A Multilevel Converter with a Floating Bridge for Open-End Winding Motor Drive Applications

Shajjad Chowdhury, Patrick W. Wheeler, Chintan Patel, Chris Gerada

Research output: Journal PublicationArticlepeer-review

81 Citations (Scopus)


This paper presents a three-phase open-end winding induction motor drive. The drive consists of a three-phase induction machine with open stator phase windings and dual-bridge inverter supplied from a single dc voltage source. To achieve multilevel output voltage waveforms, a floating capacitor bank is used for the second of the dual bridges. The capacitor voltage is regulated using redundant switching states at half of the main dc-link voltage. This particular voltage ratio (2:1) is used to create a multilevel output voltage waveform with three levels. A modified modulation scheme is used to improve the waveform quality of this dual inverter. This paper also compares the losses in the dual-inverter system in contrast with a single-sided three-level neutral point clamped converter. Finally, detailed simulation and experimental results are presented for the motor drive operating as an open-loop v /f controlled motor drive and as a closed-loop field-oriented motor controller.

Original languageEnglish
Article number7463475
Pages (from-to)5366-5375
Number of pages10
JournalIEEE Transactions on Industrial Electronics
Issue number9
Publication statusPublished - Sept 2016


  • Field-oriented control (FOC)
  • floating bridge
  • open-end winding induction machine
  • space vector

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


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