U.S. patent application number 15/723044 was filed with the patent office on 2018-01-25 for system for turbomachine vane control.
The applicant listed for this patent is General Electric Company. Invention is credited to Cyron Frank Kay, John Carver Maters.
Application Number | 20180023485 15/723044 |
Document ID | / |
Family ID | 50931085 |
Filed Date | 2018-01-25 |
United States Patent
Application |
20180023485 |
Kind Code |
A1 |
Kay; Cyron Frank ; et
al. |
January 25, 2018 |
SYSTEM FOR TURBOMACHINE VANE CONTROL
Abstract
A gas turbine system includes a compressor. The compressor has a
plurality of inlet guide vanes disposed at an inlet of the
compressor. Furthermore, the compressor may have at least one
unison ring coupled to a plurality of variable stator vanes
disposed between the inlet and an outlet of the compressor. The gas
turbine system includes a first actuator that may adjust a first
pitch of the plurality of inlet guide vanes and a second actuator
that may adjust a second pitch of the plurality of variable stator
vanes. A first electric motor may drive the first actuator, while a
second electric motor may drive the second actuator.
Inventors: |
Kay; Cyron Frank;
(Simpsonville, SC) ; Maters; John Carver;
(Liberty, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
50931085 |
Appl. No.: |
15/723044 |
Filed: |
October 2, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13721000 |
Dec 19, 2012 |
9777641 |
|
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15723044 |
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Current U.S.
Class: |
415/148 ;
415/155 |
Current CPC
Class: |
F02C 9/20 20130101; F16D
2125/58 20130101; F01D 17/162 20130101 |
International
Class: |
F02C 9/20 20060101
F02C009/20; F01D 17/16 20060101 F01D017/16 |
Claims
1. A gas turbine system, comprising: a compressor, comprising: a
plurality of inlet guide vanes disposed at an inlet of the
compressor; and at least one unison ring, wherein each unison ring
is coupled to a plurality of variable stator vanes disposed between
the inlet and an outlet of the compressor; a first actuator
configured to adjust a first pitch of the plurality of inlet guide
vanes; a second actuator configured to adjust a second pitch of the
plurality of variable stator vanes; a first electric motor
configured to drive the first actuator in response to control by a
first motor controller; and a second electric motor configured to
drive the second actuator in response to control by a second motor
controller, wherein the first and second motor controllers are
respectively configured to control the first and second actuators
independently in coordination with one another based on a first
position feedback from the first actuator and a second position
feedback from the second actuator, and wherein the first and second
motor controllers are configured to control the first and second
actuators independently in coordination with one another to help
achieve a targeted flow and pressure profile in the compressor.
2. The gas turbine system of claim 1, wherein the at least one
unison ring comprises first and second unison rings coupled
together by a torque tube.
3. The gas turbine system of claim 2, wherein the first unison ring
is coupled to a first plurality of variable stator vanes disposed
at a first stator pitch, the second unison ring is coupled to a
second plurality of variable stator vanes disposed at a second
stator pitch, and the second actuator is configured to adjust the
first and second stator pitches by adjusting the torque tube.
4. The gas turbine system of claim 3, wherein the first and second
stator pitches are configured to move in a predetermined ratio
relative to one another when the second actuator adjusts the torque
tube.
5. The gas turbine system of claim 4, wherein the predetermined
ratio is approximately constant.
6. The gas turbine system of claim 1, wherein the first and second
motor controllers are respectively configured to control the first
and second actuators dependent on an operating mode of the gas
turbine system, and the operating mode comprises a startup mode or
a steady state mode.
7. A gas turbine system, comprising: a compressor having a
plurality of vanes disposed circumferentially about an axis of the
compressor; a first actuator configured to adjust a pitch of the
plurality of vanes; a second actuator configured to adjust the
pitch of the plurality of vanes; a first electric motor configured
to drive the first actuator; a second electric motor configured to
drive the second actuator; and a control system comprising the
first and second electric motors, wherein the control system is
configured to control the first and second actuators independently
in coordination with one another via first and second motor
controllers, respectively, and wherein the control system is
configured to control the first and second actuators based on a
first position feedback from the first actuator and a second
position feedback from the second actuator, and wherein the control
system is configured to control the first and second actuators
independently in coordination with one another, via the first and
second motor controllers, to help achieve a targeted flow and
pressure profile in the compressor.
