Control and Power Coordination for Battery Storage based DC Micro-grid

A noble DC grid current controller is proposed in this paper for a DC micro-grid. The said controller can handle any fluctuation in the PV power generation and power demand by the load without using any grid-side converter. The injected DC grid current can be regulated by directly controlling the bidirectional DC-DC converter, which is connected to the battery. The mathematical modeling of the DC-DC bidirectional converter is carried out for the purpose of designing the controller. The proposed controller has two loops; the outer loop is used to regulate the injected DC current and the inner loop for controlling the battery current. The outer loop can be designed using the transfer function of the injected DC grid current and battery current, whereas the inner control loop can be designed by considering the transfer function of battery current and the operating duty cycle. Finally, the efficacy of the proposed controller is assessed through the MATLAB/SIMULINK environment. The results show that the controller can efficiently regulate the DC grid current under fluctuations in the PV power generation and load power demand.