Research on relationship between harmonic currents and resultant harmonic magnetomotive forces in multiphase machines

Wang, Dong; Zheng, Xiaoqin; Cheng, Siwei

doi:10.1109/itec-ap.2014.6941283

Cited by 4 publications

(2 citation statements)

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“…Bianchi doesn't consider higher time-harmonic content. As recent as 2014 and 2015, Wei [31], Wang [32] and Zhang [33] have presented interesting insights on the harmonic content of electric machines. Wei does consider a preliminary study of the time-and spatial-harmonic content.…”

Section: A Literaturementioning

confidence: 99%

Time- and Spatial-Harmonic Content in Synchronous Electrical Machines

2016

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The use of power electronics has led to a growing importance of higher time-harmonic content in electrical machines. To gain insight in phenomena related to these higher harmonics, such as noise and losses, a good understanding of the magnetic field's harmonic content is mandatory. Moreover, the development of fast and accurate, harmonic-based, analytical models requires a qualitative knowledge of the machine's time-and spatial-harmonic content. Although the harmonic content of electric machines is an extensively studied topic, previous publications tended to focus on one type of synchronous machines and often didn't consider higher time-harmonic orders. This work complements the existing theory by providing a more general approach, thereby covering machines and operating points that weren't covered until now. It considers both three-phase and multi-phase machines with an odd number of phases. The winding distribution can either have an integer or a fractional number of slots per pole and per phase and higher time-harmonic content is regarded as well. Note that saturation is neglected. Despite its general validity, the work succeeds at providing one simple equation to determine the machine's time-and spatial-harmonic content. Moreover, the work also extensively discusses the physical causes of the harmonic content. The combination of this general validity, the simple result and the insight in the physics makes that this work is a strong tool to both study harmonic-related phenomena in electric machines and to develop harmonic-based analytical models.

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Section: A Literaturementioning

confidence: 99%

Time- and Spatial-Harmonic Content in Synchronous Electrical Machines

2016

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“…Extensive research has been carried out on modelling and finding appropriate decoupling matrices for split-phase machines with both multiple and single neutral points [13][14][15][16][17]. Analysis of the torque ripple harmonics has been also carried out [12,18]. Nevertheless, the properties of low order harmonics in this particular type of multiphase machines have not been explored in the past and this is the subject this paper deals with.…”

Section: Introductionmentioning

confidence: 99%

Phase voltage harmonic imbalance in asymmetrical multiphase machines with single neutral point

Zoric

Jones

Levi

2016

IECON 2016 - 42nd Annual Conference of the IEEE Industrial Electronics Society

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Abstract-Multiphase (n-phase) machines are often designed with l sub-windings on stator, each having k phases, and the machine is typically operated with l isolated neutral points. However, such a machine can also operate with a single neutral point, which improves the fault-tolerant properties. When a machine is inverter supplied, low order harmonics may be present due to the low switching frequency and nonlinear inverter properties. Moreover, low order zero-sequence harmonics can be deliberately injected to increase dc bus voltage utilisation. This paper investigates a phenomenon that has not been reported so far in relation to asymmetrical multiphase machines with a single neutral point, namely that the presence of balanced low order harmonics in leg voltages produces unbalanced phase voltage harmonics and consequently unbalanced phase current harmonics. By analysing the neutral point (common mode) voltage harmonics, imbalance in the phase voltage harmonics is explained. Analytical expressions for neutral point voltage harmonics and phase voltage harmonics are provided for asymmetrical machine configurations with a single neutral point having arbitrary numbers of sub-windings and subwinding phases. Theoretical considerations are verified using simulations and experiments with asymmetrical twelve-and ninephase loads with a single neutral point, respectively.

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