Energy Storage Element Sizing for Single-Phase Grid-Connected Photovoltaic Converter

Abstract

Small-scale photovoltaic (PV) systems commonly use single-phase grid-connected (GC) inverters to feed the generated power into the power grid. In this case the instantaneous GC inverter output power shows a 100 Hz fluctuation. However it is required to keep the instantaneous PV array output power as constant as possible to maximise the average PV array output power. Thus all GC inverters use an energy storage component to maintain the instantaneous power fluctuations seen by the PV array at an acceptable level. This paper analyses the relationship between the average power reduction of solar cells and the PV array voltage and current output ripple, and the relationship between the PV array output ripple and the DC link inductor or capacitor sizing.