Dimmable high power factor single-stage electronic ballast for electrodeless fluorescent lamps

Abstract

Dimmable high-power-factor electronic ballast is proposed in this paper. The electronic ballast is intended to feed a 100 W electrodeless fluorescent lamp (EFL) at 250 kHz. The proposed topology consists of a buck-boost converter, as power factor correction (PFC) stage, associated with a resonant halfbridge inverter, used as lamp power control (PC) stage. In this work, the integration of both stages is proposed in order to reduce the number of active switches, as well as to simplify the required driving and control circuitry for this application. The dimming system is employed by the shared switch duty ratio control, the power variation oscillated from 100W to 44W. The implemented topology achieved a high power factor (PF), varying between 0.992 and 0.979, the line current total harmonic distortion (THD) varied from 10.016% to 6.78%, while the measured efficiency was around 80%.