Dissertations / Theses: 'Electric Power Systems - Control Theory'

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Parsi-Feraidoonian, Raiomand. "Application of catastrophe theory to transient stability analysis of multimachine power systems." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29723.

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Transient stability analysis is an important part of power planning and operation. For large power systems, such analysis is very time consuming and expensive. Therefore, an online transient stability assessment will be required as these large power systems are operated close to their maximum limits. In this thesis swallowtail catastrophe is used to determine the transient stability regions. The bifurcation set represents the transient stability region in terms of power system transient parameters bounded by the transient stability limits. The system modelling is generalized in such, that the analysis could handle either one or any number of critical machines. This generalized model is then tested on a three-machine as well as a seven-machine system. The results of the stability analysis done with the generalized method is compared with the time solution and the results were satisfactory. The transient stability regions determined are valid for any changes in loading conditions and fault location. This method is a good candidate for on-line assessment of transient stability of power systems.
Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate

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Dafis, Chris J. Nwankpa Chika O. "An observability formulation for nonlinear power systems modeled as differential algebraic systems /." Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/519.

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Popli, Nipun. "Multi-layered Energy Conversion and Frequency Control in Complex Electric Power Systems." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/916.

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The main performance objective in an electric power grid entails timely and efficient generation and delivery to the time-varying electricity demand. As the electricity industry is witnessing proliferation of the mainstream renewables, the minute-by-minute variations in wind and solar power generation may result in temporary electricity scarcity that jeopardizes grid stability and quality of service. The evolving electricity markets are aimed at incentivizing the conventional generators to reinforce their operating flexibility. This dissertation concerns the goal of enhancing the dynamic response rates of interconnected controllable resources by means of a multi-layered fuel input control of electrically coupled heterogeneous energy conversion components. Both power engineering and large-scale control contributions are made in support of this enhancement. First, improved fuel input controls are designed to enable flexible physics-based energy conversion dynamics required by the interconnected grid. To efficiently utilize the resources load-following and regulation problems are stated. The efficacy of proposed fuel input control designs in enhancing the dynamic response rates is illustrated on IEEE 14-bus system. Second, the problem is formalized as multi-input multioutput time-varying trajectory tracking based on a decentralized spatiotemporal composite control design. The concepts of vector-Lyapunov function and singular perturbation are invoked to formalize model decompositions, over space and time, respectively. Next, the assumptions for model simplifications are relaxed and the problem of parametric uncertainty is addressed. A minimumcost resilient co-design approach is introduced for storage-sensors-communication channels in a complex electric power grid. The notion of selective strong structural fixed modes is explored as a characterization of feasible decentralized control laws for an arbitrary system realization satisfying a pre-specified structure. Finally, it is proposed that planning of generation portfolio must be driven by the objective of maintaining adequate operating flexibility in the system. The goal is to ensure sufficient ramp capacity to sustain the significant integration of intermittent renewable resources.

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He, Fangpo. "Nonlinear adaptive control in the design of power system stabilisers /." Title page, contents and introduction only, 1991. http://web4.library.adelaide.edu.au/theses/09PH/09phh431.pdf.

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Zonetti, Daniele. "Energy-based modelling and control of electric power systems with guaranteed stability properties." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS118/document.

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Pour traiter les systèmes non linéaires, à grande échelle, multi-domaine tels que les systèmes électriques de puissance, nous avons remarqué dans les dernières années un intérêt croissant pour les techniques de modélisation, analyse et contrôle basées sur la notion d'énergie. L'énergie est en fait un concept fondamental en science et en ingénierie, où typiquement les systèmes dynamiques sont regardés comme des dispositifs de transformation d'énergie. Cette perspective est particulièrement utile pour étudier des systèmes non linéaires assez complexes, qui peuvent être décomposés en sous-systèmes plus simples, caractérisés au niveau énergétique, et qui, à travers leurs interconnexions, déterminent le comportement global du système tout entier. Il représente bien évidemment le langage le plus naturel et intuitif pour représenter les systèmes électriques de puissance. En particulier, l'utilisation de systèmes Hamiltoniens à Ports a eu un impact très fort dans différentes applications, plus précisément dans le cas de systèmes mécaniques, électriques et électromécaniques. Dans ce contexte alors, l'approche Hamiltonien à Ports représentent sans doute une base solide qui montre une nouvelle fac{c}on d'aborder les problèmes d'analyse et contrôle de systèmes électriques de puissance. Basée sur cette approche, la thèse est structurée en trois étapes fondamentales:1 - Modélisation d'une classe très générale de systèmes électriques de puissance, basée sur la théorie des graphes et la formulation en Systèmes Hamiltoniens à Ports des composantes.2 - Modélisation, analyse et commande de systèmes de transmission de courant continu haute tension. Avec l'intention de construire un pont entre la théorie et les éventuelles applications, un des objectifs fondamentaux consiste à établir des relations évidentes entre les solutions adoptées dans la pratique et les solutions obtenues à travers une analyse mathématique précise.3 - Travaux apparentés de l'auteur, dans différents domaines des systèmes électriques de puissance: systèmes ac conventionnels et micro réseaux
To deal with nonlinear, large scale, multidomain, systems, as power systems are, we have witnessed in the last few years an increasing interest in energy–based modeling, analysis and controller design techniques. Energy is one of the fundamental concepts in science and engineering practice, where it is common to view dynamical systems as energy-transformation devices. This perspective is particularly useful in studying complex nonlinear systems by decomposing them into simpler subsystems which, upon interconnection, add up their energies to determine the full systems behavior. This is obviously the most natural and intuitive language to represent power systems. In particular, the use of port–Hamiltonian (pH) systems has been already proven highly successful in many applications, namely for mechanical, electrical and electromechanical systems. The port-Hamiltonian systems paradigm theremore provides a solid foundation, which suggests new ways to look at power systems analysis and control problems.Based on this framework, this thesis is structured in three main steps.1 - Modelling of a generalized class of electric power systems, based on graph theory and port-Hamiltonian representation of the individual components.2 - Modelling, analysis and control of multiterminal hvdc transmission systems. With the intention to bridge the gap between theory and applications, one of the main concerns is to establish connections between existing engineering solutions, usually derived via ad hoc considerations, and the solutions stemming from theoretical analysis.3 - Additional contributions of the author in other fields of electric power systems, including traditional ac power systems an microgrids

