Transcript Lecture Notes EEE 360 - Warsaw University of Technology

EEE 360
Energy Conversion and
Transport
George G. Karady & Keith Holbert
Chapter 6
Synchronous Machine
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Lecture 14
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6.1 Construction
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6.1.1 Round Rotor
Generator
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Synchronous Machines
Generator
Exciter
Figure 6.1 View of a two-pole round rotor generator and exciter.
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Synchronous Machines
Stator with
laminated iron core
B
A
Slots with
phase
winding
CA+
+
S
B-
B+
-
+
N
-
Rotor with
dc winding
+
+
+
-
-
-
A-
C+
C
Figure 6.2
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Major components of a round rotor two-pole generator
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Synchronous Machines
Figure 6.3 Cross-section of a large turbo generator. (Courtesy Westinghouse)
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Synchronous Machines
Metal frame
Laminated iron
core with slots
Insulated copper
bars are placed in
the slots to form
the three-phase
winding
Figure 6.4
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Details of a generator stator.
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Synchronous Machines
Figure 6.5 Rotor block of a large generator. (Courtesy Westinghouse)
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Synchronous Machines
Figure 6.6 Generator rotor with conductors placed in the slots.
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Synchronous Machines
Steel
retaining
ring
Shaft
Shaft
Wedges
DCcurrent
current
DC
terminals
terminals
Figure 6.7 Large generator rotor completely assembled. (Courtesy Westinghouse)
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6.1.2 Salient pole generator
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Synchronous Machines
Stator with
laminated iron core
B+
CN
-
A+
Rotor with
dc winding
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A-
S
B-
Figure 6.8
+
+
+
+
+
C+
Slots with
phase
winding
Two-pole salient pole generator concept.
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Synchronous Machines
A-
B+
C+
C-
N
-
+
+
+
+
-
A+
B-
S
S
-
+
+
B-
A+
-
+
+
C-
N
C+
A-
B+
Figure 6.12 Four-pole salient pole generator concept.
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Synchronous Machines
Figure 6.9Stator of a large salient pole hydro generator; inset
shows the insulated conductors and spacers.
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Synchronous Machines
Figure 6.10 Large hydro generator rotor with view of the vertical poles.
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Synchronous Machines
Slip
rings
Pole
Fan
DC excitation
winding
Figure 6.11 Rotor of a four-pole salient pole generator.
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Synchronous Machines
Exciter rotor
Rotating rectifier
Generator
Exciter stator

Idc
Field
winding
Phase
windings
Stationary
Rotates
Figure 6.13 Concept of the brushless exciter system
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6.2 Operating Concept
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Synchronous Machines
Flux f
nsy
B+
C+
N
+
+
-
A+
A-
+
-
+
-
B-
S
C+
Figure 6.14 Operating concept of a synchronous generator
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Synchronous Machines
Maximum flux linkage with phase A
C-
No flux linkage with phase A
B+
-
C-
+
B+
-
+
-
N
N
A+
+
-
+
-
A-
A+
+
S
-
B-
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A-
+
+
-
C+
(a) Flux is perpendicular to phase A
Figure 6.15
-
S
B-
+
C+
(b) Flux is parallel to phase A
Rotation produced flux linkage variation.
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Synchronous Machines
rot
link
t
nsy
B+
C+
N
+
+
-
A+
-
30
+
-
S
A-
+
-
B-
C+
Figure 6.16 Rotating flux linkage to phase A.
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Synchronous Machines
Main rotating flux
f
n sy 
p
2
  2 nsy
Es (t )   N sta  rot  sin( t )
 N sta  rot  cos( t  90)
E sta 
 link (t )   rot cos( t )
E s (t )  N sta
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d  link (t )
dt
N sta  rot 
2
The rotating flux generates
the induced voltage
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Synchronous Machines
nsy
B+
C+
N
+
Field flux f
-
A+
A-
+
-
30
+
-
S
+
-
B-
Armature
flux ar
C+
Figure 6.17 Field (Φf) and load generated (Φar) rotating fluxes.
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Synchronous Machines
Armature flux
I arm (t )  2 I sta cos( t )
 arm (t )   ar cos( t )
E ar (t )  N sta
E arm 
Load current generates a
rotating flux reducing the
main flux and induced
voltage
d arm (t )
  N sta  ar  sin ( t )
dt
N sta  ar 
2
Vt  E sta  E arm
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Synchronous Machines
Armature flux
E ar (t )  Larm
dI
arm
(t )
dt
  Larm  2 I sta
  X arm
X arm 
d
dt
sin( t )
 Larm
2 I sta cos( t )
2 I sta sin( t )
N sta  ar 
2 I sta
X syn  X arm  X leakage
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Synchronous Machines
Single phase
equivalent circuit
Earm syn  I sta ( j X syn )
Vt  Esta  Earm syn  Esta  I sta j X syn
Xsyn
Rsta
Flux
Esta
Ista
Vt
DC
Figure 6.18 Single-phase equivalent circuit of a synchronous generator.
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