Low-frequency burst modulation applied to single-stage SEPIC half-bridge topology to feed an electrodeless fluorescent lamp with dimming capability

This paper presents the design and development of an electronic ballast for electrodeless fluorescent lamps operating at 250 kHz. In this system, a dimming control based on a low-frequency modulated PWM signal is proposed. The topology is composed of a Single-Ended Primary-Inductance Converter (SEPIC), used as power factor correction stage, integrated with a resonant half-bridge inverter, used as the lamp power control stage. The integration of both stages is proposed in this paper, in order to reduce the number of active switches, as well as to simplify the required driving and control circuit for this application. Experimental results demonstrate the feasibility of the proposed solution that achieves 74% lamp power dimming (from 100 W down to 26 W). The implemented topology achieved a high power factor (0.99) with efficiency around 86%.