Adaptable Energy Storage System Control for Microgrid Stability enhancement

This study highlights the potential benefits of flexibly utilizing a battery energy storage system (BESS) to enhance the stability of a microgrid. The goal of this paper is to propose an adaptable fast frequency regulation strategy using a BESS. This work presents a novel converter nonlinear droop control with droop gain dependent on the Phase-Locked Loop (PLL) frequency measurement. Compared with traditional linear droop control, this new adaptable nonlinear droop demonstrates additional stability margin of the controller without performance sacrifice. A fast secondary control loop works contemporaneously to help the microgrid frequency return to the nominal value with a zero steady state error. Simulation results reveal the robustness of the control under both fault induced islanding and load switching during microgrid autonomous operation.