Analysis and spectral characteristics of a spread-spectrum technique for conducted EMI suppression

Author

Tse, K.K. ; Chung, Henry Shu Hung ; Huo, S.Y. ; So, H.C.

Author_Institution

Dept. of Electron. Eng., City Univ. of Hong Kong, Hong Kong

Volume

15

Issue

2

fYear

2000

fDate

3/1/2000 12:00:00 AM

Firstpage

399

Lastpage

410

Abstract

Frequency modulation (FM) and random switching methods have been used for reducing conducted electromagnetic interference (EMI) in power converters. Limited theoretical studies and comparisons of these schemes, however, are available. In this paper, a detailed analysis and the spectral characteristics of a random carrier-frequency (RCF) technique for suppressing conducted EMI in an offline switched-mode power supply are presented. The analysis provides a theoretical platform for studying the characteristics of this random switching scheme. The level of randomness is defined for the RCF scheme and varied in the converter example so that the effects on the power spectra can be demonstrated. Theoretical predictions of the spectral characteristics of this scheme are confirmed with measurements. The RCF scheme has been compared with the standard constant-frequency pulsewidth modulation (PWM) scheme and the FM scheme. Comparisons of their spectral performance show that the RCF scheme has better conducted EMI suppression than the FM and standard PWM schemes

Keywords

AC-DC power convertors; electromagnetic interference; frequency modulation; interference suppression; pulse width modulation; random processes; spectral analysis; switching circuits; AC-DC power conversion; FM scheme; conducted EMI suppression; conducted electromagnetic interference reduction; constant-frequency pulsewidth modulation; frequency modulation; offline switched-mode power supply; power converters; random carrier-frequency technique; random switching methods; random switching scheme; spectral characteristics; spread-spectrum technique; Capacitors; Electromagnetic compatibility; Electromagnetic interference; Power harmonic filters; Power system harmonics; Pulse width modulation; Pulse width modulation converters; Spectral analysis; Spread spectrum communication; Switched-mode power supply;

fLanguage

English

Journal_Title

Power Electronics, IEEE Transactions on

Publisher

ieee

ISSN

0885-8993

Type

jour

DOI

10.1109/63.838113

Filename

838113