本論文提出具高效率、高昇壓比之電力轉換器設計，而且使用低耐壓之功率開關、二極體和輸出電容即可達成高的直流輸出電壓。此電路架構包含：能量傳遞電路 (昇壓及返馳轉換器)、突波電壓箝制電路、漏感能量回送到輸出之電路，其功能有如主動式箝制電路，能適當地抑制並傳送功率轉換元件在開路的瞬間所產生之突波高電壓能量至輸出端，以提高電路之整體效率。電路為一綜合昇壓式 (boost) 及返馳式(flyback) 之整合型電力轉換器。電路架構之設計使用耦合電感技術，可以在小的導通責任週期 (duty cycle) 之下即可達成高的輸出電壓增益比值。因此，類似因電路導通責任週期超過50% 而需要之斜坡補償電路設計是可以簡化的，也不會因為過大的導通週期造成電路轉換效率的大幅下降。輸出級設計為昇壓及返馳電力轉換電路輸出電壓之串聯整合，以達到提升輸出電壓之目的。主要功率轉換開關被設p在低電壓端，做能量切換動作，輸出整流二極體以分壓方式配置，也使整流二極體及輸出濾波電容器可以在低耐壓值設計。
　　電路架構之操作原理、分析與設計要點，詳述於論文各章節中，在電感電流為連續導通電流模式時，暫態特性以及穩態分析，是利用電感電壓及電容電流在完整週期操作下能量平衡之原理，及利用小漣波電壓、電流近似之假設而加以討論、分析，並繪圖說明比較特性。
　　文中並以實際之電路製作、實驗，其量測結果與模擬軟體 (IsSpice) 作比較，以印證本文所提之新型電路架構的可行性及正確性。結果證實本文完成之電路特性，在實際應用上確實可以達到高效率、高昇壓比之操作特性。

　This dissertation proposes a high-efficiency high-step-up power converter with low voltage stress on the power switch, power diodes and output capacitors. The circuit topology of the proposed converter consists of an energy clamp circuit and a voltage boost cell. The boost converter functions as an active-clamp circuit to suppress the voltage spike on the power switch during the turn-off transient period. The integrated boost-flyback converter (IBFC) uses coupled-inductor techniques to achieve high-step-up voltage with low duty ratio, and thus the slope compensation circuit is disregarded. The boost converter output terminal and flyback converter output terminal are serially connected to increase the output voltage gain with the coupled inductor. By serially connecting the secondary windings of the boost inductor, a high voltage gain is achieved with less voltage stress on the power devices, such as on the power MOSFET and power diodes.
　The operating principles, theoretical analysis and design methodology of the proposed converter are presented. The voltage gain and efficiency at steady state are derived using the principles of inductor volt-second balance, capacitor charge balance, and the small-ripple approximation for continuous-conduction mode (CCM). A 35W, 12VDC input, 42VDC output, fsw= 38kHz IBFC with simulation and experimental results has been implemented in the laboratory to validate the theoretical analysis. A design procedure is expounded, and design guidelines for selecting critical components are also presented. This dissertation reveals that high voltage gain with high efficiency (nearly 93%) can be achieved by the IBFC system.

[1] R. W. Erickson and D. Maksimović, Fundamentals of Power Electronics. 2nd edition, John Wiley, New York, pp. 39-55, 1950.
[2] Ned Mohan, T. M. Undeland, and W. P. Robbins, Power Electronics, 2nd edition, John Wiley & Sons, Inc. New York, pp. 172-178, 1995.
[3] D. W. Hart, Introduction to Power Electronics. Prentice-Hill, New York, pp. 212–214, 1964.
[4] L. H. Dixon, “Control Loop Cookbook,” Unitrode Power Supply Design Seminar, SEM-1200, pp. C4-1– C4-26, 1997.
[5] Q. Zhao, F. Tao, F. C. Lee, P. Xu and J. Wei, "A Simple and Effective Method to Alleviate the Rectifier Reverse-Recovery Problem in Continuous-Current-Mode Boost Converters Boost Converters," IEEE Trans. on Power Electronics, vol. 16, no. 5, pp. 649-658, September 2001.
