Photovoltaic-fed LED lighting system with SOC-based dimmable LED load

This paper deals with the design of a PhotoVoltaic (PV)-fed Light Emitting Diode (LED) lighting system including an energy storage unit. The system is aimed at exploiting the generated energy in the absence of sunshine, provided that the power absorbed by the LED load can be varied within a power range corresponding to a sufficient lighting brightness. The main focus of this work is to discuss issues related to the sizing of the main components of the lighting system, i.e., the PV panel and the battery, for a dimmable LED load. The paper proposes a battery State Of Charge (SOC)-based LED dimming allowing to minimize the components´ size. The discussion is based on the minimization of the following two quantities: 1) the excess of energy produced by the PV source, which the battery cannot store, and 2) the missing energy that the battery cannot deliver to the load. The application of the proposed methodology to a PV-fed LED-based street lighting system with dimmable LED load are presented and discussed.