BACKGROUND
[0001] The subject matter disclosed herein relates to a distributed gas turbine
engine control system.
[0002] Gas turbine systems typically employ an engine controller, such as a full
authority digital engine controller (FADEC), to control various parameters associated
with operation of the gas turbine system. For example, the engine controller may be
configured to receive an input signal (e.g., indicative of throttle setting, desired he1
mixture, etc.) from a remote network, and to adjust various operational parameters of
the gas turbine system based on the input signal. By way of example, if the controller
receives an input signal indicative of a desired throttle setting, the engine controller
may rotate compressor vanes to a desired angle, adjust positions of fuel valves, andlor
adjust cooling air flow to turbine blades to establish the desired throttle setting.
[0003] Certain engine controllers utilize a first control loop to compute target
values of the operational parameters based on the input signal, and a second control
loop to adjust the operational parameters based on the target values. To facilitate
control of the operational parameters, multiple actuators may be communicatively
coupled to the engine controller. In addition, sensors may be communicatively
coupled to the engine controller to provide feedback signals indicative of measured
values of the operational parameters, thereby enabling the engine controller to provide
closed-loop control of the actuators. In certain embodiments, the sensors may be
disposed within a housing of the engine controller, and a lineltube may extend
between each sensor and a respective component associated with the parameter. For
example, the engine controller may be configured to control compressor exit pressure
by adjusting a valve position based on a measured compressor exit pressure.
Accordingly, a tube may extend from a pressure tap to an electronic pressure
transducer within the engine controller. In this configuration, the engine controller
may monitor compressor exit pressure based on feedback from the electronic
transducer, and adjust the position of the valve until the measured pressure is
substantially equal to a desired pressure.
[0004] As the number of controlled parameters within the gas turbine system
increases, the number of sensors within the engine controller, and the corresponding
number of linesltubes also increase. The increased number of sensors may increase
the size of the engine controller housing, thereby increasing the difficulty associated
with mounting the engine controller within an engine nacelle. In addition, the
increased number of linesltube may increase the weight of the engine control system,
thereby reducing vehicle performance. Moreover, because the sensors within the
engine controller are selected to measure parameters associated with a particular
engine configuration, modifying the engine configuration (e.g., varying the number
andlor type of controlled parameters) may prompt a redesign and recertification of the
engine controller. Accordingly, the duration and costs associated with engine
development may be undesirably increased.
BRIEF DESCRIPTION
[0005] In one embodiment, a gas turbine engine control system includes an engine
controller configured to control multiple parameters associated with operation of a gas
turbine engine system. The gas turbine engine control system also includes multiple
remote interface units communicatively coupled to the engine controller. The remote
interface unit is configured to receive an input signal from the engine controller
indicative of respective target values of at least one parameter, and the remote
interface unit is configured to provide closed-loop control of the at least one
parameter based on the input signal and feedback signals indicative of respective
measured values of the at least one parameter.
[0006] In another embodiment, a gas turbine engine control system includes
multiple remote interface units distributed throughout a gas turbine engine system.
The remote interface unit includes an actuator configured to adjust a respective
parameter associated with operation of the gas turbine engine system, a sensor
configured to output a feedback signal indicative of a measured value of the
respective parameter, and an interface controller communicatively coupled to the
actuator and to the sensor. The interface controller is configured to provide closedloop
control of the actuator based on the feedback signal. The gas turbine engine
control system also includes an engine controller communicatively coupled to the
remote interface unit. The engine controller is configured to instruct the interface
controller to establish a target value of the respective parameter.
[0007] In a further embodiment, a gas turbine engine control system includes an
engine controller configured to control multiple parameters associated with operation
of a gas turbine engine system. The gas turbine engine control system also includes
multiple remote interface units communicatively coupled to the engine controller. At
least one remote interface unit includes at least one local loop closure module having
an interface controller. The at least one remote interface unit also includes an actuator
communicatively coupled to the interface controller, and configured to adjust one
parameter. In addition, the at least one remote interface unit includes a sensor
communicatively coupled to the interface controller, and configured to output a
feedback signal indicative of a measured value of the one parameter. The interface
controller is configured to provide closed-loop control of the actuator based on the
feedback signal and an input signal from the engine controller indicative of a target
value of the one parameter.
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 block diagram of an embodiment of a turbine system including a
distributed control system configured to adjust various operational parameters of the
turbine system via multiple remote interface units distributed throughout the turbine
system;
[0010] FIG. 2 is a block diagram of an embodiment of a distributed control system
that may be employed within the turbine system of FIG. 1 ;
[0011] FIG. 3 is a block diagram of an embodiment of a remote interface unit that
may be employed within the distributed control system of FIG. 2; and
[0012] FIG. 4 is a block diagram of an alternative embodiment of a remote
interface unit that may be employed within the distributed control system of FIG. 2.
DETAILED DESCRIPTION
I00131 One or more specific embodiments 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 businessrelated
constraints, which may vary from one implementation to another. Moreover,
it should be appreciated that such a development effori 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.
