Análise e desenvolvimento de sistema eletrônico de iluminação com LEDs de potência empregando conversor ressonante e indutor variável

Abstract

An analysis and design of a power control stage topology for an LED (Light Emitting Diode) driver for lighting is presented in this work. The circuit is based on the resonant topology LLC-HB – resonant filter LLC type fed from Half-Bridge inverter (HB) – using variable inductor. The variable inductor is used as a part of the LLC resonant tank and allows varying the LED current furthering the lighting dimming. A normalized project methodology is proposed where the Zero Voltage Switching (ZVS) is guaranteed for the desired LED current range, according to the resonant tank series inductance schifting. The methodology allows to examinate the resonant current phase angle and also the resonant current amplitude for the established operation range. It is indispensable to properly define these parameters to assure high efficiency of the resonant tank and consequently of the entire topology. The purpose is presented as an alternative to the conventional frequency operated resonant converters. The results proves the project methodology and topology feasibility.