Distributed cooperative secondary control based on discrete consensus for DC microgrid
Qingzhu Wan, Shuai Zheng
Abstract
Aiming at overcoming the drawbacks of bus voltage deviation and current sharing accuracy degradation caused by conventional v-i droop control in primary control of DC microgrid, a distributed cooperative secondary control strategy is proposed in this paper. The strategy includes voltage restoration control and current sharing control. Discrete consensus is applied in the proposed method which considers the discrete nature of measurement, controller implementation, and communication. The controller on each converter exchanges data with only its neighbors on a sparse network of communication across the DC microgrid, further dynamically tracking the output voltage and current. In addition, the proposed control strategy can reduce the impact of communication noise on consensus convergence and accuracy by introducing the consistency gain function. The effectiveness of the proposed method is verified by a grid-connected DC microgrid system based on the MATLAB/Simulink.