Commutation Torque Ripple Reduction in BLDC Motor Using Modified SEPIC Converter and Three-level NPC Inverter

ABSTRACT:

This paper presents a new power converter topology to suppress the torque ripple due to the phase current commutation of a brushless DC motor (BLDCM) drive system. A combination of a 3-level diode clamped multilevel inverter (3-level DCMLI), a modified single-ended primary-inductor converter (SEPIC), and a dc-bus voltage selector circuit are employed in the proposed torque ripple suppression circuit. For efficient suppression of torque pulsation, the dc-bus voltage selector circuit is used to apply the regulated dc-bus voltage from the modified SEPIC converter during the commutation interval. In order to further mitigate the torque ripple pulsation, the 3-level DCMLI is used in the proposed circuit. Finally, simulation and experimental results show that the proposed topology is an attractive option to reduce the commutation torque ripple significantly at low and high speed applications.

KEYWORDS:

  1. Brushless direct current motor (BLDCM),
  2. Dc-bus voltage control
  3. Modified single-ended primary-inductor converter
  4. Level diode clamped multilevel inverter (3-level DCMLI)
  5. Torque ripple

 SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

 

Fig. 1. Proposed converter topology with a dc-bus voltage selector circuit for BLDCM

 EXPECTED SIMULATION RESULTS:

 

Fig. 2. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 3 Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

 

Fig. 4 Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and switch a selection circuit. (d) BLDCM fed by proposed topology.

Fig. 5 Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology

Fig. 6. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 7 Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology

CONCLUSION:

In this paper, a commutation torque ripple reduction circuit has been proposed using 3-level DCMLI with modified SEPIC converter and a dc-bus voltage selector circuit. A laboratory-built drive system has been tested to verify the proposed converter topology. The suggested dc-bus voltage control strategy is more effective in torque ripple reduction in the commutation interval. The proposed topology accomplishes the successful reduction of torque ripple in the commutation period and experimental results are presented to compare the performance of the proposed control technique with the conventional 2-level inverter, 3-level DCMLI, 2-level inverter with SEPIC converter and the switch selection circuit-fed BLDCM. In order to obtain significant torque ripple suppression, quietness and higher efficiency, 3-level DCMLI with modified SEPIC converter and the voltage selector circuit is a most suitable choice to obtain high-performance operation of BLDCM. The proposed topology may be used for the torque ripple suppression of BLDCM with the very low stator winding inductance.

REFERENCES:

[1] N. Milivojevic, M. Krishnamurthy, Y. Gurkaynak, A. Sathyan, Y.-J. Lee, and A. Emadi, “Stability analysis of FPGA-based control of brushless DC motors and generators using digital PWM technique,” IEEE Trans. Ind. Electron., vol. 59, no. 1, pp. 343–351, Jan. 2012.

[2] X. Huang, A. Goodman, C. Gerada, Y. Fang, and Q. Lu, “A single sided matrix converter drive for a brushless dc motor in aerospace applications,” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3542–3552, Sep. 2012.

[3] X. Huang, A. Goodman, C. Gerada, Y. Fang, and Q. Lu, “Design of a five-phase brushless DC motor for a safety critical aerospace application,” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3532-3541, Sep. 2012.

[4] J.-G. Lee, C.-S. Park, J.-J. Lee, G. H. Lee, H.-I. Cho, and J.-P. Hong, “Characteristic analysis of brushless motor condering drive type,” KIEE, pp. 589-591, Jul. 2002.

[5] T. H. Kim and M. Ehsani, “Sensorless control of BLDC motors from near-zero to high speeds,” IEEE Trans. Power Electron., vol. 19, no. 6, pp. 1635–1645, Nov. 2004.

