System and method for operating generator of grid-forming inverter-based resource

Abstract

A method for operating a generator of a grid-forming inverter-based resource. The generator has a rotor and a stator. The method includes receiving, via a controller, an actual generator signal associated with a reference signal or a command signal of the generator. The method also includes determining, via the controller, an expected generator signal associated with the actual generator signal based, at least in part, on a plurality of electrical feedback signals. Further, the method includes determining, via the controller, an error signal based on a difference between the expected generator signal and the actual generator signal. The error signal is representative of a rotor position error with respect to a synchronous reference frame. Moreover, the method includes correcting, via the controller, a rotor signal associated with a command signal or a feedback signal of the rotor based on the error signal. In addition, the method includes controlling, via the controller, the generator based on the corrected rotor signal.

Description

701060-WO-1 / GECW-1285-PCTSYSTEM AND METHOD FOR OPERATING GENERATOR OF GRID-FORMING INVERTER-BASED RESOURCEFIELD

[0001] The present disclosure relates generally to inverter-based resources, such as wind turbines, and more particularly, to systems and methods for operating a generator of a grid-forming inverter-based resource.BACKGROUND

[0002] Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modem wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. For example, rotor blades typically have the cross-sectional profde of an airfoil such that, during operation, air flows over the blade producing a pressure difference between the sides. Consequently, a lift force, which is directed from a pressure side towards a suction side, acts on the blade. The lift force generates torque on the main rotor shaft, which is typically geared to a generator for producing electricity.

[0003] Wind turbines can be distinguished in two types: fixed speed and variable speed turbines. Conventionally, variable speed wind turbines are controlled as current sources connected to a power grid. In other words, the variable speed wind turbines rely on a grid frequency detected by a phase locked loop (PLL) as a reference and inject a specified amount of current into the grid. The conventional current source control of the wind turbines is based on the assumptions that the grid voltage waveforms are fundamental voltage waveforms with fixed frequency and magnitude and that the penetration of wind power into the grid is low enough so as to not cause disturbances to the grid voltage magnitude and frequency. Thus, the wind turbines simply inject the specified current into the grid based on the fundamental voltage waveforms. However, with the rapid growth of the wind power, wind power penetration into some grids has increased to the point where wind turbine generators have a significant impact on the grid voltage and frequency. When wind turbines are located in a weak grid, wind turbine power fluctuations may lead to an increase in701060-WO-1 / GECW-1285-PCT variations in the grid voltage.

[0004] Furthermore, many existing renewable generation converters, such as wind turbine generators, operate in a “grid-following’7mode. Grid-following type devices utilize fast current-regulation loops to control active and reactive power exchanged with the grid. More specifically, FIG. 1 illustrates the basic elements of the main circuit and converter control structure for a grid-following wind turbine generator. As shown, the active power reference to the converter is developed by the energy source regulator, e.g., the turbine control portion of a wind turbine. This is conveyed as a torque reference which represents the lesser of the maximum attainable power from the energy source at that instant, or a curtailment command from a higher-level grid controller. The converter control then determines a current reference for the active component of current to achieve the desired torque. Accordingly, the wind turbine generator includes functions that manage the voltage and reactive power in a manner that results in a command for the reactive component of current. Wide-bandwidth current regulators then develop commands for voltage to be applied by the converters to the system, such that the actual currents closely track the commands.

[0005] Alternatively, grid-forming type converters provide a voltage-source characteristic, where the angle and magnitude of the voltage are controlled to achieve the regulation functions needed by the grid. With this structure, current will flow according to the demands of the grid while the converter contributes to establishing a voltage and frequency for the grid. This characteristic is comparable to conventional generators based on a turbine driving a synchronous machine. Thus, a grid-forming source must include the following basic functions: (1) support grid voltage and frequency for any current flow within the rating of the equipment, both real and reactive; (2) prevent operation beyond equipment voltage or current capability by allowing grid voltage or frequency to change rather than disconnecting equipment (disconnection is allowed only when voltage or frequency are outside of bounds established by the grid entity); (3) remain stable for any grid configuration or load characteristic, including serving an isolated load or connected with other grid-forming sources, and switching between such configurations; (4) share total load of the grid among other grid-forming sources connected to the grid; (5) ride through grid disturbances, both major and minor, and (6) meet requirements (l)-(5) without701060-WO-1 / GECW-1285-PCT requiring fast communication with other control systems existing in the grid, or externally-created logic signals related to grid configuration changes.

[0006] The basic control structure to achieve the above grid-forming objectives was developed and field-proven for battery systems in the early 1990’s (see e.g., United States Patent No.: 5,798,633 entitled “Battery Energy Storage Power Conditioning System”). Applications to full-converter wind generators and solar generators are disclosed in United States Publication No.: 2010 / 0142237 entitled “System and Method for Control of a Grid Connected Power Generating System,” and United States Patent No.: 9,270,194 entitled “Controller for controlling a power converter.” However, such implementations have been employed on full-converter wind generators.

[0007] Oftentimes, various sensors may provide electrical feedbacks to gnd- forming type converters for use in controlling voltages that achieves the regulation functions needed by the grid. However, the sensor(s) may be susceptible to inaccuracies (e g., due to processing time delays and / or physical displacements of the sensor(s) along a shaft with respect to generator windings). As such, these inaccuracies may manifest as errors (e g., with respect to a synchronous reference frame) in feedback signals that are used to control the voltage, which may lead to instability and / or non-linear control responses, excessive steady-state error, and / or undesirable compensation by higher-level controllers.

[0008] In view of the foregoing, the present disclosure is directed to a system and method operating a generator of a grid-forming (GFM) inverter-based resource (IBR).BRIEF DESCRIPTION

[0009] 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.

[0010] In an aspect, the present disclosure is directed to a method for operating a generator of a grid-forming inverter-based resource. The generator has a rotor and a stator. The method includes receiving, via a controller, an actual generator signal associated with a reference signal or a command signal of the generator. The method also includes determining, via the controller, an expected generator signal associated701060-WO-1 / GECW-1285-PCT with the actual generator signal based, at least in part, on a plurality of electrical feedback signals. Further, the method includes determining, via the controller, an error signal based on a difference between the expected generator signal and the actual generator signal. The error signal is representative of a rotor position error with respect to a synchronous reference frame. Moreover, the method includes correcting, via the controller, a rotor signal associated with a command signal or a feedback signal of the rotor based on the error signal. In addition, the method includes controlling, via the controller, the generator based on the corrected rotor signal.

