Hybrid converter topology for reducing torque ripple of BLDC motor



This study investigates the torque ripple performance of brushless DC (BLDC) motor drive system by integrating both modified single-ended primary inductor converter (SEPIC) and silicon carbide metal–oxide–semiconductor field-effect transistor based three-level neutral-point-clamped (NPC) inverter. In BLDC motor, the high commutation torque ripple is an important origin of vibration, speed ripple and prevents the use of the BLDC motor drive system in high-performance and high-precision applications. For torque ripple reduction, the modified SEPIC converter is employed at the entrance of the three-level NPC inverter, which regulates the DC-link voltage according to the motor speed. Moreover, the three-level NPC inverter is employed as a second-stage converter to suppress current ripple for further torque ripple reduction. Finally, the performance of the proposed hybrid converter topology is verified by simulation and laboratory experimental results.




(a) Proposed converter topology


Fig. 2 Phase current and torque waveforms

(a) Phase current and torque waveforms from simulation at 2500 rpm and 0.825 N m, (b) Phase current and torque waveforms from simulation at 2500 rpm and 0.825 N m, (c) Phase current and torque waveforms from simulation at 6000 rpm and 0.825 N m, (d) Phase current and torque waveforms from simulation at 6000 rpm and 0.825 N m


A novel hybrid circuit topology has been proposed in this paperwhich is built by a modified SEPIC converter and a SiC-MOSFETbasedthree-level NPC converter for minimising torque ripple in aBLDC motor drive system. For efficient reduction of torque ripple,the first stage is the modified SEPIC converter that lifts the DClinkvoltage to the desired value based on the motor speedmeasurement. For further torque ripple reduction, the three-levelNPC inverter is employed as the second-stage converter tosuppress current ripple. Experimental results show that theproposed hybrid converter topology can suppress the torque rippleto 14.6% at the speed of 6000 rpm, commutation torque ripple isreduced substantially and produce smooth torque waveform thanthe BLDC motor driven by the two-level, three-level NPC, twolevelinverter with DC-link voltage control, and two-level inverterwith SEPIC converter and switch selection circuit topologies.


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[2] Carlson, R., Lajoie-Mazenc, M., Fagundes, J.C.D.S.: ‘Analysis of torqueripple due to phase commutation in brushless dc machines’, IEEE Trans. Ind.Appl., 1992, 28, (3), pp. 632–638

[3] Lee, S.K., Kang, G.H., Hur, J., et al.: ‘Stator and rotor shape designs ofinterior permanent magnet type brushless DC motor for reducing torquefluctuation’, IEEE Trans. Magn., 2012, 48, pp. 4662–4665

[4] Seo, U.J., Chun, Y.D., Choi, J.H., et al.: ‘A technique of torque ripplereduction in interior permanent magnet synchronous motor’, IEEE Trans.Magn., 2011, 47, (10), pp. 3240–3243

[5] Murai, Y., Kawase, K., Ohashi, K., et al.: ‘Torque ripple improvement forbrushless DC miniature motors’, IEEE Trans. Ind. Appl., 1989, 25, (3), pp.441–450

One thought on “Hybrid converter topology for reducing torque ripple of BLDC motor

  1. Good work sir,
    You are doing so much work in bldc motor drive. I am not understanding where is the fault between both of them you can not give our work still regarding base model , extension part, and paper publication part. You think sir from 2016 September to 2018 January this much time is passed but you can not give any things. How people believe on you and why? You said sir lastely you are interested for our work or not, because we have not enough time and we people are looking for another option also, last time I am also ask to you how much time you require for completion of our work but you did not reply , so that I communicate after very long time to you. I hope you reply sir .
    Saharan Kumar

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