高壓直流轉換器現今已廣泛使用於許多高壓應用場合，然而現有二倍壓轉換器受限於升壓比不足，較不適用於需更高電壓輸出之應用。若採用多級串接之方式以提高電壓增益比，但如此將使其整體轉換效率低落且增加電路複雜度。基於上述理由，本論文之主要目的即為提出一新型高效率四倍壓直流轉換器。
本論文的主要貢獻有三點。首先，本文提出一單級新型無變壓器型四倍壓直流轉換器，該新型轉換器具有高升壓比、低開關跨壓與高效率等特點。此外，該新型轉換器不需添加額外控制電路，即具有自動均流之優點。第二點貢獻則是針對新型轉換器直流電路特性進行分析，且進一步推導出小訊號數學模型。第三點貢獻則依據理論分析的結果，實際製作一輸入電壓25V、輸出電壓400V以及輸出功率400W之雛型系統以驗證新型轉換器的可行性。經由電路模擬與實測結果顯示本論文所研製之新型轉換器，其主動開關與二極體跨壓分別為輸出電壓的四分之一與二分之一，其電源轉換效率於120W至400W的負載情況下均為93%以上，負載在120W時效率最高可達到95%，以此驗證該新型轉換器之可行性與優越性。最後，本文亦提出一具隔離特性之四倍壓轉換器。

High voltage DC converters are widely used in various applications to provide a high output DC voltage. However, the existing voltage doubler is not sufficient for some much higher voltage applications. Although, one can cascade more stages to achieve the desired voltage level, however, the resulting complex topology will result in less efficiency and reliability. Hence, the major motivation of this thesis is to propose a high efficiency voltage quadrupler DC converter.
In fact, the major contributions of this thesis may be summarized as follows. First, a single stage transformerless voltage quadrupler DC converter is proposed for achieving much higher voltage gain, less voltage stress of switches and higher efficiency. In addition, the proposed converter possesses automatic current sharing capability without adding any extra component. Second, mathematical model of the proposed converter is derived and fundamental characteristics of the new converter are analyzed. Third, a 400W rating prototype with 25V input and 400V output is constructed for verifying the feasibility of the prototype converter. It is seen that the voltage stress of the active switches and the diodes are equal to quarter and half of the output voltage respectively. The resulting efficiency can be maintained above 93% as the load is varied from 120W to 400W, and the highest efficiency of 95% is achieved at 120W. Both simulation and experimental results indeed verify the effectiveness of the proposed converter. Finally, the extended isolated version of proposed quadrupler converter is also presented in this thesis.

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