提出了一种基于脉冲宽度调制(PWM)的三基色发光二极管(LED)调光调色计算模型，建立了混合光的色品坐标与占空比、相关色温与占空比、最大光通量与色品坐标的函数关系。采用红绿蓝(RGB)三基色LED 进行实验验证，实验结果表明：计算模型能较好的指导LED 光色调节，混合光色品坐标的理论值和测量值之间的误差小于2.5%，模拟太阳光的色温变化误差仅为50 K。该计算模型可应用于各种三通道LED 的调光调色，其高精度的优点能更精确地实现智能照明，极具实用价值。

This paper presents a dimming method that based on three channels′ pulse- width modulation (PWM) and light- mixing technology. A quantitative calculation model is established among chromaticity coordinate, correlated color temperature and three channels′ duty cycles. The functional relationship between chromaticity coordinate and maximum luminous flux is also setuped. This method has been verified favorably by light mixing experiments with tricolor LED, which shows that the deviation of chromaticity is less than 2.5% between the theoretical value and the measured value. In addition, the color temperature change of sunlight has been simulated by this quantitative calculation model, and the deviation of CCT is less than 50 K. This model with the advantage of high precision can be applied to various types of LED dimming color and has a beneficial value for practicality.