System and method for providing grid-forming control of an inverter-based resource

Abstract

A method for providing grid forming control of an inverter-based resource (IBR) includes calculating an expected operating point based on a power command signal or an indication of grid frequency, dynamically determining at least one margin signal for an inertial power regulator of the IBR and calculating one or more controller limits for the inertial power regulator based on the expected operating point and / or the margin signal(s). The margin signal is reduced when the IBR experiences nonlinear operation, equipment limits of the IBR are approached or exceeded, or allowable grid induced power deviations are approached or exceeded. The method also includes operating the inertial power regulator based on the controller limit(s). By reducing the margin signal(s) when the IBR experiences the nonlinear operation, the equipment limit(s) of the IBR are approached or exceeded, or the allowable grid induced power deviations are approached or exceeded, the controller limit(s) is constrained within an expected operating range of the inertial power regulator.

Description

609026-WO-1 / GECW-1237-PCT SYSTEM AND METHOD FOR PROVIDING GRID-FORMING CONTROL OF AN INVERTER-BASED RESOURCE FIELD

[0001] The present disclosure relates generally to inverter-based resources, such as wind turbine power systems and, more particularly, to systems and methods for providing grid-forming control for inverter-based resources. 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 modern 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 profile 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 are609026-WO-1 / GECW-1237-PCT located in a weak grid, wind turbine power fluctuations may lead to an increase in magnitude and frequency variations in the grid voltage. These fluctuations may adversely affect the performance and stability of the PLL and wind turbine current control.

[0004] Many existing renewable generation converters, such as double-fed wind turbine generators, operate in a “grid-following” mode. 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 doubly fed 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 double-fed 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 load609026-WO-1 / GECW-1237-PCT 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 (1)-(5) without 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 Patent No.: 7,804,184 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.” Applications to grid-forming control for a doubly fed wind turbine generator are disclosed in PCT / US2020 / 013787 entitled “System and Method for Providing Grid- Forming Control for a Doubly-Feb Wind Turbine Generator.”

[0007] As an example, FIG.2 illustrates a schematic diagram of an embodiment of a main circuit of a grid-forming system. As shown, the main circuit includes a power electronic converter with connections on DC and AC sides. This converter receives gating commands from a controller that creates an AC voltage phasor Vcnv at an angle of Thvcnv. The angle is with respect to a reference phasor having a fixed frequency in steady state. The DC side is supplied with a device capable of generating or absorbing power for even a short duration. Such devices may include, for example, batteries, solar panels, rotating machines with a rectifier, or capacitors. In addition, as shown, the circuit includes an inductive impedance Xcnv connecting the converter to its point of interconnection, shown as the voltage Vt and angle ThVt in FIG.2. The electrical system behind the point of interconnect is shown as a Thevenin equivalent with impedance Zthev and voltage Vthev at angle ThVthev. This equivalent can be used to represent any circuit, including grid-connected and islanded circuits with loads. In practical situations, the impedance Zthev will be primarily inductive.

[0008] Still referring to FIG.2, the closed-loop portion of the main control609026-WO-1 / GECW-1237-PCT receives feedback signals from the voltage and current at the point of interconnection. Additional inputs are received from higher-level controls (not shown). While FIG.2 illustrates a single converter as an example, any grouping of equipment that can create an electrical equivalent of a controlled voltage Vcnv behind an impedance Xcnv can have the control schemes disclosed applied to achieve the same performance benefits.

[0009] Referring now to FIG.3, a control diagram for providing grid-forming control according to conventional construction is illustrated. As shown, a converter controller 1 receives references (e.g., Vref and Pref) and limits (e.g., VcmdLimits and PcmdLimits) from higher-level controls 2. These high-level limits are on physical quantities of voltage, current, and power. The main regulators include a fast voltage regulator 3 and a slow power regulator 4. These regulators 3, 4 have final limits applied to the converter control commands for voltage magnitude (e.g., VcnvCmd) and angle (e.g., θPang and θPLL) to implement constraints on reactive- and real- components of current, respectively.

[0010] Several common challenges are associated with grid forming power regulation, including regulator windup during controller nonlinear operation (e.g., overmodulation, current limiting, etc.) and equipment overload due to grid transients.

[0011] With respect to regulator windup challenges, the grid forming power regulator relies on a certain relationship between angle command and power to achieve the desired closed loop response. This relationship between the angle command and power may be slightly or severely corrupted during overmodulation conditions and / or dynamic brake (DB) operation, and / or may reach downstream control limits. When the angle / power relationship is corrupted, the power regulator may ‘windup’, meaning that the regulator exhibits limit cycle behavior (e.g., the regulator may oscillate in an uncontrolled manner between upper and lower control limits), or generally lose control of active power.