 

 

A New BLDC Motor Drives Method Based on BUCK Converter for Torque Ripple Reduction

ABSTRACT:

This paper presents a comprehensive analysis on torque ripples of brushless dc motor drives in conduction region and commutation region. A novel method for reducing the torque ripple in brushless dc motors with a single current sensor has been proposed by adding BUCK converter in the front of 3-phase inverter.In such drives, torque ripple suppression technique is theoretically effective in commutation region as well as conduction region. Effectiveness and feasibility of the proposed control method is verified through experiments.

KEYWORDS:

  1. Brushless dc motor
  2. Torque ripple
  3. Conduction region
  4. Commutation region

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig1. The new proposed circuit configuration

EXPECTED SIMULATION RESULTS:

 

Fig.2. The 2-phase current-waveforms of conventional modulation mode

Fig.3. The 2-phase current-waveforms of new proposed modulation mode

Fig.4.The commutation current-waveforms of conventional modulation mode

Fig.5.The commutation current-waveforms of new proposed modulation mode

CONCLUSION:

In this paper,a new torque ripple reduction method based on buck converter has been proposed for brushless dc motor drives using a single dc current sensor. In such control method, the dc-link current sensor can give correct information corresponding to the motor phase currents to eliminate torque ripples in conduction region. Meanwhile, torque ripples have been attenuated effectively during commutation region. Subsequently effectiveness and feasibility of the proposed control method are verified through experiments.

REFERENCES:

[1] Joong-Ho Song and Ick Choy, “Commutation torque ripple reduction in brushless DC motor drives using a single DC current sensor,”IEEE Trans. on Power Electronics,vol. 19, No.2 ,pp.312-319,March 2004.

[2] Byoung-Hee Kang,Choel-Ju Kim,Hyung-Su Mok and Gyu-Ha Choe, “Analysis of torque ripple in BLDC motor with commutation time,”Proceedings of IEEE,vol.2,pp.1044-1048, June 2001.

[3] Carlson R,Lajoie-Mazenc M and Fagundes J.C.d.S, “Analysis of torque ripple due to phase communtation in brushless DC machines,”IEEE Trans. on Industry Applications,vol.28,no.3, pp.632-638,May-June 1992.

[4] Luk P.C.K and Lee C.K, “Efficient modeling for a brushless DC motor drive,”International Conference on Industrial Electronics,Control and Instrumentation,vol.1,pp.188-191, September 1994.

[5] Lei Hao,Toliyat,H.A, “BLDC motor full speed range operation including the flux-weakening region,”IEEE-IAS Annual Meeting,vol.1,pp.618-624, Octorber 2003.

Reduction of Commutation Torque Ripple in a Brushless DC Motor Drive

 

ABSTRACT:

This paper describes the reduction in torque ripple due to phase commutation of brushless dc motors. With two-phase 1200 electrical conduction for the inverter connected to the conventional three-phase BLDC machine, the commutation torque ripple occurs at every 60 electrical degrees when a change over from one phase to another occurs. This effect increases the commutation time at higher speeds which increases the torque ripple. The torque ripple is reduced by changing the switching mode from 1200 to a dual switching mode with 1200 switching at lower speeds and 1800 electrical for the inverter at higher speeds.

KEYWORDS:

  1. Brushless dc motor
  2. Current commutation
  3. Torque ripple
  4. Electric vehicle

 SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

 

Fig. 1. PWM inverter and equivalent circuit of BLDC motor

EXPECTED SIMULATION RESULTS:

 

Fig.2. (a) Relative torque ripple amplitude and (b) The duration of commutation time

 

CONCLUSION:

This paper has presented an analytical study of torque ripple comparison due to commutation of phase currents in a brushless dc motor for both 1200 and 1800 conduction modes. The results have been validated by simulation and experimental verification. In three-phase switching mode at high speeds the torque ripple and losses are minimized and therefore the efficiency of the machine is increased. But the same cannot be achieved at low speed in this mode. On the other hand, the 1200 situation is exactly opposite. Thus a composite switching scheme is proposed for satisfactory operation of the machine at all speeds. The effectiveness of the method is validated by suitable experiments.

