Barmak Baigzadehnoe

One of the most important control layers in microgrids is the secondary control layer. This layer is responsible for compensating voltage and frequency deviations and sharing active and reactive power in the microgrid. Control strategies are commonly classified into three categories: centralized, decentralized, and distributed. The existence of a communication infrastructure for exchanging information in centralized and distributed control strategies can be a vulnerability for cyber attacks on the network, which is one of the drawbacks of these two methods. The lack of a communication infrastructure in the decentralized control structure, which compensates for voltage and frequency deviations and thereby eliminates one of the network's weaknesses against cyber attacks, has made this structure advantageous. In this research, an optimized decentralized controller based on fuzzy logic is proposed for frequency recovery and active power sharing in a microgrid. The proposed optimized fuzzy logic-based controller is independent of the need for a communication infrastructure for information exchange, which is the main goal of this research. The design of this controller is based on a quadratic-linear cost function, and an optimal solution for it is provided using the LQR (Linear Quadratic Regulator) method. The weighting coefficients Q and R in the proposed controller are determined based on fuzzy logic, which ensures the selection of the best weighting coefficients and, consequently, better performance of the controller. Only a low-pass filter dynamics is used in the control loop to design this controller. This process does not require time-dependent protocols and is event-based. By employing this method, the microgrid frequency quickly returns to its nominal value after disturbances, thus achieving the secondary control objectives (frequency recovery and active power sharing) effectively.