8. The gas turbine system of claim 7, wherein the control system is
configured to transmit an input signal to the first motor
controller coupled to the first electric motor and the second motor
controller coupled to the second electric motor, wherein the input
signal is based on a desired pitch of the plurality of vanes.
9. The gas turbine system of claim 7, wherein the control system
comprises the first motor controller configured to receive the
first position feedback from the first actuator and the second
motor controller configured to receive the second position feedback
from the second actuator, and the control system is configured to
coordinate control of the first and second electric motors based on
the first and second position feedback.
10. The gas turbine system of claim 7, wherein the first and second
motor controllers are communicatively coupled to each other through
first and second serial links.
11. The gas turbine system of claim 7, wherein the first motor
controller is configured to receive the second position feedback
from the second motor controller, and wherein the first motor
controller is configured to send a first motor signal to the first
motor based on an input signal, the first position feedback, and
the second position feedback.
12. The gas turbine system of claim 7, wherein the first and second
motor controllers are configured to adjust the pitch of the
plurality vanes based on a predetermined shutdown sequence when
communication between the control system and the first or second
motor controllers is interrupted.
13. The gas turbine system of claim 7, comprising: a combustor
fluidly coupled with the compressor and configured to receive
compressed air from the compressor; and a turbine communicatively
coupled with the combustor and configured to receive combustion
products from the combustor.
14. The gas turbine system of claim 7, wherein the plurality of
vanes comprises a first plurality of inlet guide vanes, a second
plurality of variable stator vanes, or both.
15. The gas turbine system of claim 7, wherein the first and second
motor controllers are respectively configured to control the first
actuator in a manner dependent on control of the second actuator,
or control the second actuator in a manner dependent on control of
the first actuator.
16. An actuator system, comprising: a first electric motor; a
second electric motor a first actuator configured to be driven by
the first electric motor and to adjust a first pitch of a plurality
of inlet guide vanes of a compressor; a second actuator configured
to be driven by the second electric motor to adjust a second pitch
of a plurality of variable stator vanes; and at least one
controller comprising memory and a processor configured to execute
instructions to control the first electric motor and the second
electric motor based on sensor feedback relating to operation of
the compressor.
17. The actuator system of claim 16, wherein the instructions
comprise a software stop configured constrain axial movement of a
shaft of the first actuator within a range of movement.
18. The actuator system of claim 17, wherein the range of movement
is less than a length of the passage.
19. The actuator system of claim 16, wherein the at least one
controller comprises a first controller corresponding with the
first electric motor and a second controller corresponding with the
second electric motor, wherein the first controller and the second
controller are configured to control the first electric motor and
the second electric motor independently.
20. The actuator system of claim 19, wherein the first controller
and the second controller are communicatively coupled and
configured to coordinate to adjust the first pitch of the plurality
of inlet guide vanes and the second pitch of the plurality of
variable stator vanes.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/721,000, entitled "SYSTEM FOR TURBOMACHINE
VANE CONTROL" and filed on Dec. 19, 2012, which is hereby
incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] The subject matter disclosed herein relates to gas turbines,
and more specifically, to systems for controlling operation of the
gas turbine.
[0003] Gas turbine systems generally include a compressor, a
combustor, and a turbine. The compressor compresses air from an air
intake, and subsequently directs the compressed air to the
combustor. In the combustor, the compressed air received from the
compressor is mixed with a fuel and is combusted to create
combustion gases. The combustion gases are directed into the
turbine. In the turbine, the combustion gases pass across turbine
blades of the turbine, thereby driving the turbine blades, and a
shaft to which the turbine blades are attached, into rotation. The
rotation of the shaft may further drive a load, such as an
electrical generator, that is coupled to the shaft. Unfortunately,
the flow and pressure of the fluids into the compressor or turbine
may be unstable or unsuitable for particular operating modes of the
gas turbine system.
BRIEF DESCRIPTION OF THE INVENTION
[0004] Certain embodiments commensurate in scope with the
originally claimed invention are summarized below. These
embodiments are not intended to limit the scope of the claimed
invention, but rather these embodiments are intended only to
provide a brief summary of possible forms of the invention. Indeed,
the invention may encompass a variety of forms that may be similar
to or different from the embodiments set forth below.
