Double-flyback half-bridge electronic ballast to supply HPS lamps

This paper presents a high power factor electronic ballast for high pressure sodium lamps (HPS). The ballast consists of a single switch double-flyback and a half-bridge inverter. The double-flyback is responsible for PFC and lamp current limiting. The inverter stage supplies the lamp in a low frequency square waveform, avoiding lamp re-ignition and acoustic resonance phenomenon occurrence. Ballast project and experimental results are presented in order to verify the feasibility of the proposed topology.