[6] J. Wang, W. G. Dunford, and K. Mauch, “A Comparison of Modified Boost Converters with Continuous Inductor Current Mode and Ripple Free Input Current with Conventional Converters,” IEEE Industry Applications Conference, pp. 878-885, 1996.
[7] D. K. W. Cheng, X. C. Liu, and Y. S. Lee, ”A New Improved Boost Converter with Ripple Free Input Current Using Coupled Inductors,” IEE, Power Electronics and Variable Speed Drives, pp. 592-599, 1998.
[8] J. Wang, W. G. Dunford and K. Monrad, “Analysis of a Ripple-Free Input-Current Boost Converter with Discontinuous Conduction Characteristics," IEEE Trans. on Power Electron., vol. 12, pp.684-694, July 1997.
[9] J. Wang, W. Dunford and K. Mauch, “Modified Boost Converter with Continuous Inductor Current Mode and Ripple Free Input Current,” IEEE Power Electronics Specialists Conference, pp.390-396, 1996.
[10] Q. Zhao, F. Tao and F. C. Lee, "A Front-end DC/DC Converter for Network Server Applications," IEEE Power Electronics Specialists Conf., pp. 1535-1539, 2001.
[11] Q. Zhao, Y. Hu, F. C. Lee, J. A. Sabate and F. Li, “A High Efficiency DC/DC Converter as the Front-end stage of High Intensity Discharge Lamp Ballasts for Automobiles,” Power Electronics and Motion Control Conference, vol. 2, pp. 752 -756, 2000.
[12] Q. Zhao, F. Tao, Y. Hu and F. C. Lee, "Active-Clamp DC/DC Converters Using Magnetic Switches," Applied Power Electronics Conference, Annual IEEE, , vol. 2, pp. 946-952, 2001.
[13] E. J. Copple and A. Heights, “High Efficiency DC Step-up Voltage Converter,” U.S. Patent 5 929 614, July 27, 1999.
[14] Y. S. Lee and B. T. Lin, “Adding Active Clamping and Soft Switching to Boost-Flyback Single-Stage Isolated Power-Factor-Corrected Power Supplies,” IEEE Trans. on Power Electron., vol. 12, no. 6, pp.1017-1027, Nov. 1997.
[15] C. M. C. Duarte and I. Barbi, “An Improved Family of ZVS-PWM Active-Clamping DC-to-DC Converters,” IEEE Trans. on Power Electron., vol. 17, no. 1, pp.1-7, Jan. 1997.
[16] S. J. Finney, B. W. Williams and T. C. Green, “RCD Snubber Revisited,” IEEE Trans. on Industrial Applications, vol. 32, pp. 155-160, Jan./Feb. 1996.
[17] R. Watson, G. C. Hua and F. C. Lee, “Characterization of an Active Clamp Flyback Topology for Power Factor Correction Applications,” Proc. IEEE–APEC’94 Conf., pp. 412 –418, 1994.
[18] G. Chen, D. Xu, B. Feng and Y. Wang, “A Family of Compound Active-Clamping DC-DC Converters,” Proc. IEEE–APEC’02 Conf., pp. 850 –856, 2002.
[19] P. Athalye, D. Maksimovic and R. Erickson, “Averaged Switch Modeling of Active-Clamped Converters,” Proc. IEEE–IECON'01 Conf., pp. 1078 –1083, 2001.
[20] C. Ji, K. M. Smith, K. M. Smedley and K. King, "Cross Regulation in Flyback Converters: Analytic Model and Solution," IEEE Trans. Power Electrons., vol. 16, pp. 231-239, March 2001.
[21] S. Ćuk and R. D. Middlebrook, “Coupled-Inductor and Other Extensions of a New Optimum Topology Switching DC-to-DC Converter,” Advances in Switched-Mode Power Conversion, Pasadena, CA:TESLAco, vol. 2, pp 331-347.
