本論文主旨為研製適用於全載範圍操作之全橋相移式串聯諧振直流/直流電源供應器，其控制策略綜合了全橋式串聯諧振轉換器(Full-Bridge Series Resonant Converter, FBSRC)與全橋相移式轉換器(Phase-Shifted Full-Bridge Converter)的特點。首先說明這兩種轉換器之動作原理與狀態分析，並分別推導其於各狀態區間之數學模型。針對輕載操作時串聯諧振轉換器並無法藉由提高切換頻率有效地調節輸出電壓維持在所需的規格範圍內，本論文提出利用調變脈波寬度調變的方式改善輕載控制策略，並分析與討論增益函數、責任週期與切換頻率三者之間的關係。本論文所提之控制策略具有以下特性：重載時電路工作於串聯諧振模式，電路具有零電壓切換之特性；而輕載操作時除了藉由調變責任週期達到穩壓之外，並利用其死域(Dead Time)期間產生諧振使電路仍然保持零電壓切換(Zero-Voltage Switching, ZVS)特性，因此由輕載至滿載皆可實現高轉換效率之目的。
論文中將詳盡介紹各種模式下的電路動作狀態，與分析各動作區間之等效電路，並推導整體電路增益等效模型，且研製一台規格為2 kW (48 V/42 A)的全橋相移式串聯諧振轉換器，說明設計步驟與效率分析，除了將實測結果和理論相互印證之外，另外也可估計功率損耗，並研擬未來研究方向。

This thesis focuses on the design and control of a phase-shifted full-bridge series resonant converter (PS-FB-SRC). The basic operating principles and state analysis of the proposed converter are discussed in detail. The output voltage of a series resonant converter is difficult to be well-regulated at light-load conditions since the switching frequency cannot be increased beyond the designated maximum frequency. In this thesis, the phase-shifted pulse width modulation (PWM) is used to reduce the effective duty cycle and confine the output voltage in a regulated range at light loads and even no load. The relationship among voltage gain, switching frequency and effective duty cycle are discussed and analyzed. The proposed full-bridge phase-shift series resonant converter features a novel two-mode operation. That is, it is operated in series resonant mode during heavy loads and in phase-shifted PWM mode during light loads. Both operating modes achieve zero voltage switching during dead times. Therefore, the proposed converter exhibits high conversion efficiency for wide-range load conditions.
Finally, a 48V/42A single-output FB-PS-SRC is implemented. Experiments are conducted to verify the theoretical analysis.

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