Distributed Event-Triggered Control Strategy Based on Adaptive V-I Droop Characteristic for Accurate Load Sharing in AC Microgrids

Abstract

This paper presents a new distributed event- triggered control mechanism for accurate load sharing and voltage regulation in islanded AC microgrids (MGs). The control structure is composed of two layers. The primary control level coordinates the output current of the Distributed Energy Resources (DERs) by utilizing the V-I droop control strategy. In this method, all DERs are synchronized to a common rotating reference frame. To realize proportional load sharing among the DERs, for each DER, the d and q components of the output voltage are determined in accordance to droop characteristics of the d and q axis currents. To eliminate the load sharing caused by the line voltage drops, the slope of the droop characteristic of each DER is altered by means of a distributed secondary control scheme. The secondary controller utilizes an event-triggered communication strategy, which remarkably decreases the exchanged data and saves bandwidth. Simulation results show that the proposed method favors smooth dynamic performance and efficient network utilization.