Dynamic Analysis of a 3-Phase BLDC Motor Considering Variation of an Air-Gap

공극의 시간변화를 고려한 3 상 BLDC 모터의 동특성 해석

  • 박기선 (LIG NEX1 기계연구센터) ;
  • 임형빈 (한양대학교 대학원 기계공학과) ;
  • 정진태 (한양대학교 기계공학과)
  • Published : 2009.10.01


In this study, vibrations of an electric motor are analyzed when the motor has the interaction between mechanical and electromagnetic behaviors. For this vibration analysis a 3-phase 8-pole brushless DC motor is selected. Vibrations of the motor are influenced by coupled electromechanical characteristics. The variation of air-gap induced by vibration has an influence on the inductance of the motor coil. To analyze dynamic characteristics of the rotor, we studied inductance by the variation of an air-gap. After obtaining the kinetic, potential and magnetic energies for the motor, the equations of motion are derived by using Lagrange's equation. By applying the Newmark time integration method to the equations, the dynamic responses for the displacements and currents are computed.


  1. Jang, G. H. and Chang, J. H., 2002, 'Finite-Element Analysis of an Electromechanical Field of a BLDC Motor Considering Speed Control and Mechanical Flexibility,' IEEE Trans. On Magnetics, Vol.38, No.2, pp. 945-948
  2. Chang, J. H. and Jang, G. H., 2003, 'Electromechanical field analysis of Brushless DC motor due to the driving methods,' The Korean Institute of Power Electronics, pp.659-662
  3. Kim, T. J. and Hwang, S. M., 2000, 'Transient Dynamic Analysis of a Dynamic Eccentric Rotor with Unbalanced Magnetic Forces in BLDC Motors,' Transactions of the Korean Society for Noise and Vibration Engineering, Vol. 10, No. 3, pp. 401-409
  4. Kim, T. J. and Hwang, S. M., 2000, 'Dynamic Behavior Analysis for HDD Spindle Motors with Rotor Eccentricity,' Transactions of the Korean Society for Noise and Vibration Engineering, Vol. 10, No. 6, pp. 977-984
  5. Hendershot J. R. Jr. and Miller, T. J. E., 1994, 'Design of Brushless Permanent-Magnet Motors,' Clarendon, New York
  6. Paul C. Krause and Oleg Wasynczuk., 1989, 'Electromechanical Motion Devices.'
  7. Buxton, J. N., Churchhouse, R. F. and Tayler., A. B., 1990, 'Practical Time-stepping Schemes.'