Advanced Electric Drives • Disappeared from most U.S. universities

• Applications:

1

Presented by: Ted Brekken, Associate Professor

Oregon State University

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What should the electric drive do to do to keep speed constant?

3

First Course on Electric Drives

P o w e r

P ro ce ss in g

U n it (P P U )f i x e d

fo rm

m e a s u re d

s p ee d / p o s it i on

s p ee d /

p o si t io n

M o to r

E le c tr ic

D r i v e

L o a d

in p u t c o m m an d

( s pe e d / p o s it i on )

P ow e r

S ig n a l

a d ju s ta b l e

fo r mE le c tr ic S o u rce

(u ti l i t y )

S e n so r s

C o n t ro lle r

Physics-based explanation to provide a seamless transition to control

Structure of Induction Machines

ax isa

ax isb

a x isc

/2 3

/2 3

/2 3

bi

ai

ci

ax isa

ax isb

a x isc

/2 3

/2 3

/2 3

bi

ai

ci

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Induced Voltages/Currents in Rotor

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Rotor MMF Nullified by Extra Currents Drawn from the Stator

6

Electromagnetic Torque Production

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Controlling Electric Drives: Squirrel-Cage replaced by Equivalent Windings

a ax is

b ax is

c ax is

m

i a

i b

i c

iA

iC

iB

A ax is

B ax is

C ax is

m

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Representation of Stator MMF by Equivalent dq Windings

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Hypothetical d-q Windings on the Stator and the Rotor

a a x is

s ta to r

A a x is

ro to r

d a x is

m

i s d

is q

q a x isa t t

irq

i rd

m

is

ir

3

2i s d

3

2i s q

3

2i rq 3

2i rd

d

d

d a

d A

3

2sN

3

2sN

3

2sN

F ig u re 3 -3 S ta to r a n d ro to r m m f re p re se n ta t io n b y

e q u iv a le n t d q w in d in g c u r re n ts .

a a x isa a x is

s ta to r

A a x isA a x is

ro to r

d a x isd a x is

m

m

i s di s d

is q

is q

q a x isq a x isa t ta t t

irq

irq

i rdi rd

m

m

is

is

ir

ir

3

2i s d

3

2i s d

3

2i s q

3

2i s q

3

2i rq

3

2i rq 3

2i rd

3

2i rd

d

d

d a

d A

3

2sN

3

2sN

3

2sN

F ig u re 3 -3 S ta to r a n d ro to r m m f re p re se n ta t io n b y

e q u iv a le n t d q w in d in g c u r re n ts .F ig u re 3 -3 S ta to r a n d ro to r re p re s e n ta t io n b y e q u iv a le n t d q w in d in g c u r re n ts . T h e

d q w in d in g v o lta g e s a re d e f in e d a s p o s it iv e a t th e d o tte d te rm in a ls .

N o te th a t th e r e la t iv e p o s it io n s o f th e s ta to r a n d th e ro to r c u r re n t

s p a c e v e c to rs a re n o t a c tu a l , ra th e r o n ly fo r d e f in i t io n p u rp o s e s .

sd s sd m rdL i L i

sq s sq m rqL i L i

rd r rd m sdL i L i

rq r rq m sqL i L i

10

a a x is

s ta to r

A a x is

ro to r

d a x is

m

i s d

is q

q a x isa t t

irq

i rd

m

is

ir

3

2i s d

3

2i s q

3

2i rq 3

2i rd

d

d

d a

d A

3

2sN

3

2sN

3

2sN

F ig u re 3 -3 S ta to r a n d ro to r m m f re p re se n ta t io n b y

e q u iv a le n t d q w in d in g c u r re n ts .

a a x isa a x is

s ta to r

A a x isA a x is

ro to r

d a x isd a x is

m

m

i s di s d

is q

is q

q a x isq a x isa t ta t t

irq

irq

i rdi rd

m

m

is

is

ir

ir

3

2i s d

3

2i s d

3

2i s q

3

2i s q

3

2i rq

3

2i rq 3

2i rd

3

2i rd

d

d

d a

d A

3

2sN

3

2sN

3

2sN

F ig u re 3 -3 S ta to r a n d ro to r m m f re p re se n ta t io n b y

e q u iv a le n t d q w in d in g c u r re n ts .F ig u re 5 -1 S ta to r a n d ro to r m m f re p re s e n ta tio n b y e q u iv a le n t d q w in d in g c u r re n ts .

T h e d -a x is is a l ig n e d w ith r

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Vector Control: d-Axis Aligned with the Rotor Flux Linkage Axis

( ) 0rq t m

rq sq

r

Li i

L ( ) 0rq

dt

d t

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Speed and Position Loops with Vector Control

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Simulation Results of a Vector Controlled Induction Motor Drive

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Advanced Electric Drives

1. Role of Electric Drives in Renewables, Storage, Electric/Hybrid

Vehicles, variable speed drives for Energy Conservation

2. Review: AC Machines and Space Vector Theory

3. Brush-less DC Motor Drives

4. Induction Motors: Balanced Steady State Operation

5. Design and Modeling of Controllers for Torque, Speed and

Position Control

6. Speed Control of Induction Motor Drives

7. Dynamic Analysis and Modeling of Induction Machines using d-

q Axes Theory

8. Vector Control and modeling of Induction Motor Drives

9. Voltage Vector Pulse-Width Modulation

10. Direct-Torque Control and Sensor-less Drives

11. PM and IPM Synchronous-Motor Drives

12. Reluctance Drives 14