Auto tuning of PID controller of a synchronous machine connected to a linear and non linear load

A proportional-integral-derivative (PID)-based power system stabilizer (PSS) is connected to the excitation system for stability enhancement of a single machine power system. In this paper, an auto-tuning of PID controller with PSS has been proposed to damp out the low frequency oscillations in the synchronous machine. Tuning the PID gains of the controller is considered as the optimization problem, and the parameters are tuned using Adaptation law. Recursive Least Square (RLS) Identifier has been used to estimate the real time parameters for tuning PID gains. The proposed PID type PSS is thoroughly investigated for fixed RLC linear load and three phase thyristor based nonlinear load with different kinds of faults. The performance of the synchronous machine such as speed deviation, load angle and rotor angle deviation were analyzed in MATLAB Simulink based environment.