新一代自激式LED照明驱动电路关键技术的研究

To develop LED lighting has been one of the focuses of the global industries. As the most important parts of the LED lighting products, the present LED lighting circuits still have technology bottlenecks. It is urgent to develop the next-generation LED lighting driving circuits. From the viewpoint of power electronics, 3 key technologies for the next-generation LED lighting driving circuits are reviewed. One is about the circuits of high efficiency, long lifespan, and low cost. The other two are about the temperature-adaptive control strategies to slow down the LED lumen depreciation and the high-precision dimming techniques to reduce the LED chromaticity shift, all of which should satisfy the visual characteristics of human eyes. The research will be carried out gradually with the focus of the abovementioned 3 key technologies. Firstly, the self-oscillating circuits of high price performance ratio will be studied and invented. Some appropriate ones will be found out to be the next-generation LED lighting driving circuits. Secondly, based on the self-oscillatig LED lighting driving circuits, a hysteretic plus repetitive current control method including the concepts of visual characteristics of human eyes and LED operating temperature management will be studied, and the effect of slowing down the LED lumen depreciation will be evaluated. Finally, based on the temperature-adaptive hysteretic plus repetitive current control method, a multi-level PWM dimming method of high precision will be studied, and the effect of reducing the LED chromaticity shift will be evaluated. The project objective is to set up some theoretical and technological fundamentals for developing the next-generation LED lighting driving circuits.

发展LED照明已成为全球产业的焦点之一。作为LED照明产品中最重要的组成部分，目前的LED照明驱动电路还存在着技术瓶颈。发展新一代LED照明驱动电路迫在眉睫。项目申请人从电力电子学的角度评论了新一代LED照明驱动电路的3大关键技术：（a）高效率、长寿命、低成本的电路，（b）符合人眼视觉特征的以减缓LED光衰为目标的具有温度适应性的控制策略和方法，（c）符合人眼视觉特征的以减少LED色度漂移为目标的高精度调光技术。聚焦上述3大关键技术，项目组将层层递进、环环相扣地开展研究。首先研究和创新高性能价格比的自激电路，发掘出适用的新一代LED照明驱动电路。然后，研究融入人眼视觉特征和LED工作温度管理概念的滞环＋重复的电流控制方法，评估其对减缓LED光衰的效果。最后，研究高精度的多电平PWM调光技术，评估其对LED色度漂移的效果。本项目旨在为发展新一代LED照明驱动电路奠定理论和技术基础。

为促进LED照明驱动技术的发展，本项目着眼于解决当前LED照明驱动电路面临的技术难题。截至目前，所取得的重要结果包括：已创新并实现了一系列高性能价格比的自激式LED照明驱动电路；在上述自激式电路的基础上，进一步挖掘元器件的固有工作特性，提出了一种低成本的输入自适应控制方案，实现了宽工作范围内电路输入/输出功率的近似恒定，以此来缓解LED的光衰和色度漂移问题（包括温度因素）；更进一步，基于所提取的R-LED、G-LED、B-LED的光电特征参数，另辟蹊径地提出了一种符合人眼视觉特征的更高精度的RGB-LED混色调光控制方案，以此来规避W-LED的色度漂移问题。