COMMANDE DIRECTE ET OBSERVATION DES CONVERTISSEURS DE PUISSANCE : APPLICATION À I'ONDULEUR DE TENSION TRIPHASE
This dissertation deals with the control and observation of the voltage source inverter. It is divided into 4 main parts. The first one concerns the modeling of the power converter, and its classical représentation into différent coordinates is shown in détail. At the same time, we présent in détail the différent applications which we are interested in: the reactive power compensation and the active filtering. The second part treats the study of a direct sliding mode controUer based on the minimal simplex. This approach allows to overcome some ambiguity problems arisen in the task of selecting the inverter's switches signais. Comparisons with the classical hystérésis controUer are made in order to highlight the main properties of the proposed approach. In the third part of this dissertation we propose an approach, based on the previous one, which allows to fixe the switching frequency of the converter. Moreover, this previous resuit was enhanced by adding a compensation technique of the delays induced by the measurement process. Some expérimental results showed the validity of the analysis and simulations. The last part of this work deals with the design of two kinds of nonlinear observers (a Kalman-type observer and a sliding mode observer). When applied to the power inverter, the observers offer us the possibility of reducing the number of sensors or even of using this soft sensor as redundant for security purposes. Two cases are treated in détail: an observer for the DC-link voltage from the measurements of the currents of the main and another one which allows to observe the currents of the main from the DC-link voltage's measurement.