電流型態控制直流/直流電壓轉換器之控制特性模擬

Practical Simulations of Control Characteristics of a Current-Mode DC/DC Converter

王珽弘(Ting-Hung Wang)

指導教授 ： 陳德玉

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.00542

摘要

在一個電流型態控制的直流電壓轉換器中，通常存在著兩條迴路：一條電壓迴路與一條電流迴路，因此而產生了兩個主要的迴路增益：T1與T2。此兩種迴路增益直接地影響了直流電壓轉換器的穩定度以及效能。因此，在電流型態控制的直流電壓轉換器之設計中，對於這些迴路增益的認識與瞭解是非常重要的。而在設計此種直流電壓轉換器時，有兩種方法被廣泛地加以運用；其中一種方法討論T1與T2，另外一種方法則是探討一個在只有電流迴路關閉之下定義的新轉移函數Fin。此新轉移函數Fin不僅顯現了系統的穩定度資訊，也提供了對於電壓迴路補償設計的相關訊息。因此，在一個實際可行的系統下如何運作並衍生此三種迴路增益函數成為了本篇論文的主旨。
在本篇論文中，我們使用SIMPLIS軟體來模擬電流型態控制的直流電壓轉換器中的如下函數：迴路增益T1與T2、內迴路增益Fin、電流迴路增益Ti與電壓迴路增益Tv，而模擬的過程方法也會在此篇論文中詳細說明。此篇論文使用的模擬架構皆為實用、簡單、可與其他新研發之電壓控制器相互整合，正確度也可達到操作頻率之上。除此之外，本論文使用的SIMPLIS電路也可使用於時域分析之模擬而同時不會失去PWM切換頻率的特性。這些架構或許可提供電壓轉換器設計者與IC控制器設計者在設計電路時能有效運用的資訊。
在本篇論文中，對於電壓控制型態以及電流控制型態的控制模式皆會被簡略地重新探討。對於小訊號迴路增益之轉移函數的基本概念也會被再次複習。而本論文的主要目標在於第三章，為了替第三章的討論先行奠下基礎，對於T1以及T2此兩種電流型態控制Buck轉換器之迴路增益也會在本論文中詳細討論。文中並會詳細介紹關於如何模擬T1迴路增益的步驟，而此方法在使用上可比其餘可用的模擬方式簡易許多。關於這些模擬之理論值的計算結果也會被拿來與軟體的量測結果做相互的對照。在論文的最後，第四章總結了本篇論文並提出了未來進一步的研究方向。

關鍵字

電流型態 ； 直流/直流電壓轉換器 ； 控制 ； 模擬

並列摘要

In a current-mode controlled DC converter, there are two feedback loops: a current loop and a voltage loop. There are, therefore, two loop-gain functions T1 and T2 involved. Behavior of the two loop-gain functions affects system stability and converter performances. Therefore, knowledge about the actual circuit loop gains is critically important in the design of the converters. Two approaches to the design of current-mode converters are often mentioned. One uses the concept of the two loopgain
functions T1 and T2, and the other uses a new converter transfer function Fin to describe the control plant when only the current loop is closed. Fin not only reveals
stability issue but also provides information for the design of voltage-loop compensation. Obtaining these three functions under a realistic environment is the main focus of this thesis.
In this thesis, procedures were proposed to simulate the two loop-gain functions T1 and T2, the inner loop transfer function Fin, current-loop gain Ti and voltage-loop gain Tv, for a current-mode controlled DC/DC Buck converter using SIMPLIS software. These models are practical to obtain, simple to use, accurate beyond switching frequency and are easily amendable to incorporate new converter
configurations and new control schemes. Furthermore, the same SIMPLIS models can also be used to simulate time-domain waveforms without losing PWM switching frequency information. These models should provide useful information for both the converter circuit designers and the IC controller designers.
In the thesis, a brief review of the control schemes of both voltage-mode and current-mode is given in Chapter 2. Basic concept of small-signal loop gain transfer functions is reviewed. A detailed description of the two loop gain functions T1 and T2 in current-mode controlled Buck converters in this chapter lays the foundation for
Chapter 3, which is the main focus of this thesis. A step-by-step procedure is proposed to simulate loop gain T1 which is difficult to obtain using any other way. These simulation results were verified by using theoretical models. Chapter 4 concludes the thesis and suggests future research topics.

並列關鍵字

Simulation ； Control ； Current-Mode ； DC/DC Converter

參考文獻

[1] R.B. Ridley, Bo H. Cho, and Fred C.Y. Lee, “Analysis and Interpretation of Loop Gains of Multiloop-Controlled Switching Regulators,” IEEE Transactions on Power Electronics. Vol. 3, No. 4, October. 1988

[2] R.B. Ridley, “A New Continuous-Time Model for Current-mode Control,” Power Conversion and Intelligent Motion Conference, October 1989

[3] Vatche Voperian, “Simplified Analysis of PWM Converters Using Model of PWM Switch,” IEEE Transactions on Aerospace and Electronic Systems, Vol. 26, Issue 3, May 1990

[6] R.D. Middlebrook, “Small-Signal Modeling of Pulse-Width Modulated Switched-Mode Power Converters,” Proceedings of the IEEE, Volume 76, Issue 4, April 1988 Page(s): 343-354, Digital Object Identifier 10.1109/5.4421

[7] Martin Lee, Dan Chen, Chih-Wen Liu, Kevin Huang, Eddie Tseng and Ben Tai, “Compensator Design for Adaptive Voltage Positioning (AVP) for Multiphase VRMs,” in Proc. IEEE PESC, 2006.