指導教授：陳秋麟臺灣大學：電子工程學研究所鄭惟駿Cheng, Wei-ChunWei-ChunCheng2014-11-302018-07-102014-11-302018-07-102014http://ntur.lib.ntu.edu.tw//handle/246246/263864近年來，為了提高電力系統的使用效率，各國陸續制定了電器產品的諧波電流規範標準，功率因數校正器成為了電源供應系統中不可或缺的一部分。其中邊界模式切換式電源供應器由於其高效率特性，最常被應用於功率因數校正器的實作。而其高效率的關鍵在於邊界模式可以在不加入額外離散元件的情況下實現柔性切換技術，藉此減少功率開關的切換損耗。然而，由於功率因數校正器的交流輸入特性，其電壓與電流的共振波形在每個切換週期皆不相同，但現今市面上的控制電路皆以固定的電壓或電流做為功率開關的切換比較基準，這使得功率開關的切換點無法適應週期間波形的變化，造成多餘的功率開關切換損失及導通損失。 有鑑於此，我們提出了一種最佳低電壓切換技術，並將其應用於邊界模式功率因數校正器。此方法利用共振波形的對稱特性，於每個切換週期預測功率開關的最佳切換時機，同時計算閘極驅動電路的延遲時間，使得功率開關的實際切換時機落在最佳切換點，以實現最佳化零電壓切換或最低電壓切換。此方法可適用於任何架構的邊界模式共振轉換器。本論文詳細介紹並分析此最佳低電壓切換技術，同時提出實現此方法所需的電路與系統。 為了驗證電路特性，我們以0.5-um的N-well製程實作了一採用所提出之最佳低電壓切換技術的功率因數校正器控制晶片，並將其實際應用於50瓦的邊界模式升壓型功率因數校正轉換器。量測結果證明本文所提出的方法與電路確實可使功率開關精確地切換於最佳化的最低電壓點，降低功率開關的切換損失，進而提升整體轉換器的效率。In recent years, the standard of input harmonic currents of electronic devices has been set to maintain high quality public mains power networks. The power factor correctors have become an essential part of power supply systems. The power factor correctors are mostly implemented with boundary mode switching converters because of its high efficiency. For a boundary mode converter, soft-switching techniques can be applied without additional discrete components, which minimize the switching loss of the power MOSFET. In conventional control methods, the switching timing of the power MOSFET is determined using fixed thresholds. However, for a power factor corrector, the resonant voltage and current waveforms are different in each switching cycle since its input is an AC voltage. It makes the switching timing of the power MOSFET away from the optimal timing, which increases the switching loss and the conduction loss. Therefore, we proposed the optimal lowest-voltage-switching for boundary mode power factor correctors. Utilizing the symmetric characteristic of the resonant waveforms, the optimal switching for the power MOSFET can be realized in consideration of the gate driver delay. The proposed approach achieves optimal zero-voltage-switching or valley-switching operation automatically to minimize the switching loss. The proposed lowest-voltage-switching technique can be applied to other resonant converters as well. The detailed analyses and circuit implementations are described in this dissertation. In order to verify the proposed methods and circuits, a 50 W boundary mode boost PFC converter with the proposed optimal switching technique has been implemented using a 0.5um N-well process. Experimental results show that the proposed approach can realize optimal soft switching, and improve the efficiency of the boost PFC converter.誌謝 # Abstract (Chinese) i Abstract ii Table of Contents iv List of Figures vii List of Tables xi Chapter 1 Introduction 1 1.1 Background and Motivation 1 1.2 Dissertation Overview 3 Chapter 2 Fundamentals of Boundary Mode Power Factor Corrector 5 2.1 Power Factor Corrector 5 2.2 Boundary Mode PFC Converters 8 2.2.1 Boost Topology 8 2.2.2 Flyback Topology 11 2.3 Soft-Switching Techniques 14 2.3.1 Zero-Voltage-Switching 16 2.3.2 Valley-Switching 17 2.4 Zero Current Detection 19 2.4.1 Voltage Comparison Method 19 2.4.2 Current Comparison Method 21 2.4.3 Waveform Variation 22 2.4.4 Gate Driver Delay 23 2.5 Summary of Boundary Mode PFC converters 25 Chapter 3 Optimal Lowest-Voltage-Switching 27 3.1 Operation Principle 27 3.1.1 Optimal Zero-Voltage-Switching 28 3.1.2 Valley-Switching 29 3.1.3 Damping Effect Analysis 31 3.2 Circuit Implementations 32 3.2.1 Negative Voltage Blocking Circuit 33 3.2.2 Timing Detection Circuits 35 3.2.3 Timer Circuit 38 3.3 Boundary Mode Boost PFC Prototype 40 3.3.1 Multiplier Circuit 41 3.3.2 Control Loop Analysis 45 3.3.3 Effect on Line-Current Distortions 49 3.4 Summary of Optimal Lowest-Voltage-Switching 52 Chapter 4 Experiments 54 4.1 Measurement Results 54 4.2 Summary of Experiments 64 Chapter 5 Conclusions 66 5.1 Dissertation Summary 66 5.2 Future Work 67 Reference 693629938 bytesapplication/pdf論文公開時間：2017/08/16論文使用權限：同意有償授權(權利金給回饋學校)功率因數校正器切換式電源供應器共振式轉換器零電壓切換波谷切換thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/263864/1/ntu-103-F97943128-1.pdf