[0012] With respect to equipment overload challenges, the grid forming power regulator acts to support grid frequency / angle. Severe grid events or operating conditions where the grid forming inverter-based resource is close to power / energy limits (e.g., low operating speed) may cause equipment overload or tripping of the inverter-based resource.

[0013] In view of the foregoing, the present disclosure is directed to a system and609026-WO-1 / GECW-1237-PCT method that avoids undesirable regulator windup and equipment overloads while maximizing grid support by smoothly adjusting controller limits to a wide range when operating in conditions with low risk of windup / overload and a narrow range when operating in conditions with high risk of windup / overload. BRIEF DESCRIPTION

[0014] 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.

[0015] In an aspect, the present disclosure is directed to a method for providing grid forming control of an inverter-based resource. The method includes calculating at least one expected operating point based on a power command signal or an indication of grid frequency; dynamically determining at least one margin signal for an inertial power regulator of the inverter-based resource; calculating one or more controller limits for the inertial power regulator based on the at least one expected operating point and the at least one margin signal, wherein the at least one margin signal is reduced when the inverter-based resource experiences nonlinear operation, one or more equipment limits of the inverter-based resource are approached or exceeded, or allowable grid induced power deviations are approached or exceeded; and operating the inertial power regulator of the inverter-based resource based on the one or more controller limits, wherein by reducing the at least one margin signal when the inverter-based resource experiences the nonlinear operation, the one or more equipment limits of the inverter-based resource are approached or exceeded, or the allowable grid induced power deviations are approached or exceeded, the one or more controller limits is constrained within an expected operating range of the inertial power regulator to avoid at least one of regulator windup, equipment overload, or excessive grid-induced power deviations.

[0016] In another aspect, the present disclosure is directed to a system for providing grid-forming control of an inverter-based resource. The system includes an inertial power regulator and at least one processor configured to perform a plurality of operations. The plurality of operations include, but are not limited to, calculating at least one expected operating point based on a power command signal or an indication609026-WO-1 / GECW-1237-PCT of grid frequency; dynamically determining at least one margin signal for the inertial power regulator; calculating one or more controller limits for the inertial power regulator based on the at least one expected operating point and the at least one margin signal, wherein the at least one margin signal is reduced when the inverter- based resource experiences nonlinear operation, one or more equipment limits of the inverter-based resource are approached or exceeded, or allowable grid induced power deviations are approached or exceeded; and operating the inertial power regulator of the inverter-based resource based on the one or more controller limits, wherein by reducing the at least one margin signal when the inverter-based resource experiences the nonlinear operation, the one or more equipment limits of the inverter-based resource are approached or exceeded, or the allowable grid induced power deviations are approached or exceeded, the one or more controller limits is constrained within an expected operating range of the inertial power regulator to avoid at least one of regulator windup, equipment overload, or excessive grid-induced power deviations.

[0017] 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

[0018] 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:

[0019] FIG.1 illustrates a one-line diagram of a double-fed wind turbine generator with structure of converter controls for grid-following application according to conventional construction;

[0020] FIG.2 illustrates a schematic diagram of an embodiment of a main circuit of a grid-forming system according to conventional construction;

[0021] FIG.3 illustrates a control diagram for providing grid-forming control according to conventional construction;

[0022] FIG.4 illustrates a perspective view of an embodiment of a wind turbine609026-WO-1 / GECW-1237-PCT according to the present disclosure;

[0023] FIG.5 illustrates a simplified, internal view of an embodiment of a nacelle according to the present disclosure;

[0024] FIG.6 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;

[0025] FIG.7 illustrates a schematic view of an embodiment of a wind farm having a plurality of wind turbines according to the present disclosure;

[0026] FIG.8 illustrates a block diagram of an embodiment of a controller according to the present disclosure;

[0027] FIG.9 illustrates a flow diagram of an embodiment of a method for providing grid-forming control of an inverter-based resource according to the present disclosure;

[0028] FIG.10 illustrates a control diagram of an embodiment of a system for providing grid-forming control of an inverter-based resource according to the present disclosure;

[0029] FIG.11 illustrates a control diagram of an embodiment of an anti-windup and grid transient overload limit module of a system for providing grid-forming control of an inverter-based resource according to the present disclosure; and

[0030] FIG.12 illustrates a control diagram of an embodiment of directional limit margin signals in the positive direction for a system for providing grid-forming control of an inverter-based resource according to the present disclosure. DETAILED DESCRIPTION

[0031] Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is 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.609026-WO-1 / GECW-1237-PCT

[0032] In general, the present disclosure is directed to systems and methods for providing grid-forming control via an inverter-based resource in response to sudden changes in the grid, while also being able to rapidly limit power to stay within equipment ratings and to rapidly follow commands from higher-level controls. Thus, in certain embodiments, the rapid response to control commands is achieved with a feedforward path as well as an improved power limit function. Though the systems and methods of the present disclosure are described in general herein with respect to a wind turbine power system, it should be understood that the systems and methods can be applied to any other inverter-based resource.

