br>performance of your wind power
generators. Improvements like:
Increased generator production.
Improved generator and gearbox life.
Zero contactor replacements.
The ASC is unique among wind
generator controllers because there is no
thyristor bypass contactor. The contactor-
less design of the ASC allows the generator
voltage to adjust to the generator shaft
torque. So your generators efficiency is
enhanced in the 0 to 50% power range.
Equally important, with the ASC, the
generator produces no motoring torque
when the speed is less than synchronous.
And no motoring torque means:
Motoring power is minimal. Your net
production will be higher.
Thyristors can be enabled at any speed
less than synchronous. The need for
precison speed sensing is reduced.
The generator cant fight the brake.
The thyristors remain activated after the
brake is applied and theres no torque snap-
off when the thyristors are de-energized.
There are over 2000 ASCs installed
throughout the world, all built on the
foundation of field-proven, industry
standard components like the Enerpro
three-phase thyristor firing board.
The Enerpro ASC is available as a
complete assembly or as a circuit board kit.
So whether you are planning a new
installation or want to get the very most
out of your existing wind power system, get
the Enerpro ASC.
P
OW
E R
E
L E C T R O N ICS
C
O N T R O L
S
P E C I
A L
I S
TS O
P E R AT I N G
P
R I N C I P L E
The ASC exploits the change in generator
impedance that occurs when the rotor
drives the generator from below to above
synchronous speed. A speed switch enables
the thyristor gating at about 98% of
synchronous speed. This results in a low
level of generator excitation (about 20% of
the mains voltage). As the generator is
driven through synchronous speed, the
generator power factor angle changes
abruptly, thus naturally increasing the
thyristor conduction angle. In effect, the
generator self-excites to increase its
terminal voltage in rough proportion to the
shaft torque. Full mains voltage is reached
at typically 40% of rated power.
The ASC employs a patented generator
voltage feedback channel which stabilizes
the self-excitation process and permits the
voltage vs. torque profile to be optimized
for maximum generator efficiency.
Enerpro manufactures ASC thyristor
assemblies rated from 30 to 1200kVA with
voltage ratings to 630V. The ASC is
manufactured in the PCA style for
ratings to 210kVA and in the PCP style
for ratings to 1200kVA.
Enerpro engineers will work with the
turbine retrofit contractor or OEM to
determine the most cost-effective ASC
layout for the specific turbine and site.
P C A S
T Y L E
A
S S E M B L Y
The ASC dual thyristor modules and the
circuit boards are mounted on the flat side
of the heat exchanger extrusion. The
23.6in. x 9.9in. (600mm x 250mm)
extrusion fits over a cutout on the side or
rear of the generator control cabinet. The
heat exchanger fins extend through the
cutout. Cooling is by natural convection.
The inrush currents that occur when these
large generators are connected to the grid
are typically 12 to 15 times the load
current. The conventional method of
mitigating this stress-inducing current is to
use a soft cut-in thyristor controller to
ramp the generator voltage up to the mains
voltage and then contactor-bypassing the
thyristors.
A M
O R E
R
E L I A B L E
A N D
C
O S T
- E
F F E C T I V E
A
N S W E R
The Auto Synchronous Controller
(ASC) from Enerpro synchronizes the
generator with moderate current inrush
and then actively modulates the generator
excitation as a function of rotor torque.
N
O
M O T O R I N G
T O R Q U E
No generator motoring.
No contactor cycling.
Simple control logic: enable and inhibit
with a speed switch.
I
N C R E A S E D
P R O D U C T I O N
A N D
C A P A C I T Y
F A C T O R S
Excitation voltage is reduced when
generating at low wind speed. This
minimizes generator losses and reduces
cut-in wind velocity.
For stall-regulated turbines, no generator
motoring is needed to prevent contactor
cycling. This reduces energy
consumption.
For pitch-regulated turbines, turbine
rotation need not be stopped to prevent
contactor cycling. This increases energy
production.
A
U T O
S
Y N C H R O N O U S
C
O N T R O L L E R
A d v a n c i n g t e c h n o l o g y a n d t h e d r i v e f o r r e d u c e d c o s t p e r
K W o f c a p a c i t y h a v e l e d t o a s t e a d y i n c r e a s e i n w i n d -
p o w e r e d g e n e r a t o r r a t i n g s . T u r b i n e s f o r p r e s e n t - d a y w i n d
p l a n t s r a n g e f r o m 2 5 0 k V A t o 1 2 0 0 k V A .
