應用無ADC之FPGA控制於多組輸出之DC-DC轉換器

Applying FPGA Control Without ADC to Multi-Output DC-DC Converter

蔡承翰(Cheng-Han Tsai)

指導教授 ： 胡國英

國立臺北科技大學/電資學院/電機工程系研究所/碩士(2009年)

摘要

於本論文中，使用具多組輸出(Multi-Output)之前向式轉換器(Forward Converter)為硬體實驗平台，其中，各組輸出電壓均可藉由迴授控制以調控其輸出電壓，而在具最大電流之輸出側採用兩相交錯式(Interleaved)架構，故除了輸出電壓控制之外，亦必須包含均流控制(Current Sharing Control)，若將其數位化進行數位控制時，則每組輸出電壓與兩相電流須經由類比數位轉換器(Analog-to -Digital Converter, ADC)取樣，而一顆高性能的ADC價格都較昂貴。故本論文在各組輸出電壓及兩相交錯式電流之取樣上，皆採用無ADC取樣技術。就系統控制而言，本論文提出在既有比例-積分-微分(Proportional-Integral-Derivative, PID)
控制器上外加一所提之非線性控制策略，以加快系統的負載暫態響應(Load Transient Response)。於本論文中，所採用之硬體平台為具三組輸出的順向式轉換器，三組輸出電壓規格分別為12V， 5V，及3.3V，其中，由於3.3V輸出之電流最大，故3.3V輸出採用兩相交錯式架構。最後，藉由理論推導及模擬來驗證所提架構與方法之可行性，並以場效可規劃邏輯閘陣列(Field Programmable Gate Array, FPGA)為系統之控制核心進行實驗以驗證其有效性。

關鍵字

無ADC取樣 ； 多組輸出DC-DC轉換器 ； 順向式轉換器 ； 交錯式 ； 均流控制 ； FPGA

並列摘要

In this thesis, the forward converter with multiple outputs is used to realize a system with fully-digitalized control without any analog-to-digital converter (ADC) used. In such a circuit, each output voltage can regulate itself via feedback control. Aside from this, the output voltage with the largest output current takes not only voltage control but also interleaved control and current sharing control. If such a system takes fully-digital control, then the number of ADCs used is large and hence the corresponding cost is expensive. Therefore, the sampling of multiple output voltages and two-phase currents without any ADC is presented herein. For the system control to be considered, an additional nonlinear control strategy is presented and added to the existing proportional integral derivative (PID) controller, so as to enhance the load transient response. In this paper, the multiple-output forward converter has three output voltages of 12V, 5V and 3.3V, where the output voltage of 3.3V possessing has the largest output current takes interleaved control and current sharing control. Via mathematical derivation and simulated waveforms, the feasibility of the proposed structure topology and control strategy can be verified. Furthermoore, the field programmable gate array (FPGA) is used as a control kernel of the system, so as to demonstrate the effectiveness of the proposed structure topology and control strategy.

並列關鍵字

Sampling Without ADC ； Multi-Output of DC-DC Converter, Forward Converter ； Interleaved Control ； Current Sharing Control ； FPGA

參考文獻

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