REFERENCES:

[1] T. Li, and G. Slemon, “Reduction of cogging torque in permanent magnet motors,” IEEE Trans. on Magnetics, vol.24, no.6, pp.2901-2903, Nov. 1988.

[2] R. Carlson, M. Lajoie-Mazenc, and J.C.D.S. Fagundes, “Analysis of torque ripple due to phase commutation in brushless DC machines,” IEEE Trans. Ind. Appl., vol.28, no.3, pp. 632-638, May/Jun. 1992.

[3] H. Tan, “Controllability analysis of torque ripple due to phase commutation in brushless DC motors,” in Proc. 5th int. conf. Elect. Mach. And Syst., Aug. 18-20, 2001, vol.2, pp. 1317-1322.

[4] Y. Murai, Y. Kawase, K. Ohashi, K. Nagatake and K. Okuyama, “Torque ripple improvement for brushless DC miniature motors,” IEEE Trans. Ind. Appl., vol.25, no.3, pp. 441-450, May/Jun. 1989.

[5] C.S. Berendsen, G. Champenois, and A. Bolopion, “Commutation strategies for brushless DC motors: Influence on instant torque,” IEEE Trans. Power Electron., vol.8, no.2, pp. 231-236, Apr.1993.

Reducing Torque Ripple of Brushless DC Motor by Varying Input Voltage

 

ABSTRACT

This paper presents the method of reducing torque ripple of brushless direct current (BLDC) motor. In the BLDC motor, the torque ripple is decided by the back-electromotive force (EMF) and current waveform. If the back-EMF is constant in the conduction region of current, the torque ripple depends on the current ripple. The period of freewheeling region in the conduction region can be acquired by circuit analysis using the Laplace transformation and the torque ripple can be also reduced by varying input voltage to reduce the current ripple. The suggested method to reduce the torque ripple is confirmed by the dynamic simulation with the parameters of 500W BLDC motor.

KEYWORDS

  1. BLDC motor
  2. Current ripple
  3. Torque ripple
  4. Varying input voltage

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. PWM inverter and equivalent circuit of BLDC motor

EXPECTED SIMULATION RESULTS

Fig. 2. Back-EMF of 500 W BLDC motor at 6660 rpm.

Fig. 3. Current waveform of 500 W BLDC motor at 6660 rpm. (a) Experimental data. (b) Simulation data.

Fig. 4. Current and torque waveform in simulation. (a) Constant input voltage.

(b) Various input voltage..

 

CONCLUSION

This paper presents the method of reducing torque ripple of the BLDC motor by varying the input voltage after circuit analysis using the Laplace transformation. In the simulation confirmed by experiment, the torque ripple is reduced to 10%. The 500WBLDC motor used for simulation and experiment dose not have a trapezoidal back-EMF waveform but a sinusoidal back-EMF waveform. So the torque ripple is not reduced conspicuously, although the current ripple is reduced conspicuously, and produced torque ripple waveform is similar to the back-EMF waveform of 500 W BLDC motor.

REFERENCES

[1] J.-G. Lee, C.-S. Park, J.-J. Lee, G. H. Lee, H.-I. Cho, and J.-P. Hong, “Characteristic analysis of brushless motor condering drive type,” KIEE, pp. 589–591, Jul. 2002.

[2] T.-H. Kim and M. Ehsani, “Sensorless control of the BLDC motor from near-zero to high speeds,” IEEE Power Electron., vol. 19, no. 5, pp. 1635–1645, Nov. 2004.

[3] J. R. Hendershot Jr. and T. Miller, “Design of brushless permanent magnet motor,” in Oxford Magna Physics, 1st ed., 1994.

[4] P. Pillay and R. Krishnan, “Modeling, simulation, and analysis a permanent magnet brushless dc motor drive,” in Conf. Rec. 1987 IEEE IAS Annu. Meeting, San Diego, CA, Oct. 1–5, 1989, pp. 7–14.

