本論文研製一具有漏感能量回收之雙向電源轉換器，電路架構使用錯相式順向返馳式轉換器，並使用兩組變壓器來減少電流峰值，以降低功率元件上的導通損失並提升效率。當電路操作於降壓模式時，電路之特性為錯相式順向返馳式電路，開關最大電壓會被箝位在輸入電壓，並回收變壓器的漏感能量至箝位電容或輸入端。當雙向電路操作於升壓模式時，電路之特性為輸入並聯，輸出串聯之返馳式電路，開關最大電壓亦會被箝位在輸入電壓，並回收變壓器的漏感能量到輸入端。本文先對於所提出之轉換器電路，分析雙向電能轉換之動作原理及穩態特性。最後，實作一雙向轉換器，高低電壓分別為200 V/24 V，最大功率為500 W之電路，以驗證所提架構之可行性，降壓和升壓模式最高效率分別為95.5 %與92.3 %。

In this thesis, a bidirectional interleaved forward-flyback DC-DC converter with leakage energy recycled is proposed. The proposed converter uses two transformers to reduce the current stress on the power components to reduce the conduction loss and improve the efficiency. When the proposed converter is operated in step-down stage, the topology is the interleaved forward-flyback converter. The voltage stress on power switches is clamped at the input voltage and the leakage energy of the transformer is recycled to the clamping capacitor and input voltage source. When the converter is operated in step-up stage, two flyback converters are operated in parallel and in series in input side and output side, respectively. The voltage stress of power switches is clamped at input voltage and the leakage energy of the transformer is recycled back to input voltage source. Finally, a laboratory prototype circuit with 200 V/24 V and output power 500 W is implemented to verify the feasibility of the proposed converter, the highest efficiency in step-up and step-down are 95.5 % and 92.3 %, respectively.

Chapter 1 Introduction 1
1.1 Background and Motivation 1
1.2 Organization 3
Chapter 2 Introduction of Bidirectional DC-DC Converter 4
2.1 Nonisolated Bidirectional DC-DC Converter 5
2.1.1 Bidirectional Buck/Boost DC-DC Converter 5
2.1.2 Bidirectional Cascode DC-DC Converter 6
2.1.3 Bidirectional Coupled-inductor DC-DC Converter 7
2.2 Isolated Bidirectional DC-DC Converter 8
2.2.1 Bidirectional Flyback DC-DC Converter 8
2.2.2 Bidirectional Half-Bridge/Push-Pull DC-DC Converter 9
2.2.3 Bidirectional Full-Bridge/Full-Bridge DC-DC Converter 10
2.2.4 Bidirectional Forward/Flyback DC-DC Converter 11
Chapter 3 Analysis and Parameters Design of the Proposed Forward/Flyback Bidirectional Converter 13
3.1. Introduction of the Proposed Biderational Converter 13
3.2 Analysis of Proposed Converter in Step-down Stage 16
3.2.1 Operational Principle in Step-down Stage 16
3.2.2 Steady-State Analysis in Step-down Stage 28
3.3 Analysis of Proposed Converter in Step-up Stage 34
3.3.1 Analysis of Proposed Converter in Step-up Stage 34
3.3.2 Steady-State Analysis in Step-up Stage 40
Chapter 4 Hardware Implementation and Experimental Results 44
4.1. Main Topology and Specifications of Proposed Converter 44
4.2. Key Components Selection and Parameters Design 45
4.3. Experimental Results and Discussions 49
4.3.1 Experimental Results and Discussions in Step-down Stage 50
4.3.2 Experimental Results and Discussions in Step-up Stage 60
Chapter 5 Conclusions and Future Works 70
5.1 Conclusions 70
5.2 Future Works 71
References 72

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