Dual Mode MPC for a Concentrated Solar Thermal Power Plant

A model predictive control strategy for a concentrated solar thermal power plant is proposed. Design of the proposed controller is based on an estimated linear time-invariant state space model around a nominal operating point. The model is estimated directly from input-output data using the subspace identification method and taking into account the frequency response of the plant. Input-output data are obtained from a nonlinear distributed parameter model of a plant rather than the plant itself. Effectiveness of the proposed control strategy in terms of tracking and disturbance rejection is evaluated through two different scenarios created in a nonlinear simulation environment

Model and control of a solar tower for energy production

Supervisors: Prof./Dr. João Manuel Lage de Miranda Lemos; Prof./Dr. Bertinho Manuel D’Andrade da Costa. Examination Committee: Chairperson: Prof./Dr. João Fernando Cardoso Silva Sequeira;Supervisor: Prof./Dr. João Manuel Lage de Miranda Lemos. Members of the Committee: BGEN/ENGEL Luis Filipe Basto Damásio; TCOR/ENGEL Ana Paula da Silva Jorge; Prof./Dr. Alexandre José Malheiro BernardinSolar towers are electrical power production systems that use highly concentrated solar radiation as energy source that is collected by means of a heat-transfer fluid. This master thesis studies the application of several control strategies with the aim of maintaining the working fluid at a temperature that maximizes the electrical production. The main difficulties are the nonlinear fluid temperature dynamics, plant thermal constrains, and a variable energy source that cannot be manipulated. The temperature dynamics flow dependence demands for a changing parameter controller that results from a gain scheduling scheme or from a multi-model adaptive control strategy, in which the manipulated variable is adjusted by one of the set of local controllers designed for different operating regimes. The former is accomplished through a Proportional-Integral Controller (PI) control and the latter via Linear Quadratic Gaussian (LQG) optimal control. In addition, the Multistep Multivariable Adaptive Regulator (MUSMAR) control algorithm that adjusts its gains to every plant dynamic change, including parameters, is tested. Although the mentioned control concepts are applied considering the flow as the only manipulated variable, the combination of the latter with the radiation flux reflected by the heliostat field is also studied through PI control. The solar tower electrical power production has a maximum for a given outlet temperature that changes with plant parameters and disturbances. The improvement of production levels is conducted by adjusting the temperature reference with a static optimization procedure.As torres solares são sistemas de produção de energia elétrica que utilizam a radiação solar concentrada como fonte primária. A última, é absorvida por um fluído que percorre o permutador de calor em que a radiação incide. A presente dissertação estuda a aplicação de várias estratégias de controlo com o objetivo de manter a temperatura do fluido no valor que maximiza a produção de energia. As dificuldades principais centram-se na não linearidade da dinâmica da temperatura do fluído, nos limites térmicos do sistema e na incapacidade de manipular a radiação solar. A alteração da dinâmica da temperatura com o caudal requer a utilização de um controlador de parâmetros variáveis que resulta de um esquema de escalonamento de ganhos ou da associação de diversos controladores projetados para diferentes pontos de operação. O primeiro método é desenvolvido com controlo PI enquanto que o último recorre ao controlo LQG. Em adição, é estudada a aplicação do algoritmo de controlo MUSMAR, em que os ganhos são adaptados para qualquer alteração da dinâmica do sistema, incluindo a variação de parâmetros do modelo. Embora as estratégias de controlo referidas considerem apenas o caudal como variável manipulável, a combinação da última com o fluxo de radiação é tambem estudada com um controlador PI. A produção de energia de uma torre solar possui um máximo para uma dada temperatura que se altera com os parâmetros da planta e perturbações. O aumento da produção é conseguida pela determinação da referência de temperatura através de um algoritmo de otimização estática.N/

Robust Controller for Delays and Packet Dropout Avoidance in Solar-Power Wireless Network

Solar Wireless Networked Control Systems (SWNCS) are a style of distributed control systems where sensors, actuators, and controllers are interconnected via a wireless communication network. This system setup has the benefit of low cost, flexibility, low weight, no wiring and simplicity of system diagnoses and maintenance. However, it also unavoidably calls some wireless network time delays and packet dropout into the design procedure. Solar lighting system offers a clean environment, therefore able to continue for a long period. SWNCS also offers multi Service infrastructure solution for both developed and undeveloped countries. The system provides wireless controller lighting, wireless communications network (WI-FI/WIMAX), CCTV surveillance, and wireless sensor for weather measurement which are all powered by solar energy

