Three phase BLDC motor

GUIDE: Prof. Jiji K S

• Amal Joseph K

• Anoop S

• Asish Jacob James

• Faheem Ali T

• Hosni K

• Jacob Mathew K

CONTENTS

INTRODUCTION

BLDC MOTOR

WORKING

PROJECT OVERVIEW

SCHEDULE

COST

REFERENCE

2

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.

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WHY BLDC..???

Better speed versus torque characteristics

High dynamic response

High efficiency

Long operating life

Noiseless operation

Higher speed ranges

Compact form

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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

WORKING

6

PROJECT OVERVIEW

Design

Analysis

Fabrication

Control circuit

Testing

7

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

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• Width of stator teeth

• Total no of conductors

• No of conductors per slot

• Area of stator slot

9

DESIGN EQUATIONS

10

11

ROTOR

12

13

14

SHAFT

ANALYSIS

From the design constraints of RDSO, analysis was done using MAXWELL 2D

15

Torque vs Speed curve

0.00 10000.00 20000.00 30000.00 40000.00n (rpm)

0.000

0.001

0.002

0.003

0.004

0.005

0.006

(N

.m)

ANSOFT

Curve Info

Output Torque

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0.00 125.00 250.00 375.00ElectricalDegree [deg]

-3.75

-2.50

-1.25

0.00

1.25

2.50

3.75

Ph

ase

Cu

rre

nt1

a [A

]

RMxprtDesign1XY Plot 1 ANSOFT

Curve Info

PhaseCurrent1aSetup1 : Performance

0.00 125.00 250.00 375.00ElectricalDegree [deg]

-3.75

-2.50

-1.25

0.00

1.25

2.50

3.75

Ph

ase

Cu

rre

nt1

b [A

]

RMxprtDesign1XY Plot 2 ANSOFT

Curve Info

PhaseCurrent1bSetup1 : Performance

0.00 125.00 250.00 375.00ElectricalDegree [deg]

-3.75

-2.50

-1.25

0.00

1.25

2.50

3.75

Ph

ase

Cu

rre

nt1

c [A

]

RMxprtDesign1XY Plot 3 ANSOFT

Curve Info

PhaseCurrent1cSetup1 : Performance

Phase A

Phase B

Phase C

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FABRICATION

TESTINGASSEMBLING

ANALYSISDESIGN

PROCUREMENT OF RAW MATERIALS

MOTOR ASSEMBLY

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STAMPING STACKINGSTACK

INSULATIONWINDING PREPPING

STATOR ASSEMBLY

19

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ROTOR ASSEMBLY

SHAFT MACHINING

HUB MACHINING

MAGNET GLUING

BEARING PRESS

29

ASSEMBLED MOTOR

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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

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POWER CIRCUIT

32

33

GATE DRIVING CIRCUIT

34

12 V

G

35

8051 SIMULATION RESULT

36

TESTING

Heating test on permanent magnet

Insulation resistance

Dielectric test

37

RESULT

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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

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BLOCK DIAGRAM

A4960

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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

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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

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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 systems43

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