In the island operation of low-voltage micro-grid

the parallel control of inverter based on the droop control strategy will cause such problems as power coupling

difficult distribution of output power and system loop current due to the difference of controller parameters and line impedance. In this paper

a kind of improved sag control strategy by way of introducing virtual impedance is proposed. The negative resistive part of the virtual impedance is introduced to reduce the resistive component of the line

and the inductive part of the virtual impedance increases the inductive component of the system

weakens the degree of power coupling and improves the power distribution accuracy and loop suppression effect. The voltage feedback and voltage compensation in the reactive power droop control is introduced to increase the output voltage of the inverter

reducethevoltagedropandkeeptheparalleloperationoftheinverterhaveagoodpowersupply quality.The effectiveness of the improved control method in the paper is verified by Matlab/Simulink simulation.