Gökhan ÇABUK, Selçuk KILINÇ

Reducing electromagnetic interferences in flyback AC-DC converters based on the frequency modulation technique

One of the most preferable types of switched-mode power supplies (SMPS) is the flyback converter, due to its wide range of application areas. Properties such as low cost, provision of multiple output voltage terminals, and higher efficiencies make it important, and hence its usage in technologies including cell phone chargers, personal computers, set-top boxes, and televisions is increasing. Special attention should be paid to the design of this type of converter due to its working principles and electromagnetic interference (EMI) performance. Rapid switching of high current and high voltage during the operation of SMPS causes an EMI problem. The level of the EMI noise should be reduced in order to not interfere with the operation of other equipment. One of the methods for mitigating EMI emissions is the frequency modulation (FM) technique. In this paper, the FM technique, which has been increasingly used as an EMI-reduction method in SMPS, is investigated. The modulation technique that was applied to the switching frequency of the flyback converter is analyzed and its effect on the EMI performance is discussed. The FM technique was tested on an AC-DC flyback converter prototype that was built with an L6566B integrated circuit. Conducted emission noises from the SMPS were measured using an EMI receiver. Experimental results showed that EMI levels were reduced after the application of the FM method.

Anahtar Kelimeler:

Electromagnetic interference, switched-mode power supplies, AC-DC flyback converter, frequency modulation technique

Reducing electromagnetic interferences in flyback AC-DC converters based on the frequency modulation technique

Keywords:

Electromagnetic interference, switched-mode power supplies, AC-DC flyback converter, frequency modulation technique,

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M.H. Nagrial, A. Hellany, “Radiated and conducted EMI emissions in switch mode power supplies (SMPS): sources, causes and predictions”, IEEE Multi Topic Conference, pp. 54-61, 2001.
J. Kaewchai, W. Khangern, S. Nitta, “Controlling conducted EMI emission on a buck-boost converter using gate controlled circuit”, International Symposium on Electromagnetic Compatibility, pp. 541-544, 2002.
G. Antonini, S. Cristina, A. Orlandi, “EMC characterization of SMPS devices: circuit and radiated emissions model”, IEEE Transactions on Electromagnetic Compatibility, Vol. 38, pp. 300-309, 1996.
J. Balcells, D. Gonzalez, J. Gago, A. Santolaria, J.C. Le Bunetel, D. Magnon, S. Brehaut, “Frequency modulation techniques for EMI reduction in SMPS”, European Conference on Power Electronics and Applications, pp. 1-8, L.H. Mweene, “How to ease EMI compliance in power converters”, EE Times Design, pp. 1-2, 2006.
Z.Y. He, F.Y. Shih, Y.T. Chen, Y.P. Wu, “Analysis and design of EMI Şlter for multi-output switching mode power supply”, International Telecommunications Energy Conference, pp. 457-463, 1994.
J. Paramesh, A. Von Jouanne, “Use of sigma-delta modulation to control EMI from switch-mode power supplies”, IEEE Transactions on Industrial Electronics, Vol. 48, pp. 111-117, 2001.
Y.C. Son, S.K. Sul, “Generalization of active Şlters for EMI reduction and harmonics compensation”, Industry Applications Conference, Vol. 2, pp. 1209-1214, 2003.
R. Bera, J. Bera, A.K. Sen, P.R. Dasgupta, “Reduction of EMI from SMPS (switched mode power supplies) by resonance technique and its utilities in industrial process control instruments”, International Conference on Electromagnetic Interference and Compatibility, pp. 445-448, 1999.
K. Yoshida, T. Ishii, N. Nagagata, “Zero voltage switching approach for ﬂyback converter”, International Telecom- munications Energy Conference, pp. 324-329, 1992.
F. Lin, D.Y. Chen, “Reduction of power supply EMI emission by switching frequency modulation”, IEEE Transac- tions on Power Electronics, Vol. 9, pp. 132-137, 1994.
K.K. Tse, H.S.H. Chung, S.Y.R. Hui, H.C. So, “A comparative study of carrier-frequency modulation techniques for conducted EMI suppression in PWM converters”, IEEE Transactions on Industrial Electronics, Vol. 49, pp. 627, 2002.
D. Gonzalez, J. Balcells, A. Santolaria, J.C. Le Bunetel, J. Gago, D. Magnon, S. Brehaut, “Conducted EMI reduction in power converters by means of periodic switching frequency modulation”, IEEE Transactions on Power Electronics, Vol. 22, pp. 2271-2281, 2007.
G. C¸ abuk, S. Kılın¸c, “C¸ apraz (ﬂyback) ¸ceviricilerde frekans mod¨ulasyonu tekni˘gi kullanılarak elektromanyetik giri¸simlerin azaltılması” (in Turkish), Electrical, Electronics, Computer and Biomedical Engineering National Congress, pp. 207-212, 2009.
L6566B Multi-Mode Controller for SMPS, Data Sheet, ST Microelectronics, 2008.
S. Haykin, Communication Systems, New York, John Wiley & Sons, 1994.
J.R. Carson, “Notes on the theory of modulation”, Proc. IRE, Vol. 10, pp. 57-54, 1922.
Y.S. Lee, Computer-Aided Analysis and Design of Switch-Mode Power Supplies, New York, Marcel-Dekker, 1993.