Method and system for rotor stabilization

Abstract

A system and method for controlling rotor dynamics at a rotor assembly is provided. The system includes a magnetic actuator and a controller. The magnetic actuator is magnetically connected to the rotor assembly and obtains a measurement vector corresponding to the rotor assembly and a measurement vector indicating a rotor dynamic parameter. The magnetic actuator selectively outputs an electromagnetic force at the rotor assembly. The controller stores and executes instructions. The instructions include outputting a baseline electromagnetic force to the rotor assembly via the electromagnetic actuator; obtaining a measurement vector at the rotor assembly from the magnetic actuator; determining an asynchronous vibration corresponding to the rotor assembly based on at least the measurement vector and a rotor speed of the rotor assembly; determining a cross-coupling stiffness corresponding to the rotor assembly based on at least the measurement vector, the rotor speed and a predetermined rotor dynamic model of the rotor assembly; determining an adjusted electromagnetic force of the rotor assembly based on at least the cross-coupling stiffness and a damping factor corresponding to the electromagnetic force output from the magnetic actuator; and generating an output signal corresponding to the adjusted electromagnetic force to the rotor assembly.

Description

Technical Field

[0001] The present subject matter generally relates to damping systems and methods for rotor assemblies. The present subject matter more particularly relates to active damping systems and methods for turbines. Background Art

[0002] A damping system, such as a squeeze film damper at a bearing assembly of a turbine, can generally be targeted to a wide range of operating conditions of a rotor assembly of a turbine to which the damper system is attached. Such a damping system can be a passive system. Such a damping system may not be sufficient to provide damping or adequate damping at more targeted operating speeds or conditions. For example, such a wide frequency bandwidth damping system may not be sufficient to effectively provide damping with respect to rotor vortices, such as Alford vortices, or other undesirable rotor dynamic conditions, such as bowed rotor starting, clearance control, non-synchronous vibration (NSV), or general vibration suppression.

[0003] Therefore, there is a need for improved damping systems for rotor assemblies and turbines. Summary of the invention

[0004] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0005] A system and method for controlling a rotor assembly is provided. The system and method may include a system and method for mitigating undesirable rotor dynamics, rotor eddy currents, or vibrations from a rotor assembly. The system includes a magnetic actuator and a controller. The magnetic actuator is positioned in magnetic communication with the rotor assembly and is configured to obtain a measurement vector corresponding to the rotor assembly and a measurement vector indicating a rotor dynamic parameter. The magnetic actuator is also configured to selectively output an electromagnetic force at the rotor assembly. The controller is configured to store and execute instructions or one or more steps of the method. The method or instruction includes: outputting a baseline electromagnetic force to the rotor assembly via the magnetic actuator; obtaining a measurement vector at the rotor assembly from the magnetic actuator; determining an asynchronous vibration corresponding to the rotor assembly based on at least the measurement vector and a rotor speed of the rotor assembly; determining a cross-coupling stiffness corresponding to the rotor assembly based on at least the measurement vector, the rotor speed, and a predetermined rotor dynamic model of the rotor assembly; determining an adjusted electromagnetic force of the rotor assembly based on at least the cross-coupling stiffness and a damping factor corresponding to the electromagnetic force output from the magnetic actuator; generating an output signal corresponding to the adjusted electromagnetic force to the rotor assembly.

[0006] In one embodiment, determining the non-synchronous vibrations includes removing the synchronous vibration signals via a Fourier transform function.

[0007] In another embodiment, determining the cross-coupling stiffness is further based on at least a predetermined rotor dynamics model including predetermined rotor bending modes of the rotor assembly.

[0008] In yet another embodiment, determining the adjusted electromagnetic force is further based on a proportional compensation factor. In one embodiment, determining the adjusted electromagnetic force is further based on a proportional compensation factor corresponding to a gap between the magnetic actuator and the magnetic material of the rotor assembly. In another embodiment, the proportional compensation factor includes an integral of the output signal corresponding to a current to the rotor assembly corresponding to the adjusted electromagnetic force, and a slope of the current corresponds to the gap between the magnetic actuator and the rotor assembly.

[0009] In various embodiments, the instructions further include filtering an output signal corresponding to the adjusted electromagnetic force based at least on the determined frequency of the rotor bending mode of the determined non-synchronous vibration. In various embodiments, the instructions further include converting the output signal from a digital signal to an analog signal via a current to a power amplifier. In one embodiment, the instructions further include generating the adjusted electromagnetic force corresponding to the output signal to the rotor assembly via a magnetic actuator. In another embodiment, converting the output signal includes converting the output signal from a current unit to a voltage unit corresponding to the adjusted electromagnetic force.

[0010] In yet another embodiment, the instructions further include trending the non-synchronous vibration and the cross-coupled stiffness over a period of time based on a threshold value. In one embodiment, the instructions further include determining a damping factor based at least on the cross-coupled stiffness and the non-synchronous vibration trended over a period of time.

[0011] In one embodiment, the measurement vector includes at least two orthogonal directional vibration signals corresponding to the rotor assembly.

[0012] Another aspect of the present disclosure relates to a turbine, the turbine comprising: a rotor assembly, the rotor assembly comprising a magnetic material; a magnetic actuator, the magnetic actuator positioned to be magnetically connected to the magnetic material of the rotor assembly, wherein the magnetic actuator is configured to selectively output an electromagnetic force at the rotor assembly, and wherein the magnetic actuator is configured to obtain a measurement vector corresponding to the rotor assembly, wherein the measurement vector includes at least two orthogonal direction vibration signals corresponding to the rotor assembly; a controller, the controller configured to store and execute instructions according to one or more instructions described above and further herein.

