Coordinated control method of multiple hybrid energy storage systems based on distributed event-triggered mechanism

摘要

An islanded DC microgrid with multiple hybrid energy storage systems is the object of this research, and a hierarchical coordinated control method of hybrid energy storage systems based on an event-triggered mechanism is proposed. The local layer adopts a virtual-resistance droop control and conducts the power distribution of a battery and a supercapacitor using a low-pass filter. Control strategies based on the state of charge are proposed to achieve coordinated and safe operation between hybrid energy storage systems. The distributed control layer uses a sparse communication network to regulate the average voltage and the proportional current of each hybrid energy storage system to improve the problems arising from a large bus voltage deviation and poor power sharing accuracy caused by virtual and line resistances. Based on this research, a Zeno-free event-triggered control method is proposed. The detailed derivation and proof process of the method is introduced using Lyapunov stability theory. This method can achieve similar control performance as time-triggered, but with fewer communication traffic. By setting prejudgment thresholds of the triggering function, the communication traffic is further reduced during the steady state of the system. Finally, simulations studies are conducted to demonstrate the effectiveness and robustness of the proposed control method in an islanded DC microgrid.