[0033] Referring now to the drawings, FIG.4 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, a 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.5) positioned within the nacelle 16 to permit electrical energy to be produced.

[0034] 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 wind609026-WO-1 / GECW-1237-PCT 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.

[0035] Referring now to FIG.5, a simplified, internal view of an embodiment of the nacelle 16 of the wind turbine 10 shown in FIG.4 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 the 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.

[0036] The wind turbine 10 may also 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).

[0037] In addition, the wind turbine 10 may also include one or more sensors 66, 68 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 (“LIDAR”) devices, Sonic Detection and Ranging (“SODAR”) devices, anemometers, wind vanes, barometers, radar devices (such as Doppler radar devices) or any other sensing device which can provide wind directional information now known or later developed in the art. Still further sensors 68 may be utilized to609026-WO-1 / GECW-1237-PCT measure additional operating parameters of the wind turbine 10, such as voltage, current, vibration, etc. as described herein.

[0038] Referring now to FIG.6, 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 wind turbine 10 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.

[0039] In the embodiment of FIG.6 and as mentioned, the rotor 18 of the wind turbine 10 (FIG.4) 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, as shown, a power 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 power) 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.

[0040] 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.

[0041] In typical configurations, various line contactors and circuit breakers609026-WO-1 / GECW-1237-PCT 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 electrical 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 electrical grid 124 via the grid breaker 122. In alternative embodiments, fuses may replace some or all of the circuit breakers.

[0042] In operation, alternating current power generated at the GENERATOR 102 by rotating the rotor 18 is provided to the electrical grid 124 via dual paths defined by the stator bus 104 and the rotor bus 108. On the rotor bus side 108, sinusoidal multi- phase (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 the AC power provided from the rotor bus 108 into DC power suitable for the DC link 116.

[0043] In addition, the line side converter 114 converts the DC power on the DC link 116 into AC output power suitable for the electrical 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 electrical grid 124 (e.g., 50 Hz or 60 Hz).

[0044] 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 100.609026-WO-1 / GECW-1237-PCT

[0045] Moreover, the power converter 106 may receive control signals from, for instance, the local control system 176 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 control 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 power 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.

[0046] The power converter 106 also compensates or adjusts the frequency of the three-phase power 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 frequencies are decoupled, and the electrical stator and rotor frequency matching is facilitated substantially independently of the mechanical rotor speed.

[0047] 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 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.

[0048] 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 RSC609026-WO-1 / GECW-1237-PCT 112 via the rotor bus 108 to the generator rotor. In this manner, generator reactive power control is facilitated by controlling rotor current and voltage.

[0049] Referring now to FIG.7, 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 in 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 across the wind turbines 52 of the wind farm 50.

[0050] Referring now to FIG.8, 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).

[0051] 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), an609026-WO-1 / GECW-1237-PCT application specific integrated circuit, and other programmable circuits. Additionally, the memory device(s) 60 may generally include 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 memory), 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.

[0052] 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 between 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, 68 to be converted into signals that can be understood and processed by the processor(s) 58.

[0053] Referring now to FIG.9, a flow diagram of an embodiment of a method 200 for providing grid-forming control of an inverter-based resource is provided. In general, the method 200 is described herein with reference to the wind turbine power system 100 of FIGS.4-8. However, it should be appreciated that the disclosed method 200 may be implemented with any other suitable power generation systems 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 (202), the method 200 includes calculating at least one expected operating point based on a power command signal or an indication of grid frequency. For example, in an embodiment, the expected operating point may be an angle command, a frequency command, a current command, or combinations thereof.

[0055] As shown at (204), the method 200 includes dynamically determining at609026-WO-1 / GECW-1237-PCT least one margin signal for an inertial power regulator of the inverter-based resource. As shown at (206), the method 200 includes calculating one or more controller limits for the inertial power regulator based on the expected operating point(s) and the margin signal(s), wherein the margin signal(s) is reduced when the inverter-based resource experiences nonlinear operation (e.g., overmodulation, current limiting, etc.), one or more equipment limits of the inverter-based resource are approached or exceeded, or allowable grid induced power deviations are approached or exceeded. For example, in an embodiment the controller limit(s) described herein may include a frequency minimum limit, a frequency maximum limit, an angle minimum limit, or an angle maximum limit.

[0056] Furthermore, in an embodiment, dynamically determining the margin signal(s) for the inverter-based resource may include dynamically determining a first margin signal around a frequency of a phase-locked loop (PLL) integrator of the inverter-based resource. More specifically, in an embodiment, dynamically determining the first margin signal around the frequency of the PLL integrator of the inverter-based resource may include receiving an indication of the inverter-based resource experiencing the nonlinear operation or the one or more equipment limits of the inverter-based resource being approached or exceeded and, in response to the indication, applying a scale factor to the first margin signal around the frequency of the PLL integrator of the inverter-based resource to reduce the first margin signal. In other embodiments, the margin signal may be reduced by directly adding or subtracting a margin reduction signal that is, for example, proportional to the severity of the non-linearity or equipment overload. In such an embodiment, this margin reduction signal is used instead of applying a scale factor but has a similar effect.

