Additional Control Based on ADP for Droop-Controlled Distributed Generator in Islanded Microgrid

Droop controls can maintain frequency and voltage stability of islanded microgrid during small disturbances and enable plug and play of distributed generators. In this work, a novel additional control is proposed to enhance transient performance of droop controls during large disturbances. The proposed additional control is designed according to approximate dynamic planning (ADP). To ensure adaptive response, a learning process is adopted to adjust the parameters of droop control iteratively. Time constrain of the learning process is set to enhance its real-time performance. Moreover, coordinated control strategy is also explored by applied well-tuned additional control to multiple distributed generators. Simulations of an islanded microgrid with sudden load plug in are carried out, whose results validate the effectiveness of the proposed additional control.