532:
175:(also called cogging torque for permanent magnet synchronous machines in open circuit), which represents the harmonic variations of electromagnetic torque, is a dynamic force creating torsional vibrations of both rotor and stator. The torsional deflection of a simple cylinder cannot radiate efficiently acoustic noise, but with particular boundary conditions the stator can radiate acoustic noise under torque ripple excitation. Structure-borne noise can also be generated by torque ripple when rotor shaft line vibrations propagate to the frame and shaft line.
540:
234:
146:
These phenomena can potentially generate vibrations of the ferromagnetic, conductive parts, coils and permanent magnets of electrical, magnetic and electromechanical device, resulting in an audible sound if the frequency of vibrations lies between 20 Hz and 20 kHz, and if the sound level is
83:
The phenomenon is also called audible magnetic noise, electromagnetic acoustic noise, lamination vibration or electromagnetically induced acoustic noise, or more rarely, electrical noise, or "coil noise", depending on the application. The term electromagnetic noise is generally avoided as the term is
565:
The resonance effect of magnetic vibration with a structural mode can be illustrated using a tuning fork made of iron. A prong of the tuning fork is wound with a coil fed by a variable frequency power supply. A variable flux density circulates between the two prongs and some dynamic magnetic forces
229:
In radial flux rotating electric machines, resonance due to electromagnetic forces is particular as it occurs at two conditions: there must be a match between the exciting
Maxwell force and the stator or rotor natural frequency, and between the stator or rotor modal shape and the exciting Maxwell
220:
are also subject to large electrostatic forces. When the capacitor voltage/current waveform is not constant and contains time harmonics, some harmonic electric forces appear and acoustic noise can be generated. Ferroelectric capacitors also exhibit a piezoelectric effect that can be source of
996:
Zhu, Z. Q., Xia, Z. P., Wu, L. J., & Jewell, G. W. (2009). Influence of slot and pole number combination on radial force and vibration modes in fractional slot PM brushless machines having single- and double-layer windings. 2009 IEEE Energy
Conversion Congress and Exposition, ECCE 2009,
127:
material in electric machines; they are also responsible of the attraction or repulsion of two magnets facing each other. Magnetostriction forces are concentrated inside the ferromagnetic material itself. Lorentz or
Laplace forces act on conductors plunged in an external magnetic field.
1022:
Torregrossa, D., Khoobroo, A., & Fahimi, B. (2012). Prediction of acoustic noise and torque pulsation in PM synchronous machines with static eccentricity and partial demagnetization using field reconstruction method. IEEE Transactions on
Industrial Electronics, 59(2), 934–944.
241:
As an example a resonance with the elliptical modal shape of the stator can occur if the force wavenumber is 2. Under resonance conditions, the maxima of the electromagnetic excitation along the airgap and the maxima of the modal shape displacement are in phase.
674:
Carmeli, M. S., Castelli Dezza, F., & Mauri, M. (2006). Electromagnetic vibration and noise analysis of an external rotor permanent magnet motor. International
Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), 1028–33.
547:
A varying electromagnetic force can be produced either by a moving source of DC magnetic field (e.g. rotating permanent magnet or rotating coil supplied with DC current), or by a steady source of AC magnetic field (e.g. a coil fed by a variable current).
158:
The frequency of the noise depends on the nature of electromagnetic forces (quadratic or linear function of electrical field or magnetic field) and on the frequency content of the electromagnetic field (in particular if a DC component is present or not).
728:
Devillers E., Le
Besnerais J., Regniez M. and Hecquet M., (2017). Tangential effects on magnetic vibrations of induction machines using subdomain method and electromagnetic vibration synthesis, Proceedings of IEMDC 2017 Conference, Miami, USA.
178:
Some tangential magnetic force harmonics can directly create magnetic vibrations and acoustic noise when applied to the stator teeth: tangential forces create a bending moment of the stator teeth, resulting in radial vibrations of the yoke.
269:
It is generally considered as a weakly coupled problem: the deformation of the structure under electromagnetic forces is assumed not to change significantly the electromagnetic field distribution and the resulting electromagnetic stress.
171:, which can be calculated as the average value of the Maxwell stress tensor along the airgap, is one consequence of electromagnetic forces in electric machines. As a static force, it does not create vibrations nor acoustic noise. However
195:
In inductors, also called reactors or chokes, magnetic energy is stored in the airgap of the magnetic circuit, where large
Maxwell forces apply. Resulting noise and vibrations depend on airgap material and magnetic circuit geometry.
