單級升壓-返馳-返馳並聯式轉換器之分析與實現

Abstract

為解決傳統返馳式轉換器之效率及功率因數無法提高之缺點，本論文研製出新型之單級升壓–返馳–返馳並聯式轉換器，主要可分為兩並聯路徑，一為升壓-返馳式轉換器，另一路徑為返馳式轉換器。其主要優點為升壓-返馳-返馳式轉換器可提高功率因數，當負載為動態負載時，返馳式轉換器可使輸出電壓變動更小，這二組並聯且共同輸出功率，以提高效率。經實驗測得，利用單級升壓–返馳–返馳並聯式轉換器與傳統的返馳式轉換器做比較，確實可以提高功率因數。本論文並利用MATHCAD數值計算軟體對單級升壓–返馳–返馳並聯式轉換器建立計算程式，並將計算結果之波形與實際實驗結果之波形比較。觀察電感與變壓器之三種工作模式，電流連續模式、電流臨界模式、電流不連續模式，在不同輸入電壓與不同輸出負載下對效率及功率因數之影響。

This paper proposes a single-stage boost-flyback-flyback parallel AC/DC converter with single-switch-two-output boost-flyback converter theory. One is the boost-flyback semi-stage that improves power factor and other one is flyback semi-stage that improves the regulation performance and increase efficiency. The proposed converter includes three operation modes- continuous current mode, boundary mode and discontinuous current mode. Various modes would result in various effect on efficiency and power factor under various input voltages and various output loads. The calculation result from MATHCAD and the experimental results demonstrate that the proposed boost-flyback-flyback converter yields higher efficiency and higher power factor than traditional flyback converter.