outlook - ieadcmachine).pdf · 2019-02-13 · l8: dc machine theory and control l4: 13-feb-2019...
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![Page 1: Outlook - IEADCMachine).pdf · 2019-02-13 · L8: DC machine theory and control L4: 13-FEB-2019 Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 2 Outlook •Operation principle](https://reader034.vdocuments.mx/reader034/viewer/2022050305/5f6e407660180023f337d68f/html5/thumbnails/1.jpg)
L8: DC machine theory and control
L4: 13-FEB-2019
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 2
Outlook
• Operation principle
• DC machine constructions
• Armature winding and commutation
• DC machine parameters and model
• Machine characteristics
• Torque and speed control of DC machine
![Page 2: Outlook - IEADCMachine).pdf · 2019-02-13 · L8: DC machine theory and control L4: 13-FEB-2019 Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 2 Outlook •Operation principle](https://reader034.vdocuments.mx/reader034/viewer/2022050305/5f6e407660180023f337d68f/html5/thumbnails/2.jpg)
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 3
Rotating coil in magnetic field
• If the coil rotates in a magnetic field, the flux linking the coil will be an alternating quantity
• Connection via sliprings– alternating voltage
• Connection via commutator – “rectified”voltage
B
eθ
B
e
θ
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 4
Working principle
221
222
00
BdAede
BlrBBlrBlue
av
• Current carrying conductor in magnetic field
• Magnetic field created by field coil or permanent magnets
• As the armature rotates the 2 coil sides move in the magnetic field
S N B
iBilrdT
BBilrBlirFrT
av
2
21
222
0
B
I
F
![Page 3: Outlook - IEADCMachine).pdf · 2019-02-13 · L8: DC machine theory and control L4: 13-FEB-2019 Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 2 Outlook •Operation principle](https://reader034.vdocuments.mx/reader034/viewer/2022050305/5f6e407660180023f337d68f/html5/thumbnails/3.jpg)
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 5
DC machine constructions A
• Permanent magnet DC machines– Small machines
– Three coils, 120 shifted
– PM on stator or on rotor
• Commutation– Mechanic via commutator
– Electric via 3-phase bridge
• Torque generation– SN arrangement of PM for field ψ
– Coil energizing I for torque T
– Torque direction and energizingsequence
+A
-B
+B
-C
+C
-A
+A
-B
+B
-C
+C
-A
Brushed DC motor
Brushless DC motor
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 6
DC machine constructions B
• Magnetized, loaded & armature field
![Page 4: Outlook - IEADCMachine).pdf · 2019-02-13 · L8: DC machine theory and control L4: 13-FEB-2019 Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 2 Outlook •Operation principle](https://reader034.vdocuments.mx/reader034/viewer/2022050305/5f6e407660180023f337d68f/html5/thumbnails/4.jpg)
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 7
Commutator
Stator field fluxRotor flux
Rotor
Commutator
Rotor fluxStator field flux
Rotor
Comm
utato
r
Stator field fluxRotor flux
Rotor
Commutator
RotorCommutator
Stator field flux
Brushes
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 8
DC machine construction C• Stator with salient poles &
cylindrical rotor
• Armature winding, field and armature reaction
• Commutating (inter) pole –neutralize flux distortion in the neutral plane caused by armature reaction
• Compensating winding –embedded in pole phases, in series with the armature, neutralizing the cross-magnetizing field
If
Ia Armature field
Excitation field
![Page 5: Outlook - IEADCMachine).pdf · 2019-02-13 · L8: DC machine theory and control L4: 13-FEB-2019 Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 2 Outlook •Operation principle](https://reader034.vdocuments.mx/reader034/viewer/2022050305/5f6e407660180023f337d68f/html5/thumbnails/5.jpg)
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 9
Armature winding
• Layouts– Lap winding– Wave winding
• Current distribution rectangular
• MMF distribution triangular
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 10
Field winding and excitation
• Separately excited
• Self excited– Series wound
– Shunt wound
– Compound wound
• Long shunt
• Short shunt
au fu
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Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 11
Series motor• Rotor current = the field
current• Torque is independent of
current direction• Used in many handhold
