感應馬達間接式磁場導向控制法則之應用與延製

Abstract

本論文提出改良型磁場導向控制法則作為感應馬達轉速控制之用，磁場導向控制法則是利用座標轉換的觀念將馬達三相分量解耦為d-q軸的兩相分量，再控制轉子磁場使其與同步旋轉座標標齊，如此一來即可對馬達做精確的解耦控制，然而一般PID控制在速度追隨上因為馬達參數變動而不易作出適當補償，故而我們提出改良型模糊控制的方法，我們將補償函數附加於電流電壓迴路中使其成為主要補償量，並將原先迴路中的PID控制器以模糊邏輯控制器來取代，如此一來較易提昇速度追隨能力，並能對馬達參數變動情況作出適度反應，此外，由於我們需要快速精確的追隨速度控制命令，所以我們摒棄傳統的正弦脈寬調變方式而改採空間向量脈寬調變的方式來組成輸出電壓並使用對稱型空間向量脈寬調變法則使其有效降低諧波成份與提昇直流鏈電壓使用率並可更快速的組成我們所需要的電壓。最後藉由模擬及實驗結果驗證本理論的可行性。

This thesis presents a modified field-oriented control method for speed-control of induction motors. The three phase quantities of motor is first transformed into d-q coordinate quantities. The rotor electro magnetic field is then aligned with synchronous rotating frame. A modified fuzzy control scheme is adopted to replace traditional PID controller for speed tracking. This is achieved by adding a compensation function on original current/volt loop. From numerical simulations, the performance of robustness with respect to parameter variation were found to be enhanced. In order to decrease reaction time for speed command, SVPWM method is employed to compose desired voltage. The symmetrical SVPWM method is known to be able to reduce harmonics, efficiently improve DC bus utility and easily compose desired voltage. Finally, numerical simulation and expeimental results are given to demonstrate the main results.