Title: Direct vector controlled six-phase asymmetrical induction motor with power balanced space vector PWM multilevel operation

Authors: Padmanaban Sanjeevikumar; Gabriele Grandi; Joseph Olorunfemi Ojo; Frede Blaabjerg

Addresses: Ohm Technologies, Research and Development, Chennai, Tamil Nadu, 600122, India ' Department of Electrical, Electronic and Information Engineering, University of Bologna, Alma Mater Studiorum 1088AD, Bologna, 40136, Italy ' Center for Energy Systems Research, Department of Electrical and Computer Engineering, Tennessee Technological University, Cookeville, 38505, TN, USA; Eskom Centre of Excellence in HVDC Engineering, University of KwaZulu-Natal, Durban, South Africa ' Department of Energy Technology, Aalborg University, Pontoppidanstraede 101, Aalborg, 9220, Denmark

Abstract: In this paper, a six-phase (asymmetrical) machine is investigated, 300 phase displacement is set between two three-phase stator windings keeping deliberately in open-end configuration. Power supply consists of four classical three-phase voltage inverters (VSIs), each one connected to the open-winding terminals. An original synchronous field oriented control (FOC) algorithm with three variables as degree of freedom is proposed, allowing power sharing among the four VSIs in symmetric/asymmetric conditions. A standard three-level space vector pulse width modulation (SVPWM) by nearest three vector (NTV) approach was adopted for each couple of VSIs to operate as multilevel output voltage generators. The proposed power sharing algorithm is verified for the ac drive system by observing the dynamic behaviours in different set conditions by complete simulation modelling in software (Matlab/Simulink-PLECS) and the results are provided in this paper. Furthermore, harmonic components are shown in each subspace and analysed with Fourier spectrum to confirm the smooth torque propagation with free of harmonic components. The numerical simulation results provided in this paper are closely matching with theoretical developments.

Keywords: open-end winding machines; multiphase machines; power sharing algorithm; field oriented control; FOC; multiphase space vectors; multiphase inverters; classical voltage source inverters; asymmetrical induction motors; pulse width modulation; space vector PWM; AC drive systems; numerical simulation; modelling; torque propagation.

DOI: 10.1504/IJPEC.2016.075068

International Journal of Power and Energy Conversion, 2016 Vol.7 No.1, pp.57 - 83

Received: 31 Oct 2014
Accepted: 01 Apr 2015
Published online: 02 Mar 2016 *

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