基于LLC单级无桥PFC的无频闪LED驱动电源

Single-stage LED drive based on LLC bridgeless power factor correction

传统LED驱动电源通常为基于电解电容的两级拓扑结构,其效率较低,寿命周期短;去除电解电容可提高电源寿命,但会带来LED频闪。为此,本文提出一种基于LLC谐振的单级无桥PFC无电解电容无频闪的电源,采用新型无桥PFC拓扑,将其与不对称半桥型LLC谐振变换器集成单级拓扑,从而提高电源效率;为解决无电解电容所带来的LED频闪问题,在单级电源的输出端并联一双向变换器,采用电压电流双闭环控制消除造成LED频闪的两倍频谐波分量。最后,搭建一台144W的实验样机,实验结果验证所提出的单级无桥拓扑及无电解电容方案的有效性和可行性,其最高效率可达93.41%。

Conventional LED driver is based on the electrolytic capacitor two-stage topology, which has characteristics of low efficiency and short lifetime. In order to extend the lifetime of drivers, pulsating current can be used to eliminate the electrolytic capacitor, however, this method will cause LED flicker. Thus a electrolytic-less LED driver is proposed, are the driver integrates a modified bridgeless PFC with a half-bridge LLC resonant converter into a single-stage conversion circuit, and a bidirectional boost-buck converter is utilized to solve LED flicker problem. The driver features high circuit efficiency and high power factor. Finally, a 144W prototype is fabricated and tested in the lab, with the highest efficiency up to 93.4% and the experimental results demonstrate the functionalities of the proposed LED driver.