[0005] In one embodiment, a gas turbine system includes a
compressor. The compressor has a plurality of inlet guide vanes
disposed at an inlet of the compressor. Furthermore, the compressor
may have at least one unison ring coupled to a plurality of
variable stator vanes disposed between the inlet and an outlet of
the compressor. The gas turbine system includes a first actuator
that may adjust a first pitch of the plurality of inlet guide vanes
and a second actuator that may adjust a second pitch of the
plurality of variable stator vanes. A first electric motor may
drive the first actuator, while a second electric motor may drive
the second actuator.
[0006] In a second embodiment, a gas turbine system includes a
compressor having a plurality of vanes disposed circumferentially
about an axis of the compressor. First and second actuators may
adjust a pitch of the plurality of vanes. A first electric motor
may drive the first actuator, and a second electric motor may drive
the second actuator. Furthermore, a first motor controller may
execute first instructions to control the first electric motor, and
a second motor controller may execute second instructions to
control the second electric motor.
[0007] In a third embodiment, an actuator system for a compressor
includes an electric motor, and an actuator that may be driven by
the electric motor. A controller includes memory and a processor
that may execute instructions to control the electric motor. The
actuator includes a housing and a shaft disposed within a passage
of the housing. The passage defines a first physical stop that may
constrain axial movement of the shaft. At least one frusto-conical
washer is disposed around the shaft. A spring is coupled to a
spring support defining a second physical stop that may constrain
axial movement of the shaft when the at least one frusto-conical
washer contacts the spring support.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0009] FIG. 1 is a schematic diagram of an embodiment of a gas
turbine system having a compressor equipped with vanes and an
actuation system with one or more electric actuators to control the
vanes;
[0010] FIG. 2 is a partial cross-sectional view of an embodiment of
the compressor of FIG. 1, illustrating inlet guide vanes (IGVs) and
multiple sets of variable stator vanes (VSVs) adjusted by the one
or more electric actuators;
[0011] FIG. 3 is front view of an embodiment of the compressor of
FIG. 1, illustrating multiple actuators adjusting a single set of
compressor vanes in coordination with one another;
[0012] FIG. 4 is a schematic diagram of an embodiment of the
actuation system of FIG. 1, illustrating a digital communication
link enabling communication between multiple motor controllers;
and
[0013] FIG. 5 is a cross-sectional view of an embodiment of the
actuator of FIG. 1 equipped with features to improve the
operability of the actuation system.
DETAILED DESCRIPTION OF THE INVENTION
[0014] One or more specific embodiments of the present invention
will be described below. In an effort to provide a concise
description of these embodiments, all features of an actual
implementation may not be described in the specification. It should
be appreciated that in the development of any such actual
implementation, as in any engineering or design project, numerous
implementation-specific decisions must be made to achieve the
developers' specific goals, such as compliance with system-related
and business-related constraints, which may vary from one
implementation to another. Moreover, it should be appreciated that
such a development effort might be complex and time consuming, but
would nevertheless be a routine undertaking of design, fabrication,
and manufacture for those of ordinary skill having the benefit of
this disclosure.
[0015] When introducing elements of various embodiments of the
present invention, the articles "a," "an," "the," and "said" are
intended to mean that there are one or more of the elements. The
terms "comprising," "including," and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
[0016] The present disclosure is directed toward systems to control
turbomachine vanes within gas turbine systems. In particular, a
compressor includes one or more compressor stages, each defined by
a set of rotor blades (e.g., blades rotating about the compressor
axis) and a set of stator vanes (e.g., stationary vanes). For
example, the stator vanes may include inlet guide vanes (IGVs)
positioned at an inlet of the compressor, variable stator vanes
(VSVs) positioned between the inlet and an outlet of the
compressor, or both. During or before operation of the compressor,
it may be desirable to adjust a pitch (e.g., angle relative to the
compressor axis) of the stator vanes in order to control certain
operating conditions of the compressor (e.g., flow rate or pressure
drop). It should be noted that the desired pitch of the compressor
vanes may vary depending on an operating mode of the gas turbine
(e.g., start-up, transient, steady-state, partial-load, or
full-load), as will be discussed in detail below. To this end,
electric actuators are coupled to the stator vanes in order to
adjust the pitch of the stator vanes. The electric actuators may be
driven by electric motors, which, in turn, are controlled by motor
controllers. Advantageously, electric actuators may be relatively
accurate compared to certain types of actuators (e.g., pneumatic
actuators or hydraulic actuators).
