Battery State of Charge Management by Voltage Feedback Modification

Due to increase in utilization of DC loads and renewable resources which mostly produce DC powers, there has been an increasing popularity in DC microgrids. In the previous research studies, the focus is more on power balancing among parallel voltage sources of the system while balancing the State of Charge (SoC) of batteries has been overlooked. In this paper, by modifying droop control method as the basis of power sharing in the DC microgrid, the objective of SoC equalization can be achieved. DC bus voltage scheduling is the core of modification to keep the batteries SoCs balanced. First, the paper discusses about an existing droop control based SoC balancing method with voltage scheduling. Then, it proposes a new DC bus voltage scheduling to overcome the drawback of the mentioned method. The methods have been simulated in MATLAB/Simulink and a comparison study has been performed.