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Poon, Kai-yin Kenny. "An investigation on the application of nonlinear robust adaptive control theory in AC/DC power systems." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38898949.

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Birch, Alan Philip. "Adaptive load frequency control of electrical power systems." Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6448/.

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The thesis describes Load Frequency Control techniques which may be used for real-time on-line control of large electrical power systems. Traditionally the frequency control of power systems has been carried out using standard fixed parameter control schemes, which give control over the immediate steady- state error and the long term accumulated frequency error, but do not account for the fact that system conditions can alter due to the change in consumer load and generating patterns. The thesis presents a method of controlling the system frequency using adaptive control techniques, which ensure that optimal control action is calculated based on the present system conditions. It enables the system operating point to be monitored so that optimal control may continue to be calculated as the system operating point alters. The proposed method of frequency control can be extended to meet the problems of system interconnection and the control of inter-area power flows. The thesis describes the work carried out at Durham on a fixed parameter control scheme which led to the development of an adaptive control scheme. The controller was validated against a real-time power system simulator with full Energy Management software. Results are also presented from work carried out at the Central Electricity Research Laboratories under the C.A.S.E award scheme. This led to the development of a power system simulator, which along with the controller was validated on-line with the Dispatch Project used by the Central Electricity Generating Board.

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Moghaddami, Masood. "Design Optimization of Inductive Power Transfer Systems for Contactless Electric Vehicle Charging Applications." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3853.

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Contactless Electric Vehicle (EV) charging based on magnetic resonant induction is an emerging technology that can revolutionize the future of the EV industry and transportation systems by enabling an automated and convenient charging process. However, in order to make this technology an acceptable alternative for conventional plug-in charging systems it needs to be optimized for different design measures. Specifically, the efficiency of an inductive EV charging system is of a great importance and should be comparable to the efficiency of conventional plug-in EV chargers. The aim of this study is to develop solutions that contribute to the design enhancement of inductive EV charging systems. Specifically, generalized physics-based design optimization methods that address the trade-off problem between several key objectives including efficiency, power density, misalignment tolerance, and cost efficiency considering critical constraints are developed. Using the developed design methodology, a 3.7kW inductive charging system with square magnetic structures is investigated as a case study and a prototype is built to validate the optimization results. The developed prototype achieves 93.65% efficiency (DC-to-DC) and a power density of 1.65kW/dm3. Also, self-tuning power transfer control methods with resonance frequency tracking capability and bidirectional power transfer control are presented. The proposed control methods enhance the efficiency of power converters and reduce the Electromagnetic Interference (EMI) by enabling soft-switching operations. Several simplified digital controllers are developed and experimentally implemented. The controllers are implemented without the use of DSP/FPGA solutions. Experimental tests show that of the developed simplified controllers can effectively regulate the power transfer around the desired value. Moreover, the experiments show that compared to conventional converters, the developed converters can achieve 4% higher efficiency at low power levels. Moreover, enhanced matrix converter topologies that can achieve bidirectional power transfer and high efficiency with a reduced number of switching elements are introduced. The self-tuning controllers are utilized to design and develop control schemes for bidirectional power transfer regulation. The simulation analyses and experimental results show that the developed matrix converters can effectively establish bidirectional power transfer at the desired power levels with soft-switching operations and resonance frequency tracking capability. Specifically, a direct three-phase AC-AC matrix converter with a reduced number of switches (only seven) is developed and built. It is shown that the developed converters can achieve efficiencies as high as 98.54% at high power levels and outperform conventional two-stage converters.

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Pourbeik, Pouyan. "Design and coordination of stabilisers for generators and FACTS devices in multimachine power systems /." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09php877.pdf.

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Poon, Kai-yin Kenny, and 潘啟然. "An investigation on the application of nonlinear robust adaptive control theory in AC/DC power systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38898949.

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Pan, Fei. "Multifrequency Averaging in Power Electronic Systems." UKnowledge, 2014. http://uknowledge.uky.edu/ece_etds/62.