Low-Cost Inventions and Patents

Inventions have led to the technological advances of mankind. There are inventions of all kinds, some of which have lasted hundreds of years or even longer. Low-cost technologies are expected to be easy to build, have little or no energy consumption, and be easy to maintain and operate. The use of sustainable technologies is essential in order to move towards a greater global coverage of technology, and therefore to improve human quality of life. Low-cost products always respond to a specific need, even if no in-depth analysis of the situation or possible solutions has been carried out. It is a consensus in all industrialized countries that patents have a decisive influence on the organization of the economy, as they are a key element in promoting technological innovation. Patents must aim to promote the technological development of countries, starting from their industrial situations

Design Optimization of Wind Energy Conversion Systems with Applications

Modern and larger horizontal-axis wind turbines with power capacity reaching 15 MW and rotors of more than 235-meter diameter are under continuous development for the merit of minimizing the unit cost of energy production (total annual cost/annual energy produced). Such valuable advances in this competitive source of clean energy have made numerous research contributions in developing wind industry technologies worldwide. This book provides important information on the optimum design of wind energy conversion systems (WECS) with a comprehensive and self-contained handling of design fundamentals of wind turbines. Section I deals with optimal production of energy, multi-disciplinary optimization of wind turbines, aerodynamic and structural dynamic optimization and aeroelasticity of the rotating blades. Section II considers operational monitoring, reliability and optimal control of wind turbine components

Design Optimization of Wind Energy Conversion Systems with Applications

Modern and larger horizontal-axis wind turbines with power capacity reaching 15 MW and rotors of more than 235-meter diameter are under continuous development for the merit of minimizing the unit cost of energy production (total annual cost/annual energy produced). Such valuable advances in this competitive source of clean energy have made numerous research contributions in developing wind industry technologies worldwide. This book provides important information on the optimum design of wind energy conversion systems (WECS) with a comprehensive and self-contained handling of design fundamentals of wind turbines. Section I deals with optimal production of energy, multi-disciplinary optimization of wind turbines, aerodynamic and structural dynamic optimization and aeroelasticity of the rotating blades. Section II considers operational monitoring, reliability and optimal control of wind turbine components

Symmetry in Renewable Energy and Power Systems

This book includes original research papers related to renewable energy and power systems in which theoretical or practical issues of symmetry are considered. The book includes contributions on voltage stability analysis in DC networks, optimal dispatch of islanded microgrid systems, reactive power compensation, direct power compensation, optimal location and sizing of photovoltaic sources in DC networks, layout of parabolic trough solar collectors, topologic analysis of high-voltage transmission grids, geometric algebra and power systems, filter design for harmonic current compensation. The contributions included in this book describe the state of the art in this field and shed light on the possibilities that the study of symmetry has in power grids and renewable energy systems

Design of Flight Control Laws for a Novel Stratospheric Dual-Aircraft Platform

Dual-aircraft platform (DAP) is a novel concept that features two glider-like unmanned aerial systems (UAS) tethered via a thin adjustable cable allowing them to sail back-and-forth, without propulsion, using vertical wind shear. DAP offers the potential of a low-cost atmospheric satellite. This thesis presents the results of an initiative to demonstrate this novel flight concept through modeling, simulation, and flight testing at Embry-Riddle Aeronautical University (ERAU). A realistic simulation environment, described herein, was developed to support the development and testing of flight control systems. This environment includes nonlinear aerodynamic models for the aircraft, a multi-element cable dynamics model, propeller-motor thrust model, control surface actuator models, and permits time-varying wind profiles. This simulator offers both pilot-in-the-loop control and autonomous sailing flight control, and X-Plane interface to provide visualization cues. An intensive flight test program, described herein, was conducted to support the validation of the DAP concept. MAXA Pro 4m gliders were assembled, instrumented, and flight tested in an effort to physically demonstrate the sailing mode of flight. The flight test program described here focuses on the capability to sail with one aircraft (i.e., fly without propulsion) while towing (i.e., pulling) a moving truck as an intermediate step towards the more complex scenario of sailing with two connected aircraft. Two vital elements of the flight software are implemented and analyzed herein. The accuracy of wind estimation techniques is evaluated using flight testing. The robustness of an L1 adaptive controller is evaluated within the flight simulation environment by comparing its performance with a conventional controller

Acoustic and Elastic Waves: Recent Trends in Science and Engineering

The present Special Issue intends to explore new directions in the field of acoustics and ultrasonics. The interest includes, but is not limited to, the use of acoustic technology for condition monitoring of materials and structures. Topics of interest (among others): • Acoustic emission in materials and structures (without material limitation) • Innovative cases of ultrasonic inspection • Wave dispersion and waveguides • Monitoring of innovative materials • Seismic waves • Vibrations, damping and noise control • Combination of mechanical wave techniques with other types for structural health monitoring purposes. Experimental and numerical studies are welcome