應用於光伏系統之具零電壓切換隔離型模組整合轉換器

A ZVS Isolated Module-Integrated Converter for Photovoltaic Systems

王顥霖(Hao-Lin Wang)

指導教授 ： 潘晴財 ； 吳財福

國立清華大學/電機資訊學院/電機工程學系/碩士(2013年)

摘要

有鑑於全球氣候變遷、生態環境破壞及地球能源的迅速耗竭等問題，如何有效地運用再生能源已成為全球關注的議題。在眾多的再生能源中，光伏系統相較於其他發電系統在環境上與經濟效益上擁有較多的優勢。由於模組整合轉換器不僅可以克服遮蔽效應對太陽光伏模組所帶來的影響，同時也擁有較高的安全性，因此成為近年來熱門的研究課題。本論文之主要目的即為提出一應用於光伏系統之具零電壓切換隔離型模組整合轉換器以有效地利用太陽能資源。

　　本論文之主要貢獻可分述如下：首先為第一點貢獻，本論文提出一具零電壓切換之新隔離型模組整合轉換器。此新模組整合轉換器電路架構乃基於隔離型SEPIC轉換器之延伸，再串接一低頻全橋反流器而成。藉由前級所加入之主動箝位電路可以使主開關與輔助開關皆具零電壓柔性切換之能力，同時有效地消減輸出二極體之反向回復電流成分。第二點貢獻，此新模組整合轉換器只需藉由簡單的控制方法，即可輸出一具整流之正弦波波形電壓至擬直流鏈之交流電容上。由於本文前級電路採兩相交錯式控制，因此可降低輸入電流漣波對電路所造成之電磁干擾；此外，此新模組整合轉換器主動開關之責任週期可全範圍自由調整，因此擁有較寬廣的可應用之輸入與輸出電壓範圍。第三點貢獻，依據理論分析結果，實際製作一額定25V直流輸入、110V均方根值交流輸出，及額定輸出功率為150W之雛型系統，以驗證本文所提新模組整合轉換器之可行性。經由實驗結果顯示，本論文所研製之新模組整合轉換器之轉換效率於40W至150W的負載情況下均在86.7%以上，在40W負載下可達最高效率92.4%。

關鍵字

交流模組 ； 模組整合轉換器 ； 零電壓切換 ； 擬直流鏈

並列摘要

In view of the problems of global climate change, environmental impact and shortage of fossil fuels, exploring the use of renewable energy has drawn a lot of attention internationally. Among a variety of renewable energy technologies, photovoltaic technology has more environmental and economic benefits than the others. However, existing DC converters still face the partial shading effects bottleneck problem. Recently, module-integrated converters (MIC) have become a hot research topic as a means for overcoming the partial shading effects of photovoltaic systems and achieving high safety. Hence, in this thesis, to further improve the energy yield, emphasis is placed on the development of a novel ZVS isolated module-integrated converter for photovoltaic systems.
Major contributions of this thesis can be summarized as follows. First, a novel MIC with pseudo dc-link and galvanic isolation is proposed. It consists of an isolated SEPIC converter cascaded with a full-bridge inverter operating under line frequency to achieve high efficiency. Furthermore, active-clamped circuits are added to the isolated SEPIC converter to achieve zero voltage switching and alleviate the reverse-recovery current of the output diodes. Secondly, a simple control strategy is proposed to generate a rectified sine waveform voltage at the dc-link capacitors. Also, to reduce input current ripple, an interleaved control strategy is adopted. It has been found that the duty ratio of the active switches can be operated in full range to achieve wider output voltage control range. Finally, a prototype with 25 V input, 110 Vrms output and 150 W rating has been constructed for verifying the feasibility of the proposed MIC. Experimental results have shown that the overall efficiency of the MIC can be maintained above 86.7% as the load varies from 40 W to 150 W, and the highest efficiency of 92.4% has been achieved at 40W.

並列關鍵字

AC Module ； Module-integrated converter ； ZVS ； Pseudo dc-link

參考文獻

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[33] 吳建銘，降壓同步倍壓整流半橋轉換器之研究，國立成功大學電機工程學系碩士論文，民國九十三年。

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