電力電子轉換器為交流與直流電源兩者之間的轉換，最常見有三大類基本轉換器：交流對直流(AC/DC) 轉換器、直流對直流(DC/DC)轉換器、及直流對交流(DC/AC)轉換器。由於電力公司所送出的是交流電源，而電子電路大多使用直流電源，幾乎在家中每個電子產品都用到交流對直流(AC/DC)轉換器，再經由降壓式直流對直流(DC/DC)轉換器將直流電源轉換到另一直流準位， 而單級式AC/DC轉換器結合功因修正與降壓電路為一體， 因此可減少產品成本、尺寸， 改善能源效率。 此論文裏，我們對單級降壓式功因修正轉換器，以Matlab/Simulink 及Saber simulator 軟體進行轉換器電路的特性模擬， 而經由對電路特性的了解， 以及對電路方塊相關的數學式子推導後，說明我們所提出電路架構與一般降壓式功因修正轉換器電路，在輸入電壓變動時，其電路系統總功率維持在一定值，不會因為系統的瞬時功率提升，而引起電器產品的總功率耗損，也因此可以達到節能省碳的目的。最後說明所提出新的輸入電流控制系統， 改善了降壓式功因修正轉換器的諧波失真，並且使得輸入電流與輸入電壓同相位，達到單一功率因數與電路輸出穩壓的目的。 The power electronic converter is an interface between alternating current (AC)and direct current (DC). Generally, it can be classified into three categories: AC/DC converter, DC/DC converter, and DC/AC converter. Since the power is transmitted with AC fashion, most home-electronic products should translate it to DC by two-stage solution, which consists of AC/DC converter and buck converter. In this thesis, a single-stage solution, which integrates power factor correction (PFC) circuit and buck converter, is proposed to save cost and improve power efficiency in comparison with two-stage solution. The feature of our proposed circuit can make the total power consumption identical while the input AC voltage is changed. As a result,the power consumption of home-electronic products can be reduced whether the instantaneous power increases. In addition, the behavior of proposed circuit is presented with mathematical analysis, and its function is verified by the system simulation software, Matlab/Simulink and Saber simulator. Consequently, based on our proposed circuit, the harmonic distortion of power-factor buck converter is greatly reduced, and zero phase different between input current and voltage is achieved. Furthermore, the power factor is almost approximated to 1, and the regulation of output voltage is also maintained.
