本論文提出一種高轉換比快速能量轉換的雙向直流-直流轉換器。與傳統切換式電感轉換器相比，此轉換器使用兩種不同的工作週期來控制切換式電感，使開關不必操作在高工作週期的狀態下達到高電壓增益。此轉換器在轉態模式下加入電容使之與耦合電感串聯諧振來達到快速能量轉換的功能。
本論文將討論升壓模式與降壓模式之動作原理和轉態模式之操作，接著介紹穩態分析。最後實作一規格為48V/400V，功率1kW之雙向電路。升壓模式下最高效率為91.77%，降壓模式則為88.04%，在滿載條件下雙向能量轉換都可以在兩個週期內完成。提出之轉換器特點為高轉換比及快速能量轉換，可應用於儲能系統與直流匯流排中。

In this thesis, a high gain DC-DC converter with fast power transition is proposed. Compared with the conventional switched inductor converter, the converter uses two different duty cycle to control switched-inductor, which can achieve high voltage gain without the switches operating at high duty cycle. The proposed converter adds a resonant capacitor to resonate in series with the coupled inductor in the transient time of transition to achieve fast power conversion.
This thesis will discuss the operation principle of step-up mode, step-down mode, and transient time of transition, and then introduce the steady state analysis. Finally, a 48V/400V, power 1kW circuit is implemented. The maximum efficiency in step-up mode is 91.77%, while in step-down mode is 88.04%, the power transition between both sides can be completed in two cycles under full load conditions. The proposed converter is characterized by high conversion ratio and fast transition, it can be applied to the battery and DC bus in the energy storage system.

REFERENCES
[1]. W. Chen, X. Wu, L. Yao, W. Jiang, and R. Hu, "A Step-up Resonant Converter for Grid-Connected Renewable Energy Sources," in IEEE Transactions on Power Electronics, vol. 30, no. 6, pp. 3017-3029, June 2015.
[2]. H. Liu, H. Hu, H. Wu, Y. Xing, and I. Batarseh, "Overview of High-Step-Up Coupled-Inductor Boost Converters," in IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 4, no. 2, pp. 689-704, June 2016.
[3]. J. Hu, Y. Xu, K. W. Cheng, and J. M. Guerrero, “A Model Predictive Control Strategy of PV-Battery Microgrid under Variable Power Generations and Load Conditions,” Appl. Energy, vol. 221, pp. 195–203, July 2018.
[4]. A. Torkan and M. Ehsani, "A Novel Nonisolated Z-Source DC–DC Converter for Photovoltaic Applications," in IEEE Transactions on Industry Applications, vol. 54, no. 5, pp. 4574-4583, Sept.-Oct. 2018.
[5]. Z. Liang, R. Guo, J. Li, and A. Q. Huang, "A High-Efficiency PV Module-Integrated DC/DC Converter for PV Energy Harvest in FREEDM Systems," in IEEE Transactions on Power Electronics, vol. 26, no. 3, pp. 897-909, March 2011.
[6]. K. Fischer, "Reliability of Power Converters in Wind Turbines: Exploratory Analysis of Failure and Operating Data From a Worldwide Turbine Fleet," in IEEE Transactions on Power Electronics, vol. 34, no. 7, pp. 6332-6344, July 2019.
[7]. R. Barrera-Cardenas and M. Molinas, "Comparative Study of Wind Turbine Power Converters Based on Medium-Frequency AC-Link for Offshore DC-Grids," in IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 3, no. 2, pp. 525-541, June 2015.
[8]. M. Fu, C. Fei, Y. Yang, Q. Li, and F. C. Lee, "Optimal Design of Planar Magnetic Components for a Two-Stage GaN-Based DC–DC Converter," in IEEE Transactions on Power Electronics, vol. 34, no. 4, pp. 3329-3338, April 2019.
[9]. H. Wu, Y. Jia, F. Yang, L. Zhu, and Y. Xing, "Two-Stage Isolated Bidirectional DC–AC Converters With Three-Port Converters and Two DC Buses," in IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 8, no. 4, pp. 4428-4439, Dec. 2020.
[10]. L. An and D. D. Lu, "Analysis of DC Bus Capacitor Current Ripple Reduction in Basic DC/DC Cascaded Two-Stage Power Converters," in IEEE Transactions on Industrial Electronics, vol. 63, no. 12, pp. 7467-7477, Dec. 2016.
[11]. S. Xiong, S. Wong, S. Tan, and C. K. Tse, "A Family of Exponential Step-Down Switched-Capacitor Converters and Their Applications in Two-Stage Converters," in IEEE Transactions on Power Electronics, vol. 29, no. 4, pp. 1870-1880, April 2014.
[12]. P. Thummala, D. Maksimovic, Z. Zhang, and M. A. E. Andersen, "Digital Control of a High-Voltage (2.5 kV) Bidirectional DC--DC Flyback Converter for Driving a Capacitive Incremental Actuator," in IEEE Transactions on Power Electronics, vol. 31, no. 12, pp. 8500-8516, Dec. 2016.
[13]. H. S. Chung, Wai-Leung Cheung, and K. S. Tang, "A ZCS bidirectional flyback DC/DC converter," in IEEE Transactions on Power Electronics, vol. 19, no. 6, pp. 1426-1434, Nov. 2004.
[14]. G. Chen, Y. S. Lee, S. Y. R. Hui, D. Xu, and Y. S. Wang, "Actively clamped bidirectional flyback converter," in IEEE Transactions on Industrial Electronics, vol. 47, no. 4, pp. 770-779, Aug. 2000.
[15]. K. Xiangli, S. Li, and K. M. Smedley, "Decoupled PWM Plus Phase-Shift Control for a Dual-Half-Bridge Bidirectional DC–DC Converter," in IEEE Transactions on Power Electronics, vol. 33, no. 8, pp. 7203-7213, Aug. 2018.
[16]. H. Shi, K. Sun, H. Wu, Y. Li, and X. Xiao, "Unified state-space modeling method for dual-active-bridge converters considering bidirectional phase shift," 2018 IEEE Energy Conversion Congress and Exposition (ECCE), 2018, pp. 643-649.
[17]. G. Chen, Y. Deng, H. Peng, X. He, and Y. Wang, "An optimized modulation method tor full-bridge/push-pull bi-directional DC-DC converter with wide-range ZVS and reduced spike voltage," IECON 2014 - 40th Annual Conference of the IEEE Industrial Electronics Society, 2014, pp. 1247-1253.
[18]. K. Yamamoto, E. Hiraki, T. Tanaka, M. Nakaoka, and T. Mishima, "Bidirectional DC-DC converter with full-bridge / push-pull circuit for automobile electric power systems," 2006 37th IEEE Power Electronics Specialists Conference, 2006, pp. 1-5.
[19]. Y. X. Wang, F. F. Qin, and Y. B. Kim, “Bidirectional DC-DC converter design and implementation for lithium-ion battery application,” in 2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC), Dec 2014, pp. 1–5.
[20]. L. Yang and T. Liang, "Analysis and Implementation of a Novel Bidirectional DC–DC Converter," in IEEE Transactions on Industrial Electronics, vol. 59, no. 1, pp. 422-434, Jan. 2012.
[21]. M. Lakshmi and S. Hemamalini, "Nonisolated High Gain DC–DC Converter for DC Microgrids," in IEEE Transactions on Industrial Electronics, vol. 65, no. 2, pp. 1205-1212, Feb. 2018.