Power Eelectronic Drives

7/23/2019 Power Eelectronic Drives

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ELECTRICAL DRIVES:ELECTRICAL DRIVES:

An Application of Power ElectronicsAn Application of Power Electronics


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CONTENTSCONTENTS

Power Electronic SystemsPower Electronic Systems

Modern Electrical Drive SystemsModern Electrical Drive Systems

Power Electronic Converters in Electrical DrivesPower Electronic Converters in Electrical Drives:: DC and AC Drives:: DC and AC Drives

Modeling and Control of Electrical DrivesModeling and Control of Electrical Drives


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Power Electronic Systems

What is Power Electronics ?

A feld o Electrical Engineering that deals with theapplication o power semiconductor devices or thecontrol and conversion o electric power

PowerElectronicsConverters

Load

Controller

Output- AC- DC

Input

Source-AC-DC-unregulated

Reference

POWER ELECTRONIC

CONVERTERS the

heart of power a power

electronics system

sensors


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Why Power Electronics ?

Power

ElectronicsConverters

sensors

Load

Controller

Output- AC

- DC

Input

Source-AC-DC-unregulated

Reference

IDEALLYLOSSLESS


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Why Power Electronics ?

Other actors:

Improvements in power semiconductors abric

Decline cost in power semiconductor

Advancement in semiconductor abrication

AICs !P"A DPs

!aster and cheaper to implementcomple# algorithm

Power Integrated $odule %PI$&' IntelligentPower $odules %IP$&


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So!e A""lications o# Power Electronics :

Power rating of ! " #porta$le e%uipment&

'ens or hundreds "atts #Power supplies for computers (office e%uipment&

'ypically used in systems re%uiring efficient control and con)ersion of

electric energy*

Domestic and Commercial Applications

Industrial Applications

'elecommunications'ransportation

+eneration, 'ransmission and Distri$ution of electrical energy

" to ." * dri)es

/undreds of ." in DC transmission system #/0DC&


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Modern Electrical Drive Systems

Classic Electrical Drive for Variable Speed Application :

1uly

Inefficient

infle2i$le


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PowerElectronicConverters

Load

$otor

ControllerReference

POWER IN

feedback

Tpical !odern Electric Drive Sste"s

Power 3lectronic Con)erters

3lectric 3nergy

- 4nregulated -

3lectric 3nergy

- Regulated -

3lectric .otor

3lectric

3nergy.echanical

3nergy


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E#a"ple on VSD application

motor pump

valve

Supply

Constant speed 0aria$le Speed Dri)es

Po$er

In

Po$er lossMainly in valve

Po$er o%t


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Po$er

In


Po$er o%t

motor pump

valve

Supply

motorPEC pump

Supply


Po$er

In

Po$er loss

Po$er o%t


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Po$er

In


Po$er o%t

Po$er

In

Po$er loss

Po$er o%t

motor pump

valve

Supply

motorPEC pump

Supply




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3lectric motor consumes more than half of electrical energy in the 4S

&i#ed speed Variable speed

/O" 5

Impro)ements in energy utili6ation in electric motors gi)e large

impact to the o)erall energy consumption

Replacing fi2ed speed dri)es with )aria$le speed dri)es

4sing the high efficiency motors

Impro)es the e2isting power con)erter$ased dri)e systems



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DC drives* 3lectrical dri)es that use DC motors as the prime mo)er

Regular maintenance, hea)y, e2pensi)e, speed limit

AC drives* 3lectrical dri)es that use AC motors as the prime mo)er

7ess maintenance, light, less e2pensi)e, high speed


Overvie$ of AC and DC drives

3asy control, decouple control of tor%ue and flu2

Coupling $etween tor%ue and flu2 )aria$le spatial angle

$etween rotor and stator flu2


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1efore semiconductor de)ices were introduced #!89:&

AC motors for fi2ed speed applications DC motors for )aria$le speed applications

After semiconductor de)ices were introduced #!8;:s&

0aria$le fre%uency sources a)aila$le AC motors in )aria$le

speed applications

Coupling $etween flu2 and tor%ue control Application limited to medium performance applications

fans, $lowers, compressors scalar control

/igh performance applications dominated $y DC motors

tractions, ele)ators, ser)os, etc




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After )ector control dri)es were introduced #!8


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Power Electronic Converters in ED Systems

