Dynamic Model Construction and Control System Design for Canadian Supercritical Water-cooled Reactors

The dynamic characteristics of Canadian Supercritical Water-cooled Reactor (SCWR) are significantly different from those of CANDU reactors due to the supercritical water coolant and the once-through direct cycle coolant system. Therefore, it is necessary to study its dynamic behaviour and further design adequate control system. An accurate dynamic model is needed to describe the dynamic behaviour. Moving boundary method is applied to improve numerical accuracy and stability. In the model construction process, three regions have been considered depending on bulk and wall temperature being higher or lower than the pseudo-critical temperature. Benefits of adopting moving boundary method are illustrated in comparison with the fixed boundary method. The model is validated with both steady-state and transient simulation and can accurately predict the dynamic behaviour of the Canadian SCWR. A linear dynamic model, for dynamic analysis and control system design, is obtained through linearization on the nonlinear dynamic models derived from conservation equations. The linearized dynamic models are validated against the full order nonlinear models in both time domain and frequency domain. The open-loop dynamics are also investigated through extensive simulations. Cross-coupling analysis among inputs and outputs is examined using Relative Gain Array (RGA) and Nyquist plots, from which adequate input-output pairings are identified. Cross-coupling at different operating conditions are also evaluated to illustrate the nonlinearities. It can be concluded that the Canadian SCWR is a Multiple Input and Multiple Output (MIMO) system with strong cross-coupling and a high degree of nonlinearity. Due to the existence of strong cross-coupling, the Direct Nyquist Array (DNA) method is used to decouple the system into a diagonal dominance form via a pre-compensator. Three Single Input and Single Output (SISO) compensators are synthesized to the pre-compensated system in the frequency domain. The temperature variation induced by the disturbances at the reactor power and pressure can be significantly reduced. To deal with the nonlinearities, a gain scheduling control strategy is adopted. Different set of controllers are used at different load conditions. The control strategy is evaluated under various operating scenarios. It is shown that gain scheduling control can successfully achieve satisfactory performance for different operating conditions

Automated Propulsion Control

Propulsion systems that power the ships of today's navies require some level of operator input. These inputs include manually starting and stopping propulsion engines and adjusting the throttle, which commands the speeds on the engines that power the ship. Ultimately, the job of the operator is to ensure that the ship safely travels at a desired speed. This objective can be achieved without much human interaction, but with the implementation of an automated propulsion controller that is presented in this work.The automated propulsion controller uses hybrid control theory to automatically achieve both the continuous and discrete control objectives of which the operator is usually responsible. The approach presented includes an integrated hybrid controller, which applies the outputs of the continuous control algorithms as inputs to the discrete logic and the outputs of the discrete logic are inputs of the continuous control algorithms. Various continuous control approaches are explored before a rather simplified control approach is implemented. The discrete control logic is designed using a Petri net approach with the objective to align the ship to its optimum configuration. The hybrid controller is modeled, along with a ship propulsion system, to verify its desired functionality and to ensure that the primary control objectives are achieved. In multiple tests, the automated propulsion controller successfully achieved its desired objectives.Ph.D., Mechanical Engineering and Mechanics -- Drexel University, 201

Thermal power plant boiler temperature distribution control based on extremum seeking strategy.

Termoelektrane predstavljaju vec´inske proizvod¯acˇe elektricˇne energije u svetu, što za posledicu ima stalne pokušaje unapred¯enja u vidu smanjenja štetnih uticaja na životnu sredinu uz pove´canje efikasnosti, raspoloživosti i prihoda. Pomenuti efekti su u direktnoj vezi sa procesom sagorevanja, zbog ˇcega su upravljanje i optimizacija ovog procesa od suštinskog znaˇcaja. Ove potrebe su ˇcesto ograniˇcene mogu´cnostima nadgledanja procesa sagorevanja. Obiˇcno se za sagledavanje ovog procesa analizira neko od dostupnih merenja dobijenih iz hemijskih analizatora sadržaja ugljen-monoksida ili kiseonika u dimnim gasovima, što je korisno za ocenu kvaliteta sagorevanja fosilnih goriva. Med¯utim, ovo su globalni pokazatelji i ne govore ništa o lokalnoj raspodeli temperatura unutar ložišta...Thermal power plants are the main producers of electrical energy in the world, and therefore there are constant attempts for improvement in terms of reducing harmful effects on the surroundings, while at the same time increasing eciency, availability and incomes. Aforementioned eects are directly related to the combustion process, which gives great importance to control and optimization of this process. These requirements are usually constrained by the possibilities of combustion process monitoring. This is mainly done by performing the acquisition of available measurements obtained from the chemical analysis of carbon dioxide and oxygen content in the flue gases, which is useful for the evaluation of fossil fuels combustion. However, these are only global indicators and they provide no information about the local temperature distribution inside the furnace..

