Comparison of Robust Fuzzy Logic and Fast output sampling feedback based Power System Stabilizer for SMIB

Power system stabilizers (PSSs) are added to excitation system to enhance the damping during low frequency oscillations. This paper presents a comparison study of fuzzy logic and fast output sampling based power system stabilizer (PSS) for stability enhancement, speed deviation (Deltaomega) and acceleration (Deltaomega) of the rotor of synchronous generator of single machine power system were taken as the input to the fuzzy logic controller. These variables take significant effects on damping on damping of the generator shaft mechanical oscillations. The stabilizing signals were computed using the fuzzy membership functions depending on these variables. The simulations were tested under cetriod de-fuzzyfication methods. In fast output sampling technique, the nonlinear model of single-machine system is linearized at different operating points and a linear state space model is obtained. For this model, a common state feedback gain is obtained using LMI technique. A robust fast output sampling feedback gain which realizes output injection gain is obtained using LMI approach. This method does not require states of the system for feedback and is easily implementable. This robust fast output sampling control is applied to non-linear model of a single machine system at different operating (equilibrium) points. These simulation results are quite encouraging and satisfactory.