[0013] These and other features, aspects and advantages of the present invention will be better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A full and enabling disclosure of the invention, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification, which refers to the accompanying drawings, in which:

[0015] Figure 1 is an exemplary schematic cross-sectional view of an embodiment of a turbomachine including a system for detecting, mitigating, and attenuating undesirable rotor dynamics;

[0016] Figure 2 is a schematic diagram of a rotor assembly operably connected to a system for detecting, mitigating and attenuating undesirable rotor dynamics;

[0017] Figure 3 About Figure 1-2 A perspective view of a portion of the system provided;

[0018] Figure 4 is a flow chart outlining the steps of a method for detecting, mitigating and attenuating undesirable rotor dynamics from a rotor assembly; and

[0019] Figure 5 is a schematic diagram of a portion of a system for detecting, mitigating and attenuating undesirable rotor dynamics.

[0020] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention. DETAILED DESCRIPTION

[0021] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are shown in the accompanying drawings. Each example is provided by way of explanation of the present invention rather than limitation thereof. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the scope or spirit of the present invention. For example, a feature shown or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0022] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of the respective components.

[0023] The terms "upstream" and "downstream" refer to relative directions relative to the flow of a fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0024] The approximate values ​​recited herein may include a margin based on one or more measurement devices used in the art, such as, but not limited to, a percentage of the full-scale measurement range of the measurement device or sensor. Alternatively, the approximate values ​​recited herein may include a margin of 10% greater than the upper limit value or less than 10% of the lower limit value of the lower limit value.

[0025] Now referring to the accompanying drawings, Figure 1 1 is an illustrative embodiment of an exemplary engine 10 including an exemplary system for controlling rotor dynamics at the engine 10 (hereinafter referred to as "system 100"). The engine 10 generally includes a rotor assembly 90 including a shaft 92 and a rotor 94. The rotor 94 may define a disk or hub with a plurality of airfoils or blades 98 attached. A further embodiment of the engine 10 includes a casing 18 at least partially surrounding the rotor assembly 90. The casing 18 also includes a bearing assembly, fluid supply and scavenging ducts, dampers, etc. to support and position the rotor assembly 90 relative to the casing 18. In various embodiments, the engine 10 defines a turbomachine configuration, such as, but not limited to, a turbofan engine, a turboprop engine, a turboshaft engine, a turbojet engine, a propfan engine, or other turbomachine configuration. The engine 10 may additionally or alternatively define a thermal engine, such as a Brayton cycle machine.

[0026] Reference now Figure 1-3 , the engine 10 also includes a system 100 that is configured to measure, detect, calculate, or otherwise obtain signals corresponding to vibrations from the operation of the rotor assembly 90 and the forces applied thereto by the system 100. In various embodiments, the system 100 includes a magnetic actuator 110 positioned in magnetic communication with the rotor assembly 90. Various embodiments of the rotor assembly 90 include a magnetic material 96 ( Figure 3 ) at least one region. Various embodiments of the magnetic actuator 110 include a plurality of electromagnetic coils and a magnetic material 96 ( Figure 3 ) laminated stator in electromagnetic communication. The magnetic actuator 110 is configured to selectively output an electromagnetic force (EMF) at the rotor assembly 90 via at least the magnetic material 96 at the rotor assembly 90 based at least on the steps of a method 1000 for controlling rotor dynamics further described herein (hereinafter referred to as “method 1000”).

[0027] In one embodiment, the magnetic material 96 is positioned at the rotor assembly 90 to attenuate unstable forces from the operation of the rotor assembly 90. The magnetic actuator 110 is further positioned proximate to the shaft 92 of the rotor assembly 90 including the magnetic material 96. The unstable forces may generally be referred to as tangential forces at the rotor assembly 90. The unstable forces may specifically refer to aerodynamic excitations due to Alford forces or Alford vortices, or forces generally caused by friction. The magnetic actuator 110 may further be positioned at the rotor assembly 90 to provide active damping to assist or mitigate bow rotor starting (BRS), suppress non-synchronous vibration (NSV), active clearance control, or suppress generally undesirable rotor vibrations. Alford vortex instability may be caused by tangential forces or friction forces (referred to as cross-coupling forces) generated by the deflection of the rotor assembly 90 in the radial direction R. The tangential forces may be caused by uneven or asymmetric clearances between the rotor assembly 90 and the housing 18 surrounding the rotor assembly 90. For example, tangential forces may be caused by uneven blade tip clearance of the rotor 94 of the rotor assembly 90 relative to the inner diameter or shroud of the casing 18 .

[0028] Reference now Figure 2 , further provides an illustrative embodiment of the system 100. The system 100 includes a controller 210 configured to operate the magnetic actuator 110 and determine the output EMF to the rotor assembly 90 to control the rotor dynamics at the rotor assembly 90. Various embodiments of the system 100 include a magnetic actuator 110 configured to detect, measure, calculate, or otherwise obtain a measurement vector corresponding to the rotor assembly 90. In a particular embodiment, the magnetic actuator 110 is configured to obtain the measurement vector via a signal feedback response between the magnetic actuator 110 and the rotor assembly 90. In various embodiments, the magnetic actuator 110 includes or defines an inductance sensor configured to detect, measure, or otherwise determine an inductance change. The measurement vector includes a vibration signal or measurement corresponding to the rotor assembly 90. Still in various embodiments, in addition to the magnetic actuator 110, the system 100 also includes a sensor 102. The sensor 102 may be additionally configured to detect, measure, calculate, or otherwise obtain a measurement vector corresponding to the rotor assembly 90. Various embodiments of sensor 102 may include one accelerometer, or a pair of one or more accelerometers positioned to obtain two orthogonal directional vibration signals corresponding to rotor assembly 90 .

[0029] In certain embodiments, the magnetic actuator 110 provides high speed measurement acquisition and response relative to the lower speed measurement acquisition of the sensor 102 (e.g., the sensor 102 defining an accelerometer, a capacitive probe, etc.). In one embodiment, the sensor 102 can provide a second measurement vector signal that can be compared to a first measurement vector signal from the magnetic actuator 110.

[0030] In various embodiments, the measurement vector corresponds at least in part to the gap 95 between the rotor assembly 90 and the magnetic actuator 110 and / or the sensor 102. In a particular embodiment, the gap 95 is between the magnetic material 96 of the rotor assembly and the magnetic actuator 110. In an embodiment, the sensor 102 can be integrated into the magnetic actuator 110 in order to obtain or quantify the gap 95. In various embodiments, the gap 95 is proportional to the slope of the current through the magnetic actuator 110 and the magnetic material 96 of the rotor assembly 90.

