Reactive Power Sharing and Stability of Islanded Microgrid Using Centralized Secondary Control

In this paper, we propose a centralized secondary control that is based on dynamic virtual inductances. Its purpose is to achieve accurate reactive power sharing in an islanded microgrid with multiple local buses and non-identical grid-forming converters. We also establish a mathematical model for this system and examine the stability when critical control parameters are varied. The proposed control strategy has the following advantages: i) simple structure, ii) no need to identify line impedances, iii) using a low-bandwidth communication network, iv) highly robust against communication network failures, v) providing high flexibility to maintain system stability by adjusting control parameters.