Autonomous DC Voltage Control of a DC Microgrid With Multiple Slack Terminals

Autonomous DC voltage control for a DC microgrid with multiple power and slack terminals is studied in this paper. Slack terminals respond to the generation variation and load step within a DC microgrid to maintain the DC voltage. The slack terminals considered here are grid connected VSC and energy storage systems. A voltage droop based power sharing and coordination strategy among the slack terminals is proposed for power smoothing during grid-connected condition and normal operation during islanding condition. A prototype microgrid with two power and two slack terminals is established to demonstrate the excellent operation performance of the proposed control system during various operating conditions such as power variation, islanding, and grid reconnection.