[0057] In further embodiments, dynamically determining the margin signal(s) for the inverter-based resource may include dynamically determining a second margin signal around a feedforward angle command associated with active power command of the inverter-based resource. Accordingly, in an embodiment, during normal operation, the second margin signal is maintained above a certain threshold to provide grid support and to avoid reaching regulator limits when not near the equipment limit(s). However, when the inverter-based resource experiences the nonlinear operation or the equipment limit(s) of the inverter-based resource are approached or609026-WO-1 / GECW-1237-PCT exceeded, the second margin signal is reduced to gradually reduce an amount the inertial power regulator adjusts the angle command away from the expected operating range. The expected operating range reflects, for example, the amount of deviation in inertial power regulator frequency and / or angle that is acceptable or reasonable for a given power reference and / or PLL frequency and considering the amount of dynamic grid frequency / angle support the IBR is capable of providing. Generally, as equipment limits, nonlinear operation, or allowable grid-induced power deviations are approached or exceeded, limited grid support capability is available or allowed by the IBR and tightening of the expected operating range can be beneficial to avoid regulator windup and / or preventing overload.

[0058] Referring still to FIG.9, as shown at (208), the method 200 includes operating the inertial power regulator of the inverter-based resource based on the one or more controller limits, wherein by reducing the at least one margin signal when the inverter-based resource experiences the nonlinear operation, the one or more equipment limits of the inverter-based resource are approached or exceeded, or the allowable grid induced power deviations are approached or exceeded, the one or more controller limits is constrained within an expected operating range of the inertial power regulator to avoid at least one of regulator windup, equipment overload, or excessive grid-induced power deviations.

[0059] The method 200 of FIG.9 can now be better understood with reference to the system 300 illustrated in FIGS.10-12. In particular, FIG.10 illustrates a control diagram of an embodiment of the system 300 for providing grid-forming control of an inverter-based resource. FIG.11 illustrates a control diagram of an embodiment of an anti-windup and grid transient overload limit module 358 of the system 300 according to the present disclosure.

[0060] As shown particularly in FIG.10, the system 300 may include many of the same features of FIG.3 described herein. More specifically, as shown, the system 300 of FIG.10 includes a unique power regulator 302 (as compared to the convention power regulator 4 of FIG.3). As shown, the system 300 receives a power reference 304 (e.g., Pref) and a power command limits 306 (e.g., PcmdLimits) from a higher-level controller (e.g., the turbine controller 26 and / or the farm-level controller 156). These higher-level limits are on physical quantities of voltage, current, and power.609026-WO-1 / GECW-1237-PCT

[0061] Thus, as shown, the power regulator 302 has final limits applied to converter gating control of the converter controller 120 (FIG.6) for power angle (e.g., θPang) to implement constraints on real components of current, respectively. In particular, as shown in FIG.10, the system 300 of the present disclosure provides rapid response to control commands using a feedforward path 308 and a power limit function 310. Moreover, as shown, the system 300 includes a phase-locked loop (PLL) 312.

[0062] Further, the converter gating control of FIG.10 is configured to create a converter voltage with an angle based upon the control signals 314, 316 (e.g., θPang and θPLL). In other embodiments, the voltage with angle based on θPang314 and θPLL316 may be created by other equipment capability of creating a voltage phasor. In particular embodiments, for example, the phase-locked loop 312 measures the angle θPLL 314, which in steady-state is equal to the angle θVt of the voltage Vt in the system. In such embodiments, these values are with respect to the system reference angle. During transients, an error signal 318 (e.g., θPLLerr) is generated in this measurement.

[0063] Moreover, the angle θPLLof the phase-locked loop 312 is the integral of the PLL frequency ωPLL, as shown in Equation (1) below: θPLL = 1 / s [ωPLL] Equation (1)

[0064] In addition, the power angle θPang from the power regulator 302 is the integral of the power regulator frequency less the PLL frequency ωPLL, as shown in Equations (2)-(3) below: θPang = 1 / s [ωPreg - ωPLL] Equation (2) θPang = 1 / s [ωPreg] – θPLL Equation (3)

[0065] The angle θVcnv of the converter voltage relative to the system reference is equal to integral of the power regulator frequency signal ωPreg and is independent of the PLL error, as shown in Equation (4) below:609026-WO-1 / GECW-1237-PCT θVcnv= 1 / s [ωPreg] Equation (4)

