具同步整流之主動箝位順向式轉換器分析與研製

Analysis and Implementation of Active-Clamp Forward Converters with Synchronous Rectification

張煌章(Huang-chang Chang)

指導教授 ： 陳信助

崑山科技大學/工程學院/電機工程研究所/碩士(2007年)

https://doi.org/10.6828/KSU.2007.00056

摘要

本論文探討具有同步整流之低側主動箝位順向式轉換器(LACFC-SR)與高側主動箝位順向式轉換器(HACFC-SR)的電路分析、元件設計及系統研製。
轉換器的電路架構是在傳統的順向式電力轉換器加入了輔助開關和箝位電容，作為變壓器之磁通重置機制，不需要第三匝線圈。轉換器的特點包含：能有效疏導變壓器漏電感儲能，抑制電壓突波；能使主開關及輔助開關達到零電壓切換，降低開關之切換損失；同步整流器能在低壓大電流輸出時，降低導通損失，因此電路具有高電能轉換效率。在完成電路動作分析後，以IsSpice軟體作電路模擬，以驗證理論分析與實作之正確性。
為了達到輸出穩壓之目的，本文以狀態空間平均法推導電力轉換器之轉移函數，並以Agilent 35670A動態信號分析儀之量測結果作驗證，接著以古典控制理論設計穩壓控制器，以消除電壓源或負載變動對輸出電壓的影響。
在實驗室實作出輸入電壓為DC 30 ~ 60 V、滿載輸出為5 V/20 A，開關切換頻率為100 kHz之LACFC-SR及HACFC-SR轉換器系統各一組。由實作結果顯示，所有必v開關皆達到零電壓切換(ZVS)之性能，最高之電能轉換效率可達93.36%。無論在負載或電壓源變動的情況下，設計之控制器皆能使系統達到良好的穩壓效果。

關鍵字

順向式轉換器 ； 零電壓切換 ； 主動箝位 ； 同步整流

並列摘要

The circuit analysis, components design and system implementation of high-side and low-side active-clamp forward converters with synchronous rectification (HACFC-SR/LACFC-SR) are presented in this thesis.
The converters are composed by a conventional forward converter and an additional clamp circuit which is formed with an auxiliary switch and a clamp capacitor. With the help of clamp circuit, the flux in the transformer can be reset without tertiary winding in the converters. Moreover, the clamp circuit not only mends spike voltage produced by leakage inductor energy but also offers the main and auxiliary switches to achieve zero-voltage switching (ZVS) that reduces switching losses. Furthermore, the synchronous rectification (SR) is used to reduce conduction losses for the low voltage/high current application. After the circuit analysis, the IsSpice simulation is applied to verify the accuracy of theoretical analysis and experiment.
The converters transfer functions are derived by the state-space averaging approach. The analysis result is verified by the practical measurement of the dynamic signal analyzer Agilent 35670A. A controller is then designed to eliminate the effects of input voltage and load variations on the output voltage.
Finally, the prototypes of HACFC-SR and LACFC-SR with 30~60 V input and 5V/ 20A output have been implemented in the laboratory. The experiment results show that all switches can achieve ZVS operation, the highest power efficiency 93.36%, and the output voltage is well regulated under input voltage and load variations.

並列關鍵字

Synchronous Rectification ； ZVS ； Forward Converter ； Active-Clamp

參考文獻

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