Commutation Torque Ripple Reduction in Brushless DC Motor Drives Using a Single DC Current Sensor

 

ABSTRACT:

This paper presents a comprehensive study on reducing commutation torque ripples generated in brushless dc motor drives with only a single dc-link current sensor provided. In such drives, commutation torque ripple suppression techniques that are practically effective in low speed as well as high speed regions are scarcely found. The commutation compensation technique proposed here is based on a strategy that the current slopes of the incoming and the outgoing phases during the commutation interval can be equalized by a proper duty-ratio control. Being directly linked with deadbeat current control scheme, the proposed control method accomplishes suppression of the spikes and dips superimposed on the current and torque responses during the commutation intervals of the inverter. Effectiveness of the proposed control method is verified through simulations and experiments.

 KEYWORDS:

  1. Brushless dc motor drives
  2. Commutation torque ripple reduction
  3. Single dc current sensor

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

 

Fig. 1. Basic configuration of trapezoidal brushless dc motor drives with dc link current controlled.

EXPECTED SIMULATION RESULTS:

 

(a)

(b)

(c)

Fig. 2. Simulation results in the low speed range: (a) phase currents, (b)

dc-link current, and (c) commutation torque ripple.

(a)

(b)

(c)

Fig. 3. Simulation results in the high speed range: (a) phase currents, (b)

dc-link current, and (c) commutation torque ripple.

 CONCLUSION:

In this paper, a commutation torque ripple reduction method has been proposed for brushless dc motor drives using a single dc current sensor. In such drives, the dc-link current sensor cannot give any information corresponding to the motor currents during the phase current commutation intervals. Using the commutated phase current waveforms synthesized from the measured dc current, a duty ratio control strategy has been devised to equalize the two mismatched commutation time intervals. By being directly linked with the deadbeat current control scheme, the proposed control method accomplishes successful suppression of the spikes and dips superimposed on the current and torque responses during the commutation intervals. This scheme shows attractive effectiveness in the low and the high speed regions through simulations and experiments.

REFERENCES:

[1] T. M. Jahns andW. L. Soong, “Pulsating torque minimization techniques for permanent magnet AC motor drives—a review,” IEEE Trans. Ind. Electron., vol. 43, pp. 321–330, Apr. 1996.

[2] R. Carlson, M. Lajoie-Mazenc, and J. C. S. Fagundes, “Analysis of torque ripple due to phase commutation in brushless DC machines,” IEEE Trans. Ind. Applicat., vol. 28, pp. 632–638, May/June 1992.

[3] K.-W. Lee, J.-B. Park, H.-G. Yeo, J.-Y. Yoo, and H.-M. Jo, “Current control algorithm to reduce torque ripple in brushless dc motors,” in Proc. Int. Conf. Power Electron., 1998, pp. 380–385.

[4] J. Cros, J. M. Vinassa, S. Clenet, S. Astier, and M. Lajoie-Mazenc, “A novel current control strategy in trapezoidal EMF actuators to minimize torque ripples due to phases commutations,” in Proc. Eur. Power Electron. Conf., 1993, pp. 266–271.

[5] Y. Murai,Y. Kawase, K. Ohashi, K. Nagatake, and K. Okuyama, “Torque ripple improvement for brushless DC miniature motors,” IEEE Trans. Ind. Applicat., vol. 25, pp. 441–450, May/June 1989.

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