Structural Design for Vibration Reduction in Brushless DC Stator

  • Jafarboland, Mehrdad (Malek-Ashtar University of Technology) ;
  • Farahabadi, Hossein Bagherian (Malek-Ashtar University of Technology)
  • Received : 2016.11.15
  • Accepted : 2017.05.16
  • Published : 2017.09.01


Reducing the noise and vibration of the BLDC motors is very essential for some special applications. In this paper, a new structural design is introduced to increase the natural frequencies of the stator in BLDC motors as increasing the natural frequencies can reduce the severe effects of the structural resonances, including high levels of noise and vibration. The design is based on placing a single hole on definite regions at the stator cross sectional area (each region contains one tooth and its upper parts in the stator yoke) in an optimum way by which the natural frequencies at different modes are shifted to the higher values. The optimum diameter and locations for the holes are extracted by the Response Surface Methodology (RSM) and the modal analyses in the iterative process are done by Finite Element Method (FEM). Moreover, the motor performance by the optimum stator structure is analyzed by FEM and compared with the prototype motor. Preventing the stator magnetic saturation and the motor cogging torque enhancement are the two constraints of the optimization problem. The optimal structural design method is applied experimentally and the validity of the design method is confirmed by the simulated and experimental results.


BLDC stator;Hole placement;Modal analysis;Natural frequencies;Structural design


  1. D. Y. Kim, J. K. Nam and G. H. Jang, "Reduction of Magnetically Induced Vibration of a Spoke-Type IPM Motor using Magnetomechanical Coupled Analysis and Optimization," IEEE Trans. Magnetics, vol. 49, no. 9, pp. 5097-5105, Sep. 2012.
  2. Hong-Seok Ko and Kwang-Joon Kim, "Characterization of Noise and Vibration Sources in Interior Permanent-Magnet Brushless DC Motors," IEEE Trans. Magnetics, vol. 40, no. 6, pp. 3482-3489, Nov. 2004.
  3. Sang-Ho Lee, Jung-Pyo Hong, Sang-Moon Hwang, Woo-Taik Lee, Ji-Young and Youbg-Kyoun Kim, "Optimal Design for Noise Reduction in Interior Permanent-Magnet Motor," IEEE Trans. Industry Applications, vol. 45, no. 6, pp. 1954-1960, Nov./Dec. 2009.
  4. D. Y. Kim, G. H. Jang and J. K. Nam, "Magnetically Induced Vibrations in an IPM Motor due to Distorted Magnetic Forces Arising from Flux Weakening Control," IEEE Trans. Magnetics, vol. 49, no. 7, pp. 3929-3932, Nov. 2013.
  5. Ji-Min Kim, Tao Sun, Sang-Ho Lee, Do-Jin Kim, Jung-Pyo Hong, "Evaluation and Improved Design about Acoustic Noise and Vibration in IPMSM," in Proceeding of IEEE Electrical Machines and Systems Conference, Incheon, South Korea, Oct. 2010.
  6. K. H. Yim, J. W. Jang, G. H. Jang, M. G. Kim, K. N. Kim, "Forced Vibration Analysis of an IPM Motor for Electrical Vehicles due to Magnetic Force," IEEE Trans. Magnetics, vol. 48, no. 11, pp. 2981-2984, Nov. 2012.
  7. P. Vijayraghavan and R. Krishnan, "Noise in Electric Machines: a Review," IEEE Trans. Industry Applications, vol. 35, no. 5, pp. 1007-1013, Apr. 1999.
  8. Jacek F. Gieras, Chong Wang and Joseph Cho Lai, Noise of Polyphase Electric Motors. Boca Raton, FL: CRC Press, 2006.
  9. Jin Hur, Jin-Wook Reu, Byeong-Woo Kim and Gyu-Hong Kang, "Vibration Reduction of IPMType BLDC Motor Using Negative Third Harmonic Elimination Method of Air-Gap Flux Density," IEEE Trans. Industry Applications, vol. 47, no. 3, pp. 1300-1309, May/June 2011.
  10. Arthur W. Leissa, Vibration of Shells. New York, NY, USA: Acoustic Society of America, American Institute of Physics, 1993.
  11. Werner Soedel, Vibrations of Shells and Plates. NY: Marcel Dekker, 1993.
  12. S. J. Yang, Low-Noise Electrical Motors. Oxford, United Kingdom: Clarendon Press, 1981.
  13. Tao Sun, Ji-Min Kim, Geun-Ho Lee, Jung-Pyo Hong and Myung-Ryul Choi, "Effect of Pole and Slot Combination on Noise and Vibration in Permanent Magnet Synchronous Motor," IEEE Trans. Magnetics, vol. 47, no. 5, pp. 1038-1041, May 2011.