Nowadays renewable energy is a long term solution for replacing the conventional sources of energy. The use of photovoltaic (PV) arrays and wind turbines has become very popular. Some of the big inconveniences of these alternatives are the low conversion rate of the energy and the necessity of using an energy storing system. Another drawback is the reduced transfer efficiency between the PV arrays or/and wind turbines and the consumers. The goal of this thesis is to present and compare different control strategies for systems that are powered by renewable sources of energy. The following main problems are considered: PV panel modelling, buck converter modelling, non-linear observers design, control algorithms based on maximum power point tracking (MPPT), polynomial control algorithms, stability of the system. Chapter 2 presents different photovoltaic cell models that can be further used in control loops. A graphic user interface is created for facilitating the computation of certain parameters and of the power-voltage / current-voltage characteristics of a PV panel. Chapter 3 focuses on elaborating a Takagi-Sugeno (T-S) observer which provides the estimated voltage of the PV panel. Chapter 4 compares different MPPT algorithms, as well as advanced control algorithms which makes possible to improve the performances of the control loops. A case study of a supervisory control that uses fuel cells is presented. Chapter 5 presents a distributed control system that is managed via an OPC server. A robust R-S-T polynomial controller is designed, validated in simulation and tested on a prototype. A data acquisition system stores the data sent by each of the control loops and is able to plot data in real time. The code of the developed software and some schematics used in simulations are given in the annexes.
- Directeurs de thèse : Prof. Nicolaï Christov (Université de Lille) Prof. Dumitru Popescu (Université Politehnica de Bucarest) - Coencadrant : Prof. Abdel Aïtouche (HEI, Yncréa Hauts-de-France) - Rapporteurs : Prof. Didier Maquin (Université de Lorraine) Prof. Mircea Ivanescu (Université de Craiova) - Examinatrice : Prof. Adina Florea (Université Politehnica de Bucarest)
Thesis of the team SHOC defended on 06/11/2018