本論文提出一種混合式切換技術配合主動式箝位電路或半橋電路，應用在返馳式轉換器以提高轉換器零電壓切換之範圍、輸出二極體有零電流導通的優點。轉換器的切換損失最小化，進而達到輕薄短小、高效率之次世代產品的需求。此技術在電路上不需其它額外元件，且控制簡單為定頻的脈波寬度調變。混合切換技術就是在一切換週期內結合了傳統脈波寬度調變的線性電感電流與諧振電路的諧振電感電流，也就是說在傳統的定頻的脈波寬度調變控制的轉換器加入諧振的元素，且同時保留了定頻的脈波寬度調變轉換器和諧振電路之優點。論文首先介紹混合切換技術，並對此技術進行了詳細的分析，接下來將此技術應用在三種不同的拓撲上以提高轉換器整體的性能。其一為主動式箝位返馳式轉換器結合混合切換技術，首先對轉換器進行詳細的分析，並對其開關零電壓切換、輸出二極體零電流切換的條件及工作週期的損失進行研究。其二為主動式箝位SEPIC結合混合式切換技術，SEPIC其輸入為連續電流傳導性的電磁干擾相對較低，但其輸入電感大大的影響了開關零電壓切換之範圍，所以針對了輸入電感對開關零電壓切換條件做了詳細的討論，且此轉換器同樣保持了輸出二極體零電流切換及最小工作週期的損失。其三為非對稱半橋返馳式轉換器結合混合式切換技術，其電壓轉換比適合低壓輸出的應用，於開關零電壓切換和輸出二極體的零電流切換條件做了詳細的研究。此切換技術不需在原拓撲加入額外的元件，且控制為定頻脈波寬度變，所以控制簡單、可靠度較高。
最後，以實驗的結果證明三種拓撲結合了混合式切換技術電路的可行性，再對三種拓撲結合所提出的切換技術與傳統拓撲之間做出一些比較，以驗證其實用性和突出的性能改進。

This dissertation proposes a hybrid-switching technique for active-clamp circuit or half bridge circuit that can be applied to the flyback converter in order to increase the range of zero-voltage-switching (ZVS), and enables the output diode to operate in zero-current-switching (ZCS) and minimizing the switching loss. Given the high efficiency and high power density requirements of the switch-mode power supply, the proposed technique is an attractive design for future off-line applications. Design considerations are very simple because the converter still operates at a fixed frequency and no extra components are need. The hybrid-switching technique incorporates resonant operation into a conventional pulse-width modulation (PWM) circuit in a single switching cycle, while preserving the merits of both PWM and resonant operations.
First, the hybrid-switching technique is introduced and analyzed, then the proposed technique is integrated into three different topologies in order to improve the converters’ performance. One of the converters is the hybrid-switching active-clamp flyback converter. The detailed analysis and design are described, then the ZVS condition of the MOSFETs, the ZCS condition of output diode, and duty cycle are studied. Next, there is the hybrid-switching active-clamp integrated single-ended primary-inductor converter (SEPIC). The input current of SEPIC is continuous, therefore there are good electromagnetic interference (EMI) features. However, the range of ZVS operation is highly dependent on the input inductor, therefore, a detail analysis will be given regarding the relationship between input inductance and range of the ZVS operation. This converter still preserves the ZCS turn-off operation of the output diode and the minimized duty loss. Lastly, a hybrid-switching asymmetric half-bridge flyback is studied for low-voltage output applications. The ZVS condition of the MOSFETs and ZCS condition of the output diode are studied. The introduction of this technique does not require the addition of components into the original topology. Furthermore, the control scheme is fixed frequency PWM, therefore, the control is simple and straight forward, while still being highly reliable.
The experimental results of the three topologies after integrating the proposed technique are presented. Finally, the performance between the proposed converter and the conventional converter are compared to verify the practicality of each approach and highlight the improved performance.