[0031] The magnetic actuator 110, the sensor 102, or both may include a capacitive probe configured to correlate the gap 95 to an output signal corresponding to the current at the magnetic actuator 110. During initial operation of the rotor assembly 90, a baseline EMF corresponding to a baseline current and voltage is provided to the rotor assembly 90 from the magnetic actuator 110.

[0032] During operation of the rotor assembly 90 (i.e., during rotation of the rotor assembly 90), the controller 210 determines non-synchronous vibrations based at least on the measurement vector and the rotational speed or rotor speed of the rotor assembly 90. Synchronous vibrations at the engine 10 may generally be identified at frequencies corresponding to integer multiples of the frequency corresponding to the rotor speed of the rotor assembly 90 (e.g., the 1X frequency). Non-synchronous vibrations at the engine 10 may be identified at frequencies other than integer multiples of the frequency corresponding to the rotor speed. In a particular embodiment, the processor 212 of the controller 210 determines non-synchronous vibrations using the measurement vector defining two orthogonal directional vibration signals and the rotor speed. A Fourier transform or, in particular, a discrete Fourier transform (DFT, Figure 4 ), or other signal conversion algorithms may be further used to provide real-time correlation of the rotor speed to remove the synchronous vibration signal to determine the non-synchronous vibration signal. The processor 212 may utilize a discrete Fourier transform to convert the real-time input rotor speed and the measurement vector signal into samples of a discrete time Fourier transform corresponding to the real-time input. The discrete Fourier transform may specifically determine the amplitude and phase of the non-synchronous vibration corresponding to the rotor assembly 90, or also the rotor speed thereof.

[0033] The associated memory 214 of the controller 210 may further store one or more rotor dynamic models for which the measurement vectors and input signals to the magnetic actuator 110 are tracked in real time to determine the cross-coupling forces or cross-coupling stiffness K at the rotor assembly 90. xyThe rotor dynamics model may include one or more mode shapes corresponding to one or more frequencies of the rotor bending modes at the rotor assembly 90, one or more frequencies corresponding to the rotor speed, and parameterized cross-coupling stiffnesses. The input signal to the magnetic actuator 110 may include an input current or voltage from the power unit 120 at the controller 210. The power unit 120 includes a power amplifier and a power supply for operation of the magnetic actuator 110. During initial operation of the rotor assembly 90, such as during Figure 1-2 The input signal to the magnetic actuator 110, schematically shown at line 122 in , includes a signal corresponding to the baseline EMF. During further operation of the rotor assembly 90, the input signal 122 also includes a signal corresponding to one or more previous signals.

[0034] The cross-coupling stiffness determined at the engine 10 is used to determine an adjusted output EMF from the magnetic actuator 110 to the rotor assembly 90, and an output signal to the magnetic actuator 110 corresponding to the adjusted EMF is generated. Generating the output signal to the magnetic actuator 110 may further include filtering the output signal corresponding to the determined cross-coupling stiffness. The output signal is filtered based on at least one or more determined frequencies corresponding to the rotor bending mode of the non-synchronous vibration and rotor dynamics model. The filtering of the output signal may be performed by a digital-to-analog converter 130 or a DC / AC converter. The DC / AC converter 130 may also convert the output current to an output voltage at the magnetic actuator 110, wherein the output voltage corresponds to the desired gap 95 between the magnetic actuator 110 and the rotor assembly 90.

[0035] Reference now Figure 4 , generally provides a flow chart outlining exemplary steps of a method for controlling rotor dynamics (eg, rotor vortices or Alford vortices) at a rotor assembly of a turbomachine (hereinafter “method 1000”). Figure 4 The method 1000 outlined may utilize Figure 2-3 The method 1000 may be implemented using the system 100 shown and described. Figure 1-2 The system 100 and engine 10 are provided for implementation. However, it should be understood that the method 1000 may be implemented on any engine or system including a magnetic actuator system and controller configured to output electromagnetic forces at a rotor assembly to desirably control rotor dynamics.

[0036] The method 1000 includes outputting a baseline electromagnetic force (EMF) to a rotor assembly via a magnetic actuator at 1010. The baseline EMF may generally correspond to a predetermined output current or voltage signal from a controller (e.g., controller 210) to a magnetic actuator (e.g., magnetic actuator 110) during initial steady-state or transient operation of the rotor assembly.

[0037] During initial operation of the rotor assembly, a sensor (e.g., magnetic actuator 110, sensor 102, or both) detects, measures, calculates, or otherwise obtains a vibration signal from the rotor assembly, such as outlined at step 1020 of method 1000. In various embodiments, an analog-to-digital converter (e.g., Figure 2 The A / D converter 140 in the embodiment of the present invention extracts two orthogonal vibration signals from the original vibration signal obtained from the sensor (e.g., the magnetic actuator 110, the sensor 102, or both). The converted vibration signals may correspond to two orthogonal vibration signals corresponding to the rotor assembly, thereby indicating the amplitude and direction of the vibration at the rotor assembly.

[0038] At 1030, non-synchronous vibration (NSV) corresponding to the rotor assembly is determined based at least on the vibration signal of the rotor assembly and the rotor speed signal. In various embodiments, for example, with respect to Figure 1-3 As described, a discrete Fourier transform is used to determine NSV. The discrete Fourier transform correlates the rotor speed signal (e.g., a frequency signal corresponding to the rotor speed signal) and the vibration signal in real time to remove the synchronous vibration signal from the vibration signal to determine the NSV. The Fourier transform or other signal conversion algorithm converts the raw sensor data into spectral data. The spectral data provides a frequency domain representation from which it can be determined that one or more frequency components of interest in the sensor data (e.g., vibration signals) correspond to a vibration source at the rotor assembly. The spectral data may correspond to two orthogonal direction vibration signals indicating the amplitude and direction of vibration from the rotor assembly.

