用于驱动多个LED串的电容电场无线能量传输系统的研究

The LED lamp, which is seen as the third revolution in the history of lighting technology, is increasingly popular in recent years since it offers many advantages over traditional light sources, such as higher luminous efficacy, longer life expectancy, and non-pollution to the environment. Meanwhile, contactless power drivers for driving paralleled LED strings can offer several operational merits, including easy and safe operation, waterproof and maintenance free. Moreover, wireless LED lamps can also be applied in flammable and explosive or underwater systems. Thus, this project focuses on the capacitive wireless power transfer system for driving multiple LED strings, including mainly three parts. (1) A new method for improving the efficiency significantly is proposed by analyzing the characteristics of capacitive wireless power transfer. (2) A new current-balancing structure for wireless power transfer system is proposed by analyzing the influence of capacitive wireless power transfer on current-balancing for multiple LED strings. (3) A new detection and energy-recycling network is proposed for detecting the electric coupling of capacitive wireless power transfer system and the working state of LED strings. In order to make sure the accurate current-balancing ability is achieved in any case through the energy flowing bidirectionally in the system, the energy-recycling network is activated or stopped realtimely according to the information of detection network. Therefore, this project holds both important scientific value and practical applicability, and will provides strong theory and technology support for capacitive wireless power transfer system to drive multiple LED strings.

LED灯，堪称人类照明史上的第三次革命，具有发光效率高、寿命长、无污染等优点，从而越来越受到人们的欢迎。而无线LED灯则更是拥有安全，易操作，防水，免维修等优点，并可应用于易燃易爆或水下系统。因此，本项目针对驱动多个LED串的电容电场无线能量传输系统进行深入研究, 主要包括：（1）分析电容电场无线能量传输的特性，提出一种可显著提升无线能量传输效率的方法；（2）分析电容电场对LED串电流均衡的影响，提出一种基于无线能量传输系统的电流均衡结构，进一步降低LED串的电流均衡误差；（3）提出一种新型检测及能量回馈网络，检测电容电场无线能量传输系统中电场的耦合情况和LED串的工作状态，并实时根据检测信息激活或停止能量回馈网络，达到系统能量的双向流动，以确保系统在各种情况下均具备精准的电流均衡能力。本项目的研究将为驱动多个LED串的电容电场无线能量传输系统的实际应用提供强有力的理论和技术支持。

基于电容电流均衡原理，本项目提出了一种完全独立的电流控制拓扑结构。该结构建立于半桥谐振变换器之上，同时谐振的电容还起到了电流均衡以及电气隔离的作用。每个LED串采用并联开关管的方式，避免因开关管串联而导致的电流尖峰流入LED而减少LED的寿命。与SIMO（Single- Inductor-Multiple-Output）结构相比，该结构模块之间完全相互独立，没有交叉耦合问题。即该结构中的模块可以任意开通与关断，不受其他模块的任何限制与制约。即使在极端情况下，所有模块都完全关断，主电路仍可以正常运行。基于颜色理论中的杠杆原理以及电力电子学中的滞环控制原理，本项目提出了一种LED混色系统色度坐标精准跟踪控制算法。首先，根据CIE1931色度空间中的杠杆原理，利用目标色度坐标值与混色点的色度坐标值，计算出不同颜色LED串的光通量比。然后，在不需要任何温度传感器的情况下，利用滞环控制原理，最大限度地减小了由于老化和温度效应引起的色差漂移。此外，利用PI算法通过控制所有通道占空比的总和，对整个系统的光通量输出进行控制。本项目构建了一个由RGB 三个LED串组成的实验模型进行验证。其中，每个LED串由12个LED组成。实验结果表明，任何LED串的开通与关断，都不会影响其他LED串的正常工作，以及各个串之间的电流均衡。同时，主电路的开关网络实现了软开关技术。进一步通过实验验证，该控制算法可以使得光通量输出控制在100lm到600lm之间，误差在±2%以内；RGB所对应的混色点围成的三角形内的任意色度坐标均可精确控制，在CIE1976色度图的整个色域内，输出坐标与参考坐标之间的距离均小于0.007。