[1] J. Robereg, “A low-power high-efficiency DC-to-DC converter,” IEEE International Solid-State Circuits Conf., Digest of Technical Papers, Feb. 1965, pp. 72-73.
[2] N. R. M. Rao, “Switched-mode power supply,” U.S. Patent 4 253 137, Feb. 24, 1981.
[3] R. D. W. Shelly, “Rectifier-converter power supply with mult-channel flyback inverter,” U.S. Patent 4 302 803, Nov. 24, 1981.
[4] K. Becker, “Self oscillating, single-ended flyback converter with input voltage responsive control,” U.S. Patent 4 504 775, Mar. 12, 1985.
[5] R. C. Ray, “Buck-boost converter with dual-mode control for battery charging,” U.S. Patent 4 536 696, Aug. 20, 1985.
[6] V. G. Bello, and C. W. Sweeting, “Flyback feedforward pulse width modulation regulator,” U.S. Patent 4 546 421, Oct. 8, 1985.
[7] O. K. Nilssen, “MOSFET flyback converter,” U.S. Patent 4 882 663, Nov. 21, 1989.
[8] T. Matsumura, “Transformer for a flyback type converter,” U.S. Patent 4 887 061, Dec. 12, 1989.
[9] W. F. Santelmann, Jr., “Method of and apparatus for efficient high voltage generation by resonant flyback” U.S. Patent 4 616 300, Oct. 7, 1986.
[10] R. B. Ridley, A. Lotfi, V. Vorperian, and F. C. Lee “Design and control of a full-wave, quasi-resonant flyback converter,” in Applied Power Electronics Conf. and Exposition, New Orleans, LA, 1988, pp. 41-49.
[11] F. C. Lee, “High-frequency quasi-resonant and multi-resonant converter technologies,” in Ind. Electronics Soc. Annual Conf., Singapore, 1988, pp. 509-521.
[12] K. H. Liu, and F. C. Lee, “Zero-voltage switching technique in DC/DC converter, ” IEEE Trans. Power Electron., vol. 5, no. 3, pp. 293-304, Jul. 1990.
[13] K. Yoshida, T. Ishii, and N. Nagagata, “Zero voltage switching approach for flyback converter, ” in Telecommunications Energy Conf., Washington, DC, 1992, pp. 324-329.
[14] G. Hua, C. S. Leu, Y. Jiang, and F. C. Lee, “Novel zero-voltage-transition PWM converters,” IEEE Trans. Power Electron., vol. 9, no. 2, pp. 213-219, Mar. 1994.
[15] W. Dong, Q. Zhao, J. Liu, and F. C. Lee, “A boost converter with lossless snubber under minimum voltage stress,” in Applied Power Electronics Conf. and Exposition, 2002, vol. 1, pp. 509-515.
[16] K. B. Park, G. W. Moon, and M. J. Youn, “Nonisolated high step-up boost converter integrated with Sepic converter,” IEEE Trans. Power Electron., vol. 25, no. 9, pp. 2266-2275, Sep. 2010.
[17] J. A. Bassett, “DC/DC converter switching at zero voltage,” U.S. Patent 4 959 763, Sep. 25, 1990.
[18] C. P. Henze, D. S. Lo, and H. C. Martin, Jr., “Zero-voltage resonant transition switching power converter,” U.S. Patent 5 057 986, Oct. 15, 1991.
[19] T. Ishii, and T. Maeoka, “Flyback converter switching power supply device,” U.S. Patent 5 146 394, Sep. 8, 1992.
[20] G. C. Hua, W. A. Tabisz, C. S. Leu, and N. Dai, “Development of a DC distributed power system,” in Applied Power Electronics Conf. and Exposition, 1994, vol. 2, pp. 763-769.
[21] R. L. Steigerwald, “A comparison of half-bridge resonant converter topologies,” IEEE Trans. Power Electron., Vol. 3, Issue 2, pp.174–182, Apr. 1998.