[0039] The method 1000 further includes determining, at 1040, a cross-coupling stiffness corresponding to the rotor assembly based at least on the vibration signal, the rotor speed signal, and a rotor dynamics model of the rotor assembly, such as with respect to Figure 1-3as described. The rotor dynamics model includes one or more frequencies associated with a rotor bending mode of the rotor assembly. In various embodiments, the method 1000 at 1040 includes, at 1042, obtaining a vibration signal or, in particular, spectral data associated with the NSV signal determined at 1030, and one or more of a current or voltage associated with an output signal to a magnetic actuator, and at 1044, determining a cross-coupling stiffness corresponding to the rotor assembly via the NSV signal and the output signal to the magnetic actuator. In one embodiment, determining the cross-coupling stiffness also includes, at 1046, estimating or trending the rotor dynamics model over a period of time based at least on the vibration signal or, in particular, the determined NSV, and the output signal to the magnetic actuator. Still in various embodiments, trending the rotor dynamics model over a period of time is based at least on the parameterized cross-coupling stiffness, the rotor speed signal, and one or more mode shapes corresponding to one or more frequencies of rotor bending at the rotor assembly.

[0040] At 1050, the method 1000 further includes determining an adjusted output signal to the rotor assembly based at least on the determined cross-coupling stiffness. In various embodiments, the method 1000 further includes generating an adjusted EMF from the magnetic actuator to the rotor assembly based at least on the adjusted output signal at 1060. Still in various embodiments, the adjusted EMF is generated based at least on iteratively determining a control force necessary to operate the rotor assembly at a predetermined threshold vibration signal and rotor speed. In one embodiment, determining the adjusted output signal further includes iteratively determining the control force in real time based on the determined cross-coupling stiffness and also based at least on a damping factor and a compensation factor at 1052.

[0041] In another embodiment, method 1000 further includes, at 1054 , determining a damping factor based at least on the determined cross-coupling stiffness, and at 1046 , the trended rotordynamic model includes the NSV over a period of time.

[0042] In yet another embodiment, the method 1000 further includes, at 1056, providing a magnetic actuator and a rotor assembly (ie, Figure 3 The gap between the magnetic material 96 at the rotor assembly 90 shown (e.g., Figure 2 The gap 95 in the rotor assembly) is used to determine the compensation factor. The gap may generally correspond to the capacitance between the rotor assembly (i.e., the magnetic material of the rotor assembly) and the magnetic actuator. The method 1000 may further include, at 1058, converting an output signal corresponding to a current (e.g., a first output signal) into an output signal corresponding to a voltage (e.g., a second output signal). The first output signal current is integrated with the second output signal voltage, wherein the current signal is proportional to the gap ( Figure 2In various embodiments, the converted output signal at 1058 is converted by a digital-to-analog converter (e.g., Figure 2 The output signal to the magnetic actuator corresponding to the voltage signal generates an adjusted EMF from the magnetic actuator to the rotor assembly, such as outlined at 1060 with respect to method 1000.

[0043] In yet another embodiment, determining the adjusted output signal at 1050 further includes filtering the output signal corresponding to the current signal via the rotor dynamics model based at least on one or more frequencies of the rotor bending mode at 1055. The filtered current signal (e.g., the filtered first output signal) can be converted to a second output signal corresponding to an output voltage to the magnetic actuator, such as described at 1058 and 1060 with respect to method 1000.

[0044] Reference now Figure 4 , further provides a schematic diagram depicting the steps of a system for adaptively stabilizing a rotor assembly (hereinafter referred to as "system 400"). Figure 4 The system 400 is generally described as including Figure 4 Method 1000 and related Figure 1-2 In various embodiments, the system 400 includes an excitation signal generator 410 at which a magnetic actuator 110 ( Figure 1-2 ) is generated to the rotor assembly 90 ( Figure 1 )’s baseline EMF.

[0045] The system 400 may further include an adaptive stability controller 450. The adaptive stability controller 450 iteratively compensates the estimated cross-coupling stiffness based at least on the output signal from the real-time estimator 460. The adaptive stability controller 450 adjusts the magnetic force corresponding to the damping ratio in each orthogonal direction (e.g., from Figure 2 In various embodiments, the ratio of the adjusted magnetic forces in each orthogonal direction accounts for or compensates for asymmetries in the support structure, such as in the surrounding housing 18 ( Figure 1 ) or other framework or support.

[0046] In various embodiments, the real-time estimator 460 provides an online parameterized rotor dynamics model having at least one input cross-coupling stiffness (e.g., output signal from the sub-synchronous filter 420, discussed further below), modal frequency, damping, and mode shape, such as described with respect to method 1000. The real-time estimator 460 may further provide an actuator excitation or stabilization input to a model tracking filter or online estimator. The real-time estimator 460 and steps of method 1000 associated therewith may include determining frequency damping and mode shape with the excitation. The real-time estimator 460 may further include a real-time cross-coupling stiffness K (such as output from the sub-synchronous filter 420) xy In various embodiments, the real-time estimator 460 may provide real-time signal detection, for example, at steady-state rotor speed, transient rotor speed, or both.

[0047] The system 400 also includes a sub-synchronous filter or sub-synchronous filter 420 that at least partially defines the first feedback controller 411. The first feedback controller 411 may include a differential controller to adjust the damping of the engine 10 and the system 100. The system 400 includes a proportional controller 422 that is configured to stabilize the magnetic actuator 110 ( Figure 1-2 ) generated by the negative stiffness. In various embodiments, the sub-synchronous filter 420 also includes a differential controller configured to adjust the damping via a damping factor (such as determined at 1056 via method 1000). The sub-synchronous filter 420 may also include a cross-coupling stiffness compensator 426 configured to determine a cross-coupling stiffness K based on at least the estimated cross-coupling stiffness (such as determined at 1044 via method 1000). xy In various embodiments, the sub-synchronous filter 420 provides substantially no phase loss filtering for non-wide bandwidths compared to passive damper control systems for magnetic actuators or bearings.

