Influence of bi-directional power flow on impedance and stability of cascaded systems

Yinglai Xia, Raja Ayyanar

Research output: Chapter in Book/Report/Conference proceedingConference contribution

10 Scopus citations


This paper presents an impedance based stability criterion of cascaded active converter systems with bi-directional power flow from the perspective of individual subsystems. Influence of bi-directional power flow on the impedance of the subsystems and the stability of the cascaded system are studied. Though bi-directional power flow does not change the stability criterion, it changes the impedance (mostly the phase) of the susbsystems. Unstable critical frequencies caused by impedance interaction are predicted by the proposed impedance criterion in bi-directional power flow situation. Simulation results of a cascaded system comprising of a dual active bridge (DAB) dc-dc stage and a H bridge dc-ac stage are presented as an example to verify the analysis of the influence of bi-directional power flow. The small signal impedance on the dc side of the single phase H bridge is calculated based on power balance analysis. Controller improvement approaches to eliminate impedance interaction between subsystems are discussed.

Original languageEnglish (US)
Title of host publicationIECON Proceedings (Industrial Electronics Conference)
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages7
ISBN (Electronic)9781479940325
StatePublished - Feb 24 2014

Publication series

NameIECON Proceedings (Industrial Electronics Conference)


  • Bi-directional power flow
  • Controller improvement
  • Impedance interaction
  • Stability criterion

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


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