Autonomous control of distributed generation and storage to coordinate P/Q sharing in islanded microgrids - An approach beyond droop control

In this paper, a decentralized control for coordinate both active and reactive powers is proposed for islanded microgrids. Compared with the conventional droop control strategies, the proposed control realizes decentralized power distribution among renewable energy sources (RES) and energy storage systems (ESS) according to the local source conditions. Based on bus-signaling method, the ESS is able to limit charging power by decreasing RES power generation automatically. As well, the reactive power coordinated control makes the RES units able to support reactive power in a decentralized way, which allows ESS providing for more active power availability. Moreover, the reactive power is distributed according to the apparent power capacity of each unit. The control strategy principle is simple and easy to implement without extra communication requirements. Real time hardware-in-the-loop results are presented to show the feasibility of proposed control strategy.