Bang-Bang順滑控制在切換式電源轉換器之設計

Abstract

本論文利用bang-bang順滑控制來設計降壓式直流轉換電路之控制器，由於開關元件只操作在開和關兩個狀態，加上順滑迫近區間會因為選擇不同的順滑函數而改變，導致順滑行為無法全域地存在狀態空間中，並產生不同的切換行為。本論文會在相平面中詳盡地分析系統的狀態軌跡，同時經由實驗來驗證。此外，實務設計時所會面對的問題也將同時考量，並且加入週期性的斜坡函數來達到固定的切換頻率。最後，本論文將利用bang-bang順滑控制來設計某一類切換系統的控制器，同時提出存在穩定順滑行為的兩個條件，由於推導出的控制法則包含兩個切換函數，因此會產生複雜的切換行為，在本論文中也將清楚的描述這些切換行為，並更進一步探討該控制器對於系統中存在不確定模式的強健性，最後經由數值模擬來呈現。

In this dissertation, the bang-bang sliding mode control is proposed to design the switching controller for a buck DC-DC converter. Normally, the on and off states of the switching device is modeled as an input switching between 1 and 0, and the reaching-and-sliding (RAS) regions are crucially related to the parameters of the sliding function. As a result, the sliding motions may not globally exist and different switching behaviors may be generated. With the bang-bang sliding mode control, the system trajectories of a buck DC-DC converter will clearly depicted in the phase plane and experimental results will be given for verifications. Besides, some considerations about the practical implementation are also included and a periodic ramp signal is added into the controller to achieve constant switching frequency. Then, the bang-bang sliding mode control is also adopted to design the switching controller for a class of switched systems. Two sufficient conditions to guarantee the existence of stable sliding motions will be given and the complex switching behaviors resulting from two switching functions will be clearly described. Moreover, the robustness of this switching controller to model uncertainties will be discussed. Finally, numerical simulations are given for demonstrations.