陳德玉臺灣大學：電機工程學研究所謝宏毅Hsieh, Hung-IHung-IHsieh2007-11-262018-07-062007-11-262018-07-062007http://ntur.lib.ntu.edu.tw//handle/246246/53407依據傳統的理論，傳導性雜訊之分析方法一般可區分為差模和共模兩種雜訊型態，然而對於僅將傳統理論應用在雜訊分析和濾波器設計上而言，仍稍有不足。本論文針對近年來所提出之傳導性電磁干擾雜訊概念，混模雜訊（Mix-Mode EMI Noise），進行研究，並且將新的研究認知應用在濾波器的設計上。 本論文提出三種新理論。一為雜訊電流平衡（Noise Current Balancing）概念。此概念為利用電容性濾波器元件作為消除由系統上之寄生電容所產生的混模雜訊電流，以達成雜訊抑制之目的。二為共模雜訊抑制電容（Z Capacitor）之研究，本論文首次針對此一電容對於雜訊抑制的原理與機制作深入解釋和探討，並提出使用建議。此外也針對不同轉換器之電路架構提出相關的使用方法。同時於本論文中也提及變壓器的纏繞結構，與其不同纏繞方式所產生之相對應的寄生電容，對於雜訊路徑耦合的影響。實驗與模擬結果也皆能符合所提出之理論。三為提出一套快速且有系統之包含混模雜訊效應的電磁干擾濾波器設計流程。將其與傳統設計流程的結果做比較，本論文所提出之設計方法能更夠有效減少濾波器元件體積，進而達到濾波器精簡化與節省成本之目的。Conducted electromagnetic interference (EMI) noise was traditionally classified into two coupling modes, differential-mode (DM) and common-mode (CM). But there were phenomena unexplainable with this traditional theory. An additional noise-coupling mode, the mix-mode (MM), was then proposed to fill this inadequacy. The main focus of this dissertation is to explore the mix-mode noise coupling mechanism even further and use the new understanding to improve practical EMI filter designs. Specifically, three areas were explored. One was to look at the new role in one differential-mode capacitor (X capacitor) and two-serial common-mode capacitors (Y capacitors) play in filtering mechanism. Besides the conventional impedance mismatching concept, a “noise current balancing” concept was introduced. Second area of exploration was about a common-mode capacitor (Z capacitor) connection in a two-wire system which is common in many hand-held device applications. The effectiveness of such common-mode capacitor was not clear before. An explanation with the mix-mode phenomenon was proposed in this dissertation. From this proposed theory, several practical common-mode capacitor connecting means were proposed. Experiments were conducted to prove the theory. The third area of exploration was to incorporate the mix-mode considerations into a practical EMI filter design. It’s concluded that with this new approach, smaller EMI filter can be achieved.Acknowledgements, iv Abstract, vi Table of Contents, ix List of Figures, xiii Definition of Symbols, xviii Chapter-1 Introduction to EMI of Switched-Mode Power Supplies, 1 1.1 An Introduction of EMI and EMC, 1 1.2 Test Setup for Conducted EMI Emissions, 3 1.3 EMI Standards of Conducted Emissions, 5 1.4 Conventional Theory of EMI, 6 1.5 Contributions of the Dissertation, 10 1.6 Organization of the Dissertation, 11 Chapter-2 Mix-Mode EMI Noise, 13 2.1 Introduction, 13 2.2 Conventional Theory of DM and CM, 14 2.2.1 Differential-Mode EMI Noise, 14 2.2.2 Common-Mode EMI Noise, 14 2.3 Description of Mix-Mode EMI Noise, 16 2.3.1 Two of the Bridge Rectifying Diodes ON, 16 2.3.2 All the Four Bridge Rectifying Diodes OFF, 17 2.3.3 Mix-Mode EMI Noise Suppression Mechanism, 20 2.4 Noise Suppression Mechanisms, 22 2.4.1 Impedance Mismatch, 22 2.4.2 Mix-Mode EMI Noise Current Balancing, 23 2.4.3 Use of Y Capacitors on Noise Current Balancing, 25 2.5 Summary, 26 Chapter-3 Effects of X Capacitors on EMI Filter Effectiveness, 27 3.1 Introduction, 27 3.2 Issues with X Capacitors, 28 3.2.1 Arrangement of Capacitance Value, 28 3.2.2 Location of X Capacitor, 31 3.2.3 Oversizing X Capacitance, 35 3.2.4 Effects of Y Capacitors on Current Balancing, 35 3.2.5 Effects of X Capacitor on CM Noise, 37 3.3 Summary, 37 Chapter-4 EMI Filter Design Procedure Incorporating Mix-Mode Noise, 41 4.1 Introduction, 41 4.2 Noise Suppressing Mechanisms of EMI Filter, 42 4.3 A Filter Design Procedure Incorporating Mix-Mode Noise, 44 4.4 Design Example, 45 4.4.1 Baseline EMI Measurement using a Noise Separator, 46 4.4.2 Determination of Filter Attenuation Requirements, 46 4.4.3 Determination of Corner Frequencies, 49 4.4.4 Determination of Filter Component Values, 49 4.4.5 Fine-tuning Cx2 Value, 50 4.4.6 High-frequency Problems, 51 4.5 Experimental Verifications, 51 4.5.1 Summary of the Experimental Results, 51 4.5.2 Comments about Results, 52 4.6 Summary, 55 Chapter-5 Common-Mode Z Capacitor, 59 5.1 Introduction, 59 5.2 Noise Suppression Mechanism of Z Capacitor, 60 5.2.1 Diodes OFF, 61 5.2.2 One Diode Pair ON, 62 5.3 Experimental Breadboards and Circuit Simulations, 63 5.4 Suggestions for Proper Z Capacitor Connection, 65 5.4.1 Connection Points Recommendation, 65 5.4.2 Connection Points to be Avoided, 69 5.4.3 Leakage Current, 73 5.5 Z Capacitor Connection Schemes for Converter Configurations, 74 5.6 Effects of Transformer Winding Techniques and Output Choke Placement, 74 5.6.1 Effects of Transformer Winding Techniques, 74 5.6.2 Effects of Output Choke Placement, 80 5.7 Effectiveness of Z Capacitors, 83 5.8 Summary, 88 Chapter-6 Conclusions, 89 6.1 Conclusions, 89 6.2 Future Work, 91 References, 92 Appendix-A Noise Separator, 108 A.1 Introduction, 108 A.2 Measurement of Conducted EMI Emissions, 109 A.3 Noise Separator, 110 A.3.1 Power Splitter and Power Combiner, 110 A.3.2 Arrangement and Performance of the Noise Separator, 111 A.4 Use of the Noise Separator in EMI Measurement, 115 A.5 Summary, 1172916989 bytesapplication/pdfen-US混模雜訊差模雜訊共模雜訊阻抗不匹配電流平衡Z電容雜訊分離器Mix-Mode (MM)Differential-Mode (DM)Common-Mode (CM)Impedance MismatchCurrent BalancingZ Capacitor (Cz)Noise Separatorthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/53407/1/ntu-96-D92921005-1.pdf