Project report on design and fabrication of three phase bldc motor and the control circuit associated with it.

1. GUIDE: Prof. Jiji K S
• Amal Joseph K
• Anoop S
• Asish Jacob James
• Faheem Ali T
• Hosni K
• Jacob Mathew K

2. CONTENTS
 INTRODUCTION
 BLDC MOTOR
 WORKING
 PROJECT OVERVIEW
 SCHEDULE
 COST
 REFERENCE
2

3. INTRODUCTION
DC motors – permanent magnet stator and
armature is an electromagnet
They need brushes as the supply is given to
rotating armature.
Disadvantages- wearing of brushes, noise,
sparking, limitations in max speed and no of
poles.
Brushless DC (BLDC) motor- permanent
magnet rotor and supply is given to stator.
3

4. WHY BLDC..???
 Better speed versus torque characteristics
 High dynamic response
 High efficiency
 Long operating life
 Noiseless operation
 Higher speed ranges
Compact form
4

5. BLDC MOTOR
 No commutators or
brushes
 Position of coils with
respect to the magnetic
field is sensed
electronically.
 Current is commutated
through electronic
switches to appropriate
phases. 5

6. WORKING
6

7. PROJECT OVERVIEW
Design
Analysis
Fabrication
Control circuit
Testing
7

8. DESIGN
110 V, 25W, 600RPM
STATOR
• No. of phases : 3
• No. of slots : 6
• No. of turns : 435-480
• Stack length : 11.5 ± 0.5
• Stack outer dia : 87mm
• Stack inner dia :56.2 ± 0.2mm
8

9. • Width of stator teeth
• Total no of conductors
• No of conductors per slot
• Area of stator slot
9
DESIGN EQUATIONS

10. 10

11. 11

12. ROTOR
12

13. 13

14. 14
SHAFT

15. ANALYSIS
From the design constraints of RDSO, analysis
was done using MAXWELL 2D
15

16. Torque vs Speed curve
0.00 10000.00 20000.00 30000.00 40000.00
n (rpm)
0.006
0.005
0.004
(N.m)
0.003
0.002
0.001
0.000
ANSOFT
Curve Info
Output Torque
16

17. 0.00 125.00 250.00 375.00
ElectricalDegree [deg]
3.75
2.50
1.25
0.00
PhaseCurrent1a [A]
-1.25
-2.50
-3.75
XY Plot 1 RMxprtDesign1 ANSOFT
Curve Info
PhaseCurrent1a
Setup1 : Performance
0.00 125.00 250.00 375.00
ElectricalDegree [deg]
3.75
2.50
1.25
0.00
PhaseCurrent1b [A]
-1.25
-2.50
-3.75
XY Plot 2 RMxprtDesign1 ANSOFT
Curve Info
PhaseCurrent1b
Setup1 : Performance
0.00 125.00 250.00 375.00
ElectricalDegree [deg]
3.75
2.50
1.25
0.00
PhaseCurrent1c [A]
-1.25
-2.50
-3.75
XY Plot 3 RMxprtDesign1 ANSOFT
Curve Info
PhaseCurrent1c
Setup1 : Performance
Phase A
Phase B
Phase C
17

18. FABRICATION
ASSEMBLING TESTING
MOTOR ASSEMBLY
DESIGN ANALYSIS
PROCUREMENT OF
RAW MATERIALS
18

19. STAMPING STACKING
STACK
INSULATION
WINDING PREPPING
STATOR ASSEMBLY
19

20. 24
ROTOR ASSEMBLY
SHAFT
MACHINING
HUB
MACHINING
MAGNET
GLUING
BEARING PRESS

21. 29

22. ASSEMBLED MOTOR
30

23. CONTROL CIRCUIT
Open loop control
Motor is started at a slower speed and slowly
brought to its rated speed
Power circuit – 3 phase inverter using mosfet
Gate driving circuit – using optocoupler
4 isolated gate driver circuits are used to drive
the mosfets
31

24. POWER CIRCUIT
32

25. 33

26. GATE DRIVING CIRCUIT
34
12 V
G

27. 35

28. 8051 SIMULATION RESULT
36

29. TESTING
Heating test on permanent magnet
Insulation resistance
Dielectric test
37

30. RESULT
38

31. FUTURE DEVELOPMENTS
For motors of rating above 300 watts
specialized sensor less driver ic’s can be used.
Back emf detection principle
One of the windings will always be in floating
state
Back emf in the floating winding can be used
to know which phase has to be excited
39

32. BLOCK DIAGRAM
A4960
40

33. SCHEDULE
DATE WORK PROGRESS
8/10/2012 Collected required study materials
14/11/2012 Started design procedure
23/1/2013 Technical assistance from KEL
26/2/2013 Placed order for motor components
10/4/2013 Completed winding process
26/4/2013 Completed motor assembly
29/4/2013 Final submission
41

34. MANUFACTURING COST
ITEM PRICE QUANTITY TOTAL
M-45 CRNGO silicon
steel
400/kg 680 gm. 272
Rotor magnet 125 1 125
Stamping 300/ hr. 5 hr. 1500
29 SWG Cu wire 740/kg 175 gm. 130
6000 2RS bearing 35 1 35
Lathe work 3000 1 3000
IC 8051 75 1 75
Circuit components 1785 1 1785
Total 6972
42

35. REFERENCE
• RDSO spec sheet for 400mm sweep bldc fan
• Brushless DC (BLDC) Motor Fundamentals-Padmaraja
Yedamale Microchip
• Design and Development of Three Phase Permanent
Magnet Brushless DC (PM BLDC)-Srinivas Mallapalli-
GE Global Research, GE India Technology Centre
• Design of a Compact BLDC motor for Transient
Applications Y.K. Chin, W.M. Arshad, T. Bäckström &
C. Sadarangani
• A4960 data sheet by allegro micro systems
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