Assessing Control of Battery-Supercapacitor Hybrid Storage System in Photovoltaic Based DC Microgrid

Photovoltaic (PV) energy in a DC microgrid enables variable power generation due to change in solar irradiation and ambient temperature. Hence, there is an essential requirement for an energy storage medium to tackle this issue. Battery is a primarily energy storage medium than can be used to overcome the intermittency involved with PV. However, battery alone is insufficient if there is a transient variation in the load demand. Thus, hybrid energy storage system i.e., battery and supercapacitor (SC) have strong application in a DC microgrid to balance the power flow between renewable energy source i.e., PV and load. In this chapter, a power sharing control strategy between PV and load demand in DC microgrid is investigated. This control strategy commands the MPPT DC-DC converter, and bidirectional DC-DC converters associated with battery and SC. By employing this control strategy, the reference currents for both the energy storage mediums are calculated such that the sudden variation in load demand can be met by SC whereas the average load demand met by the battery. The distribution of power between battery and SC is facilitated by utilizing a low pass filter such that the peak current is transferred to the SC whereas the average current is taken care by battery. The simulation results shows that this control strategy provides the effective power sharing between PV and hybrid energy storage medium i.e., battery and SC.