風力發電機的強韌控制系統設計

Abstract

本論文探討風力機的控制器使用不確定因素：功率係數的參數時，對整體風能轉換系統的影響。因為功率係數主要是製造商透過實驗或模擬獲得。在不同氣候的變化或是遇到機械老化的問題，實際的模式可能跟製造商提供的模式產生誤差，導致輸出功率不如預期。為了改善這個問題，本論文在最大功率追蹤(maximum power point tracking, MPPT)使用擾動觀察法(perturbation and observation, P&O)來設計參考轉速ω_ref；功率調節(power regulation, PR)則是使用PI控制器來設計，並且透過回授線性化的方式消除磁通狀態方程式的非線性項，藉此獲得一個轉子電壓控制方程式，並以此方程式適當的將風力機控制在MPPT或PR模式下。最後透過模擬的方式與現有的控制器比較，藉此驗證所提出的控制方法在實際的功率係數與製造商提供的功率係數有所誤差時仍有不錯的輸出結果。

In this thesis, we discussed the controller of the wind turbine with uncertainty: power coefficient, the impact on the overall Wind Energy Conversion System (WECS). Because the power coefficient which obtained through experiment or simulation is mainly supplied by the manufacturer. If the weather changes or the mechanical aging, it may produce an error between the actual model and the model that the manufacturer supplied, resulting in the performance of the wind turbine can’t meet expectation. In order to improve this problem, we use perturbation and observation (P&O) to design the reference of the rotor speed ω_ref in maximum power point tracking (MPPT), and use PI controller in power regulation (PR). We eliminate the nonlinear terms of the equation of the flux through feedback linearization, thereby obtain a control equations of rotor voltage, and use the equations to control the wind turbine. Finally, we compared the proposed method with existing controller through simulations. It is shown that the proposed method have a good performance when the parameters of the power coefficient changes.