Controlo preditivo distribuído em edifícios para conforto térmico e alocação de cargas

Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica Ramo de Automação e Electrónica Industrial

Controlo preditivo distribuído para conforto térmico em edifícios

Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica Ramo de Automação e Electrónica Industrial

Vilancicos portugueses do século XIV ao XVIII

A primeira intenção deste artigo é avivar o conhecimento do vilancico, género poético-musical que permaneceu, durante quase dois séculos, no esquecimento da História da Música nacional. Canção genuinamente peninsular, o vilancico português foi mesmo o género mais profusamente conhecido e executado em Portugal, nos séculos XV ao XVIII, e que teve enorme aceitação na Igreja, na corte, na nobreza e no povo. Apesar de pouco conhecido, o vilancico, que começou popular e profano, assumiu-se depois sacro- profano ao entrar nos templos e acabou por ser religioso e imprescindível nos serviços litúrgicos do Ofício e da Missa. Foi motivação para que as igrejas se enchessem de devotos, que procuravam nele o fortalecimento da Fé; de não devotos, que corriam aos templos para os ouvir e ver a espectacularidade com que eram cantados e representados. Esteve presente nos serões e festas comemorativas dos palácios da corte e dos fidalgos. Os dramaturgos, de então, deram-lhe grande relevo ao inclui-lo nas suas peças teatrais. É justo, por isso, que se dê ao vilancico a atenção que merece para que, cada vez mais, seja conhecido e executado. Este é o principal objectivo deste artigo.

Distributed MPC for Thermal Comfort and Load Allocation with Energy Auction

This paper presents a distributed predictive control methodology for indoor thermal comfort that optimizes the consumption of a limited shared energy resource using an integrated demand-side management approach that involves a power price auction and an appliance loads allocation scheme. The control objective for each subsystem (house or building) aims to minimize the energy cost while maintaining the indoor temperature inside comfort limits. In a distributed coordinated multi-agent ecosystem, each house or building control agent achieves its objectives while sharing, among them, the available energy through the introduction of particular coupling constraints in their underlying optimization problem. Coordination is maintained by a daily green energy auction bring in a demand-side management approach. Also the implemented distributed MPC algorithm is described and validated with simulation studies.

Fuzzy, integer and fractional-order control: Application on a wind turbine benchmark model

This paper presents a comparison between proportional integral control approaches for variable speed wind turbines. Integer and fractional-order controllers are designed using linearized wind turbine model whilst fuzzy controller also takes into account system nonlinearities. These controllers operate in the full load region and the main objective is to extract maximum power from the wind turbine while ensuring the performance and reliability required to be integrated into an electric grid. The main contribution focuses on the use of fractional-order proportional integral (FOPI) controller which benefits from the introduction of one more tuning parameter, the integral fractional-order, taking advantage over integer order proportional integral (PI) controller. A comparison between proposed control approaches for the variable speed wind turbines is presented using a wind turbine benchmark model in the Matlab/Simulink environment. Results show that FOPI has improved system performance when compared with classical PI and fuzzy PI controller outperforms the integer and fractional-order control due to its capability to deal with system nonlinearities and uncertainties. © 2014 IEEE.

Modeling for control design of a multi-reach water canal

This article addresses the problem of obtaining reduced complexity models of multi-reach water delivery canals that are suitable for robust and linear parameter varying (LPV) control design. In the first stage, by applying a method known from the literature, a finite dimensional rational transfer function of a priori defined order is obtained for each canal reach by linearizing the Saint-Venant equations. Then, by using block diagrams algebra, these different models are combined with linearized gate models in order to obtain the overall canal model. In what concerns the control design objectives, this approach has the advantages of providing a model with prescribed order and to quantify the high frequency uncertainty due to model approximation. A case study with a 3-reach canal is presented, and the resulting model is compared with experimental data. © 2014 IEEE.

