Distributed Coordinated Control Strategy of Multienergy Storage in DC Microgrid Based on Improved Consensus Algorithm

Abstract

To address the imbalance in the state of charge (SOC) of distributed energy storage units (DESUs) in DC microgrids (DCMGs), this article proposes an improved droop control strategy. First, the droop coefficient of the energy storage device is linked to the SOC nested power function, enabling the energy storage unit to adaptively adjust the droop coefficient according to the SOC during charging and discharging. Second, a variable acceleration factor is introduced to further accelerate the equalization speed when the SOC difference is reduced. Current sharing compensation is added to eliminate the influence of line impedance mismatch on power distribution accuracy and a bus voltage compensation strategy is employed to maintain bus voltage stability. The improved consensus algorithm is used to accelerate the convergence speed of consistency and the information of adjacent nodes is exchanged to obtain the average value of the system. The stability of the system is demonstrated through frequency domain analysis. Finally, the proposed adaptive droop control strategy is validated by numerical simulation and hardware-in-the-loop experiments, proving the effectiveness of the proposed strategy.