Current Sharing in Decentralized DC Microgrids with Frequency-Selective Impedance Control

This paper proposes a modified droop-based frequency-selective impedance control (dFSIC) algorithm for fully distributed decentralized controlled dc microgrids with current sharing between multiple interface power converters. Unfortunately, because of the extremely low output impedance of the converters under the conventional FSIC, current sharing is not satisfactory and de microgrids might be unstable. The proposed algorithm solves these problems by adapting a droop-control strategy for the FSIC. As the result, improved algorithm extends the application of the FSIC in distributed power systems providing both steady-state voltage ripples suppression and load current sharing at the FSIC frequencies. The superior performance is demonstrated in time and frequency domains by the experiments.