本論文主要研製一種混合切換主動箝位返馳式轉換器，所提出混合切換技術可增加功率開關之零電壓切換範圍。本文將氮化鎵高電子遷移率電晶體使用在混合切換主動箝位返馳式轉換器中，藉以提高切換頻率，降低功率損耗。二次側方面採用同步整流技術，以減少導通損耗。再者以平板變壓器取代傳統繞線架繞製的變壓器。本論文最終實現及測試一台65 W/ 1 MHz，輸入電壓90 VAC~264 VAC，輸出電壓19.5 V的雛型轉換器，實驗結果驗證電路可行性，效率最高可達90 %。

This thesis aims to study a hybrid-switching active-clamped flyback converter. The propsed hybrid-switching technique can increase the range of zero-voltage switching. GaN HEMT transistors are also applied in this study to reduce the switching losses at high switching frequency operation. Synchronous rectifier is designed on the secondary side to minimize the conduction losses resulted from the high output current. In addition, a planar transformer is designed to replace the conventional transformer with winding bobbin. A 65 W/ 1MHz prototype converter is implemented and tested under 90 VAC～264 VAC input and 19.5 V output. The experimental results are shown to verify the feasibility. The measured efficiency can be up to 90 %.

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