平行機構於兩軸太陽追蹤裝置之控制

Abstract

目前市面上雙軸的追日系統大多都是採用仰角-方位角串聯式機構為主，此型態的追日系統在正中午時，太陽軌跡會出現轉折點與短時間內大變化量的情形。本研究欲建立四百瓦聚光型太陽能模組的平行架構式追日系統，平行式機構相對於串聯式機構具有高負載能力、高剛性、低累積誤差的特性，且太陽軌跡上較為平滑而沒有轉折點的產生，在控制上較傳統的追日系統穩定。追日系統在控制的部分採取混和式的控制方法，是由演算法計算的太陽軌跡先進行機構的定位，再藉由光感測器訊號換算追蹤誤差，根據追日機構的操作點與追蹤誤差量進行閉迴路補償。在八月份的追日實驗中，誤差角度θ_1與θ_2可以維持在0.2度左右，太陽能模組發電量大約為250瓦。

Currently, most of dual axis tracking systems is based on tandem elevation-azimuth serial mechanism. But this type of mechanism will appear singular point and will appear dramatic position changes in the short time at noon. This study intends to build four hundred watt high concentrated photovoltaic parallel architecture tracking system. Compare to series type mechanism, parallel mechanism has high load capacity, high rigidity and low accumulative errors. In addition, the sun position trajectory is much smoother without appearing singular point and more stable than traditional tracking system. In parallel type tracking system, the design of the control loop use hybrid control, which is calculated by algorithm to confirm the sun location first then start to tracking the sun trajectory. Then the tracking error is feedback by translating the signal which the sun sensor received. Finally, the closed loop compensation is according to tracking operating point and the sun sensor errors. In August tracking experiments, the error angle theta1 and theta2 can be maintained at 0.2 degrees, and solar modules generate about 250 watts.