Microgrids

Microgrids are a growing segment of the energy industry, representing a paradigm shift from centralized structures toward more localized, autonomous, dynamic, and bi-directional energy networks, especially in cities and communities. The ability to isolate from the larger grid makes microgrids resilient, while their capability of forming scalable energy clusters permits the delivery of services that make the grid more sustainable and competitive. Through an optimal design and management process, microgrids could also provide efficient, low-cost, clean energy and help to improve the operation and stability of regional energy systems. This book covers these promising and dynamic areas of research and development and gathers contributions on different aspects of microgrids in an aim to impart higher degrees of sustainability and resilience to energy systems

Optimal Control of Hybrid Systems and Renewable Energies

This book is a collection of papers covering various aspects of the optimal control of power and energy production from renewable resources (wind, PV, biomass, hydrogen, etc.). In particular, attention is focused both on the optimal control of new technologies and on their integration in buildings, microgrids, and energy markets. The examples presented in this book are among the most promising technologies for satisfying an increasing share of thermal and electrical demands with renewable sources: from solar cooling plants to offshore wind generation; hybrid plants, combining traditional and renewable sources, are also considered, as well as traditional and innovative storage systems. Innovative solutions for transportation systems are also explored for both railway infrastructures and advanced light rail vehicles. The optimization and control of new solutions for the power network are addressed in detail: specifically, special attention is paid to microgrids as new paradigms for distribution networks, but also in other applications (e.g., shipboards). Finally, optimization and simulation models within SCADA and energy management systems are considered. This book is intended for engineers, researchers, and practitioners that work in the field of energy, smart grid, renewable resources, and their optimization and control

Dynamic modeling, optimization, and control of integrated energy systems in a smart grid environment

textThis work considers how various integrated energy systems can be managed in order to provide economic or energetic benefits. Energy systems can gain additional degrees of freedom by incorporating some form of energy storage (in this work, thermal energy storage), and the increasing penetration of smart grid technologies provides a wealth of data for both modeling and management. Data used for the system models here come primarily from the Pecan Street Smart Grid Demonstration Project in Austin, Texas, USA. Other data are from the Austin Energy Mueller Energy Center and the University of Texas Hal C. Weaver combined heat and power plant. Systems considered in this work include thermal energy storage, chiller plants, combined heat and power plants, turbine inlet cooling, residential air conditioning, and solar photovoltaics. These systems are modeled and controlled in integrated environments in order to provide system benefits. In a district cooling system with thermal energy storage, combined heat and power, and turbine inlet cooling, model-based optimization strategies are able to reduce peak demand and decrease cooling electricity costs by 79%. Smart grid data are employed to consider a system of 900 residential homes in Austin. In order to make the system model tractable for a model predictive controller, a reduced-order home modeling strategy is developed that maps thermostat set points to air conditioner electricity consumption. When the model predictive controller is developed for the system, the system is able to reduce total peak demand by 9%. Further work with the model of 900 residential homes presents a modified dual formulation for determining the optimal prices that produce a desired result in the residential homes. By using the modified dual formulation, it is found that the optimal pricing strategy for peak demand reduction is a critical peak pricing rate structure, and that those prices can be used in place of centralized control strategies to achieve peak reduction goals.Chemical Engineerin

NASA thesaurus. Volume 3: Definitions

Publication of NASA Thesaurus definitions began with Supplement 1 to the 1985 NASA Thesaurus. The definitions given here represent the complete file of over 3,200 definitions, complimented by nearly 1,000 use references. Definitions of more common or general scientific terms are given a NASA slant if one exists. Certain terms are not defined as a matter of policy: common names, chemical elements, specific models of computers, and nontechnical terms. The NASA Thesaurus predates by a number of years the systematic effort to define terms, therefore not all Thesaurus terms have been defined. Nevertheless, definitions of older terms are continually being added. The following data are provided for each entry: term in uppercase/lowercase form, definition, source, and year the term (not the definition) was added to the NASA Thesaurus. The NASA History Office is the authority for capitalization in satellite and spacecraft names. Definitions with no source given were constructed by lexicographers at the NASA Scientific and Technical Information (STI) Facility who rely on the following sources for their information: experts in the field, literature searches from the NASA STI database, and specialized references