This paper presents the design and implementation of a digital high- performance
photovoltaic lighting system based on a
microcontroller. The proposed system consists of a
photovoltaic module, a LED lighting module, a bi-directional buck-boost
converter and a battery. In the paper, battery charging methods are analyzed first, and then, the control strategy and hardware implementation are proposed. The dimming control methods for LED are discussed and compared. The bi-directional buck-boost converter is the integration of a charger/discharger and a LED lighting-module drive circuit, which can fulfill maximum power point tracking (MPPT), multi-stage current charging control and LED drive control. In addition, a microcontroller (PIC16F873) is used to realize the system controller.