T- filters based dual-control dimmable electronic ballast

Abstract

This paper describes a method for the analysis and design of dual control dimming UHF electronic ballasts. It includes a PFC converter circuit and a T-type inverter circuit, the ballast operating at the highest point above the acoustic resonance frequency can effectively avoid the high-intensity discharge (HID) lamps acoustic resonance problems. T-type filter can achieve a very narrow depth range of dimming frequency, while achieving low lamp current crest factor, keeping the lamp current a perfect sine wave. Dimming with dual control, adjusting the duty cycle of the two frequencies to change the lamp power can reduce the EMI of FM dimming. Its effectiveness has been verified by experiments.