ppt

1. Field-Oriented Control of
Induction Machine
Dr. Nik Rumzi Nik Idris
Department of Energy Conversion,
Faculty of Electrical Engineering,
Universiti Teknologi Malaysia

2. • IM is superior to DC machine with respect to
size, weight, inertia, cost, speed
Why FOC ?
• DC motor is superior to IM with respect to ease
of control
– High performance with simple control due de-coupling
component of torque and flux
• FOC transforms the dynamics of IM to become
similar to the DC motor’s – decoupling the
torque and flux components

3. Basic Principles DC machine
Current in
Current out
a
f
By keeping flux constant,
torque can be controlled
by controlling armature
current
Te = k If Ia

4. Basic Principles of IM
a
b
b’
c’
c
Stator current produce stator
flux
s
r
Interaction between stator
and rotor fluxes produces
torque
Space angle between stator
and rotor fluxes varies with
load, and speed
Stator flux induces rotor
current  produces rotor
flux

5. FOC of IM drive
Torque equation :
s
s
e i
2
p
2
3
T 


s
r
r
m
e i
L
L
2
p
2
3
T 


In d-q axis :
)
i
i
(
L
L
2
p
2
3
T sd
rq
sq
rd
r
m
e 




6. FOC of IM drive
In d-q axis :
)
i
i
(
L
L
2
p
2
3
T sd
rq
sq
rd
r
m
e 



Choose a frame such that:
r
rd
r



0
r
rq 


7. FOC of IM drive
Choose a frame such that:
r
rd
r



0
r
rq 


8. FOC of IM drive
)
i
i
(
L
L
2
p
2
3
T sd
rq
sq
rd
r
m
e 



Choose a frame such that:
r
rd
r



0
r
rq 

qs
ds
s
i
r

sq
i
rq

sd
i
rd

As seen by stator reference frame:

9. FOC of IM drive
r
sq
r
r
m
e i
L
L
2
p
2
3
T 


s
i
Choose a frame such that:
r
rd
r



0
r
rq 

qs
ds
r

dr
qr
r
sd
i
r
sq
i
)
i
i
(
L
L
2
p
2
3
T sd
rq
sq
rd
r
m
e 



Rotating reference frame:

10. FOC of IM drive
To implement rotor flux FOC need to know rotor flux position:
(i) Indirect FOC
g
r
r
g
g
r
g
s
r
r
m
g
r
r
r
)
(
j
dt
d
i
L
R
L
L
R
0 









  r
slip
r
r
sq
r
sd
r
r
m
r
r
r
)
(
j
dt
d
ji
i
L
R
L
L
R
0 







 

Synchronous speed obtain by adding slip speed and rotor speed
Rotor voltage equation:
g
r
r
g
g
r
g
r
r )
(
j
dt
d
i
R
0 







g
s
m
g
r
r
g
r i
L
i
L 


Rotor flux equation:

11. FOC of IM drive - indirect
dt
d
i
L
R
L
L
R
0 r
r
sd
r
r
m
r
r
r 



 
d component
r
slip
r
sq
r
r
m
)
(
i
L
R
L
0 



 
q component
  r
slip
r
r
sq
r
sd
r
r
m
r
r
r
)
(
j
dt
d
ji
i
L
R
L
L
R
0 







 


12. FOC of IM drive - indirect
dt
d
i
L
R
L
L
R
0 r
r
sd
r
r
m
r
r
r 



 
d component
r
slip
r
sq
r
r
m
)
(
i
L
R
L
0 



 
q component
  r
slip
r
r
sq
r
sd
r
r
m
r
r
r
)
(
j
dt
d
ji
i
L
R
L
L
R
0 







 

m
*
r
sd
L
*
i r



r
sq
r
*
r
r
m
slip i
L
R
L
)
( 



m
r
r
*
e
sq
L
L
p
3
T
4
*
i r




13. FOC of IM drive - indirect
T*
*
2/3
1/s
ir
sq*
ir
sd*
isq*
isd*
ia*
ib*
ic*
CC
VSI
slip r
+ +
Rotating frame Stationary frame
m
*
r
sd
L
*
i r



m
r
r
*
e
sq
L
L
p
3
T
4
*
i r



r
sq
r
*
r
r
m
slip i
L
R
L
)
( 



ej

14. FOC of IM drive
g
r
r
r
s
r
r
m
r
r
r
j
dt
d
i
L
R
L
L
R
0 







(ii) Direct FOC
Rotor flux can be estimated by:
Rotor flux estimated from motor’s terminal variables
s
r
r
m
e i
L
L
2
p
2
3
T 


Express in stationary frame

15. FOC of IM drive
g
r
r
r
s
r
r
m
r
r
r
j
dt
d
i
L
R
L
L
R
0 







(ii) Direct FOC
)
j
(
j
dt
)
j
(
d
i
)
ji
i
(
L
R
L
)
j
(
L
R
0 rq
rd
r
rq
rd
sq
sd
r
r
m
rq
rd
r
r















 













 dt
i
L
R
L
L
R
rq
r
sd
r
r
m
rd
r
r
rd  













 dt
i
L
R
L
L
R
rd
r
sq
r
r
m
rq
r
r
rq
d q
rd
rq




 
2
rq
2
rd
r 






16. FOC of IM drive - direct
T*
r*
2/3
isq*
isd*
ia*
ib*
ic*
CC
VSI
TC
FC
ir
sq*
ir
sd*
ej

Te
r
s
r
r
m
e i
L
L
2
p
2
3
T 


g
r
r
r
s
r
r
m
r
r
r
j
dt
d
i
L
R
L
L
R
0 







Rotating frame Stationary frame