Abstract—A rigorous mathematical analysis and a comparative study of carrier-frequency modulation (CFM) techniques for the conducted electromagnetic interference (EMI) suppression in pulsewidth-modulated converters is presented. CFM techniques dither the

622IEEETRANSACTIONSONINDUSTRIALELECTRONICS,VOL.49,NO.3,JUNE

2002

(a)

(b)

(c)

Fig.5.Theoreticalpowerspectraoftheinputcurrentwithf =16.

=6kHzand =2.(b)1f

=48kHzand

modelthefilterattenuation.Thefilterresponse

functionByusingthepropertyin(9b),thetotalpowerof

the

(19)

mated

by

where

dB,

anddB.

Hence,themeasuredpower

at

thatfalls

withincanbeapproxi-

issmall.Thiscanbeachievedbyeither

reducing

or

increasing

willbesmallandthe

magnitudeofthesidefrequencieswillincrease.

If(20)

where

.