應用於海水淡化之電壓雙象限升降壓轉換器及其能量回收系統

Abstract

在非隔離型電源轉換器的應用中，升降壓轉換器有電路架構簡單，並可兼具升壓及降壓功能之特性，進階的電壓雙象限升降壓轉換器更可調整輸出端的電壓極性。在升降壓轉換器的眾多應用中，其中之一是可利用經過設計的能量回收系統，使海水淡化中之電容去離子化法達成能量回收再利用的節能目的。在本論文中以電壓雙象限升降壓直流轉換器實現一應用於海水淡化電容去離子化法的節能系統，透過將直流轉換器的輸出端做正反極性的週期性轉換以得到淡化模組上電壓的交替變換，進而提升實際海水淡化上的效率。此電壓雙象限升降壓直流轉換器架構簡單，不需要複雜的設計即可達成變換輸出電壓極性的目的，並且在控制上也十分簡易，可有效達成所需之控制功能。本文在提出電路架構後，以簡單的模型分析決定所使用的元件參數值，並以模擬軟體進行模擬加以驗證，最後進行實驗並量測電路輸出來證明電路的功能及能量轉換效率，確認此電路能達到電壓雙象限的電壓轉換效果。

In non-isolated power converter applications, buck-boost converters have merits like simple circuit topology and output voltage lower or higher than the input voltage. Advanced two-quadrant, up-down voltage converters even have the ability to change output voltage polarity. One of many applications is to save energy by using a designed energy recovery system in the Capacitive De-Ionization (CDI) seawater desalination system. In this thesis, we realize an energy recovery system applied to a CDI desalination system by using a two-quadrant, up-down voltage converter. Through changing the output voltage polarity of DC/DC converter periodically, we have the voltage polarity on the desalination modules of alternate positive and negative and improve desalination efficiency in reality. The two-quadrant, up-down voltage converter is simple in its structure and control. No complex design is required. After circuit architecture proposed, we analyze it with a simple model to determine parameters of devices used in circuit. Then the circuit is simulated to verify the former analysis. Finally, an experimental circuit is implemented to guarantee the work function and measure the energy conversion efficiency.