Small-Signal Models with Extended Frequency Range for DC-DC Converters with Large Modulation Ripple Amplitude

Xin Li, Xinbo Ruan, Qian Jin, Mengke Sha, Chi K. Tse

Research output: Journal article publicationJournal articleAcademic researchpeer-review

35 Citations (Scopus)


Application of pulse width modulation (PWM) is known to produce sideband effects. The accuracy of the models of dc-dc converters can be improved if essential information of the sideband effects of PWM can be incorporated. In this paper, the aliasing effect of the sideband components on the closed-loop control is analyzed, and an effective representation of the transfer function of the pulse-width modulator is derived. Applying this transfer function to the dc-dc converter, an extended-frequency-range small-signal model is obtained, which can be conveniently used for deriving the loop gain of a PWM-controlled dc-dc converter. Furthermore, for wideband control applications, the large switching ripple in the modulation signal necessitates adjustment of the representation of the gain of the pulse-width modulator, which is dependent on the controller. Despite being highly accurate for stability assessment, the extended-frequency-range model is relatively complex after incorporating the effects of the sideband components and the large switching ripple. An approximate approach is introduced to simplify the loop gain expression and to provide physical insights into the effects of the sideband components and large modulation ripple amplitude. Experimental verification of the extended-frequency-range model is provided for a buck converter and a boost converter.

Original languageEnglish
Pages (from-to)8151-8163
Number of pages13
JournalIEEE Transactions on Power Electronics
Issue number9
Publication statusPublished - Sept 2018


  • Extended-frequency-range model
  • large modulation signal
  • pulse width modulation (PWM)
  • sideband component

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


Dive into the research topics of 'Small-Signal Models with Extended Frequency Range for DC-DC Converters with Large Modulation Ripple Amplitude'. Together they form a unique fingerprint.

Cite this