A New Approach of Minimizing Commutation Torque Ripple for Brushless DC Motor Based on DC–DC Converter Wind Energy Projects

 

ABSTRACT:

Brushless dc motor still suffers from commutation torque ripple, which mainly depends on speed and transient line current in the commutation interval. This paper presents a novel circuit topology and a dc link voltage control strategy to keep incoming and outgoing phase currents changing at the same rate during commutation. A dc–dc single-ended primary inductor converter (SEPIC) and a switch selection circuit are employed in front of the inverter. The desired commutation voltage is accomplished by the SEPIC converter. The dc link voltage control strategy is carried out by the switch selection circuit to separate two procedures, adjusting the SEPIC converter and regulating speed. The cause of commutation ripple is analyzed, and the way to obtain the desired dc link voltage is introduced in detail. Finally, simulation and experimental results show that, compared with the dc–dc converter, the proposed method can obtain the desired voltage much faster and minimize commutation torque ripple more efficiently at both high and low speeds.

KEYWORDS:

  1. Brushless dc motor (BLDCM)
  2. Commutation,
  3. Dc link voltage control
  4. Single-ended primary inductor converter (SEPIC)
  5. Torque ripple

 SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Configuration of BLDCM driving system with a SEPIC converter

EXPECTED SIMULATION RESULTS:

 

Fig. 2. Simulated phase currents at n = 1000 r/min. (a) Without dc link voltage control. (b) With dc link voltage control by a SEPIC converter.

Fig. 3. Simulated phase currents at n = 2500 r/min. (a) Without dc link voltage control. (b) With dc link voltage control by a SEPIC converter.

Fig. 4. Simulated electromagnetic torque at n = 1000 r/min. (a) Without DC link voltage control. (b)With DC link voltage control by a SEPIC converter.

Fig. 5. Simulated electromagnetic torque at n = 2500 r/min. (a) Without dc link voltage control. (b) With dc link voltage control by a SEPIC converter.

 CONCLUSION:

A new circuit topology and control strategy has been proposed to suppress commutation torque ripple of BLDCM in this paper. A SEPIC converter is placed at the input of the inverter, and the desired dc link voltage can be achieved by appropriate voltage switch control. The switch control separates the two procedures, adjustment of SEPIC converter, and regulation of speed so that torque can respond immediately during transient commutation and robustness can be improved. Furthermore, no exact value of the commutation interval T is required, and the proposed method can reduce commutation torque ripple effectively within a wide speed range. Finally, the simulated and measured results show an improved performance of the proposed method.

REFERENCES:

[1] Y.-C. Son, K.-Y. Jang, and B.-S. Suh, “Integrated MOSFET inverter module of low-power drive system,” IEEE Trans. Ind. Appl., vol. 44, no. 3, pp. 878–886, May/Jun. 2008.

[2] A. Sathyan, N. Milivojevic, Y.-J. Lee, M. Krishnamurthy, and A. Emadi, “An FPGA-based novel digital PWM control scheme for BLDC motor drives,” IEEE Trans. Ind. Electron., vol. 56, no. 8, pp. 3040–3049, Aug. 2009.

[3] G. J. Su and J. W. Mckeever, “Low-cost sensorless control of brushless DC motors with improved speed range,” IEEE Trans. Power Electron., vol. 19, no. 2, pp. 296–302, Mar. 2004.

[4] C.-T. Pan and E. Fang, “A phase-locked-loop-assisted internal model adjustable-speed controller for BLDC motors,” IEEE Trans. Ind. Electron., vol. 55, no. 9, pp. 3415–3425, Sep. 2008.

[5] C. Xia, Z. Li, and T. Shi, “A control strategy for four-switch threephase brushless dc motor using single current sensor,” IEEE Trans. Ind. Electron., vol. 56, no. 6, pp. 2058–2066, Jun. 2009.

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