[0011] In another aspect, the present disclosure is directed to a wind turbine including a generator having a rotor and a stator, and a controller comprising at least one processor. The at least one processor is configured to perform a plurality of operations. The plurality of operations includes receiving an actual generator signal associated with a reference signal or a command signal of the generator. The plurality of operations also includes determining an expected generator signal associated with the actual generator signal based, at least in part, on a plurality of electrical feedback signals. Further, the plurality of operations includes determining an error signal based on a difference between the expected generator signal and the actual generator signal. The error signal is representative of a rotor position error with respect to a synchronous reference frame. Moreover, the plurality of operations includes correcting a rotor signal associated with a command signal or a feedback signal of the rotor based on the error signal. In addition, the plurality of operations includes controlling the generator based on the corrected rotor signal.

[0012] These and other features, aspects and advantages of the present invention will become 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 invention and, together with the description, serve to explain the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:701060-WO-1 / GECW-1285-PCT

[0014] FIG. 1 illustrates a one-line diagram of a wind turbine generator with structure of converter controls for grid-following application according to conventional construction;

[0015] FIG. 2 illustrates a perspective view of an embodiment of a wind turbine according to the present disclosure;

[0016] FIG. 3 illustrates a simplified, internal view of an embodiment of a nacelle according to the present disclosure;

[0017] FIG. 4 illustrates a schematic view of an embodiment of a wind turbine electrical power system suitable for use with the wind turbine shown in FIG. 1;

[0018] FIG. 5 illustrates a schematic view of an embodiment of a wind farm having a plurality’ of wind turbines according to the present disclosure;

[0019] FIG. 6 illustrates a block diagram of an embodiment of a controller according to the present disclosure;

[0020] FIG. 7 illustrates a one-line diagram of an embodiment of a wind turbine generator with converter controls for grid-forming application according to the present disclosure;

[0021] FIG. 8 illustrates a one-line diagram of another embodiment of a wind turbine generator with converter controls for grid-forming application according to the present disclosure;

[0022] FIG. 9 illustrates a flow diagram of an embodiment of a method for operating a grid-forming (GFM) inverter-based resource (IBR) having a generator according to the present disclosure;

[0023] FIG. 10 illustrates a schematic diagram of an embodiment of an error correction calculation module for controlling the generator according to the present disclosure; and

[0024] FIG. 11 illustrates a schematic diagram of another embodiment of an error correction calculation module for controlling the generator according to the present disclosure.DETAILED DESCRIPTION

[0025] Reference now will be made in detail to embodiments of the invention, one or more examples of w hich are illustrated in the drawings. Each example is701060-WO-1 / GECW-1285-PCT provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of an embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0026] A grid-forming (GFM) inverter-based resource (IBR), such as a wind turbine, receives electrical feedbacks, such as voltage feedbacks, frequency feedbacks (e.g., from the phase-locked loop (PLL)), current feedbacks, position feedbacks, etc. GFM wind turbines typically have control functions for providing GFM control for generators that generate command signals based on the electrical feedbacks. Various sensors may be arranged within the GFM wind turbine for sensing and providing the electrical feedbacks. However, the various sensors may be susceptible to inaccuracies (e g., due to processing time delays and / or physical displacements of the sensor(s) along a shaft with respect to generator windings). As such, these inaccuracies may manifest as errors (e g., with respect to a synchronous reference frame) in feedback signals that are used to generate command signals, which may lead to instability and / or non-linear control responses, excessive steady-state error, and / or undesirable compensation by higher-level controllers.

[0027] In view of the foregoing, the present disclosure is directed to systems and methods for operating a generator of a GFM IBR, such as a wind turbine. In particular, systems and methods of the present disclosure include determining an error signal based on a difference between an expected generator signal derived from a plurality of electrical feedback signals and an actual generator signal associated with a reference signal or a command signal of the generator. The generator is then controlled based on a corrected rotor signal that accounts for the error signal, which can increase a likelihood of the generator being controlled to achieve regulation functions needed by a power grid.

[0028] Referring now to the drawings, FIG. 2 illustrates a perspective view of an embodiment of a wind turbine 10 according to the present disclosure. As shown, the wind turbine 10 generally includes a tower 12 extending from a support surface 14, a701060-WO-1 / GECW-1285-PCT nacelle 16 mounted on the tower 12, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to and extending outwardly from the hub 20. For example, in the illustrated embodiment, the rotor 18 includes three rotor blades 22. However, in an alternative embodiment, the rotor 18 may include more or less than three rotor blades 22. Each rotor blade 22 may be spaced about the hub 20 to facilitate rotating the rotor 18 to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy. For instance, the hub 20 may be rotatably coupled to an electric generator 24 (FIG. 3) positioned within the nacelle 16 to permit electrical energy to be produced.

[0029] The wind turbine 10 may also include a wind turbine controller 26 centralized within the nacelle 16. However, in other embodiments, the controller 26 may be located within any other component of the wind turbine 10 or at a location outside the wind turbine 10. Further, the controller 26 may be communicatively coupled to any number of the components of the wind turbine 10 in order to control the operation of such components and / or implement a corrective or control action. As such, the controller 26 may include a computer or other suitable processing unit. Thus, in several embodiments, the controller 26 may include suitable computer- readable instructions that, when implemented, configure the controller 26 to perform various different functions, such as receiving, transmitting and / or executing wind turbine control signals. Accordingly, the controller 26 may generally be configured to control the various operating modes (e.g., start-up or shut-down sequences), de-rating or up-rating the wind turbine, and / or individual components of the wind turbine 10.

[0030] Referring now to FIG. 3, a simplified, internal view of an embodiment of the nacelle 16 of the wind turbine 10 show n in FIG. 2 is illustrated. As shown, a generator 24 may be disposed within the nacelle 16 and supported atop a bedplate 46. In general, the generator 24 may be coupled to the rotor 18 for producing electrical power from the rotational energy generated by the rotor 18. For example, as shown in the illustrated embodiment, the rotor 18 may include a rotor shaft 34 coupled to the hub 20 for rotation therewith. The rotor shaft 34 may, in turn, be rotatably coupled to a generator shaft 36 of the generator 24 through a gearbox 38. As is generally understood, the rotor shaft 34 may provide a low' speed, high torque input to the701060-WO-1 / GECW-1285-PCT gearbox 38 in response to rotation of the rotor blades 22 and the hub 20. The gearbox 38 may then be configured to convert the low speed, high torque input to a high speed, low torque output to drive the generator shaft 36 and, thus, the generator 24.

