Hierarchical Control Strategy for Islanded Microgrids based on Event-Triggered Mechanism

Microgrids are an effective means to flexibly manage and control distributed power sources. Control of microgrids typically employs a hierarchical control framework. In primary control, traditional droop control often leads to deviations in the steady-state frequency and voltage, which usually requires secondary control to resolve. Nevertheless, the conventional secondary control relies on periodic communication, potentially leading to a substantial utilization of communication resources. To tackle these challenges, this paper proposes two main solutions. Firstly, enhancements are made to traditional droop control, enabling it to regulate frequency and voltage towards reference values established in primary control. Subsequently, an event-triggered distributed secondary control mechanism is introduced to ensure precise power distribution. Only if the measurement error exceeds a predefined threshold, the controller is updated and information is exchanged with the neighbors. When the system reaches a stable state, only minimal communication is required, thereby the communication resources is effectively saved.