Stability Analysis and Controller Tuning for Load Frequency Control of Time-Delayed Microgrids

Time delays are inescapable in the load frequency control (LFC) of microgrids, especially in open communication networks. This paper focuses on the stability analysis and controller tuning for the LFC scheme of microgrids with time delays. Firstly, a time-delayed model of the LFC for microgrid is constructed, in which the Padé approximation is employed to handle the time delays for eigen-analysis. Subsequently, the Routh-Hurwitz criterion is implemented to calculate the delay margin. Furthermore, the controller is tuned based on the tradeoff between the damping ratio and delay margin, thereby enabling the microgrid system to possess good damping performance and robust stability against time delay. Finally, a case study is conducted to verify the effectiveness of the proposed controllers.