Adaptive Virtual Impedance‐Based Volt‐Var Control in Standalone AC Microgrids: An Overview

In inductive microgrids, there is no guarantee for installing distributed generation units at regular intervals. Consequently, impedance mismatch and reactive power sharing errors are inevitable. The virtual impedance adaptive droop control method identifies impedance mismatches as disturbances and compensates for impedance imbalance by calculating a nonphysical compensating‐impedance value, thereby achieving ideal reactive power sharing according to prevailing conditions. This control approach can be implemented in both centralized and decentralized patterns according to network capacity utilization. From an architectural perspective, the decentralized structure can be classified into two types: fully decentralized control and pseudodecentralized control. Certainly, independence from communication infrastructures is an important factor for validating the comparison of these two structures. This paper attempts to review adaptive virtual impedance droop control by comparing the differences, similarities, and approaches of these two infrastructures. Finally, this paper mainly investigates the impact of small‐signal analysis on AVI control in fully decentralized and pseudodecentralized structures, and the findings are presented accordingly.