A Distributed Droop-Free Control Strategy for DC Microgrids With Single Variable Transmission

In this paper, a distributed droop-free cooperative control strategy for DC microgrids (MGs) is proposed to transmit only single variable information in order to achieve accurate voltage restoration and current sharing in DC MGs while significantly improving the dynamic performance. Compared with methods based on multivariate transmission and multi-loop control, the control strategy proposed in this paper effectively integrates the voltage and current information into a single variable and transmits it among the converters, thus reducing the communication burden of the system. Each converter uses the consensus algorithm to obtain the single-variable average value under distributed communication, and the objectives of voltage restoration and current distribution can be achieved by single-loop secondary control, which reduces the computational burden. On this basis, the droop control in the primary control is removed, which is equivalent to instantaneous compensation of the voltage drop caused by it, avoiding redundant processing of the average current and making full use of the secondary control, thus effectively improving the overall dynamic performance of the system. In addition, the effectiveness of the scheme is verified by steady-state analysis and stability analysis, while discussing various communication topologies and communication configurations of the control strategy. The proposed control scheme is evaluated by PLECS simulation, and the feasibility and superiority of the proposed control scheme are further verified by experiments.