A novel two-stage electronic ballast for MH lamp with frequency modulation control

This paper presents a two-stage electronic ballast for metal-halide (MH) lamps with frequency modulation (FM) control scheme. The proposed electronic ballast consists of a boost power-factor-correction (PFC) converter and a half-bridge series-resonant parallel-loaded (HB-SRPL) inverter. The boost PFC circuit is operating in continuous conduction mode (CCM) to achieve high power factor, and the HB-SPRL inverter, which supplies HID lamp with a high frequency sinusoidal wave current by frequency modulation to avoid acoustic resonance. The operating principles of the proposed topology are discussed. Also, constant power control is realized using the methodology employed with a digital microcontroller. Finally, a laboratory prototype of a 400 W electronic ballast for MH lamp with universal input voltage is implemented to verify the feasibility.