新式切換頻率調變控制技術之同步整流降壓型轉換器的研製

Design and Implementation of Synchronous Rectified Buck Converter with Novel Switching Frequency Modulation Control Technique

蘇暉發(Huei-Fa Su)

指導教授 ： 歐勝源

國立臺北科技大學/電資學院/電機工程系研究所/碩士(2010年)

摘要

本論文提出一種新式切換頻率調變控制技術，適用於主機板上的同步整流降壓型轉換器。此種變頻控制技術乃是當負載變輕時，將切換頻率調高，而負載變重時，則調低切換頻率。藉由此變頻控制技術不需額外增加輔助開關及其他的儲能元件即能實現零電壓切換並進而提升效率。為了避免導通損失過度增加，並使輸出電壓漣波能夠控制在規格內，有鑒於這些切換頻率限制等因素，在本控制方法中設定一負載電流之臨界點，當負載進一步增加時，則基於此臨界電流值而不再降低切換頻率。最後，本論文實際製作一組八相同步整流降壓型轉換器，並與傳統定頻在250kHz之控制技術相比較，藉以驗證所提切換頻率調變控制技術之良好性能。相較於傳統定頻切換技術，於八相同步整流降壓型轉換器加入所提之切換頻率調變控制技術後，其效率最高可改善約9%。

關鍵字

切換頻率調變 ； 相同步整流 ； 多相插敘式控制 ； 零電壓切換

並列摘要

A novel switching frequency modulation control technique of switching frequency for synchronous rectified buck converter used in such as motherboards is proposed in this paper. The switching frequency is modulated higher as loads more lightly and vice versa, so that the proposed scheme is also called variable-frequency control method. Zero voltage switching (ZVS) can be achieved to boost efficiency without additional auxiliary switches and any storage elements while frequency is modulated. To avoid conduction loss increase excessively and cause the output ripple under control and in view of the switching frequency being finite, the switching frequency will be fixed constant when the much more loading is added wherein the load threshold to fix switching frequency constant is found by experiments. Compared to conventional constant switching frequency techniques with 250kHz, experimental results derived from an eight-phase synchronous rectified buck converter show the proposed modulation technique is superior to the conventional one, the efficiency can be increased up to 9% for eight-phase synchronous rectified buck converter under various load conditions.

並列關鍵字

Switching frequency modulation ； Synchronous rectification ； Multiphase interleaved control ； Zero-voltage-switching

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