DC Micro-Grid with Isolated Bi-Directional Converter-Based Battery Storage System and It's Control

To meet the power requirement, a PV integrated battery storage system (BSS) is used in this work. The power requirement is met by charging and discharging the battery as needed to keep the output DC voltage consistent. A photovoltaic (PV) system with a Boost converter with Perturb & Observe (P&O) control was installed in the beginning. In next stage, an isolated DC-DC Dual Active Bridge (DAB) bidirectional converter (BDC) is being implemented to charge the battery in one mode and to use the battery as a power source to power the load using same BDC in another mode. In the later stage, Constant Current and Constant Voltage (CC-CV) have been discussed and it has been implemented for an efficient way of charging the Battery. For various load applications required constant output voltage is being properly maintained. For higher irradiance level and when the battery is fully charged the PV system cannot maintain the DC micro-grid voltage constant as the battery cannot be charged further. So to maintain the DC voltage constant even at higher irradiance a new algorithm is discussed in this paper. The system should be operated at OFF MPPT mode i.e., voltage regulation mode. A simulation approach is made for DC Micro-grid with Isolated Bi-directional Converter-based Battery Storage System and its performance is analyzed. A software simulation model is developed in MATLAB/Simulink. The simulated results obtained suggest that the designed PV system output voltage shows some better performance and reliability when compared to that of voltage generated by PV system operating on only MPPT mode. It can be considered for future work as a reference for zero current switching (ZCS) and zero voltage switching (ZVS) switching of the bidirectional converter for a more efficient and economical way of using it for long term application.