電能轉換中，如輸出電壓較低時，需要一升壓轉換器提升其電壓，因此發展許多升壓轉換技術，但因許多轉換器之輸入電流為脈動型態，大電流漣波會造成太陽能電池輸出功率無法保持運轉於最大輸出功率點、導致其平均輸出功率減少等問題，且對燃料電池應用而言，常造成擴散層之衝擊，影響其壽命。是故，電流饋入型態高升壓型轉換器較適合於再生能源發電，特別是於燃料電池的應用。
本論文利用SEPIC直流轉換器以及串接轉換器架構，提出一電流饋入高昇壓直流轉換器。所提轉換器第一個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。所使用之第二個電感則應用耦合電感器，選擇適當的匝數比以達成高電壓轉換比並避免過大的責任週期。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外，且主動開關上開路瞬間漏電感能量所造成的突波電壓可被箝制，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。另外，同步整流技術亦應用於本電路，其取代整流二極體以減少其導通損失。
本論文說明所提出的直流-直流昇壓轉換器之電路操作原理、電路穩態分析以及元件電壓應力分析，並以模擬與實驗結果驗證所提電路的可行性與有效性。

High step-up techniques have been explored and developed for boost converter applications. However, many of the converters have the problem of high pulsating input currents from the power source, which often is a disturbance on the DC output of a renewable power source, like fuel cells or solar PV cells. Concerned is the significant impact on fuel cell diffusion layer or the output power of solar PV cells. For this reason, high step-up of current-fed configuration converter is considered more suitable for renewable source generation system, especially for the fuel cells.
Based on SEPIC converter and cascade topology, this thesis proposes a current-fed high voltage step-up DC-DC converter. The first inductor of the proposed converter is operated in continuous conduction mode, which has lower pulsating input current and thus reduced current ripple. The reduced current ripple can minimize the input electrolytic capacitor needed and extend its life-time as well as reliability. The second inductor employed in the proposed circuit is a coupled inductor to achieve much higher voltage conversion ratio and avoid operation at extreme duty ratio via a proper turn ratio. In addition to, the voltage spike on the main switch can being clamped, the leakage inductance of the coupled inductor is designed to be recycled to output load. Therefore, with reduced voltage stress on the power switch, its power-rating and on resistance can be lower to further decrease both switching and conduction losses. Moreover, synchronous rectifier is applied into the front-end of the proposed converter to further decrease conduction losses.
The operation principles and analyses of the steady-state and voltage stress on each semiconductor device are presented in this thesis. Feasibility and effectiveness of the proposed circuit are verified via computer simulations and practical experiments.

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