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研究生： 時立中
Li-Chung Shih
論文名稱： 高效率全橋轉換器之多模式控制技術
A novel hybrid mode control for phase-shift full bridge converter featuring high efficiency
指導教授： 邱煌仁
Huang-Jen Chiu
劉益華
Yi-Hua Liu
口試委員: 邱煌仁
Huang-Jen Chiu
劉益華
Yi-Hua Liu
楊宗銘
Chung-Ming Young
鄧人豪
Jen-Hao Teng
王順忠
Shun-Chung Wang
羅一峰
Yi-Feng Luo
學位類別： 博士
Doctor
系所名稱： 電資學院 - 電子工程系
Department of Electronic and Computer Engineering
論文出版年： 2018
畢業學年度： 107
語文別： 中文
論文頁數： 128
中文關鍵詞： 脈衝模式 、脈波寬度調變 、相移調變 、非對稱脈波寬度調變 、多模式控制 、適應性停滯時間控制
外文關鍵詞： Burst mode control, Pulse-width modulation, Phase-shift modulation, Asymmetric pulse-width modulation, Hybrid mode control, Adaptive dead-time control
相關次數： 點閱：340  下載：8 
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    • 全橋轉換器一般都適用於中大功率轉換的應用場合，而全橋轉換器的主要控制技術包括有傳統脈波寬度調變、非對稱脈波寬度調變以及相移調變等技術。近年來，許多研究學者都較著重於相移調變相關技術研發，因為相移調變技術應用於全橋轉換器，簡稱相移全橋轉換器，不需要額外硬體線路，其零電壓切換的特性就可延伸至更寬廣的負載範圍。
    為了使相移全橋轉換的性能有更進一步的提升，許多技術均以相移全橋模式為基礎，輔以增加硬體線路或元件的改善方案，使得全橋相移轉換器有更好的性能，但過多的硬體線路將會對成本、產品體積與產品可靠度等方面造成衝擊。隨著數位控制器的發展，數位化的控制實現了許多複雜的控制法則，於是一般類比控制器較難以實現的多模式控制技術漸漸受到重視，因為多模式的控制技術，除了不會增加任何成本之外，其相較於傳統類比線路的單一模式控制，將有更大的設計彈性與性能進步的空間。
    本文首先介紹相移全橋架構的優缺點以及文獻所提出之改善方案討論。接著，將傳統脈波寬度調變、相移調變與非對稱脈波寬度調變等控制技術應用在全橋架構並進行討論與比較。最後，基於以上三種控制方法的分析，發展出一套適用於全橋轉換器之多模式切換控制技術；其對於中載與重載，分別使用相移調變控制與非對稱脈波寬度調變控制；對於輕載，則以脈衝模式來處理。
    至於本文多模式切換的基本概念則是利用一個比較低的變壓器圈數比，使其操作在相移調變控制模式之下，此時其責任週期將會高於傳統相移全橋轉換器變壓器設計的責任週期，較大的責任週期就可以壓縮相移全橋轉換器的環流區間來達到減少環流損失的目的。但責任週期的增加相對也減少了責任週期的餘裕空間，於是較低圈數比的變壓器操作在相移調變控制模式之下，其輸出電壓有可能到達滿載之前，就先行掉落至規格之外，這是因為此時的責任週期幾乎已經等於1，無足夠責任週期餘裕可以進行輸出電壓補償。故當此種情形發生時，就必須改由非對稱脈波寬度調變模式操作，以使輸出電壓在滿載仍能符合規格需求。
    此外，全橋轉換器各橋臂之間的停滯時間也是使效率提升的關鍵因素之一，透過彈性的處理停滯時間，使其在不同負載之下，有不同的停滯時間，進而使全橋轉換器的效率有更進一步的提升。
    最後，本文以數位訊號處理器實現所提出之多模式全橋控制技術，並實際製作一個輸出功率為480W (24V/20A)之直流/直流轉換器來驗證本文所提出之多模式全橋控制技術的正確性與可行性。同時根據實驗結果，本系統在10%、30%、與滿載時的效率分別比傳統相移全橋轉換器高約3.2%、1.3%與0.6%，而整體之平均效率比傳統相移全橋轉換器高約1%~2%。
    關鍵字: 脈衝模式、脈波寬度調變、相移調變、非對稱脈波寬度調變、多模式控制、適應性停滯時間控制

