Integrated Solar Controller for Solar Powered off-Grid Lighting System

An integrated solar controller for off-grid lighting system is proposed to synthesize battery charger and light emitting diode (LED) driver with the benefit of simplified system architecture and reduced system cost. Based on bi-directional converter (BDC) with Sepic and Zeta topologies, high efficient solar energy collection is realized by maximum power point tracking (MPPT) method via battery parameter, and constant current driving for LED module is implemented by digital hysteresis control strategy. Theoretical analysis and experiment results are presented to verify the validity and feasibility of the proposed control.