Assessing pulse-width modulation techniques for brushless dc motor drives

1. Assessing pulse-width modulation techniques for brushless dc motor drives BY YEN-SHIN LAI & YONG-KAI LINIEEE INDUSTRY APPLICATIONS MAGAZINE ∙SEPT j OCT 2008 ∙ WWW. IEEE.ORG/IAS pp34-44. Student: Tai-Rong Lai Professor: Ming-Shyan Wang

2. 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 2 Robot and Servo Drive Lab.

3. 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 Abstract

4. PWM techniques for BLDCM Drive

5. PWM techniques for BLDCM Drive

6. PWM techniques for BLDCM Drive

7. Photocoupler driver Isolated transformer driver Bootstrap driver Driver Circuit

8. Photocoupler driver

9. Isolated transformer driver

10. Bootstrap driver

11. Driver Circuit

12. Reversal dc-Link Current CH1:chopper CH2:Vu CH3:Iu CH4:Idc

13. Reversal dc-link current, phase U

14. Circulating Current of Floating Phase

15. Circulating Current of Floating Phase

16. 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. Back EMF Detection

17. Back EMF Detection

18. Assessment of PWM Techniques—Theoretical Analysis and Experimental Confirmation Block diagram of the sensorless experimental system

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

20. CH1: high-side control, CH2: low-side control, CH3: terminal voltage CH4: phase current, duty = 20%.

21. CH1: high-side control, CH2: low-side control, CH3: terminal voltage CH4: phase current, duty = 80%.

22. CH1: high-side control, CH2: low-side control, CH3: terminal voltage CH4: dc-link current, duty = 20%.

23. CH1: high-side control, CH2: low-side control, CH3: terminal voltage CH4: dc-link current, duty = 80%.

24. CH1: terminal voltage CH2: phase current, duty = 80%. No load

26. 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. Conclusions

27. [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. References

28. [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. References

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30. Thanks for your listening ！ 30 Robot and Servo Drive Lab.