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Power electronic systems have been widely used in the electrical power processing for applications with power levels ranging from less than one watt in battery-operated portable devices to more than megawatts in the converters, inverters and rectifiers of the utility power systems. These systems typically involve the passive elements such as inductors, capacitors, and resistors, the switching electronic components such as IGBTs, MOSFETS, and diodes, and other electronic circuits. Multifrequency averaging is one of the widely used modeling and simulation techniques today for the analysis and design of power electronic systems. This technique is capable of providing the average behavior as well as the ripple behavior of power electronic systems. This work begins with the extension of multifrequency averaging to represent uniformly sampled PWM converters. A new multifrequency averaging method of solving an observed issue with model stability is proposed and validated. Multifrequency averaging can also be applied to study the instability phenomenon in power electronic systems. In particular, a reduced-order multifrequency averaging method, along with a genetic algorithm based procedure, is proposed in this work to estimate the regions of attraction of power electronic converters. The performance of this method is shown by comparing the accuracy and efficiency with the existing methods. Finally, a new continuous-time multifrequency averaging method of representing discrete-time systems is proposed. The proposed method is applied to model digitally controlled PWM converters. Simulation and hardware results show that the proposed method is capable of predicting the average behavior as well as the ripple behavior of the closed-loop systems. Future research in the area of multifrequency averaging is proposed.

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Ma, Tan. "Hybrid Power System Intelligent Operation and Protection Involving Plug-in Electric Vehicles." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/1760.

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Two key solutions to reduce the greenhouse gas emissions and increase the overall energy efficiency are to maximize the utilization of renewable energy resources (RERs) to generate energy for load consumption and to shift to low or zero emission plug-in electric vehicles (PEVs) for transportation. The present U.S. aging and overburdened power grid infrastructure is under a tremendous pressure to handle the issues involved in penetration of RERS and PEVs. The future power grid should be designed with for the effective utilization of distributed RERs and distributed generations to intelligently respond to varying customer demand including PEVs with high level of security, stability and reliability. This dissertation develops and verifies such a hybrid AC-DC power system. The system will operate in a distributed manner incorporating multiple components in both AC and DC styles and work in both grid-connected and islanding modes. The verification was performed on a laboratory-based hybrid AC-DC power system testbed as hardware/software platform. In this system, RERs emulators together with their maximum power point tracking technology and power electronics converters were designed to test different energy harvesting algorithms. The Energy storage devices including lithium-ion batteries and ultra-capacitors were used to optimize the performance of the hybrid power system. A lithium-ion battery smart energy management system with thermal and state of charge self-balancing was proposed to protect the energy storage system. A grid connected DC PEVs parking garage emulator, with five lithium-ion batteries was also designed with the smart charging functions that can emulate the future vehicle-to-grid (V2G), vehicle-to-vehicle (V2V) and vehicle-to-house (V2H) services. This includes grid voltage and frequency regulations, spinning reserves, micro grid islanding detection and energy resource support. The results show successful integration of the developed techniques for control and energy management of future hybrid AC-DC power systems with high penetration of RERs and PEVs.

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Alawhali, Nasser. "CONTRIBUTIONS TO HYBRID POWER SYSTEMS INCORPORATING RENEWABLES FOR DESALINATION SYSTEMS." UKnowledge, 2018. https://uknowledge.uky.edu/ece_etds/115.

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Renewable energy is one of the most reliable resource that can be used to generate the electricity. It is expected to be the most highly used resource for electricity generation in many countries in the world in the next few decades. Renewable energy resources can be used in several purposes. It can be used for electricity generation, water desalination and mining. Using renewable resources to desalinate the water has several advantages such as reduce the emission, save money and improve the public health. The research described in the thesis focuses on the analysis of using the renewable resources such as solar and wind turbines for desalination plant. The output power from wind turbine is connected through converter and the excess power will be transfer back to the main grid. The photo-voltaic system (PV) is divided into several sections, each section has its own DC-DC converter for maximum power point tracking and a two-level grid connected inverter with different control strategies. The functions of the battery are explored by connecting it to the system in order to prevent possible voltage fluctuations and as a bu er storage in order to eliminate the power mismatch between PV array generation and load demand. Computer models of the system are developed and implemented using the PSCADTM / EMTDCTM software.

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Johal, Harjeet. "Distributed series reactance a new approach to realize grid power flow control /." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26713.

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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Divan, Deepakraj M.; Committee Member: Begovic, Miroslav M.; Committee Member: Brown, Marilyn; Committee Member: Harley, Ronald G.; Committee Member: Wolf, Wayne H. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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Zhao, Huiying. "Regulation and Control of AC Microgrid Systems with Renewable Generation and Battery Energy Storage System." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1536342769000338.

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Mota, Daniel dos Santos. "Técnicas de ajuste de estabilizadores de sistemas de potência." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-24012010-103221/.

