有別於單級單相交流/高壓直流昇壓型轉換器之功率開關操作於硬式切換，本文提出於此轉換器中加入一輔助電路，使功率開關達成軟性切換之功能，改善開關之切換特性，文中將說明此架構之操作原理，並說明電路元件的設計法則。本文提出之轉換器使用功率因數修正技術，以改善輸入電源電流品質。本文提出之系統，僅需簡單的改變常見的功率因數修正方法之PWM訊號便可使用於本結構上。本文使用一般常見之功率因數控制IC，將產生之PWM訊號加上簡單的邏輯運算後，用以控制主開關及輔助開關。本文實作一輸出500瓦1200伏特之系統電路，以實驗結果驗證此轉換器之可行性。

This paper proposes a soft-switching technique applying to a single-stage single-phase ac to high voltage dc converter based on Cockcroft-Walton (CW) voltage multiplier circuit. Originally operating under hard-switching, the proposed converter improves switching characteristics by adding an auxiliary circuit for achieving soft-switching. The circuit operation principle of the proposed converter is presented in this paper. The design consideration for determining the values of circuit components used in the implementation is driven as well. For improving the line condition, power factor correction is applied to the proposed converter. Some conventional PFC control methods can be easily adapted to the proposed converter with few modifications. For convenience, this paper employs a commercial PFC IC to implement the controller for the proposed converter. The PWM signal generated form the PFC IC is modified by a simple digital circuit and then sends to the main and auxiliary switches in the power stage. A 500W/1200V prototype is built for test, measurement and evaluation. Finally, the experimental results demonstrate the validity of the proposed converter.

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