Adaptive droop control for accurate power sharing in islanded microgrid using virtual impedance

Abstract

In this paper, the relationship between real and reactive power sharing in islanded microgrid considering the complex impedance effect is analyzed. It is determined that traditional droop control has drawbacks in achieving accurate power sharing caused by the mismatched feeder line effect. In order to enhance the power sharing accuracy, an adaptive droop control using virtual impedance for islanded microgrid is proposed. The method utilizes real and reactive power mismatch, which fed to integral controllers, and then generates the virtual inductive and resistive components. Furthermore, the virtual impedance loop is added to the drooping equation to decouple real and reactive power functions. This proposed method has the advantage of enhancing the load power sharing accuracy among distributed generations (DGs) without requiring knowledge of the line impedances. This is more adaptive to complex impedance situations. The simulation results show the feasibility and correctness of the proposed strategy.