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Esta dissertação apresenta técnicas de ajuste de estabilizadores de sistemas de potência (PSS) com um enfoque nos desafios encontrados por um engenheiro durante o comissionamento do sistema de excitação estático de uma unidade geradora de médio porte. Os métodos de ajuste tratados neste trabalho são principalmente os aplicáveis aos estabilizadores do tipo PSS2B. É dada prioridade às situações nas quais o engenheiro não dispõe de dados detalhados do modelo do gerador e do sistema de potência. Simulações computacionais nos domínios do tempo e da frequência são empregadas com objetivos didáticos ao longo do texto. A estrutura do PSS2B é detalhada, explicitando-se a função de cada parâmetro. São apresentados diferentes métodos de estabilizadores, dentre eles ressaltam-se: os métodos de comparação de grandezas no domínio do tempo e o método de compensação de fase. São mostrados resultados práticos obtidos durante comissionamentos em duas usinas hidrelétricas distintas. Comparam-se os diferentes métodos com o auxílio destes resultados práticos e de simulações computacionais
This work presents techniques for tuning power system stabilizers (PSS) with focus on the challenges faced by an engineer during the commissioning of a static excitation system of a medium sized hydro generator. The tuning methods discussed in this study are primarily those applicable to the PSS2B stabilizers. Priority is given to circumstances in which the engineer does not have a detailed model of the generator and power system. Computer simulations in the time and frequency domains are presented with didactic purposes throughout the text. The structure of PSS2B is detailed, the function of each parameter is explained. Among the different methods for tuning the PSS2B, two approaches stand out: the methods based on the comparison of magnitudes in the time domain and the method of phase compensation. The practical results obtained during commissioning of two hydroelectric power plants are presented. The different PSS tuning methods are compared with the aid of these practical results and computer simulations.

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Liu, Xiao. "Power control of single-stage PV inverter for distribution system volt-var optimization." UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/36.

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The output power variability of intermittent renewable sources can cause significant fluctuations in distribution system voltages. A local linear controller that exploits the capability of a photovoltaic inverter to provide both real and reactive power is described. This controller substitutes reactive power for real power when fluctuations in the output of the photovoltaic source are experienced. In this way, the inverter can help mitigate distribution system voltage fluctuations. In order to provide real and reactive to the grid, a three-phase grid-connected single-stage photovoltaic system with maximum power point tracking and power control is described. A method of reducing the current harmonic caused by resonance of the LC filter and transformer is presented. The local linear controller is examined using an example distribution system, and it is found that the controller is effective at mitigating voltage violations. The photovoltaic control system is examined using three-phase single-stage PV inverter system. The power control and damping system show good performance and stability under rapid change of irradiance.

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Flath, Allen III. "Mathematical Programming Approach for the Design of Satellite Power Systems." UKnowledge, 2019. https://uknowledge.uky.edu/ece_etds/136.

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Satellite power systems can be understood as islanded dc microgrids supplied by specialized and coordinated solar cell arrays augmented by electrochemical battery systems to handle high-power loads and periods of eclipse. The periodic availability of power, the limited capacity of batteries, and the dependence of all mission service on power consumption create a unique situation in which temporal power and energy scarcity exist. A multi-period model of an orbital satellite power system’s performance over a mission’s duration can be constructed. A modular power system architecture is used to characterize the system’s constraints. Using mathematical programming, an optimization problem can be posed such that the optimal power and energy ratings for the power system are determined for any load schedule imposed by a given mission’s requirements. The optimal energy trajectory of the electrical power system over a mission’s duration is also determined when the mathematical programming problem is solved. A generic set of mission requirements is identified to test this approach, but the objective function of the resulting optimization problem can be modified to return different results. These results can provide a clear illustration of the trade-offs that designers of such power systems consider in the design process.

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Akeyo, Oluwaseun M. "ANALYSIS AND SIMULATION OF PHOTOVOLTAIC SYSTEMS INCORPORATING BATTERY ENERGY STORAGE." UKnowledge, 2017. http://uknowledge.uky.edu/ece_etds/107.

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Solar energy is an abundant renewable source, which is expected to play an increasing role in the grid's future infrastructure for distributed generation. The research described in the thesis focuses on the analysis of integrating multi-megawatt photovoltaics (PV) systems with battery energy storage into the existing grid and on the theory supporting the electrical operation of components and systems. The PV system is divided into several sections, each having its own DC-DC converter for maximum power point tracking and a two-level grid connected inverter with different control strategies. The functions of the battery are explored by connecting it to the system in order to prevent possible voltage fluctuations and as a buffer storage in order to eliminate the power mismatch between PV array generation and load demand. Computer models of the system are developed and implemented using the PSCADTM/EMTDCTM software.

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Sibal, Edward Constant. "SMART WALL PLUG DESIGN FOR THE DC HOUSE PROJECT." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/892.

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The DC House project at Cal Poly State University faces a challenge of supplying DC voltage to household appliances. Each appliance in the DC House constitutes a DC load that has a unique voltage and power rating, hence the need to develop a smart DC wall plug that will automatically adjust to the operating voltage required by any DC load. This thesis entails a proof of concept design of the smart DC wall plug which can automatically detect an appliance’s voltage rating. The design employs a dc-dc converter in conjunction with a microcontroller to sense load current to properly adjust the required load voltage. Hardware implementation to demonstrate the functionality of the smart wall plug was developed. Results performed on several dc loads show that the smart wall plug is able to adjust to the required load voltage within an acceptable range. An algorithm to improve the accuracy was attempted and presented along with the results. Further recommendations to improve the current design will also be discussed.

