太陽能電池之輸出功率隨著陽光的入射角度不同而有所變化，欲提昇輸出功率，就必須使太陽能板在任何時刻都正對著太陽。隨著高聚光型太陽能電池的發展，追日控制器的追蹤角度誤差要求也愈加嚴苛。一般追日控制器不外乎利用光感測器或太陽軌跡公式來進行追蹤，但前提是機構安裝誤差要小、定位必須精確，而且機構會因長時間使用而出現老化變形，需要時常校準、維護機台與追蹤器之間的整合狀況，即使能達到非常精準的追蹤效果，卻必須犧牲許多心力，造成發電成本昂貴。 本研究初步利用小功率太陽能電池本身的發電量—短路電流作為追蹤的衡量基準，在直流-直流轉換器的運作過程當中，適時且迅速量測短路電流作為追蹤訊號，用以進行太陽追蹤。如此一來將可不必考慮機構安裝誤差及定位準確度，並且在機構老化變形時依然能夠找到最大功率輸出的位置，除了能省去光感測器的精密安裝與角度編碼器等硬體的使用，也減少許多不必要的維護、校準成本。實際將控制器使用在高聚光型太陽能板時，在微小角度誤差範圍以內的追蹤有不錯的性能表現。 The output power of the solar cell varies with the varying incidence angle of the sun, so the PV panel must be kept facing the sun directly at any time if we want to rise its output power. Recently, the requirement of tracking error of angle is more and more strict with the development of High Concentrated PV. In general, either photo-sensor or sun trajectory formula is adopted in the controller for sun tracking, but the controllers works on the premises that, the error of mechanism set up should be small, the orientation should be fixed accurately, and the mechanism will be aging after using a long time, so the system should be calibrated and maintained usually. Even though the tracking results are precise, many things were then sacrificed, this will cause the cost of electric-power-generating to be more expensive. This thesis uses the short-circuit current of a solar cell which has a small output power to be the consideration in order to do tracking, the short-circuit current is then measured fast during the process of the operation of DC-DC converter. Thus, the error of mechanism set up and the orientation-fixing accuracy need not to be considered, and the tracking angle that the PV outputs maximum power will still be met. The exact fixing of photo-sensor and the using of encoders will then be left out and the unnecessary cost of calibration and maintenance will be reduced in this way. The tracking performance of the used controller is pretty good in a small range of angle when it is used for the High Concentrated PV system.