[0014] When introducing elements of various embodiments disclosed herein, 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.
[0015] Embodiments disclosed herein may substantially reduce the weight and
complexity of an engine control system by distributing remote interface units
throughout a turbine system to provide local control of parameters associated with
operation of the turbine system. In certain embodiments, a gas turbine engine control
system includes an engine controller configured to control multiple parameters
associated with operation of the gas turbine engine system. The gas turbine engine
control system also includes multiple remote interface units communicatively coupled
to the engine controller. The remote interface unit is configured to receive an input
signal from the engine controller indicative of a target value of an operational
parameter. The remote interface unit is also configured to provide closed-loop control
of the operational parameter based on the input signal and a feedback signal indicative
of a measured value of the operational parameter. The remote interface units may be
distributed throughout the gas turbine engine system to control a variety of
operational parameters, such as valve positions, vane orientations, and fluid pressures,
among others. In certain embodiments, the remote interface unit includes an actuator
configured to adjust the operational parameter, and a sensor configured to output the
feedback signal.
[0016] Because the remote interface units provide local control of the operational
parameters, the weight and complexity of the engine control system may be
substantially reduced, as compared to configurations in which the engine controller
directly controls the operational parameters. For example, because the sensors are
communicatively coupled to local remote interface units, linesltubes extending
between components associated with each parameter and sensors mounted within the
engine controller are obviated, thereby reducing the weight of the engine control
system. In addition, because the sensors are not disposed within the engine controller,
the size of the engine controller may be reduced, thereby facilitating engine controller
mounting within an engine nacelle. Furthermore, the number of controlled
parameters may be adjusted by varying the number of remote interface units and/or
the number of actuatorslsensors within each remote interface unit. Accordingly, a
single engine controller configuration may be employed to control operation of a
variety of engine configurations (e.g., having different numbers and/or types of
operational parameters), thereby obviating the process of redesigning and recertifying
the engine controller for each engine configuration. As a result, engine development
costs may be significantly reduced.
[0017] Turning now to the drawings, FIG. 1 is a block diagram of an embodiment
of a turbine system including a distributed control system configured to adjust various
operational parameters of the turbine system via multiple remote interface units
distributed throughout the turbine system. While a turbine system is described below,
it should be appreciated that the distributed control system may be utilized to adjust
operational parameters within other rotary machines or turbo machines, such as a
compressor, a jet engine, a pump, or a steam turbine, for example. The illustrated
turbine system 10 includes a fuel injector 12, a fuel supply 14, and a combustor 16.
As illustrated, the fuel supply 14 routes a liquid fuel andlor gas fuel, such as natural
gas, to the gas turbine system 10 through the fuel injector 12 into the combustor 16.
As discussed below, the fuel injector 12 is configured to inject and mix the fuel with
compressed air. The combustor 16 ignites and combusts the fuel-air mixture, and
then passes hot pressurized gas into a turbine 18. As will be appreciated, the turbine
18 includes one or more stators having fixed vanes or blades, and one or more rotors
having blades which rotate relative to the stators. The hot gas passes through the
turbine rotor blades, thereby driving the turbine rotor to rotate. Coupling between the
turbine rotor and a shaft 19 causes rotation of the shaft 19, which is also coupled to
several components throughout the gas turbine system 10, as illustrated. Eventually,
the gas exits the gas turbine system 10 via an exhaust outlet 20.
[0018] A compressor 22 includes blades rigidly mounted to a rotor which is driven
to rotate by the shaft 19. As air passes through the rotating blades, air pressure
increases, thereby providing the combustor 16 with sufficient air for proper
combustion. The compressor 22 intakes air to the gas turbine system 10 via an air
intake 24. Further, the shaft 19 may be coupled to a load 26, which may be powered
via rotation of the shaft 19. As will be appreciated, the load 26 may be any suitable
device that may use the power of the rotational output of the gas turbine system 10,
such as a power generation plant or an external mechanical load. For example, the
load 26 may include an electrical generator, a propeller of an airplane, and so forth.
The air intake 24 draws air 30 into the gas turbine system 10 via a suitable
mechanism, such as a cold air intake. The air 30 then flows through blades of the
compressor 22, which provides compressed air 32 to the combustor 16. In particular,
the fuel injector 12 may inject the compressed air 32 and fuel 14, as a fuel-air mixture
34, into the combustor 16. Alternatively, the compressed air 32 and fuel 14 may be
injected directly into the combustor for mixing and combustion.
