A Novel Zero-Voltage-Switching Single-Stage High-Power-Factor Electronic Ballast

This paper proposes novel zero-voltage- switching (ZVS) single-stage high-power-factor electronic ballast for fluorescent lamps. In the proposed electronic ballast, all switching devices operate at ZVS turn on and turn off. And the proposed electronic ballast only uses a symmetrical half-bridge topology to procure the functions of a boost power-factor-correction converter and a half-bridge series parallel-loaded inverter. In spite of its simplicity, an excellent performance concerning load and supply is achieved, ensuring a sinusoidal and in phase supply current. The design equations are derived from the analyzed results based on fundamental approximation, and then an easy-to- use design tool is provided accordingly under considerations of filament heating and ignition. A prototype circuit designed for one 40-W fluorescent lamps operating at 40- kHz switching frequency and 110-V line voltage is built and tested to verify the analytical predictions.