直接轉矩控制在感應馬達上的應用

Abstract

直接轉矩控制是以轉矩與磁通量作為輸入命令的一種方法，經由控制器之運算可直接地求出符合命令所需之電壓向量。本論文將利用順滑模態控制技術，針對交流感應馬達模型設計一順滑模態控制器以直接控制轉子轉矩與磁通振幅平方值使其達到所期望之值。於此將選定一非線性之順滑平面，並設計出馬達定子之參考電壓，以使系統狀態軌跡能產生順滑模態之行為，以達控制目的。 而由於感應馬達實際之轉子磁通難以估測，因此使用一降階磁通觀測器以估測其值。此外，利用適應控制中的方法、MRAC( Model Reference Adaptive Control )法則設計一MRAC位置控制器做為外部迴路以達成轉子之角度控制，並產生參考轉矩至順滑模態控制器。 在本論文中將以C語言建立模擬架構以進行電腦模擬。並以個人電腦為基礎，建構兩種實驗系統：第一種是由電腦配合週邊介面卡建置而成(PC-based)。第二種是由電腦配合DSP數位控制板建置而成(PC+DSP)。經由實驗結果驗證理論之可行性，以及軟體與硬體設計之正確性。

Direct Torque Control is to use torque and flux magnitude as input commands in the controller, which calculates the voltage vectors for the motor.In this thesis, we deal with the problem of using sliding mode technique to control and observe the states of an induction motor. We hope to directly regulate the rotor torque and the square of the rotor flux magnitude to the desired value. Nonlinear sliding surfaces are chosen and stator voltages are derived such that the state trajectories have a sliding mode behavior for the driving system to achieve the control objective. Because of the rotor fluxes are hard to measure in practice, the reduced order observer is used to estimate the rotor fluxes. Besides, the adaptive MRAC law will be also applied in position tracking control. The simulations of the control structure are implemented by C language. The experimental tools will be divided to two structures. One is built by PC and some interface cards. The other is built by PC and the DSP digital board. The results of simulations and experiments verify the validity and practice of this technique.