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The Stability Analysis of a Ripple-Based Constant On-Time Voltage Regulator with a DC-Offset Correcting Circuit
No full text近年來，漣波調變定導通時間之控制架構因其在輕載與重載皆具高效率的特性，使其廣泛被運用於電壓調節器等應用。然而漣波調變定導通時間之控制架構通常伴隨輸出電壓準位的誤差，因此在需要精準輸出電壓之應用上極需加直流準位誤差校正電路至漣波調變定導通時間之控制架構。本篇論文主要探討準位校正漣波調變定導通時間之控制架構的穩定度分析。
在漣波調變定導通時間控制機制下，由於輸出電壓之切換頻率漣波會影響脈衝寬度調變之操作過程，因此無法使用傳統小訊號模型加以分析，然而描述函數的方式可成功應用於漣波調變定導通時間之控制架構。但若將準位校正漣波調變定導通時間之控制架構完全以描述函數來進行建模且不具有調變訊號須為直流無漣波的假設，會使數學分析變得相對複雜。本論文不僅運用具有基本假設之描述函數方法進行分析，論文中也使用分析時域波形伴隨實驗觀察之方法來對此議題進行研究，並以此建立穩定度準則。
此論文中穩定度準則的建立，能有效解決準位校正漣波調變定導通時間之控制架構的穩定度議題，並以模擬及實驗結果來作為驗證。且此穩定度準則的建立，不僅有助於實際電路的穩定度，也能做為有效減少控制晶片面積之依據。In recent years, the ripple-based constant on-time (RBCOT) control scheme for voltage regulators has been adopted in many applications because of its high efficiency feature under both the heavy-load and the light-load conditions. However, the basic RBCOT control suffers from output-voltage offset problem. Therefore, an offset correcting circuit (OC) is sometimes added to the basic RBCOT scheme to correct the problem for the applications in which output voltage precision is critical. This control scheme is abbreviated as OCRBCOT in this thesis. The main focus of this thesis is on the stability issue of a buck converter regulator using the OCRBCOT control scheme.
Traditional low-frequency small-signal average models cannot be applied to the basic RBCOT due to inaccuracy [1]. A describing function approach was proposed and applied to model the behavior of a buck converter regulator employing the basic RBCOT scheme [2]. To model the conventional regulator using describing function approach is mathematically too complicated to be feasible.
In this thesis, a time-domain analysis approach with a semi-empirical observation is used to address this issue. Experimental and simulation results are given to verify the stability criterion derived. The result obtained in the thesis, while not analytically proved, provides a useful tool for addressing the stability issue of a buck regulator with OCRBCOT control scheme. It also provides a way to eliminate the proper RC value of the offset correcting circuit to minimize the chip area of the OCRBCOT controller integrated circuit.口試委員會審定書........................................i
誌謝.................................................ii
中文摘要.............................................iii
ABSTRACT............................................iv
CONTENTS............................................vi
LIST OF FIGURES.....................................ix
LIST OF TABLES......................................xi
Chapter 1 Introduction.........................1
1.1 Background....................................1
1.2 Description of a Buck Converter Using Ripple Based Control..............................................2
1.2.1 Description of a Ripple Based Constant On-Time Control Circuit......................................2
1.2.2 Description of a Ripple Based Constant On-Time Control with DC-Offset Correcting Circuit (OCRBCOT)..4
1.3 Thesis Organization...........................5
Chapter 2 Modeling Methods for Ripple Based Control..7
2.1 Introduction.....................................7
2.2 The Development of OCRBCOT Control Using an Extended Describing Function Approach.........................8
2.2.1 Review of the RBCOT Control Based on Describing Function Approach....................................8
2.2.2 Extending the Describing Function Approach to OCRBCOT Converter....................................12
2.2.2.1 The Inner-loop Stability Criterion.......13
2.2.2.2 The Outer-loop Stability Criterion.....13
2.3 Inaccuracy of the Stability Criteria Based on the Extended Describing Function Approach............15
2.3.1 The Verification of the Extended DF Method.15
2.3.2 Discussion for the Inaccuracy of the Extended DF Method...............................................19
Chapter 3 Modeling and Stability Analysis of OCRBCOT Buck Converter Using Time Domain Analysis...................20
3.1 Time Domain Analysis of OCRBCOT Buck Converter....21
3.1.1 Derivation of Vo(t) and Vrefnew(t).............21
3.1.2 The Verification Vo(t) and Vrefnew(t)..........26
3.2 Apply the Stability Criterion for DCM Operation to CCM Operation..........................................27
3.2.1 The Development of the Application of the Stability Criterion for DCM Operation to CCM Operation...........27
3.2.2 The Verification of the Inaccuracy in the Application of the Stability Criterion for DCM Operation to CCM Operation.........................................29
3.3 The Development of Stability Criterion for OCRBCOT Buck Converter Using Time Domain Analysis..................31
3.3.1 Introduction..................................31
3.3.2 The Description of the Stability Criterion....35
3.3.3 The Derivation of dVrefnew and dVcross.....36
Chapter 4 Verification of the Stability Criterion for OCRBCOT Circuit.........................................46
4.1 Verification of Stability Criterion by Simulation..46
4.2 Verification of Stability Criterion by Experiment..59
Chapter 5 Conclusions and Suggested Future Research.....64
5.1 Conclusions.....................................64
5.2 Suggested Future Work...........................65
Appendix................................................67
References..............................................7
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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