Model-Independent Observer-Based Critically Damped Terminal Voltage Stabilization for Single Machine Infinite Bus Systems via High-Order Pole-Zero Cancellation Approach

The proposed cascade-type feedback system stabilizes the terminal voltage of single machine infinite bus (SMIB) systems using two measurements: power angle and terminal voltage. The resultant control law only requires the nominal system parameters of the SMIB, and the observer removes any model dependence. This paper provides several contributions. First, the high-order pole-zero cancellation (PZC) technique constructs the observer to estimate the time derivatives of the terminal voltage and power angle measurements without any SMIB model information. Second, the high-order PZC technique enables the outer loop to estimate the desired power angle reference along the critically damped dynamics for the terminal voltage. Third, the observer-based proportional-double integral-derivative control law for the inner loop exponentially stabilizes the power angle error by reducing the closed-loop order to 2 through the high-order PZC technique. A MATLAB/Simulink implementation of the proposed cascade-type feedback system validates the effectiveness of the proposed solution.