[0031] The wind turbine 10 may also include one or more pitch drive mechanisms 32 communicatively coupled to the wind turbine controller 26, with each pitch adjustment mechanism(s) 32 being configured to rotate a pitch bearing 40 and thus the individual rotor blade(s) 22 about its respective pitch axis 28. In addition, as shown, the wind turbine 10 may include one or more yaw drive mechanisms 42 configured to change the angle of the nacelle 16 relative to the wind (e.g., by engaging a yaw bearing 44 of the wind turbine 10 that is arranged between the nacelle 16 and the tower 12 of the wind turbine 10).

[0032] In addition, the wind turbine 10 may also include one or more sensors 66 for monitoring various wind conditions of the wind turbine 10. For example, the incoming wind direction 52, wind speed, or any other suitable wind condition near of the wind turbine 10 may be measured, such as through use of a suitable weather sensor 66. Suitable weather sensors may include, for example, light detection and ranging devices, sonic detection and ranging devices, anemometers, wind vanes, barometers, radio detection and ranging devices or any other sensing device which can provide wind directional information now known or later developed in the art. Still further sensors 66 may be utilized to measure additional operating parameters of the wind turbine 10, such as voltage, current, vibration, etc. as described herein.

[0033] Referring now to FIG. 4, a schematic diagram of an embodiment of a wind turbine power system 100 is illustrated in accordance with aspects of the present disclosure. Although the present disclosure will generally be described herein with reference to the system 100 shown in FIG. 4, those of ordinary skill in the art, using the disclosures provided herein, should understand that aspects of the present disclosure may also be applicable in other power generation systems, and, as mentioned above, that the invention is not limited to wind turbine systems.

[0034] In the embodiment of FIG. 4 and as mentioned, the rotor 18 of the wind turbine 10 (FIG. 2) may, optionally, be coupled to the gearbox 38, which is, in turn, coupled to a generator 102, which may be a doubly fed induction generator (DFIG). As shown, the generator 102 may be connected to a stator bus 104. Further, as701060-WD-1 / GECW-1285-PCT shown, a pow er converter 106 may be connected to the generator 102 via a rotor bus 108, and to the stator bus 104 via a line side bus 110. As such, the stator bus 104 may provide an output multiphase power (e.g., three-phase power) from a stator of the generator 102, and the rotor bus 108 may provide an output multiphase power (e.g., three-phase pow er) from a rotor of the generator 102. The power converter 106 may also include a rotor side converter (RSC) 112 and a line side converter (LSC) 114. The generator 102 is coupled via the rotor bus 108 to the rotor side converter 112. Additionally, the RSC 112 is coupled to the LSC 114 via a DC link 116 across which is a DC link capacitor 118. The LSC 114 is, in turn, coupled to the line side bus 110.

[0035] The RSC 112 and the LSC 114 may be configured for normal operating mode in a three-phase, pulse width modulation (PWM) arrangement using one or more switching devices, such as insulated gate bipolar transistor (IGBT) switching elements. In addition, the power converter 106 may be coupled to a converter controller 120 in order to control the operation of the rotor side converter 112 and / or the line side converter 114 as described herein. It should be noted that the converter controller 120 may be configured as an interface between the power converter 106 and the turbine controller 26 and may include any number of control devices.

[0036] In typical configurations, various line contactors and circuit breakers including, for example, a grid breaker 122 may also be included for isolating the various components as necessary’ for normal operation of the generator 102 during connection to and disconnection from a load, such as the power grid 124. For example, a system circuit breaker 126 may couple a system bus 128 to a transformer 130, which may be coupled to the power grid 124 via the grid breaker 122. In alternative embodiments, fuses may replace some or all of the circuit breakers.

[0037] In operation, alternating current power generated at the generator 102 by rotating the rotor 18 is provided to the power grid 124 via dual paths defined by the stator bus 104 and the rotor bus 108. On the rotor bus side 108, sinusoidal multiphase (e.g., three-phase) alternating current (AC) power is provided to the power converter 106. The rotor side converter 112 converts the AC power provided from the rotor bus 108 into direct current (DC) power and provides the DC power to the DC link 116. As is generally understood, switching elements (e.g., IGBTs) used in the bridge circuits of the rotor side converter 112 may be modulated to convert the701060-WD-1 / GECW-1285-PCTAC power provided from the rotor bus 108 into DC power suitable for the DC link 116.

[0038] In addition, the line side converter 114 converts the DC power on the DC link 116 into AC output power suitable for the power grid 124. In particular, switching elements (e.g., IGBTs) used in bridge circuits of the line side converter 114 can be modulated to convert the DC power on the DC link 116 into AC power on the line side bus 110. The AC power from the power converter 106 can be combined with the power from the stator of generator 102 to provide multi-phase power (e.g., three-phase power) having a frequency maintained substantially at the frequency of the power grid 124 (e.g., 50 Hz or 60 Hz).

[0039] Additionally, various circuit breakers and switches, such as grid breaker 122, system circuit breaker 126, stator sync switch 132, converter breaker 134, and line contactor 136 may be included in the wind turbine power system 100 to connect or disconnect corresponding buses, for example, when current flow is excessive and may damage components of the wind turbine power system 100 or for other operational considerations. Additional protection components may also be included in the wind turbine power system 100.

[0040] Moreover, the power converter 106 may receive control signals from, for instance, the local control system via the converter controller 120. The control signals may be based, among other things, on sensed states or operating characteristics of the wind turbine power system 100. Typically, the control signals provide control of the operation of the power converter 106. For example, feedback in the form of a sensed speed of the generator 102 may be used to control the conversion of the output pow er from the rotor bus 108 to maintain a proper and balanced multi-phase (e.g., three- phase) power supply. Other feedback from other sensors may also be used by the controller(s) 120, 26 to control the power converter 106, including, for example, stator and rotor bus voltages and current feedbacks. Using the various forms of feedback information, switching control signals (e.g., gate timing commands for IGBTs), stator synchronizing control signals, and circuit breaker signals may be generated.

