Improved flux pattern with third harmonic injection for multiphase induction machines

Ayman S. Abdel-Khalik*, Mahmoud I. Masoud, Barry W. Williams

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

114 Citations (Scopus)


This paper presents an indirect vector control scheme with an improved flux pattern using third harmonic injection. The control objective is to independently control both flux and torque and to generate a nearly rectangular air-gap flux, resulting in improved machine power density. If there is a proportional relation between the third harmonic and fundamental plane currents, variable misalignment between fundamental and third air-gap flux components occurs with varying mechanical loading. Due to this misalignment, saturation may take place. Accordingly, the total flux is saturated and iron loss increases. Hence, coupling results between different sequence planes. Instead of a proportional relation between the current components, direct and quadrature current components of the injected third harmonic current reference are a function of the fundamental direct and quadrature reference current components, respectively. These functions ensure that the air-gap flux is near rectangular with a maximum value of 1 p.u. from no load to full load. Moreover, this controller guarantees complete decoupling between the sequence planes. An eleven-phase induction machine is used to validate the proposed controller experimentally, while supporting simulation results and theoretical analysis use both MATLAB and finite element platforms.

Original languageEnglish
Article number5967917
Pages (from-to)1563-1578
Number of pages16
JournalIEEE Transactions on Power Electronics
Issue number3
Publication statusPublished - 2012


  • Dual-plane
  • eleven-phase
  • indirect vector control
  • multiphase induction machine
  • rectangular air-gap flux
  • third harmonic injection

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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