[0048] The proportional controller 422 can be based on at least the sub-synchronous filter 420 and the cross-coupling stiffness K xy In various embodiments, the slope of the current from the system 400 is related to the rotor assembly 90 and the magnetic actuator 110 ( Figure 2 ) are proportional to the gap 95 between them.

[0049] The system 400 may include a second feedback controller 412 that provides a first signal to the cross-coupled stiffness compensator 426 and a second signal to the real-time estimator 460. The second feedback controller 412 may include a self-sensing controller 430 configured with narrow bandwidth signal processing. The self-sensing controller 430 may be configured to receive an output signal from the proportional controller 422. The self-sensing controller 430 is configured to determine the magnetic actuator 110 and the rotor assembly 90 ( Figure 1-2 ) (for example, Figure 2 The self-sensing controller 430 may also determine the gap 95 via the magnetic actuator 110 without directly measuring via an external sensor (e.g., the magnetic actuator 110, the sensor 102, or both). The self-sensing controller 430 may be configured to perform steps corresponding to the method 1000. In various embodiments, the self-sensing controller 430 defines the sensor 150 ( Figure 2 ), the sensor 150 provides sensing of the rotor assembly 90 and the magnetic actuator 110 ( Figure 2 ) between 95( Figure 2 )'s magnetic self-sensing sensor.

[0050] The system 400 may further include a synchronous filter 440 configured to receive a signal output from the sensing controller 430 and a signal from the rotor assembly 90 ( Figure 1-2 ) speed signal. The synchronous filter 440 may include a Fourier transform or a discrete Fourier transform (DFT) to provide real-time correlation of the rotor speed to remove the synchronous vibration signal to determine the non-synchronous vibration signal, such as described with respect to method 1000. The output signal from the self-sensing controller 430 may be provided online correlation using the synchronous filter 440 to subtract or remove the synchronous vibration signal from the output signal. Such online correlation may particularly minimize phase distortion of the output signal.

[0051] Referring back to the first controller 411, the system 400 may further include a performance health monitoring (PHM) unit 470. In one embodiment, the PHM unit 470 includes an excitation signal generator configured to generate an excitation signal (e.g., a damping signal) and apply the excitation signal (e.g., a damping signal) to the magnetic actuator 110. The excitation signal may define a multi-sine signal, a swept frequency signal, or a random signal. The excitation signal may be based at least in part on the estimated cross-coupling stiffness to determine and generate a rotor effective damping or an effective damping ratio at the rotor assembly 90, such as described with respect to the method 1000.

[0052] Relative to Figure 1-4The illustrated and described embodiments of the engine 10, system 100, and method 1000 may provide improved apparatus and methods for controlling engine rotor dynamics, such as generally damping unwanted vibrations, or providing active clearance control, or suppressing BRS, or specifically damping or mitigating Alford vortices or NSVs, or rotor vortices caused by rotor friction (e.g., due to friction forces). The embodiments provided herein may further provide active damping and feedback control to mitigate unwanted vibrations. The embodiments provided herein may specifically target tangential forces, or utilize signals or measurements corresponding to tangential forces instead of, or in addition to, speed driving forces.

[0053] In general, controller 210 may correspond to any suitable processor-based device, including one or more computing devices. For example, Figure 1 One embodiment of suitable components that may be included in controller 210 is shown. Figure 1 As shown, the controller 210 may include a processor 212 and an associated memory 214 configured to perform various computer-implemented functions (e.g., perform the methods, steps, calculations, etc. disclosed herein). As used herein, the term "processor" refers not only to integrated circuits included in what is known in the art as a computer, but also to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and other programmable circuits. In addition, the memory 214 may generally include memory elements, including but not limited to computer-readable media (e.g., random access memory (RAM)), computer-readable non-volatile media (e.g., flash memory), compact disk-read-only memory (CD-ROM), magneto-optical disk (MOD), digital versatile disk (DVD), and / or other suitable memory elements, or a combination thereof. In various embodiments, the controller 210 may define one or more of a full authority digital engine controller (FADEC), a propeller control unit (PCU), an engine control unit (ECU), or an electronic engine control (EEC).

[0054] As shown, the controller 210 may include control logic 216 stored in the memory 214. The control logic 216 may include instructions that, when executed by the one or more processors 212, cause the one or more processors 212 to perform operations, such as Figure 2-4 The steps of method 1000 are summarized and described.

[0055] In addition, if Figure 1As shown, the controller 210 may also include a communication interface module 230. In several embodiments, the communication interface module 230 may include associated electronic circuits for sending and receiving data. In this way, the communication interface module 230 of the controller 210 may be used to receive data from the rotor assembly 90 or one or more other parts of the system 100, 400. In addition, the communication interface module 230 may also be used to communicate with any other suitable component of the engine 10 (including any number of sensors configured to detect, determine, mitigate or otherwise stabilize undesirable rotor dynamics, vibrations, rotor vortices, clearances, or other operating modes of the rotor assembly 90 and the engine 10). It should be understood that the communication interface module 230 may be any combination of appropriate wired and / or wireless communication interfaces, and may therefore be communicatively coupled to one or more components of the engine 10 via a wired and / or wireless connection. In this way, the controller 210 can obtain, determine, store, generate, transmit, or operate any one or more steps of method 1000 at the engine 10, a device to which the engine 10 is attached (e.g., an aircraft), or a ground-based, airborne, or satellite-based device (e.g., a distributed network) that communicates with the engine 10.

[0056] The various embodiments of the engine 10 and the systems 100, 400 shown and described herein can provide desired improvements for damping systems for rotor assemblies and turbines. In various embodiments, the systems 100, 400 can provide direct targeting of unstable tangential forces generated by cross-coupled stiffness, rather than general vibration damping. Compared with a separate passive damping system or a proportional / differential controller, the provided systems 100, 400 can provide damping and feedback control between one or more controllers and a magnetic actuator and a rotor assembly. Additionally or alternatively, the systems 100, 400 shown and described herein can be targeted at a frequency bandwidth of a narrower sub-synchronous region rather than a wide bandwidth control such as may occur with respect to a passive damping system. Further or alternatively, the embodiments provided herein can provide desired feedback control, a narrower target bandwidth frequency, or other benefits relative to eddy current detection (e.g., Alford eddy current), cross-coupled force identification, stability margin testing and identification, ad generation of stable forces, damping, clearance control, NSV suppression, bow rotor startup assistance or relief, or other mitigation of undesirable rotor dynamics.