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de, Azevedo Ricardo. "Fully Decentralized Multi-Agent System for Optimal Microgrid Control." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2461.

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In preparation for the influx of renewable energy sources that will be added to the electrical system, flexible and adaptable control schemes are necessary to accommodate the changing infrastructure. Microgrids have been gaining much attention as the main solution to the challenges of distributed and intermittent generation, but due to their low inertia, they need fast-acting control systems in order to maintain stability. Multi-Agent Systems have been proposed as dynamic control and communication frameworks. Decentralized arrangements of agents can provide resiliency and the much-desired “plug and play” behavior. This thesis describes a control system that implements droop control and the diffusion communication scheme without the need of a centralized controller to coordinate the Microgrid agents to maintain the frequency and stable operating conditions of the system. Moreover, the inter-agent communication is unaffected by changing network configurations and can achieve optimal economic dispatch through distributed optimization.

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El-Sedawi, I. R. M. "Hierarchical control for electric power systems." Thesis, City University London, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379642.

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Herbig, Arnim. "On load flow control in electric power systems." Doctoral thesis, KTH, Electric Power Systems, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2919.

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Yamamoto, Kazusa. "Control of electromechanical systems, application on electric power steering systems." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT069/document.

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De nos jours, la plupart des véhicules sont équipés de Directions Assistées Electriques (DAE). Ce type de systèmes d'aide à la conduite permet de réduire les efforts que le conducteur doit fournir pour tourner les roues. Ainsi, grâce à un moteur électrique, la DAE applique un couple additionnel en accord avec le comportement du conducteur et la dynamique du véhicule. Il est donc nécessaire de développer une commande en couple basée en particulier sur le signal provenant d'un capteur mesurant le couple agissant au niveau de la barre de torsion (correspondant à une image du couple conducteur). Ce composant est donc essentiel au fonctionnement de la DAE. Or, une défaillance de ce capteur entraine le plus souvent une coupure de l'assistance, pouvant mener à un risque d'accidents. Au regard de la sécurité fonctionnelle, un développement d'un mode de sécurité est recommandé, par de plus en plus de constructeurs automobiles. D'autre part, le marché des équipementiers automobiles reste un secteur très concurrentiel où une baisse des coûts de production est un challenge constamment recherché afin de gagner de nouvelles parts de marchés. Cet aspect de réduction du nombre de capteurs et d'analyse de la dynamique du véhicule s'inscrit donc dans le prolongement de la stratégie de sécurité. Cette thèse, menée au sein de JTEKT Europe, aborde ces divers enjeux. Après une présentation des différents systèmes de directions assistés électriques, des modèles sont présentés pour être utilisés lors de la conception de lois de commande et d'estimateurs. Ensuite deux méthodes d'estimation du couple conducteur sujet aux perturbations de la route et aux bruits de mesures sont proposées : la première est un observateur proportionnel intégral (PI) à synthèse mixte $H_infty/H_2$, et la seconde une approche par filtrage $H_infty$. Puis plusieurs stratégies de commande sont proposées suivant deux cas de figures distincts, soit en utilisant un observateur PI qui estime les états du système et le couple conducteur (LQR, commande LPV par retour d'état), soit en faisant abstraction d'estimateur de couple conducteur (commande $H_infty$ par retour de sortie dynamique). Ce dernier aspect présente l'avantage de nécessiter moins de mesures que le précédent. Ces approches ont été validées en simulation et mises en œuvre sur un véhicule prototype où des résultats prometteurs ont été obtenus
Nowadays, modern vehicles are equipped with more and more driving assistance systems, among them Electric Power Steering (EPS) helps the driver to turn the wheels. Indeed, EPS provides through an electric motor, an additional torque according to the driver's behaviour and the vehicle's dynamics to reduce the amount of effort required to the driver. Therefore, a torque control is developed based on the torque sensor signal which measures in practice the torsion bar torque (corresponding to an image of the driver torque). Consequently, this component is essential to the functioning of EPS systems.Indeed, a torque sensor failure usually leads to shut-off the assistance which may increase the risk of accident. Regarding functional safety, a back-up mode is recommended and required by more and more car manufacturers. On the other hand, a major challenge for automotive suppliers is to reduce cost production in order to meet growing markets demands and manage in the competitive sector. This issue considering a reduction of sensors' numbers and analysis of vehicle's dynamics is therefore an extension of applying the safety strategy. This thesis, carried out within JTEKT Europe, addresses these various issues.After introducing an overview of the different EPS systems, some models used for the design of controllers and estimators are presented. Then, two methods to estimate the driver torque subject to road disturbances and noise measurements are proposed: the first is a proportional integral observer (PI) with mixed synthesis $H_infty / H_2 $, whereas the second is an $ H_infty $ filtering approach. Then, several control strategies are proposed according to two different cases, either by using a PI observer which estimates the system states and the driver torque (LQR, LPV feedback control) or by not taking into account the driver torque estimation ($ H_infty $dynamic output feedback control). This latter approach has the advantage to require less measurements than the previous one. These approaches have been validated in simulation and implemented on a prototype vehicle where promising results have been obtained

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Jiang, Haibo. "Robust control strategies for the transient control of interconnected power systems." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/15728.

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Khare, Rahul. "An operator assistant for emergency control of large-scale power systems /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/6123.