[0066] Accordingly, and referring still to FIG.10, to minimize latency to variations in the power command, the system 300 is configured to calculate a feedforward angle 320 (e.g., θPangff) in the feedforward path 308. Thus, as shown at 322, the feedforward angle 320 (e.g., in radians) can be differentiated to obtain an angle rate of change in frequency 324 (e.g., ωPangffwith units of radians / second). Further, as shown at 326, the angle rate of change in frequency 324 can then be summed with frequency signals 328, 330 (e.g., ωPrefand ωPLL) to obtain output 332. The output 332 of this summation can then be integrated via integrator 334 to obtain the power angle / control signal 314 (e.g., θPang). In addition, as shown, an angle rate of change in frequency 340 (e.g., ωPLLff) of the PLL 312 can be summed, as shown at 342, with the frequency signal 330 (e.g., ωPLL) to obtain an output 344. The output 344 can then be integrated via integrator 346 to obtain the control signal 316 (e.g., θPLL).

[0067] In additional embodiments, as shown in FIG.10, the power limit function 310 of the system 300 may also provide upper and lower power angle limits 336, 338 (e.g., θPangMaxand θPangMin) on the power angle / control signal 314 (e.g., θPang) across the converter reactance. Thus, the power angle limits 336, 338 are configured to provide a restraint on the power to prevent excess equipment overload while other regulators act to settle after a severe transient.

[0068] For example, in certain embodiments, the system 300 may include a feedforward power limiter 352 and the anti-windup and grid transient overload limit module 358. Thus, the feedforward power limiter 352 receives the power command limits 306 (e.g., PcmdLimits) and / or the error signal 318 (e.g., θPLLerr) from an external controller (e.g., the turbine controller 26 and / or the farm-level controller 156) and calculates power angle limits 354, 356 (e.g., θPangMax0 and θPangMin0) for the anti- windup and grid transient overload limit module 358. Further, as shown, the anti- windup and grid transient overload limit module 358 uses the power angle limits 354, 356 (e.g., θPangMax0 and θPangMin0) to calculate the upper and lower limits 336, 338 (e.g., θPangMax and θPangMin), as well as frequency limits 348, 350 (e.g., ωMax and ωMin).609026-WO-1 / GECW-1237-PCT

[0069] Referring now to FIG.11, a control diagram of an embodiment of the anti- windup and grid transient overload limit module 358 of the system 300 of FIG.10 is illustrated according to the present disclosure. In particular, as shown, in an embodiment, the anti-windup and grid transient overload limit module 358 is configured to dynamically determine the margin signal(s) for the inverter-based resource. In particular embodiments, as shown, the anti-windup and grid transient overload limit module 358 is configured to dynamically determine a first margin signal 364 around a frequency of a PLL integrator 366 (e.g., ωPllInt) of the inverter- based resource.

[0070] More specifically, in an embodiment, the anti-windup and grid transient overload limit module 358 is configured to dynamically determine the first margin signal 364 by receiving an indication of the inverter-based resource experiencing the nonlinear operation or the equipment limit(s) of the inverter-based resource being approached or exceeded. In particular, as shown, the anti-windup and grid transient overload limit module 358 is configured to receive a feedback signal 360 (e.g., R_UmagFbk) and compare the feedback signal 360 to a threshold 362. In response to the indication, the anti-windup and grid transient overload limit module 358 is further configured to apply a scale factor 368 (e.g., FrqAngMrgSF) to the first frequency margin signal 364 (e.g., ωPLLMrg0) around the frequency of the PLL integrator 366 (e.g., ωPllInt) to reduce the first frequency margin signal 364. In an embodiment, the first frequency margin signal 364 (e.g., ωPLLMrg0) is the predetermined frequency margin used for the limits when not operating in a non-linear region, equipment overload, etc. The upper frequency margin, when summed together with the frequency of the PLL integrator 366, gives a dynamic upper frequency limit for the inverter-based resource. This upper frequency limit is then constrained to the upper frequency design limit of the IBR (ωMax0) to give the final upper frequency limit ωMax 348. Similar calculations are performed for the lower frequency limit and lower frequency margin to give the final lower frequency limit ωMin 350.

[0071] Still referring to FIG.11, the anti-windup and grid transient overload limit module 358 is configured to dynamically determine a second margin signal 370 (e.g., θPangffMrg0) around the feedforward angle 320 (e.g., θPangff) associated with active power command of the inverter-based resource. In an embodiment, the second609026-WO-1 / GECW-1237-PCT margin signal 370 (e.g., θPangffMrg0) is the predetermined angle margin used for the angle limits when not operating in the non-linear region, equipment overload, etc. Accordingly, in an embodiment, during normal operation, the second margin signal 370 is maintained above a certain threshold to provide grid support and to avoid reaching regulator limits when not near the equipment limit(s). However, when the inverter-based resource experiences the nonlinear operation or the equipment limit(s) of the inverter-based resource are approached or exceeded (e.g., as indicated by feedback signal 360 being above threshold 362), the second margin signal 370 is reduced to gradually reduce an amount the inertial power regulator 305 adjusts the angle 314 away from the expected operating range. The upper angle margin, when summed together with the feedforward angle 320, gives a final dynamic upper angle limit for the inverter-based resource. This final upper angle limit (θPangMax 336) is then constrained to the upper angle limit associated with the feedforward power limiter (θPangMax0). Similar calculations are carried out for the lower angle margin and lower angle limit.

