- 學位論文
數位控制直流-直流轉換器研製
Design and Implementation of Digital Controlled DC-DC Converters
摘要
本論文旨在研製數位控制直流-直流轉換器。本論文首先討論不同取樣頻率、不同脈波寬度調變模式及各種時間延遲所造成相位落後的影響，並推導數位控制直流-直流轉換器的等效模型，此等效模型考慮前述由取樣頻率、脈波寬度調變模式及時間延遲所造成的相位落後。經由比較模擬及量測結果驗證等效模型的正確性。其次，本論文討論不同種類的補償器對系統的影響，包括了直流增益、系統頻寬及相位邊限等，並應用各種補償器於直流-直流轉換器實驗系統上，以確認補償器設計的有效性。 最後，因預測式電流控制對於系統參數變動，產生包括電感電流穩態誤差及追蹤誤差，本論文針對參數變動對預測式電流控制產生的影響進行分析，並提出一種應用於預測式電流控制的線上參數估測方法，此方法只須增加一切換週期中的電流取樣，無需額外的感測器及系統參數，此方法可應用於定頻操作的轉換器，或是操作於邊界導通模式的轉換器。經由模擬及實驗的結果，證實本論文所提出的線上參數估測方法，可充分克服參數變動，對轉換器產生包括電感電流穩態誤差及追蹤誤差的影響。
並列摘要
The main theme of this dissertation is to design and implement digital controlled DC-DC converters. First, the phase lags caused by different sampling rates, digital pulse-width modulation methods, and time delays on digital controlled applications are introduced. Model of digital controlled DC-DC converters considering the above-mentioned effects are analyzed and developed. The validity of the developed model has been verified by simulation and experiment. After that, the effects of different compensators on the closed-loop system including DC gain, bandwidth, and phase margin are introduced and analyzed. An experimental system has been developed to verify the performance of different compensators. Finally, the issues, including steady state error and tracking error of inductor current, caused by parameter variation in predictive current mode control are analyzed. Predictive current mode control senses inductor current at the beginning of a switching period and predicts inductor current waveform by known system parameters. Since system parameters, especially, inductance and the effective cross voltage of inductor, are variable and can not be accurately measured, on-line parameter tuning techniques for predictive current mode control are proposed in this dissertation. The proposed on-line parameter tuning technique is based upon adding an additional current sampling between two PWM outputs. Neither additional sensor nor system parameter is required for the realization of the proposed technique. The proposed on-line tuning technique is suitable for both constant frequency operation applications and variable frequency operation with boundary conduction mode applications. The effectiveness of the proposed methods, including elimination of steady state error and tracking error of inductor current, has been confirmed by simulated and experimental results.