A Consensus-based Adaptive Virtual Output Impedance Control Scheme for Reactive Power Sharing in Meshed Microgrids

This paper presents a distributed secondary control scheme for accurate reactive power sharing in an islanded meshed microgrid. The scheme employs consensus control to adaptively tune the virtual output impedance (VOI) into achieving power correction. The adaptive VOI-based control structure is essentially non-linear. However, this work shows that the approximate range of stable coupling gain can be established by linearizing the problem about every probable operating point of the distributed energy resources (DERs). On the basis of islanding mode, it is shown also that only the dynamic virtual output reactance component is needed while the static component, which has been used extensively to date, can be nullified. The proposed control scheme can realize an accurate power sharing among the DERs regardless of the microgrid topology, load condition, and communication delay (within the allowable limits defined by the consensus theorem). The study is carried out in conjunction with an islanded microgrid model modified from the IEEE 34 Node Test Feeder.