降壓式電流輸出及升壓式電壓輸出高功率因數交/直流轉換器

Abstract

隨著科技的快速發展帶給人類很多好處，相對的也帶來了一些越來越嚴重的問題，能源的問題是其中一個重要的問題。如何更有效率的來使用能源將會是一個重要的問題。而在交流/直流換流器中，如何提高功率因數(power factor)，是我們所要探討的課題。傳統整流器往往因電源側電流有很嚴重的諧波失真，所以沒辦法將功率因數提高，且輸出電壓很容易受負載的影響。本論文是採用主動式的功率因數修正，所提出的PFC電路是為兩目的而設計的:(1)降壓—電流輸出(2)昇壓—電壓輸出。其電感電流是在連續與不連續的邊界上，是一不固定頻率的功因修正器。並由實驗結果證明降壓—電流輸出在低瓦特數下具有高功率因數及升壓—電壓輸出的功率因數是趨近於1。

As the industrial technology has progressed rapidly in this era, the people really enjoy the products of high technology. However, the problem of energy shortage becomes more serious. Therefore, how to save the energy and use the energy in high efficiency are very important to us. To the ac-to-dc converter designer, high power factor is primary requirement. The traditional rectified power supply had very poor power factor since it produces plenty harmonic distortion of current in the ac power side. In this thesis, we use active circuits to improve the power factors of two kinds of converters: (1) voltage–step–down -and-current-output converter and (2) voltage-step-up-and-voltage-output converter. Since our circuit operates in a continuous-discontinuous condition mode, the switching frequency is a various one. Our experiment results have shown that we can have high power factor (more than 0.95) for the voltage -step-down-and-current-output converter and almost unity for voltage–step – up–and– voltage–output converter.