A fuzzy adaptive fractional order-PID controller for frequency control of an islanded microgrid under stochastic wind/solar uncertainties

Abstract

Frequency control is the key factor in a renewable energy-based microgrid system. The inherent dynamics and low inertia of most power generating units of microgrids lead to frequency oscillations in the system. This manuscript well addresses on a robust fuzzy adaptive Fractional Order-PID (fuzzy FO-PID) controller and this is used in an AC microgrid model for achieving frequency control under various disturbances. Since a microgrid is devised with a lot of low inertia and large dynamics-based power-generating units, conventional controllers are found to be inferior while controlling the frequency of a microgrid. In the light of this, this work employs a robust fuzzy adaptive Fractional Order-PID controller to achieve improved frequency performance in the microgrid. The proposed fuzzy FO-PID controller acts as a secondary frequency control loop to amend necessary control actions over vibrant frequency under different uncertainties like load dynamics, wind fluctuation and solar intensity variation. The proposed controller is governed by a novel teaching–learning-based optimization (TLBO) technique to obtain optimal parameters under various disturbances. An assignment on a comparative study has been synthesised to justify the supremacy of the proposed TLBO algorithm in regard to the frequency control of a microgrid system.