State of Charge based Control Strategy for Battery Energy Storage System in DC Microgrid

In order to achieve proper bus voltage and desired power-sharing and charging/ discharging of Battery Energy Storage System (BESS) in consideration with the state of charge (SOC) of the battery, the control design is proposed. The design is mainly proposed for the bidirectional converter of BESS in a DC Microgrid (MG). The proposed controller employs the locally obtained measurements of battery voltage as a state in control design, thereby keeps aside the use of high bandwidth communication. On sudden failure of the grid, it must be compensated by other sources in the MG and continuous supply to the load is a must. Thus the reliability of the system is achieved by operating the MG employing mode switching in between three modes: power regulation mode (PRM), constant voltage (CV) mode and voltage regulation mode (VRM) implementing control scheme of BESS. Transient performance validation is done by simulating different system disturbances such as accidental grid isolation and uncertain loading conditions taking into account the line parameters in the transmission line. To show the proof of the proposed concept of the control strategy, simulation results are provided.