Transcript 下載/瀏覽Download

Simple position sensorless starting
method for brushless DC motor
P. Damodharan, R. Sandeep and K. Vasudevan
IET Electr. Power Appl., 2008, 2, (1), pp. 49–55
Student: 高永發
1
Outline

Abstract

Introduction

Proposed sensorless starting scheme

Simulation of the proposed sensorless starting method

Hardware implementation and test results

Discussions

Conclusion

References
2
Abstract
 Position
sensorless methods for brushless DC
motors based on back-EMF zero crossing suffer
from a starting problem since there is no backEMF at standstill.
 A simple
method by which the motor is started
from standstill up to a speed wherein sensorless
methods will be able to detect the correct
commutation instants is proposed.
 The
proposed method relies on a difference of line
voltages measured at the terminals of the motor.
3
Abstract

It is shown that this difference of line voltages
provides an amplified version of an appropriate backEMF at its zero crossings.

It is further demonstrated that this information can be
used to trigger devices so as to develop an
accelerating torque from zero speed.

This method is simple to implement and it can
reliably start the motor even with load.

The effectiveness of the proposed method is
demonstrated through simulation and hardware results.
4
Introduction

This paper proposes a simple and reliable method to detect
the back-EMF zero crossings.

It is further shown in the paper that this method can be used
to start the machine as well, once the initial rotational
movement is established. In this work, the rotor is first
brought to a known position through a prepositioning step.

Subsequent rotation of the rotor is achieved by a 120
electrical degree triggering followed by a sequential
triggering of the devices based on zero crossings of the backEMF.

Both simulation and hardware implementation results are
provided to verify the efficacy of this starting method.
5
Proposed sensorless starting scheme
dia
Van  Ra ia  La
 ean
dt
dib
Vbn  Rbib  Lb
 ebn
dt
dic
Vcn  Rc ic  Lc
 ecn
dt
Vx :The phase terminal voltage with respect to the star point of the stator
Rx : The stator resistance
Lx : The phase inductance
ix : The phase current
ex : The back EMF
2016/7/15
Southern Taiwan University of Science and Technology
6
Proposed sensorless starting scheme
Van  Ra ia  La
dia
 ean
dt
dib
Vbn  Rbib  Lb
 ebn
dt
dic
Vcn  Rc ic  Lc
 ecn
dt
2016/7/15
d (ia  ib )
Vab  R(ia  ib )  L
 ean  ebn
dt
d (ib  ic )
Vbc  R(ib  ic )  L
 ebn  ecn
dt
d (ic  ia )
Vca  R(ic  ia )  L
 ecn  ean
dt
Southern Taiwan University of Science and Technology
7
Proposed sensorless starting scheme
d (ia  ib )
Vab  R(ia  ib )  L
 ean  ebn
dt
d (ib  ic )
Vbc  R(ib  ic )  L
 ebn  ecn
dt
d (ia  2ib  ic )
Vabbc  R(ia  2ib  ic )  L
 ean  2ebn  ecn
dt
2016/7/15
Southern Taiwan University of Science and Technology
8
Proposed sensorless starting scheme
0
d (ia  2ib  ic )
Vabbc  R(ia  2ib  ic )  L
 ean  2ebn  ecn
dt
Vabbc  ean  2ebn  ecn
0
Vabbc  2ebn
2016/7/15
Southern Taiwan University of Science and Technology
9
Simulation of the proposed
sensorless starting method
10
Simulation of the proposed
sensorless starting method
11
Simulation of the proposed
sensorless starting method
12
Simulation of the proposed
sensorless starting method
13
Hardware implementation and test results
14
Hardware implementation and test results
15
Hardware implementation and test results
16
Hardware implementation and test results
17
Hardware implementation and test results
18
Discussions
19
Discussions
20
Conclusion

A simple technique to start the BLDC motor for position sensorless
schemes is proposed.

This method makes use of line-to-line voltage differences to detect
and amplify back-EMF signals so that even EMF zero crossings
caused by initial rotor rotation can be easily detected.

Subsequent device triggerings ensure acceleration and are based on
further zero crossing detections.

