Flexible nonlinear voltage control design for power systems

This paper presents the Direct Feedback Linearization (DFL) technique as a simple and flexible nonlinear control method in designing robust nonlinear excitation controllers for stability enhancement and voltage regulation of power systems. This technique offers considerable flexibility in designing controllers for all relevant variables. The main advantage of this technique is the possibility of selecting various control loops for a particular application problem. This is of paramount importance in control systems and power system engineering especially where all relevant variables may not be directly measured. As an example application, four different robust nonlinear excitation controllers are designed and compared to enhance voltage regulation of a power system. Simulation results carried out on a single machine infinite bus (SMIB) power system model show the enhancement of system stability and voltage regulation for different control structures regardless of the fault and changes in network parameters.