對於資料中心和通訊方面的應用來說，電源供應器的功率從幾百瓦特到幾千
瓦特的應用都有，其中電源供應器由前級的功率因數修正器和後級的直流直流-轉
換器所組成。 例如對於通訊方面的應用來說，電源供應器前級的功率因數修正器的
輸入電壓通常為 360V 到 400V 之間，後級直流-直流轉換器的輸出電壓為 48V 到
60V 之間。對於高功率的應用來說，全橋相移拓樸經常被使用在大電流輸出的條件
下，但是該拓樸仍然有達成零電壓切換的負載範圍過小以及輸出端整流元件電壓應
力過高等缺點，這些缺點會限制該電路無法操作在數百萬赫茲的切換頻率。本篇論
文提出了使用兩個鉗位二極體的 Tr-lead 型全橋相移拓樸，解決上述提到無法操作
在數百萬赫茲操作頻率的問題。由於整流二極體的寄生電容與反向恢復特性會嚴重
影響轉換器操作在高頻下的表現，本論文會針對上述的狀況和傳統全橋相移拓樸與
Tr-lead 型全橋相移拓樸進行細節分析。本論文提出的解決反向恢復特性的方法是
使用增強型寬能隙元件氮化鎵 取代傳統的矽元件。最後本論文實做了一操作頻率
為 1MHz、輸出功率為 480W 的 Tr-lead 型全橋相移電路，並且由實驗結果可以得
到，該電路可以在寬負載範圍下達到零電壓切換和操作在數百萬赫茲操作頻率。此
電路在滿載的時候達到最高轉換效率 93%

The Power Supply Unit (PSU) for data center and telecommunication application
typically handles from few hundreds Watt to few kilo Watts, that is composed of Power
Factor Corrector (PFC) stage and frond-end DC-DC stage. For application such as
telecommunication, the output voltage range is typically regulated at 48-60V from the 360- 400V input voltage source of PFC circuit. For high power application, the full bridge topologies, i.e. phase shifted full bridge (PSFB) converters are mostly used due to ability of carrying high current. The conventional PSFB converters have the drawbacks of narrow zero voltage switching (ZVS) operating range and high voltage stresses on the output rectifiers, which limit the operating of converter in MHertz switching frequencies. In this dissertation, the Tr-lead type PSFB converter employing two clamping diodes to overcome abovementioned issues is presented. The parasitic capacitor and reverse recovery characteristics of the output rectifiers that severely effect the performance of converter in high switching frequencies are discussed, together with the detailed analysis of both conventional and proposed converter. The solution of using enhanced mode Gallium Nitride wide band gap devices is introduced in order to overcome the drawback of Silicon based devices. Finally, a 480W 1MHz switching frequency prototype is built up and tested in laboratory. The experimental results show the ZVS achievement of switches in the wide range of load conditions, featuring the capability of operating in MHertz frequencies of this converter. The achieved peak efficiency of converter is up to 93% at full load condition

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