Effect of Number of Phases on Electromagnetic Torque of Synchronous Machines

Alaeddini, Ali; Tahanian, Hamed

doi:10.12720/ijoee.2.3.194-199

Cited by 3 publications

(3 citation statements)

References 4 publications

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“…This section discusses briefly the influence of increasing number of phases on the electromagnetic torque ripple of electrical machines. Vibrations and noise associated with electrical machines mainly result from ripples in the electromagnetic torque [32]. These ripples are generated from harmonics of the internal induced voltages and the phase currents of electrical machines.…”

Section: Analysis Of Torque Ripplesmentioning

confidence: 99%

Performance Analysis of a Rewound Multiphase Synchronous Reluctance Machine

Tawfiq

Ibrahim

El-Kholy

et al. 2022

IEEE J. Emerg. Sel. Topics Power Electron.

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This paper analyses the performance of synchronous reluctance motors (SynRMs) when an existing three-phase stator is rewound to a higher number of phases. The introduced rewinding technique offers an optimized distribution for air gap flux, higher winding factor and higher value for the fundamental component of the magneto-motive force with lower harmonics. The number of turns of the proposed multiphase winding is calculated, keeping fixed copper volume. Finite element simulations verified that the torque density of the rewound five and seven-phase SynRMs is enhanced by 6.56% and 3.37% respectively over the existing machine under rated conditions. The torque ripple is also reduced by 17.13% and 15.87% respectively. Further, the efficiency is enhanced with the rewound machines by 0.3% at rated condition. Moreover, the torque gain is greatly increased to 23.48% at higher speed (9000rpm) and the efficiency is also increased by 3 %. The main advantage of the rewound machine is clearly observed in case of an open circuit fault. With onephase opened, the rewound machine can work at 78% of the healthy rated torque, while the three-phase machine works at only 43% with a very huge torque ripple about 228%. Experimental measurements are obtained to validate the theoretical work.

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Section: Analysis Of Torque Ripplesmentioning

confidence: 99%

Performance Analysis of a Rewound Multiphase Synchronous Reluctance Machine

Tawfiq

Ibrahim

El-Kholy

et al. 2022

IEEE J. Emerg. Sel. Topics Power Electron.

View full text Add to dashboard Cite

show abstract

“…Most of the research work focuses on the odd phase number, e.g., five and seven phases [24,25]. This is because even phase numbers contain higher MMF harmonics, and this results in an increased torque ripple and losses [26,27]. Hence, the following analysis will be carried out to investigate the possibility of upgrading an existing three-phase SynRM to construct a five-and/or seven-phase SynRM using the existing rotor.…”

Section: Selection Of Stator Slots and Coil Turnsmentioning

confidence: 99%

Refurbishing three-phase synchronous reluctance machines to multiphase machines

et al. 2020

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Refurbishing electrical machines to have a higher performance and/or reliability is a clear trend in the circular economy. This paper investigates the gain in efficiency, torque density and reliability with replacing the windings and the iron of the stator of existing three-phase synchronous reluctance machines (SynRMs), resulting in a multiphase machine. The stator housing, shaft, bearings and the rotor are not changed, to keep the cost of refurbishing low. As the housing and rotor are kept, logical constraints are to have the same inner and/or outer stator diameters, air gap length and axial length. In the new windings, an identical copper volume is considered as a constraint. An optimization technique is coupled to 2D finite element method to select the optimal slot dimensions. Case studies showed that it is possible to replace the stator of existing three-phase SynRMs with a better performance multiphase one. It is found that the average torque, efficiency and power factor of the five-phase SynRM are increased by 11.78%, 0.72% and 5.54%, respectively, compared to a three-phase SynRM at rated conditions. At higher speeds (three times rated value), the efficiency and average torque are greatly improved by about 3.64% and 33.67%, respectively, compared to the three-phase SynRM. Moreover, a faulty case of one phase opened is also investigated. The five-phase SynRM works at 75.45% of the healthy rated torque of the three-phase SynRM, whereas the three-phase SynRM works at only 43%. Measurements on an existing 5.5-kW, three-phase SynRM confirm the observed results.

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“…Most of the recent research in multiphase machines focuses on the odd phase number, e.g. five and seven phases, because the higher MMF harmonics of the even phase numbers results in increased torque ripple and losses [20,21]. Hence, this section investigates the performance of SynRM by replacing the 3-phase stator iron and winding to a 5-phase winding, keeping the same rotor to minimize the cost.…”

Section: Stator Design and Optimizationmentioning

confidence: 99%

Performance Improvement of Existing Three Phase Synchronous Reluctance Machine: Stator Upgrading to 5-Phase With Combined Star-Pentagon Winding

et al. 2020

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This paper investigates the performance of 3-phase synchronous reluctance machines (SynRMs) when upgrading their stator to 5-phase, keeping the same rotor. The design of the 5-phase stator has been optimized to select the optimal dimensions of the slots and teeth. Moreover, a combined starpentagon winding is employed to further improve the machine performance. Different winding configurations have been studied and compared using 2D Ansys Maxwell transient simulations. It is observed that at optimal current angle and rated current, the average torque is increased by 17.41% when changing the 3-phase stator with the proposed 5-phase one. In addition, the efficiency of the 5-phase SynRM is increased by about 0.8% compared to 3-phase SynRM. At 3 times the rated speed, the torque and efficiency are significantly increased by around 33% and 3.5% respectively. Moreover, the 5-phase SynRM shows a superior performance in the faulty case with one phase opened. It works at 98.84% of the rated torque of the healthy 3-phase machine, whereas the 3-phase machine works at only 43.35% with huge torque ripple (228%). Finally, an experimental validation using the reference 3-phase machine has been done.

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Effect of Number of Phases on Electromagnetic Torque of Synchronous Machines

Cited by 3 publications

References 4 publications

Performance Analysis of a Rewound Multiphase Synchronous Reluctance Machine

Performance Analysis of a Rewound Multiphase Synchronous Reluctance Machine

Refurbishing three-phase synchronous reluctance machines to multiphase machines

Performance Improvement of Existing Three Phase Synchronous Reluctance Machine: Stator Upgrading to 5-Phase With Combined Star-Pentagon Winding

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