[0057] In exemplary embodiments of the systems 100, 400, engine 10, and operation thereof, when unstable operation of the rotor assembly occurs (e.g., rotor vortices, Alford forces, etc.), the systems 100, 400, or methods 1000 applied to the engine 10 can provide damping and feedback control to the rotor assembly 90 via the magnetic actuator 110 within a fraction of a second. Because unstable operation of the rotor assembly may result in relatively rapid and exponential growth of vibrations (e.g., within 1 to 2 seconds), imbalance, eccentric movement, rotor vortices, undesirable tangential forces, or other operating modes that may damage the rotor assembly, surrounding housing, supports, or other portions of the engine, or complete engine failure, the embodiments of the systems 100, 400, engine 10, and methods 1000 provided herein can provide damping and feedback control to mitigate or eliminate the propagation of one or more such undesirable rotor dynamics of the rotor assembly.

[0058] In an exemplary embodiment, the system 100, 400, engine 10 and / or method 1000 can provide the desired damping and feedback within 1 second. For example, the system 100, 400 or method 1000 can determine and generate one or more signals, responses, outputs or other actions described herein within 1 second. In another exemplary embodiment, the system 100, 400, engine 10 and / or method 1000 can provide the desired damping and feedback within 750 milliseconds. In yet another exemplary embodiment, the system 100, 400, engine 10 and / or method 1000 can provide the desired damping and feedback within 500 milliseconds. In yet another exemplary embodiment, the system 100, 400, engine 10 and / or method 1000 can provide the desired damping and feedback within 250 milliseconds. In yet another exemplary embodiment, the system 100, 400, engine 10 and / or method 1000 can provide the desired damping and feedback within 100-250 milliseconds. It should be understood that embodiments of the systems, methods, and engines provided herein may provide improvements over other methods, systems, engines, sensors, or computing devices, or combinations thereof (e.g., those for detecting, determining, or generating signals, responses, or operations for damping, mitigating, or eliminating vibrations, tangential forces, eddy currents, or other undesirable rotor dynamics at a rotor assembly).

[0059] This written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any device or system and performing any combined 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. If such other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims, these other examples are intended to fall within the scope of the claims.

[0060] Further aspects of the invention are provided by the subject matter of the following clauses:

[0061] 1. A system for controlling rotor dynamics at a rotor assembly, the system comprising: a magnetic actuator positioned in magnetic communication with the rotor assembly, wherein the magnetic actuator is configured to selectively output an electromagnetic force at the rotor assembly, and wherein the magnetic actuator is configured to obtain a measurement vector indicative of a rotor dynamic parameter; a controller configured to store and execute instructions, the instructions comprising: outputting a baseline electromagnetic force to the rotor assembly; obtaining the measurement vector at the rotor assembly; determining a non-synchronous vibration corresponding to the rotor assembly based on at least the measurement vector and a rotor speed of the rotor assembly; determining a cross-coupling stiffness corresponding to the rotor assembly based on at least the measurement vector, the rotor speed, and a predetermined rotor dynamic model of the rotor assembly; determining an adjusted electromagnetic force of the rotor assembly based on at least the cross-coupling stiffness and a damping factor corresponding to the electromagnetic force output from the magnetic actuator; and generating an output signal corresponding to the adjusted electromagnetic force to the rotor assembly.

[0062] 2. A system according to any preceding clause, wherein determining the non-synchronous vibrations comprises removing the synchronous vibration signals via a Fourier transform function.

[0063] 3. The system of any preceding clause, wherein determining the cross-coupling stiffness is further based on at least a predetermined rotor dynamics model including predetermined rotor bending modes of the rotor assembly.

[0064] 4. A system according to any preceding clause, wherein determining the adjusted electromagnetic force is further based on a proportional compensation factor.

[0065] 5. The system of any preceding clause, the instructions further comprising filtering an output signal corresponding to the adjusted electromagnetic force based at least on the determined frequency of the determined rotor bending mode of non-synchronous vibration.

[0066] 6. The system of any preceding clause, the instructions further comprising converting the output signal from a digital signal to an analog signal via a current to a power amplifier.

[0067] 7. The system of any preceding clause, the instructions further comprising generating, via the magnetic actuator, a modulated electromagnetic force corresponding to the output signal to the rotor assembly.

[0068] 8. The system of any preceding clause, wherein converting the output signal comprises converting the output signal from a current unit to a voltage unit corresponding to the adjusted electromagnetic force.

[0069] 9. The system of any preceding clause, the instructions further comprising trending the asynchronous vibration and cross-coupled stiffness based on a threshold over a period of time.

[0070] 10. The system of any preceding clause, the instructions further comprising determining a damping factor based at least on a cross-coupled stiffness and non-synchronous vibration trended over a period of time.

[0071] 11. A system according to any preceding clause, wherein the measurement vector comprises at least two orthogonal directional vibration signals corresponding to the rotor assembly.

[0072] 12. A turbine, the turbine comprising: a rotor assembly, the rotor assembly comprising a magnetic material; a magnetic actuator, the magnetic actuator positioned in magnetic communication with the magnetic material of the rotor assembly, wherein the magnetic actuator is configured to selectively output an electromagnetic force at the rotor assembly, and further wherein the magnetic actuator is configured to obtain a measurement vector corresponding to the rotor assembly; a controller, the controller configured to store and execute instructions. The instructions include: outputting a baseline electromagnetic force to the rotor assembly via the magnetic actuator; obtaining a measurement vector at the rotor assembly via the magnetic actuator; determining an asynchronous vibration corresponding to the rotor assembly based on at least the measurement vector and a rotor speed of the rotor assembly; determining a cross-coupling stiffness corresponding to the rotor assembly based on at least the measurement vector, the rotor speed, and a predetermined rotordynamic model of the rotor assembly; determining an adjusted electromagnetic force of the rotor assembly based on at least the cross-coupling stiffness and a damping factor corresponding to the electromagnetic force output from the magnetic actuator; generating an output signal corresponding to the adjusted electromagnetic force to the rotor assembly.

