N. Farrar and M.H. Ali
University of Memphis,
Keywords: solar photovoltaic system, supercapacitor energy storage, distributed energy resources, power grid stability
Summary:This work proposes to design and operate a grid-connected solar photovoltaic (PV) system as a supercapacitor energy storage (SES) during night time or intermittent cloud insolation conditions as well as during day time. According to the proposed approach, a supercapacitor to be connected at the PV panel terminal through a switch will be charged during day time. At night time, the PV panel will be disconnected naturally. Consequently, the charged supercapacitor connected as the input to the DC-DC converter and the rest of the PV system components (except the MPPT controller) will constitute the SES unit that can be used for dynamic performance improvement of the grid-connected network that may have other distributed energy resources (DER) and various flexible loads. During daytime, following any disturbances like any faults in the network, the PV panel will be disconnected for a very short time, and the SES unit will control both reactive and active powers, thereby providing both voltage and frequency support to the grid. Once the power grid stability is maintained, the PV panel will be connected back to the system and operate normally. Thus, the proposed approach can provide a seamless and robust operation of the grid-connected PV system.