An improved topology of electronic ballast with wide dimming range, PFC and low switching losses using PWM-controlled soft-switching inverter

This paper presents a novel improved topology of voltage-fed soft-switching LCrCdc series-parallel quasi-resonant inverter with a constant-frequency for electronic ballast applications. This new topology introduces a low-cost solution to reduce switching losses to achieve high-efficiency ballast. A symmetrical pulse wide modulation (PWM) control scheme is implemented to regulate a wide range of output power. Switching losses effect on ballast efficiency is discussed through experimental point of view. In this discussion, an improved topology in which accomplishes soft-switching operation over a wide power regulation range is proposed. Energy consumption of this new circuit is decreased by using reverse recovery attribute. Additionally, a power-factor correction (PFC) circuit is employed to make the line current follow naturally the sinusoidal line voltage waveform. Simulation results are favorably verified with the experimental measurements in 20 Wballast-lamp laboratory prototype. Different load conditions are provided in order to clarify the behavior of the proposed converter. (C) 2007 Elsevier B.V. All rights reserved.