[0072]

[0073] Referring now to FIGS.11 and 12, directional limits 372, 374 (e.g., ωpllMrgLimH and θPangffMrgLimH) can also be applied to the frequency angle margin signals 364, 370. In particular, FIG.12 illustrates a schematic diagram 400 of an embodiment of the directional limits 372, 374 on the frequency / angle margin signals 364, 370 in the positive direction, i.e., being a positive value, is illustrated. In another embodiment, similar directional limits may also be applied in the negative direction, i.e., being a negative value. As certain equipment limits (e.g., speed (SpdFbk 404), active current (IxCmd 406), etc.) are approached (e.g., by comparing to respective thresholds 410, 412), the positive margin on power regulator frequency / angle is reduced since windup or overload risks primarily in the positive direction. DB operation (as determined by input DBPwr 402 compared to threshold 408) may cause the power regulator to compensate for power losses in the dynamic brake of the power converter 106. Directional limits to account for a DB operation limit how much the power regulator may compensate for DB operation. In other embodiments, though not shown in Fig.12, directional limits may be determined to constrain certain components of grid-induced power deviations in a certain direction. For example,609026-WO-1 / GECW-1237-PCT these grid-induced power deviations may be inertial power deviation caused by decreases in grid frequency or phase-jump power deviation cause by sudden changes in the grid phase angle. In such embodiments, these components of grid-induced power deviations may be estimated and used as inputs to the anti-windup and grid transient overload limit module 358.

[0074] Further aspects of the invention are provided by the subject matter of the following clauses:

[0075] A method for providing grid forming control of an inverter-based resource, the method comprising: calculating at least one expected operating point based on a power command signal or an indication of grid frequency; dynamically determining at least one margin signal for an inertial power regulator of the inverter-based resource; calculating one or more controller limits for the inertial power regulator based on the at least one expected operating point and the at least one margin signal, wherein the at least one margin signal is reduced when the inverter-based resource experiences nonlinear operation, one or more equipment limits of the inverter-based resource are approached or exceeded, or allowable grid induced power deviations are approached or exceeded; and operating the inertial power regulator of the inverter-based resource based on the one or more controller limits, wherein by reducing the at least one margin signal when the inverter-based resource experiences the nonlinear operation, the one or more equipment limits of the inverter-based resource are approached or exceeded, or the allowable grid induced power deviations are approached or exceeded, the one or more controller limits is constrained within an expected operating range of the inertial power regulator to avoid at least one of regulator windup, equipment overload, or excessive grid-induced power deviations.

[0076] The method of any preceding clause, further comprising receiving at least one of the power command signal or the indication of the grid frequency from an external controller.

[0077] The method of any preceding clause, wherein the expected operating point comprises at least one of an angle, frequency, current, or voltage.

[0078] The method of any preceding clause, wherein the one or more controller limits comprises at least one of a frequency minimum limit, a frequency maximum limit, an angle minimum limit, or an angle maximum limit.609026-WO-1 / GECW-1237-PCT

[0079] The method of any preceding clause, wherein dynamically determining the at least one margin signal for the inverter-based resource further comprises: dynamically determining a first margin signal around a frequency of a phase-locked loop (PLL) integrator of the inverter-based resource.

[0080] The method of any preceding clause, wherein dynamically determining the first margin signal around the frequency of the PLL integrator of the inverter-based resource further comprises: receiving an indication of the inverter-based resource experiencing the nonlinear operation or the one or more equipment limits of the inverter-based resource being approached or exceeded; and in response to the indication, applying a scale factor to the first margin signal around the frequency of the PLL integrator of the inverter-based resource to reduce the first margin signal.

[0081] The method of any preceding clause, wherein dynamically determining the at least one margin signal for the inverter-based resource further comprises: dynamically determining a second margin signal around a feedforward angle command associated with an active power command of the inverter-based resource.

[0082] The method of any preceding clause, wherein, during normal operation, the second margin signal is maintained above a certain threshold to provide grid support and to avoid reaching regulator limits when not near the one or more equipment limits, and wherein, when the inverter-based resource experiences the nonlinear operation or the one or more equipment limits of the inverter-based resource are approached or exceeded, the second margin signal is reduced to gradually reduce an amount an angle of the inertial power regulator deviates from the expected operating point.