[5] R. Carlson, M. Lajoie-Mazenc, and J. C. dos Fagundes, “Analsys of torque ripple due to phase commutation in brushless dc machines,” IEEE Trans. Ind. Appl., vol. 28, no. 3, pp. 632–638.

Compensation of torque ripple in high performance BLDC motor drives

 

ABSTRACT:

Brushless DC motor drives (BLDC) are finding expanded use in high performance applications where torque smoothness is essential. The nature of the square-wave current excitation waveforms in BLDC motor drives permits some important system simplifications compared to sinusoidal permanent magnet AC (PMAC) machines. However, it is the simplicity of the BLDC motor drive that is responsible for causing an additional source of ripple torque commonly known as commutation torque to develop. In this paper, a compensation technique for reducing the commutation torque ripple is proposed. With the experimental results, the proposed method demonstrates the effectiveness for a control system using the BLDC motors that requires high speed and accuracy.

KEYWORDS:

  1. Brushless DC motor drives
  2. Commutation
  3. Torque ripple
  4. Trapezoidal back EMF

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. The block diagram of the speed controller.

EXPECTED SIMULATION RESULTS:

Fig. 2. Experimental result in low-speed range (without compensation).

Fig. 3. Experimental result in low-speed range (with compensation).

Fig. 4. Experimental result in the high-speed range (without compensation).

Fig. 5. Experimental result in the high-speed range (with compensation).

Fig. 6. Experimental result in the high-speed range (with compensation).

Fig. 7. Sine wave response for the proposed speed controller.

CONCLUSION:

This paper has proposed a compensation technique for reducing the commutation torque ripple in high-performance BLDC motor drives. The idea is to equalize the mismatched times of two commutated phase currents during the commutation intervals. In low-speed operation, a method to slow down the rising time of the on-going phase current can be a desirable technique. In high-speed operation, a method to slow down the falling time of the off-going phase current becomes a desirable strategy. However, it is not easy to implement the proposed strategies by using cost-effective one-chip microprocessors because it is needed to calculate the commutation time intervals within the sampling period in low and high speed operation. Instead of calculating the commutation time intervals, two dimensional lookup tables that describe the relation of the commutation time interval and the motor parameters such as the back EMF and the initial motor current, are used. For the experiments, a 16-bit microprocessor was used for the controller. Additionally a CPLD (1600 gates) was used to generate gate signals of the inverter and the commutation time signals. To verify the feasibility of the propose method, it is applied to the spindle motor drive control for the industrial sewing machines. The effects of torque ripple are particularly undesirable in the industrial sewing machines. They lead to speed oscillations which cause deterioration in the performance. In addition, the torque ripple may excite resonances in the mechanical portion of the drive system, produce acoustic noise. With the experimental results, the proposed method demonstrates the effectiveness for a high-performance control system using the BLDC motors that requires high speed and accuracy.

REFERENCES:

 

Berendesen, C., Champenois, G., & Bolopion, A. (1993). Commutation strategies for brushless DC motor: influence on instant torque. IEEE Transactions on Power Electronics, 8(2), 231–236. Carlson, R., Lajoie-Mazenc, M., & Fagundes, J. C. S. (1992). Analysis of torque ripple due to phase commutation in brushless DC machines. IEEE Transactions on Industry Applications, 28(3), 632–638.

Chung, K., Zhu, Y., Lee, I., Lee, K., & Cho, Y. (2007). Simulation of the reduction of force ripples of the permanent magnet linear synchronous motor. Journal of E. E. T, 2(2), 208–215. Holtz, J., & Springob, L. (1996). Identification and compensation of torque ripple in high-precision permanent magnet motor drives. IEEE Transactions on Industrial Electronics, 43(2), 309–320.

Jahns, T. M., & Soong, W. L. (1996). Pulsating torque minimization techniques for permanent magnet AC motor drives—a review. IEEE Transactions on Industrial Electronics, 43(2), 321–330.

