Compromised Controller Design for Current Sharing and Voltage Regulation in DC Microgrid

Since a DC micro-grid consists of power converters connected through different line impedances, tuning of the voltage controller provides a simple and intuitive tradeoff between the conflicting goals of voltage regulation and current sharing. A highly flexible distributed control strategy is proposed to achieve the balanced control between the two control objectives, which includes the containment-based voltage controller and consensus-based current controller. The terminal voltage can be bounded within a prescriptive range which means each terminal voltage is controllable instead of only controlling the average voltage; meanwhile, the current-sharing performance can be regulated among converters. The two objectives, including either bounding voltages tightly or decreasing current sharing errors, can be compromised between each other by tuning the weightings of controllers. The large-signal model is developed to analyze the tuning principle about different control parameters. The proposed strategy can provide flexible control performance according to various control requirements. Experimental results and comparisons are illustrated to verify the effectiveness of the proposed method and compromised tuning under resistive loads and constant power loads, dynamic voltage boundary conditions.