[0019] As illustrated, the turbine system 10 includes a distributed engine control
system 36 having an engine controller 38, and multiple remote interface units (RIU)
40 distributed throughout the turbine system 10. The engine controller 38 is
configured to control multiple parameters associated with operation of the turbine
system 10. For example, the engine controller may be configured to receive
instructions from a remote network, and to control the operational parameters of the
turbine system 10 based on the instructions. By way of example, if the engine
controller 38 receives instructions to establish a desired throttle setting, the engine
controller 38 may send signals to the remote interface units 40, instructing the remote
interface units 40 to adjust various operational parameters of the turbine system 10 to
achieve the desired throttle setting. For example, the engine controller 38 may
instruct the remote interface unit 40 coupled to the compressor 22 to adjust a
compressor vane angle. The engine controller 38 may also instruct the remote
interface unit 40 coupled to the combustor 16 to open valves that provide increased
fuel flow to the combustor 16. In addition, the engine controller 38 may instruct the
remote interface unit 40 coupled to the turbine 18 to open valves that provide
additional cooling air flow to the turbine blades. In this manner, a desired throttle
setting may be achieved while maintaining turbine system efficiency. In the
illustrated embodiment, the engine controller 38 is configured to receive instructions
from a flight control system of an aircraft. However, it should be appreciated that the
engine controller 38 may receive instructions from a ground-based control network, or
any other suitable system configured to provide instructions to the engine controller
38.
[0020] Each remote interface unit 40 within the turbine system 10 is
communicatively coupled to the engine controller 38, and configured to receive an
input signal from the engine controller 38 indicative of a target value of an operational
parameter. For example, the engine controller 38 may send an input signal to the
remote interface unit 40 coupled to the compressor 22 indicative of a target vane
angle. Similarly, the engine controller 38 may send an input signal to the remote
interface unit 40 coupled to the combustor 16 indicative of a fuel valve position. Each
remote interface unit 40, in turn, is configured to provide closed-loop control of the
operational parameter based on the input signal and a feedback signal indicative of a
measured value of the parameter. Accordingly, if the engine controller 38 instructs
the remote interface unit 40 coupled to the compressor 22 to rotate the compressor
vanes to a target angle, the remote interface unit 40 may instruct an actuator to rotate
the vanes to the target angle based on a feedback signal from a sensor configured to
measure the vane angle. Furthermore, if the engine controller 38 instructs the remote
interface unit 40 coupled to the combustor 16 to set a fuel valve to a target position,
the remote interface unit 40 may instruct an actuator to adjust the valve to the target
position based on a feedback signal from a sensor configured to measure valve
position.
[0021] Certain remote interface units 40 include one or more local loop closure
modules (LLCM) 42 configured to independently provide closed-loop control of a
respective operational parameter. For example, in the illustrated embodiment, the
remote interface unit 40 coupled to the compressor 22 includes two local loop closure
modules 42. As discussed in detail below, each local loop closure module 42 includes
an interface controller configured to provide closed-loop control of an actuator based
on a feedback signal from a sensor and the input signal from the engine controller 38.
Each remote interface unit 40 may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more local
loop closure modules 42 to provide closed-loop control of a corresponding number of
operational parameters. Accordingly, each remote interface unit 40 may control
parameters associated with a component (e.g., compressor 22, combustor 16, turbine
18, etc.) coupled to the remote interface unit 40, thereby providing distributed control
of the turbine system 10.
[0022] An alternative embodiment of a remote interface unit 40 is coupled to the
combustor 16. The remote interface unit 40 includes a multiple local loop closure
module (MLLCM) 44 configured to provide closed-loop control of multiple
parameters associated with operation of the turbine system 10. As discussed in detail
below, the multiple local loop closure module 44 includes an interface controller
configured to provide closed-loop control of multiple actuators based on feedback
signals from multiple sensors. For example, the remote interface unit 40 may include
multiple actuators configured to adjust a respective set of operational parameters, and
multiple sensors configured to output a respective set of feedback signals. In such
embodiments, the interface controller of the multiple local loop closure module 44,
which is communicatively coupled to each actuator and to each sensor, is configured
to provide closed-loop control of the actuators based on the respective feedback
signals. In this manner, a single multiple local loop closure module 44 within the
remote interface unit 40 may control multiple operational parameters associated with
a component (e.g., compressor 22, combustor 16, turbine 18, etc.) of the turbine
system 10. While the illustrated remote interface unit 40 includes a single multiple
local loop closure module 44, it should be appreciated that additional local loop
closure modules and/or multiple local loop closure modules may be included in
alternative embodiments of the remote interface unit 40.
[0023] As illustrated, another embodiment of a remote interface unit 40 is coupled
to the turbine 18. The remote interface unit 40 includes two smart actuator assemblies
46. Each smart actuator assembly 46 includes an actuator configured to adjust an
operational parameter of the turbine system 10, and a sensor configured to output a
feedback signal indicative of a measured value of the operational parameter. Each
smart actuator assembly 46 also includes an interface controller configured to provide
closed-loop control of the actuator based on the feedback signal and the input signal
from the engine controller 38 indicative of the target value of the parameter. Certain
remote interface units 40 may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more smart
actuator assemblies 46 to provide closed-loop control of a corresponding number of
operational parameters. Other remote interface units 40 may include at least one
smart actuator assembly 46, at least one local loop closure module 44, and/or at least
one multiple local loop closure module 44.
