【摘要】：移相全橋ZVS變換器在中大功率應用場合備受青睞，其中變壓器漏感與功率管寄生電容的諧振實現(xiàn)了各開關管的零電壓開關，變換器效率較高。可是其副邊整流二極管存在寄生振蕩、軟開關范圍窄、占空比丟失、環(huán)流損耗大等缺陷限制了變換器的進一步推廣。特別是副邊的寄生振蕩問題不僅提高了整流裝置的電壓應力和導通損耗，同時給系統(tǒng)引入了嚴重的電磁干擾。本文針對實際場合中大功率變換應用系統(tǒng)，選取主電路拓撲為全橋變換器進行研究。 論文首先對軟開關全橋變換器進行了分類，詳細介紹了移相ZVS全橋變換器的優(yōu)缺點及其研究現(xiàn)狀，指出寄生振蕩產(chǎn)生的危害，確定本文研究重點是抑制全橋ZVS變換器副邊寄生振蕩的新方法。 論文第二章，主要對移相全橋ZVS變換器副邊寄生震蕩機理進行研究，分別分析了超前臂和滯后臂的換流原理，并比較二者的不同，基于此不同之處提出利用超前環(huán)流思想抑制副邊振蕩的新對策。 其次，提出了一種基于LCC輔助電路的新型ZVS全橋變換器。該變換器中，由于整流管提前換流，副邊整流二極管上的寄生振蕩得到有效的抑制，且副邊不存在占空比的丟失，，同時利用LC輔助電路和濾波電感中的能量所有的功率管都可以在寬負載范圍內(nèi)實現(xiàn)軟開關。本文分析了該變換器的工作原理，討論了其主要的參數(shù)設計，并進行了實驗驗證。 接著，本文根據(jù)上一新型變換器的缺陷，提出了一種改進型的ZVS全橋變換器。改進型全橋變換器中引入了輔助變壓器，增大了換流電壓幅值，大大加快了原邊換流速度，副邊寄生振蕩抑制效果明顯。此外，還引入了輔助耦合電感來拓寬超前管與滯后管的零電壓開關范圍。并且改進型變換器不存在環(huán)流時間，輸出濾波電感紋波電流得到抑制，利于濾波器尺寸的縮小。本文詳細分析了該變換器的工作原理，討論了其參數(shù)設計原則，并搭建樣機進行了實驗驗證。 最后論文對研究內(nèi)容進行了總結(jié)，并基于方案的不足之處給出了需進一步做的工作。
[Abstract]:Phase-shifted full-bridge ZVS converters are popular in medium and high power applications, in which the leakage inductance of transformers and the resonance of parasitic capacitors of power transistors realize the zero-voltage switching of each switch, and the converter is more efficient. However, the parasitic oscillation of the secondary side rectifier diode, the narrow range of soft switching, the loss of duty cycle and the large circulation loss limit the further development of the converter. Especially the parasitic oscillation of the secondary edge not only increases the voltage stress and the conduction loss of the rectifier but also introduces serious electromagnetic interference to the system. In this paper, the main circuit topology is selected as the full bridge converter for the practical application system of large power conversion. Firstly, the soft-switching full-bridge converter is classified, and the advantages and disadvantages of phase-shifted ZVS full-bridge converter are introduced in detail, and the harm of parasitic oscillation is pointed out. It is determined that the emphasis of this paper is to suppress the secondary parasitic oscillation of full-bridge ZVS converters. In the second chapter, the principle of secondary side parasitic oscillation of phase-shifted full-bridge ZVS converter is studied. The commutation principle of lead arm and hysteresis arm is analyzed, and the difference between them is compared. Based on these differences, a new strategy to suppress the secondary oscillation by using the idea of advanced circulation is proposed. Secondly, a novel ZVS full bridge converter based on LCC auxiliary circuit is proposed. In the converter, the parasitic oscillation on the secondary rectifier diode is effectively suppressed because of the rectifier in advance, and there is no duty cycle loss in the secondary side. At the same time, all the power transistors in the LC auxiliary circuit and the filter inductor can realize soft switching in a wide load range. In this paper, the principle of the converter is analyzed, and its main parameter design is discussed. Then, according to the defects of the new converter, an improved ZVS full bridge converter is proposed. An auxiliary transformer is introduced into the improved full-bridge converter, which increases the amplitude of commutation voltage, greatly speeds up the commutation speed of the original side, and reduces the parasitic oscillation of the auxiliary side obviously. In addition, an auxiliary coupling inductor is introduced to widen the range of zero voltage switches between lead and hysteresis transistors. And the improved converter has no circulation time, the output filter inductor ripple current is suppressed, and the filter size is reduced. In this paper, the working principle of the converter is analyzed in detail, and the design principle of its parameters is discussed. Finally, the research content is summarized, and the further work is given based on the shortcomings of the scheme.
【學位授予單位】：南京航空航天大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM46

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相關博士學位論文 前1條

1 顧亦磊;集成模塊電源拓撲標準化的研究[D];浙江大學;2008年

本文編號：2399938