Three phase converter with galvanic isolation based on loss-free resistors for HB-LED lighting applications

Abstract

This work presents a driver for High-Brightness Light-Emitting Diodes (HB-LED) in three-phase grids, which complies with IEC 1000-3-2 Class C requirements, achieves high Power Factor (PF), low Total Harmonic Distortion (THD), as well as, the capability to achieve full dimming while disposing of the bulk capacitor and having galvanic isolation. The HB-LED driver is based on the use of six four-port cells with their inputs connected to the three-phase network and their outputs connected in parallel. Each one of these cells is a DC/DC converter operating as a Loss-Free Resistor (LFR) based on the concept of a flyback operating in Discontinuous Conduction Mode (DCM). Moreover, it operates in the full range of the European three-phase line voltage, which varies between 380V and 420V, and it supplies an output voltage of 48V with maximum power of 90W.