Reduction of Low Space Harmonics for the Fractional Slot Concentrated Windings Using a Novel Stator Design

Dajaku, Gurakuq; Xie, Wei; Gerling, Dieter

doi:10.1109/tmag.2013.2294754

Cited by 159 publications

(72 citation statements)

References 26 publications

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“…This would increase the reluctance in the yoke and act as a flux barrier, reducing the subharmonic fluxes in both the stator and rotor yokes. This is a known method of reducing the induced losses in the rotors of fractional-slot winding machines [16], [17]. Additional flux barriers could also be placed in the locations where the flux is highest.…”

Section: Discussionmentioning

confidence: 99%

Analytical Calculation of Yoke Flux Patterns in Fractional-Slot Permanent Magnet Machines

Røkke

Nilssen

2017

IEEE Trans. Magn.

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Machine design problems are often solved under the assumption of no-load when calculating iron flux densities. However, it is particularly important to account for the fluxes from the stator currents, the armature reaction, in fractional-slot machines. The fluxes from the permanent magnets and the armature reaction both vary in time with the electrical frequency. By studying the flux that flows along the stator yoke behind every slot in such a machine, it is revealed that the armature reaction flux does not have the same amplitude behind all slots. In addition, it is revealed that the time-varying no-load and armature reaction fluxes are shifted in time, with different phase shifts behind different slots. The sum of the no-load and armature reaction fluxes, namely, the load flux, depends on both the amplitudes of the fluxes and the phase shift between them. The resulting load flux behind each slot varies significantly. In four investigated machines, the ratio of the highest to the lowest load flux amplitude ranges between 1.6 and 6. The load flux can be significantly higher than the no-load flux. The flux calculations are verified through finite-element analysis in all four machines, and the error in the maximum load flux ranges between 2% and 6%.

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Section: Discussionmentioning

confidence: 99%

Analytical Calculation of Yoke Flux Patterns in Fractional-Slot Permanent Magnet Machines

Røkke

Nilssen

2017

IEEE Trans. Magn.

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“…The implication being, an improved overall machine efficiency. Similarly, as demonstrated in [5], by introducing flux barriers in the stator yoke design of PM machines having non-overlapping concentrated windings, large percentage of its MMF sub-harmonics are minimized or more even eliminated completely. Consequently, it will lead to significant reduction of core and PM eddy current losses; and thus, enhance the machine's efficiency.…”

Section: Introductionmentioning

confidence: 94%

The impact of machine geometries on the average torque of dual-stator permanent magnet machines

Awah

Okoro

2018

Nig. J. Tech.

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The influence of leading design parameters such as rotor radial size and arc lengths, aspect ratio, stator yoke thickness, stator tooth-width and slot-opening/slot pitch-ratio etc. on the average torque of permanent magnet (PM) machines having dual-stator arrangement is investigated in this study. Further, the effect of their different rotor pole numbers is also presented and quantitatively compared. The analyzed machines are optimized using the evolutionary approach with a goal for optimum torque yield. The analysis shows that, each of the varied machine parameters has an optimum value for maximum torque production owing to their varying electromagnetic reaction which tends to saturate at some point on the magnetic path. Moreover, the best performance amongst the investigated machines is given by the machine type having eleven rotor pole number.Keywords: average torque, dual start, machine geometry, optimal value, PM machines 1. INTRODUCTION The influence of machine design parameters on the overall performance of electric machines cannot be over-emphasized. This is because the output torque, power and hence efficiency of the machine ultimately depends on its optimal geometries. Thus, we have devoted this work to the impact of these design parameters which includes: the split-ratio, slot opening, stator back-iron thickness, stator tooth-width, and rotor radial size, etc. on the average torque of double-stator PM machines. An improved efficiency and torque-density design of dual rotor PM machine is proposed in [1]; it is noted that, machines having toroidal windings could deliver higher output torque and better efficiency than their counterparts equipped with traditional winding topologies. Similarly, a doublestator PM machine capable of producing large torque is realized in [2], by adopting the optimal split-ratio of the machine. Further, other design parameters such as permanent magnet length, back-iron size etc. were obtained by optimal sizing equations and also seen to contribute to the performance of the machine. In order to predict the electromagnetic performance of synchronous PM machines, fast analytical optimization techniques with high accuracy compared to finite element analysis is adopted in [3]. The investigation in [3] also revealed that, design parameters such as the

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“…Here, only a double layer winding is considered, aiming for the best possible design in terms of MMF and its harmonics within this class of windings. Another approach to improve the performance of IMs machines with fractional-slot windings has been presented in [4] and [5]. In [4], additional teeth without windings are added to the design and the coils are wound with different numbers of turns per coil.…”

Section: Overview Of Investigated Machine Designsmentioning

confidence: 99%

Comparison of an induction machine with both conventionally distributed and fractional-slot concentrated stator windings

Bacher

Mütze

2015

Elektrotech. Inftech.

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The desired high energy conversion efficiencies over a complete operating torque and speed range combined with the recent increase in cost of rare-earth magnets have brought forth a renewed interest in the induction machine (IM) as a possible alternative to the rareearth permanent magnet (PM) machine. Fractional-slot concentrated windings (FSCWs) allow significant cost reduction of a machine by reducing copper volume and manufacturing time. However, this type of winding is generally discussed in the context of brushless PM machines. The higher harmonic content of FSCWs is generally understood to be a significant drawback for such designs. We aim to substantiate this understanding by comparing the performances of a baseline IM with a conventional, distributed winding to machines with FSCWs. Betrachtung einer Drehstromasynchronmaschine mit Zahnspulentechnik. Der hohe und auch stark schwankende Magnetpreis von Seltenerdmagneten führt vermehrt zum Wunsch, Rotoren von Permanentmagnet-erregten Motoren mit Zahnspulenwicklungen im Ständer durch solche von Asynchronmaschinen zu ersetzen (Käfigläufer). Diese Kombination soll bei nahezu gleich guter Leistungsdichte, aufgrund des reduzierten Kupfervolumens und kürzerer Fertigungszeit, die Herstellungskosten wesentlich senken. Im Vergleich mit verteilten Wicklungen weisen Zahnspulenwicklungen einen erhöhtenAnteil an Oberwellen auf, was allgemein als Nachteil für eine mögliche Realisierung von Asynchronmaschinen mit einer derartigen Ständerwicklung gesehen wird. Mit dieser Veröffentlichung soll dieses Verständnis durch einen systematischen Vergleich zweier Asynchronmaschinen, einer mit einer verteilten Ständerwicklung und einer mit einer Ständerwicklung in Zahnspulentechnik, aufgearbeitet und anschaulich herausgearbeitet werden.

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Reduction of Low Space Harmonics for the Fractional Slot Concentrated Windings Using a Novel Stator Design

Cited by 159 publications

References 26 publications

Analytical Calculation of Yoke Flux Patterns in Fractional-Slot Permanent Magnet Machines

Analytical Calculation of Yoke Flux Patterns in Fractional-Slot Permanent Magnet Machines

The impact of machine geometries on the average torque of dual-stator permanent magnet machines

Comparison of an induction machine with both conventionally distributed and fractional-slot concentrated stator windings

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