[0017] In certain embodiments, each set of stator vanes may be
adjusted by one or more electric actuators. That is, a single set
of stator vanes defined by an axial position may be coupled to 1,
2, 3, 4, or more electric actuators. In general, increasing the
number of electric actuators for a single set of stator vanes
increases the operability of the stator vanes. In embodiments with
2 or more electric actuators coupled to a single stage of vanes, it
may be desirable for the actuators and their associated equipment
(e.g., motors and motor controllers) to be in communication with
one another to improve the operability of the compressor vanes.
[0018] Turning now to the figures, FIG. 1 illustrates a block
diagram of an embodiment of a gas turbine system 10 having a
compressor 56 equipped with vanes 14 that may be adjusted by an
actuation system 16. Throughout the discussion, a set of axes will
be referenced. These axes are based on a cylindrical coordinate
system and point in an axial direction 18, a radial direction 20,
and a circumferential direction 22. For example, the axial
direction 18 extends along a longitudinal axis 24 of the gas
turbine system 10, the radial direction 20 extends away from the
longitudinal axis 24, and the circumferential direction 22 extends
around the longitudinal axis 24. Furthermore, it should be noted
that a variety of rotary equipment, such as compressors, turbines,
pumps, and/or the like, may benefit from the adjustable vanes 14
and the actuation system 16.
[0019] As shown, the compressor 56 includes multiple stages of the
vanes 14 disposed at various positions along the compressor 56 in
the axial direction 18. More specifically, the compressor 56
includes inlet guide vanes (IGVs) 26 (e.g., 14) positioned at an
inlet 28 of the compressor 56, variable stator vanes (VSVs) 30
(e.g., 14) disposed between the inlet 28 and an outlet 32 of the
compressor 56, and rotor blades 58 disposed between the IGVs 26 and
the VSVs 30. In general, the rotor blades 58 are coupled to a rotor
(e.g., shaft 36) of the compressor 56, and rotate about the
longitudinal axis 24 in the circumferential direction 22 during
operation of the compressor 56. On the other hand, IGVs 26 and VSVs
30 are coupled to stator (e.g., stationary) components of the
compressor 56, and generally do not rotate about the longitudinal
axis 24.
[0020] As illustrated, the actuator system 16 is coupled to each of
the IGVs 26 and the VSVs 30. However, in certain embodiments, the
actuation system 16 may be coupled to only a portion of the IGVs 26
and VSVs 30. In other words, a portion of the compressor vanes 14
may have a fixed pitch or angle, whereas another portion of the
compressor vanes 14 may have an adjustable pitch that is controlled
by the actuation system 16. As will be described in further detail
below, the actuation system 16 includes a first actuator 38 coupled
to the IGVs 26, a first motor 40 (e.g., electric motor) that may
drive the first actuator 38, and a controller 42 (e.g., motor
controller) that provides signals that control operation of the
first motor 40. In a similar manner, a second actuator 44 controls
each of the VSVs 30. For example, the second actuator 44 may adjust
a torque tube 46 (e.g., a structure that transmits radial forces
along the axial direction 18) that, in turn, adjusts each of the
VSVs 30. A second motor 48 may drive the second actuator 44, and
controller 50 governs operation of the second motor 48.
[0021] During operation of the gas turbine system 10, it may be
desirable to adjust the pitch of the IGVs 26 and the VSVs 30. For
example, a lower pitch of the IGVs 26 and the VSVs 30 may be more
desirable during start-up operation, when flow rates and pressures
are generally lower. In other words, a lower pitch at the IGVs 26
and the VSVs 30 may provide less resistance to flow as the IGVs 26
and the VSVs 30 are generally not aligned with the longitudinal
axis 24. In addition, adjusting the IGVs 26 and VSVs 30 may
counteract pressure and flow fluctuations that occur within the
compressor 56. The IGVs 26 and VSVs 30 increases the operability of
the compressor 56 and the gas turbine system 10. Operation of the
gas turbine system 10 is summarized below.
