Robust Power System Stabilizer Modeling and Controller Synthesis Framework

This study investigates uncertain power system modeling and controller synthesis frameworks for both unstructured and structured uncertainty cases by considering the single machine infinite bus power systems that substantiates the rotor oscillations of the synchronous generator at the generation end. Although the power system is highly uncertain based on the operational characteristics, the corresponding dynamics is modeled as a set of linear time-invariant systems by considering different operating points in two different uncertainty treatments, i.e., unstructured and structured uncertainty cases for global or parametric uncertainties. The corresponding uncertain power plant model is utilized to synthesize two robust controllers not only to stabilize the nominal linear time-invariant system but also to improve steady state and transient responses of the uncertain power system dynamics in the same convex hull. The multiplicative uncertainty description with a bounded uncertainty component has been chosen to reflect the power system dynamical variations in the robust modeling framework. The robust controller synthesis utilized the corresponding linear fractional transformation representation to achieve the robust performance of the uncertain power system in terms of perfect tracking to a zero reference, i.e., perfect disturbance rejections under the norm bounded uncertainty. The uncertain power system numerical modeling and two controller synthesis results for structured and unstructured uncertainty cases verify the validity of the proposed framework to reduce the magnitude and duration of the single machine infinite bus power system oscillations under dynamical variations.