SOC Equalization Control Strategy of DC Microgrid Energy Storage Unit Based on Improved Consensus Algorithm

Distributed energy storage units (DESUs) are usually used in DC microgrids to maintain the internal power balance of the microgrid, but the unbalanced state of charge (SOC) of the energy storage unit will shorten the life of DESUs. In this paper, an adaptive droop control strategy with secondary control for DC microgrids is presented. This control approach incorporates the SOC equalization technique into the droop coefficient of the energy storage device to achieve the power balance while achieving the quick balance of SOC of the DESUs. An improved proportional integral average consistency algorithm is provided for calculating the average SOC and managing the voltage to solve the problem of steady-state inaccuracy caused by communication delay in the previous consensus algorithm, while also improving the convergence speed and power distribution accuracy of the DC microgrid. Simulation results verify the effectiveness of the control strategy.