[0022] An oxidant 52 flows from an intake 54 into the compressor
56, where the rotation of the compressor blades 58 compresses and
pressurizes the oxidant 52. The oxidant 52 may include ambient air,
pure oxygen, oxygen-enriched air, oxygen-reduced air,
oxygen-nitrogen mixtures, or any suitable oxidant that facilitates
combustion of fuel. The following discussion refers to air 52 as an
example of the oxidant, but is intended only as a non-limiting
example. The air 52 flows into a fuel nozzle 60. Within the fuel
nozzle 60, fuel 62 mixes with the air 52 at a ratio suitable for
combustion, emissions, fuel consumption, power output, and the
like. Thereafter, a mixture of the fuel 62 and the air 52 is
combusted into hot combustion products 64 within a combustor 66.
The hot combustion products 64 enter the turbine 12 and force rotor
blades 34 to rotate, thereby driving the shaft 36 into rotation.
The rotating shaft 36 provides the energy for the compressor 56 to
compress the air 52. More specifically, the rotating shaft 52
rotates the compressor blades 58 attached to the shaft 36 within
the compressor 56, thereby pressurizing the air 52 that is fed to
the combustor 66. Furthermore, the rotating shaft 36 may drive a
load 68, such as an electrical generator or any other device
capable of utilizing the mechanical energy of the shaft 36. After
the turbine 12 extracts useful work from the combustion products
64, the combustion products 64 are discharged to an exhaust 70.
[0023] FIG. 2 illustrates a partial cross-sectional view of an
embodiment of the compressor 56, showing the IGVs 26 and the VSVs
30 in greater detail. Again, it should be noted that the adjustable
vanes 14 may be applied to a variety of rotating equipment, such as
the compressor 56, the turbine 12, or any combination thereof. As
shown, the IGVs 26 are coupled to a first unison ring 72 and are
positioned with a first pitch 74. The actuator 38 may move the
first unison ring 72 (e.g., in the radial 20 or circumferential 22
direction), thereby moving each of the IGVs 26 in the radial 20 or
circumferential 22 direction. In certain embodiments, each of the
IGVs 26 may be positioned at a substantially similar pitch. In a
similar manner, first, second, and third stages 76, 78, and 80 of
the VSVs 30 are coupled to respective unison rings 82, 84, and 86.
The actuator 44 may move the torque tube 46 (e.g., in the radial 20
or circumferential 22 direction) in order to adjust each of the
unison rings 82, 84, and 86 in the radial 20 or circumferential 22
direction, thereby adjusting respective pitches 88, 90, and 92 of
the VSV stages 76, 78, and 80. As noted earlier, the compressor 56
may include any suitable number of VSV stages. For example, the
compressor may be a single-stage compressor having a single VSV
stage, a dual-stage compressor having two VSV stages, or a
multi-stage compressor having 3, 4, 5, or more VSV stages.
[0024] Because the pitches 88, 90, and 92 of the VSVs 30 are
adjusted collectively by the position of the torque tube 46, it may
be desirable for the pitches 88, 90, and 92 to move in a
predetermined ratio relative to one another. That is, a certain
position of the torque tube 46 may correspond to specific pitches
of the VSVs 30, and adjustment of an individual VSV pitch may
affect the other VSV pitches. For example, the pitches 88 and 90
may have a constant ratio relative to one another while the torque
tube 46 is adjusted. While the pitches 88 and 90 may change, their
ratio may remain approximately constant during operation of the gas
turbine system 10. Such a configuration enables relatively
predictable operation of the gas turbine system 10. It should be
noted, however, that certain embodiments may employ additional
actuators to enable each of the VSV pitches 88, 90, and 92 to be
adjusted independently of one another.
[0025] As shown, the IGVs 26 are adjusted by the first actuator 38
(e.g., via radial 20 or circumferential 22 movement of the first
unison ring 72), whereas the VSVs 30 are collectively adjusted by
the second actuator 44 (e.g., via radial 20 or circumferential 22
movement the torque tube 46). This configuration enables the first
pitch 74 of the IGVs 26 to be controlled separately and
independently of the VSV pitches 88, 90, and 92. For example,
during start-up operation, it may be desirable to adjust the first
pitch 74 of the IGVs 26 to throttle flow of the air 52 while
maintaining the VSV pitches 88, 90, and 92 approximately constant.
