本論文主要為探討非對稱半橋之設計與小信號模型，非對稱半橋主要區分為六個轉換狀態來討論，其中包括兩個傳遞能量狀態、兩個共振狀態，兩個導通暫態本論文均有詳細的推導。系統小訊號分析方面，本文利用狀態空間平均法推導狀態方程式，並以K因子設計補償器，畫出開迴路與閉迴路的波德圖，驗證系統的穩定性。轉換器的動態分析是以IsSpice來模擬。本論文設計並實際做出一台300W之非對稱半橋，其滿載下效率在91%以上，來驗證實際之電路特性符合我們所設計的

Practical point of view in modeling and design considerations for a zero-voltage-switched (ZVS) asymmetrical half-bridge (ASY-HB) converter is proposed. Six dynamic conversion states for describing the converter characteristics are explored and modeled, including two power-delivery states, two resonant states, and two energy-transition states etc. Then a state-space averaging technique is used to describe the state equation. The compensation is implemented by K-factor technique. The Bode diagram of open-loop and closed-loop system are conducted to verify the system stability. The dynamic performance of the proposed converter is simulated by IsSpice. Design considerations are examined thoroughly. A design of 300W ZVS ASY-HB converter is examined and a high efficiency up to 91% at full load is achieved. All performances verified by experiment are quite well and close to the theoretical predictions.

[1] K.H. Liu, R. Oruagnti, and F. C. Lee, “Quasi-resonant converter topologies and characteristics, ” in IEEE Trans. On Power Electronics, vol. 2, pp. 106-116, 1987.
[2] F. C. Lee, “High-frequency quasi-resonant and multi-resonant converter technologies, ” in Proc. IEEE IECON' 88, pp. 509-521, 1988.
[3] D.Maksimovic, S. Cuk, “A general approach to synthesis and analysis of quasi-resonant converters, ” in IEEE PESC, vol. 2, pp.713-727, June 1989.
[4] V. Vorperian, R. Tymerski, Lee, F.C.Y., “Equivalent circuit models for resonant and PWM switches, ” in IEEE, vol. 4, no. 2, pp. 205-214 ,April 1989.
[5] Guichao Hua and Fred C. Lee, “Soft-switching PWM techniques and their applications,” in Proc. EPE’93, pp. 87-92, 1993.
[6] P. Imbertson, N. Mohan, “Asymmetrical duty cycle permits zero switching loss in PWM circuit with no conduction loss penalty,’’ in IEEE Trans. On Industrial Electronics, vol. 29, No. 1,pp 121-125, 1993.
[7] S. Korotkov, V. Meleshin, A. Nemchinov, S. Fraidlin, “Small-signal modeling of soft-switched asymmetrical half-bridge DC/DC converter,’’ in IEEE APEC '95, vol. 2, pp. 707-711, 1995.
[8] S. Korotkov, V. Meleshin, R. Miftahutdinov, S. Fraidlin, “Soft-switched asymmetrical half-bridge DC/DC converter: Steady-state analysis. An analysis of switching processes,’’ in IEEE Telescon '97, pp.177-184, April 22-24,1997.
[9] R. Oruganti, Phua Chee Heng, Guan, J.T.K., Liew Ah Choy, “ Soft-switched DC-DC converter with PWM control,’’ in IEEE INTELEC '93, vol. 1, pp.341-349, 27-30 Sept. 1993.
[10] S. Korotkov, S. Fraidlin, “Calculation of the voltage transfer ratio of the asymmetrical half-bridge DC/DC converter using transformer's windings coupling coefficients,’’ in IEEE PESC 98, vol. 2, pp.1979-1984, 17-22 May 1998.
[11] R. Miftakhutdinov, A. Nemchinov, V. Meleshin, S. Fraidlin, “ Modified asymmetrical ZVS half-bridge DC-DC converter,’’ in IEEE APEC '99, vol. 1, pp. 567-574, 1999.
[12] L. Krupskiy, V. Meleshin, A. Nemchinov, “Unified model of the asymmetrical half-bridge converter for three important topological variations,’’ in IEEE INTELEC '99, 6-9 June 1999.
[13] G. Carli, “Dual modulation using the half-bridge with complementary control,’’ in IEEE APEC '99, vol. 2, pp. 987-993, 14-18 March 1999.
[14] Y. Panov and M. Jovanovic, “Performance evaluation of 70-W two-stage adapters for notebook computers, ’’ in IEEE APEC, vol. 2, pp. 1059-1065, 1999.
