1. Adviser：Ming-Shyan Wang Student：Hung-Lin Huang
Dynamic Performance of Brushless DC Motors With Unbalanced Hall Sensors
IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 23, NO. 3, page752~763 SEPTEMBER 2008
Nikolay Samoylenko, Student Member, IEEE, Qiang Han, Student Member, IEEE, and Juri Jatskevich, Senior Member, IEEE
Adviser：Ming-Shyan Wang
Student：Hung-Lin Huang
2018/9/19

2. Robot and Servo Drive Lab.
Outline
Abstract
Introduction
Permanent Magnet BLDC Machine Model
Filtering Hall Signals
Reference Switching Time
Implementation and Case Studies
Discussion
Conclusion
Appendix
References
2018/9/19
Robot and Servo Drive Lab.

3. Robot and Servo Drive Lab.
Abstract
The Hall sensors in the BLDCM are ideally placed 120 electrical degrees apart. But most of the BLDC motor's hall sensors are unbalanced lead to unbalanced operation of the inverter and motor phases.
The misplaced Hall sensors which increases the low-frequency harmonics in torque ripple and degrades the overall drive performance.
This paper also presents some average-filtering methods that can be applied to the original Hall-sensor signals to reduce the effect of unbalanced placement during transient and steady-state.
2018/9/19
Robot and Servo Drive Lab.

4. Robot and Servo Drive Lab.
Introduction(1/2)
This paper describes the phenomenon of unbalanced placement of Hall-sensors. The nonideal condition would reduce the electromechanical performance.
2018/9/19
Robot and Servo Drive Lab.

5. Robot and Servo Drive Lab.
Introduction(2/2)
We propose a simple but very effective and practical filtering technique to improve the overall performance of a BLDC motor-drive system with significant unbalance in Hall-sensor positioning.
This paper generalizes the approach of filtering the Hall-sensor signals and provides the experimental results.
The methodology does not require any additional circuitry or hardware. This solution can be implemented motor controller, and therefore, may be useful for many applications.
2018/9/19
Robot and Servo Drive Lab.

6. BLDC drive system with filtering of Hall-sensor signals
2018/9/19
Robot and Servo Drive Lab.

7. Robot and Servo Drive Lab.
BLDC Machine Model
H{1,2,3}
 actual Hall sensors
H{1,2,3}’
 ideal Hall sensors
ϕA,ϕB,ϕC
 error degrees
2018/9/19
Robot and Servo Drive Lab.

8. Robot and Servo Drive Lab.
BLDC Machine Model
Stator voltage equation
Stator flux linkages
2018/9/19
Robot and Servo Drive Lab.

9. Robot and Servo Drive Lab.
BLDC Machine Model
Electromagnetic torque
2018/9/19
Robot and Servo Drive Lab.

10. Robot and Servo Drive Lab.
BLDC Machine Model
Stator phase currents.
Speed = 2458 rpm
Steady-state operating condition
2018/9/19
Robot and Servo Drive Lab.

11. Robot and Servo Drive Lab.
BLDC Machine Model
Electromagnetic torque waveforms.
2018/9/19
Robot and Servo Drive Lab.

12. Robot and Servo Drive Lab.
BLDC Machine Model
Electromagnetic torque harmonic content.
2018/9/19
Robot and Servo Drive Lab.

13. Filtering Hall Signals
180°
60°
2018/9/19
Robot and Servo Drive Lab.

14. Filtering Hall Signals
2018/9/19
Robot and Servo Drive Lab.

15. Filtering Hall Signals
A. Basic Average Filters
suppressed and radians/sample
1) six-step filter
2) three-step filter
2018/9/19
Robot and Servo Drive Lab.

16. Filtering Hall Signals
B. Extrapolating Filters
(linear extrapolation)
2018/9/19
Robot and Servo Drive Lab.

17. Filtering Hall Signals
B. Extrapolating Filters
(quadratic extrapolation)
2018/9/19
Robot and Servo Drive Lab.

18. Filtering Hall Signals
C. Performance of Filters (Magnitude and phase responses of different filters)
2018/9/19
Robot and Servo Drive Lab.

19. Filtering Hall Signals
C. Performance of Filters (Response of different filters to a ramp increase in speed)
2018/9/19
Robot and Servo Drive Lab.

20. Reference Switching Time
The actual timing for commutating as follows:
is the reference switching time
may be the
2018/9/19
Robot and Servo Drive Lab.

21. Reference Switching Time
The reference switching time
“*” Phase A, B, or C
2018/9/19
Robot and Servo Drive Lab.

22. Implementation and Case Studies
Microcontroller：PIC18F2331
“counter”：number of Hall-sensor transitions
“threshold”：Filter order +1
filter disable
filter enable
2018/9/19
Robot and Servo Drive Lab.

23. Implementation and Case Studies
A. Startup Transient
2018/9/19
Robot and Servo Drive Lab.

24. Implementation and Case Studies
B. Load-Step Transient
2018/9/19
Robot and Servo Drive Lab.

25. Implementation and Case Studies
C. Voltage-Step Transient
No loads
steps up from 20V to 35V
Using three- and six-step
averaging filters
2018/9/19
Robot and Servo Drive Lab.

26. Implementation and Case Studies
C. Voltage-Step Transient
No loads
steps up from 20V to 35V
Using extrapolating averaging
filters
2018/9/19
Robot and Servo Drive Lab.

27. Implementation and Case Studies
C. Voltage-Step Transient
Basic moving-average filters Extrapolating filters
2018/9/19
Robot and Servo Drive Lab.