709:
Tan Kim A. (2013). Contribution à l'étude du bruit acoustique d'origine magnétique en vue de la conception optimale de machines synchrones à griffes pour application automobile. PhD thesis, Université de
Technologie de Compiègne,
1009:
Le
Besnerais, J., Lanfranchi, V., Hecquet, M., Lemaire, G., Augis, E., & Brochet, P. (2009). Characterization and Reduction of Magnetic Noise Due to Saturation in Induction Machines. IEEE Transactions on Magnetics.
556:
This animation illustrates how a ferromagnetic sheet can be deformed due to the magnetic field of a rotating magnet. It corresponds to an ideal one pole pair permanent magnet synchronous machine with a slotless stator.
92:
describes electrical perturbations occurring in electronic circuits, not sound. For the latter use, the terms electromagnetic vibrations or magnetic vibrations, focusing on the structural phenomenon are less ambiguous.
962:
Le
Besnerais, J., Lanfranchi, V., Hecquet, M., & Brochet, P. (2010). Characterization and Reduction of Audible Magnetic Noise Due to PWM Supply in Induction Machines. IEEE Transactions on Industrial Electronics.
604:
Le Besnerais, J., Lanfranchi, V., Hecquet, M., & Brochet, P. (2010). Characterization and Reduction of Audible Magnetic Noise Due to PWM Supply in Induction Machines. IEEE Transactions on Industrial Electronics.
285:
using electromagnetic (e.g. Flux, Jmag, Maxwell, Opera), structural (e.g. Ansys Mechanical, Nastran, Optistruct) and acoustic (e.g. Actran, LMS, Sysnoise) numerical software together with dedicated coupling
1035:
Le Besnerais, J. (2015). Effect of lamination asymmetries on magnetic vibrations and acoustic noise in synchronous machines. In 2015 18th International Conference on Electrical Machines and Systems (ICEMS).
687:
Le Besnerais, J. (2015). Effect of lamination asymmetries on magnetic vibrations and acoustic noise in synchronous machines. In 2015 18th International Conference on Electrical Machines and Systems (ICEMS).
204:
In transformers magnetic noise and vibrations are generated by several phenomena depending on the load case which include Lorentz force on the windings, Maxwell forces in the joints of the laminations, and
656:
van der Giet, M., (2011). Analysis of electromagnetic acoustic noise excitations – a contribution to low-noise design and to the auralization of electrical machines, RWTH Aachen University, Shaker Verlag.
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appear between the two prongs at twice the supply frequency. When the exciting force frequency matches the fundamental mode of the tuning fork close to 400 Hz, a strong acoustic resonance occurs.
733:
424:: if electromagnetic forces are not balanced, a non-zero net magnetic force appears on stator and rotor. This force can excite the bending mode of the rotor and create additional vibration and noise.
950:
Le Besnerais, J. (2008). Reduction of magnetic noise in PWM-supplied induction machines − low-noise design rules and multi-objective optimization. PhD Thesis, Ecole Centrale de Lille, Lille, France.
824:
Le Besnerais, J. (2008). Reduction of magnetic noise in PWM-supplied induction machines − low-noise design rules and multi-objective optimization. PhD Thesis, Ecole Centrale de Lille, Lille, France.
375:
In such device, dynamic electromagnetic forces come from variations of magnetic field, which either comes from a steady AC winding or a rotating DC field source (permanent magnet or DC winding).
719:
De Madinabeitia I. G, (2016). Analysis of force and torque harmonics spectrum in an induction machine for automotive NVH Purposes. Master's thesis, University of Technology of Chalmers, Sweden.
975:
Le Besnerais, J., Lanfranchi, V., Hecquet, M., & Brochet, P. (2009). Optimal Slot Numbers for Magnetic Noise Reduction in Variable-Speed Induction Motors. IEEE Transactions on Magnetics.
748:
M. Rossi and J. Le Besnerais, Vibration Reduction of Inductors Under Magnetostrictive and Maxwell Forces Excitation, in IEEE Transactions on Magnetics, vol. 51, no. 12, pp. 1–6, Dec. 2015.
330:: the braking resistors of electric trains, used to dissipate electrical power when the catenary is not receptive during braking, can make electromagnetically induced acoustic noise
182:
Besides tangential force harmonics, Maxwell stress also includes radial force harmonics responsible for radial vibrations of the yoke, which in turn can radiate acoustic noise.
