Modeling And Control Of Distributed Sources Based On Multilevel Dynamic Voltage Restorer

Résumé: The main objective of this thesis is to control grid-tied SOFC/PV system taking into count power quality issue. In order to reach this goal, in addition to using multilevel converters, the previous distributed system was augmented by a dynamic voltage restorer (DVR) inserted in series between the grid and sensitive load. This work started with an overview of the power quality and its impact on the entire system from the transmission to distribution, in which the voltage sags and swells were categorized as the widest power quality problems. In this context, the DVR was presented as one of the effective solutions to deal with this kind of concern. In order to achieve adequate voltage compensation, the modeling, sizing, and control of a three-level DVR was carefully detailed in the first part of this work. In its second part, the SOFC was used to serve the dual purpose of injecting power in the grid as well as supporting the DVR, which avoids the need for an extra energy source. The same idea was then considered in the third part, where the SOFC was replaced by a PV/battery hybrid system. In this case, the battery role is supporting the photovoltaic system when its generated power is less than the power required by the load during the sag/swell grid fault occurrence. Finally, in the aim to enhance the performance of the DVR based distributed generation systems, the traditional controllers were substituted by fuzzy logic controllers in the fourth part of this research work.

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