Modeling and robust control of autonomous hybrid power systems

摘要

This thesis summarises a study on dynamic assessment of autonomous hybrid power systems, with the emphasis on wind-diesel systems. The main subjects are modeling, control and dynamic system analysis. The Norwegian wind-diesel prototype system is used as basis for the controller design. A comprehensive theoretical study on model based robust control of this system is performed, and some of the results are verified through experiments. Dynamic models of the main components of wind-diesel system are presented. The main objective of the modeling work has been to develop component models at an equal level of complexity, and which are appropriate for controller design and stability analysis. The models should also be able to predict power quality in terms of grid voltage and frequency variations. A main challenge has been to select models that are suitable for analysis of relatively small autonomous power systems. The main contribution of the modeling work is the assembly of component models into a flexible simulation tool that enables analysis of various wind-diesel system configurations. An important basis for the modular framework is the novel approach to structuring of the steady state electrical model equations. The model framework is flexible, and can easily be extended to represent a general electrical network topology, and to include other renewable energy sources. Analyses of the plant model did not reveal particular difficulties with respect to controller design. The main eigenfrequency and resonant peak at around 3 Hz, was identified as a main bandwidth limitation. (ERA citation 19:032968)