Distributed secondary control algorithm for islanded microgrid based on event-triggered control and adaptive sliding mode observer

This study presents a distributed cooperative secondary control strategy for islanded microgrid (MG), aiming to mitigate excessive communication load and suppress disturbances that degrade system stability during islanded MG operation. To achieve this, an improved event-triggered control (ETC) design is proposed: in the secondary control of each distributed generation (DG), local state information is acquired via direct sampling, while neighboring DGs exchange state information through event-triggered communication. The secondary control of each DG directly uses real-time sampled local state information, which avoids the lag in the secondary controller’s response caused by tracking error accumulation under small disturbance conditions and improves the controller’s dynamic response performance. This approach avoids redundant communication caused by frequent local state triggering and further reduces the communication volume between DGs. On this basis, an adaptive sliding mode observer (ASMO) is introduced to accurately estimate the system disturbances. Unlike the observer under the traditional ETC framework, the observer proposed in this paper no longer requires an intermediate step, thereby improving the estimation accuracy. Furthermore, the global stability of the system is proved by constructing the Lyapunov function and excluding the Zeno behavior that may be triggered by the ETC. Finally, the effectiveness of the proposed control strategy is further verified by numerical simulation.