Vibrational Forces in Salient Pole Synchronous Machines Considering Tooth Ripple Effects

Traxler-Samek, G.; Lugand, Thomas; Uemori, Mauro K. I.

doi:10.1109/tie.2011.2143382

Cited by 30 publications

(15 citation statements)

References 26 publications

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“…The radial component of the force density f r as expressed by (1) can be written as the contributions of the radial components of the flux density f rr minus the contributions from the tangential flux density components f rt , (2).…”

Section: Analysis Of Radial Force Densitymentioning

confidence: 99%

“…It gives greater freedom of choice when selecting the number of slots, several alternatives for short pitching and it is easier to achieve lower harmonic distortion (i.e. reduced 3rd, 5th, 7th and higher order harmonics) [2].…”

Section: Introductionmentioning

confidence: 99%

“…Often the mmf harmonics are calculated analytically based on the winding layout [8]. The airgap flux density harmonics are then calculated using airgap permeance formulations, where influence of the permeance of the rest of the generator is assumed negligible [2], [7].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of winding layout and airgap length on radial forces in large synchronous hydrogenerators

Engevik

Valavi

Nysveen

2017

2017 20th International Conference on Electrical Machines and Systems (ICEMS)

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Abstract-This paper investigates the flux density and radial force spatial harmonics in large salient pole synchronous hydrogenerators. Vibration due to magnetic forces are mainly caused by low order harmonics in the airgap flux density distribution. The influence of winding layout and airgap length on the lowest order radial force component are analysed. Airgap flux density and radial force density distributions of three different generators are computed using finite element calculations. The flux density components that contributes to the lowest order force component, and the source for these harmonic components, are investigated. It is found that reducing the airgap length leads to a less than proportional increase in the lowest order radial force component. A rearrangement of the winding layout is found to be an effective method for reducing the lowest order radial force component.

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Section: Analysis Of Radial Force Densitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of winding layout and airgap length on radial forces in large synchronous hydrogenerators

Engevik

Valavi

Nysveen

2017

2017 20th International Conference on Electrical Machines and Systems (ICEMS)

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“…Indeed, electrical motors are often controlled using pulse-width modulated voltagesource inverters, which results in higher time-harmonic orders in the current signal. The rising importance of these harmonics has led to a growing interest for harmonic-related phenomena in electrical machines, such as noise [1], [2] and losses [3], [4]. To better understand these phenomena, it is mandatory to have a good understanding of which time-and spatialharmonic combinations exist in the machine and what their physical cause is.…”

Section: Introductionmentioning

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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“…In the case of only eccentricity, a literature survey indicates on intensive studies of methods for calculating UMP, as well as studies on vibrations in machines due to the UMP. To mention a few: [3] and [4] focus on the finite element method (FEM) to find the UMP while [5][6][7][8] consider analytical models for the UMP and perform dynamical analysis and simulations. To the authors knowledge, there are only a few papers published considering higher frequencies of shape deviations, see [4,[9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Small shape deviations causes complex dynamics in large electric generators

Lundström

Grafström

Aidanpää

2014

Eur. Phys. J. Appl. Phys.

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Abstract. We prove that combinations of small eccentricity, ovality and/or triangularity in the rotor and stator can produce complex whirling motions of an unbalanced rotor in large synchronous generators. It is concluded which structures of shape deviations that are more harmful, in the sense of producing complex whirling motions, than others. For each such structure, we derive simplified equations of motions from which we conclude analytically the relation between shape deviations and mass unbalance that yield non-smooth whirling motions. Finally we discuss validity of our results in the sense of modeling of the unbalanced magnetic pull force.

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Vibrational Forces in Salient Pole Synchronous Machines Considering Tooth Ripple Effects

Cited by 30 publications

References 26 publications

Influence of winding layout and airgap length on radial forces in large synchronous hydrogenerators

Influence of winding layout and airgap length on radial forces in large synchronous hydrogenerators

Time- and Spatial-Harmonic Content in Synchronous Electrical Machines

Small shape deviations causes complex dynamics in large electric generators

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