Near-Unity Power Factor Electronic Ballast Based on Integration Techniques to Drive High-Intensity Discharge Metal Halide (HID–MH) Lamps

This paper presents a single-stage converter to drive high-intensity discharge metal halide lamps. The integration of two discontinuous conduction mode boost converters, in an interleaved way, with a half-bridge voltage inverter and the use of a square-current waveform applied to the lamp, results in an electronic ballast with high power factor and reduced power spectrum spread, avoiding fluctuations inside the discharge tube. To stabilize the lamp current and power, a feedback control loop was designed and implemented. The overall result was a ballast with an efficiency of 90% and a power factor above 0.98.