太陽光電系統近年來的發展蓬勃，如何降低成本與提高太陽電池效率一直是研究人員的重點。在不同的太陽光電技術中，尤其是高聚光型太陽光電系統(high concentrated photovoltaic, HCPV)搭配高功率的三五族太陽電池，在未來十年有相當潛力降低太陽光電的發電成本。三五族太陽電池僅能吸收直射的太陽日照，因此需要以高精度的太陽追蹤器對太陽做即時追蹤。 本研究為設計一實驗型太陽追蹤器，並利用被動式追蹤系統進行戶外實測。文中介紹太陽光電系統，特別強調HCPV與搭配高精度太陽追蹤器的需要，並敘述追蹤器的設計過程，最後討論此追蹤器在戶外測試與調校方法和實驗結果。 本文設計的追蹤器為方位角-仰角雙軸運動方式，利用齒輪減速機構達到375倍的減速比。追日方式以電腦計算太陽軌跡，並利用步進馬達來驅動齒輪組，以達成高精度控制的目的。本文運用Pro-E軟體進行機構設計，追蹤器可負重30 kg的太陽電池模組；方位角轉動範圍達±120°、仰角轉對範圍則是0°-90°。 追蹤器在戶外測試前，需用水平儀進行水平方向的定位，再利用指南針進行正南方的定位。本文利用精度為0.1°的視準管為角度測量器材，並利用數位相機記錄投射在視準管內的太陽光點影像，再以人為判讀偏差角度。實驗數據顯示此太陽追蹤器搭配被動式追蹤系統的平均追蹤偏差角小於0.31°，最高偏差角也在0.6°以內，大致符合原先設計追蹤器的設計目標（精度小於1o）。因此本文的追蹤器說明被動式追蹤器可搭配接受角為1°的HCPV的聚光模組，對日後設計大型高精度的太陽追蹤器有相當參考價值。 Increasing the solar cell’s efficiency while reducing the cost of solar cell is the main focus of the research of photovoltaics technology. High concentrated photovoltaic (HCPV) system uses III-V solar cell, have a great potential of reducing the cost of electricity power in next ten years. However, the III-V solar cell only absorb the direct solar irradiation and it needs to be mounted on a solar tracker with high accuracy. In this study, an experimental solar tracker is designed and tested its passive tracking performance at outdoor. The general requirement of photovoltaics system is introduced first and the necessity of high accuracy of solar tracker is highlighted for coping with HCPV. Next, the process of mechanism design with the Pro-E software is described. This tracker can support a solar panel with 30 kg, and rotate with the range of azimuth and altitude ±120° and 0°-90°, respectively. Calibrating procedure in the horizontal position and south-north orientation is performed before the outdoors test. Then a collimating tube with 0.1° precision is used to measure the off-tracking angle. Result shows that the average off-tracking angle is about 0.31° and maximum off-tracking angle is about 0.6°. This demonstrates the feasibility of the passive sun tracker can be used in HCPV system with an optical module of 1° acceptance angle.
