A Voltage Space Vector Diagram Formed by Nineteen Concentric Dodecagons for Medium-Voltage Induction Motor Drive

R. Sudharshan Kaarthik, K. Gopakumar, Carlo Cecati, Istvan Nagy

Research output: Contribution to journalArticle

17 Citations (Scopus)


In this paper, a multilevel dodecagonal voltage space vector structure with nineteen concentric dodecagons is proposed for the first time. This space vector structure is achieved by cascading two sets of asymmetric three-level inverters with isolated H-bridges on either side of an open-end winding induction motor. The dodecagonal structure is made possible by proper selection of dc link voltages and switching states of the inverters. The proposed scheme retains all the advantages of multilevel topologies as well as the advantages of dodecagonal voltage space vector structure. In addition to that, a generic and simple method for calculation of pulsewidth modulation timings using only sampled reference values ( vα and vβ) is proposed. This enables the scheme to be used for any closed-loop application such as vector control. In addition, a new method of switching technique is proposed, which ensures minimum switching while eliminating the fifth-and seventh-order harmonics and suppressing the eleventh and thirteenth harmonics, eliminating the need for bulky filters. The motor phase voltage is a 24-stepped waveform for the entire modulation range thereby reducing the number of switchings of the individual inverter modules. Experimental results for steady-state operation, transient operation, including start-up have been presented and the results of fast Fourier transform analysis is also presented for validating the proposed concept.

Original languageEnglish
Article number7112131
Pages (from-to)6748-6755
Number of pages8
JournalIEEE Transactions on Industrial Electronics
Issue number11
Publication statusPublished - Nov 1 2015



  • Cascaded H-bridge
  • Dodecagonal Voltage Space Vector Structure
  • Induction Motor Drive
  • Multilevel Inverters
  • Neutral Point Clamped Inverter
  • Pulse Width Modulation

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering

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