[0083] The method of any preceding clause, wherein the at least one margin signal comprises one of a positive value or a negative value.

[0084] The method of any preceding clause, wherein the nonlinear operation comprises at least one of overmodulation or current limiting.

[0085] The method of any preceding clause, wherein the one or more equipment limits are associated with at least one of power limits, current limits, voltage limits, or energy limits.

[0086] The method of any preceding clause, wherein the allowable grid induced power deviations comprise at least one of inertial power deviations or phase-jump609026-WO-1 / GECW-1237-PCT power deviations occurring because of grid frequency drifts or grid phase angle jumps.

[0087] A system for providing grid-forming control of an inverter-based resource, the system comprising: an inertial power regulator; at least one processor configured to perform a plurality of operations, the plurality of operations comprising: calculating at least one expected operating point based on a power command signal or an indication of grid frequency; dynamically determining at least one margin signal for the inertial power regulator; calculating one or more controller limits for the inertial power regulator based on the at least one expected operating point and the at least one margin signal, wherein the at least one margin signal is reduced when the inverter- based resource experiences nonlinear operation, one or more equipment limits of the inverter-based resource are approached or exceeded, or allowable grid induced power deviations are approached or exceeded; and operating the inertial power regulator of the inverter-based resource based on the one or more controller limits, wherein by reducing the at least one margin signal when the inverter-based resource experiences the nonlinear operation, the one or more equipment limits of the inverter-based resource are approached or exceeded, or the allowable grid induced power deviations are approached or exceeded, the one or more controller limits is constrained within an expected operating range of the inertial power regulator to avoid at least one of regulator windup, equipment overload, or excessive grid-induced power deviations.

[0088] The system of any preceding clause, wherein the plurality of operations further comprise: receiving at least one of the power command signal or the indication of the grid frequency from an external controller.

[0089] The system of any preceding clause, wherein the expected operating point comprises at least one of an angle, frequency, current, or voltage.

[0090] The system of any preceding clause, wherein the one or more controller limits comprises at least one of a frequency minimum limit, a frequency maximum limit, an angle minimum limit, or an angle maximum limit.

[0091] The system of any preceding clause, wherein dynamically determining the at least one margin signal for the inverter-based resource further comprises: dynamically determining a first margin signal around a frequency of a phase-locked loop (PLL) integrator of the inverter-based resource.609026-WO-1 / GECW-1237-PCT

[0092] The system of any preceding clause, wherein dynamically determining the first margin signal around the frequency of the PLL integrator of the inverter-based resource further comprises: receiving an indication of the inverter-based resource experiencing the nonlinear operation or the one or more equipment limits of the inverter-based resource being approached or exceeded; and in response to the indication, applying a scale factor to the first margin signal around the frequency of the PLL integrator of the inverter-based resource to reduce the first margin signal.

[0093] The system of any preceding clause, wherein dynamically determining the at least one margin signal for the inverter-based resource further comprises: dynamically determining a second margin signal around a feedforward angle command and absolute angle limits associated with active power command limits of the inverter-based resource.

[0094] The system of any preceding clause, wherein, during normal operation, the second margin signal is maintained above a certain threshold to provide grid support and to avoid reaching regulator limits when not near the one or more equipment limits, and wherein, when the inverter-based resource experiences the nonlinear operation or the one or more equipment limits of the inverter-based resource are approached or exceeded, the second margin signal is reduced to gradually reduce an amount an angle of the inertial power regulator deviates from the expected operating point.

[0095] 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 structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

609026-WO-1 / GECW-1237-PCT WHAT IS CLAIMED IS:

1. A method for providing grid forming control of an inverter-based resource, the method comprising: calculating at least one expected operating point based on a power command signal or an indication of grid frequency; dynamically determining at least one margin signal for an inertial power regulator of the inverter-based resource; calculating one or more controller limits for the inertial power regulator based on the at least one expected operating point and the at least one margin signal, wherein the at least one margin signal is reduced when the inverter-based resource experiences nonlinear operation, one or more equipment limits of the inverter-based resource are approached or exceeded, or allowable grid induced power deviations are approached or exceeded; and operating the inertial power regulator of the inverter-based resource based on the one or more controller limits, wherein by reducing the at least one margin signal when the inverter-based resource experiences the nonlinear operation, the one or more equipment limits of the inverter-based resource are approached or exceeded, or the allowable grid induced power deviations are approached or exceeded, the one or more controller limits is constrained within an expected operating range of the inertial power regulator to avoid at least one of regulator windup, equipment overload, or excessive grid-induced power deviations.

2. The method of claim 1, further comprising receiving at least one of the power command signal or the indication of the grid frequency from an external controller.

3. The method of claim 1, wherein the expected operating point comprises at least one of an angle, frequency, current, or voltage.