machines• Used as traction motors
for railways
+ ua -
2amam iLiT
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 12
DC machine model
• Armature (rotor)
• Excitation (stator)
• Torque (gap)
• Torque (shaft)
ma
aaaa dt
diLiRu
T=m·ia
fmffmm
fffff
LLLiLdt
diLiRu
Js
TTdt
J
TT
TTdt
dJJ
dt
d
elel
lel
Back EMF
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Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 13
Summary of DC machine
• Rotation Commutator on the rotor shaft
• Voltage Proportional to motorspeed
• Torque Proportional to rotor current
m
0a
x
y
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 14
0 1 2 3 4 5 6 7 8 9 100
5
10
15
20
25
volta
ge,
u [V
]
time, t [s]
T
ua
ea
0
0.5
1
1.5
2x 10
4
spee
d, n
[rp
m]
n
0
50
100
150
200
250
curr
ent,
Ia
[A]
I
0 1 2 3 4 5 6 7 8 9 100
0.5
1
1.5
2
2.5
3
torq
ue,
T [
Nm
]
Brushed PM DC machine example
• Parameters– Voltage Ua=24V
– Speed n=18000 rpm
– Flux linkage ψ=E/ω
– R, L, J arbitrary, b=0
1
J.s
1
L.s
e
ia
T
w
t
M
b
M
R
Tm ec
ua
Clock
0 2000 4000 6000 8000 10000 12000 14000 16000 180000
0.5
1
1.5
2
2.5
3
torq
ue,
T [
Nm
]
speed, n [rpm]0 2000 4000 6000 8000 10000 12000 14000 16000 18000
0
500
1000
1500
pow
er,
P [
W]
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Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 15
DCM
• Uf=200V, Rf=200Ω, if=1A,Psim=1.23Vs
• Tload=10Nm
Psif
EXCIT AT ION FIELD DYNAM ICS
ANCHOR DYNAMICS
ROT OR DYNAMICS
Rf
i f = f (Psif )
1
J.s
1
L.s
e
ia
T
ie
w
psim
t
1/s
bR
K
uf
T mec
ua
Clock
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
50
100
150
200
volta
ge,
u [V
]
time, t [s]
T
ua
ea
0
500
1000
1500
spee
d, n
[rp
m]
n
0
10
20
30
40
50
60
70
curr
ent,
Ia
[A]
I
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
10
20
30
40
50
60
70
torq
ue,
T [
Nm
]
-200 0 200 400 600 800 1000 1200 14000
20
40
60
80
torq
ue,
T [
Nm
]
speed, n [rpm]-200 0 200 400 600 800 1000 1200 1400
0
1000
2000
3000
4000
pow
er,
P [
W]
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 16
DCM Drive without PEC
Psif
EXCIT AT ION FIELD DYNAM ICS
ANCHOR DYNAM ICS
ROTOR DYNAMICS
CURRENT PIE REGULAT ORSPEED PI REGULATOR
vol tage l im it
torque
li mi tati on
Rf
Kpw Ki w
if = f(Psif )
1
Psim
current
reference
current lim itati on
Kaw
Kai
1
J.s
1
L.s
e
ia
T
iar
ua
ie
w
p sim
t Kpi
Ki i
1/s
bR
K
T
z-1
T
z-1
wref
uf
T mec
Clock
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
50
100
150
200
volta
ge,
u [V
]
time, t [s]
T
ua
ea
0
500
1000
1500
spee
d, n
[rp
m]
n
0
5
10
15
20
curr
ent,
Ia
[A]
I
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
5
10
15
20
25
torq
ue,
T [
Nm
]
• Free acceleration under current limit
• P and PE regulators only!
-200 0 200 400 600 800 10000
5
10
15
20
25
torq
ue,
T [
Nm
]
speed, n [rpm]-200 0 200 400 600 800 1000
0
200
400
600
800
1000
1200
pow
er,
P [
W]
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Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 17
Torque control
• Torque is proportional to current
• Current control– Direct current control
(DCC)
– Sampled current control (SCC) PIE regulator
forwardFeed
Integral
kn
ns
s
oportionals
kn
ns
s
s
keniniT
R
LT
kikiR
T
L
keniniRkikiR
T
L
keT
kikiLkiR
kikiR
keT
kikiL
kikiRku
)()()(*
2
)()(*2
)()()(*)()(*2
)()()(*
)(2
)()(*
)()()(*
2
)()(*)(*
1
0Pr
1
0
i
increase
rest
decrease
[1, -1]
[1,1] or [-1, -1]
[-1,1]
[sa, sb]
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 18
Field weakening
nomrrr
nomrnomm
nomrrnomm
m
nommnomra
mra
if
if
e
e
,,
,
,,*
,,max,
nom max
m
fi
*fi
Voltage, Power
Torque, Flux
Speed
Rotor current
![Page 10: Outlook - IEADCMachine).pdf · 2019-02-13 · L8: DC machine theory and control L4: 13-FEB-2019 Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 2 Outlook •Operation principle](https://reader034.vdocuments.mx/reader034/viewer/2022050305/5f6e407660180023f337d68f/html5/thumbnails/10.jpg)
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 19
Electric drive system with DCM
• 1QC armature winding – uni-directional torque and speed
• 2QC armature winding – acceleration and regenerative breaking
• 4QC armature winding – bi-directional torque and speed
Lund University / LTH / IEA / AR / EIEN25 /2019-02-13 20
Exercises on DC machine (4)
• PE ExercisesWithSolutions2019b vers 190206
• DC machine construction (4.16a)
• DC machine equations (4.16b-c)
• DC machine parameters and performance (4.17)
• DC machine control and parameters (4.18)
• Electric drive system specification for DC machine