The motor is found to start smoothly from standstill and run up to a
speed where a sensorless scheme can take over.
21
Conclusion

Simulation and experimental results are shown, which validate the
suitability of the proposed method.

The proposed startup method has been attempted for PMAC motors
also in simulation and found to work.

However, more testing is required and presently being done.
22
References
1 Kenjo, T., and Nagamori, S.: ‘Permanent-magnet and brushless DC motors’ (Clarendon
Press, Oxford, 1985)
2 Miller, T.J.E.: ‘Brushless permanent-magnet and reluctance motor drives’ (Clarendon
Press, Oxford, 1989)
3 Iizuka, K., Uzuhashi, H., Kano, M. et al.: ‘Microcomputer control for sensorless brushless
motor’, IEEE Trans. Ind. Appl., 1985, IA-21, (4),pp. 595–601
4 Chen, H.-C., and Liaw, C.-M.: ‘Current-mode control for sensorless BDCM drive with
intelligent commutation tuning’, IEEE Trans.Power Electron., 2002, 17, (5), pp. 747–756
5 Cheng, K.-Y., and Tzou, Y.-Y.: ‘Design of a sensorless commutation IC for BLDC motors’,
IEEE Trans. Power Electron., 2003, 18, (6),pp. 1365–1375
6 Su, G.-J., and McKeever, J.W.: ‘Low-cost sensorless control of brushless DC motors with
improved speed range’, IEEE Trans.Power Electron., 2004, 19, (2), pp. 296–302
7 Jung, D.-H., and Ha, I.-J.: ‘Low-cost sensorless control of brushless DC motors using a
frequency-independent phase shifter’, IEEETrans.Power Electron., 2000, 15, (4), pp. 744–
752
8 Moreira, J.C.: ‘Indirect sensing for rotor flux position of permanent magnet AC motors
operating over a wide speed range’,IEEE Trans. Ind. Appl., 1996, 32, (6), pp. 1394–1401
9 Shao, J., Nolan, D., Teissier, M. et al.: ‘A novel microcontroller-based sensorless brushless
DC (BLDC) motor drive for automotive fuel pumps’, IEEE Trans. Ind. Appl., 2003, 39, (6),
pp. 1734–1740
10 Ogasawara, S., and Akagi, H.: ‘An approach to position sensorless drive for brushless DC
motors’, IEEE Trans. Ind. Appl., 1991, 27,(5), pp. 928–933
23
References
11 Kim, T.-H., and Ehsani, M.: ‘Sensorless control of BLDC motors from near-zero to high
speeds’, IEEE Trans. Power Electron., 2004, 19, (6),pp. 1635–1645
12 Tursini, M., Petrella, R., and Parasiliti, F.: ‘Initial rotor position estimation method for PM
motors’, IEEE Trans. Ind. Appl., 2003,39, (6), pp. 1630–1640
13 Jang, G.H., Park, J.H., and Chang, J.H.: ‘Position detection and start-up algorithm of a
rotor in a sensorless BLDC motor utilising inductance variation’, IEE Proc.,- Electr. Power
Appl., 2002, 149,(2), pp. 137–142
14 Lee, W.-J., and Sul, S.-K.: ‘A new starting method of BLDC motors without position
sensor’, IEEE Trans. Ind. Appl., 2006, 42, (6),pp. 1532–1538
15 Acarnley, P.P., and Watson, J.F.: ‘Review of position-sensorless operation of brushless
permanent-magnet machines’, IEEE Trans.Ind. Electron., 2006, 53, (2), pp. 352–362
16 Fairchild Semiconductor: ‘Using the ML4425/ML4426 BLDC motor controllers’,
Application note 42004, June 1996
17 Micro Linear: ‘ML4435 Sensorless BLDC motor controller datasheet’, May 2000
18 Allegro MicroSystems: ‘8904 3-Phase brushless DC motor controller/driver with backEMF sensing’, datasheet, 2003
19 Microchip: ‘Sensorless BLDC control with back-EMF filtering’,Application note AN1083,
2007
20 STMicroelectronics: ‘BLDC motor start routine for the ST72141microcontroller’,
Application note AN1276, 2000IET Electr.
24