An adaptive control method for active power reference to enhance the transient stability of grid-forming inverters considering current limitation

Effective overcurrent protection control is important for grid-forming (GFM) inverters that exhibit voltage source characteristics. To avoid significant fluctuations in the active power output of GFM inverters after fault restoration, an adaptive control method for active power reference is proposed in this paper, which aims to ensure the existence of a stable equilibrium point (SEP) during grid faults. Moreover, to achieve rapid resynchronization with the grid after fault recovery, the underlying mechanism behind the exit of the current-limiting state of the inverter is further analyzed. Based on the above study, parameter design for the gain coefficient of the adaptive control method has been conducted. Theoretical analysis, experimental validation and comparison with state-of-the-art methods indicate that the proposed method exhibits wide applicability under various grid strengths and different voltage sag depths.