Design of a Soft-Switching Asymmetrical Half-Bridge Converter as Second Stage of an LED Driver for Street Lighting Application
Design of a Soft-Switching Asymmetrical Half-Bridge Converter as Second Stage of an LED Driver for Street Lighting Application
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DOI：
10.1109/tpel.2011.2164942
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发表时间：
2012-03
影响因子：
6.7
通讯作者：
M. Arias;D. G. Lamar;F. Linera;D. Balocco;A. Diallo;J. Sebastián
中科院分区：
文献类型：
--
作者：
M. Arias;D. G. Lamar;F. Linera;D. Balocco;A. Diallo;J. Sebastián
高亮度LED由于其高可靠性、色彩多样性和不断提高的效率而被认为是卓越的照明设备。因此，出现了大量用于供应LED串的解决方案。单级解决方案具有成本效益，但效率较低，因为它们必须仅用一个转换器来实现多个目的：功率因数校正（PFC）、电流隔离（在某些情况下）和电流调节。两阶段和三阶段解决方案具有更高的效率，因为每个阶段仅针对一个或两个任务进行优化，并且它们是同时提供多个字符串时的首选选项。在本文中，提出了一个两阶段的解决方案。第一级是众所周知的PFC升压转换器。第二阶段，本文的重点，是不对称半桥（AHB）。其设计已根据基于LED的街道照明应用的需求和特性进行了优化。所提出的Transformer设计（具有不对称次级绕组）最大限度地减少了导通损耗，而死区时间期间的转换器模型优化了其持续时间，降低了MOSFET和二极管的开关损耗。实验结果表明，与40 W的原型显示效率高达94.5%，这第二阶段，并验证所提出的设计过程和模型。
High-brightness LEDs are considered remarkable lighting devices due to their high reliability, chromatic variety, and increasing efficiency. As a result, a high number of solutions for supplying LED strings are emerging. One-stage solutions are cost-effective, but their efficiency is low because they have to fulfill several purposes with only one converter: power factor correction (PFC), galvanic isolation (in some cases), and current regulation. Two-stage and three-stage solutions have higher efficiency because each stage is optimized for only one or two tasks and they are the preferred options when supplying several strings at the same time. In this paper, a two-stage solution is proposed. The first stage is the well-known PFC boost converter. The second stage, on which this paper is focused, is the asymmetrical half bridge (AHB). Its design has been optimized based on the needs and characteristics of LED-based street lighting applications. The proposed transformer design (with asymmetrical secondary windings) minimizes the conduction losses while the model of the converter during the dead times optimizes their duration, reducing switching losses in the MOSFETs and diodes. Experimental results obtained with a 40-W prototype show an efficiency as high as 94.5% for this second stage and validate the proposed design procedure and model.