Distributed Secondary Control for Active Power Sharing and Frequency Regulation in Islanded Microgrids Using an Event-triggered Communication Mechanism
Authors: Lei Ding; Qing-Long Han; Xian-Ming Zhang
As a promising paradigm of power grids, a microgrid has been gaining popularity due to its strong ability of integration of renewable energy sources such as wind turbines, photovoltaic arrays and fuel cells. The large-scale penetration of such distributed energy sources makes it costly and sometimes impractical to carry out a centralized control scheme for microgrids. As a result, it is more desirable for microgrids to adopt a distributed control scheme which requires support from communication networks. While the distributed control scheme can improve the reliability, efficiency and scalability of microgrids of microgrids, it always suffers from the limitation of communication resources, probably resulting in detrimental consequences, such as degradation or even damage of control performance. Therefore, it is essential and critical to develop a new and efficient distributed control for microgrids subject to limited communication resources.
This article is concern with active power sharing and frequency regulation in an islanded microgrid under event-triggered communication. A distributed secondary control scheme with a sampled-data-based event-triggered communication mechanism is proposed to achieve active power sharing and frequency regulation in a unified framework, where neighbourhood sampled-data exchange occurs only when the predefined triggering condition is violated. Compared with traditional periodic communication mechanisms, the proposed event-triggered communication mechanism shows some prominent ability in reducing the number of communication among neighbours while guaranteeing the desired performance level of microgrids. By employing the Lyapunov–Krasovskii functional method, some sufficient conditions are derived to characterize the effects of control gains, system parameters, and sampling period on stability of microgrids. Finally, case studies on a modified IEEE 34-bus test system are conducted to evaluate the performance of the proposed distributed control scheme, showcasing its effectiveness, robustness against load changes, and plug-and-play ability.