[0041] The power converter 106 also compensates or adjusts the frequency of the three-phase powder from the rotor for changes, for example, in the wind speed at the hub 20 and the rotor blades 22. Therefore, mechanical and electrical rotor frequencies701060-WO-1 / GECW-1285-PCT are decoupled, and the electrical stator frequency is substantially independent of the mechanical rotor speed.

[0042] Under some states, the bi-directional characteristics of the power converter 106, and specifically, the bi-directional characteristics of the LSC 114 and RSC 112, facilitate feeding back at least some of the generated electrical power into the generator rotor. More specifically, electrical power may be transmitted from the stator bus 104 to the line side bus 110 and subsequently through the line contactor 136 and into the power converter 106, specifically the LSC 114 which acts as a rectifier and rectifies the sinusoidal, three-phase AC power to DC power. The DC power is transmitted into the DC link 116. The capacitor 118 facilitates mitigating DC link voltage amplitude variations by facilitating mitigation of a DC ripple sometimes associated with three-phase AC rectification.

[0043] The DC power is subsequently transmitted to the RSC 112 that converts the DC electrical power to a three-phase, sinusoidal AC electrical power by adjusting voltages, currents, and frequencies. This conversion is monitored and controlled via the converter controller 120. The converted AC power is transmitted from the RSC 112 via the rotor bus 108 to the generator rotor. In this manner, generator active and reactive power control, or other controls, are facilitated by controlling rotor current and voltage.

[0044] Referring now to FIG. 5, the wind turbine power system 100 described herein may be part of a wind farm 50. As shown, the wind farm 50 may include a plurality of wind turbines 52, including the wind turbine 10 described above, and an overall farm-level controller 56. For example, as shown in the illustrated embodiment, the wind farm 50 includes twelve wind turbines, including wind turbine 10. However, in other embodiments, the wind farm 50 may include any other number of wind turbines, such as less than twelve wind turbines or greater than twelve wind turbines. In an embodiment, the turbine controllers of the plurality of wind turbines 52 are communicatively coupled to the farm-level controller 56, e.g., through a wired connection, such as by connecting the turbine controller 26 through suitable communicative links 54 (e g., a suitable cable). Alternatively, the turbine controllers may be communicatively coupled to the farm-level controller 56 through a wireless connection, such as by using any suitable wireless communications protocol known in701060-WO-1 / GECW-1285-PCT the art. In further embodiments, the farm-level controller 56 is configured to send and receive control signals to and from the various wind turbines 52, such as for example, distributing real and / or reactive power demands or voltage reference command signals across the wind turbines 52 of the wind farm 50.

[0045] Referring now to FIG. 6, a block diagram of an embodiment of suitable components that may be included within the controller (such as any one of the converter controller 120. the turbine controller 26. and / or the farm-level controller 56 described herein) in accordance with example aspects of the present disclosure is illustrated. As shown, the controller may include one or more processor(s) 58, computer, or other suitable processing unit and associated memory device(s) 60 that may include suitable computer-readable instructions that, when implemented, configure the controller to perform various different functions, such as receiving, transmitting and / or executing wind turbine control signals (e.g., performing the methods, steps, calculations and the like disclosed herein).

[0046] As used herein, the term "‘processor” refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits. Additionally, the memory' device(s) 60 may generally comprise memory' element(s) including, but not limited to, computer readable medium (e.g., random access memory’ (RAM)), computer readable non-volatile medium (e.g., a flash memory7), a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disc (DVD) and / or other suitable memory' elements.

[0047] Such memory device(s) 60 may generally be configured to store suitable computer-readable instructions that, when implemented by the processor(s) 58. configure the controller to perform various functions as described herein. Additionally, the controller may also include a communications interface 62 to facilitate communications betw een the controller and the various components of the wind turbine 10. An interface can include one or more circuits, terminals, pins, contacts, conductors, or other components for sending and receiving control signals. Moreover, the controller may include a sensor interface 64 (e.g., one or more analog- to-digital converters) to permit signals transmitted from the sensors 66 to be converted701060-WO-1 / GECW-1285-PCT into signals that can be understood and processed by the processor(s) 58.

[0048] Referring now to FIGS. 7 and 8, schematic diagrams of embodiments of a GFM power system 200. 300 according to the present disclosure are shown. In particular, as shown in each of FIGS. 7 and 8, the GFM power system 200, 300 may include many of the same features of FIG. 4 described herein, with components having the same reference characters representing like components. Further, as shown in each of FIGS. 7 and 8, the GFM power system 200. 300 may include a control structure for controlling the line side converter that is similar to the control structure shown in FIG. 1. More particularly, as shown in FIGS. 7 and 8, the line side converter control structure may include a DC voltage regulator 212 and a line current regulator 214. The DC voltage regulator 212 is configured to generate line-side current command signals for the line current regulator 214. The line current regulator 214 then generates line-side voltage command signals for a modulator 218. The modulator 218 also receives an output (e.g., a phase-locked loop angle) from a phase- locked loop 216 to generate one or more gate pulses for the line side converter 114. The phase-locked loop 216 typically generates its output using a voltage feedback signal.

[0049] Furthermore, as shown in FIGS. 7 and 8, the GFM powder system 200, 300 may also include a unique control structure for controlling the rotor side converter 112 using GFM characteristics. In particular, as shown in FIGS. 7 and 8. the GFM power system 200, 300 may include a stator voltage regulator 206 for providing such GFM characteristics. In addition, as shown in FIGS. 7 and 8, the GFM power system 200, 300 may include a grid voltage / VAR regulator 202, an inertial pow er regulator 204, a rotor current regulator 208, and a modulator 210. Further, as shown in FIGS. 7 and 8, the output from the stator voltage regulator 206 is a command signal for rotor current, which is implemented in the rotor current regulator 208 by generating rotor voltage command signals (VRCmdx and VRCmdy) for the modulator 210.

[0050] Moreover, as shown in FIGS. 7 and 8, the GFM power system 200, 300 further includes an error correction model 400, 500 configured to output an angle correction factor (GCORR), as discussed further below. In the embodiment shown in FIG. 7, as an example, the GFM powder system 200 may correct a rotor position feedback signal (0Fbk) with the angle correction factor (GCORR). In particular, as701060-WO-1 / GECW-1285-PCT shown in FIG. 7, a corrected rotor position feedback signal (0RFBK) may be determined by combining (e.g., via a summator 220) the angle correction factor (QRCORR) and the rotor position feedback signal (0FBK). AS such, the modulator 210 may receive the phase-locked loop angle from the phase-locked loop 216 and the corrected rotor position feedback signal (0RFbk) to generate one or more gate pulses for the rotor-side converter 112. The rotor position feedback signal (0FBK) may, for example, be measured by the one or more sensors 66 (e.g., a tachometer, an encoder, or any other suitable sensor configured to monitor the rotor shaft 34), as shown.