A Torque Ripple Suppression Circuit for Brushless DC Motors based on Power DC/DC Converters

 

ABSTRACT:

This paper demonstrates a method of using a DC-DC boost conversion circuit to suppress the commutation torque ripple of a brushless DC (BLDC) motor with rectangular flux distribution. The commutation torque of a BLDC motor is depending on the commutation transient line current. To calculate the line current accurately, the phase resistance is taken into account, and the phase currents rising and falling speed are compared. Furthermore, it is proved that the line current will maintain constant if the DC voltage is lifted in the commutation period. The desired voltage is even higher than the supplied DC link voltage, if the back EMF is higher than two fifths of the input DC voltage. A super-lift Luo-converter is employed to increase the input voltage. The required waveform of the transient voltage is accomplished by changing the parameters of the power DC/DC converter based on the mathematical modeling for the proposed circuit. And the torque ripple is under control. The control stratagem for the torque ripple suppression is described in the paper and its reliability is testified by the simulation and experiment results.

KEYWORDS:

  1. Brushless DC (BLDC) motor
  2. Torque ripple
  3. Super-lift Luo-converter
  4. Mathematical modeling
  5. Commutation current

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. A typical BLDC drive system.

EXPECTED SIMULATION RESULTS:

Fig. 2. Simulated DC link current of the proposed BLDC drive system.

Fig. 3. Measured DC link current of a typical BLDC drive system.

Fig. 4. Measured DC link current of the proposed BLDC drive system.

REFERENCES:

[1] R Carlson, M Lajoie-Mazenc, J Fagundes. Analysis of torque ripple due to phase commutation in Brushless DC machines[J]. IEEE Trans. Ind.Applicat., 1992, 28: 632-638.

[2] Y Murai, Y Kawase, K Ohashi, et al. Torque ripple improvements for brushless DC miniature motors[J]. IEEE Transactions on Industry Applications, 1989, 25(3): 441-450.

[3] Liu Yong, Zhu Z Q and David H, “Commutation-Torque-Ripple Minimization in Direct-Torque-Controlled PM Brushless DC Drives,” IEEE Trans on Industry Applications, vol.43, pp.1012-1021, July 2007.

[4] Zhang Xiaofeng and Lu Zhengyu, “A New BLDC Motor Drives Method Based on BUCK Converter for Torque Ripple Reduction,” IEEE 5th International Conf. on Power Electronics and Motion Control, vol. 2, pp. 1-4, August 2006.

[5] Ki-Yong Nam, Woo-Taik Lee, Choon-Man Lee and Jung-Pyo Hong, “Reducing torque ripple of brushless DC motor by varying input voltage,” IEEE Trans. on Magnetics, vol.42, pp. 1307 – 1310, April 2006.

A New BLDC Motor Drives Method Based on BUCK Converter for Torque Ripple Reduction

 

ABSTRACT:

This paper presents a comprehensive analysis on torque ripples of brushless dc motor drives in conduction region and commutation region. A novel method for reducing the torque ripple in brushless dc motors with a single current sensor has been proposed by adding BUCK converter in the front of 3-phase inverter.In such drives, torque ripple suppression technique is theoretically effective in commutation region as well as conduction region. Effectiveness and feasibility of the proposed control method is verified through experiments.

KEYWORDS:

  1. Brushless dc motor
  2. Torque ripple
  3. Conduction region
  4. Commutation region

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

 

Fig1. The new proposed circuit configuration

 EXPECTED SIMULATION RESULTS:

Fig.2. The 2-phase current-waveforms of conventional modulation mode

Fig.3. The 2-phase current-waveforms of new proposed modulation mode

 

Fig.4.The commutation current-waveforms of conventional modulation mode

Fig.5.The commutation current-waveforms of new proposed modulation mode

 CONCLUSION:

In this paper,a new torque ripple reduction method based on buck converter has been proposed for brushless dc motor drives using a single dc current sensor. In such control method, the dc-link current sensor can give correct information corresponding to the motor phase currents to eliminate torque ripples in conduction region. Meanwhile, torque ripples have been attenuated effectively during commutation region. Subsequently effectiveness and feasibility of the proposed control method are verified through experiments.