[0024] While three remote interface units 40 are employed in the illustrated
embodiment, it should be appreciated that alternative engine control systems 36 may
employ more or fewer remote interface units 40. For example, in certain
embodiments, the engine control system 36 may include 1, 2, 3, 4, 5, 6, 7, or more
remote interface units distributed throughout the turbine system 10. Furthermore, it
should be appreciated that the remote interface units 40 may be mounted within a
variety of locations throughout the turbine system 10. For example, a remote
interface unit may be mounted on an exterior surface of the compressor 22, within a
core of the turbine 18, and/or between the turbine 18 and the combustor 16, for
example. In certain embodiments, each component of the remote interface unit may
be disposed within a single housing. Alternatively, sensors and/or actuators may be
mounted remote from the housing, and communicatively coupled to the interface
controller, which is disposed within the housing. For example, a remote interface unit
housing mounted on the exterior surface of the compressor 22 may be
communicatively coupled to a sensor mounted within the turbine core.
[0025] As previously discussed, each remote interface unit 40 includes a sensor
configured to measure an operational parameter. Because the sensors are not
disposed within the engine controller, lineltubes configured to convey
pressures/temperatures to the engine controller are obviated. Consequently, the
weight of the engine control system 36 may be reduced. In addition, the size of the
engine controller 38 may be reduced because the sensors are mounted within
respective remote interface units 40, thereby facilitating engine controller mounting
within an engine nacelle. Moreover, the engine controller 38 may be utilized to
control a variety of engine configurations by varying the type and/or number of
remote interface units communicatively coupled to the engine controller.
Accordingly, the process of redesigning and recertifying the engine controller for
varying engine configurations is obviated, which reduces turbine system development
costs.
[0026] FIG. 2 is a block diagram of an embodiment of a distributed control system
36 that may be employed within the turbine system 10 of FIG. 1. In the illustrated
embodiment, the engine controller 38 includes an engine control module 50
configured to control multiple parameters associated with operation of the turbine
system 10, and a power conditioning module 52 configured to provide electrical
power to the engine control module 50 and to the remote interface units 40. In certain
embodiments, the engine control module 50 and the power conditioning module 52
are disposed within independent housings positioned remote from one another.
Accordingly, the engine control module 50 may be thermally insulated from the heat
generated by the power conditioning module 52. The reduced heat flow to the engine
control module 50 may facilitate tighter spacing of electronic components, thereby
reducing the size of the engine controller 38. In addition, heat dissipation features,
such as cooling fins and/or an active fluid cooling system, may be obviated, thereby
reducing the cost and complexity of the engine controller 38.
[0027] In the illustrated embodiment, the power conditioning module 52 is
configured to provide electrical power to a first electrical bus 54 and a second
electrical bus 56. As will be appreciated, the first and second electrical busses 54 and
56 provide a redundant power distribution system that increases the availability of the
turbine system 10. As illustrated, the first and second electrical busses 54 and 56 are
electrically coupled to an ignition exciter 58. The ignition exciter 58 is configured to
generate a high voltage signal for a first igniter 60 and a second igniter 62. The
igniters are configured to initiate combustion within the combustor 16 during engine
startup procedures.
[0028] The electrical busses 54 and 56 are also electrically coupled to the remote
interface units 40 to provide redundant electrical power to the remote interface units
40. In addition, a first communication bus 64 and a second communication bus 66
extend between the engine control module 50 and each remote interface unit 40. The
communication busses 64 and 66 are configured to provide redundant signals between
the engine control module 50 and the remote interface units 40. In the illustrated
embodiment, one remote interface unit 40 includes two local loop closure modules 42
to provide redundant closed-loop control of an operational parameter. As illustrated,
the remote interface unit 40 is divided into a channel A section, and a channel B
section. Each channel is configured to independently control the same operational
parameter, thereby providing redundant control. As illustrated, the first electrical bus
54 is coupled to the channel A section, and the second electrical bus 56 is coupled to
the channel B section. Accordingly, if one channel is disabled due to an interruption
in electrical power, the other channel may continue operation. Similarly, the first
communication bus 64 is coupled to a communication module 68 in the channel A
section, and the second communication bus 66 is coupled to a communication module
68 in the channel B section. In this configuration, if one channel is disabled due to an
interruption in one communication bus, the other channel may continue operation.
[0029] Furthermore, the channel A section includes a first local loop closure
module 42 communicatively coupled to a first communication module 68, and the
channel B section includes a second local loop closure module 42 communicatively
coupled to a second communication module 68. The communication modules 68 are
configured to establish a communication link between an interface controller 70 in the
local loop closure module 42 and the respective communication bus. Consequently,
an input signal from the engine controller 38 may be sent to the local loop closure
module 42, and a return signal may be sent from the local loop closure module 42 to
the engine controller 38. For example, the input signal from the engine controller 38
may be indicative of a target value of an operational parameter. The return signal
may be indicative of a measured value of the operational parameter, and/or an
operational status of the local loop closure module 42. Accordingly, the engine
controller 38 may monitor the value of each operational parameter to determine
whether a parameter exceeds a threshold value, and/or to facilitate control of the
turbine system 10. In addition, the engine controller 38 may monitor the
healthloperational status of each component within the distributed engine control
system 36.