[0051] In the embodiment shown in FIG. 8, the GFM power system 300 may correct a rotor command signal with the angle correction factor (0CORR). In general, the GFM power system 300 is described herein with reference to the rotor command signal comprising rotor current command signals (IRCmdx and IRCmdy). However, it should be appreciated that the disclosed GFM power system 300 may be implemented with reference to the rotor command signal comprising rotor voltage command signals (VRCmdx and VRCmdyy). In particular, as shown in FIG. 8, the GFM power system 300 may include a rotor command correction model 302 that receives the rotor current command signal (IRCmdx and IRCmdy) and the angle correction factor (0CORR). The rotor command correction model 302 may be configured to correct the rotor current command signal (IRCmdx and IRCmdy) by rotating the rotor current command signal (IRCmdx and IRCmdy) based on the angle correction factor (0CORR) (e.g., according to known signal rotation techniques, such as applying an exp(j*Th) to complex variables or a rotation matrix in vector form). As such, the rotor command correction model 302 may be configured to output a corrected rotor current command signal (IRCmdxr and IRCmdyr) to the rotor current regulator 208, which generates the rotor voltage command signals (VRCmdx and VRCmdy) for the modulator 210, as shown.

[0052] More particularly, the GFM power system 200, 300 includes an inner-loop current-regulator structure and a fast stator voltage regulator to convert voltage command signals from the GFM controls to rotor current regulator command signals. Thus, the system and method of the present disclosure provide control of the rotor voltage of the generator 102 to meet a higher-level command for magnitude and angle of stator voltage. Such control must be relatively fast and insensitive to current701060-WO-1 / GECW-1285-PCT flowing in the stator of the generator 102.

[0053] Referring now to FIG. 9, the present disclosure is directed to a method 250 and for controlling the generator 102. In particular. FIG. 9 illustrates a flow diagram of an embodiment of the method 250 for controlling the generator 102 based on a corrected rotor signal according to the present disclosure is illustrated. In general, the method 250 is described herein with reference to the wind turbine 10 and the wind farm 50 of FIGS. 2-8. However, it should be appreciated that the disclosed method 250 may be implemented with any inverter-based resources in addition to wind turbines having any other suitable configurations. In addition, although FIG. 9 depicts steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement. One skilled in the art, using the disclosures provided herein, will appreciate that various steps of the methods disclosed herein can be omitted, rearranged, combined, and / or adapted in various ways without deviating from the scope of the present disclosure.

[0054] As shown at (252). the method 250 includes receiving, via a controller (such as any of the controllers 26, 56, 120 described herein) an actual generator signal associated with a reference signal or a command signal of the generator 102. In an embodiment, the actual generator signal may be a stator electrical angle command signal (SDPLL) (FIG. 10). In such an embodiment, the controller may receive the stator electrical angle command signal (SDPI.I.) from the inertial power regulator. In another embodiment, the actual generator signal may be a reference magnetizing impedance angle signal (ZmAngRef) (FIG. 11). In such an embodiment, the reference magnetizing impedance angle signal (ZmAngRef) may be determined from equivalent circuit information available on the generator design datasheets.

[0055] Referring still to FIG. 9, as shown at (254), the method 250 includes determining, via the controller, an expected generator signal associated with the actual generator signal based, at least in part, on a plurality of electrical feedback signals. For example, the expected generator signal may be derived from the plurality of electrical feedback signals (and combined according to known circuit analysis techniques).

[0056] In certain embodiments, the plurality of electrical feedback signals701060-WO-1 / GECW-1285-PCT includes a stator voltage feedback (V SFbkxy ). a stator current feedback (ISFbkxy), a rotor current feedback signal (IRfbkxy), a phase lock loop frequency signal (COPLL), a combination thereof, and / or any other suitable electrical feedback signal. The electrical feedback signal(s) may be measured by the one or more sensors 66 and / or determined by (e.g., according to known mathematical techniques) one or more controllers 26, 56, 120 (e.g., based on measurements received from the one or more sensors 66). As mentioned above, the expected generator signal is associated with the actual generator signal. For example, when the actual generator signal is the stator electrical angle command signal (SDPLL), the expected generator signal is an expected stator electrical angle signal (EdAngPred) (FIG. 10). As another example, when the actual generator signal is the magnetizing impedance angle feedback signal (ZmAngFbk), the expected generator signal is an expected reference magnetizing impedance angle signal (ZmAngRef) (FIG. 11).

[0057] Referring still to FIG. 9, as shown at (256), the method 250 includes determining, via the controller, an error signal based on a difference between the expected generator signal and the actual generator signal. The error signal is representative of a rotor position error w ith respect to a synchronous reference frame. As shown at (258), the method 250 includes correcting a rotor signal associated with a command signal or a feedback signal of the rotor based on the error signal. For example, as show n in FIG. 7, the rotor signal may be the rotor position feedback signal (0FBK). In such an embodiment, the rotor signal may be corrected by combining (e.g., via summation) the angle correction factor (GCOR ) and the rotor signal, as discussed above. As another example, as shown in FIG. 8, the rotor signal may be a rotor current command signal (IRCmdx and IRCmdy). In such an embodiment, the rotor signal may be corrected by rotating the rotor signal based on the angle correction factor (GCORR), as shown above.

[0058] Moreover, in embodiments, the angle correction factor (GCORR) may be determined based on the error signal. For example, in embodiments, an output representing a rate of change of the error signal may be determined based on the error signal, as described further below. Furthermore, the angle correction factor (GRCOR ) may be determined based on the output, as described further below. The method 250 may further include limiting the angle correction factor (GRCORR) by at least one of an701060-WO-1 / GECW-1285-PCT upper limit and a lower limit.

[0059] Referring still to FIG. 9, as shown at (260), the method 250 includes controlling, via the controller, the generator 102 based on the corrected rotor signal. For example, the corrected rotor position feedback signal (0RFBK) may be input to the modulator 210, as shown in FIG. 7. As another example, the corrected rotor current command signal (IRCmdx and IRCmdy) may be input to the rotor current regulator 208, as shown in FIG. 8. That is, the modulator 210 may receive a command signal or a feedback signal that is determined based on the corrected rotor signal, such that the gate pulse(s) output by the modulator 210 account for the error signal.

