改良式之雙饋式感應風力發電機之磁通估測法

Abstract

本論文主要目的在研究雙饋式感應風力發電機之磁通估測改善法，使轉子側變流器能有效控制發電機達到最大功率輸出及損失最小化。由於純積分器在實際應用上會有初值問題及直流成分輸入等問題，而一階低通濾波器則會造成估測之磁通相位及大小的誤差，故本文提出了三種演算法以改善磁通估測的效能。 首先針對風力機及雙饋式感應發電機之特性進行分析，說明如何利用定子磁通導向達到解耦合控制，再從推導出的數學公式得知磁通估測的大小及角度對轉子側變流器控制的影響，最後分析磁通估測所遇到的問題及利用補償架構及正交偵測器改善估測之準確性，並以MATLABR模擬驗證其效能。

The main purpose of this thesis is to search for methods to improve the flux estimation of a doubly-fed induction generator to allow the rotor-side converter to control effectively the generator to reach its maximum power output and minimize the power loss. Due to the problems such as initial value and DC component input of the pure integrator occurred in practical application and the deviation of the estimated flux phase and magnitude caused by the first-order low- pass filter, three algorithms were studied in this thesis to improve the efficiency of flux estimation. First, features of wind turbine and doubly-fed induction generator were described and the way to reach decoupled real and reactive power control utilizing stator-flux oriented synchronous reference frame was explained. Then, from the deduced mathematical formula, the effects of the magnitude and phase angle of the magnetic flux estimation on the rotor-side converter control were studied. The problems associated with the existing flux estimation were identified, an alternative algorithm with the compensation structure and the quadrature detector was studied to improve the accuracy of flux estimation. Finally, MATLAB○R was employed to simulate and verify the performance of the flux estimation algorithms.