In islanded microgrids

the traditional wireless active power coordinated control may lead to the state of charge (SOC) of the battery energy storage system (BESS) getting beyond the safe operation region if imbalance between power consumption and generation lasts too long. To address this issue

a distributed active power coordinated control strategy for multiple BESS and renewable energy source (RES) units considering SOC of BESS is proposed. By integrating variable-slope droop control based on instantaneous power

constant-power proportional-integral (PI) droop control based on SOC

and power droop control based on frequency bus signaling (FBS)

an autonomous wireless coordinated control for active power is achieved. In addition

not only can the strategy proposed be easily implemented on top of the conventional BESS and RES control systems without altering the inner loop structure

but also it can keep the SOC in a safe range when efficiently utilizing the power from RES. Real-time simulation results validate the effectiveness of the control strategy proposed. This work is supported by Application Technology Research and Engineering Demonstration Program of National Energy (No. NY20150301).