在電動汽車電池系統應用中，需要寬範圍的輔助電源模組，將高壓動力電池組轉換至低壓輔助電池。本論文以碳化矽功率元件實現寬範圍的兩級轉換器，第一級為升壓轉換器，第二級為全橋諧振轉換器。控制法為根據系統的輸出電壓範圍，將第一級轉換器透過脈寬調變控制以設計相對應的輸出電壓範圍，使第二級轉換器操作於接近串聯諧振頻率之定頻控制，因此可以加大磁化電感以減少循環電流，加上二次側同步整流技術，以達到整體系統高效率。論文首先研究了全橋諧振轉換器的基本原理與動作原理，並分析兩級轉換器的理論損耗。最後，以數位訊號處理 TMS320F28335作為主架構控制器，實作了輸入電壓220-450 V、輸出電壓9-16 V、額定功率為2.5 kW之電路。由實驗結果得知，在輸入電壓為450 V和輸出電壓為9 V，20%負載時的條件下，系統最高效率為97.74%。並且，理論分析之效率趨勢與系統量測之效率相近，在全載條件下兩者的誤差百分比皆接近於1%。

In the application of electric vehicle battery systems, an auxiliary power module with wide range is required to convert the high-voltage battery pack to the low-voltage auxiliary battery. A two-stage converter with wide-range is implemented with silicon carbide power devices in this thesis. The first stage is a boost converter and the second stage is a full-bridge resonant converter. According to the output voltage range of the system, the corresponding output voltage range through pulse width modulation control is designed for the first-stage converter. In this way, the second-stage converter can be operated through near series resonant frequency control, the magnetizing inductance can be designed to be large to reduce circulating current, and with the synchronous rectification technology of the secondary side, the overall system efficiency can be improved. In this thesis, the fundamental and operating principles of the full-bridge resonant converter are studied first. In addition, theoretical losses of the two stage converters are analyzed. Finally, a prototype with input voltage (VH) 220-450 V, output voltage (VL) 9-16 V, and rated power 2.5 kW is built with a digital signal processor TMS320F28335. As the experimental results shown, the maximum efficiency of the system is 97.74% with VH = 450 V and VL = 9 V at 20% load condition. Moreover, the efficiency trend of the theoretical analysis is similar to that of the measurement. The error percentage of both are close to 1% under all load conditions.

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