提高電源轉換器之切換頻率可提升功率密度，但相對地會造成很大的切換損失，GaN E-HEMT具有很快的切換速度，適合電源轉換器高頻切換應用。本論文使用GaN E-HEMT功率開關於全橋諧振轉換器，此架構具有零電壓切換之特性，使轉換器工作於高切換頻率提升功率密度。本論文首先介紹GaN E-HEMT之特性，分析全橋諧振轉換器動作原理，並探討GaN E-HEMT閘極驅動電路之要求。最後以數位訊號處理器TMS320F28335作為主架構控制器，實作一切換頻率為1 MHz之全橋諧振轉換器，輸入電壓為380 ~ 420 V、輸出為48 V / 960 W，並以同步整流提升系統效率，實驗結果顯示最高效率於50%負載時為90.5%。

Increasing the switching frequency of the power converters can increase the power density, but it will cause more switching losses. Gallium nitride enhancement mode high electron mobility transistors (GaN E-HEMT) have fast switching speed characteristic, it is suitable for high switching frequency applications. In this thesis, GaN E-HEMT are used as the main switches of the full-bridge resonant converter which has the soft-switching technology, so it can be operated at high switching frequency to increase the power density. The characteristics of GaN E-HEMT are investigated, and the operating principles of full-bridge resonant converter are analyzed, and the design considerations of gate drive circuits are discussed in this thesis. The digital signal processor, TMS320F28335, is used as the main controller. Finally, an experimental prototype is built with the switching frequency 1 MHz, the input voltage 380-420 V, the output voltage 48 V, and the rated power 960 W. System efficiency can be further improved by synchronous rectifiers technology, and the highest efficiency is 90.5 % at 50 % load.

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