On the other hand, during steady-state or full-load operation, it
may be desirable to adjust the VSV pitches 88, 90, and 92, while
maintaining the first pitch 74 of the IGVs 26 approximately
constant to control the outlet pressure or pressure ratio of the
compressor 56. Thus, in certain configurations, the IGVs 26 may
have a greater influence on the flow rate of the air 52 through the
compressor 56, while the VSVs 30 may have a greater influence on
the pressure profile within the compressor 56. Simultaneously
controlling the IGVs 26 and VSVs 30 may enable a targeted flow and
pressure profile within the compressor 56.
[0026] Although the embodiments illustrated in FIGS. 1 and 2 show a
single actuator (e.g., 38 or 44) coupled to each unison ring (e.g.,
72, 82, 84, and 86), multiple actuators may be coupled to each
unison ring to improve the stability and operability of the unison
rings. In general, 1, 2, 3, 4, or more actuators may be coupled
directly or indirectly (e.g., through the torque tube 46) to each
unison ring. As shown in FIG. 3, the unison rings may be coupled to
two or more actuators spaced circumferentially 22 about the
compressor 56.
[0027] FIG. 3 illustrates a front view of an embodiment of the
compressor 56 including multiple IGV actuators 94 and 96 (e.g., 38)
coupled to the unison ring 72 of the IGVs 26 and multiple VSV
actuators 98 and 100 (e.g., 44) coupled to the unison ring 82 of
the VSVs 30. The IGV actuators 94 and 96 are driven by respective
motors 102 and 104 (e.g., 40), whereas the VSV actuators 98 and 100
are driven by motors 106 and 108 (e.g., 48). Each set of actuators
(e.g., 94 and 96, 98 and 100) is spaced circumferentially 22 about
the longitudinal axis 24 of the compressor 56, which enables a
relatively uniform movement of the unison rings 72 and 82. It
should be noted that other arrangements of the actuators 94, 96,
98, and 100, may be envisioned, depending on the physical or
spatial limitations of the compressor 56. Furthermore, in
embodiments with more than one actuator, it may be desirable for
the multiple actuators and/or associated components (e.g.,
controller or motor) to be in communication with each other,
thereby improving the operability of the actuation system 16, as
discussed below with respect to FIG. 4.
[0028] FIG. 4 illustrates an embodiment of the actuation system 16
equipped with the multiple IGV actuators 94 and 96 coupled to the
single unison ring 72. Although the discussion is directed towards
the IGVs 26, it should be noted that the disclosed techniques may
also be applied to the VSVs 30 or any other vanes 14 with a
variable pitch. In other words, the ensuing discussion is generic
to the vanes 14 and may be applied to the IGVs 26, the VSVs 30, or
any combination thereof.
[0029] As shown, a control system 110 (e.g., distributed control
system) transmits an input signal 112 to motor controllers 114 and
116 (e.g., 42). The signal may be indicative of a desired pitch of
the IGVs 26, which, in turn, may be based on the current operating
conditions (e.g., pressure or flow rate) of the gas turbine system
10. As noted earlier, the pitch of the IGVs 26 may affect the
pressure and/or flow rate of the air 52 flowing through the
compressor 56. Accordingly, it may be desirable to adjust the pitch
74 of the IGVs 26 based on these operating conditions.
[0030] The motor controllers 114 and 116 transmit output signals
118 and 120 to the respective motors 102 and 104. The output
signals 118 and 120 may control the speed, torque, or other
operating conditions associated with the motors 102 and 104.
Although the motor controllers 114 and 116 and the motors 102 and
104 are illustrated as separate elements, in certain embodiments,
the motor controllers 114 and 116 may be included as motor drives
within the respective motors 102 and 104. That is, the motor
controllers 114 and 116 may be internal components of the motors
102 and 104.
