再生能源在生活中扮演的角色越來越重要，然而在電能轉換上，再生能源的輸出電壓大約在35 – 60-V之間，需要一升壓轉型換器將其電壓提升至適合的電壓電位以併入市電。理論上，傳統的昇壓型轉換器可透過較大的開關責任週期將低電壓升至較高的電壓，但傳統昇壓型轉換器存在許多問題，尤其是線路上的等效串聯電阻和二極體的逆向回覆電流導致電壓無法升至較高的電壓電位，並且效率較低。
本論文提出一具電壓箝位高昇壓比直流-直流轉換器。本文提出之架構係利用三繞組耦合電感結合倍壓電路以提高昇壓比，並避免過大的責任週期。所提轉換器之激磁電感操作於連續導通模式，使其輸入電流保持連續不降為零，以減少電流漣波，其較低的電流漣波可減少使用之輸入濾波電解電容值，並增加其壽命與可靠度。本架構加上一箝位電容，使主動開關上跨壓可有效的降低。此外，所提電路耦合電感之漏電感能量不但可被回收至輸出負載，主動開關上開路瞬間漏電感能量所造成的突波電壓亦可被箝制；因主動開關所需電壓應力減少，故可採用低電壓規格及低導通電阻之主動開關，可進一步減少其切換瞬間所形成之切換損失及導通損失，輸出二極體的逆向回覆電流亦可有效的被抑制，使轉換器損失降低。
本論文說明所提出的直流-直流昇壓轉換器分別透過電腦模擬和實作驗證所提電路的可行性。在硬體電路方面，成功實現一功率200 W，輸入電壓42 V和輸出電壓400 V之實體電路。本論文將討論其電路操作原理、電路穩態分析以及元件電壓應力分析，以驗證所提電路的可行性。

Renewable energy is becoming more and more important, but the output voltage ranges of renewable energy between 35 and 60 V, should be converted further to adapt to load demand. Therefore, a high step-up voltage conversion ratio DC-DC converter is required to boost the output voltage of renewable energy resources. Theoretically, a conventional DC-DC Boost converter can achieve such a high step-up output voltage with an extreme duty ratio. But the voltage conversion ratio and the efficiency are limited by equivalent series resistance (ESR), switching loss, and reverse-recovery problems.
A high step-up DC-DC converter with three-winding coupled inductor and clamp capacitor is proposed in the thesis. The proposed converter in the thesis utilizes a three-winding coupled inductor and voltage doubler to increase voltage conversion ratio without an extreme duty ratio. The input current is operated at CCM, therefore, the input current ripple can be reduced and the lifetime and reliability of the input filter can be increased accordingly. Clamp capacitor in the proposed converter is to clamp and reduce the voltage stress of active switch. The power switch with low power-rating and low on-resistance can thus be utilized to reduce switching and conduction losses. In the proposed circuit, the leakage energy can also be recycled to the output capacitor at the load terminal and the reverse recovery problem of output diode can be alleviated to increase the efficiency.
The proposed converter is verified via computer simulations and experiments. On the hardware implementation, a 200 W prototype circuit, having input voltage of 42 V and output voltage of 400 V, is used to verify the feasibility of the proposed converter with operation principles, steady-state analyses, and voltage stress on each device discussed in the thesis.

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