28. Robot and Servo Drive Lab.
Discussion
A. Steady-State Operation
Firing angle：
2018/9/19
Robot and Servo Drive Lab.

29. Robot and Servo Drive Lab.
Discussion
B. Transient Operation
0.105 s
2018/9/19
Robot and Servo Drive Lab.

30. Robot and Servo Drive Lab.
Conclusion
This paper presented the phenomenon from low-precision BLDC motors with unbalanced Hall-sensor.
Several filters have been proposed to improve the performance of BLDC motors.
Using extrapolating and averaging filters will be the useful method to improve the low-precision BLDC motors’ performance.
2018/9/19
Robot and Servo Drive Lab.

31. Robot and Servo Drive Lab.
Appendix
BLDC Machine Parameters:
Arrow Precision Motor Corporation, Ltd.
Model：86EMB3S98 F
Inertia：
Back EMF harmonic coefficients：
2018/9/19
Robot and Servo Drive Lab.

32. Robot and Servo Drive Lab.
References(1/2)
[1] P. C. Krause, O. Wasynczuk, and S. D. Sudhoff, Analysis of Electric Machinery and Drive Systems. Piscataway, NJ: IEEE Press, 2002.
[2] S. D. Sudhoff and P. C. Krause, “Average-value model of the brushless dc 120◦ inverter system,” IEEE Trans. Energy Convers., vol. 5, no. 3, pp. 553–557, Sep
[3] S. D. Sudhoff and P. C. Krause, “Operation modes of the brushless dc motor with a 120◦ inverter,” IEEE Trans. Energy Convers., vol. 5, no. 3, pp. 558–564, Sep
[4] P. L. Chapman, S. D. Sudhoff, and C. A. Whitcomb, “Multiple reference frame analysis of non-sinusoidal brushless dc drives,” IEEE Trans. Energy Convers., vol. 14, no. 3, pp. 440–446, Sep
[5] P. Pillay and R. Krishnan, “Modeling, simulation, and analysis of permanent-magnet motor drives. Part II. The brushless dc motor drive,” IEEE Trans. Ind. Appl., vol. 25, no. 2, pp. 274–279, Mar.–Apr
[6] W. Brown, “Brushless dc motor control made easy”, Microchip Technology,Inc., 2002 [Online]. Available:
[7] P.B.Beccue, S. D. Pekarek, B. J. Deken, andA.C.Koenig, “Compensation for asymmetries and misalignment in a Hall-effect position observer used in PMSM torque-ripple control,” IEEE Trans. Ind. Appl., vol. 43, no. 2, pp. 560–570, Mar.–Apr
[8] C. Zwyssig, S. D. Round, and J. W. Kolar, “Power electronics interface for a 100 W, rpm gas turbine portable power unit,” in Proc. IEEE Appl. Power Electron. Conf., 19–23 Mar., 2006, pp. 283–289.
[9] N. Samoylenko,Q.Han, and J. Jatskevich, “Balancing hall-effect signals in low-precision brushless dc motors,” in Proc. IEEE Appl. Power Electron. Conf., Anaheim, CA, Feb.–28 Mar.2007, pp. 606–611.
[10] N. Samoylenko, Q. Han, and J. Jatskevich, “Improving dynamic performance of low-precision brushless dc motors with unbalanced Hall sensors,” in Proc. IEEE Power Eng. Soc. General Meeting, Panel Session— Intell. Motor Control I, Tampa, FL, Jun. 24–282007, pp. 1–8.
2018/9/19
Robot and Servo Drive Lab.

33. Robot and Servo Drive Lab.
References(2/2)
[11] Simulink: Dynamic System Simulation for MATLAB, Using Simulink Version 6, The MathWorks Inc., 2006.
[12] Automated State Model Generator (ASMG), Reference Manual Version 2. West Lafayette, IN: P. C. Krause & Associates, Inc., 2003 [Online]. Available:
[13] D. Shmilovitz, “On the definition of total harmonic distortion and its effect on measurement interpretation,” IEEE Trans. Power Del., vol. 20, no. 1, pp. 526–528, Jan
[14] M. Brackley and C. Pollock, “Analysis and reduction of acoustic noise from a brushless dc drive,” IEEE Trans. Ind. Appl., vol. 36, no. 3, pp. 772–777, May/Jun
[15] A. Hartman and W. Lorimer, “Undriven vibrations in brushless dc Motors,” IEEE Trans. Magn., vol. 37, no. 2, pp. 789–792, May 2001.
[16] T. Yoon, “Magnetically induced vibration in a permanent-magnet brushless dc motor with symmetric pole-slot configuration,” IEEE Trans. Magn., vol. 41, no. 6, pp. 2173–2179, Jun
[17] J. G. Proakis and D. G. Manolakis, Digital Signal Processing. Upper Saddle River, NJ: Prentice-Hall, 1996, p. 248.
[18] PIC18F2331/2431/4331/4431 Data Sheet, 28/40/44-Pin Enhanced Flash Microcontrollers with nano Watt Technology, High Performance PWM and A/D. Microchip Technology Inc., 2003 [Online]. Available:
[19] Padmaraja Yedamale “Brushless DC Motor Control Using PIC18FXX31 MCUs,AN899,” Microchip Technology Inc [Online]. Available:
2018/9/19
Robot and Servo Drive Lab.

34. Thanks for your listening.
2018/9/19
Robot and Servo Drive Lab.