Discrete consensus-based distributed secondary control scheme with considering time-delays for DC microgrid

Abstract

To ensure stable and optimal operation of DC microgrid, a three-level based hierarchical control strategy is proposed which consists of primary, secondary and tertiary controls. Usually, the primary control is performed locally without communication, the higher levels, however, can be either centralized or distributed. Considering the risks brought by centralized control, such as surviving central node or link failures, this paper proposes a distributed secondary control strategy for DC microgrid which is designed by Discrete Average Consensus Algorithm (DACA). In this paper, the controller embedded the distributed strategy will communicate with their neighbors through Low Bandwidth Communication to obtain average voltage of the whole system or power flow of grid-connected converter. Through the proposed novel strategy, the secondary control objectives such as reference power control, equal load sharing, voltage regulation will be realized in distributed means. Furthermore, the influence of communication delay to the strategy is studied at length, and the effectiveness and robustness of the proposed strategy are verified through detailed simulations.