Conducted emi mitigation in switched mode dc-dc converters by spread spectrum techniques

In this paper effectiveness of spread spectrum modulation techniques to the electromagnetic interference (EMI) suppression is investigated. Comparative evaluation of spread spectrum methods is reviewed and demonstrated with the aid of function generator and EMI receiver. Obtained results indicate advantageous features of random carrier fre- quency modulation (CFM), which results in more steady spectral distribution. For a switch mode dc-dc converter, random CFM is systematically tested. This study has indicated the adequacy of quasi-peak detector of EMI receiver to char- acterize the spread spectrum techniques. Based on input con- verter current measurements using EMI receiver, conducted emission spectra are evaluated in function of the defined randomness index R and frequency range. For the acceptable range of R variations up the 20dB EMI suppression level was reached.

[1]  K. J. Tseng,et al.  EMI suppression with switching frequency modulated DC-DC converters , 1999 .

[2]  Hing Cheung So,et al.  Analysis and spectral characteristics of a spread-spectrum technique for conducted EMI suppression , 2000 .

[3]  F. Lin,et al.  Reduction of power supply EMI emission by switching frequency modulation , 1993, Proceedings of IEEE Power Electronics Specialist Conference - PESC '93.

[4]  Frede Blaabjerg,et al.  Random modulation techniques with fixed switching frequency for three-phase power converters , 1999, 30th Annual IEEE Power Electronics Specialists Conference. Record. (Cat. No.99CH36321).

[5]  Henry Shu-Hung Chung,et al.  A comparative investigation on the use of random modulation schemes for DC/DC converters , 2000, IEEE Trans. Ind. Electron..

[6]  Henry Shu-Hung Chung,et al.  A comparative study of carrier-frequency modulation techniques for conducted EMI suppression in PWM converters , 2002, IEEE Trans. Ind. Electron..

[7]  Robert C. Dixon,et al.  Spread‐spectrum systems , 1976 .

[8]  Robert C. Dixon,et al.  Spread spectrum techniques , 1976 .

[9]  Thomas G. Habetler,et al.  Angle controlled current regulated rectifiers for AC/AC converters , 1989 .

[10]  T. Habetler,et al.  Acoustic noise reduction in sinusoidal PWM drives using a randomly modulated carrier , 1989, 20th Annual IEEE Power Electronics Specialists Conference.

[11]  S. K. Das,et al.  Importance of receiver dwell time in emission measurements , 1999, Proceedings of the International Conference on Electromagnetic Interference and Compatibility.

[12]  D. Hansen,et al.  Modulation impact on quasi-peak detector response , 1997, IEEE 1997, EMC, Austin Style. IEEE 1997 International Symposium on Electromagnetic Compatibility. Symposium Record (Cat. No.97CH36113).