[0060] The method 250 of FIG. 9 can be better understood with reference to FIGS. 10-11. In particular, FIGS. 10-11 illustrate schematic diagrams of an error correction calculation model 400, 500 for controlling the generator 102 according to the present disclosure. More specifically, FIG. 10 illustrates a schematic diagram of an embodiment of an error correction calculation module 400 for operating the generator 102 based on an actual generator signal associated with a command signal of the generator 102 according to the present disclosure. FIG. 11 illustrates a schematic diagram of an embodiment of a schematic diagram of an embodiment of an error correction calculation module 500 for operating the generator 102 based on an actual generator signal associated with a reference signal of the generator 102 according to the present disclosure.

[0061] As shown in the embodiment illustrated in FIG. 10, the error correction calculation model 400 may be configured to determine the angle correction factor (ORCORR) based on a command signal of the generator 102. In general, the error correction calculation model 400 is described herein with reference to the command signal being a stator electrical angle command signal (SDPLL). However, it should be appreciated that the disclosed error correction calculation model 400 may be implemented using other command signals.

[0062] More specifically, as shown, the error correction calculation model 400 may receive the stator electrical angle command signal (SDPLL) from a line side power compensation module 402. The line side power compensation 402 may be configured to convert an angle command (8,T) associated with the total power output to the stator electrical angle command signal (SDPLL) associated with the stator power output, as701060-WO-1 / GECW-1285-PCT shown. This conversion may be carried out by estimating the power injection from the line-converter based on the speed feedback of the generator and the power output. By having the estimated line-converter power, the power angle associated with the total pow er output may be compensated to remove the effects of line-converter power injection. Moreover, as shown, the line side power compensation 402 may receive the angle command (5,T) from the inertial power regulator 204. Further, the inertial power regulator 204 may receive a power reference signal (Power Ref) from an external controller (e.g., the turbine controller 26). The inertial powder regulator 204 may include frequency droop (not shown) and an inertial regulator (not shown) configured to produce a desired frequency and angle of a voltage based on the power reference signal (Power_Ref). Further, the inertial power regulator 204 may determine the angle command (8,T) by comparing the desired frequency of the voltage to a phase lock loop frequency signal (COPLL), which represents the actual frequency of the external grid.

[0063] The stator electrical angle command signal (5DPLL) and an expected stator electrical angle signal (EdAngPred) are then compared, as shown at comparator 404, to obtain an error signal (EdAngErr). In this embodiment, the error correction calculation model 400 is configured to determine the expected stator electrical angle signal (EdAngPred) based on the plurality of electrical feedback signals. More specifically, as shown, the plurality of electrical feedback signals includes the stator voltage feedback signal (VSFbkxy), the stator current feedback signal (ISFbkxy) and the phase lock loop frequency signal (COPLL). In such an embodiment, the error correction calculation model 400 may be configured to determine a reactance (X) by applying (e.g., via multiplication) a conversion factor (C PLL ©base), as shown at 406, using the phase lock loop frequency signal (C PLL). That is, the conversion factor may specify the reactance (X) as a function of the phase lock loop frequency. The reactance (X) is then applied (e.g., via multiplication) to the stator current feedback signal (ISFbkxy), as shown at 408. to obtain an output 410 that represents a voltage drop across the impedance. The reactance shown at 408 could be, in another embodiment, replaced by a complex impedance with reactance (X) and resistance (R) terms. The output 410 and the stator voltage feedback signal (VSFbkxy) are combined (e.g., summed), as shown at 412, to obtain a predicted internal voltage (ElPred). An701060-WG-1 / GECW-1285-PCT arctangent function 414 is then applied to the predicted internal voltage (ElPred) to obtain the expected stator electrical angle signal (EdAngPred). More specifically, the arctangent function 414 is applied according to Equation (1) below:where ElPredxis an x-component of the predicted internal voltage (ElPred), and ElPredy is a y-component of the predicted internal voltage (ElPred) such that, in complex notation, ElPred = ElPredx+ j * ElPredy.

[0064] The error calculation correction model 400 is configured to apply a proportional-integral (PI) control 416 to the error signal (EdAngErr) to obtain an output 422. The output 422 represents a rate of change of the error signal (EdAngErr). The error calculation correction model 400 may be further configured to apply one or more constraints on the output 422. For example, the constraint(s) may include an upper limit 418 and / or a lower limit 420. In the embodiment shown in FIG. 10, the output 422 is constrained by an upper limit 418 and a lower limit 420 that are configured to constrain how fast the correction angle changes. For example, it may be undesirable to rapidly change the angle correction as a consequence of grid faults. The upper limit 418 and the low er limit 420 of the output 422 may be fixed variables or dynamic. Further, the gains of the PI regulator 416 may be fixed or dynamic and potentially change polarity based on operating conditions (e.g. over- or under-excited operation).

[0065] The output 422 is then integrated via integrator 424 to obtain the angle correction factor (GRCORR). The error calculation correction model 400 may be further configured to apply one or more constraints on the angle correction factor (GRCORR). For example, the constraint(s) may include an upper limit 426 and / or a low er limit 428. In the embodiment shown in FIG. 10, the angle correction factor (GRCORR) is constrained by an upper limit 426 and a lower limit 428 that are configured to constrain the angle correction within the normal range of expected error in rotor position. The upper limit 426 and the lower limit 428 of the angle correction factor (GRCORR) may be fixed or dynamic variables.

[0066] As shown in the embodiment illustrated in FIG. 11, the error correction calculation model 500 may be configured to determine the angle correction factor701060-WO-1 / GECW-1285-PCT(ORCORR) based on a reference signal of the generator 102. In general, the error correction calculation model 500 is described herein with reference to the reference signal being a reference magnetizing impedance angle signal (ZmAngRef). However, it should be appreciated that the disclosed error correction calculation model 500 may be implemented using other reference signals.