[0030] As will be appreciated, a variety of communication protocols may be
employed to establish a communication link between the communication modules 68
and the engine control module 50. For example, the first communication bus 64 and
the second communication bus 66 may utilize a balanced digital multipoint network
(e.g., RS-485) to facilitate communication throughout the distributed engine control
system 36. The communication buses 64 and 66 may also employ other wired or
wireless communication protocols. For example, if a wireless communication link is
employed, the reduced wiring may substantially reduce the weight and complexity of
the distributed engine control system 36. In certain embodiments, the communication
modules 68 may be configured to communicate with the engine control module 50 via
the electrical busses 54 and 56. For example, the engine control module 50 and the
communication modules 68 may be configured to modulate an electrical power signal
such that input and feedback signals may be transmitted throughout the distributed
engine control system 36, thereby obviating separate wired connections.
[0031] As previously discussed, each local loop closure module includes an
interface controller 70 configured to provide closed-loop control of a parameter
associated with operation of the turbine system 10. In addition, each channel of the
remote interface unit 40 includes a sensor 72 and an actuator 74 communicatively
coupled to a respective interface controller 70. The actuator 74 is configured to adjust
an operational parameter of the turbine system 10, the sensor 72 is configured to
output a feedback signal indicative of a measured value of the operational parameter,
and the interface controller 70 is configured to provide closed-loop control of the
actuator 74 based on the feedback signal and an input signal from the engine
controller 38 indicative of a target value of the operational parameter. In the
illustrated embodiment, the channel A actuator 74 and the channel B actuator 74 may
be configured to adjust the same operational parameter (e.g., compressor vane angle,
fuel valve position, cooling air valve position, etc.). Similarly, the channel A sensor
72 and the channel B sensor 72 may be configured to measure a value of the same
parameter. In certain embodiments, the channel A sensor 72 and the channel B sensor
72 may be disposed within a common housing andlor may include a common sensing
element. In such embodiments, separate conductors may extend from the common
housinglsensing element to each respective interface controller 70.
[0032] By way of example, the engine control module 50 may output a signal
indicative of a target value of an operational parameter to the channel A section of the
remote interface unit 40 via the first communication bus 64. The channel A
communication module 68 may receive the signal, and convey the target value to the
interface controller 70 within the channel A local loop closure module 42. The
controller 70, in turn, may instruct the actuator 74 to adjust the operational parameter
until the sensor 72 indicates that the target value is achieved. The interface controller
70 may then cyclically monitor the value of the parameter via a feedback signal from
the sensor 72, and instruct the actuator 74 to compensate for any variations from the
target value. In this manner, the channel A local loop closure module 42 may provide
closed-loop control of one parameter associated with operation of the turbine system
10.
[0033] It should be appreciated that a variety of actuators 74 may be employed
throughout the turbine system 10. For example, the turbine system 10 may include
mechanical, electromechanical, pneumatic and/or hydraulic linear actuators and/or
rotary actuators. Certain components of the turbine system 10 may be adjusted by a
two-element electro-hydraulic actuator that employs he1 as the working fluid. By
way of example, vanes within the compressor 22 may be coupled to a hydraulically
driven element of an electro-hydraulic actuator. The hydraulically driven element is
configured to adjust an angle of the vanes based on fuel pressure to the actuator
element. The electro-hydraulic actuator also includes a second element configured to
regulate fuel pressure to the hydraulically driven element. The second element may
be an electrically controlled (e.g., via a solenoid, stepper motor, etc.) valve
communicatively coupled to the interface controller 70. Accordingly, the interface
controller 70 may adjust the angle of the compressor vanes by regulating fuel pressure
to the hydraulically controlled element via actuation of the electrically controlled
element. In certain embodiments, the remote interface unit 40 may be disposed
within the hydraulically driven element (e.g., a fuel metering unit) to facilitate cooling
of electronic components within the interface controller 70, thereby increasing the
longevity of the remote interface unit 40.
[0034] In certain embodiments, the actuator 74 may be an electric torque motor,
and the sensor 72 may be a position sensor, such as a linear variable differential
transformer (LVDT). In such embodiments, the controller 70 may instruct the electric
torque motor to adjust an operational parameter until the position sensor indicates that
a target value is achieved (e.g., a component has been rotated through a desired angle,
a component has been translated a desired distance, etc.). The interface controller 70
may then cyclically monitor the value of the parameter via a feedback signal from the
position sensor, and instruct the electric torque motor to compensate for any
variations from the target value.
[0035] Similar to the communication busses 64 and 66, a variety of
communication protocols may be employed to establish a communication link
between the sensor 72 and the interface controller 70, and between the actuator 74 and
the interface controller 70. For example, the sensor 72 andlor the actuator 74 may be
communicatively coupled to the interface controller 70 by one or more conductors,
thereby facilitating transmission of analog or digital signals. As will be appreciated,
digital signals may be multiplexed, thereby enabling multiple signals (e.g., from one
or more sensors 72, andor from one or more actuators 74) to be transmitted through a
single bus. In addition, a wireless communication link may be employed to reduce
wiring.