    Full Bridge Converter is generally suitable for medium to high power applications. The control technologies of the full bridge converter mainly includes traditional pulse-width modulation control, asymmetrical pulse-width modulation control and phase-shift modulation control, etc. In the past years, many studies have been focusing on research of the full bridge converter with phase-shift modulation control which is called phase-shift full bridge. Because phase-shift full bridge has inherent zero voltage switching ability over a wider load range.
    Recently, in oder to further improve the properties of the phase-shift full bridge, many methods are assisted with some hardware circuits as improvement strategies to enhance the performances of the phase-shift full bridge converter. However, too many hardware circuits are often harmful to the cost, size, reliability, etc. Nowadays, with the development of digital signal controllers, performance enhanced by using software in stead of using hardware is gradually gaining attention. Because software can achieve complex control algorithm which is more difficult to be realized with analog controllers. Besides, software do not increase the cost and it allows more room for design flexibility and performances improvement.
    This thesis first introduces the advantages and disadvantages of phase-shifted full bridge and privides a literature review for improvement methods that have been proposed. Later, it discusses and compares above three different control technologies that are applied on the full bridge converter. Then, based on the analysis of the above-mentioned three control methods, a novel hybrid mode control technique for the phase-shift full-bridge converter is proposed in this thesis. The proposed method can improve power efficiency under both light-load and heavy-load conditions. For medium load and heavy load, it operates with phase-shift modulation control and asymmetric pulse-width modulation control respectively. For stand by mode, it operates in the burst mode control.
    The basic concept of the proposed control technique is to decrease the turns ratio of the transfomer to reduce the circulating current of the phase-shift full bridge converter; hence results in lower circulating losses. However, the output voltage under heavy load may not be stabilized using phase-shift modulation control if smaller turns ratio is utilized. Therefore, the proposed technique employs asymmetric pulse-width modulation control to achieve a stable output voltage during heavy-load conditions.
    In addition, to further improve the efficiency, an adaptive dead-time control method which determines the dead-time value according to the load level is also proposed.
    To validate the correctness and effectiveness of the proposed method, a 480-W phase-shift full bridge converter is constructed and experiments are carried out accordingly. Comparing with conventional phase-shift full-bridge converter, an averaged 1.2% efficiency improvement can be achieved without any additional auxiliary circuits. According to the experimental results, the efficiency of the proposed method can be improved up to 3.2%, 1.3% and 0.6% under 10% load, 30% load and full-load conditions, respectively.
    Keywords: Burst mode control, Pulse-width modulation, Phase-shift modulation, Asymmetric pulse-width modulation, Hybrid mode control, Adaptive dead-time control.

    摘要 I Abstract III 誌謝 VI 目錄 VIII 符號索引 XII 圖目錄 XIX 表目錄 XXII 第一章 緒論 1 1-1研究背景 1 1-2文獻探討 4 1-2-1責任週期損失的改善 4 1-2-2二次側振鈴現象的改善 5 1-2-3零電壓範圍的擴展 8 1-2-4環流的改善 12 1-2-5多模式控制技術 12 1-3研究動機與方法 14 1-4內容大綱 15 第二章 全橋轉換器的控制策略與其優缺點考量 17 2-1脈波寬度調變全橋轉換器之操作模式分析 18 2-2相移全橋轉換器之操作模式分析 22 2-3非對稱脈波寬度調變全橋轉換器之操作模式分析 30 2-4全橋轉換器控制方法之綜合考量 37 第三章 相移全橋轉換器環流現象的改善 40 3-1相移全橋轉換器的環流現象 41 3-2相移全橋轉換器環流區間的計算 42 3-3降低相移全橋轉換器環流區間的方法研究 45 3-4本文降低相移全橋轉換器環流的方法討論 51 3-4-1變壓器圈數比設計 51 3-4-2相移全橋轉換器的變壓器圈數設計 51 3-4-3多模式控制技術 54 3-4-4多模式控制技術之切換時機 55 第四章 適應性停滯時間的計算 58 4-1非對稱脈波寬度調變全橋轉換器停滯時間的估算 58 4-1-1停滯時間Δt1A=[t1, t2]的估算 59 4-1-2停滯時間Δt2A=[t4, t5]的估算 61 4-2相移全橋轉換器達成零電壓切換所需的停滯時間估算 63 4-2-1領先臂的停滯時間 Δt1p=[t2, t3]估算 64 4-2-2落後臂的停滯時間 Δt2p=[t4, t5]估算 65 4-3本文提出之混合模式控制方法示意圖 67 第五章 相移全橋轉換器的損耗分析 69 5-1相移全橋轉換器各功率元件的損耗估算 69 5-1-1一次側功率開關Q1~Q4的切換損 69 5-1-2一次側功率開關Q1~Q4的導通損 70 5-1-3一次側功率開關Q1~Q4閘極驅動損 70 5-1-4二次側輸出二極體D1~D2的導通損 70 5-1-5二次側輸出二極體D1~D2的截止反向恢復損 71 5-1-6變壓器T1的損耗 71 5-2環流與整體損耗的關係 72 第六章 硬體規格與元件設計 74 6-1硬體規格設定 74 6-2 一次側元件設計與選用 74 6-2-1主變壓器設計 74 6-2-2諧振電感設計 76 6-2-3隔離電容設計 78 6-2-4一次側功率開關的選擇 79 6-3二次側元件設計與選用 80 6-3-1輸出電感的設計 80 6-3-2二次側輸出整流二極體的選擇 80 第七章 實驗結果與討論 82 第八章 結論與未來展望 94 8-1結論 94 8-2未來展望 95 參考文獻 96

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