[0073] 13. A turbine according to any preceding clause, wherein determining non-synchronous vibrations comprises removing synchronous vibration signals via a Fourier transform function.

[0074] 14. A turbine according to any preceding clause, wherein determining the cross-coupling stiffness is further based on at least a predetermined rotor dynamics model including predetermined frequencies of rotor bending modes.

[0075] 15. A turbine according to any preceding clause, the instructions further comprising filtering an output signal corresponding to the adjusted electromagnetic force based at least on the determined frequency of the determined rotor bending mode of non-synchronous vibration.

[0076] 16. A turbine according to any of the preceding clauses, the instructions further comprising: converting the output signal from a current corresponding to the digital signal to a voltage corresponding to the analog signal, wherein the analog signal corresponds to the adjusted electromagnetic force; generating the adjusted electromagnetic force corresponding to the output signal to the magnetic material at the rotor assembly via the magnetic actuator.

[0077] 17. A turbine according to any preceding clause, the instructions further comprising: trending the non-synchronous vibration and the cross-coupling stiffness over a period of time based on a threshold value; determining the damping factor based on at least the cross-coupling stiffness and the non-synchronous vibration trended over a period of time.

[0078] 18. A turbine according to any preceding clause, wherein determining the adjusted electromagnetic force is further based on a proportional compensation factor corresponding to a gap between the magnetic actuator and the magnetic material of the rotor assembly.

[0079] 19. A turbine according to any preceding clause, wherein the proportional compensation factor comprises an integral of the output signal corresponding to a current to the rotor assembly corresponding to the adjusted electromagnetic force, and wherein the slope of the current corresponds to the gap between the magnetic actuator and the rotor assembly.

[0080] 20. A turbine according to any preceding clause, comprising a system according to any preceding clause.

[0081] 21. A method for controlling a rotor assembly of a turbine, the method comprising: outputting a baseline electromagnetic force to the rotor assembly via a magnetic actuator; obtaining a measurement vector corresponding to a vibration signal from the rotor assembly; obtaining a rotor speed signal of the rotor assembly, wherein the rotor speed signal corresponds to a frequency speed of the rotor assembly; determining an asynchronous vibration corresponding to the rotor assembly based at least on the measurement vector and the rotor speed signal of the rotor assembly; determining a cross-coupling stiffness corresponding to the rotor assembly based at least on the measurement vector, the rotor speed signal and a predetermined rotor dynamics model of the rotor assembly, wherein the predetermined rotor dynamics model includes a predetermined frequency of a rotor bending mode; determining an adjusted electromagnetic force of the rotor assembly based at least on the cross-coupling stiffness and a damping factor corresponding to the electromagnetic force output from the magnetic actuator; and generating an output signal corresponding to the adjusted electromagnetic force to the rotor assembly.

[0082] 22. A method according to any preceding clause, wherein determining non-synchronous vibrations comprises removing synchronous vibration signals via a Fourier transform function.

[0083] 23. A method according to any preceding clause, wherein determining the cross-coupling stiffness is further based on at least a predetermined rotor dynamics model including predetermined rotor bending modes of the rotor assembly.

[0084] 24. A method according to any preceding clause, wherein determining the adjusted electromagnetic force is further based on a proportional compensation factor.

[0085] 25. A method according to any preceding clause, further comprising filtering an output signal corresponding to the adjusted electromagnetic force based at least on the determined frequency of the determined rotor bending mode of non-synchronous vibration.

[0086] 26. A method according to any preceding clause, further comprising converting the output signal from a digital signal to an analog signal via a current to a power amplifier.

[0087] 27. A method according to any preceding clause, further comprising generating a modulated electromagnetic force corresponding to the output signal to the rotor assembly via a magnetic actuator.

[0088] 28. The method of any preceding clause, wherein converting the output signal comprises converting the output signal from a current unit to a voltage unit corresponding to the adjusted electromagnetic force.

[0089] 29. The method of any preceding clause, further comprising trending the asynchronous vibration and cross-coupled stiffness based on a threshold over a period of time.

[0090] 30. A method according to any preceding clause, further comprising determining a damping factor based at least on the cross-coupled stiffness and the non-synchronous vibration trended over a period of time.

[0091] 31. A method according to any preceding clause, wherein the measurement vector comprises at least two orthogonal directional vibration signals corresponding to the rotor assembly.

[0092] 32. A method according to any preceding clause, wherein one or more steps of the method are stored in a system of any preceding clause, and wherein a controller of any preceding clause is configured to perform one or more steps of the method.

[0093] 33. A method as claimed in any preceding clause, for use in controlling a turbine as claimed in any preceding clause.

Claims

1. A system for controlling rotor dynamics at a rotor assembly, characterized in that The system comprises: a magnetic actuator positioned in magnetic communication with the rotor assembly, wherein the magnetic actuator is configured to selectively output an electromagnetic force at the rotor assembly, and wherein the magnetic actuator is configured to obtain a measurement vector indicative of a rotordynamic parameter; and A controller configured to store and execute instructions, the instructions comprising: outputting electromagnetic force to the rotor assembly; obtaining the measurement vector at the rotor assembly; determining a non-synchronous vibration corresponding to the rotor assembly based at least on the measurement vector and a rotor speed of the rotor assembly; determining a cross-coupling stiffness corresponding to the rotor assembly based at least on the measurement vector, the rotor speed, and a predetermined rotordynamic model of the rotor assembly; determining an adjusted electromagnetic force of the rotor assembly based at least on the cross-coupling stiffness and a damping factor corresponding to the electromagnetic force output from the magnetic actuator; and generating an output signal corresponding to the adjusted electromagnetic force of the rotor assembly, Wherein determining the adjusted electromagnetic force is further based on a proportional compensation factor corresponding to a gap between the magnetic actuator and a magnetic material of the rotor assembly.

