微型热光电系统中一维光子晶体过滤器改进设计

Improving Design of 1-D Photonic Crystal Filter in-Micro-thermophotovoltaic System

摘要:

为进一步提高微型热光电系统的能量转化效率，在系统中设置了一维Si/SiO2光子晶体过滤器，以实现对长波辐射能的回收利用。根据光学薄膜设计理论以及传输矩阵的方法，获取了过滤器的基本结构及光学特性，并针对其第一反射带宽度过窄的缺点，采用多层膜叠加的方法，获得了一个改进结构的过滤器[1.10(L/2HL/2)](L/2HL/2)3[1.10(L/2HL/2)] [0.95(L/2HL/2)](L/2HL/2)3[0.95(L/2HL/2)]，其第一反射带宽度被拓展至2~4μm，同时在通带内也具有0.95的透射率。利用完善后的系统能量转换计算模型进行了相关对比分析，其结果表明，过滤器可在有效缓解电池冷却负荷的同时，通过提高辐射壁面的温度达到提升系统输出性能的效果，在1500mL/min的总流量下，采用改进结构过滤器的系统输出功率达到了5.46W，效率为2.6%，比采用基本结构过滤器提高了5.7%。

Abstract:

To further increase energy conversion efficiency of micro thermophotovoltaic system, a 1-D Si/SiO2 photonic crystal filter was set in the system to ensure recycle of long wavelength radiation energy. The basic structure design and corresponding optical characteristics were obtained through optical thin film theory and transmission matrix method, and an improved design [1.10(L/2HL/2)](L/2HL/2) 3 [1.10(L/2HL/2)] [0.95(L/2HL/2)](L/2HL/2) 3 [0.95(L/2HL/2)] was developed according to the narrower first reflection band of basic structure by method of multilayered film superposition, which could extend the first reflection band to 2~4μm and also had a transmission of 0.95 in the pass band. By perfecting the energy transition computational model, calculation results showed that the using of filter could effectively lower the burden of cell cooling, while at the same time boosted the temperature of radiation wall so as to raise system output performance. System output power density and total efficiency reached to 5.46W and 2.6% when using the improved structure filter at mixture flux of 1500mL/min, which was 5.7% higher than the result of using basic structure filter.