A single-stage LED streetlight driver with PFC and digital PWM dimming capability

摘要

This paper proposes a single-stage light-emitting diode (LED) driver that offers power-factor correction and digital pulse-width modulation (PWM) dimming capability for streetlight applications. The presented LED streetlight driver integrates an alternating current-direct current (AC-DC) converter with coupled inductors and a half-bridge-type LLC DC-DC resonant converter into a single-stage circuit topology. The sub-circuit of the AC-DC converter with coupled inductors is designed to be operated in discontinuous-conduction mode for achieving input-current shaping. Zero-voltage switching of two active power switches and zero-current switching of two output-rectifier diodes in the presented LED driver decrease the switching losses; thus, the circuit efficiency is increased. A prototype driver for powering a 144-W-rated LED streetlight module with input utility-line voltages ranging from 100 to 120V is implemented and tested. The proposed streetlight driver features cost-effectiveness, high circuit efficiency, high power factor, low levels of input-current harmonics, and a digital PWM dimming capability ranging from 20% to 100% output rated LED power, which is fulfilled by a micro-controller. Satisfying experimental results, including dimming tests, verify the feasibility of the proposed LED streetlight driver. Copyright (c) 2016 John Wiley & Sons, Ltd.