Converters for !otor Drives

#some possi$le configurations&

DC Dri)es AC Dri)es

DC SourceAC Source

AC(DC(DC

AC(DC

AC Source

Const>

DC

0aria$le

DC

AC(DC(AC

AC(AC

?CC @CC

DC Source

DC(ACDC(DC(

AC

DC(DC

DC(AC(

DC


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Converters for !otor Drives

Configurations of Power 3lectronic Con)erters depend on*

Sources a)aila$le

'ype of .otors

Dri)e Performance - applications

- 1raing

- Response

- Ratings


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DC DRIVES

A)aila$le AC source to control DC motor #$rushed&

AC(DC(DCAC(DC

Controlled Rectifier Single-phase 'hree-phase

4ncontrolled Rectifier

Single-phase 'hree-phase

DC-DC Switched mode !-%uadrant, -%uadrant B-%uadrant

Control Control


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DC DRIVES

0o

0o

= cosV2

V mo

=

cosV3

V m,LL

o

A)erage )oltage

o)er !:ms

A)erage )oltage

o)er =>== ms

9:/6

!-phase

9:/6=-phase

AC(DC

0.4 0.405 0.41 0.415 0.42 0.425 0.43 0.435 0.44-400

-200

0

200

400

0.4 0.405 0.41 0.415 0.42 0.425 0.43 0.435 0.440

5

10

0.4 0.405 0.41 0.415 0.42 0.425 0.43 0.435 0.44

-500

0

500

0.4 0.405 0.41 0.415 0.42 0.425 0.43 0.435 0.44

0

10

20

30


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DC DRIVES

0o

0o

= cosV2

V mo

8:o !== ms

9:/6

!-phase

9:/6=-phase

!


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DC DRIVES

AC(DC

Ia

Q1Q2

Q3 Q4

Vt

3-phase

supply

0t

ia

- Operation in %uadrant ! and B only


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DC DRIVES

AC(DC

Q1Q2

Q3 Q4

T

3-phase

supply

3-

phase

supply

(

Vt


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DC DRIVES

AC(DC

Q1Q2

Q3 Q4

T

F1

F2

R1

R2

+ Va -

3-phase

supply


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DC DRIVES

AC(DC

Cascade control structure with armature re)ersal #B-%uadrant&*

peedcontrolle

r

CurrentControlle

r

!iring

Circuit

Armature

reversal

iD

iD,ref

iD,ref

iD,

re


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DC DRIVES

AC(DC(DC

control


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'! conducts va) Vdc

E!E

Va

Ia

'!

'

D!

+

Va

-

D

ia

0dc

DC DRIVES

AC(DC(DC DC-DC* 'wo-%uadrant Con)erter



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E!E

Va

Ia

'!

'

D!

+

Va

-

D

ia

0dc

D conducts va) *

Va Eb

'! conducts va) Vdc

+%adrant , 'he a)erage )oltage is made larger than the $ac emf

DC DRIVES




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E!E

Va

Ia

'!

'

D!

+

Va

-

D

ia

0dc

D! conducts va) Vdc

DC DRIVES




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E!E

Va

Ia

'!

'

D!

+

Va

-

D

ia

0dc

' conducts va) *

VaEb

D! conducts va) Vdc

+%adrant - 'he a)erage )oltage is made smallerr than the $ac emf, thus

forcing the current to flow in the re)erse direction

DC DRIVES




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DC DRIVES


)c

)tri)c

)A

-

0dc

:



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leg A leg 1

+ Va

E!

EB

E=

E

D! D=

DDB

0dc

va= Vdc when Q1 and Q2 are ON

Positive c%rrent


DC DRIVES

AC(DC(DC DC-DC* @our-%uadrant Con)erter


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leg A leg 1

+ Va

E!

EB

E=

E

D! D=

DDB

0dc

va= -Vdc when D and D! are ON


va= " when c#rrent $reewheels thro#%h Q and D

Positive c%rrent


DC DRIVES



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Positive c%rrent

va= Vdc when D1 and D2 are ON

Ne.ative c%rrent

leg A leg 1

+ Va

E!

EB

E=

E

D! D=

DDB

0dc


DC DRIVES



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Positive c%rrent

va= -Vdc when Q and Q! are ON

va= Vdc when D1 and D2 are ON


Ne.ative c%rrent

leg A leg 1

+ Va

E!

EB

E=

E

D! D=

DDB

0dc


DC DRIVES



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Power Eelectronic Drives

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