[15] S. Abedinpour, R. Liu, G. Fasullo, K. Shenai, “Small-signal analysis of a new asymmetrical half-bridge DC-DC converter, ’’ in IEEE PESC, vol. 2, pp. 843-847, 18-23 June 2000.
[16] J.H. Liang, P.C. Wang, K.C. Huang, Chern-Lin Chen, Yi-Hsin Leu, Tsuo-Mim Chen, “Design optimization for asymmetrical half-bridge converters, ’’ in IEEE APEC 2001, vol. 2, pp. 697-702, 4-8 March 2001.
[17] J. Feng, Y. Hu, W. Chen, W. Chau-Chun, “ZVS analysis of asymmetrical half-bridge converter,’’ in IEEE PESC, vol. 1, pp. 243-247, 17-21 June 2001.
[18] T. Tolle, T. Duerbaum, “Modelling of ZVS transitions in asymmetrical half-bridge PWM converters,’’ in IEEE PESC, vol. 1, pp. 308-313, 17-21 June 2001.
[19] Y.H. Len, C.L. Chen, T.M. Chen, “Analysis and design for asymmetrical half-bridge forward mode converters, ’’ in Proc. IEEE PEDS, vol. 1, pp.126-130, 22-25 Oct. 2001.
[20] J. Feng, Y. Hu, W. Chen, and C.C. Wen, “ZVS analysis of asymmetrical half-bridge converter, ’’ in IEEE PESC 2001, vol. 1, pp. 243-247, 2001.
[21] Y.H. Leu, C.L. Chen, “Analysis and design of two-transformer asymmetrical half-bridge converter,’’ in IEEE PESC, vol. 2, pp. 943-948, 23-27 June 2002.
[22] W. Eberle, Yan-Fei Liu, “A zero voltage switching asymmetrical half-bridge DC-DC converter with unbalanced secondary windings for improved bandwidth,’’ in IEEE PESC, vol. 4, pp.1829-1834, 23-27 June 2002.
[23] X. Xu, A.M. Khambadkone and R. Oruganti, “Analysis and design of an optimized asymmetrical half-bridge DC-DC converter,’’ in IEEE PEDS, vol. 1, pp.120-125, 17-20 Nov. 2003.
[24] T. Hosotani, K. Harada, Y. Ishihara, T. Todaka, “A novel self-excited ZVS half-bridge converter, ’’ in IEEE INTELEC '03, pp. 344-351, 19-23 Oct. 2003.
[25] Y. Xing, L. Huang, X. Cai, S. Sun “A combined front end DC-DC converter, ’’ in IEEE APEC '03, vol. 2, pp.1095-1099, 9-13 Feb. 2003.
[26] X. Xu, A.M. Khambadkone, R. Oruganti, “An a asymmetrical half-bridge DC-DC converter close loop design in frequency domain, ’’ in IEEE PESC 04,vol. 2, pp.1642-1647, 20-25 June 2004.
[27] L. Wonseok, C. Byungcho, Ko Jiemyung, “Current-mode control to enhance closed-loop performance of asymmetrical half-bridge dc-to-dc Converters, ’’ in Proc. IEEE ISCAS '04, vol. 5, pp.896-899, 23-26 May 2004.
[28] S.K. Han, G.W. Moon, M.J. Youn, “A high efficiency ZVS PWM asymmetrical half-bridge converter for plasma display panel sustaining power module, ’’ in IEEE PESC 04, pp. 776-781, 20-25 June 2004.
[29] C. S. Leu, G. Hua and F. C. Lee, “Comparison of forward topologies with various reset schemes,” 1991 VPEC Seminar Proceedings, pp. 101-109.
[30] B. Andreycak, “Active clamp and reset technique enhances forward converter performance,” Unitrode Power Supply Design Seminar SEM-1000, 1994.
[31] D. Dalal, “Design considerations for active clamp and reset technique,” Unitrode Power Supply Design Seminar, SEM-1200,pp. A4-1-A4-23.
[32] P. Vinciarelli, “Optimal resetting of the transformer’s core in singleended forward converter,” U.S. Patent, No. 4,441,146, Apr. 1984.
[33] Ned. Mohan, Tore M. Undeland, and William P. Robbins, “Power electronics converters, applications, and design,” Second edition ,John Wiley & Sons,Inc New York Chichester Brisbane Toronto Singapore.