零電壓轉換昇壓型功因修正器設計與實現

Abstract

本論文主要在研製一個具有高功率因數、低諧波、高效率且可操作於高頻之零電壓切換昇壓型功因修正器。傳統藉由輔助開關的昇壓型脈寬調變零電壓轉換器雖然可以解決開關切換的問題，但是加入的輔助開關多採用硬式切換，因此輔助電路上的元件仍然產生切換損失。本文針對輔助開關採用零電壓轉換方式以降低輔助開關損失，讓所有的主動與被動開關元件皆操作在柔性切換狀態下，提高整體效率。論文詳細介紹及推導所提出的零電壓切換功率因數修正電路於各工作模式下之操作原理與等效電路，並且針對電路設計，提出了系統化的分析設計方法。所設計之功因修正器經由Ispice進行模擬分析，並實作完成一個切換頻率為200kHz輸出功率為3kW的零電壓切換功率因數修正電路，實驗結果證實此柔性開關技術確實可降低開關損失，並提高整體效率及降低EMI干擾。

This thesis presents the design and implementation of a zero-voltage-transition power factor correction (PFC) converter having high power factor, low harmonic line current, high efficiency, and high switching frequency. Conventional boost zero-voltage-transition with auxiliary switches can reduce switching loss, however, the hard switching of the auxiliary switches can significantly increase additional switching losses. Soft switching techniques can be applied to these auxiliary switches to reduce the switching losses. By using zero-voltage-transition techniques, a lossless snubber circuit has been developed to reduce the switching losses of the auxiliary switch. The operational principle and equivalent circuits of the proposed zero-voltage-transition converter are analyzed in detail. In addition, a systematic design procedure has been given to design the converter. Computer simulation using Ispice has been carried out in analyzing the proposed zero-voltage-transition soft-switching PFC scheme. A 3kW, 200kHz prototype of the boost zero-voltage-transition PFC converter has been constructed. Experimental results can verify the efficiency improvement and EMI reduction by the proposed soft-switching PFC scheme.