[22] D. Temkin, U. Carlsson, and G. Dakermanji, “Development of a multiple output resonant converter for space applications,” in Applied Power Electronics Conf. and Exposition, 1988, vol. 2, pp. 167-181.
[23] K. AI. Haddad, A. Bellahnid, V. Rajagopalan, Y. Cheron, and H. Foch, “Novel control strategy to improve the dynamic performance of a series resonant converter,” in Ind. Applications Soc. Annual Meeting, Pittsburgh, PA, 1988, pp. 806-812.
[24] Y. Ohashi, Y. Kuwata, and K. Mizuguti, “A 100 kHz, 2.7k W rectifier using a series-resonant converter bypassing discharge current,” in Telecommunications Energy Conf., Florence, 1989, pp. 16.5/1-16.5/7.
[25] S. Sooksatra, and C. Q. Lee, “Current driven series resonant converter,” in Applied Power Electronics Conf. and Exposition, 1990, vol. 2, pp. 128-136.
[26] A. Ghahary, and B. H. Cho, “Design of a transcutaneous energy transmission system using a series resonant converter,” in Power Electronics Specialists Conf., US, 1990, pp. 1–8.
[27] W. M. Moussa, and J. E. Morris, “Steady state analysis for an off-line series resonant converter,” in Southern Tier Technical Conf., US, 1990, pp. 23–29.
[28] S. Sooksatra, and C. Q. Lee, “Non-resonant coupled parallel resonant converter,” in Symposium on Circuits and Systems, Champaign, IL, pp. 781-784.
[29] I. Batarseh, and C. Q. Lee, “High-frequency high-order parallel resonant converter,” IEEE Trans. Ind. Electron., vol. 36, no. 4, pp. 1708-1716, Nov. 1989.
[30] C. Q. Lee, and S. Sooksatra, “Current programmed control nonresonant coupled parallel resonant converter,” in Power Electronics and Variable-Speed Drives Conf., London, 1990, pp. 142–147.
[31] M. Nakaoka, and L. Ding, “The state-of-the art high-frequency phase-shifted PWM resonant converter utilizing parasitic circuit components of high-voltage transformer and feeding cable,” in Power Electronics and Variable-Speed Drives Conf., London, 1990, pp. 148–155.
[32] Y. Kuwata, Y. Ohashi, and K. Yotsumoto, “Characteristics of a new series-resonant converter with a parallel resonant circuit,” in Telecommunications Energy Conf., Sweden, 1987, pp. 204-210.
[33] M. Emsermann, “An approximate steady state and small signal analysis of the parallel resonant converter running above resonance,” in Power Electronics and Variable-Speed Drives Conf., London, 1990, pp. 9-14.
[34] R. Liu, and C. Q. Lee, “The LLC-type series resonant converter-variable switching frequency control,” in Symposium on Circuits and Systems, Champaign, IL, pp. 509-512.
[35] A. K. S. Bhat, “Analysis and design of LCL-type series resonant converter,” in Telecommunications Energy Conf., Orlando, FL, 1990, pp. 172-178.
[36] H. de Groot, E. Janssen, R. Pagano and K. Schetters, “Design of 1-MHz LLC resonant converter based on a DSP-driven SOI half-bridge power MOS module,” IEEE Trans. Power Electron., vol. 22, no. 6, pp. 2307-2320, Nov. 2007.
[37] Z, Fang, S. Duan, C. Chen, X. Chen, and J. Zhang, “Optimal design method for LLC resonant converter with wide range output voltage,” in Applied Power Electronics Conf. and Exposition, 2013, pp. 2106-2111.
[38] L. Hang, S. Wang, Y. Gu, W. Yao, and Z. Lu, “High cross-regulation multioutput LLC series resonant converter with magamp postregulator,” IEEE Trans. Ind. Electron., vol. 58, no. 9, pp. 3905-3913, Sep. 2011.
