Research on power balance control method of microgrid energy storage unit

Abstract

In the isolated island operation of microgrids, affected by the different equivalent circuit impedance between distributed generators, the traditional droop control cannot evenly divide the reactive power borne by distributed generators according to the different line impedance. Therefore, firstly, the reasons affecting power sharing are analyzed, and then an improved droop control method based on traditional droop control is proposed; that is, the time change rate of voltage is used as the droop variable, and a voltage recovery mechanism is added to the reactive droop controller, in order to adjust the reciprocal of voltage to zero in the steady state, so as to stabilize the voltage. Aiming at the problem that the droop controller cannot always realize the equal distribution of reactive power, a voltage compensation link suitable for improved droop control is designed and added to eliminate the line impedance difference between distributed generators and improve the accuracy of reactive power distribution. Finally, the effectiveness and feasibility of the proposed control strategy are verified by building a “wind light storage load” microgrid simulation model on the MATLAB / Simulink platform.