太陽能板最大功率點模糊控制追蹤器設計與追日系統實現

Abstract

最大功率點追蹤技術(MPPT)常被用於光伏(PV)系統中以解決低能量轉換效率以及深受周遭環境影響的問題。在此技術中，以擾動觀察法為主的方法深受歡迎，因其演算法簡單且易於實行。然而，此類方法具有響應速度不足之缺點，此外也會在最大功率點(MPP)附近產生嚴重震盪，造成電壓切跳且導致平均輸出功率偏離最大功率。因此本論文提出模糊邏輯控制器(FLC)用以改善上述缺點。模擬結果顯示，模糊控制器不僅響應速度快，亦可確實消除電壓切跳而使輸出功率更加穩定。而在實驗中，模糊控制器確實大幅降低了震盪使得電壓切跳比率落在1%以下，同時也具有快速的響應表現，在5秒內到達最大功率點。此外，本論文利用電子羅盤以及太陽軌跡，實現了一套雙軸追日系統，並以簡易日晷檢視太陽能板與陽光之間的夾角多落在5度以內，具有不錯的追蹤表現。

MPPT technique is often used in PV systems to solve low efficiency problem in energy conversion which is deeply affected by surroundings. In MPPT, methods based on the concept of P&O are very popular since their algorithms are simple and easy to implement. However, this kind of methods has a slower response and often encounters severe oscillation during steady status. Such oscillation causes the average output power level deviated from MPP and makes the voltage chattering around MPP. Therefore, this thesis proposes a FLC method to improve the above shortcomings. Simulation results show that the FLC not only has a fast response, but also eliminates the oscillation to keep the output power steady and smooth the voltage without chattering. Similar to the simulation, the experimental results show that the FLC can fast drive the system to MPP in 5 seconds and highly reduce the oscillation so that the ratio of voltage chattering is below 1%. In addition, this thesis uses the compass sensor and solar trajectory to set up a dual-axis solar tracking system. A simple sundial used to check the angle between the solar panel and sunlight is less than 5 degrees in most of the day, which implies a good performance of solar tracking.