4. The method of claim 1, wherein the one or more controller limits comprises at least one of a frequency minimum limit, a frequency maximum limit, an angle minimum limit, or an angle maximum limit.

5. The method of claim 1, wherein dynamically determining the at least one margin signal for the inverter-based resource further comprises:609026-WO-1 / GECW-1237-PCT dynamically determining a first margin signal around a frequency of a phase- locked loop (PLL) integrator of the inverter-based resource.

6. The method of claim 5, wherein dynamically determining the first margin signal around the frequency of the PLL integrator of the inverter-based resource further comprises: receiving an indication of the inverter-based resource experiencing the nonlinear operation or the one or more equipment limits of the inverter-based resource being approached or exceeded; and in response to the indication, applying a scale factor to the first margin signal around the frequency of the PLL integrator of the inverter-based resource to reduce the first margin signal.

7. The method of claim 1, wherein dynamically determining the at least one margin signal for the inverter-based resource further comprises: dynamically determining a second margin signal around a feedforward angle command associated with an active power command of the inverter-based resource.

8. The method of claim 7, wherein, during normal operation, the second margin signal is maintained above a certain threshold to provide grid support and to avoid reaching regulator limits when not near the one or more equipment limits, and wherein, when the inverter-based resource experiences the nonlinear operation or the one or more equipment limits of the inverter-based resource are approached or exceeded, the second margin signal is reduced to gradually reduce an amount an angle of the inertial power regulator deviates from the expected operating point.

9. The method of claim 1, wherein the at least one margin signal comprises one of a positive value or a negative value.

10. The method of claim 1, wherein the nonlinear operation comprises at least one of overmodulation or current limiting.

11. The method of claim 1, wherein the one or more equipment limits are associated with at least one of power limits, current limits, voltage limits, or energy limits.

12. The method of claim 1, wherein the allowable grid induced power deviations comprise at least one of inertial power deviations or phase-jump power deviations occurring because of grid frequency drifts or grid phase angle jumps.609026-WO-1 / GECW-1237-PCT 13. A system for providing grid-forming control of an inverter-based resource, the system comprising: an inertial power regulator; and at least one processor configured to perform a plurality of operations, the plurality of operations comprising: calculating at least one expected operating point based on a power command signal or an indication of grid frequency; dynamically determining at least one margin signal for the inertial power regulator; calculating one or more controller limits for the inertial power regulator based on the at least one expected operating point and the at least one margin signal, wherein the at least one margin signal is reduced when the inverter-based resource experiences nonlinear operation, one or more equipment limits of the inverter-based resource are approached or exceeded, or allowable grid induced power deviations are approached or exceeded; and operating the inertial power regulator of the inverter-based resource based on the one or more controller limits, wherein by reducing the at least one margin signal when the inverter- based resource experiences the nonlinear operation, the one or more equipment limits of the inverter-based resource are approached or exceeded, or the allowable grid induced power deviations are approached or exceeded, the one or more controller limits is constrained within an expected operating range of the inertial power regulator to avoid at least one of regulator windup, equipment overload, or excessive grid-induced power deviations.

14. The system of claim 13, wherein the plurality of operations further comprise: receiving at least one of the power command signal or the indication of the grid frequency from an external controller.

15. The system of claim 13, wherein the expected operating point comprises at least one of an angle, frequency, current, or voltage.

16. The system of claim 13, wherein the one or more controller limits comprises at least one of a frequency minimum limit, a frequency maximum limit, an609026-WO-1 / GECW-1237-PCT angle minimum limit, or an angle maximum limit.

17. The system of claim 13, wherein dynamically determining the at least one margin signal for the inverter-based resource further comprises: dynamically determining a first margin signal around a frequency of a phase- locked loop (PLL) integrator of the inverter-based resource.

18. The system of claim 17, wherein dynamically determining the first margin signal around the frequency of the PLL integrator of the inverter-based resource further comprises: receiving an indication of the inverter-based resource experiencing the nonlinear operation or the one or more equipment limits of the inverter-based resource being approached or exceeded; and in response to the indication, applying a scale factor to the first margin signal around the frequency of the PLL integrator of the inverter-based resource to reduce the first margin signal.

19. The system of claim 13, wherein dynamically determining the at least one margin signal for the inverter-based resource further comprises: dynamically determining a second margin signal around a feedforward angle command and absolute angle limits associated with active power command limits of the inverter-based resource.

20. The system of claim 19, wherein, during normal operation, the second margin signal is maintained above a certain threshold to provide grid support and to avoid reaching regulator limits when not near the one or more equipment limits, and wherein, when the inverter-based resource experiences the nonlinear operation or the one or more equipment limits of the inverter-based resource are approached or exceeded, the second margin signal is reduced to gradually reduce an amount an angle of the inertial power regulator deviates from the expected operating point.

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