由於近年來大量使用石化燃料造成自然環境破壞與溫室效應，世界各國開始提倡以再生能源取代石化燃料，在各種再生能源系統中，太陽光伏系統因為不需額外的機械部分，所以較吸引人們研究其相關技術。但此類系統皆為低電壓直流電源，應用上必須依靠高升壓比直流轉換器將其轉換為適合的電壓準位，以滿足後級反流器提供交流輸出或併聯市電，故本文即針對此需求提出一新型高升壓比直流轉換器，以作為此類能源應用之介面。
本論文主要貢獻茲分述如下。本文提出一新型具零電壓切換隔離型高升壓比直流轉換器，此轉換器具有高升壓比、零電壓切換、可模組化、漏感能量回收與開關責任週期可全範圍自由調整而具有寬廣的電壓調整範圍等特點。並利用交錯式切換的方式減少輸入電流連波。最後則依據理論分析的結果，並輔以電路模擬軟體，實際製作一輸入電壓 至 、輸出電壓 以及額定輸出功率 之雛型系統以驗證新型轉換器的可行性。經由實測結果顯示本論文所研製之新型轉換器其主動開關均具有零電壓切換之特性，可減少開關電氣應力及降低損失，其電源轉換效率於 輸入電壓時，輸出為 至 的負載情況下均達93.8%以上效率，而在 負載時可達到最高效率95.7%，實測結果確實可驗證本新型轉換器之可行性與優越性。

In recent years, due to the environment impact and shortage of fossil fuels, many countries around the world begin to promote using renewable energy rather actively. Among various renewable energy systems, photovoltaic (PV) systems which do not having any moving mechanic parts are perhaps most attractive. However, the output voltage of a PV module is rather low. For practical application, a high step-up dc converter is normally required for boosting to a higher voltage level for the following cascaded inverter. Hence, a novel high step-up isolated DC/DC converter as an interface for these PV energy systems is proposed in this thesis.
The major contributions of this thesis may be summarized as follows. A novel isolated high step-up DC/DC converter is first proposed for achieving much higher voltage gain as an interface. The special feature of this new converter lies in its zero voltage switching (ZVS) characteristic for reducing greatly the electric stress of the switches and the switching loss as well as the interleaved control to reduce the input current ripple. Also, it can be modularized and the duty ratio of the active switch can be operated in full range. Furthermore, a 200W rating prototype with 20V to 35V input and 400V output is constructed for verifying the feasibility of the prototype. The experimental results show that the resulting efficiency can be maintained above 93.8% as the load is varied from 40W to 200W, and the highest efficiency of 95.7% is achieved at 80W.

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