動態電壓補償器控制系統的設計與模擬

Abstract

本論文探討動態電壓補償器(dynamic voltage restorer)使用若干種線性控制以及非線性控制時，對於電壓驟降的補償效果。為了改善現有控制方式的響應速度以及控制精度，本論文在線性控制的部分設計了帶積分的LQR 狀態回授控制；在非線性控制的部分則使用時變順滑面的順滑模態控制(sliding mode control)，並且設計了時變順滑面變化的規則。最後透過數值模擬的方式與現有的控制系統比較，證明所提出的兩種控制系統應用於動態電壓補償器，在面對不同型式電壓驟降時皆有不錯的補償效果。

In this thesis, the performance of a dynamic voltage restorer against voltage dips using several control systems, including linear and nonlinear control, is studied. Two methods are proposed to improve the system tracking ability compared to traditional PI control and sliding mode control. The first method designs a state feedback controller through LQR multivariable control techniques to enhance steady state accuracy. The second method designs a sliding mode controller using a time-varying sliding surface in order to reduce the total harmonic distortion in the sensitive load side. The time-varying sliding surface can be determined by introducing boundary control and some other design principles. Comparisons between the above mentioned control techniques are investigated through computer simulations. It is shown that the proposed methods provide either faster response or higher compensation accuracy. Simulation results under symmetrical and unsymmetrical voltage dip are also presented.