A dimmable Ćuk half-bridge single-stage converter applied to electrodeless fluorescent lamps

A 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 Ćuk converter, as power factor correction (PFC) stage, associated with a resonant half-bridge 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 implemented by the shared switch duty ratio control, attaining a power variation from 100 W to 42 W. The implemented topology achieved a high power factor (PF), varying between 0.984 and 0.978. The line current total harmonic distortion (THD) varied from 17.538% to 11.941%, while the measured efficiency was around 80%.