[0036] In certain embodiments, the interface controller 70 is configured to monitor
the operational status of the local loop closure module 42. If an anomaly is detected
that may interfere with operation of the local loop closure module, the interface
controller 70 may instruct the communication module 68 to send a signal to the
engine control module 50 indicative of the anomaly. The engine control module 50
may then disable the channel A section of the remote interface unit 40, and instruct
the channel B section to control the operational parameter. Similarly, if electrical
power to the channel A section is disrupted andlor communication with the engine
control module 50 is interrupted, the engine control module 50 may disable the
channel A section of the remote interface unit 40, and enable the channel B section.
[0037] In certain embodiments, the channel A section and the channel B section of
the remote interface unit 40 may be operated concurrently. In such embodiments, a
communication link 76 between the interface controllers 76 may facilitate
communication between the local loop closure modules 42. For example, the channel
A sensor 72 and the channel B sensor 72 may concurrently measure the same
operational parameter. The interface controllers 70 may compare the measured values
to one another, and identify discrepancies. If a discrepancy is detected (e.g., the
difference between measured values exceeds a threshold value), the interface
controllers 70 may select the appropriate measurement andor report the discrepancy
to the engine control module 50 for analysislinterpretation. If the interface controllers
70 andor the engine control module 50 determine that one sensor 72 is not producing
accurate measurements, the interface controllers 70 andor the engine control module
50 may disable the respective channel of the remote interface unit 40, and instruct the
other channel to provide closed-loop control of the operational parameter.
[0038] In certain embodiments, each local loop closure module 42 is configured to
operate at a higher frequency than the engine control module 50. For example, the
interface controller 70 may be configured to receive a feedback signal from the sensor
72 and adjust the actuator 74 at a frequency of about 5 Hz, 10 Hz, 25 Hz, 50 Hz, 100
Hz or more. Conversely, the engine control module 50 may send a signal indicative
of a target value of an operational parameter to the remote interface unit at a
frequency of about 1 Hz, 2 Hz, or 3 Hz, for example. Due to the lower operational
frequency of the engine control module 50, less data is sent through the
communication busses 64 and 66, as compared to configurations in which a
centralized engine controller receives signals from the sensors and adjusts the
actuators at a higher frequency. Accordingly, a lower bandwidth network may be
employed, thereby reducing the cost of the engine control system.
[0039] While the illustrated remote interface unit 40 includes two channels
configured to control one operational parameter, it should be appreciated that
alternative remote interface units may include more or fewer channels to control one
or more parameters associated with operation of the turbine system. For example, in
certain embodiments, a remote interface unit 40 may include 1, 2, 3, 4, 5, 6, or more
channels to control one operational parameter. As previously discussed, more than
one channel provides redundant control of the operational parameter, thereby
increasing the availability of the turbine system 10. In addition, it should be
appreciated that certain remote interface units 40 may be configured to control
multiple operational parameters, with one or more channels associated with each
parameter. For example, certain remote interface units may be configured to control
1, 2, 3, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 50, or more parameters associated with
operation of the turbine system 10. By way of example, a remote interface unit may
be configured to control more than 1, 5, 10, 20, 30, 40, or more operational
parameters.
[0040] Moreover, while the illustrated remote interface unit 40 includes separate
communications modules 68 to establish a communication link between the engine
control module 50 and the respective local loop closure module 42, it should be
appreciated that certain remote interface units may include a single communication
module to facilitate communication between the engine control module 50 and each
local loop closure module 42. In further embodiments, a remote interface unit 40 may
include one communication module 68 for each local loop closure module associated
with a particular operational parameter. In addition, certain local loop closure
modules may include integrated communication modules, thereby obviating the
communication module within the remote interface unit.
[0041] Each remote interface unit 40 may be particularly configured for the
anticipated environmental conditions. For example, remote interface units positioned
within higher temperature portions of the turbine system may be configured to
effectively operate within the expected temperature range. For example, in low
temperature environments, such as adjacent to the compressor 22, the electric circuits
of the remote interface unit 40 may be mounted on a silicon substrate. In higher
temperature environments, such as adjacent to the combustor 16 or the turbine 18, the
electric circuits may be mounted on a silicon on insulator (SOI) substrate. For
example, an SO1 substrate may include an insulating layer (e.g., silicon dioxide)
disposed between two silicon layers. If the remote interface unit 40 is mounted within
the hottest regions of the turbine system 10, such as within the core of the turbine 18,
the electric circuits may be mounted on a silicon carbide substrate or a gallium nitride
substrate to resist the increased heat loads. In further embodiments, the remote
interface unit 40 may be actively cooled to facilitate operation in high temperature
environments. For example, fuel from the fuel supply 14 may pass through a heat
exchanger coupled to the remote interface unit 40 before flowing to the combustor 16,
thereby reducing the operating temperature of the remote interface unit 40.
