initial conditions of the states, and the post-instability dynamics. As such, converters designed based on small-signal analyses may be conservative. In addition, linear controllers based on such analysis may not be robust and optimal. Clearly, there is a need to analyze the stability of power converters from a different perspective and design nonlinear controllers for such hybrid systems. In this Dissertation, using bifurcation analysis and Lyapunov's method, we analyze the stability and dynamics of some of the building blocks of distributed-power systems, namely standalone, integrated, and parallel converters. Using analytical and experimental results, we show some of the differences between the conventional and new approaches for stability analyses of switching converters and demonstrate the shortcomings of some of the existing results. Furthermore, using nonlinear analyses we attempt to answer three fundamental questions: when does an instability occur, what is the mechanism of the instability, and what happens after the instability? Subsequently, we develop nonlinear controllers to stabilize parallel dc-dc and parallel multi-phase converters. The proposed controllers for parallel dc-dc converters combine the concepts of multiple-sliding-surface and integral-variable-structure control. They are easy to design, robust, and have good transient and steady-state performances. Furthermore, they achieve a constant switching frequency within the boundary layer and hence can be operated in interleaving or synchronicity modes. The controllers developed for parallel multi-phase converters retain many of the above features. In addition, they do not require any communication between the modules; as such, they have high redundancy. One of these control schemes combines space-vector modulation and variable-structure control. It achieves constant switching frequency within the boundary layer and a good compromise between the transient and steady-state performances. / Ph. D.

Made available in DSpace on 2014-12-17T14:56:12Z (GMT). No. of bitstreams: 1 SuelioFC_DISSERT.pdf: 1266723 bytes, checksum: 8001a23164a7a48663a60001950fc3e0 (MD5) Previous issue date: 2013-02-01 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The stability of synchronous generators connected to power grid has been the object of study and research for years. The interest in this matter is justified by the fact that much of the electricity produced worldwide is obtained with the use of synchronous generators. In this respect, studies have been proposed using conventional and unconventional control techniques such as fuzzy logic, neural networks, and adaptive controllers to increase the stabilitymargin of the systemduring sudden failures and transient disturbances. Thismaster thesis presents a robust unconventional control strategy for maintaining the stability of power systems and regulation of output voltage of synchronous generators connected to the grid. The proposed control strategy comprises the integration of a sliding surface with a linear controller. This control structure is designed to prevent the power system losing synchronism after a sudden failure and regulation of the terminal voltage of the generator after the fault. The feasibility of the proposed control strategy was experimentally tested in a salient pole synchronous generator of 5 kVA in a laboratory structure / A estabilidade de geradores s?ncronos conectados a rede el?trica tem sido objeto de estudo e investiga??es durante anos. O interesse por este assunto ? justificado pelo fato de grande parte da energia el?trica produzida no mundo ser obtida com a utiliza??o de geradores s?ncronos. Nesse aspecto, muitos trabalhos t?m sido propostos utilizando t?cnicas de controle convencional e n?o convencional como l?gica fuzzy, redes neurais e controladores adaptativos visando aumentar a margem de estabilidade do sistema quando ele est? sujeito a falhas s?bitas e dist?rbios transit?rios. Este trabalho apresenta uma estrat?gia de controle robusta n?o-convencional para a manuten??o da estabilidade dos sistemas de pot?ncia e regula??o da tens?o de sa?da de geradores s?ncronos conectados ? rede el?trica. A estrat?gia de controle utilizada ? composta pela integra??o de uma superf?cie deslizante com um controlador linear. Esta estrutura de controle contribui para a preven??o dos sistemas de pot?ncia de perder o sincronismo ap?s uma falha s?bita e regula??o da tens?o terminal do gerador ap?s a falta. A viabilidade da estrat?gia de controle proposta foi testada experimentalmente em um gerador s?ncrono de p?los salientes de 5 kVA em uma estrutura de laborat?rio