Optimal Slot Numbers for Magnetic Noise Reduction in Variable-Speed Induction Motors

Although many empirical rules have been established for correctly choosing the number of stator and rotor slots so as to limit the audible magnetic noise level radiated by induction machines, these rules never take into account the stator natural frequencies or the fact that the motor is run at variable speed. In this paper, we present a fast simulation tool for the variable-speed magnetic noise emitted by induction machines, based on fully analytical models. On the basis of these models, we derive and experimentally validate an analytical expression for magnetic vibrations due to slotting reluctance harmonics, confirming the prime importance of slot combination in magnetic noise radiation. We ran simulations on a 700-W squirrel-cage motor in order to quantify the noise emitted by all possible combinations of slot numbers in two- and three-pole pairs, including odd slot numbers. We thus obtained a database that efficiently replaces the old empirical rules for slot combination numbers and helps in designing quiet induction motors. Similar databases can be built for other power ranges.

[1]  Anouar Belahcen,et al.  Magnetoelasticity, magnetic forces and magnetostriction in electrical machines , 2004 .

[2]  P. Brochet,et al.  Characterization and Reduction of Magnetic Noise Due to Saturation in Induction Machines , 2009, IEEE Transactions on Magnetics.

[3]  S. J. Yang,et al.  Low-Noise Electrical Motors , 1981 .

[4]  K. Hameyer,et al.  Deformation Analysis of Induction Machines by Means of Analytical and Numerical Methods , 2008, IEEE Transactions on Magnetics.

[5]  Gabriel Kron,et al.  Induction Motor Slot Combinations Rules to Predetermine Crawling, Vibration, Noise and Hooks in the Speed-Torque Curve , 1931, Transactions of the American Institute of Electrical Engineers.

[6]  Jean Le Besnerais,et al.  Reduction of magnetic noise in PWM-supplied induction machines - low-noise design rules and multi-objective optimization , 2008 .

[7]  Kazuo Tsuboi,et al.  Effect of slot-combination on electromagnetic vibration of squirrel-cage induction motor under loaded condition , 1997, Proceedings of Power Conversion Conference - PCC '97.

[8]  P. L. Alger,et al.  Induction machines, their behavior and uses , 1995 .

[9]  Iqbal Husain,et al.  Radial force calculation and acoustic noise prediction in switched reluctance machines , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).

[10]  J. Le Besnerais,et al.  Characterisation of radial vibration force and vibration behaviour of a pulse-width modulation-fed fractional-slot induction machine , 2009 .

[11]  이건,et al.  Comparison of 12/8 and 6/4 Switched Reluctance Motor : Noise and Vibration Aspects , 2008 .

[12]  M.I. Valla,et al.  A 2-D model of the induction machine: an extension of the modified winding function approach , 2004, IEEE Transactions on Energy Conversion.

[13]  Joseph C. S. Lai,et al.  Acoustic noise of electromagnetic origin in an ideal frequency-converter-driven induction motor , 1994 .

[14]  P. Brochet,et al.  Optimal Slot Opening Width for Magnetic Noise Reduction in Induction Motors , 2009, IEEE Transactions on Energy Conversion.

[15]  J. Le Besnerais,et al.  Characterization of the audible magnetic noise emitted by traction motors in railway rolling stock , 2009 .

[16]  S. P. Verma,et al.  Determination of radial-forces in relation to noise and vibration problems of squirrel-cage induction motors , 1994 .

[17]  A. Belahcen,et al.  Vibrations of rotating electrical machines due to magnetomechanical coupling and magnetostriction , 2006, IEEE Transactions on Magnetics.

[18]  J. Brudny.  Modélisation de la denture des machines asynchrones. Phénomène de résonance , 1997 .

[19]  Guy Friedrich,et al.  Acoustic noise of electromagnetic origin in a fractional‐slot induction machine , 2008 .

[20]  L. Timár-P.,et al.  Noise and vibration of electrical machines , 1989 .

[21]  M. Ito,et al.  Effects of slot combination on acoustic noise from induction motors , 1997 .

[22]  Ion Boldea,et al.  The Induction Machine Handbook , 2001 .

[23]  G. Scutaru,et al.  The magnetic noise of three-phase induction motors with squirrel cage rotors , 2008, 2008 11th International Conference on Optimization of Electrical and Electronic Equipment.

[24]  Jan Melkebeek,et al.  Numerical analysis of the contribution of magnetic forces and magnetostriction to the vibrations in induction machines , 2006 .

[25]  W. Soedel.  Vibrations of shells and plates , 1981 .

[26]  Q. H. Wu,et al.  Reduction of electromagnetic noise in three-phase induction motors , 2002, Proceedings. International Conference on Power System Technology.