581:
760:
Arturi, C.M., 1992. Force calculation in transformer windings under unbalanced MMFs by a non-linear finite element code. IEEE transactions on magnetics, 28(2), pp.1363-1366.
123:(also called Laplace force). Maxwell forces, also called reluctances forces, are concentrated at the interface of high magnetic reluctivity changes, e.g. between air and a
987:
Verez, G., Barakat, G., Amara, Y., Bennouna, O., & Hoblos, G. (n.d.). Impact of Pole and Slot Combination on Noise and Vibrations of Flux-Switching PM Machines, (1).
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Weiser, B., Pfützner, H., & Anger, J. (2000). Relevance of Magnetostriction and Forces for the Generation of Audible Noise of Transformer Cores, 36(5), 3759–3777.
779:
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Belahcen, A. (2004). Magnetoelasticity, magnetic forces and magnetostriction in electrical machines. PhD thesis, Helsinki University of Technology, Finland.
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add some glue (e.g. a layer of glue is often added on the top of television coils ; over the years, this glue degrades and the sound level increases)
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M. Hurkala, Noise analysis of high voltage capacitors and dry-type air-core reactors. Doctoral dissertation, Aalto University, Finland, 2013
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high enough to be heard (e.g. large surface of radiation and large vibration levels). Vibration level is increased in case of a mechanical
665:
Finley, W. R., Hodowanec, M. M., & Holter, W. G. (1999). An Analytical Approach to Solving Motor Vibration Problems, 36(5), 1–16.
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Rotating devices include radial and axial flux rotating electric machines used for electrical to mechanical power conversion such as
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The simulation of electromagnetically induced noise and vibrations is a multiphysic modeling process carried in three steps:
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https://eomys.com/recherche/publications/article/tangential-effects-on-magnetic-vibrations-and-acoustic-noise-of-induction
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reducing the magnitude of electromagnetic excitations, independently of the structural response of the electrical machine
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28:
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The harmonic electromagnetic forces responsible for magnetic noise and vibrations in a healthy machine can come from
340:, "coil noise" is that part of total system noise attributed to the receiving coil, due to its non-zero temperature.
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Static devices include electrical systems and components used in electric power storage or power conversion such as
337:
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100:, which describes how a mechanical vibration or acoustic noise can induce an undesired electrical perturbation.
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of the active component (magnetic circuit, electromagnetic coil or electrical circuit) or of its enclosure.
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using multiphysics numerical simulation software environment (e.g. Comsol Multiphysics, Ansys Workbench)
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838:"MANATEE software (Magnetic Acoustic Noise Analysis Tool for Electrical Engineering), official website"
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Electromagnetic forces can be defined as forces arising from the presence of an electromagnetic field.
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Example of modal shape number 2 of a stator; movements have been exaggerated for presentation purposes
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reducing the magnitude of the structural response, independently of the electromagnetic excitations
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In a faulty machine, additional noise and vibrations due to electromagnetic forces can come from
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The assessment of audible magnetic noise in electrical machines can be done using three methods:
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Acoustic noise and vibrations due to electromagnetic forces can be seen as the reciprocal of
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Electromagnetic forces in the presence of a magnetic field include equivalent forces due to
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Deflection of a ferromagnetic cylinder due to a rotating permanent magnet excitation field
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Electromagnetic noise and vibration mitigation techniques in electrical machines include:
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Equivalent electromagnetic forces due to the presence of an electrical field can involve
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Unbalanced Magnetic Pull (UMP) describes the electromagnetic equivalence of mechanical
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Video of a resonating tuning fork magnetically excited by a variable frequency current
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using dedicated electromagnetic and vibro-acoustic simulation software (e.g. MANATEE )
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isolate the coil from the rest of the device to minimize structure-borne noise
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audible noise. This phenomenon is known as the "singing capacitor" effect.
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avoiding resonances match between stator and electromagnetic excitations
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Video of a tuning fork magnetically excited by a fixed frequency current
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620:"Transversal Motion in Transformer Laminations as a Cause of Noise"
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implementing pole shaping / pole shifting / pole pairing techniques
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Examples of device subject to electromagnetic noise and vibrations
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harmonic wavenumber (periodicity of the force along the airgap).
