Improved Droop Control Strategy for Reactive Power Sharing of Parallel Inverters In Low-Voltage Microgrid

Abstract

In this paper, the mechanism of power sharing of parallel inverters in low-voltage microgrid is analyzed. It is determined the reasons that traditional droop control cannot realize reactive power sharing are the power coupling and feeder impedance mismatching, although it can realize real power sharing well. In order to solve those problems, an improved droop control strategy is studied in this paper. Firstly, the equivalent feeder impedance is designed to be inductive based on virtual impedance to decouple power. Moreover, the adaptive part of virtual impedance is introduced and adjusted by reactive power, so that the output voltage differences caused by impedance differences can be compensated without detecting feeder impedance parameters. Then the accuracy of reactive power sharing can be further improved. Finally, the validity of the improved droop control strategy was verified on the Matlab/Simulink simulation platform.