Distributed Event-Triggered Control for Frequency Restoration and Active Power Allocation in Microgrids with Varying Communication Time Delays

In this article, the secondary frequency restoration as well as active power allocation problem in an ac microgrid (MG) system subject to bounded varying-time delays are addressed. For each distributed generator, a distributed dynamic event-triggered control law is proposed. Besides, benefiting from using dynamic event-triggered mechanisms, the communication burdens can be measurably reduced. By analyzing the resulting system through a Lyapunov function, a sufficient condition is established to ensure stability and achieve asymptotic frequency restoration and active power sharing. Based on the sufficient condition, an explicit tolerable upper bound of all time delays is obtained. The upper bound can be used for the MG system design guideline in the planning phase, which would enhance real time operating safety. Beisides, no Zeno behavior will exist. To test the proposed control method, the experiments are conducted on the real-time simulator OPAL-RT with DSP controllers. The results demonstrate the effectiveness and performance of the proposed controller.