Metodología de análisis de observabilidad para estimadores de estado en sistemas de energía eléctrica

En este trabajo, se propone una metodología de estimación de estado de dos etapas. En la primera etapa, las mediciones son procesadas por un estimador de mínimos cuadrados ponderados, en el cual se hace la verificación de los valores de las mediciones (errores de medición y errores gruesos) y se entrega su estimado actual. En la segunda etapa se recolecta la información de la estimación de estado entregada por el estimador de mínimos cuadrados ponderados para ser el estado inicial del estimador basado en la metodología del filtro de Kalman, y junto con las pseudomediciones entregar el estado a priori del sistema de potencia, el cual se presume muy cercano al estado real en la siguiente estimación de estado. El algoritmo del filtro de Kalman permite tener una idea de los posibles escenarios a los que puede verse enfrentado el sistema de potencia en un instante futuro [2]Abstract : In this job, we propose a metodology of estimation of state in two stages. In the first stage, the measurements are processed by an estimator of weighted least squares, in which we make the verification of the values of the measurements (measurements mistakes and thick mistakes) and it gives its current estimation. In the second stage, we collect the information of the first estimation of stage given by the estimator of the weighted least squares for being the beginning state of the estimator based on the metodology of the Kalman's filter, and with pseudomeasurements, deliver the state a priori of the power system, which we presume is very near to the real state in the next state estimation. Kalman's filter algorithm lets us have an idea of the possibles scenarios that we can see face-to-face in the power system in a future instant [2]Maestrí

Design and Implementation of Piecewise-Affine Observers for Nonlinear Systems

This thesis is divided into two main parts. The contribution of the first part is to design a continuous-time Piecewise-Affine (PWA) observer for a class of nonlinear systems. It is shown that the state estimation error is ultimately bounded. The bound on the state estimation error depends on the PWA approximation error. Moreover, it is shown that the state estimation error is still convergent and ultimately bounded when the output of the system is only available at sampling instants. The proof of convergence is presented in two parts: conditions dependent on the sampling time and conditions independent of the sampling time. In addition, ultimate boundedness of the state estimation error is proven in the presence of norm bounded measurement noise. It is shown that the bound on the state estimation error is dependent on the sampling time, PWA approximation error and the bound on the norm of the noise. The proposed approach for observer design leads to a convex optimization which can be solved efficiently using available software packages. The contribution of the second part is to implement the proposed PWA observer on a real setup of a wheeled mobile robot (WMR) available at the Hybrid Control Systems (HYCONS) Laboratory of Concordia University. Although some researchers have applied different types of observers to experimental applications, practical implementation of PWA observers has not been given much attention by researchers. In this thesis for the first time a PWA observer is applied to the WMR. The WMR is an example of a nonlinear system with a sampled output in the presence of measurement noise. The results of the experimental implementation validate the proposed theoretical results in the first part

Contribution au développement des techniques ensemblistes pour l'estimation de l'état et des entrées des systèmes à temps continu (application à la détection de défauts)

Cette thèse traite du problème d'observation et d'estimation des variables caractéristiques des systèmes dynamiques. Il s agit d une problématique fondamentale qui est au cœur de nombreux domaines relavant des sciences de l'ingénieur. Les travaux sont conduits dans un contexte ensembliste. Les techniques développées pour l estimation de l état et des variables d entrées ont pour objectif final le contrôle de cohérence des systèmes non linéaires à temps continu. Une première approche conjugue les relations de parité et les différentiateurs à modes glissants pour l estimation des entrées d un système non linéaire. Les domaines des entrées compatibles avec les mesures sont alors reconstruits grâce à l analyse par intervalles et aux techniques de satisfaction de contraintes. Il est montré que la relaxation des contraintes de stabilité/coopérativité pour la construction d un observateur intervalle peut se faire grâce à des changements de base déterminés de différentes manières et pouvant être variants ou invariants dans le temps. Des simulations numériques illustrent les techniques proposées. Une application à un système aéronautique est également présentée à l aide d un jeu de données réelles.This thesis deals with the problem of a dynamical system observation and the estimation of its characteristic variables; the latter point constitutes the core element in many engineering science fields. The final aim is to build a general framework for integrity control and fault detection of such systems within a bounded error context. The developments offered herein make use of parity relations, sliding mode differentiators, interval observers and constraint satisfaction problems. Input reconstruction techniques are developed for a general class of nonlinear continuous-time systems. Domains are reconstructed for the input values which are consistent with the measurements using interval analysis and constraint satisfaction techniques. It is shown that time-varying or invariant coordinate changes may relax the applicability conditions (stability/cooperativity) of the interval observer design methods. Sliding mode differentiators were also used to enhance interval observer accuracy. The proposed approaches are illustrated through computer simulations and they have been applied to aircraft servo loop control surface for robust and early detection of abnormal positions.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF