本論文提出一具無損耗緩振電路與輸出電壓偵測機制之自激返馳型非接觸式電源供應器。自激返馳型轉換器因具有電路架構簡單及成本低廉等優點，故被廣泛地應用在非接觸式電源供應器中。然而，儲存於變壓器漏感中的能量會於開關截止瞬間產生高壓突波於開關元件上，導致轉換效率降低。因此，於自激返馳型轉換器加入無損耗緩振電路以解決上述缺點。
此外，在非接觸式電源供應器之變壓器結構中，一次側繞組與二次側繞組為分離型式。因此，須採用隔離型式之輸出電壓偵測機制以達到負載調節之目的。
茲將無損耗緩振電路與輸出電壓偵測機制結合以簡化電路。並將此結合電路加入自激返馳型轉換器中，以降低開關元件耐壓、提升轉換效率及具有負載調節之性能。
最後，實做一15 W的具無損耗緩振電路與輸出電壓偵測機制之自激返馳型非接觸式電源供應器，以驗證本論文所提出之電路特性，諸如降低開關電壓應力、提升輸出電壓及改善轉換效率等。

This thesis presents a self-oscillating flyback converter with the proposed voltage-sensing snubber network, whose auxiliary winding is utilized as the lossless snubber inductor and output-voltage sensing winding.
For contactless power supplies, the self-oscillating flyback converter provides a cost-effective solution. However, the energy stored in the leakage inductor causes high voltage spike on the switch, and then leads to low conversion efficiency. Therefore, the concept of the lossless snubber is adopted in order to overcome this drawback. Furthermore, in the contactless power supplies, the secondary side of the transformer is isolated from the primary side. Thus, the isolated voltage-feedback scheme is required. The concept of the isolated output-voltage sensing circuit is applicable for the contactless power supply applications to regulate the output voltage. For simplification, the lossless snubber and the output-voltage sensing winding can be combined together as a single winding.
A prototype circuit of the 15W self-oscillating flyback converter with the proposed voltage-sensing snubber network is built to verify the performances, such as the voltage stress on the switch, the conversion efficiency, and load regulation.

[1] Y. Jang and M. M. Jovanović, “A contactless electrical energy transmission system for portable-telephone battery chargers,” IEEE Trans. Ind. Electron., vol. 50, no. 3, pp. 520-526, Jun. 2003.
[2] K. W. E. Cheng and Y. Lu, “Development of a contactless power converter,” in Proc. Int. Conf. Industrial Technology, 2002, vol.2, pp. 786-791.
[3] A. Okuno, L. Gamage, and M. Nakaoka, “Performance evaluations of high-frequency inverter-linked DC/DC converter with noncontact pickup coil,” IEEE Trans. Ind. Electron., vol. 48, no. 2, pp. 475-477, Apr. 2001.
[4] H. Abe, H. Sakamoto, and K. Harada, “A noncontact charger using a resonant converter with parallel capacitor of the secondary coil,” IEEE Trans. Ind. Appl., vol. 36, no. 2, pp. 444-451, Mar./Apr. 2000.
[5] G. A. Covic, G. Elliott, O. H. Stielau, R. M. Green, and J. T. Boys,“The design of a contact-less energy transfer system for a people mover system,” in Proc. Int. Conf. Power System Technology, Dec. 2000, vol. 1, pp. 79-84.
[6] J. T. Boys, G. A. Covic, and A.W. Green, “Stability and control of inductively coupled power transfer systems,” in Proc. IEE-Elect. Power Appl., vol. 147, no. 1, pp. 37-43, Jan. 2000.
[7] A. Abrial, J. Bouvier, M. Renaudin, P. Senn, and P. Vivet, “A new contactless smart card IC using an on-chip antenna and an asynchronous microcontroller,” IEEE J. Solid-State Circuits, vol. 36, no. 7, pp.1101-1107, Jul. 2001.
[8] H. Sakamoto and K. Harada, “A novel converter for noncontact charging with electromagnetic coupling,” IEEE Trans. Magn., vol. 29, no. 6, pp.3228-3230, Jun. 1993.
[9] C. G. Kim, D. H. Seo, J. S. You, J. H. Park, and B. H. Cho, “Design of a contactless battery charger for cellular phone,” IEEE Trans. Ind. Electron., vol. 48, no. 6, pp. 1238-1247, Dec. 2001.
[10] D. A. G. Pedder, A. D. Brown, and J. A. Skinner, “A contactless electrical energy transmission system,” IEEE Trans. Ind. Electron., vol. 46, pp. 23-30, Feb. 1999.
[11] B. T. Irving and M. M. Jovanović, “Analysis and design of self-oscillating flyback converter”, IEEE Appl. Power Electronics Conf., 2002, pp.897-903.
[12] B. Choi, J. Nho, H. Cha, T. Ahn, and S. Choi, “Design and implementation of low-profile contactless battery charger using planar printed circuit board windings as energy transfer device,” IEEE Trans. Ind. Electron., vol. 51, no. 1, pp. 140-147, Feb. 2004.
[13] S. J. Finney, B. W. Williams, and T. C. Green, “RCD snubber revisited,” IEEE Trans. Ind. Appl., vol. 32, no. 1, pp. 155-160, 1996.
[14] A. Hren, J. Korelic, and M. Milanovic, “RC-RCD clamp circuit for ringing losses reduction in a flyback converter,” IEEE Trans. Circuits Syst., vol. 53, no. 5, pp. 369-373, May 2006.
[15] T. H. Ai, Integrated AC/DC converters with power factor correction and nondissipative snubber, Ph.D. dissertation, National Cheng Kung University, Jul. 2002.
[16] T. Ninomiya, T. Tanaka, and K. Harada, “Analysis and optimization of a nondissipative LC turn-off snubber,” IEEE Trans. Power Electron., vol. 3, no. 2, pp. 147-156, Apr. 1988.
[17] T. H. Ai, “A novel integrated nondissipative snubber for flyback converter,” in Proc. IEEE Int. Conf. Systems & Signals, 2005, pp. 66-71.
[18] C. S. Liao and K. M. Smedley, “Design of high efficiency flyback converter with energy regenerative snubber,” in Proc. IEEE Appl. Power Electronics Conf. and Exp., 2008, pp. 796-800.
[19] J. R. Qian and D. F. Weng, “Leakage energy recovering system and method for flyback converter,” U.S. Patent 6473318 B1, Oct. 29, 2002.
[20] G. Chryssis, High-frequency switching power supplies: theory and design, 2nd edition, McGraw-Hill Companies, New York, 1989.
[21] G. Seragnoil, “Self-oscillating switching power supply with output voltage regulated from the primary side,” U.S. Patent 5699237, Dec. 16, 1997.
[22] Vishay Siliconix, “IRF 820A: Power MOSFET,” Jul. 2008.