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.

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.

Approach for torque ripple reduction for brushless DC motor based on three-level neutral-point-clamped inverter with DC–DC converter

ABSTRACT:

This study proposes a novel topology for reducing commutation torque ripple in a brushless DC motor (BLDCM) drive system using a three-level neutral-point-clamped (NPC) inverter combined with single-ended primary-inductor converter (SEPIC) converters. In the BLDCM, current ripples arise because of the influence of stator winding inductance, which generates torque ripples. The torque ripple that is generated in the commutation period prevents the use of BLDCM in high-precision servo drive systems. In this study, two-stage converters are proposed to reduce the torque ripple. The first stage consists of two SEPIC converters to obtain the desired commutation voltage according to motor speed. A dc-link voltage selection circuit is combined with the SEPIC converters to apply the optimised voltage during the commutation interval. To reduce the torque ripple further, a three-level NPC inverter is used to apply a half dc-link voltage across the motor winding and this effectively reduces the torque ripple. Experimental results show that the proposed topology is able to reduce commutation torque ripple significantly under both low-speed and high-speed operation.

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1 Simulation block diagram of the proposed topology with the BLDCM

EXPECTED SIMULATION RESULTS:

Fig. 2 Simulation results of phase current and torque a Phase current waveform of the conventional control at 3000 rpm and 0.825 Nm b Torque waveform of the conventional control at 3000 rpm and 0.825 Nm c Phase current waveform of the proposed topology at 3000 rpm and 0.825 Nm d Torque waveform of the proposed topology at 3000 rpm and 0.825 Nm

Fig. 3 Simulation results of phase current and torque a Phase current waveform of the conventional control at 6000 rpm and 0.825 Nm b Torque waveform of the conventional control at 6000 rpm and 0.825 Nm c Phase current waveform of the proposed topology at 6000 rpm and 0.825 Nm d Torque waveform of the proposed topology at 6000 rpm and 0.825 Nm

CONCLUSION:

In this paper, a novel topology has been proposed to suppress the commutation torque ripple of a BLDCM using two SEPIC converters and a MOSFET-based three-level NPC inverter. The SEPIC converters are used to adjust the dc-link voltage and thus to suppress the torque ripple during the commutation period. To verify the feasibility of the proposed topology, simulation and experiments were conducted using low and high speeds. The results of this paper have demonstrated that the proposed topology can effectively reduce the commutation torque ripple. Therefore, the proposed solution has high potential for vehicular and aerospace applications in which torque ripple minimization is of great importance.

REFERENCES:

1 Lee, J.G., Park, C.S., Lee, J.J., Lee, G.H., Cho, H.O., Hong, J.P.: ‘Characteristic analysis of brushless motor considering drive type’, Trans. Korean Inst. Electr. Eng., 2002, 5, pp. 589–591

2 Kim, T.H., Ehsani, M.: ‘Sensorless control of the BLDC motor from near-zero to high speeds’, IEEE Power Electron., 2004, 19, (6), pp. 1635–1645

3 Viswanathan, V., Jeevananthan, S.: ‘A novel space-vector current control method for commutation torque ripple reduction of brushless DC motor drive’, Arab Sci. J. Eng., 2013, 38, (10), pp. 1773–2784

4 Miller, T.J.E.: ‘Brushless PM and reluctance motor drives’ (Clarendon press, New York, 1989)

5 Ilhwan, K., Nobuaki, N., Sungsoo, K., Chanwon, P., Chansu, Yu.: ‘Compensation of torque ripple in high performance BLDC motor drives’, Control Eng. Pract., 2010, 18, pp. 1166–1172

An Adjustable-Speed PFC Bridgeless Buck–Boost Converter-Fed BLDC Motor Drive

ABSTRACT:

This paper presents a power factor corrected (PFC) bridgeless (BL) buck–boost converter-fed brushless direct current (BLDC) motor drive as a cost-effective solution for low-power applications. An approach of speed control of the BLDC motor by controlling the dc link voltage of the voltage source inverter (VSI) is used with a single voltage sensor. This facilitates the operation of VSI at fundamental frequency switching by using the electronic commutation of the BLDC motor which offers reduced switching losses. A BL configuration of the buck–boost converter is proposed which offers the elimination of the diode bridge rectifier, thus reducing the conduction losses associated with it. A PFC BL buck–boost converter is designed to operate in discontinuous inductor current mode (DICM) to provide an inherent PFC at ac mains. The performance of the proposed drive is evaluated over a wide range of speed control and varying supply voltages (universal ac mains at 90–265 V) with improved power quality at ac mains. The obtained power quality indices are within the acceptable limits of international power quality standards such as the IEC 61000-3-2. The performance of the proposed drive is simulated in MATLAB/Simulink environment, and the obtained results are validated experimentally on a developed prototype of the drive.

KEYWORDS:

1.      Bridgeless (BL) buck–boost converter

2.      Brushless direct current (BLDC) motor

3.       Discontinuous inductor current mode (DICM)

4.       Power factor corrected (PFC)

5.      Power quality

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Proposed BLDC motor drive with front-end BL buck–boost converter.

EXPECTED SIMULATION RESULTS:

Fig. 2. Steady-state performance of the proposed BLDC motor drive at rated conditions.

Fig. 3. Harmonic spectra of supply current at rated supply voltage and rated

loading on BLDC motor for a dc link voltage of (a) 200 V and (b) 50 V.

Fig. 4. Dynamic performance of proposed BLDC motor drive during (a) starting, (b) speed control, and (c) supply voltage variation at rated conditions.

Fig. 5. Harmonic spectra of supply current at rated loading on BLDC motor

with dc link voltage as 200 V and supply voltage as (a) 90 V and (b) 270 V.

Fig. 6. Steady-state performance of the proposed BLDC motor drive at rated

conditions with dc link voltage as (a) 200 V and (b) 50 V.

CONCLUSION:

A PFC BL buck–boost converter-based VSI-fed BLDC motor drive has been proposed targeting low-power applications. A new method of speed control has been utilized by controlling the voltage at dc bus and operating the VSI at fundamental frequency for the electronic commutation of the BLDC motor for reducing the switching losses in VSI. The front-end BL buck–boost converter has been operated in DICM for achieving an inherent power factor correction at ac mains. A satisfactory performance has been achieved for speed control and supply voltage variation with power quality indices within the acceptable limits of IEC 61000-3-2. Moreover, voltage and current stresses on the PFC switch have been evaluated for determining the practical application of the proposed scheme. Finally, an experimental prototype of the proposed drive has been developed to validate the performance of the proposed BLDC motor drive under speed control with improved power quality at ac mains. The proposed scheme has shown satisfactory performance, and it is a recommended solution applicable to low-power BLDC motor drives.

REFERENCES:

[1] C. L. Xia, Permanent Magnet Brushless DC Motor Drives and Controls. Hoboken, NJ, USA: Wiley, 2012.

[2] J. Moreno, M. E. Ortuzar, and J. W. Dixon, “Energy-management system for a hybrid electric vehicle, using ultracapacitors and neural networks,” IEEE Trans. Ind. Electron., vol. 53, no. 2, pp. 614–623, Apr. 2006.

[3] Y. Chen, C. Chiu, Y. Jhang, Z. Tang, and R. Liang, “A driver for the singlephase brushless dc fan motor with hybrid winding structure,” IEEE Trans. Ind. Electron., vol. 60, no. 10, pp. 4369–4375, Oct. 2013.

[4] 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.

[5] H. A. Toliyat and S. Campbell, DSP-Based Electromechanical Motion Control. Boca Raton, FL, USA: CRC Press, 2004.

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.