The Effect of Multiple PV and Battery Penetration on Stability of DC Microgrid with Single Bus Topology

Solar Photo-voltaic (PV) power generation has played a significant role in the development of microgrid technologies. Nowadays, there is large penetration of PV units into the grid and the stability of the overall system may get affected when a new Distributed Energy Resource (DER) is added to the system. In this paper, stability analysis of a DC microgrid with single as well as multiple PV units and battery is carried out using the transfer function model. A DC microgrid having a single bus topology and multiple DERs, controlled using multi-loop control is considered for the analysis. The effect of penetration of DERs on the stability of the system is investigated using the eigenvalue approach. A system with communication delay is also considered for the analysis. From the analysis it can be seen that, addition of a new DER unit into the system affects the stability and hence the controller gains needs to be re-tuned to bring the system back to the stable state.