本論文提出一具耦合電感之新型高轉換比雙向直流-直流轉換器，利用耦合電感於開關切換時二次側極性相反的特性，升壓模式中，二次側雙電容為並聯充電、串聯放電，轉換器操作於適當責任週期下，即可達到高升壓比，而一次側箝位電路更可有效降低主開關之電壓應力，因此可採用低導通阻抗之開關降低導通損；降壓模式中，二次側雙電容為串聯充電、並聯放電，因此能達到高降壓比，此外，降壓時雙開關和雙電容可視為兩組主動箝位電路，使開關達到零電壓切換，有效降低切換損，轉換器具有高效率及元件少等特色，本文首先提出此雙向轉換器之動作原理與穩態特性分析，最後實作一組轉換電壓24 V/400 V，功率200 W之雛型電路，以驗證本論文中所提雙向轉換器之可行性。

In this thesis, a novel high conversion ratio bidirectional DC-DC converter with coupled-inductor technique is proposed. In boost mode, two capacitors are parallel charged and series discharged by the coupled-inductor. Thus, high step-up voltage gain can be achieved with an appropriate duty ratio. The voltage stress on the main switch is reduced by a clamp circuit. Therefore, low resistance RDS(ON) of the main switch can be adopted to reduce conduction loss. In buck mode, two capacitors are series charged and parallel discharged by coupled-inductor. The high step-down gain is achieved. Besides, all of the switches are zero voltage-switching (ZVS) turned on and the switching loss can be improved. Due to two active clamp circuits, The efficiency can be further improved. The operating principle and steady-state analyses of the voltage gain are discussed. Finally, a 24-V input voltage, 400-V output voltage, and 200-W output power prototype circuit is implemented in the laboratory to verify the performance.

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