Abstract:In the island mode, The conventional droop control method of frequency/active power, voltage/reactive power is adopted when the equivalent output impedance of the inverter is designed to approximate the precondition of sensibility. However, due to the output reactive power is related to the impedance of the line, and the positions of the inverters are dispersed to make the impedance of the connection line different, it is difficult to achieve a reasonable distribution of reactive power. In this paper, the traditional droop control principle is analyzed, and the equivalent output impedance of the inverter is designed to be approximated inductive by the virtual reactance method. Thus, an improved droop control strategy is adopted to solve it. This strategy roughly compensates for the voltage drop on the line impedance difference by adjusting the reference voltage in the droop control. At the same time, a dynamic droop coefficient is used in place of the traditional fixed droop coefficient to dynamically adjust the output reactive power, Thus, the distribution accuracy of reactive power output of microgrid can be improved and the system circulation can be suppressed. Finally, a parallel operation model of two inverters is built by MATLAB/Simulink, and the feasibility of the improved control strategy is verified by comparing traditional droop control with improved droop control.