[0067] More specifically, as shown, the error correction calculation model 500 may receive the reference magnetizing impedance angle signal (ZmAngRef). The reference magnetizing impedance angle signal (ZmAngRef) may, for example, be stored in the controller (e.g., the memory devices 162 thereof). The reference magnetizing impedance angle signal (ZmAngRef) may, for example, be determined based on equivalent circuit parameters of the generator 102. As such, the controller may store (e.g., in the memory devices thereof) a look-up table, or the like, that associates various magnetizing impedance angles associated with corresponding operating conditions of the generator 102. Thus, the controller may access the lookup table to select the reference magnetizing impedance angle signal (ZmAngRef) (e.g., based on current operating conditions of the generator 102) and provide the reference magnetizing impedance angle signal (ZmAngRef) to the error correction calculation model 500.

[0068] The reference magnetizing impedance angle signal (ZmAngRef) and a magnetizing impedance angle feedback signal (ZMmAngFbk) are compared, as shown at comparator 502, to obtain an error signal (ZmAngErr). In this embodiment, the error correction calculation method 500 is configured to correct an error in rotor position with respect to a synchronous reference frame based on the plurality of electrical feedback signals, as shown at 504. More specifically, as shown, the plurality of electrical feedback signals includes the stator voltage feedback signal (VSFbkxy), the stator current feedback signal (ISFbkxy) and the rotor current feedback signal (IRFbkxy). In such an embodiment, the error correction calculation model 500 may be configured to determine the magnetizing impedance signal (ZmFbk) according to Equation (2) below:where Vs is a stator voltage,701060-WO-1 / GECW-1285-PCTIs is the stator current,Ir is the rotor current, andXs is the stator reactance, where each of these variables are written in complex notation such that each variable comprises a real and imaginary component.

[0069] An arctangent function 506 is then applied to the magnetizing impedance signal (ZmFbk) to obtain the magnetizing impedance angle signal (ZmAngFbk). More specifically, the arctangent function 506 is applied according to Equation (3) below:where ZmFbkxis an x-component of the magnetizing impedance (ZMmAngFbk), andZmAngFbkyis a y-component of the magnetizing impedance angle (ZMFbk).

[0070] The error calculation correction model 500 is configured to apply a proportional-integral (PI) control 508 to the error signal (ZmAngErr) to obtain an output 510. The output 510 represents a desired rate of change of the rotor angle correction signal (Orcorr). The error calculation correction model 500 is further configured to apply one or more constraints on the output 510. For example, the constraint(s) may include an upper limit 512 and / or a lower limit 514. In the embodiment shown in FIG. 11, the output 510 is constrained by an upper limit 512 and a lower limit 514 that are configured to constrain how fast the correction angle changes. For example, it may be undesirable to rapidly change the angle correction as a consequence of grid faults. The upper limit 512 and the lower limit 514 of the output 510 may be fixed variables or dynamic. Further, the gains of the PI regulator 508 may be fixed or dynamic and potentially change polarity based on operating conditions (e.g. over- or under-excited operation).

[0071] The output 510 is then integrated via integrator 516 to obtain the angle correction factor (ORCORR). The error calculation correction model 500 is further configured to apply one or more constraints on the angle correction factor (ORCORR). For example, the constraint(s) may include an upper limit 518 and / or a lower limit 520. In the embodiment shown in FIG. 11 , the angle correction factor (ORCORR) is constrained by an upper limit 518 and a lower limit 520 that are configured to701060-WO-1 / GECW-1285-PCT constrain the angle correction within the normal range of expected error in rotor position. The upper limit 518 and the lower limit 520 of the angle correction factor (QRCORR) may be fixed or dynamic variables.

[0072] Further aspects of the invention are provided by the subject matter of the following clauses:

[0073] A method for operating a generator of a grid-forming inverter-based resource, the generator having a rotor and a stator, the method comprising: receiving, via a controller, an actual generator signal associated with a reference signal or a command signal of the generator; determining, via the controller, an expected generator signal associated with the actual generator signal based, at least in part, on a plurality of electrical feedback signals; determining, via the controller, an error signal based on a difference between the expected generator signal and the actual generator signal, the error signal representative of a rotor position error with respect to a synchronous reference frame; correcting, via the controller, a rotor signal associated with a command signal or a feedback signal of the rotor based on the error signal; and controlling, via the controller, the generator based on the corrected rotor signal.

[0074] The method of any preceding clause, wherein the plurality of electrical feedback signals comprises at least one of a stator voltage feedback signal, a stator current feedback signal, a rotor current feedback signal, and a phase lock loop frequency signal.

[0075] The method of any preceding clause, wherein the rotor signal comprises a rotor position feedback signal.

[0076] The method of any preceding clause, wherein correcting the rotor signal based on the error signal further comprises: determining, via the controller, an angle correction factor based on the error signal; and combining, via the controller, the angle correction factor and the rotor position feedback signal.

[0077] The method of any preceding clause, wherein determining the angle correction factor based on the error signal further comprises: based on the error signal, determining, via the controller, an output configured to represent a rate of change of the error signal; and determining, via the controller, the angle correction factor based on the output.

[0078] The method of any preceding clause, further comprising limiting the angle701060-WO-1 / GECW-1285-PCT correction factor by at least one of an upper limit and a lower limit.

[0079] The method of any preceding clause, wherein the rotor signal comprises one of a rotor current command signal or a rotor voltage command signal.

[0080] The method of any preceding clause, wherein correcting the rotor signal based on the error signal further comprises: determining, via the controller, an angle correction factor based on the error signal; and rotating, via the controller, the one of the rotor current command signal or the rotor voltage command signal based on the angle correction factor.

[0081] The method of any preceding clause, wherein the actual generator signal comprises a stator electrical angle command signal, and wherein the expected generator signal comprises an expected stator electrical angle signal.

[0082] The method of any preceding clause, wherein the actual generator signal comprises a reference magnetizing impedance angle signal, and wherein the expected generator signal comprises an expected reference magnetizing impedance angle signal.

[0083] A wind turbine comprising: a generator having a rotor and a stator; and a controller comprising at least one processor, the at least one processor configured to perform a plurality of operations, the plurality of operations comprising: receiving an actual generator signal associated with a reference signal or a command signal of the generator; determining an expected generator signal associated with the actual generator signal based, at least in part, on a plurality of electrical feedback signals; determining an error signal based on a difference between the expected generator signal and the actual generator signal, the error signal representative of a rotor position error with respect to a synchronous reference frame; correcting a rotor signal associated with a command signal or a feedback signal of the rotor based on the error signal; and controlling the generator based on the corrected rotor signal.