[0031] As explained previously, operation of the motors 102 and 104
drives the actuators 94 and 96, thereby adjusting the IGVs 26. The
output signals 118 and 120 transmitted by the motor controllers 114
and 116 may be based on the input signal 112 and/or positional
feedback from the actuators 94 and 96 via feedback lines 122 and
124. That is, the output signals 118 and 120 may be based on the
desired IGV position as well as the current IGV position.
Furthermore, the output signals 118 and 120 may be coordinated with
each other. Because both actuators 94 and 96 jointly move the
unison ring 72, it may be desirable for each motor controller 112
and 114 to be informed of the actions and signals transmitted by
the other controller. In other words, the output signal 118 may be
based on the output signal 120, and vice versa. To this end, the
motor controllers 114 and 116 are communicatively coupled to each
other via serial links 126 and 128. The serial links 126 and 128
may include, for example, a wired connection, a wireless
connection, or both. The serial links 126 and 128 enable controlled
adjustment of the IGVs 26 by enabling communication between the
motor controllers 114 and 116.
[0032] As shown, each of the motor controllers 114 and 116 includes
respective processors 130 and 132 and memory 134 and 136 to execute
instructions to control the corresponding motors and actuators in
order to adjust the IGVs 26. For example, the processors 130 and
132 may include general-purpose or application-specific
microprocessors. In some embodiments, the motor controllers 114 and
116 may include an application-specific or general purpose
computer. The instructions (e.g., software or hardware
instructions) may be encoded in software programs that may be
executed by the processor 130 and 132. Further, the instructions
may be stored in a tangible, non-transitory, computer-readable
medium, such as the memory 134 and 136. The memory 134 and 136 may
include, for example, random-access memory, read-only memory, hard
drives, and/or the like. The motor controllers 114 and 116 may
interact with the motors 102 and 104, the actuators 94 and 96, and
the control system 110 in order to improve the operability of the
gas turbine system 10.
[0033] By way of example, shutdown instructions for the gas turbine
system 10 may be stored within the memory 134 and 136. If
communication between the control system 110 and the motor
controllers 114 and 116 is interrupted, or the gas turbine system
10 enters a shutdown mode for any other reason, it may be desirable
to gradually adjust the IGVs 26 to a suitable pitch for shutdown.
The motor controllers 114 and 116 may transmit predetermined
signals to the motors 102 and 104 based on the instructions stored
within the memory 134 and 136. However, the serial links 126 and
128, which are external of the control system 110, enable the motor
controllers 114 and 116 to remain in communication with one
another, even when communication with the control system 110 is
interrupted. Thus, the output signals 118 and 120 may be based on
the positional feedback 122 and 124, as well as the instructions
stored within the memory 134 and 136. Such a configuration reduces
the possibility that the motors 102 and 104 and the actuators 94
and 96 are out of sync with one another, thereby improving the
operability of the gas turbine system 10. It should be appreciated
that the memory 134 and 136 may store predetermined instructions
for a wide range of operating modes, including start-up, standby,
shutdown, partial-load, full-load, transient, steady-state, or any
other suitable operating mode.
[0034] FIG. 5 illustrates a cross-sectional view of an embodiment
of an actuator 138 (e.g., 38 or 44) that may be used to actuate the
IGVs 26, the VSVs 30, or both. As shown, a drive system 139 is
coupled directly to the actuator 138. The drive system may include
a motor 140 (e.g., 40 or 48) as well as a system of gears, belts,
drive shafts, and the like in order to actuate the IGVs 26 and the
VSVs 30. An external motor controller 141 (e.g., 42 or 50) is
communicatively coupled to the motor 140. Operation of the motor
140 drives a shaft 146 of the actuator 138 into rotation. Rotation
of the shaft 146 results in movement of the shaft 146 along the
axial direction 18. Movement of the shaft 146 adjusts the unison
rings, and subsequently, the pitch of the blades 14. The shaft 146
defines an axis 148 of the actuator 138. Within FIG. 5, the terms
axial 18, radial 20, and circumferential 22 are relative to the
axis 148. That is, the axial 18 direction is taken along the axis
148, the radial 20 direction points away from the axis 148, and the
circumferential 22 direction travels around the axis 148.
