全橋相移式直流-直流轉換器因具有零電壓切換的特性，可以減少切換損失和高頻雜訊造成的干擾，進而可提高操作頻率、降低磁性元件體積和提升轉換器效率。由於本論文所研製轉換器的輸出規格為低電壓大電流，故變壓器次級側使用同步整流開關來代替蕭特基二極體，以減少傳導損失。此外本文分析變壓器初級側加入箝位二極體對電路的影響，以及寬能隙元件GaN FET實際應用於落後臂的開關，有效改善了落後臂在輕載時不易達成零電壓切換的問題。本文將討論電路之動作原理及設計，並實作一組輸入電壓390 V、輸出12 V/54 A之全橋相移式零電壓切換轉換器，以實測結果驗證理論分析。

A phase-shift full-bridge converter with zero-voltage-switching (ZVS) features can reduce the switching losses and high-frequency noises. Thus, the conversion efficiency can be effectively improved and the switching frequency can be raised to reduce the sizes of magnetic components. Since the output specifications of the studied converter are low voltage and high current, synchronous rectifiers are used instead of the Schottky diodes on the secondary side to reduce the conduction losses. In addition, the effects of the primary-side clamp diodes are analyzed. And wide-bandgap GaN FETs are applied for the lagging leg to achieve ZVS at light load. The operating principles and design considerations of the proposed converter are discussed in detail. A prototype phase-shift full-bridge converter has been implemented. The input voltage is 390 V, the output voltage is 12 V and the output current is 54 A. Theoretical analyses are verified with the experimental results.

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