Four-Degree-of-Freedom Overmodulation Strategy for Five-Phase Space Vector Pulsewidth Modulation

Feifei Bu, Tianyu Pu, Qi Liu, Beijia Ma, Michele Degano, Chris Gerada

Research output: Journal PublicationArticlepeer-review

13 Citations (Scopus)


This article proposes a four-degree-of-freedom overmodulation strategy for five-phase space vector pulsewidth modulation (SVPWM) in order to reduce the low-order harmonics of the output voltage during overmodulation. Based on the nearest-four-vector SVPWM algorithm, this overmodulation strategy calculates the corresponding third harmonic injection rate according to the modulation ratio in the overmodulation region. What is more, this strategy optimizes and controls the third harmonic so that basic voltage vectors of the fundamental wave subspace and the third harmonic subspace can be controlled simultaneously, thus effectively decreasing the low-order harmonic contents without reducing control degrees of freedom. The whole overmodulation region is divided into three subregions with linearized approximation to reduce the complexity of computation. Simulation and experimental results demonstrate that under the same modulation ratio during overmodulation, the proposed overmodulation strategy can improve the dc bus voltage utilization of a five-phase inverter, make the third harmonic controllable with four control degrees of freedom, and also reduce the low-order harmonic contents of the output voltage.

Original languageEnglish
Article number9087885
Pages (from-to)1578-1590
Number of pages13
JournalIEEE Journal of Emerging and Selected Topics in Power Electronics
Issue number2
Publication statusPublished - Apr 2021


  • Degrees of freedom
  • multiphase inverter
  • overmodulation strategy
  • space vector pulsewidth modulation (SVPWM)
  • third harmonic

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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