An Adaptive Droop Scheme for Improving Transient and Steady-State Power Sharing Among Distributed Generators in Islanded Microgrids

The droop control laws lack proportional power sharing in transient as well as steady-state conditions in AC microgrids. This paper proposes an adaptive droop coefficients based control strategy to address this issue. The droop coefficients are adaptively changed based on the output currents of the distributed generators. An appreciable improvement is achieved in the power sharing by using adaptive droop coefficients instead of fixed coefficients values. The proposed strategy can be used with conventional as well as inverse droop control laws in AC microgrids to enhance their performance. The proposed method does not require any type of additional communication or any extra hardware for its operation. The proposed scheme has been validated using extensive simulations and experiments for conventional and inverse droop laws using different type of loads (constant power, unbalanced, non-linear, dynamic). Further, the small signal eigenvalue analyses is used to find the stability limit of the variables used in the proposed scheme.