13 High Efficiency And High Power Factor Single Stage
High efficiency and high power factor single-stage balanced forward-flyback converter
Yoon Choi, Moon-Hwan Keum, and Sang-Kyoo Han†
Jeong-il Kang
Power Electronics System Laboratory, POESLA
Kookmin University
Seoul, 136-702, Republic of Korea
E-mail : †djhan@kookmin.ac.kr
Visual Display, R&D Team
Samsung Electronics. Co. Ltd.
Suwon, Republic of Korea
E-mail : jeongil.kang@samsung.com
Abstract— In this paper, a high efficiency and high power factor single-stage balanced forward-flyback converter merging a foward and flyback converter topologies is proposed. The conventional AC/DC flyback converter can achieve a good power factor but it has a high offset current through the transformer magnetizing inductor, which results in a large core loss and low power conversion efficiency. And, the conventional forward converter can achieve the good power conversion efficiency with the aid of the low core loss but the input current dead zone near zero cross AC input voltage deteriorates the power factor. On the other hand, since the proposed converter can operate as the forward and flyback converters during switch on and off periods, respectively, it cannot only perform the power transfer during an entire switching period but also achieve the high power factor due to the flyback operation. Moreover, since the current balanced capacitor can minimize the offset current through the transformer magnetizing inductor regardless of the AC input voltage, the core loss and volume of the transformer can be minimized. Therefore, the proposed converter features a high efficiency and high power factor. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a prototype of 24W LED driver are presented.
between AC input and DC output. Even though the two-stage configuration can provide the high power factor, good output regulation and excellent ripple voltage, it has several significant disadvantages such as a large system size, high cost
of
Yoon Choi, Moon-Hwan Keum, and Sang-Kyoo Han†
Jeong-il Kang
Power Electronics System Laboratory, POESLA
Kookmin University
Seoul, 136-702, Republic of Korea
E-mail : †djhan@kookmin.ac.kr
Visual Display, R&D Team
Samsung Electronics. Co. Ltd.
Suwon, Republic of Korea
E-mail : jeongil.kang@samsung.com
Abstract— In this paper, a high efficiency and high power factor single-stage balanced forward-flyback converter merging a foward and flyback converter topologies is proposed. The conventional AC/DC flyback converter can achieve a good power factor but it has a high offset current through the transformer magnetizing inductor, which results in a large core loss and low power conversion efficiency. And, the conventional forward converter can achieve the good power conversion efficiency with the aid of the low core loss but the input current dead zone near zero cross AC input voltage deteriorates the power factor. On the other hand, since the proposed converter can operate as the forward and flyback converters during switch on and off periods, respectively, it cannot only perform the power transfer during an entire switching period but also achieve the high power factor due to the flyback operation. Moreover, since the current balanced capacitor can minimize the offset current through the transformer magnetizing inductor regardless of the AC input voltage, the core loss and volume of the transformer can be minimized. Therefore, the proposed converter features a high efficiency and high power factor. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a prototype of 24W LED driver are presented.
between AC input and DC output. Even though the two-stage configuration can provide the high power factor, good output regulation and excellent ripple voltage, it has several significant disadvantages such as a large system size, high cost
of
References: products,” in Proceeding of CAID&CD, pp. 1330-1334, Nov. 2009. Electronics, Vol. 57, No. 2, pp. 735, Feb. 2010. Electromics Annual conference, pp. 167-169, 2009. Apr. 2011. in Proceeding of PESC, vol.2, pp. 754-759, 2001. Proceeding of the IEEE, Vol. 1, pp. 357-362, June. 2001. the ECCE2011, pp. 116-121, Sept. 2011.