本文提出一數位化控制之降壓型直流/直流轉換器,採用電感電流波谷取樣及電流斜率參數估測實際電流,藉此完成峰值電流模式控制(Peak current mode control)。此種方式優點為有效降低電流取樣速度減少成本以及提供快速的動態負載響應。 為了設計數位控制器,本文將推導降壓型轉換器及峰值電流模式控制之數學模型並討論控制參數變動對系統穩定度之影響,由模擬驗證此控制器之性能,最後研製一以Xilinx® FPGA為控制平台,輸入電壓為12V,輸出電壓為2.5V,最大輸出電流為20A之降壓型轉換器。由實驗結果顯示在無載、滿載及快速動態負載響應下輸出電壓漣波皆小於+3%~-3%,由此結果可知此轉換器擁有快速的動態響應並且驗證理論與設計。
The main theme of this thesis is to present a digital controller for dc-dc buck converter using peak current mode control based upon estimated current which is derived by the parameter of current slope and valley current sampling. The advantages of this control method include significant reduction of sampling rate of current and providing fast dynamic response. For design the digital controller, the mathematic model of the buck converter using peak current mode is derived and the effects of parameter on system stability is discussed. Simulation results demonstrate the performance of the designed digital controller. The fully digital controller of dc-dc buck converter is implemented using Xilinx® FPGA-based board. The details of the specification are as follows: input voltage 12V, output voltage 2.5V and maximum output current for 20A. The experimental results show that the output voltage is well regulated and its ripple is less the +3%~-3% under both steady state and transient state, and thereby confirming the controller design and implementation.