Adaptive Virtual Impedance Control Method for Accurate Reactive Power Sharing and Circulating Current Suppression in Islanded Microgrid

In a practical microgrid, a feeder impedance mismatch increases the reactive power sharing error and circulating current among distributed generation units (DGs). This paper proposes an adaptive virtual impedance control method to improve reactive power sharing accuracy and suppress the circulating current. To achieve the control objective, the virtual impedance is added to the DG output to compensate for the mismatched feeder impedance among DGs. In addition, the proposed controller maintains a good power sharing performance despite the load changes. The effectiveness of the proposed adaptive virtual impedance control method is evaluated with PLECS simulation results.