Negative Imaginary Stability Result Allowing Purely Imaginary Poles in Both the Interconnected Systems

Parijat Bhowmick, Arnab Dey

Research output: Contribution to journalArticlepeer-review

Abstract

This paper extends the class of systems to which negative imaginary (NI) stability result can be (directly) applied. The existing closed-loop stability results for NI interconnections require at least one of the systems to satisfy strictly negative imaginary (SNI) properties and hence do not allow purely imaginary poles in both the systems. In contrast to this, a set of necessary and sufficient conditions is derived in this brief for the internal stability of two NI systems in a positive feedback loop with possible poles on the imaginary axis excluding the origin. This proposed result also captures all the existing closed-loop stability results of NI systems, without poles at the origin, as special cases. Illustrative numerical examples are studied to show the usefulness of this development.

Original languageEnglish
Pages (from-to)403-408
JournalIEEE Control Systems Letters
Volume6
DOIs
Publication statusPublished - 5 May 2021

Keywords

  • Asymptotic stability
  • DC loop gain
  • Feedback loop
  • Filtering theory
  • Frequency response
  • internal stability.
  • Negative imaginary system
  • Numerical stability
  • Poles and zeros
  • positive feedback
  • Stability criteria

Fingerprint

Dive into the research topics of 'Negative Imaginary Stability Result Allowing Purely Imaginary Poles in Both the Interconnected Systems'. Together they form a unique fingerprint.

Cite this