A Novel Single-Stage Low-Frequency Square-Wave Driven Electronic Ballast for HID Lamps

This paper presents a single-stage, low-frequency, square-wave-driven electronic ballast for supplying high-intensity-discharge (HID) lamps with interleaved power-factor-corrections (PFC) features and a constant lamp-power control scheme. The proposed ballast integrates into a single stage an interleaved PFC converter with a high-frequency interleaving low-frequency square-wave-driven full-bridge inverter; it is able to not only offer input utility-line current shaping, but also supplies the lamp with low-frequency square-wave sources without accompanying acoustic resonance. The features of the presented ballast are cost-effectiveness, low total harmonic distortion (THD), high power factor (>0.99) and high efficiency (>90%). Theoretical analysis and experimental results of a prototype ballast for a 70 W HID lamp are demonstrated.