Low-frequency hopf bifurcation and its effects on stability margin in three-phase PFC power supplies connected to non-ideal power grid

Meng Huang, Chi Kong Tse, Siu Chung Wong, Cheng Wan, Xinbo Ruan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

51 Citations (Scopus)


Three-phase power-factor-correction (PFC) power supplies are commonly used to convert ac power from a three-phase grid to a regulated dc voltage with unity input power factor. The output voltage regulation is normally achieved by an outer voltage feedback loop and a sinusoidal pulse-width-modulated (SPWM) inner current loop. However, the non-ideal power grid may drive the converter to enter a low-frequency instability region. In this paper, a low-frequency instability phenomenon in three-phase PFC power supplies is reported. The converter can also be regarded as exhibiting a Hopf-type bifurcation in which the dc output voltage oscillates at 150 Hz, and a large amount of harmonics appear on the line current. We develop an averaged model of the grid-converter system to predict the low-frequency instability. The effects of circuit and grid parameters can be studied with this model. Additionally, as a result of the emergence of low-frequency oscillation, the stability boundary leading to a catastrophic bifurcation changes dramatically. Simulation results also provide design-oriented boundaries of operation. This phenomenon is confirmed by experimental measurement.
Original languageEnglish
Article number6605630
Pages (from-to)3328-3340
Number of pages13
JournalIEEE Transactions on Circuits and Systems I: Regular Papers
Issue number12
Publication statusPublished - 1 Dec 2013


  • Catastrophic bifurcation
  • grid interaction
  • Hopf bifurcation
  • low-frequency instability
  • three-phase voltage source converter

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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