Analysis on Core Loss of Brushless DC Motor Considering Pulse Width Modulation of Inverter

  • Kim, Ki-Chan
  • Received : 2014.07.20
  • Accepted : 2014.09.14
  • Published : 2014.11.01


In this paper, characteristics of blushless direct current (BLDC) motor including core loss are analyzed considering pulse width modulation (PWM) of inverter. Input voltage of BLDC motor due to PWM is calculated considering duty ratio and carrier frequency of inverter in order to control torque or speed of BLDC motor. For the calculation of core loss, the input current with harmonics due to PWM voltage is calculated by using equivalent circuit model of BLDC motor according to switching pattern and carrier frequency. Next, core loss is analyzed by inputting the currents as a source of BLDC motor for FEM. Characteristics including core loss are compared with ones without PWM waveform according to reference speed.


Blushless DC motor;Core loss;Pulse width modulation;Switching frequency


  1. N. Kunihiro, T. Todaka, M. Enokizono, "Loss evaluation of an induction motor model coreby vector magnetic characteristic analysis," IEEE Trans. Magn., vol. 47, no. 5, pp. 1098-1101, May. 2011.
  2. K.Y. Jung, Z. Ren, H.S. Yoon, C.-S. Koh, "Measurement of stator core loss of an induction motor at each manufacturing process," J. Electr. Eng. Technol., vol. 9, No. 4, pp. 1309-1314, 2014.
  3. K. Yamazaki, "Torque and efficiency calculation of an interior permanent magnet motor considering harmonic iron losses of both the stator and rotor," IEEE Trans. Magn., vol. 39, no. 3, pp. 1460-1463, May 2003.
  4. Y. Huang, J. Dong, J. G. Zhu, Y. Guo, "Core loss modeling for permanent magnet motor based on flux variation locus and finite element method," IEEE Trans. Magn., vol. 48, no. 2, pp. 1023-1026, Feb. 2012.
  5. Jian Shi and Tie-Cai Li, "New Method to Eliminate Commutation Torque Ripple of Brushless DC Motor With Minimum Commutation Time, " IEEE Trans.on Indus. Electron., Vol. 60, no. 6, pp. 2139-2146, June 2013.
  6. H. Domeki, Y. Ishihara, C. Kaido, Y. Kawase, S. Kitamura, T. Shimomura, N. Takahashi, T. Yamada, and K. Yamazaki, "Investigation of benchmark model for estimating iron loss in rotating machine," IEEE Trans. Magn., vol. 40, no. 2, pp. 794-797, Mar. 2004.
  7. K. Atallah, Z. Q. Zhu, and D. Howe, "An Improved method for predicting iron losses in brushless permanent magnet motor," IEEE Trans. Magn., vol. 28, no. 5, pp. 2997-2999, Sept. 1992.
  8. K. Yamazaki, S. Watarim, "Loss analysis of permanentmagnet motor considering carrier harmonics of PWM inverter using combination of 2-D and 3-D Finite- Element Method," IEEE Trans. on Magn., vol. 41, No. 5, pp. 1980-1983, May. 2005.


Supported by : National Research Foundation of Korea(NRF)