Designing A Low Voltage Capacitor Less High-Efficiency Resonant Converter for AC–DC LED Drivers for Lighting Applications

Abstract

 To achieve a high- efficiency resonant converter without having a capacitor for low output voltage AC-DC LED drivers. This study proposed a system where resonant converter is used instead of asymmetrical half bridge converter. The diodes D₆, D₇, D₁₀, and D₁₁ are used for regulation purpose. MOSFETs Q₃ and Q₄ are ON and OFF with time delay of 6ms and the diode D₁₂ and D₁₃ are used to reduce the voltage level to 12V and it delivers to the load at ON time of particular MOSFET switch line. At the back end common LC filters are used, the results are verified using MATLAB SIMULINK with the output of 12V, PI control validation and SD-SR circuit. There is no need of electrolytic capacitor and the efficiency in the topology proposed is 96%. This is greater than other topology which does not use electrolytic capacitor in the same voltage range. The hardware results are verified with an output voltage of 11.6V, the output current of 5A with the power of 58W and the efficiency is above 96%. In The LED with High-Brightness (HB) is playing a vital role in lighting applications of their advantages like high reliability and high efficiency. To achieve the reliability and efficiency, the very basic method in AC-DC applications is using a two-stage topology. At the boundary conduction mode, the very general power factor correction boost converter is used at first stages. To improve reliability with low-frequency ripple in the output voltage, it is generally designed not including electrolytic capacitors. The second stage of asymmetrical half-bridge is used in the existing system. Because it has very high efficiency, operating with effective regulation and its output filter is small. But Asymmetrical Half Bridge converter closed-loop controller is very slow and it cannot readily cancel the low-frequency ripple.