Fractional order control on a wind turbine benchmark

This paper is about a hierarchical structure with an event-based supervisor in a higher level and a fractional-order proportional integral (FOPI) in a lower level applied to a wind turbine. The event-based supervisor analyzes the operation conditions to determine the state of the wind turbine. This controller operate in the full load region and the main objective is to capture maximum power generation while ensuring the performance and reliability required for a wind turbine to be integrated into an electric grid. The main contribution focus on the use of fractional-order proportional integral controller which benefits from the introduction of one more tuning parameter, the integral fractional-order, taking advantage over integer order proportional integral (PI) controller. Comparisons between fractional-order pitch control and a default proportional integral pitch controller applied to a wind turbine benchmark are given and simulation results by Matlab/Simulink are shown in order to prove the effectiveness of the proposed approach.

Constituição Anotada da República Democrática de Timor-Leste

A independência de Timor-Leste, proclamada pela Frente Revolucionária do Timor-Leste Independente (FRETILIN) em 28 de novembro de 1975, vê-se internacionalmente reconhecida a 20 de maio de 2002, uma vez concretizada a libertação do povo timorense da colonização e da ocupação ilegal da Pátria Maubere por potências estrangeiras. A elaboração e adoção da Constituição da República Democrática de Timor- -Leste culminam a secular resistência do povo timorense, intensificada com a invasão de 7 de dezembro de 1975. A luta travada contra o inimigo, inicialmente sob a liderança da FRETILIN, deu lugar a formas mais abrangentes de participação política, com a criação sucessiva do Conselho Nacional de Resistência Maubere (CNRM), em 1987, e do Conselho Nacional de Resistência Timorense (CNRT), em 1998. A Resistência desdobrou-se em três frentes. A frente armada foi protagonizada pelas gloriosas Forças Armadas de Libertação Nacional de Timor-Leste (FALINTIL), cuja gesta histórica cabe exaltar. A ação da frente clandestina, astutamente desencadeada em território hostil, envolveu o sacrifício de milhares de vidas de mulheres e homens, em especial jovens, que lutaram com abnegação em prol da liberdade e independência. A frente diplomática, conjugadamente desenvolvida em todo o Mundo, permitiu abrir caminho para a libertação definitiva. Na sua vertente cultural e humana, a Igreja Católica em Timor-Leste sempre soube assumir com dignidade o sofrimento de todo o Povo, colocando-se ao seu lado na defesa dos seus mais elementares direitos. Esta Constituição representa, finalmente, uma sentida homenagem a todos os mártires da Pátria. Assim, os Deputados da Assembleia Constituinte, legítimos representantes do Povo eleitos a 30 de agosto de 2001; Alicerçados ainda no ato referendário de 30 de agosto de 1999, que, concretizado sob os auspícios da Organização das Nações Unidas, confirmou a vontade autodeterminada de independência; Plenamente conscientes da necessidade de se erigir uma cultura democrática e institucional própria de um Estado de Direito onde o respeito pela Constituição, pelas leis e pelas instituições democraticamente eleitas sejam a sua base inquestionável; Interpretando o profundo sentimento, as aspirações e a fé em Deus do povo de Timor-Leste; Reafirmam solenemente a sua determinação em combater todas as formas de tirania, opressão, dominação e segregação social, cultural ou religiosa, defender a independência nacional, respeitar e garantir os direitos humanos e os direitos fundamentais do cidadão, assegurar o princípio da separação de poderes na organização do Estado e estabelecer as regras essenciais da democracia pluralista, tendo em vista a construção de um país justo e próspero e o desenvolvimento de uma sociedade solidária e fraterna. A Assembleia Constituinte, reunida na sessão plenária de 22 de março de 2002, aprova e decreta a seguinte Constituição da República Democrática de Timor-Leste:

Fractional order control on a wind turbine benchmark

This paper is about a hierarchical structure with an event-based supervisor in a higher level and a fractional-order proportional integral (FOPI) in a lower level applied to a wind turbine. The event-based supervisor analyzes the operation conditions to determine the state of the wind turbine. This controller operate in the full load region and the main objective is to capture maximum power generation while ensuring the performance and reliability required for a wind turbine to be integrated into an electric grid. The main contribution focus on the use of fractional-order proportional integral controller which benefits from the introduction of one more tuning parameter, the integral fractional-order, taking advantage over integer order proportional integral (PI) controller. Comparisons between fractional-order pitch control and a default proportional integral pitch controller applied to a wind turbine benchmark are given and simulation results by Matlab/Simulink are shown in order to prove the effectiveness of the proposed approach.