[0084] The wind turbine of any preceding clause, wherein the plurality of electrical feedback signals comprises at least one of a stator voltage feedback signal, a stator current feedback signal, a rotor current feedback signal, and a phase lock loop frequency signal.

[0085] The wind turbine of any preceding clause, wherein the rotor signal comprises a rotor position feedback signal.701060-WO-1 / GECW-1285-PCT

[0086] The wind turbine of any preceding clause, wherein correcting the rotor signal based on the error signal further comprises: determining, via the controller, an angle correction factor based on the error signal; and combining, via the controller, the angle correction factor and the rotor position feedback signal.

[0087] The wind turbine of any preceding clause, wherein determining the angle correction factor based on the error signal further comprises: based on the error signal, determining, via the controller, an output configured to represent a rate of change of the error signal; and determining, via the controller, the angle correction factor based on the output.

[0088] The wind turbine of any preceding clause, wherein plurality of operations further comprises limiting the angle correction factor by at least one of an upper limit and a lower limit.

[0089] The wind turbine of any preceding clause, wherein the rotor signal comprises one of a rotor current command signal or a rotor voltage command signal.

[0090] The wind turbine of any preceding clause, wherein correcting the rotor signal based on the error signal further comprises: determining, via the controller, an angle correction factor based on the error signal; and rotating, via the controller, the one of the rotor current command signal or the rotor voltage command signal based on the angle correction factor.

[0091] The wind turbine of any preceding clause, wherein the actual generator signal comprises a stator electrical angle command signal, and wherein the expected generator signal comprises an expected stator electrical angle signal.

[0092] The wind turbine of any preceding clause, wherein the actual generator signal comprises a reference magnetizing impedance angle signal, and wherein the expected generator signal comprises an expected reference magnetizing impedance angle signal.

[0093] 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 include structural701060-WO-1 / GECW-1285-PCT 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

701060-WO-1 / GECW-1285-PCTWHAT IS CLAIMED IS:

1. A method for operating a generator of a grid-forming inverter-based resource, the generator having a rotor and a stator, the method comprising: receiving, via a controller, an actual generator signal associated with a reference signal or a command signal of the generator; determining, via the controller, an expected generator signal associated with the actual generator signal based, at least in part, on a plurality of electrical feedback signals; determining, via the controller, an error signal based on a difference between the expected generator signal and the actual generator signal, the error signal representative of a rotor position error with respect to a synchronous reference frame; correcting, via the controller, a rotor signal associated with a command signal or a feedback signal of the rotor based on the error signal; and controlling, via the controller, the generator based on the corrected rotor signal.

2. The method of claim 1, wherein the plurality of electrical feedback signals comprises at least one of a stator voltage feedback signal, a stator current feedback signal, a rotor current feedback signal, and a phase lock loop frequency signal.

3. The method of claim 1, wherein the rotor signal comprises a rotor position feedback signal.

4. The method of claim 3. wherein correcting the rotor signal based on the error signal further comprises: determining, via the controller, an angle correction factor based on the error signal; and combining, via the controller, the angle correction factor and the rotor position feedback signal.

5. The method of claim 4, wherein determining the angle correction701060-WO-1 / GECW-1285-PCT factor based on the error signal further comprises: based on the error signal, determining, via the controller, an output configured to represent a rate of change of the error signal; and determining, via the controller, the angle correction factor based on the output.

6. The method of claim 5, further comprising limiting the angle correction factor by at least one of an upper limit and a lower limit.

7. The method of claim 1, wherein the rotor signal comprises one of a rotor current command signal or a rotor voltage command signal.

8. The method of claim 7, wherein correcting the rotor signal based on the error signal further comprises: determining, via the controller, an angle correction factor based on the error signal; and rotating, via the controller, the one of the rotor current command signal or the rotor voltage command signal based on the angle correction factor.

9. The method of claim 1, wherein the actual generator signal comprises a stator electrical angle command signal, and wherein the expected generator signal comprises an expected stator electrical angle signal.

10. The method of claim 1, wherein the actual generator signal comprises a reference magnetizing impedance angle signal, and wherein the expected generator signal comprises an expected reference magnetizing impedance angle signal.

11. A wind turbine, comprising: a generator having a rotor and a stator; and a controller comprising at least one processor, the at least one processor configured to perform a plurality of operations, the plurality of operations comprising: receiving an actual generator signal associated with a reference signal or a command signal of the generator;701060-WO-1 / GECW-1285-PCT determining an expected generator signal associated with the actual generator signal based, at least in part, on a plurality of electrical feedback signals; determining an error signal based on a difference between the expected generator signal and the actual generator signal, the error signal representative of a rotor position error with respect to a synchronous reference frame; correcting a rotor signal associated with a command signal or a feedback signal of the rotor based on the error signal; and controlling the generator based on the corrected rotor signal.

12. The wind turbine of claim 11, wherein the plurality' of electrical feedback signals comprises at least one of a stator voltage feedback signal, a stator current feedback signal, a rotor current feedback signal, and a phase lock loop frequency signal.

13. The wind turbine of claim 11, wherein the rotor signal comprises a rotor position feedback signal.

14. The wind turbine of claim 13, wherein correcting the rotor signal based on the error signal further comprises: determining, via the controller, an angle correction factor based on the error signal; and combining, via the controller, the angle correction factor and the rotor position feedback signal.

15. The wind turbine of claim 14, wherein determining the angle correction factor based on the error signal further comprises: based on the error signal, determining, via the controller, an output configured to represent a rate of change of the error signal; and determining, via the controller, the angle correction factor based on the output.

16. The wind turbine of claim 15, wherein plurality of operations further comprises limiting the angle correction factor by at least one of an upper limit and a701060-WO-1 / GECW-1285-PCT lower limit.

17. The wind turbine of claim 11, wherein the rotor signal comprises one of a rotor current command signal or a rotor voltage command signal.

18. The wind turbine of claim 17, wherein correcting the rotor signal based on the error signal further comprises: determining, via the controller, an angle correction factor based on the error signal; and rotating, via the controller, the one of the rotor current command signal or the rotor voltage command signal based on the angle correction factor.

19. The wind turbine of claim 11, wherein the actual generator signal comprises a stator electrical angle command signal, and wherein the expected generator signal comprises an expected stator electrical angle signal.

20. The wind turbine of claim 11, wherein the actual generator signal comprises a reference magnetizing impedance angle signal, and wherein the expected generator signal comprises an expected reference magnetizing impedance angle signal.

Images