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Video of a ferromagnetic cylinder deformed by a rotating magnet
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Reduction of magnetic noise and vibrations in electric machines
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Example of magnetic noise coming from a subway electric motor
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Sources of magnetic noise and vibrations in electric machines
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increasing the frequency outside the audible frequency range
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implementing harmonic current injection or spread spectrum
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choosing the right slot/pole combination and winding design
151:, when electromagnetic forces match with a structural mode
76:. The hissing of high voltage transmission lines is due to
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change the shape of the coil (e.g. change coil shape to a
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Electromagnetic noise and vibrations in passive components
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Electromagnetic noise and vibrations in electric machines
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using notches / flux barriers on the stator or the rotor
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Set-up of the electromagnetically excited tuning fork
457:occurring between electromagnetic excitations and
428:Reduction of electromagnetic noise and vibrations
624:The Journal of the Acoustical Society of America
262:calculation of the resulting magnetic vibrations
561:Acoustic resonance by a variable frequency coil
552:Forced vibration by a rotating permanent magnet
952:https://hal.archives-ouvertes.fr/tel-00348730/
826:https://hal.archives-ouvertes.fr/tel-00348730/
8:
404:mechanical static and dynamic eccentricities
677:http://doi.org/10.1109/SPEEDAM.2006.1649919
265:calculation of the resulting magnetic noise
88:, dealing with radio frequencies. The term
60:. Some examples of this noise include the
42:electromagnetically excited acoustic noise
34:Electromagnetically induced acoustic noise
1038:http://doi.org/10.1109/icems.2015.7385319
750:https://doi.org/10.1109/TMAG.2015.2469643
690:http://doi.org/10.1109/icems.2015.7385319
259:calculation of the electromagnetic forces
1012:http://doi.org/10.1109/tmag.2008.2012112
999:http://doi.org/10.1109/ECCE.2009.5316553
977:http://doi.org/10.1109/tmag.2009.2020736
1025:http://doi.org/10.1109/TIE.2011.2151810
965:http://doi.org/10.1109/tie.2009.2029529
607:http://doi.org/10.1109/tie.2009.2029529
597:
505:Coil noise mitigation actions include:
225:Resonance effect in electrical machines
810:: CS1 maint: archived copy as title (
803:
618:Hasson, Sol; Shulman, Yechiel (1967).
516:rather than a traditional coil shape)
7:
887:"Maxwell software official website"
915:"Comsol software official website"
14:
929:"Ansys software official website"
901:"Opera software official website"
575:PMSM motor (traction application)
873:"Jmag software official website"
859:"Flux software official website"
274:Application to electric machines
474:skewing the stator or the rotor
443:in electrical machines include
52:directly produced by materials
1:
86:electromagnetic compatibility
68:, the whine of some rotating
44:, or more commonly known as
29:Electromagnetic interference
736:September 15, 2017, at the
209:inside the laminated core.
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527:Experimental illustrations
338:magnetic resonance imaging
18:
501:Reduction of "coil noise"
56:under the excitation of
19:Not to be confused with
570:Examples of audio files
416:missing magnetic wedges
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388:Pulse-width modulation
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58:electromagnetic forces
1096:Mechanical vibrations
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441:mitigation techniques
390:supply of the machine
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141:reverse piezoelectric
113:Maxwell stress tensor
84:used in the field of
16:Type of audible sound
246:Numerical simulation
636:1967ASAJ...41.1413H
396:magnetic saturation
104:General explanation
25:Noise (electronics)
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422:rotating unbalance
359:synchronous motors
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644:10.1121/1.1910500
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370:reluctance motors
365:or DC wound rotor
363:permanent magnets
153:natural frequency
80:, not magnetism.
74:fluorescent lamps
72:, or the buzz of
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254:
240:
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200:Transformers
194:
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98:microphonics
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997:3443–3450.
490:increasing
251:Methodology
1075:Categories
1067:on YouTube
1061:on YouTube
1055:on YouTube
796:August 31,
592:References
484:strategies
455:resonances
323:capacitors
218:Capacitors
213:Capacitors
46:coil whine
1081:Acoustics
368:switched
328:resistors
308:inductors
191:Inductors
149:resonance
143:effects.
64:, hum of
62:mains hum
54:vibrating
38:vibration
806:cite web
734:Archived
710:France.
632:Bibcode
492:damping
286:methods
169:torque
1106:Sound
1091:Noise
790:(PDF)
783:(PDF)
361:with
336:: in
334:coils
48:, is
36:(and
845:2017
812:link
798:2017
139:and
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640:doi
482:PWM
439:NVH
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27:or
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