[39] R. Yu, G. K. Y. Ho, B. M. H. Pong, B. W. K. Ling, and J. Lam, “Computer-aided design and optimization of high-efficiency LLC series resonant converter,” IEEE Trans. Power Electron., vol. 27, no. 7, pp. 3243-3256, Jul. 2012.
[40] H. Hu, X. Fang, F. Chen, Z. J. Shen, and I. Batarseh, “A modified high-efficiency LLC converter with two transformers for wide input-voltage range application,” IEEE Trans. Power Electron., vol. 28, no. 4, pp. 1946-1960, Apr. 2013.
[41] M. Yu, D. Sha, Z. Guo, and X. Liao, “Hybrid PS full bridge and LLC half bridge DC-DC converter for low-voltage and high-current output applications,” in Applied Power Electronics Conf. and Exposition, 2014, pp. 1088-1094.
[42] B. Gu, C. Y. Lin, B. F. Chen, J. Dominic and J. S. (Jason) Lai, “Zero-voltage-switching PWM resonant full-bridge converter with minimized circulating losses and minimal voltage stresses of bridge rectifiers for electric vehicle battery chargers,” IEEE Trans. Ind. Electron., vol. 28, no. 10, pp. 4657-4667, Oct. 2013.
[43] B. Gu, J. S. Lai, N. Kees and C. Zheng, “Hybrid-switching full-bridge DC-DC converter with minimal voltage stress of bridge rectifier, reduced circulating losses, and filter requirement for electric vehicle battery chargers,” IEEE Trans. Ind. Electron., vol. 28, no. 3, pp. 1132-1144, Mar. 2013.
[44] B. Gu, J. Dominic, J. S. Lai and H. B. Ma, “Hybrid transformer ZVS/ZCS DC-DC converter for photovoltaic microinverters,” in Applied Power Electronics Conf. and Exposition, 2013, pp. 16-22.
[45] B. Gu, J. Dominic, J. S. Lai, Z. Zhao and C. Liu, “High boost ratio hybrid transformer DC-DC converter for photovoltaic module applications,” in Applied Power Electronics Conf. and Exposition, 2012, pp. 598-606.
[46] S. Cuk, “Step-down converter having a resonant inductor, a resonant capacitor and a hybrid transformer,” U.S Patent 7915874, Mar. 2011.
[47] S. Cuk and Z. Zhang, “Voltage step-up switching DC-to-DC converter field of the invention,” U.S Patent 7778046, Aug. 2010.
[48] P. Athalye, D. Maksimovic and R. Erickson, “Averaged switch modeling of active-clamped converters,” in Industrial Electronics Society Conf., 2001, vol. 2, pp. 1078-1083.
[49] Praneet Athalye, Dragan Maksimovic and Robert Erickson, “High-performance front-end converter for avionics applications,” IEEE Trans. on Aerospace and Electronic Systems., vol. 39, no. 2, pp. 462-470, Apr. 2003.
[50] P. Athalye, D. Maksimovic and R. Erickson, “Improving efficiency of the active-clamped SEPIC rectifier at high line frequencies,” in Applied Power Electronics Conf. and Exposition, 2005, vol. 2, pp. 1152-1157.
[51] S. Buso, G. Spiazzi, and F. Sichirollo, “Study of the asymmetrical half bridge flyback converter as an effective line fed solid state lamp driver,” IEEE Trans. Ind. Electron., vol. 28, no. 99, pp. 4657-4667, Mar. 2014.
[52] H. S. Kim, J. H. Jung, J. W. Baek, and H. J. Kim, “Ananlysis and design of a multioutput converter using asymmetrical PWM half-bridge flyback converter employing a parallel-series tranformer,” IEEE Trans. Ind. Electron., vol. 60, no. 8, pp. 3115-3125, Aug. 2013.
[53] J. H. Jung, “Feed-forward compensator of operating frequency for APWM HB flyback converter,” IEEE Trans. Power Electron., vol. 27, no. 1, pp. 211-223, Jan. 2012.