Comparison of Performance of Brushless DC Drives under Direct Torque Control and PWM Current Control

  • Zhu Z. Q. (Department of Electronic and Electrical Engineering) ;
  • Liu Yong (Department of Electronic and Electrical Engineering) ;
  • Howe David (Department of Electronic and Electrical Engineering)
  • Published : 2005.12.01


Direct torque control (DTC) was originally developed for induction machine drives, and, more recently has been applied to permanent magnet brushless AC (BLAC) drives. In this paper, the performance of DTC controlled brushless DC (BLDC) drives is compared with that of PWM current controlled BLDC drives, both with and without current shaping. Both simulation and experimental results are presented, as well as the analysis of the resulting torque waveforms. It is shown that, in addition to exhibiting a fast torque response, a DTC controlled BLDC drive has a significantly lower low-frequency torque ripple than the PWM current controlled BLDC drive without current shaping, and that it is easier to implement than PWM current control with current shaping.


  1. C. S. Berendsen, G. Champenois and A. Bolopion, 'Commutation strategies for brushless DC motors: influence on instant torque,' IEEE Transactions on Power Electronics, Vol.8, No.2, April 1993 pp.231-236
  2. T. S. Kim; S. C. Ahn and D. S. Hyun, 'A new current control algorithm for torque ripple reduction of BLDC motors,' The 27th Annual Conference of the IEEE Industrial Electronics Society, IECON 01, Vol.2, 29th Nov.-2nd Dec. 2001, Denver, CO, USA, pp.1521-1526
  3. D. Grenier, S. Yala, O. Akhrif and L. A. Dessaint, 'Direct torque control of PM AC motor with nonsinusoidal flux distribution using state-feedback linearization techniques,' Proceedings of 24th Annual Conference of IEEE Industrial Electronics Society, IECON98, Vol.3, 31st Aug.-4th Sept.1998, Aachen, Germany, pp.1515-1520
  4. Y. Liu, Z. Q. Zhu and D. Howe, 'Direct torque control of brushless DC drives with reduced torque ripple,' IEEE Transactions on Industry Applications, Vol.41, No.2, March/April, 2005, pp.599-608
  5. T. J. E. Miller, Brushless permanent-magnet and reluctance motor drives, Oxford: Clarendon Press, 1989
  6. L. Zhong, M. F. Rahman, W. Y. Hu and K. W. Lim, 'Analysis of direct torque control in permanent magnet synchronous motor drives,' IEEE Transitions on Power Electronics, Vol. 12, No.3, May, 1997, pp.528-536