REFERENCES:

[1] Joong-Ho Song and Ick Choy, “Commutation torque ripple reduction in brushless DC motor drives using a single DC current sensor,”IEEE Trans. on Power Electronics,vol. 19, No.2 ,pp.312-319,March 2004.

[2] Byoung-Hee Kang,Choel-Ju Kim,Hyung-Su Mok and Gyu-Ha Choe, “Analysis of torque ripple in BLDC motor with commutation time,”Proceedings of IEEE,vol.2,pp.1044-1048, June 2001.

[3] Carlson R,Lajoie-Mazenc M and Fagundes J.C.d.S, “Analysis of torque ripple due to phase communtation in brushless DC machines,”IEEE Trans. on Industry Applications,vol.28,no.3, pp.632-638,May-June 1992.

[4] Luk P.C.K and Lee C.K, “Efficient modeling for a brushless DC motor drive,”International Conference on Industrial Electronics,Control and Instrumentation,vol.1,pp.188-191, September 1994.

[5] Lei Hao,Toliyat,H.A, “BLDC motor full speed range operation including the flux-weakening region,”IEEE-IAS Annual Meeting,vol.1,pp.618-624, Octorber 2003.

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

 

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.

Commutation Torque Ripple Reduction in BLDC Motor Using Modified SEPIC Converter and Three-level NPC Inverter

ABSTRACT:

 This paper presents a new power converter topology to suppress the torque ripple due to the phase current commutation of a brushless DC motor (BLDCM) drive system. A combination of a 3-level diode clamped multilevel inverter (3-level DCMLI), a modified single-ended primary-inductor converter (SEPIC), and a dc-bus voltage selector circuit are employed in the proposed torque ripple suppression circuit. For efficient suppression of torque pulsation, the dc-bus voltage selector circuit is used to apply the regulated dc-bus voltage from the modified SEPIC converter during the commutation interval. In order to further mitigate the torque ripple pulsation, the 3-level DCMLI is used in the proposed circuit. Finally, simulation and experimental results show that the proposed topology is an attractive option to reduce the commutation torque ripple significantly at low and high speed applications.

KEYWORDS:

  1. Brushless direct current motor (BLDCM)
  2. Dc-bus voltage control
  3. Modified single-ended primary-inductor converter
  4. 3-level diode clamped multilevel inverter (3-level DCMLI)
  5. Torque ripple

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Proposed converter topology with a dc-bus voltage selector circuit for BLDCM

 EXPECTED SIMULATION RESULTS:

Fig. 2. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 3. Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 4. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and switch a selection circuit. (d) BLDCM fed by proposed topology.

Fig. 5. Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 6. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 7. Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

CONCLUSION:

In this paper, a commutation torque ripple reduction circuit has been proposed using 3-level DCMLI with modified SEPIC converter and a dc-bus voltage selector circuit. A laboratory-built drive system has been tested to verify the proposed converter topology. The suggested dc-bus voltage control strategy is more effective in torque ripple reduction in the commutation interval. The proposed topology accomplishes the successful reduction of torque ripple in the commutation period and experimental results are presented to compare the performance of the proposed control technique with the conventional 2-level inverter, 3-level DCMLI, 2-level inverter with SEPIC converter and the switch selection circuit-fed BLDCM. In order to obtain significant torque ripple suppression, quietness and higher efficiency, 3-level DCMLI with modified SEPIC converter and the voltage selector circuit is a most suitable choice to obtain high-performance operation of BLDCM. The proposed topology may be used for the torque ripple suppression of BLDCM with the very low stator winding inductance.

REFERENCES:

[1] N. Milivojevic, M. Krishnamurthy, Y. Gurkaynak, A. Sathyan, Y.-J. Lee, and A. Emadi, “Stability analysis of FPGA-based control of brushless DC motors and generators using digital PWM technique,” IEEE Trans. Ind. Electron., vol. 59, no. 1, pp. 343–351, Jan. 2012.