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Chan, Ting. "Analytical methods for power monitoring and control in an underwater observatory /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/6053.

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Wu, Qiang. "Dynamics and coordinated control of voltage behavior in power systems." Thesis, The University of Sydney, 2000. https://hdl.handle.net/2123/27766.

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This thesis presents results on the dynamics and coordinated control of voltage behavior in power systems. The first part of the thesis is on dynamic modeling, with emphasis on tap-changing transformers and load dynamics. For both, highly simplified models are used in voltage stability analysis, despite the complex nature of the devices involved, i.e. tap changing operation and aggregate load. The operating conditions, under which the stability results based on these simplified models are reliable need to be clarified. A study is carried out on the influence of diiferent discrete and continuous tap models on voltage stability properties, particularly when combined with load dynamics. It has been found that small disturbance analysis, especially if based on the common continuous tap model with fixed time constant, is often an unreliable indicator of system stability. Some important differences in system responses with continuous and discrete tap models are highlighted along with the conditions under which they occur. Limit cycles are shown to characterize the system responses with discrete tap models. The limit cycles originate from the deadband nonlinearity embedded in the discrete tap operation and tap-load interactions. Describing functions for the nonlinearity of the discrete tap operation are derived and used to predict the existence of limit cycles. Furthermore, the feasibility of avoiding the limit cycles through adjusting deadband size is investigated. It has been shown that whether or not increasing deadband can always eliminate the existing limit cycle depends on the associated load dynamics. Following this, attention is given to load dynamics modeling. The focus is on use of generic dynamic load models. A simulation study is given on system behavior with generic dynamic loads as compared with the detailed physically based load models which they ap— proximate. Several simple and a more complicated load structures are considered, which include lower voltage tap changers, induction motors, thermostatically controlled heating and static load. It has been shown, for simple load structures, generic dynamic load models, if the parameters are properly identified, provide fairly accurate prediction of system stability behavior in all cases except the one with high percentage of induction motors. On the other hand, for a load structure with diverse compositions, generic dynamic load models have practically useful accuracy for representing the load. This suggests that ap— plying generic dynamic load models will be practically useful in reducing the complexity of system modeling and give reliable stability analysis results. The second part of the thesis is devoted to coordinated voltage control. A general frame work for coordinating optimally a diverse set of control actions is established. The benefit of control coordination is illustrated through a case study on coordination of capacitor switching and tap locking. By careful coordination of these controls, voltage collapse can be arrested with less overall control effort and less impact on the voltage profile than by either acting along. An analytical framework for coordinated voltage control based on coordination of dissimilar control actions is then presented. A 4-stage optimal control scheme is proposed along with detailed formulations. In the first three stages, a security constrained steady—state approach is used to define the optimal control direction for providing stability and adequate security margin. An algorithm based on differential dynamic programming based is then used to optimally schedule controls with different response time and dynamics. Finally, the dynamic sensitivity-based method is employed to refine the obtained control sequence; in terms of finding the optimal switching times for the control actions identified in earlier stages. In the final study of the thesis, application is made of the stability analysis and coordinated control techniques to a substantial physical power system, namely the New South Wales power grid. The algorithm and techniques proposed in previous chapters is tested in a more practical situation.

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Cote, James W. "Voltage security assessment and control in electric power systems /." Thesis, Connect to this title online; UW restricted, 1992. http://hdl.handle.net/1773/5925.

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Cheung, Siu-pan. "Direct transient stability margin assessment of power system with excitation control and SVC control /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1753706X.

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張小彬 and Siu-pan Cheung. "Direct transient stability margin assessment of power system with excitation control and SVC control." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31212979.

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Lee, Seung Jae. "Configuration control of distribution feeders in normal and emergency states /." Thesis, Connect to this title online; UW restricted, 1988. http://hdl.handle.net/1773/5923.

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Alvarez, Rogelio E. "Interdicting electrical power grids." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FAlvarez.pdf.

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Thesis (M.S. in Operations Research)--Naval Postgraduate School, March 2004.
Thesis advisor(s): Javier Salmeron, R. Kevin Wood. Includes bibliographical references (p. 69-70). Also available online.

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Choi, Byungcho. "Dynamics and control of switchmode power conversions in distributed power systems." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06062008-171616/.

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Hu, Dongchen. "A wide-area control for mitigating angle instability in electric power systems." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/d_hu_091406.pdf.

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36

Gonçalves, de Oliveira Janaína. "Power Control Systems in a Flywheel based All-Electric Driveline." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-157074.

