A Novel Extended Impedance-Power Droop for Accurate Active and Reactive Power Sharing in a Multi-Bus Microgrid With Complex Impedances

This paper addresses a novel and flexible control algorithm based on complex virtual impedance for improvement of power sharing in a multi-bus microgrid with complex impedance of lines. In the proposed method, first, the Extended Impedance-Power droop equations are derived. Using nonlinear droop equations, equivalent resistance and inductance of each DG unit are obtained by active and reactive power, separately. Then, an appropriate algorithm is employed to implement Impedance-Power droop to manage the virtual impedances adaptively. The proposed algorithm can optimally share both active and reactive power, even when the structure is changed without any knowledge of microgrid parameters and high-bandwidth communication links. The parameters of the proposed controller are designed based on the nominal power of inverters. Moreover, the stability margin of the system is analyzed. Finally, the feasibility of the proposed control scheme is confirmed via simulations and experiments.