Research on autonomous operation and mutual aid strategy of AC/DC hybrid microgrid cluster

Abstract

In order to address the challenge of ensuring convergence and stability in AC/DC hybrid microgrid cluster with self/mutual communication delay, this study proposes a hierarchical control strategy. By leveraging the finite-time consistency algorithm, this strategy facilitates autonomous operation of sub-microgrids and enables mutual aid and assistance within the microgrid cluster. The proposed control strategy consists of two levels: the sub-microgrid level and the microgrid cluster level. Both levels utilize primary control along with a secondary adjustment term based on improved finite-time consistency. This strategy aims to ensure frequency and voltage stability, power equalization in the sub-microgrids, and economic allocation of power in the microgrid cluster. The proposed control strategy improves the traditional finite-time consistency protocol, considers the effect of time delay on system stability. It also introduces the convergence coefficient to strike a balance between system economy and stability objectives. Through a comparison with the traditional consistency algorithm, simulation results demonstrate that the proposed control strategy enhances the robustness of the system, enables coordinated control of frequency and voltage in sub-microgrids, facilitates economic power allocation in the microgrid cluster, and achieves faster convergence speed.