聚光型太陽能電池之聚光鏡設計

Abstract

太陽能發電技術HCPV利用大型聚光型透鏡如菲涅爾透鏡來達到聚光的效果，且此透鏡可使用成本較低的塑膠材質製作。另外HCPV系統還利用小面積且轉換效率可達到約40%之三五族太陽能電池來達到較少半導體材料使用的目標。HCPV系統的優勢在於較小的太陽能電池面積、較高的轉換效率與較低的成本。但它的缺點則是較小的接收角，大約±1∘。因此太陽能追蹤系統對於HCPV系統來說是必要的。已商品化的太陽能追蹤系統的精度大約為1∘。為了降低太陽能追蹤系統的能量消耗與追蹤誤差，在本論文中利用ZEMAX®設計了有較大接收角的聚光模組。在此設計中原本聚光鏡的對稱性被改變來達到將光分為兩個方向處理的目標。在此聚光模組中加入了導光管與兩個透鏡，在太陽光入射角度偏移時，可收集更多的光到太陽能電池上。此聚光模組在GCR為400的情況下，可達到±10∘的太陽光接收角。如此一來，太陽能接收系統每天僅需要轉動9次。也因此可以大量減低追蹤系統的能量消耗。

High concentration photovoltaic (HCPV) utilizes point-focus cost-effective plastic Fresnel lens and a millimeter-sized Ill-V compound multi-junction solar cell is placed underneath focusing optics which can achieve cell efficiency potential of up to 40.7 %. The advantage of HCPV makes less solar cell area and higher efficiency; however, the acceptance angle of HCPV is about ±1∘, which is very small and the mechanical tracking of the sun is necessary. In order to reduce the power consumption, system cost and the angle tracking error of tracking systems, a light collector model with larger acceptance angle is designed with ZEMAX®. In this model, the original radially symmetric Fresnel lens of HCPV is replaced by cylindrically symmetric Fresnel lens and a parabolic reflective surface. Light is collected in two dimensions separately. And a couple of lenses and a light pipe are added before the solar cell chip in order to collect more light when sun light deviates from incident angle of 00. An acceptance angle of ±10∘ is achieved with GCR (geometric concentration ratio) 400.