A high efficiency HPF-ZCS-PWM Sepic for electronic ballast with multiple tubular fluorescent lamps

This paper presents a high efficiency Sepic rectifier for an electronic ballast application with multiple fluorescent lamps. The proposed Sepic rectifier is based on a zero-current-switching (ZCS) pulse-width-modulated (PWM) soft-commutation cell. The high power-factor of this structure is obtained using the instantaneous average-current control technique, in order to properly meet IEC61000-3-2 standards. The inverting stage of this new electronic ballast is a classical zero-voltage-switching (ZVS) half-bridge inverter. A proper design methodology is developed for this new electronic ballast, and a design example is presented for an application with five fluorescent lamps 40 W-T12 (200 W output power), 220 V/sub rms/ input voltage, 130 V/sub dc/ dc link voltage, with rectifier and inverter stages operating at 50 kHz. Experimental results are also presented. The THD at input current is equal to 6.41%, for an input voltage THD equal to 2.14%, and the measured overall efficiency is about 92.8%, at rated load.