Distributed Adaptive Virtual Impedance Control for Power Sharing in an Islanded Microgrid.

Accurate active and reactive power sharing in islanded microgrids is a prominent challenge. The existing conventional droop control strategies for power-sharing have disadvantages like inaccurate power-sharing among distributed generators (DGs) in the case of feeder impedance mismatch, unequal ratings of the sources etc. The complexity intensifies in the case of reactive power sharing. Virtual impedance emerges as a widely adopted technique to address impedance mismatches; however, the key challenge lies in determining the optimal value for its configuration. This paper proposes an adaptive virtual output impedance-based control for proportionate sharing of powers among the parallel connected DGs in the microgrid. The proposed control method is evaluated with the information of neighbouring DGs with data integrity. The primary focus of the paper is to attain accurate reactive power sharing. A small signal stability analysis of the system is carried out to ensure its performance. Various case studies are simulated in MATLAB Simulink to validate the robustness of the proposed control strategy.