Fuzzy-PID controller based sliding-mode for suppressing low frequency oscillations of the synchronous generator

A novel intelligent stabilizer is designed to address the issue of low-frequency electromechanical oscillations in a synchronous generator in this article. This stabilizer incorporates three controllers: a three-level sliding mode controller, a fuzzy logic controller, and a proportional-integral-derivative (PID) controller enhanced through genetic algorithm optimization. The discontinuous segments of the first two levels of the sliding mode controller are substituted with fuzzy-PID links, utilizing error and its rate of change to adjust stabilizer parameters. The discontinuous portion of the third level is replaced by a saturation function to constrain current within permissible limits. The advantage of this proposed controller is that it integrates the benefits of the three constituent controllers and is capable of handling a wide range of disturbances. Additionally, thanks to the fuzzy engine, which considers error variations, there is no longer a need to calculate the error derivative, which could amplify measurement noise. The proposed stabilizer is compared to available literature results. As a result, the proposed stabilizer exhibits an undershoot of -0.003, an overshoot of 0.001, a response time of 0.01s, high robustness for parameter variations ranging from 0.5 to 4 times the nominal value, and very rapid suppression of oscillations compared to other controllers.