the A New Soft-Switching Flyback Converter With Coupled Inductors Snubber
A new soft-switching flyback converter with coupled inductors snubber is presented in this paper. The passive snubber circuit, which is composed of two diodes, two capacitors, and two coupled inductor, ensures a zero current turn-on and zero voltage turn-off conditions for the power switch, and alleviates the reverse-recovery problem for the output diode. Moreover, with the proper design of the snubber circuit, the power switch and output diode can be softly switched in a wide load range. The operating principle and performance analysis of the proposed converter are described in detail. The experiment from a 400W prototype has been carried out and the results show that the proposed converter has the advantages of simple structure, low complexity control, and the highest efficiency is more than 95%.
 C.L. Chen and C.J. Tseng, “Passive lossless snubbers for DC/DC converters,” in IEE Proc. Circuits Devices Syst. vol. 145, no. 6, Dec. 1998, pp. 396-401.
 Djordje Garabandic, Miroslave Kuzmanovic and William Dunford, “A low-loss 2D-C-L-R resonant snubber for single-switch soft-switching boost DC/DC converters,” in Proc. IEEE Canadian Conference on Electrical and Computer Engineering, vol. 2, 1998, pp 858–861.
 J. Y. Lee, G. W. Moon, H. J. Park, and M. J. Youn, "integrated zcs quasi-Resonant power factor correction converter based on flyback topology."IEEE trans.power electron. vol. 15, no. 4, pp. 634-643, jul. 2000.
 Tianwen Zhan, Yingchao Zhang, Jintong Nie, Yongchang Zhang and Zhao Zhengming," A Novel Soft-Switching Boost Converter with Magnetically Coupled Resonant Snubber". IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 29, NO. 11, pp.5680-5687 NOV.2014.
]6 [Giorgio Spiazzi, Paolo Mattavelli and Alessandro Costabeber "High Step-Up Ratio Flyback Converter With Active Clamp and Voltage Multiplier, "IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 26, NO. 11, pp.3205-3214, NOVEMBER 2011
]7 [ Alexander Abramovitz, Chih-Sheng Liao, and Keyue Smedley "State-Plane Analysis of Regenerative Snubber for Flyback Converters," IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 28, NO. 11, pp.5323-5332, NOVEMBER 2013
]8 [Amin Emrani, Ehsan Adib, and Hosein Farzanehfard "Single-Switch Soft-Switched Isolated DC–DC Converter, " IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 27, NO. 4, pp. 1952-1957 APRIL 2012
]9[ Ki-Bum Park, Chong-Eun Kim, Gun-Woo Moon, and Myung-Joong Youn "PWM Resonant Single-Switch Isolated Converter, "IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 24, NO. 8, pp. 1876-1886, AUGUST 2009
 E.Adib and H.Farzanehfard, "family of zer o-current transitionpwmConverters,"IEEEtrans.ind.electron.vol.55,no.8,pp.3055-3063,aug.2008.
 P. Das and G. moschopoulos, "a comparative study of zero-current Transition pwm converters," IEEE trans.ind. electron.vol.54, no.3,pp. 1319-1328,mar.2007.
 J. L. Russi, M.L.d.s. martins, L. Schuch, J. R. Pincheiro, and H.L. Hey, " Synthesis methodology for multipole zvt converters," IEEE trans.ind. Electron.vol. 54,no. 3,pp.1783-1795,mar.2007.
 M. Mohammadi and E. Adib, “Reducing Turn Off Losses with a Passive Lossless Snubber for Boost Converter,” The 5th Power Electronics, Drive Systems and Technologies Conference (PEDSTC), pp.385,389, Feb. 2014.
 M. R. Yazdani, H. Farzanehfrad and J. Faiz, “EMI analysis and evaluation of an improved ZCT ﬂyback converter,” IEEE Trans. Power Electron. vol. 26, no. 8, pp. 2326-2334, Aug. 2011.
 G. Hua and F.C. Lee, “Soft-Switching Techniques in PWM Converters,” IEEE Trans. on Industrial Electron. vol.42, no.6, pp.595-603, Dec. 1995.
 E. Adib and H. Farzanehfard, “Family of Zero-Current Transition PWM Converters,” IEEE Trans. on Industrial Electron. vol. 55, no. 8, 3055-3063, 2008.
 W. Huang and G. Moschopoulos, “A New Family of Zero-VoltageTransition PWM Converters With Dual Active Auxiliary Circuits,” IEEE Trans. on Power Electron. vol. 21, no. 2, pp. 370-379, March 2006.
 C. Duarte and I. Barbi, “An Improved Family of ZVS-PWM ActiveClamping DC-to-DC Converters,” IEEE Trans. on Power Electron. vol. 17, no. 1, pp. 1-7, Jan. 2002.
 River T. H. Li and H. S. Chung, “A Passive Lossless Snubber Cell With Minimum Stress and Wide Soft-Switching Range,” IEEE Trans. on Power Electron. vol. 25, no. 7, pp. 1725-1738, Jul. 2010.
 M. Mohammadi and E. Adib, “Lossless Passive Snubber for Half Bridge Interleaved Flyback Converter,” IET Power Electron. Vol. 7, Iss. 6, pp. 1475-1481, Jun. 2014.
 M. Mohammadi, E. Adib and M. R. Yazdani, “Family of SoftSwitching Single-Switch PWM Converters with Lossless Passive Snubber,” IEEE Trans. on Industrial Electron. vol. 62, no. 6, pp. 3473-3481, Jun. 2015.
 M. R. Amini and H. Farzanehfard, “Novel Family of PWM SoftSingle-Switched DCDC Converters With Coupled Inductors,” IEEE Trans. on Industrial Electron. vol. 56, no. 6, pp. 2108-2114, June 2009.
 H. Zhang, Q. Wang, E. Chu, X. Liu and L. Hou, “Analysis and Implementation of A Passive Lossless Soft-Switching Snubber for PWM Inverters,” IEEE Trans. on Power Electron. vol. 26, no. 2, pp. 411-426, Feb. 2011.
 M. Ordonez and J. E. Quaicoe, “Soft-Switching Techniques for Efﬁciency Gains in Full-Bridge Fuel Cell Power Conversion,” IEEE Trans. on Power Electron. vol. 26, no. 2, pp. 482-492, Feb. 2011.