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Flywheel systems are attractive in hybrid and electric vehicles due to their ability to handle power during acceleration and braking. The combination of a flywheel device with a battery source has several advantages such as high peak power capacity, high energy density and reduction in the number of charge/discharge cycles of the battery. A flywheel based all-electric driveline is investigated in this thesis. The novelty of the system consists in the use of a double wound flywheel machine, which divides the system in two different power levels. Due to this configuration, the system becomes efficient and can handle the power developed during fast dynamical processes. The complete driveline consists of three main components: the battery, the flywheel machine and the wheel motor. The High-Power (HP) side of the driveline connects the flywheel machine to the wheel motor, whereas the Low-Power (LP) side connects the flywheel machine to the battery. The connections of different components of the system are made electrically through power converter devices. The present thesis focuses on the electrical converters and control strategies used in the flywheel based all-electric driveline. The control of power converters is responsible for the logic and functionality of the driveline, being a challenging step within this project. Different power converter topologies have been investigated: a DC/DC plus a DC/AC converter on the LP side, and an AC/DC/AC converter on the HP side. The design and assembly of the power electronics and their control scheme have been successfully implemented. Different control strategies have been suggested and a complete scaled driveline has been assembled and tested based on previous simulation results. Results have confirmed the functionality of the driveline, where smoothed output power has been obtained from the battery, whereas the flywheel handles power transients on the traction side. An average efficiency of about 87% (battery to wheels) has been obtained. The power converter systems have been shown to be efficient and robust, with control strategies able to handle the peak energy flow in the system. A regenerative braking strategy has been simulated and a wheel-to-wheel efficiency of about 80% has been estimated.

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Eidson, Donald Brian. "Estimation and hierarchical control of market-driven electric power systems." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11068.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.
Includes bibliographical references (leaves 328-337).
by Donald Brian Eidson.
Ph.D.

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Yu, Chien-Ning 1970. "Real power and frequency control of large electric power systems under open access." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38154.

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Atić, Nedz̆ad. "Model predictive control design for load frequency control problem." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=3192.

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Thesis (M.S.)--West Virginia University, 2003.
Title from document title page. Document formatted into pages; contains vii, 68 p. : ill. Includes abstract. Includes bibliographical references (p. 66-68).

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Rabee, Safaa Al-Dbin Hussein. "Power control optimisation for CDMA cellular radio systems." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270810.

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曾坤明 and Kwan-ming Tsang. "Decoupling and stabilizing control of multi-machine power systems withstatic VAr compensators." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B31211008.

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Kirawanich, Phumin. "Fuzzy logic control for an active power line conditioner /." free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060114.

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43

Radan, Damir. "Integrated Control of Marine Electrical Power Systems." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1984.

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This doctoral thesis presents new ideas and research results on control of marine electric power system.

The main motivation for this work is the development of a control system, power management system (PMS) capable to improve the system robustness to blackout, handle major power system faults, minimize the operational cost and keep the power system machinery components under minimal stress in all operational conditions.

Today, the electric marine power system tends to have more system functionality implemented in integrated automation systems. The present state of the art type of tools and methods for analyzing marine power systems do only to a limited extent utilize the increased knowledge available within each of the mechanical and electrical engineering disciplines.

As the propulsion system is typically consisted of the largest consumers on the vessel, important interactions exists between the PMS and vessel propulsion system. These are interacted through the dynamic positioning (DP) controller, thrust allocation algorithm, local thruster controllers, generators' local frequency and voltage controllers. The PMS interacts with the propulsion system through the following main functions: available power static load control, load rate limiting control and blackout prevention control (i.e. fast load reduction). These functions serve to prevent the blackout and to ensure that the vessel will always have enough power.

The PMS interacts with other control systems in order to prevent a blackout and to minimize operational costs. The possibilities to maximize the performance of the vessel, increase the robustness to faults and decrease a component wear-out rate are mainly addressed locally for the individual control systems. The solutions are mainly implicative (for e.g. local thruster control, or DP thrust allocation), and attention has not been given on the interaction between these systems, the power system and PMS. Some of the questions that may arise regarding the system interactions, are as follows: how the PMS functionality may affect a local thruster control, how the local thruster control may affect the power system performance, how some consumers may affect the power system performance in normal operations and thus affect other consumers, how the power system operation may affect the susceptibility to faults and blackout, how various operating and weather conditions may affect the power system performance and thus propulsion performance though the PMS power limiting control, how propulsion performance may affect the overall vessel performance, which kind of faults can be avoided if the control system is re-structured, how to minimize the operational costs and to deal with the conflicting goals. This PhD thesis aims to provide answers to such questions.

The main contributions of this PhD thesis are:

− A new observer-based fast load reduction system for the blackout prevention control has been proposed. When compared to the existing fast load reduction systems, the proposed controller gives much faster blackout detection rate, high reliability in the detection and faster and more precise load reduction (within 150 miliseconds).

− New advanced energy management control strategies for reductions in the operational costs and improved fuel economy of the vessel.

− Load limiting controllers for the reduction of thruster wear-out rate. These controllers are based on the probability of torque loss, real-time torque loss and the thruster shaft

accelerations. The controllers provide means of redistributing thrust from load fluctuating thrusters to less load fluctuating ones, and may operate independently of the thrust allocation system. Another solution is also proposed where the load limiting controller based on thrust losses is an integrated part of DP thrust allocation algorithm.

− A new concept of totally integrated thrust allocation system, local thruster control and power system. These systems are integrated through PMS functionality which is contained within each thruster PLC, thereby distributed among individual controllers, and independent of the communications and dedicated controllers.

− Observer-based inertial controller and direct torque-loss controller (soft anti-spin controller) with particular attention to the control of machine wear-out rate. These controller contribute to general shaft speed control of electrical thrusters, generators and main propulsion prime movers.

