【作者】 陈越；

【导师】 钱照明；

【作者基本信息】 浙江大学 ， 电力电子与电力传动， 2012， 硕士

【摘要】 在大力倡导低碳节能的今天,高效节能是照明行业的重要发展方向,LED光源作为绿色、节能、省电、长寿命的第四代照明灯具得到了迅速发展,为照明界开拓出了一个全新的技术领域。高效率的大功率LED驱动器也成为一个研究热点。在此背景下,本课题主要针对高效率的大功率LED驱动器进行研究,探索高效率LED驱动器的电路拓扑和优化设计方法。在此基础上,针对用于两路LED驱动器的无源均流方法进行研究,并进行参数、效率优化。本文重点研究谐振型高效率LED驱动器的分析设计。主要分为两个方面。首先是高效率单路LED驱动器的设计,在分析对比一些电路拓扑的基础上,采用LLC谐振拓扑,提出一种适用于宽范围恒流输出的设计方法,并进行效率优化。主要研究内容包括电路原理分析、工作区间设计、恒定输出电流的增益曲线推导,设计时需要考虑的因素、各个主要设计参数对整机效率的影响、以及提出最终的高效率优化设计流程,最后构建样机用实验的方法验证设计方法的可行性。本课题另一重要内容则是在单路输出LLC谐振型拓扑的基础上,在变压器副边串联一个电容,使之成为一个可以实现两路自动均流的四元件谐振电路,将单路的全桥整流结构拆成两个半波整流电路,即构成了两路输出。串联的电容可以使两路输出自动均流。主要研究内容包括对提出的LLCC四元件谐振电路在CCM和DCM模式下的工作模态、均流原理进行分析,推导电路的交流等效电路、直流增益曲线以及恒定输出电流的增益曲线,分析了几个设计关键参数,最后构建样机进行实验,给出实验结果和分析。更多还原

【Abstract】 In order to meet the requirement of low-carbon and Energy conservation, high efficiency and energy conservation has become the most important developing direction in lighting industry. As the most potential illuminant, LED possesses many merits such as high efficiency and long life, thus has become a hot topic and developed rapidly in recent years. High efficient high power LED driver has become a research hotpot as well. Based on this background, this project mainly research on high efficient high power LED driver, including the circuit topology and optimization design methodology. A novel LLCC resonant converter with precise current sharing for two-channel LED driver is also discussed.The research in this paper mainly includes two aspects. First is the design of high efficient single output LED driver. LLC resonant converter is chosen as the most efficient topology based on some analysis and comparison. A new design method which is suitable for wide output range application is proposed in this paper. Circuit principle analysis, working region selection, DC characteristic deduction and optimization of design parameters are also discussed in detail. Based on the analysis and discussion, a detailed optimal design procedure is proposed. Finally, a 140W experimental prototype is built to verify the design and proved a high efficiency after optimization.Based on the single output LED driver, a LLCC resonant converter with automatic precise current-sharing is proposed for two-channel LED driver. With a resonant capacitor connected in series with the transformer secondary winding, the currents of the two channels are precisely shared even for different LED strings with different voltage drops. The circuit operation principle under both CCM and DCM modes, current sharing principle, AC equivalent circuit analysis, DC gain deduction and design considerations are discussed. A prototype of 140W two-channel LED driver is built to verify the proposed current sharing circuit.更多还原