Distributed Prescribed-Time Secondary Control for Islanded AC Microgrids Under Communication Delays

IoT-enabled microgrids connect distributed generators, storage units, and loads through sensor-based communication networks for real-time monitoring. Motivated by the need for fast and reliable frequency-voltage restoration in islanded AC microgrids affected by communication delays, this paper proposes a prescribed-time distributed secondary control strategy for coordinated voltage, frequency, and active power sharing to enhance the operational stability of AC microgrids. Firstly, the distributed secondary control problem is formulated with careful consideration of different communication delays. The proposed prescribed-time consensus control, designed to be independent of initial conditions, provides a precise estimation of the settling time, ensuring efficient and predictable system performance. The proposed controller is utilized the measurements of local power and frequency and information shared with neighboring distributed generators through the communications network in order to estimate the nominal operational point using in primary control stage. Second, by using the control input's past data, a state-transformation- based approach is able to manage time delays and completely reduce the negative consequences of different communication delays. Then, the prescribed-time reactive power sharing control approach is developed. Furthermore, a distributed secondary controller stability is analyzed using the Lyapunov function. Finally, the results validate efficiency of the suggested control schemes under various test scenarios.