Fully Actuated Control for Synchronous Generator Excitation

Low-frequency electromechanical oscillations pose a persistent threat to the stability and transmission capacity of modern power systems. While conventional power system stabilizers based on linear control theory are widely used, their performance often degrades under varying operating conditions due to the inherent nonlinearity of synchronous generators. Advanced nonlinear control strategies, particularly feedback linearization, offer theoretical global stability but suffer from control singularities at specific operating points, such as the no-load condition where the power angle approaches zero. To address these challenges, this paper proposes a robust nonlinear power system stabilizers design framework based on the fully actuated system theory. We derive a third-order fully actuated model for the single machine infinite bus system, explicitly establishing the relationship between the excitation voltage and the jerk of the power angle. Based on this model, a nonlinear control law is synthesized to ensure the asymptotic convergence of the power angle to its equilibrium. A rigorous stability analysis is presented, characterizing the region of attraction and proving that the closed-loop system is globally asymptotically stable for all initial states excluding the singularity itself. Furthermore, we analytically demonstrate that the singularity at the no-load equilibrium is removable, ensuring that the control input remains bounded and converges to a finite steady-state value. This approach effectively integrates the rigorous stability guarantees of nonlinear control with the implementation simplicity essential for practical power system operations.