由於近年來電子產品在環保及省能方面的要求不斷的提高，如何減少電子產品所產生之能源損耗為目前電機電子人員研究的重要課題之一。本篇論文主要研製一個具低空載損耗的交流/直流電源轉換器，其中包括利用主動式功因修正電路及不對稱半橋轉換器搭配同步整流來提高轉換器在滿載時的功率因數及效率；而在空載狀態時，則將功因修正電路及同步整流電路的工作中斷以減少損耗，並使用脈波省略技術以降低不對稱半橋轉換器在空載時的損耗。最後實作完成一個滿載效率達88%，且空載待機時功率消耗約1W的電源轉換器作為理論分析的驗證。

The requirements of environmental protection and energy saving on electronic products are more and more stringent, and thus it is important for engineers to reduce the energy losses in the electronic products. This thesis studies and implements an AC/DC power converter with very low power losses during stand-by period. The main circuit topology includes power factor correction circuit and an asymmetrical half-bridge converter with synchronous rectifier to obtain high power factor and high efficiency at full load condition. The power consumption can be reduced at no load conduction by disable the power factor correction circuit and synchronous rectifier. In addition, the pulse skip scheme is used to reduce the loss in the asymmetrical half-bridge converter. Experimental results show that the converter can achieve 88% efficiency at full load condition. Also, the power losses can be reduced to about 1W during stand-by condition.

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