EID Compensation Based Load Frequency Control for Islanded Microgrid with Varied Distributed Energy Sources

A robust active disturbance rejection control (ADRC), based on the compensation of estimated equivalent input disturbances (EID), is designed for the islanded ac microgrid. In an islanded microgrid with renewable sources load change, wind power fluctuation, and sun irradiation power disturbance as well as dynamical perturbation, such as damping coefficient and inertia constants, can significantly influence the system frequency, and thus the microgrid's frequency control faces some new challenges. In response to these challenges, the method has a capability of rejecting the effects of parameter uncertainties and load variation, and guaranteeing high dynamic performance by means of the compensation of EID. Firstly, the state-space models of LFC system are established. Then a full-order generalized state observer (GSO) is employed in the construction of ADRC system to estimate EID. A stability condition is derived based on small-gain theory. Finally, an isolated microgrid power system model is used to conduct case studies. The simulation results show that the proposed ADRC is significant to maintain a robust performance and grid stability by minimizing the effects of various disturbances and uncertainties.