ABSTRACT This article proposes a cost-effective, wide-range, open-loop, and decoupled control scheme of correlated color temperature (CCT) and illuminance of a light emitting diode (LED) lamp, based on two-component color blending. Light from a phosphor-converted white LED source is blended with that from a blue/cyan LED or a red/amber LED to get a CCT value higher or lower than that of the phosphor-converted white LED CCT. Based on Grassmann’s law of color mixing and McCamy’s formula of CCT, a simple control algorithm has been implemented to manipulate the duty cycles for driving two different LED strings in pulse-width modulation (PWM) mode. The prototype lighting system has the capability to independently produce a flexible CCT ranging from 2500 K to 12,500 K and a flexible illuminance ranging from 1 lx to 100 lx at a distance of 1 m. The algorithm is experimentally validated by hardware implementation. Experimental results show that although the system is an open-loop one, it is quite accurate with respect to set point CCT and illuminance. In this two-component color blending process, mixing is possible on a straight chromatic line. A deviation from the ideal black-body radiator (i.e., increase in Duv) may be noticeable based upon the two selected LEDs’ color coordinates. This kind of dynamic LED lighting system can be used in diverse applications like road lighting, mood lighting, human photobiology research, museum lighting, etc.

中文翻译：

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一种低成本、宽范围、CCT 可调、可变照度的 LED 照明系统

摘要 本文提出了一种基于双组分颜色混合的发光二极管 (LED) 灯相关色温 (CCT) 和照度的经济高效、宽范围、开环和解耦控制方案。来自荧光粉转换白色 LED 光源的光与来自蓝色/青色 LED 或红色/琥珀色 LED 的光混合，以获得高于或低于荧光粉转换白色 LED 的 CCT 值的 CCT 值。基于 Grassmann 的混色定律和 McCamy 的 CCT 公式，已经实施了一种简单的控制算法来操纵占空比，以在脉宽调制 (PWM) 模式下驱动两个不同的 LED 串。原型照明系统能够在 1 m 的距离内独立产生范围从 2500 K 到 12,500 K 的灵活 CCT 和范围从 1 lx 到 100 lx 的灵活照度。该算法通过硬件实现进行了实验验证。实验结果表明，虽然该系统是一个开环系统，但它在设定点 CCT 和照度方面是相当准确的。在这种双组分颜色混合过程中，可以在一条直线上进行混合。基于两个选定 LED 的颜色坐标，与理想黑体辐射器的偏差（即 Duv 增加）可能会很明显。这种动态 LED 照明系统可用于道路照明、情绪照明、人体光生物学研究、博物馆照明等多种应用。可以在一条直线上进行混合。基于两个选定 LED 的颜色坐标，与理想黑体辐射器的偏差（即 Duv 增加）可能会很明显。这种动态 LED 照明系统可用于道路照明、情绪照明、人体光生物学研究、博物馆照明等多种应用。可以在一条直线上进行混合。基于两个选定 LED 的颜色坐标，与理想黑体辐射器的偏差（即 Duv 增加）可能会很明显。这种动态 LED 照明系统可用于道路照明、情绪照明、人体光生物学研究、博物馆照明等多种应用。