E
N E R P R O 1
20
ASCIB-4
INTERFACE
BOARD
1
2
3
5
6
J1
1
2
3
4
J2
J3
J6
1
20
1
2
4
5
7
8
J1
1
2
4
5
7
8
J2
+A
+B
+C
-A
-B
-C
J4
FCOG6100
THREE-PHASE
THYRISTOR
FIRING BOARD
3 5
1
J1
3
1
J2
3
1
J3
3
AUTO SYNCHRONOUS CONTROLLER ASSEMBLY
TSB-3 TRANSIENT SUPPRESSION BOARD
+A
-A
+B
-B
+C
-C
G
g
k
BIAS
MOTOR
ENABLE
MOTOR
+12
COM
480 V
60 Hz
120 VAC HI
120 VAC LO
ENABLE CMD
(120 VAC)
MOTOR CMD
(120 VAC)
120 VAC LO
ENABLE STATUS FEEDBACK
Optional
Relay
Contact
Control
g k
shunt
trip
Fuse holders are mounted on the extru-
sion when style 132 thyristor modules
are installed. A separate fuse panel is
provided when the larger style 161,
250 or larger thyristor modules are
installed.
P C P S
T Y L E
A
S S E M B L Y
The three dual thyristor modules are
mounted on individual extrusions which
are in turn attached to a formed 28.0 in. x
17.1 in. (711 mm x 433 mm) aluminum
panel. The circuit boards are also mounted
on the panel. The assembly fits over a cut-
out in the generator control cabinet with
the extrusion fins extending through the
cutout. The PCP style extrusions may be
cooled by natural convection or forced air.
T H Y R I S T O R S
The ASC product line is based on
industry standard dual isolated base
thyristor modules. Wafer diameters
range from 15mm to 52mm with peak
one cycle surge ratings from 1750A to
17,000A.
Depending upon the mains voltage, the
peak blocking voltage for the thyristors is
between 1600V and 2200V.
F C O G 6 1 0 0 F
I R I N G
B
O A R D
The industry-standard FCOG6100 is used
in a wide variety of motor and generator
controllers and large industrial power
supplies. It is based on a phase-locked
loop digital LSI device which reduces the
component count while improving
reliability. It provides excellent gate pulse
balance. Its immune to mains voltage
disturbances and is unaffected by phase
sequence.
The Model ASC-PCA (shown here) is rated for 30 kVA to
210 kVA applications. The Model ASC-PCP, pictured on
the cover, is rated for applications from 250 kVA to 1.2 MVA.
A S C I B - 4 I
N T E R F A C E
B
O A R D
This interface board provides the
following functions:
Thyristor enable in response to a 120V
control voltage or contact closure.
Generator excitation adjustment.
Generator voltage feedback to ensure
stability at part load when the
generator voltage is less than the mains
voltage.
Excitation boost to prevent overcurrent
or pullout when synchronizing during
high acceleration.
Increases the generator excitation to
produce limited motoring torque in
response to a 120V control voltage.
An enable status relay contact closure
to signal that the ASC has responded
to the enable command.
Optional speed sensing circuit.
Board-mounted push-button switches
are provided to manually enable the
thyristors or to motor the generator.
Board-mounted potentiometers permit
adjustment of the generator excitation
voltage and motoring current. LEDs
indicate +12V supply status, mains
voltage phase loss and thyristor enable.
T S B - 3 S
N U B B E R
B
O A R D
The snubber board mounts three RC
MOV circuits which limit both the rate-
of-rise and the peak thyristor voltage of
each thyristor module. Rate-of-rise is
controlled with a series RC circuit in
parallel with each thyristor pair. The
snubber capacitor is a low inductance
corona-free unit rated for high pulse
current. Peak thyristor voltage is limited
with an MOV. The snubber capacitance,
resistor value and power rating and the
MOV energy rating are selected according
to the rating of the controller. The
snubber board is fused to prevent damage
in the event of an MOV failure. Board-
mounted LEDs verify the integrity of
the snubber circuit.
Typical ASC
Connection
Diagram O
R D E R I N G
G
U I D E
E n e r p r o
Applications Engineers are available by telephone or
fax to answer any questions about this or any other Enerpro
power electronics control package.
ENERPRO, INC.
5780 Thornwood Drive
Goleta, CA 93117 (USA)
800-576-2114
Telephone: 805/683-2114
Fax: 805/964-0798
U K & E
U R O P E
Power Products International, Ltd.
Commerce Way
Edenbridge, Kent TN8 6ED
United Kingdom
Telephone: (0732) 866424
Fax: (0732) 866399
M
E X I C O
& S
O U T H
A
M E R I C A
CEISA, S.A. de C.V.
Arquimedes 28
Mexico, D.F. 11560
Telephone: 280 2662
Fax: 280 5775
H
O N G
K
O N G
, M
A C A U
, C
H I N A
( P R C )
Tackoh Enterprises (H.K.)
Rm 1410, Arion Commercial Center
2-12 Queens Road, West
Hong Kong
Telephone: 5430186
Fax: 5422114
I
N D I A
Jyoti, Ltd.
Regd. Office: Industrial Area
P.O. Chemical Industries
Vadodara 390 003
India
Telephone: 91 265 321041
Fax: 91 265 337866
© Copyright 1995, Enerpro Incorporated
PRINTED IN USA
M
O D E L
Auto Synchronous Controller
C
O D E
k V A R
A T I N G
X X X
e.g.:
0 3 0
=