[0042] Because the sensors are not disposed within the engine controller, the size
of the engine controller may be reduced, thereby facilitating engine controller
mounting within an engine nacelle. Furthermore, the number of controlled
parameters may be adjusted by varying the number of remote interface units andor
the number of actuators/sensors within each remote interface unit. Accordingly, a
single engine controller configuration may be employed to control operation of a
variety of engine configurations (e.g., having different numbers andlor types of
operational parameters), thereby obviating the process of redesigning and recertifying
the engine controller for each engine configuration. As a result, engine development
costs may be significantly reduced. In addition, the engine control system 36 may
utilize common remote interface unit configurations to control each parameter
associated with operation of the turbine system 10. In such a configuration, the
design and manufacturing costs may be further reduced by obviating the
designlcertification costs associated with development of multiple remote interface
unit configurations.
[0043] FIG. 3 is a block diagram of an embodiment of a remote interface unit 40
that may be employed within the distributed control system 36 of FIG. 2. As
illustrated, the remote interface unit 40 includes a smart actuator assembly 46 having
an integrated communication module 68, interface controller 70, sensor 72, and
actuator 74. Such a smart actuator assembly 46 may be employed to independently
control an operational parameter, or may be used in conjunction with one or more
similar smart actuator assemblies 46 to provide redundant control of a parameter (i.e.,
each smart actuator assembly 46 serves as a channel of a multichannel control
system). Remote interface units 40 having a smart actuator assembly 46 may be
distributed throughout the turbine system 10 to control parameters proximate to the
unit. For example, one remote interface unit 40 may be positioned adjacent to the
vanes of the compressor 22 to control an angle of the vanes, and another remote
interface unit 40 may be positioned adjacent to a fuel value to control fuel flow to the
combustor 16. By distributing the remote interface units throughout the turbine
system, the weight and complexity of the engine control system may be reduced by
obviating linesltubes, which may be employed in configurations having sensors
disposed within the engine controller.
[0044] While the illustrated remote interface unit 40 includes a single smart
actuator assembly 46, it should be appreciated that alternative remote interface units
may include additional smart actuator assemblies (e.g., 1, 2, 3, 4, 5, 6, or more).
Furthermore, it should be appreciated that certain remote interface units may include a
smart actuator assembly 46, and a local loop closure module 42 having a separate
sensor and a separate actuator. In addition, while the illustrated smart actuator
assembly 46 includes an integrated communication module 68, it should be
appreciated that alternative embodiments may employ a remote communication
module 68 (e.g., configured to establish a communication link with multiple smart
actuator assemblies 46). Moreover, while the illustrated smart actuator assembly 46
includes an integrated sensor 72, it should be appreciated that alternative
embodiments may employ a remote sensor 72 to measure the value of a parameter
remote from the actuator 74.
[0045] FIG. 4 is a block diagram of an alternative embodiment of a remote
interface unit 40 that may be employed within the distributed control system 36 of
FIG. 2. In the illustrated embodiment, the remote interface unit 40 includes a multiple
local loop closure module (MLLCM) 44 configured to provide closed-loop control of
multiple parameters associated with operation of the turbine system 10. As
illustrated, the multiple local loop closure module 44 includes an integrated
communication module 68 and an interface controller 70. However, it should be
appreciated that a remote communication module 68 may be employed in alternative
embodiments. The remote interface unit 40 also includes multiple actuators 74
communicatively coupled to the interface controller 70, and configured to adjust a
respective set of parameters associated with operation of the turbine system 10. In
addition, the remote interface unit 40 includes a corresponding set of sensors 72
communicatively coupled to the interface controller 70, and configured to output
respective feedback signals to the interface controller 70. The interface controller 70
is configured to provide closed-loop control of the actuators 74 based on the feedback
signals, and an input signal from the engine control module 50 (e.g., received through
the communication module 78) indicative of a target value of each parameter. In this
configuration, a single controller 70 within the remote interface unit 40 may control
multiple operational parameters associated with various components throughout the
turbine system 10.
[0046] While the illustrated embodiment includes four sensors 46 and four
actuators 44, it should be appreciated that alternative embodiments may include more
or fewer sensors/actuators. For example, certain remote interface units 40 may
include 1, 2, 3, 4, 5, 6, 7, 8, or more sensors 46, and a corresponding number of
actuators 44. In addition, certain parameters may be determined by measuring
multiple related parameters associated with operation of the turbine system 10. For
example, a velocity of a fluid flow may be determined by measuring a static pressure
and a dynamic pressure via two pressure sensors. Accordingly, the interface
controller 70 may be configured to determine a parameter based on feedback signals
from multiple sensors. The controller 70, in turn, may instruct an actuator to adjust
the parameter based on the determined value of the parameter.
[0047] 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.

CLAIMS:
1. A gas turbine engine control system, comprising:
an engine controller configured to control a plurality of parameters associated
with operation of a gas turbine engine system; and
a plurality of remote interface units communicatively coupled to the engine
controller, wherein the remote interface unit is configured to receive an input signal
from the engine controller indicative of respective target values of at least one
parameter of the plurality of parameters, and the remote interface unit is configured to
provide closed-loop control of the at least one parameter based on the input signal and
feedback signals indicative of respective measured values of the at least one
parameter.
