本文提出一具非線性轉換比之雙變壓器主動箝位零電壓切換順向式轉換器，其架構以主動箝位零電壓切換順向式轉換器為基礎，利用雙變壓器共生之方式將兩組單晶電源轉換器組合。此架構之優點為變壓器與輸出整流二極體在選擇上僅需以一半的負載功率作為考量；另外轉換器亦僅需兩個切換開關，因而可降低轉換器控制複雜度，且兩組切換開關皆操作於零電壓切換，可提高轉換器效率。本文透過次級側整流架構的改變，可使電路同時有寬輸入電壓範圍與高降壓比的特性，並讓轉換器能有更高的開關利用率。本文將分析與討論電路之動作原理及設計，並實作一台輸入直流電壓130~230 V、輸出24 V/8 A之具非線性轉換比雙變壓器主動箝位順向式轉換器，以驗證理論分析與實測結果。

This thesis presents a two-transformer active-clamping zero-voltage-switching (ZVS) forward converter with non-linear conversion ratio. The proposed topology is mainly composed of two active-clamping converters. The advantage of this topology is that the output power can be shared by two transformers. Therefore, the stresses of the output rectifier can be decreased. Only two switches are required. The circuit complexity is thus reduced. The leakage inductor of the transformer or an additional resonant inductor is employed to achieve ZVS during the dead times, and therefore the converter efficiency is improved. By changing circuit architecture of the secondary side, the presented converter is more suitable for wide input voltage range, high step-down ratio feature and higher switch utilization. The operation principles and design considerations of the proposed converter are analyzed and discussed in detail. The input voltage is from 130 V to 230 V, the output voltage is 24 V, and the output current is 8 A. Theoretical analyses are verified with the experimental results.

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