Consensus-based adaptive distributed hierarchical control of battery energy storage systems in a DC microgrid

This study presents a distributed hierarchical control strategy for battery energy storage systems (BESSs) in a DC microgrid. The strategy aims to achieve state-of-charge (SOC) balancing, current sharing, and voltage restoration in diverse operating conditions. The primary control layer employs an adaptive droop control approach that dynamically adjusts the droop coefficient based on the observed average values, SOCs, and state-of-health (SOH) of the BESSs. A consensus algorithm is utilized to estimate the relevant average parameters. At the secondary control layer, an adaptive proportional consensus algorithm-based architecture regulates the voltage by including the minimization of the difference between the DC bus voltage and reference value and balancing errors for SOC, SOH, and current with the proportional consensus algorithm. The proposed strategy guarantees the restoration of the DC bus voltage, despite the presence of sudden load variations and delays occurring during transmission or self-processing delays. A stability analysis is provided to choose the optimal parameters for the proposed adaptive distributed control. Simulations in MATLAB/Simulink and hardware-in-the-loop (HIL) tests using the Typhoon HIL device evaluate the strategy's effectiveness. Overall, the proposed strategy presents promising solutions for achieving efficient operation of BESSs in a DC microgrid.