A novel filter structure to suppress circulating currents based on the sequence of sideband harmonics for high-power interleaved motor-drive systems

Sungjae Ohn, Hyun Sam Jung, Dushan Boroyevich, Seung Ki Sul

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

In this paper, a novel filter structure to suppress circulating currents is proposed based on the sequence of pulsewidth modulation voltage harmonics for high-power interleaved motor-drive systems. The sideband harmonics can be divided into positive-, negative-, and zero-sequence components. Through 120° interleaving among three paralleled inverters, a majority of positive- and negative-sequence harmonics are phase shifted. By these phase shifts, the differential-mode circulating currents between the paralleled ac-dc converters can be suppressed with the proposed filters, which have an identical structure to the three-phase common-mode chokes. Such a structure highly benefits the design and manufacturability for high-power applications where a choice of magnetic-core shapes is limited. Compared to coupled inductors (CIs) with cyclic-cascade or monolithic configurations, the number of magnetic cores can be reduced by one-third. Peak flux-linkages of the proposed filters and the conventional CIs were compared to estimate the size reduction in case of flux-limited designs. Considering the whole modulation index range, which may be required in the motor-drive systems, the maximum flux-linkage can be reduced by 50%. Prototype filters are built and showed a 33% reduction in weight and size compared to the conventional CIs. The validity of the proposed filter is verified through the simulation and a small-scale experiment.

Original languageEnglish
Article number8698855
Pages (from-to)853-866
Number of pages14
JournalIEEE Transactions on Power Electronics
Volume35
Issue number1
DOIs
StatePublished - Jan 2020

Keywords

  • Circulating currents
  • coupled inductors (CIs)
  • interphase inductors
  • magnetic integration
  • parallel three-phase inverters
  • pulsewidth modulation (PWM)

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