Análise e desenvolvimento de um conversor integrado com tensão de entrada universal e controle de intensidade luminosa para acionamento de leds

Abstract

This work presents the analysis and development of a new single-stage LED driver topology that integrates a boost bridgeless totem-pole converter operating as power factor correction (PFC) stage and a half-bridge LLC resonant converter as power control (PC) stage. The obtained single-stage converter results in an effective integration that reduces the number of switches by the half. This integrated topology aims to decrease conduction and commutation power losses and, moreover, achieving high power factor (PF), low THD and great efficiency by sharing switches. The converter is designed to have a fixed bus voltage, which is controlled by changing the half-bridge duty-cycle under universal input voltage. Since the HB duty-cycle also affects the LLC converter due to their integration, a variable inductor is employed to control the LLC impedance and achieve controlled output current for the dimming purpose. The topology aim is to obtain ZVS feature for all operating points analyzed. Once the converters of the integrated proposed topology are defined, their design is shown, as well as simulation results are presented to verify the theorical analysis, through a 100 W LED luminaire. The experimental results show voltage and current levels, as well as the functionality of the integrated topology.