[22] S. Lou, W. Qiu, W. Wu and I. Bataresh, “Flyboost Power Factor Correction Cell and Its Applications in Single-Stage AC-DC Converter,” Proc. IEEE-PESC'02 Conf., pp. 1375 –1380, June 2002.
[23] M. Rajeev, “An Input Current Shaper with Boost and Flyback Converter Using Integrated Magnetics,” 5th International conference on Power Electronics and Drive System (PEDS), pp. 327 –331, Nov. 2003.
[24] W. Wu, W. Qiu, K. Rustom, S. Lou and I. Bataresh, “Universal Input Single-Stage PFC AC-DC Converter with Reduced DC-Bus Voltage Stress,” Proc. IEEE-PESC'02 Conf., pp. 1351 –1356, 2002.
[25] W. Qiu, W. Wu, S. Lou, P. Kornetzky and I. Bataresh, “Practical Design Considerations of a Single-stage Single-switch Parallel PFC Converter for Universal Voltage Applications,” Industry Applications Conference, IAS Annual Meeting, pp. 2133 –2140, 2002.
[26] S. Lou, H. Wei, G. Zhu and I. Bataresh, “Several Schemes of Alleviating Bus Voltage Stress in Single-Stage Power Factor Correction Converters,” Proceeding of the IEEE 1999 International Conference on Power Electronics and Drive System(PEDS’99), pp. 921 –926.
[27] D. A. Ruiz-Caballero and I. Barbi, “A New Flyback-Current-Fed Push-Pull DC-DC Converter,” IEEE Trans. on Power Electron., vol. 14, pp.1056-1064, Nov. 1999.
[28] H. Chung, S. Y. R. Hui and W. H. Wang, “An Isolated Fully Soft-Switched Flyback Converter with Low Voltage Stress,” Proc. IEEE-PESC'97 Conf., pp. 1417 –1423, 1997.
[29] J. Xu, “An Analytical Technique for the Analysis of Switching DC-DC Converters,” IEEE International Sympoisum on Circuits and Systems, vol. 2, pp. 1212 –1215, 1991.
[30] M. K. Kazimierczuk and D. Czarkowski, “Application of the Principle of Energy Conservation to Modeling the PWM Converters,” Proc. IEEE–Control Applications Conf., vol. 1, pp. 291–296, 1993.
[31] M. K. Kazimierczuk and S. T. Nguyen, “Small-Signal Analysis of Open-Loop PWM Flyback DC-DC Converter for CCM,” Proc. IEEE–NAECON’95 Conf., pp. 69 –76, 1995.
[32] D. Czarkowski and M. K. Kazimierczuk, “Linear Circuit Models of PWM Flyback and Buck/Boost Converters,” IEEE Trans. on Circuits and Systems I: Fundamental Theory and Applications, vol. 39, pp. 688 –693, Aug. 1992.
[33] R. K. Singh, A. Joshi and A. Ghosh, “A Modified Flyback DC-DC Converter Topology,” Proc. IEEE- APEC'98 Conf., pp. 337 –343, 1998.
[34] P. W. Lee, Y. S. Lee, D. K. W. Cheng and X. C. Liu, “Steady-State Analysis of an Interleaved Boost Converter with Coupled Inductors,” IEEE Trans. on Industrial Electron., vol. 47, pp. 787–795, Aug. 2000.
[35] P. M. Barbosa and I. Barbi, “A Single-Switch Flyback-Current-Fed DC-DC Converter,” IEEE Trans. on Power Electron., vol.13, pp. 466–475, May 1998.
[36] S. Cuk and R. D. Middlebrook, “ A New Optimum Topology Switching dc-dc Converter,” IEEE Power Electronics Specialists Record, pp. 160-179, 1977.
[37] C. Y. Inaba, Y. Konishi and M. Nakaoka, “ High frequency PWM controlled step-up chopper type DC-DC power converters with reduced peak switch voltage stress,” IEE Proc.-Electr. Power Appl., vol. 151, No. 1, pp.47-52, Jan. 2004.