Fuzzy, integer and fractional-order control: application on a wind turbine benchmark model

This paper presents a comparison between proportional integral control approaches for variable speed wind turbines. Integer and fractional-order controllers are designed using linearized wind turbine model whilst fuzzy controller also takes into account system nonlinearities. These controllers operate in the full load region and the main objective is to extract maximum power from the wind turbine while ensuring the performance and reliability required to be integrated into an electric grid. The main contribution focuses on the use of fractional-order proportional integral (FOPI) controller which benefits from the introduction of one more tuning parameter, the integral fractional-order, taking advantage over integer order proportional integral (PI) controller. A comparison between proposed control approaches for the variable speed wind turbines is presented using a wind turbine benchmark model in the Matlab/Simulink environment. Results show that FOPI has improved system performance when compared with classical PI and fuzzy PI controller outperforms the integer and fractional-order control due to its capability to deal with system nonlinearities and uncertainties. © 2014 IEEE.

Modeling for control design of a multi-reach water canal

This article addresses the problem of obtaining reduced complexity models of multi-reach water delivery canals that are suitable for robust and linear parameter varying (LPV) control design. In the first stage, by applying a method known from the literature, a finite dimensional rational transfer function of a priori defined order is obtained for each canal reach by linearizing the Saint-Venant equations. Then, by using block diagrams algebra, these different models are combined with linearized gate models in order to obtain the overall canal model. In what concerns the control design objectives, this approach has the advantages of providing a model with prescribed order and to quantify the high frequency uncertainty due to model approximation. A case study with a 3-reach canal is presented, and the resulting model is compared with experimental data. © 2014 IEEE.

A Batalha de Aljubarrota – Uma explicação geográfica

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Ciência e Sistemas de Informação Geográfica

Performance assessment of a wind energy conversion system using a hierarchical controller structure

This paper deals with a hierarchical structure composed by an event-based supervisor in a higher level and two distinct proportional integral (PI) controllers in a lower level. The controllers are applied to a variable speed wind energy conversion system with doubly-fed induction generator, namely, the fuzzy PI control and the fractional-order PI control. The event-based supervisor analyses the operation state of the wind energy conversion system among four possible operational states: park, start-up, generating or brake and sends the operation state to the controllers in the lower level. In start-up state, the controllers only act on electric torque while pitch angle is equal to zero. In generating state, the controllers must act on the pitch angle of the blades in order to maintain the electric power around the nominal value, thus ensuring that the safety conditions required for integration in the electric grid are met. Comparisons between fuzzy PI and fractional-order PI pitch controllers applied to a wind turbine benchmark model are given and simulation results by Matlab/Simulink are shown. From the results regarding the closed loop point of view, fuzzy PI controller allows a smoother response at the expense of larger number of variations of the pitch angle, implying frequent switches between operational states. On the other hand fractional-order PI controller allows an oscillatory response with less control effort, reducing switches between operational states. (C) 2015 Elsevier Ltd. All rights reserved.

Supervisory control of a variable speed wind turbine with doubly fed induction generator

This paper is on an onshore variable speed wind turbine with doubly fed induction generator and under supervisory control. The control architecture is equipped with an event-based supervisor for the supervision level and fuzzy proportional integral or discrete adaptive linear quadratic as proposed controllers for the execution level. The supervisory control assesses the operational state of the variable speed wind turbine and sends the state to the execution level. Controllers operation are in the full load region to extract energy at full power from the wind while ensuring safety conditions required to inject the energy into the electric grid. A comparison between the simulations of the proposed controllers with the inclusion of the supervisory control on the variable speed wind turbine benchmark model is presented to assess advantages of these controls. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

On performance of distributed model predictive control in power system frequency regulation

This paper describes the implementation of a distributed model predictive approach for automatic generation control. Performance results are discussed by comparing classical techniques (based on integral control) with model predictive control solutions (centralized and distributed) for different operational scenarios with two interconnected networks. These scenarios include variable load levels (ranging from a small to a large unbalance generated power to power consumption ratio) and simultaneously variable distance between the interconnected networks systems. For the two networks the paper also examines the impact of load variation in an island context (a network isolated from each other).