[0035] As shown, a support bearing 150 is coupled circumferentially
22 about the shaft 146. The support bearing 150 supports axial 18
loading of the shaft 146. The shaft 146 is disposed within a
passage 152 of an actuator housing 154. The passage 152 generally
defines axial 18 movement limits (e.g., a physical stop or
limitation) of the shaft 146. That is, the shaft 146 is
substantially constrained between opposite axial ends 154 and 156
of the passage 152. These movement limits 154 and 156 may
correspond to an acceptable range of pitches for the IGVs 26, the
VSVs 30, or both. Furthermore, the ranges may vary depending based
on the type of vane 14. For example, the opposite axial ends 154
and 156 may correspond to a pitch range of approximately 0 to 50,
10 to 40, or 20 to 30 degrees for the IGVs 26 or to a pitch range
of approximately 20 to 40, 10 to 50, or 0 to 60 degrees for the
VSVs 30. In certain embodiments, it may be desirable for the IGVs
26 to entirely close to block flow, while not entirely closing the
VSVs. In summary, the pitch range, as well as a length of the shaft
146, a length of the passage 152, or any combination thereof, may
be designed based on the type of compressor vane 14 adjusted by the
actuator 138.
[0036] The actuator 138 may also include a spring 158 supported by
a spring support 160. Furthermore, one or more washers 162 (e.g.,
Belleville washers) having frusto-conical shapes are disposed
circumferentially about the shaft 146. Movement of the shaft 146
may result in contact between the washer 162 and the spring support
160. When the one or more washers 162 contacts the spring support
160, additional axial 18 movement of the shaft 146 is dampened by
the spring 158. That is, the spring 158 slows axial 18 movement of
the shaft 146 as the shaft 146 approaches the end 154 of the
passage 152. Such a configuration reduces the possibility of
over-rotation or over-extension of the shaft 146. Thus, the spring
158, spring support 160, and washer 162 may define an additional
physical stop or limitation for axial 18 movement of the shaft
146.
[0037] Although a single washer 162 is illustrated, any number
and/or configuration or washers may be used. For example, the
actuator 138 may exclude the spring 158, the spring support 160,
and the washer 162. Alternatively, the actuator may include 1, 2,
3, 4 or more washers 162. It should be appreciated that multiple
washers coupled together axially 18 may behave as a spring. The
orientation of the washers 162 (e.g., stacking in the same or
alternating direction) may be adjusted in order to adjust a spring
constant of the multiple washers 162. Furthermore, the desired
spring constant of the washers 162 may be based on the spring
constant of the spring 158. For example, it may be desirable for
the multiple washers 162 to be stiffer than the spring 158 in order
to improve the operability of the actuator 138.
[0038] Software stops may be used independently or in conjunction
with the physical stops described above. For example, a software
stop encoded within memory 164 and implemented by a processor 166
of the motor controller 141 may reduce rotation of the rotor 142
when certain thresholds are reached. For example, the motor
controller 141 may cease to rotate the rotor 142 when a pitch of
the vanes 14, a position of the shaft 146, a temperature, pressure,
or flow rate within the gas turbine system 10, or another operating
condition, or any combination thereof, reaches one or more
thresholds (e.g., is outside an acceptable range). As will be
appreciated, the operating condition may be detected as a
percentage of a span of a sensor (e.g., 0 to 100 percent), and the
software stops may be based on the span. For example, a software
stop may exist at or below approximately 30% of the span, and/or
above approximately 70% of the span. These software stops may be
implemented based on a variety of operating conditions and modes of
the gas turbine system 10. For example, a software stop on the IGV
pitch 74 may be different when the gas turbine system 10 is
operating in a start-up mode as compared to a steady-state mode.
Furthermore, certain embodiments may include bypasses for the
software stops described above.
[0039] Technical effects of the disclosed embodiments include
systems and control of the compressor vanes 14 within the gas
turbine system 10. During operation of the compressor 56, the pitch
of the IGVs 26, the VSVs 30, or both, are adjusted in order to
control certain operating conditions of the compressor 56 (e.g.,
flow rate or pressure drop). The desired pitch of the vanes 14 may
vary depending on an operating mode of the compressor 56 (e.g.,
start-up, transient, steady-state, partial-load, or full-load). The
pitch of the compressor vanes 14 is adjusted by the actuators 38
and 44 driven by the motors 40 and 48, which, in turn, are
controlled by the motor controllers 42 and 50.
[0040] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
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