A Novel Single-Stage High-Power-Factor LED Power Supply with Soft-Switching Feature for Streetlight Applications

This paper presents a novel single-stage LED power supply with soft-switching feature suitable for streetlight applications. The proposed AC-DC LED power supply integrates an interleaved buck converter with coupled inductors and a half-bridge LLC resonant converter into a single-stage power-conversion circuit with reduced voltage stress on the DC-bus capacitor and power switches. Furthermore, coupled inductors in the interleaved buck converter are designed to be operated in discontinuous-conduction mode (DCM) for carrying on power-factor-correction, and the half-bridge LLC resonant converter features zero-voltage switching (ZVS) to reduce switching losses of power switches, and zero-current switching (ZCS) to decrease conduction losses of power diodes. A 144 W (36V14A)-rated LED prototype circuit is successfully developed and implemented for supplying an LED streetlight module and operating with a utility-line input voltage of 110 V. High power factor and satisfying efficiency are achieved in the proposed LED power supply for streetlight applications.