本文旨在分析及製作三臂式直流-直流功率轉換器並聯系統。本文之系統採用三臂式直流-直流功率轉換器架構，將低電壓源轉換為高電壓輸出，以減少輸入側大電流造成切換損與線路損失進而提高系統效率。文中根據電壓閉迴路控制策略，使三臂式直流-直流功率轉換器能提供穩定之輸出電壓至負載。三臂式直流-直流功率轉換器之並聯運轉方面，本文採用小容量及模組化之共用直流電壓源架構。經由適當的投入/切離控制，適時地並聯其它功率轉換器至系統，提高並聯運轉之容量及利用率；在並聯運轉時，搭配錯相式脈波調變降低電流與電壓漣波，並以均流策略共同平均分擔負載。
　　本文建立開關等效電路進行電路分析及控制理論推導，並以Matlab/Simulink軟體從事電路模擬。文中以高性能、低成本的數位信號處理器TMS320F2808為控制核心，實現錯相式脈波寬調變控制，並配合電壓、電流回授以完成電壓閉迴路控制，其中並聯運轉之控制策略皆由軟體程式完成，以減少硬體電路並提高系統可靠度。本文已完成約1kW並聯運轉之實體製作，單組功率轉換器為500W實體製作，輸入直流電壓為25V，輸出直流鏈電壓為200V，其電壓調整率為0.96％，輸出電壓漣波因數為1.01％，整體效率為88.4%。

　　This thesis is concerned with the analysis and implementation of parallel three-leg dc-dc power converter systems. High power three-leg dc-dc circuit structure with high power is adopted to convert the low voltage source to that of the high voltage to reduce switching loss and line loss by the large current of input, and to improve system efficiency. The voltage closed-loop control system of the power converter can provide a output voltage to load. The three-leg dc-dc power converter of common dc voltage topology designed with small-rated power modules are adopted to the proposed parallel system. The capacity and utilization rate of the parallel system can be flexibly increased by suitable switch-in and switch-off controls. Under parallel operation, interleaved pulse-width modulation is introduced to reduce current and voltage ripple. In addition, current-sharing strategy is used to accomplish load-sharing.
　　In this thesis, switch equivalent circuit is first derived and simulated by Matlab/Simulink to verify the proposed control strategy. The 32-bit digital signal processor, TMS320F2808, is used to implement the control functions of the system with the voltage and current feedbacks, and achieve the interleaved pulse-width modulation. The control of the parallel strategy is conducted by software to reduce the component count and improve system reliability. Two single systems of 25V, 500W each are built to provide a 1kW prototype with dc-link voltage of 200V. Experimental results yield a voltage regulation of 0.96%. With the output voltage ripple of 1.01% and system efficiency of 88.4%.

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