[2] X. Huang, A. Goodman, C. Gerada, Y. Fang, and Q. Lu, “A single sided matrix converter drive for a brushless dc motor in aerospace applications,” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3542–3552, Sep. 2012.

[3] X. Huang, A. Goodman, C. Gerada, Y. Fang, and Q. Lu, “Design of a five-phase brushless DC motor for a safety critical aerospace application,” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3532-3541, Sep. 2012.

[4] J.-G. Lee, C.-S. Park, J.-J. Lee, G. H. Lee, H.-I. Cho, and J.-P. Hong, “Characteristic analysis of brushless motor condering drive type,” KIEE, pp. 589-591, Jul. 2002.

[5] T. H. Kim and M. Ehsani, “Sensorless control of BLDC motors from near-zero to high speeds,” IEEE Trans. Power Electron., vol. 19, no. 6, pp. 1635–1645, Nov. 2004.

 

Direct Torque Control of Induction Motors with Fuzzy Minimization Torque Ripple

ABSTRACT
Direct torque control (DTC) is a new method of induction motor control. The key issue of the DTC is the strategy of selecting proper stator voltage vectors to force stator flux and developed torque within a prescribed band. Due to the nature of hysteresis control adopted in DTC, there is no difference in control action between a larger torque error and a small one. It is better to divide the torque error into different intervals and give different control voltages for each of them. To deal with this issue a fuzzy controller has been introduced. But, because the number of rules is too high some problems arise and the speed of fuzzy reasoning will be affected. In this paper, a comparison between a new fuzzy direct-torque control (DTFC) with space vector modulation (SVM) is made. The principle and a tuning procedure of the fuzzy direct torque control scheme are discussed. The simulation results, which illustrate the performance of the proposed control scheme in comparison with the fuzzy hysteresis connected of DTC scheme are given.
KEYWORDS
1. Induction machine
2. Direct torque control
3. Fuzzy logic
4. Space vector modulation
SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. A novel direct torque control scheme for ac motor drives (DTC) with fuzzy hysteresis and space vector modulation

EXPECTED SIMULATED RESULTS:


Fig.2. response of trajectory of flux, electromagnetic torque and stator current for scheme of simulation results of fuzzy-hysteresis regulators connected

Fig. 3. response of trajectory of flux, electromagnetic torque and stator current for scheme of DTC- fuzzy hysteresis with SVM

CONCLUSION:
In this paper, a fuzzy direct torque control with space vector modulation is analyzed in comparison to fuzzy hysteresis connected of DTC. The results obtained by numerical simulation are given. In short, the advantages of proposed fuzzy direct torque control using space vector modulation technique in comparison with a fuzzy hysteresis of DTC are the following:
– Reduced torque and flux distortion;
– Constant switching frequency thanks to apply SVM;
– Fast torque response because of the use of fuzzy controller;
– Lower sampling time;
– No problems during Low-speed operation;
– No current and torque distortion caused by sector changes.
REFERENCES:
[1] Casadei, D., serra, G., Tani, A, «Performance analysis of a DTC control scheme for induction motor in the low speed range», in proceeding of EPE, (1997), p.3.700-3.704, Trondheim.
[2] Depenbrok. M, «Direct self-control (DSC) of inverter fed induction machine», In: IEEE Trans. On PE (1988), Vol. PE-3, No4, October 1988, p 420-429.
[3] A. Cataliotti, G. Poma: “A Fuzzy approach for easy and robust control of an induction motor”. EPE 97, pp 2.421-2.425, 1997.
[4] J. R G Schonfield,”Direct torque control-DTC”, ABB Industrial Systems Ltd.
[5] Ned Gulley, J.-S. Roger Jang: Fuzzy Logic Toolbox for Use With Matlab”. The Math Works inc, Natick, Mass, 1996.