双脉冲下混合白光LED集成照明系统动态颜色理论及应用研究

Mixture white LED integrated lighting systems perform high luminous efficacy and wider range for color-controlled. The color characteristics for mixture white LED system have complex mechanisms, because LED systems perform non-identical thermal and optical performance based on non-identical heat distributioin which in a pratical situation. So far, most reports focus on steady-state color charateristics for LED device under DC or PWM operation. For dynamic color theory for mixture white LED system under double-pulse operation, scientists have not clearly studied and clarified. Based on thermal time constant spectrum,the proposed project can in principle be innovative theory to study dynamic interactions and mechanisms for peak wavelength of LED chips. This project proposes an original idea to investigate dynamic multiphysics model for peak wavelength in LED systems by genetic algorithm, which can clearly clarify the dynamic interactions on phosphor mechanism of white LED and mixture spectra for mixture white LED systems. The dynamic junction temperature response for LED systems under double-pulse operation is highly dependent on bi-level current intensity, duty cycle, thermal coupling, thermal resistance-capacitance topological structure for system, which are developed and evaluated by using dynamic compact thermal resistance-capacitance model for LED systems. Dynamic photo-electro-thermal theories for LED systems will be used throughout this model as the basis for dynamic luminous flux and color model of mixture white LED systems, which have been given to guide LED system designers to dynamically control color characterisitcs of mixture white LED systems. The proposed idea opens a new research opportunity to dynamic color model for mixture white LED integrated lighting system under double-pulse operation.

双脉冲下混合白光LED集成照明系统具有光效高、颜色调节范围广等优点。双脉冲下白光LED器件颜色特性不同于直流和PWM模式，且系统中的LED光源特性参数存在显著差异，即各器件结温为非均匀分布，然而目前大部分研究集中于直流或PWM模式下单颗LED器件的颜色稳态特性，对双脉冲下混合白光LED系统的颜色动态特性仍缺乏相关研究。因此本项目将提出通过遗传算法和热响应时间常数谱构建LED芯片峰值波长的动态多物理场模型，进一步阐明白光LED荧光粉能量转换及混合白光合成光谱的动态特性。基于LED系统瞬态热阻-热容网络模型，研究双脉冲下系统的二阶电流幅度、占空比、系统热阻-热容网络拓扑结构、热耦合等因素与系统结温动态响应的联系规律；并结合动态LED系统光-电-热多物理场模型的功能性表达，建立混合白光LED系统动态光通量-颜色模型，从而为动态控制混合白光LED系统的颜色特性提供新的改进思路。

混合白光LED集成照明系统的颜色存在复杂动态变化规律，然而目前大部分研究集中于直流或PWM模式下白光LED器件的颜色稳态特性，对于双脉冲下混合白光LED系统的颜色动态特性及应用研究仍缺乏相关研究。.本项目完成建立GaN基 LED芯片峰值波长动态多物理场模型，在双脉冲驱动模式下，二阶电流的幅度分别0.342A、0.04A，占空比为0.5，色温波动范围为176K；依据所提出的理论模型，将二阶电流幅度控制为0.51A、0.12A，色温波动范围降低为45K。通过所构建双脉冲下LED芯片峰值波长与二阶电流、结温、占空比之间动态多物理场模型，阐明颜色动态变化的内在联系规律及机理。.本项目通过建立非均匀热学特性分布的LED系统动态光通量&色温模型，混合白光LED集成照明系统色温变化范围为3200K-5200K，混合光通量变化范围为1000lm-3900lm，基于所建立的动态光通量&色温模型，测试值与理论值平均误差为5.9%，最大误差为7.8%。通过本项目研究成果阐明光通量&色温与电功率、温度响应、频率、占空比之间的功能性表达，从而为动态控制混合白光照明系统输出光通量及颜色特性提供重要参考依据。.通过本项目完成构建LED荧光粉能量转换机制及合成光谱动态特性。研究测试计算，芯片到封装顶部的热流路径上，硅胶封装热阻为21.3℃/W，荧光粉封装热阻为16.8℃/W，荧光粉厚度0.5mm，荧光粉吸收系数28.3cm-1，荧光粉转换系数48.7cm-1，基于本项目提出的荧光粉特性模型所计算的结温、热功耗系数、光通量，与实验测试比对，两者误差在4%以内。.本项目以系统的平均结温和热流均匀性为目标函数，通过遗传算法优化LED集成模块的叉排阵列结构，常规LED矩形阵列系统在不同负载电功率情况下，系统平均结温分别为84.6度，102.7度，121.4度，139.8度；经过本项目优化的LED叉排阵列系统的平均结温分别为81.6度，97.9度，115.8度，123.5度。研究成果表明经过本项目优化的LED叉排阵列系统结温明显下降，热流分布均匀性明显提高，系统可靠性得到加强。.通过以上系统研究工作，圆满完成项目原计划研究目标，相关成果发表在10篇期刊论文，SCI一区期刊3篇，SCI二区期刊2篇，SCI三区期刊1篇，EI收录期刊论文4篇，申请美国发明专利1项，中国发明专利6项。

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