Two-stage LED street lighting system based on a novel single-stage AC/DC converter

Abstract

A two-stage street lighting system is presented, where the front stage is a single-stage AC/DC converter based on the sepic circuit and flyback converter. Since the sepic circuit and flyback converter share a switching device, the costs of the system can be reduced, and the efficiency and reliability can be improved. At the same time, the switch operates in quasi-resonant state, which reduces the switching losses and enhances the efficiency. The second stage is a light-emitting diode constant current circuit, which achieves the constant current control by adopting boost circuit in peak current control mode. A 100 W prototype is presented, which confirms the correctness of the analysis, the front stage work in the soft-switching condition and the efficiency is up to 83% when the system is in full load condition.