SINGLE-SWITCH HIGH-POWER-FACTOR ELECTRONIC BALLAST FOR COMPACT FLUORESCENT LAMPS

摘要

A novel single-switch high-power-factor electronic ballast is designed for compact fluores- cent lamps. The circuit configuration is originated from the integration of a buck-boost power-factor-corrector (PFC) and a Class-E load resonant inverter. Design equations are derived based on fundamental approximation and computer analyses are performed to determine circuit parameters. By operating the buck-boost converter at discontinuous conduction mode (DCM), the electronic ballast can achieve nearly unity power factor. With carefully designed circuit parameters, the active power switch can be switched on at relatively low voltage, leading to a high circuit efficiency. A prototype for a 27-W compact fluorescent lamp was built and tested to verify the analytical predictions. Satisfactory performances are obtained from the experimental results.