||In the real world, a wind turbine generator system may be affected by various uncertain factors, such as external disturbances, wear loss of the individual components, variation of critical parameters, etc., which may result in unexpected reduced performance. In this thesis, we consider control design problem if a new wind turbine generator system, which was introduced in . Based on the robust control point of view, we establish a mathematical model with structured uncertainties for the system. A robust control is then designed based on the H∞ norm minimization principle. Moreover, the problem caused by the resistance mismatch is also addressed and handled under the integral quadratic constraint framework.|
The principle design objective considered in this thesis is to ensure the maximal power tracking and maintaining a constant rotational
speed - and hence a constant frequency of the electrical power output. In case the resistance mismatch occurs, the system equations governing the power generation are transformed in such a way that the periodic time-varying terms appearing as part of the structured uncertainties in feedback interconnection with a nominal dynamics. Integral quadratic constraints are then utilized to characterized these uncertainties and an H∞ optimal controller is designed based on the resulting robust stability criterion. The simulation results shows that the H∞ optimal controller designed by this approach renders satisfactory performance.