Adjustable Gain and Reference Signal Sharing-Based Distributed Secondary Control for Voltage Restoration and Current Equalization in DC Microgrid With Time Delay

This article proposes an adjustable gain and reference signal sharing based distributed secondary control scheme for direct current microgrids (MGs) systems. First, a consensus-based reference signal sharing strategy considering communication delay is established to synchronize the reference signals of each distributed generator (DG). As long as only one DG receives the reference signal, global synchronization can be achieved, which can effectively reduce communication resources. Then, an adjustable distributed secondary control gain that accounts for communication delay is designed to improve current equalization and voltage restoration capabilities. Lastly, simulations and hardware-in-the-loop tests are both performed across diverse scenarios including load switching, plug-and-play, and scalability operations. These tests verify that the scheme can effectively enhance voltage restoration in dc MGs. Additionally, it is capable of enhancing current equalization performance in dc MGs, even when allowable communication delay is present.