Catégorie : 2024

Tarek Ahmed-Ali

LINEACT-CESI, ENSICAEN

vendredi 20 septembre 2024, 10h
Salle des commissions
Campus Saint-Jérôme

Adaptive observers: From finite to infinite dimensional systems

Abstract:
This talk is devoted to adaptive observers for some classes of distributed parameters systems. We will show that several existing results for finite dimensional systems can be extended to infinite dimensional systems More precisely, new finite-dimensional adaptive observers are proposed for uncertain heat equation and a class of linear Kuramoto-Sivashinsky equation (KSE) with local output. The observers are based on the modal decomposition approach and use a classical persistent excitation condition to ensure prac tical exponential convergence of both states and parameters estimation. An important challenge of this work is that it treats the case when the function φ1(·,t) of the unknown part in the PDE model, depends on the spatial variable and φ1(·,t) ∈ L2(0,1) .

Pere Colet and Damia Gomila

Instituto de Física Interdisciplinar y Sistemas Complejos, IFISC (CSIC-UIB)

11 juillet 2024, 14h
Salle des commissions
Campus Saint-Jérôme
https://univ-amu-fr.zoom.us/j/88505334444?pwd=38rJZyBA8Df7TDvy1nCra7u0QstRaV.1

Pere Colet
Power grid frequency fluctuations in scenarios of large penetration of renewables


As the transition towards a sustainable energy system accelerates, conventional power plants are progressively replaced by variable renewable energy sources. This reduces the overall flexibility of the grid, requiring additional control strategies to ensure stable operation. We consider a model for the high-voltage grid including conventional and variable renewable generation, as well as demand variations. By assimilating load and generation data, the model reproduces frequency fluctuations with the current power mix with a high degree of accuracy. Moreover, it allows to simulate the frequency dynamics for different scenarios with a very high penetration of renewable energy. As a case study, we analyze the power grid of Gran Canaria, which is isolated, and the Balearic Islands, connected to mainland with a DC cable, considering an increasing share of, respectively wind and solar generation.

Damia Gomila
Power grid frequency fluctuations and smart devices with dynamic demand control

The increase of electric demand and the progressive integration of renewable sources threatens the stability of the power grid. To solve this issue, several methods have been proposed to control the demand side instead of increasing the spinning reserve in the supply side. Here we focus on dynamic demand control (DDC), a method in which smart devices can autonomously delay its scheduled operation if the electric frequency is outside a suitable range. DDC can effectively reduce small and medium size frequency fluctuations but, due to the need of recovering pending tasks, the probability of large demand peaks, and hence large frequency fluctuations, may actually increase. Although these events are very rare they can potentially trigger a failure of the system and therefore strategies to avoid them have to be addressed. We show also that an improved method including communication among DDC devices belonging to a given group, such that they can coordinate opposite actions to keep the group demand more stable can reduce the amount of pending tasks by a factor 10 while large frequency fluctuations are significantly reduced or even completely avoided.