The proposed controllers, estimators and concepts are demonstrated through time-domain simulations performed in MATLAB/SIMULINK. The selected data are typical for the required applications and may differ slightly for the presented cases.

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Eriksson, Robert. "Security-centered Coordinated Control in AC/DC Transmission Systems." Licentiate thesis, Stockholm : Royal Institute of Technology, 2008. http://kth.diva-portal.org/smash/record.jsf?searchId=4&pid=diva2:101.

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45

ABDULLA, ABDULLA I. M. "SOME NEW TECHNIQUES FOR THE LOAD FREQUENCY CONTROL OF MULTI-AREA POWER SYSTEMS." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183902.

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In this dissertation, the problem of multi-area load frequency control in large power systems is investigated. The load frequency control problem is concerned with the minimization of the deviations in the frequencies of the different areas and in the tie line power exchange between these areas, and is a problem of major importance in the satisfactory operation of large power systems. Some new techniques for designing load frequency control systems are presented through the use of concepts from singular perturbation and hierarchical system theory. To provide appropriate vehicles for the design of the new control systems, state variable models for power systems are developed. These models progress from a two-area interconnected power system model to large scale models comprising of N areas. Two centralized state feedback schemes are proposed for the load frequency control by utilizing the separation of the system models into two time scales. In the first scheme, composite controls and reduced order controls are developed to meet the required performance specifications by. The second scheme is obtained by using the theory of variable structure systems where the existence of a sliding regime leads to the design of a single discontinuous state feedback controller that meets the performance requirements. In order to further improve the performance of the closed loop system, a two level hierarchical control scheme is developed. This consists of a set of local controllers that are designed using either the singular perturbation approach or the variable structure system approach as before and a set of global control functions provided by a higher level controller that attempts to coordinate the local controllers. The interaction prediction principle is used as a tool in the design of the global controller. The performance of the presently developed control schemes is examined in detail for the illustrative cases of a two-area and a three-area power system. From this analysis, it is shown that these controllers provide an improved performance compared to the existing control schemes in reducing the frequency and tie line power deviations.

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Jung, Ju-Hwan. "Intelligent systems for strategic power infrastructure defense /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/5971.

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47

Newman, Michael John 1976. "Design and control of a Universal Custom Power Conditioner (UCPC)." Monash University, Dept. of Electrical and Computer Systems Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/5651.

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Liu, Xiaojun Zhang. "Structural modeling and hierarchical control of large-scale electric power systems." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12034.

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Begovic, Miroslav M. "Analysis, monitoring and control of voltage stability in electric power systems." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54490.

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The work presented in this text concentrates on three aspects of voltage stability studies: analysis and determination of suitable proximity indicators, design of an effective real-time monitoring system, and determination of appropriate emergency control techniques. A simulation model of voltage collapse was built as analytical tool on 39-bus, 10-generator power system model. Voltage collapse was modeled as a saddle-node bifurcation of the system dynamic model reached by increasing the system loading. Suitable indicators for real-time monitoring were found to be the minimum singular value of power flow Jacobian matrix and generated reactive powers. A study of possibilities for reducing the number of measurements of voltage phasors needed for voltage stability monitoring was also made. The idea of load bus coherency with respect to voltage dynamics was introduced. An algorithm was presented which determines the coherent clusters of load buses in a power system based on an arbitrary criterion function, and the analysis completed with two proposed coherency criteria. Very good agreement was obtained by simulation between the results based on accurate and approximate measurements of the state vector. An algorithm was presented for identification of critical sets of loads in a voltage unstable power system, defined as a subset of loads whose changes have the most pronounced effect on the changes of minimum singular value of load flow Jacobian or generated reactive powers. Effects of load shedding of critical loads were investigated by simulation and favorable results obtained. An investigation was also done by sensitivity analysis of proximity indicators of the effects that locations and amounts of static var compensation have on the stability margin of the system. Static compensation was found to be of limited help when voltage instabilities due to heavy system loading occur in power systems. The feasibility of implementation of the analyses and algorithms presented in this text relies on development of a feasible integrated monitoring and control hardware. The phasor measurement system which was designed at Virginia Polytechnic institute and State University represents an excellent candidate for implementation of real-time monitoring and control procedures.
Ph. D.

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Kang, Rizhong. "Preventive and Corrective Control of Voltage Stability in Electric Power Systems." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/19789.

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This thesis proposes a novel approach aiming to counteract short term voltage fluctuations and transient instability by employing centralized emergency demand response. The objectives in this optimization model include a proposed short-term voltage stability index, inversed transient stability margin and system operation cost. Combined demand response actions of load shedding and load recovery are applied during the corrective period. To reduce computational complexity, load shedding bus candidates are selected based on trajectory sensitivity ranking with respect to the load shedding quantities. Then the optimization model is solved via multi-objective evolutionary algorithms (MOEAs). Compared with existing practices, this work not only coordinates between preventive control (PC) and corrective control (CC) actions, but also considers a proposed user disruption indicator to reflect power supply deviation from nominal demand during load shedding and load recovery periods. A comprehensive three-dimensional Pareto-optimal trade-off solution is computed for decision-making. The proposed method is verified by simulation results on the IEEE 39-bus system.

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Dissertations / Theses on the topic 'Electric Power Systems - Control Theory'

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