2. The system according to claim 1, characterized in that in, Determining the non-synchronous vibration includes removing the synchronous vibration signal via a Fourier transform function.

3. The system according to claim 1, characterized in that in, Determining the cross-coupling stiffness is further based at least on the predetermined rotordynamic model including predetermined rotor bending modes of the rotor assembly.

4. The system according to claim 1, characterized in that in, The proportional compensation factor includes an integral of the output signal corresponding to a current to the rotor assembly corresponding to the adjusted electromagnetic force, and wherein a slope of the current corresponds to the gap between the magnetic actuator and the rotor assembly.

5. The system according to claim 1, characterized in that The instructions further include: The output signal corresponding to the adjusted electromagnetic force is filtered based on at least the determined frequency of the determined rotor bending mode of non-synchronous vibration.

6. The system according to claim 5, characterized in that The instructions further include: The output signal is converted from a digital signal to an analog signal via a digital-to-analog converter.

7. The system according to claim 6, characterized in that The instructions further include: The modulated electromagnetic force corresponding to the output signal is generated for the rotor assembly via the magnetic actuator.

8. The system according to claim 6, characterized in that in, Converting the output signal includes converting the output signal from an output current to an output voltage corresponding to the adjusted electromagnetic force.

9. The system according to claim 1, characterized in that The instructions further include: The asynchronous vibration and the cross-coupled stiffness are trended based on a threshold over a period of time.

10. The system according to claim 9, characterized in that The instructions further include: The damping factor is determined based on at least the cross-coupling stiffness and the trended non-synchronous vibration over the period of time.

11. The system according to claim 1, characterized in that in, The measurement vector includes at least two orthogonal directional vibration signals corresponding to the rotor assembly.

12. A turbine, characterized in that: The turbine comprises: a rotor assembly, the rotor assembly comprising a magnetic material; a magnetic actuator positioned in magnetic communication with the magnetic material of the rotor assembly, wherein the magnetic actuator is configured to selectively output an electromagnetic force at the rotor assembly, and further wherein the magnetic actuator is configured to obtain a measurement vector corresponding to the rotor assembly; and A controller configured to store and execute instructions, the instructions comprising: outputting electromagnetic force to the rotor assembly via the magnetic actuator; obtaining the measurement vector at the rotor assembly via the magnetic actuator; determining a non-synchronous vibration corresponding to the rotor assembly based at least on the measurement vector and a rotor speed of the rotor assembly; determining a cross-coupling stiffness corresponding to the rotor assembly based at least on the measurement vector, the rotor speed, and a predetermined rotordynamic model of the rotor assembly; determining an adjusted electromagnetic force of the rotor assembly based at least on the cross-coupling stiffness and a damping factor corresponding to the electromagnetic force output from the magnetic actuator; and generating an output signal corresponding to the adjusted electromagnetic force of the rotor assembly, Wherein determining the adjusted electromagnetic force is further based on a proportional compensation factor corresponding to a gap between the magnetic actuator and the magnetic material of the rotor assembly.

13. The turbine according to claim 12, characterized in that in, Determining the non-synchronous vibration includes removing the synchronous vibration signal via a Fourier transform function.

14. The turbine according to claim 12, characterized in that in, Determining the cross-coupling stiffness is further based at least on the predetermined rotor dynamics model including predetermined frequencies of rotor bending modes.

15. The turbine according to claim 12, characterized in that The instructions further include: The output signal corresponding to the adjusted electromagnetic force is filtered based on at least the determined frequency of the determined rotor bending mode of non-synchronous vibration.

16. The turbine according to claim 15, characterized in that The instructions further include: converting the output signal from a current corresponding to a digital signal to a voltage corresponding to an analog signal, wherein the analog signal corresponds to the adjusted electromagnetic force; and The modulated electromagnetic force corresponding to the output signal is generated to the magnetic material at the rotor assembly via the magnetic actuator.

17. The turbine according to claim 12, characterized in that The instructions further include: trending the asynchronous vibration and the cross-coupled stiffness based on a threshold over a period of time; and The damping factor is determined based on at least the cross-coupling stiffness and the trended non-synchronous vibration over the period of time.

18. The turbine according to claim 12, characterized in that in, The proportional compensation factor includes an integral of the output signal corresponding to a current to the rotor assembly corresponding to the adjusted electromagnetic force, and wherein a slope of the current corresponds to the gap between the magnetic actuator and the rotor assembly.

19. A method for controlling a rotor assembly of a turbomachine, characterized in that: The method comprises: outputting electromagnetic force to the rotor assembly via a magnetic actuator; obtaining a measurement vector corresponding to a vibration signal from the rotor assembly; obtaining a rotor speed signal of the rotor assembly, wherein the rotor speed signal corresponds to a frequency speed of the rotor assembly; determining a non-synchronous vibration corresponding to the rotor assembly based at least on the measurement vector and the rotor speed signal of the rotor assembly; determining a cross-coupling stiffness corresponding to the rotor assembly based at least on the measurement vector, the rotor speed signal, and a predetermined rotordynamic model of the rotor assembly, wherein the predetermined rotordynamic model includes predetermined frequencies of rotor bending modes; determining an adjusted electromagnetic force of the rotor assembly based at least on the cross-coupling stiffness and a damping factor corresponding to the electromagnetic force output from the magnetic actuator; and generating an output signal corresponding to the adjusted electromagnetic force of the rotor assembly, wherein determining the adjusted electromagnetic force is further based on a proportional compensation factor corresponding to a gap between the magnetic actuator and a magnetic material of the rotor assembly, wherein the proportional compensation factor comprises an integral of the output signal corresponding to a current to the rotor assembly corresponding to the adjusted electromagnetic force, and wherein a slope of the current corresponds to the gap between the magnetic actuator and the rotor assembly.

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