Un formalisme de systèmes à sauts pour la recirculation optimale des cassés dans une machine à papier

Modélisation statistique des casses de papier -- Fonctionnement d'une machine à papier -- Nature et classification des données expérimentales -- Hypothèse markovienne et validation expérimentale -- Variation des taux de transition en fonction des paramètres d'opération -- Réglage optimal de la vitesse d'opération -- Gestion optimale de la recirculation des eaux blanches et des cassés : un formalisme de systèmes à sauts Markoviens -- Gestion optimale de la recirculation des eaux blanches et des cassés : analyse des intervalles inter-incidents extensions -- Calcul approximatif des premiers temps de passage -- Loi de commande dans le cas d'un processus de casses sensible à la commande

Jump Linear Quadratic Control for Energy Management of an Isolated Microgrid

Energy security and the aging grid infrastructure in the United States are two important subjects at the crossroads between politics and technology. One proposed solution to these two issues revolves around the concept of an isolated microgrid. Isolated microgrids are becoming increasingly popular combining multiple energy generation and storage systems to diversify and secure their private energy portfolios. The work presented in this thesis applies jump linear quadratic control to the energy management of an isolated microgrid operating with solar generation, fuel cell, and battery energy storage system. A continuous finite state Markov chain is used to model the intermittent generation of the solar array. The microgrid’s energy management state-space is formulated, optimal feedback gains are calculated through a numerical algorithm, and results from an example system illustrate the validity of the proposed approach

Stochastic Distributed Control for Arbitrarily Connected Microgrid Clusters

Due to the success of single microgrids, the coming years are likely to see a transformation of the current electric power system to a multiple microgrid network. Despite its obvious promise, however, this paradigm still faces many challenges, particularly when it comes to the control and coordination of energy exchanges between subsystems. In view of that, in this paper we propose an optimal stochastic control strategy in which microgrids are modeled as stochastic hybrid dynamic systems. The optimal control is based on the jump linear theory and is used as a means to maximize energy storage and the utilization of renewable energy sources in islanded microgrid clusters. Once the gain matrices are obtained, the concept of #-suboptimality is applied to determine appropriate levels of power exchange between microgrids for any given interconnection pattern. It is shown that this approach can be efficiently applied to large-scale systems and guarantees their connective stability. Simulation results for a three microgrid cluster are provided as proof of concept

Gradient-based optimization techniques for the design of static controllers for Markov jump linear systems with unobservable modes

The paper formulates the static control problem of Markov jump linear systems, assuming that the controller does not have access to the jump variable. We derive the expression of the gradient for the cost motivated by the evaluation of 10 gradient-based optimization techniques. The numerical efficiency of these techniques is verified by using the data obtained from practical experiments. The corresponding solution is used to design a scheme to control the velocity of a real-time DC motor device subject to abrupt power failuresFAPESP (03 / 06736-7, 04 / 06947-0)CNPq (471557 / 2009-9, 304.856 / 2007-0, 304.429 / 2007-4, 306.466 / 2010-4)Fundación Carolina (Fundación Carolina - Programa "Movilidad de Professores e Investigadores Brasil-España. C.2010 "

Optimal white water and broke recirculation policies in paper mills via jump linear quadratic control

With the increasing closure of white water circuits in paper mills, breaks in the sheet of paper have become a system-wide disturbance. Upon recognizing that such breaks can be modeled as a Markov chain type of process which, when interacting with the continuous mill dynamics, yields a jump Markov model, jump linear theory is proposed as a means of constructing white water and broke recirculation strategies which minimize process variability. Reduced process variability comes at the expense of relatively large swings in white water and broke tank levels. Since the linear design does not specifically account for constraints on the state space, under the resulting control law, damaging events of tank overflows or emptiness can occur. A methodology, mainly founded on the first passage-time theory of stochastic processes, is proposed to choose the performance measure design parameters to limit process variability while maintaining sufficiently long mean times between incidents of fluid in broke and white water tanks either overflowing or reaching dangerously low levels. The heart of the tuning approach is an approximation technique for evaluating mean first passage-times of the controlled tank height processes. This technique appears to have an applicability which largely exceeds the problem area it was designed for

Controle por horizonte retrocedente de sistemas lineares com saltos markovianos e ruido aditivo

Orientadores: João Bosco Ribeiro do Val, Eduardo Fontoura CostaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: A principal contribuição deste trabalho _e propor e resolver um problema de controle de Sistemas Lineares com Saltos Markovianos (SLSM) na presença de ruído que possa existir atuando ininterruptamente sobre estes sistemas. Adotamos o método de controle por horizonte retrocedeste sob a suposição de que os estados da Cadeia de Markov não são conhecidos pelo controlador, com exceção de uma distribuição inicial, e impomos ganhos de realimentacão linear em um problema com complexidade restrita. Incorporamos ao modelo com ruído alvos dinâmicos e entradas exógenas que podem sofrer saltos, com especial interesse em aplicações em modelos macroeconômicos, sistemas robóticos, entre outros. Desenvolvemos uma formulação determinista equivalente ao problema escolástico estudado, em que condições necessárias de otimalidade são propostas e um método iterativo baseado em um procedimento variacional soluciona o problema. Como passo intermediário para a obtenção da solução do problema de rastreamento, desenvolvemos primeiramente a solução do problema de regulação, por este se tratar de um caso particular do primeiro. Algumas aplicações são apresentadas, de forma a ilustrar numericamente a teoria desenvolvidaAbstract: The main contribution of this work is to propose and solve a control problem of Markov Jump Linear Systems (MJLS) driven by noise. We adopted the receding horizon control method assuming that the Markov state chain is not known by the controller, with the exception of an initial distribution. We impose linear feedback gain structure in a problem with restricted complexity. We add to the noisy model switching targets and exogenous inputs variables, which are interesting for applications such as macroeconomic models, robotic systems and others. We develop an equivalent deterministic formulation to the stochastic problem studied where necessary conditions of optimality are proposed and an iterative method based on a variational procedure solves the problem. As an intermediate step to attain the solution to the tracking problem, we develop first the solution to the regulation problem, since this is an particular case of the former. To illustrate numerically the theory developed, some applications are presented.MestradoAutomaçãoMestre em Engenharia Elétric