assessing pulse-width modulation techniques for brushless dc motor drives

Department of Electrical Engineering Southern Taiwan University


Robot and Servo Drive Lab.

Assessing pulse-width modulation techniques for brushless dc motor

drives

Student: Tai-Rong Lai

Professor: Ming-Shyan Wang

112/04/20

BY YEN-SHIN LAI & YONG-KAI LINIEEE INDUSTRY APPLICATIONS MAGAZINE ∙SEPT j OCT 2008 ∙

WWW. IEEE.ORG/IAS pp34-44.



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Outline Abstract

PWM techniques for BLDCM Drive

Driver Circuit

Reversal dc-Link Current

Circulating Current of Floating Phase

Back EMF Detection

Assessment of PWM Techniques—Theoretical Analysis and Experimental Confirmation

Conclusions

References

112/04/20

Robot and Servo Drive Lab.2



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Abstract

The aim of this article is to assess the PWM techniques for BLDCM drives.

• Driver circuit

• Reversal dc-link current

• Circulating current of floating phase

• Back-EMF



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Driver Circuit

Photocoupler driver

Isolated transformer driver

Bootstrap driver



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Photocoupler driver



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Isolated transformer driver



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Bootstrap driver



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Driver Circuit



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Reversal dc-Link Current

CH1:chopper CH2:Vu CH3:Iu CH4:Idc



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Reversal dc-link current, phase U



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Back EMF Detection

Vp:denotes the terminal voltage for the phase connected to the positive dc-link rail during PWM control period.

Vn indicates the terminal voltage for the phase connected to the negative dc-link rail.

Vo is the terminal voltage for the floating phase.



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Back EMF Detection



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Assessment of PWM Techniques—Theoretical Analysis and Experimental Confirmation

Block diagram of the sensorless experimental system



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Motor specifications

Number of poles=8 Rated power=70W V dc= 24 V Rated speed=2,500 rpm



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CH1: high-side control, CH2: low-side control, CH3: terminal voltageCH4: phase current, duty = 20%.



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CH1: high-side control, CH2: low-side control, CH3: terminal voltageCH4: phase current, duty = 80%.



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CH1: high-side control, CH2: low-side control, CH3: terminal voltageCH4: dc-link current, duty = 20%.



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CH1: high-side control, CH2: low-side control, CH3: terminal voltageCH4: dc-link current, duty = 80%.



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CH1: terminal voltageCH2: phase current, duty = 80%.No load



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Conclusions

The aim of this article is to assess the special features of five PWM techniques for BLDCM control. As shown here, the indexes include reversal dc-link current, circulating current, driver circuit, and back-EMF detection. Theoretical analysis is presented and followed by the experimental results. An inverter-controlled BLDCM drive without using any hall sensor and current sensor is set up. Experimental results fully support the analysis. These results provide the whole picture for applications reference.



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References

[1] Seiko Epson Corp., ‘‘Brushless dc motor without position sensor and its controller,’’ E.P. Patent 0 553 354 B1, 1993.

[2] Tokyo Shibaura Electric Co., ‘‘Inverter and air conditioner controlled by the same,’’ U.S. Patent 5 486 743, 1996.

[3] ST Microelectronics, ‘‘Control of a brushless motor,’’ U.S. Patent 5 859 520, 1999.

[4] J. Shao, D. Nolan, M. Teissier, and D. Swanson, ‘‘A novel microcontroller-based sensorless brushless dc (BLDC) motor drive for automotive fuel pumps,’’ IEEE Trans. Ind. Appl., vol. 39, pp. 1734–1740, Nov./Dec. 2003.

[5] G. J. Su and J. W. McKeever, ‘‘Low-cost sensorless control of brushless dc motors with improved speed range,’’ IEEE Trans. Ind. Applicat., vol. 19, pp. 296–303, Mar. 2003.

[6] R. C. Becerra, T. M. Jahns, and M. Ehsani, ‘‘Four-quadrant sensorless brushless ECM drive,’’ in Proc. 6th Annu. Applied Power Electronics Conf. Exposition, Mar. 1991, pp. 202–209.



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References

[7] S. Ogasawara and H. Akagi, ‘‘An approach to position sensorless drive for brushless dc motors,’’ IEEE Trans. Ind. Applicat., vol. 27, pp. 928–933, Sept./Oct. 1991.

[8] Y. S. Lai, F. S. Shyu, and Y. H. Chang, ‘‘Novel loss reduction pulsewidth modulation technique for brushless dc motor drives fed by MOSFET inverter,’’ IEEE Trans. Power Electron., vol. 19, no. 6, pp. 1646–1656, 2004.

[9] Y. S. Lai, F. S. Shyu, and Y. H. Chang, ‘‘Novel pulse-width modulation technique with loss reduction for small power brushless dc motor drives,’’ in Conf. Rec. IEEE IAS Annu. Meeting, 2002, pp. 2057–2064.

[10] Tokyo Shibaura Electric Co., ‘‘Drive control apparatus for brushless dc motor and driving method therefore,’’ U.S. Patent 5 491 393, 1996.

[11] Y. S. Lai, F. S. Shyu, and Y. K. Lin, ‘‘Novel PWM technique without causing reversal dc-link current for brushless dc motor drives with bootstrap driver,’’ in Conf. Rec. IEEE IAS Annu. Meeting, 2005, pp. 2182–2188.

[12] Y. S. Lai and Y. K. Lin, ‘‘A unified approach to back-EMF detection for brushless dc motor drives without current and Hall sensor,’’ in Proc. IEEE IECON, Nov. 2006, pp. 1293–1298.



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References

[13] L6385: High-Voltage High and Low Side Driver, ST Microelectronics Datasheet, USA, 1999.

[14] J. T. Strydom, M. A. De Rooij, and J. D. Van Wyk, ‘‘A comparison of fundamental gate-driver topologies for high frequency applications,’’ in Proc. IEEE APEC, 2004, vol. 2. pp. 1045–1052.

[15] S. D. Sudhoff and P. C. Krause, ‘‘Operating modes of the brushless dc motor with a 120 inverter,’’ IEEE Trans. Energy Conversion, vol. 5, no. 3, pp. 558–564, 1990.



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Robot and Servo Drive Lab.30

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assessing pulse-width modulation techniques for brushless dc motor drives

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