Improved Resistive Droop Control Strategy for Power Sharing of Low-voltage AC Microgrid

Abstract

In low-voltage AC microgrid, the different distance between distributed generation units (DGs) and common bus leads to the mismatch of feeder impedance, which results in the error of output power sharing. In order to realize the accurate power sharing and maintain the stability of the AC bus voltage, this paper proposes an improved resistive droop control strategy based on adaptive virtual impedance, which introduces dynamic dominant resistance and negative inductance to diminish the impact caused by different feeder impedance. Furthermore, a voltage compensation stage is added to maintain the bus voltage at a satisfactory value by mitigating the voltage drop caused by the virtual impedance. The effectiveness of the proposed control strategy has been demonstrated by various simulation cases. The results show that the proposed control strategy can deal with conditions of dynamic and nonlinear load without the information of accurate feeder parameters.