2. The gas turbine engine control system of claim 1, wherein the remote
interface unit comprises an actuator configured to adjust the at least one parameter,
and a sensor configured to output the feedback signals.
3. The gas turbine engine control system of claim 1, wherein at least one
remote interface unit comprises a multiple local loop closure module configured to
provide closed-loop control of a respective set of the plurality of parameters.
4. The gas turbine engine control system of claim 1, wherein at least one
remote interface unit comprises a plurality of local loop closure modules, and the
local loop closure module is configured to independently provide closed-loop control
* of a respective parameter of the plurality of parameters.
5. The gas turbine engine control system of claim 4, wherein the local
loop closure module is configured to provide the closed-loop control of the respective
parameter by instructing an actuator to adjust the respective parameter based on the
feedback signals from a sensor.

6. The gas turbine engine control system of claim 4, wherein at least two
of the plurality of local loop closure modules are configured to provide redundant
closed-loop control of the at least one parameter.
7. The gas turbine engine control system of claim 1, wherein at least one
remote interface unit comprises a smart actuator assembly having an actuator
configured to adjust the at least one parameter, a sensor configured to output the
feedback signals, and an interface controller communicatively coupled to the actuator
and to the sensor, wherein the interface controller is configured to provide the closedloop
control of the at least one parameter.
8. The gas turbine engine control system of claim 1, wherein the remote
interface unit comprises a communication module configured to receive the input
signal from the engine controller.
9. The gas turbine engine control system of claim 1, wherein the engine
controller comprises an engine control module configured to control the plurality of
parameters, and a power conditioning module configured to provide electrical power
to the engine control module and to the plurality of remote interface units, wherein the
engine control module and the power conditioning module are disposed within
independent housings positioned remote from one another.
10. The gas turbine engine control system of claim 1, wherein the plurality
of remote interface units are distributed throughout the gas turbine engine system.
11. A gas turbine engine control system, comprising:
a plurality of remote interface units distributed throughout a gas turbine engine
system, wherein the remote interface unit comprises an actuator configured to adjust a
respective parameter associated with operation of the gas turbine engine system, a
sensor configured to output a feedback signal indicative of a measured value of the
respective parameter, and an interface controller communicatively coupled to the

actuator and to the sensor, wherein the interface controller is configured to provide
closed-loop control of the actuator based on the feedback signal; and
an engine controller communicatively coupled to the remote interface unit,
wherein the engine controller is configured to instruct the interface controller to
establish a target value of the respective parameter.
12. The gas turbine engine control system of claim 11, wherein at least one
remote interface unit comprises a smart actuator assembly, and the actuator, the
sensor, and the interface controller are disposed within the smart actuator assembly.
13. The gas turbine engine control system of claim 12, wherein at least one
remote interface unit comprises a plurality of local loop closure modules, and the
local loop closure module comprises a respective interface controller configured to
provide closed-loop control of a corresponding parameter.
14. The gas turbine engine control system of claim 11, wherein at least one
remote interface unit comprises a multiple local loop closure module having the
interface controller, a plurality of actuators configured to adjust a respective plurality
of parameters, and a corresponding plurality of sensors configured to output a
respective plurality of feedback signals, wherein the interface controller is configured
to provide closed-loop control of the plurality of actuators based on the respective
plurality of feedback signals.
15. The gas turbine engine control system of claim 11, wherein the engine
controller comprises an engine control module configured to instruct the interface
controller, and a power conditioning module configured to provide electrical power to
the engine control module and to the plurality of remote interface units, wherein the
engine control module and the power conditioning module are disposed within
independent housings positioned remote from one another.
24
16. A gas turbine engine control system, comprising:
an engine controller configured to control a plurality of parameters associated
with operation of a gas turbine engine system; and
a plurality of remote interface units communicatively coupled to the engine
controller, wherein at least one remote interface unit comprises:
at least one local loop closure module having an interface controller;
an actuator communicatively coupled to the interface controller, and
configured to adjust one parameter of the plurality of parameters; and
a sensor communicatively coupled to the interface controller, and
configured to output a feedback signal indicative of a measured value of the one
parameter;
wherein the interface controller is configured to provide closed-loop
control of the actuator based on the feedback signal and an input signal from the
engine controller indicative of a target value of the one parameter.
17. The gas turbine engine control system of claim 16, wherein the at least
one local loop closure module comprises a communication module configured to
receive the input signal from the engine controller.
18. The gas turbine engine control system of claim 16, wherein the at least
one remote interface unit comprises a plurality of local loop closure modules, and the
local loop closure module is configured to provide closed-loop control of a respective
parameter of the plurality of parameters.
19. The gas turbine engine control system of claim 18, wherein at least two
of the plurality of local loop closure modules are configured to provide redundant
closed-loop control of a single parameter.
20. The gas turbine engine control system of claim 16, wherein the
plurality of remote interface units are distributed throughout the gas turbine engine
system.

21. The gas turbine engine control system of claim 16, wherein the
actuator comprises an electric torque motor, and the sensor comprises a position
sensor.