Abstract: A method for providing grid-forming control of a double-fed generator of a wind turbine includes receiving, via a stator voltage regulator of a converter controller, one or more voltage commands from an external controller. Further, the method includes determining, via the stator voltage regulator, one or more rotor current commands as a function of a magnetizing current command and a stator current feedback signal of the double-fed generator. Thus, the method includes controlling a rotor voltage of the double-fed generator using the one or more rotor current commands to achieve the one or more voltage commands.

Abstract: A method for controlling an inverter-based resource (IBR) having a power converter connected to an electrical grid includes receiving a first power limit signal for the IBR from an external controller, receiving a second power limit signal for the IBR, and determining a constrained power limit signal based on the first and second power limit signals. The method also includes applying a first frequency droop function to the constrained power limit signal and determining at least one of a power reference signal or a pitch reference signal for the IBR as a function of an output of the first frequency droop function and the constrained power limit signal. Further, the method includes determining one or more control commands for the IBR based on at least one of the power reference signal or the pitch reference signal and controlling the IBR based on the control command(s) so as to support a grid frequency of the electrical grid within power available at the IBR.

Abstract: A method for controlling an inverter-based resource (IBR) connected to an electrical grid includes receiving grid parameter(s) and applying a droop function to the grid parameter(s) to determine a power droop signal. Further, the method includes receiving a power reference signal. Moreover, the method includes determining a power command signal as a function of the power droop signal and the power reference signal to allow for a fast response in a power output of the IBR to the grid parameter(s). The method also includes applying power constraint(s) to the power command signal to limit how much the power output of the IBR can be changed due to the grid parameter(s). Further, the method includes determining one or more control commands for the IBR based, at least in part, on the power command signal. Thus, the method includes controlling the IBR based, at least in part, on the power command signal.

Abstract: A method for providing grid-forming control of a double-fed wind turbine generator connected to an electrical grid includes receiving at least one control signal associated with a desired total power output or a total current output of the double-fed wind turbine generator. The method also includes determining a contribution of at least one of power or current from the line-side converter to the desired total power output or to the total current output of the double-fed wind turbine generator, respectively. The method also includes determining a control command for a stator of the double-fed wind turbine generator based on the contribution of at least one of the power or the current from the line-side converter and the at least one control signal. Further, the method includes using the control command to regulate at least one of power or current in the stator of the double-fed wind-turbine generator.

Abstract: A method for controlling a power system includes generating, via at least one inverter-based resource, one or more command signals via a regulator of at least one inverter-based resource of the power system. Further, the method includes dynamically estimating, via the at least one inverter-based resource, a reactive power capability of the at least one inverter-based resource based, at least in part, on the one or more command signals. Further, the method includes sending, via the at least one inverter-based resource, the reactive power capability to the system-level controller. Thus, the method includes controlling the power system based on the reactive power capability.

Abstract: A method for controlling a wind turbine power system connected to an electrical grid includes determining, via a controller, at least one non-linear magnetizing parameter of a double-fed wind turbine generator of the wind turbine power system. The method also includes developing, via the controller, a model of the non-linear magnetizing parameter(s) of the double-fed wind turbine generator. Further, the method includes using, via the controller, the model in a stator voltage regulator of the double-fed wind turbine generator to provide grid-forming control of the double-fed wind turbine generator.

Abstract: A method for controlling a wind turbine power system connected to an electrical grid includes determining, via a controller, at least one non-linear magnetizing parameter of a double-fed wind turbine generator of the wind turbine power system. The method also includes developing, via the controller, a model of the non-linear magnetizing parameter(s) of the double-fed wind turbine generator. Further, the method includes using, via the controller, the model in a stator voltage regulator of the double-fed wind turbine generator to provide grid-forming control of the double-fed wind turbine generator.

Abstract: A method for providing grid-forming control of an inverter-based resource includes receiving a negative-sequence voltage feedback of the inverter-based resource. The method also includes receiving at least one negative-sequence feedback signal of the inverter-based resource. The method also includes determining, via a negative-sequence regulator, one or more control signals indicative of a desired negative-sequence impedance of the inverter-based resource using the at least one negative-sequence feedback signal. Further, the method includes generating, via the negative-sequence regulator, a control command for the inverter-based resource based on the one or more control signals. Moreover, the method includes controlling the inverter-based resource based on the control command to achieve the desired negative-sequence impedance of the inverter-based resource.

Abstract: A method for providing grid-forming control of a double-fed wind turbine generator connected to an electrical grid includes receiving at least one control signal associated with a desired total power output or a total current output of the double-fed wind turbine generator. The method also includes determining a contribution of at least one of power or current from the line-side converter to the desired total power output or to the total current output of the double-fed wind turbine generator, respectively. The method also includes determining a control command for a stator of the double-fed wind turbine generator based on the contribution of at least one of the power or the current from the line-side converter and the at least one control signal. Further, the method includes using the control command to regulate at least one of power or current in the stator of the double-fed wind-turbine generator.

Abstract: A method for providing grid-forming control of an inverter-based resource includes receiving, via a controller, one or more reference commands from an external controller. The method also includes determining, via the controller, one or more control commands for the inverter-based resource based on the one or more reference commands. Further, the method includes determining, via the controller, at least one feedforward signal as a function of the one or more control commands, one or more control signals, and one or more estimated electrical conditions of the inverter-based resource. The method also includes using the feedforward signal(s) to position at least one control angle of the inverter-based resource to an anticipated value needed to achieve the one or more reference commands, thereby enabling rapid response to the one or more reference commands received from the external controller.

Abstract: A method for providing grid-forming control of an inverter-based resource connected to an electrical grid includes providing, via a processor, at least one virtual impedance value of the inverter-based resource. The method also includes determining a voltage drop across the at least one virtual impedance value of the inverter-based resource using at least one current feedback signal, the voltage drop comprising a voltage magnitude and a voltage angle. Further, the method includes receiving one or more voltage or current signals of the inverter-based resource. Moreover, the method includes determining a control command for the inverter-based resource as a function of the voltage drop across the virtual impedance value(s) of the inverter-based resource and the one or more voltage or current signals.

Abstract: A method for operating a inverter-based resource connected to a power grid includes receiving one or more voltage feedback signals created by at least one component of the inverter-based resource, wherein distortion components of the one or more voltage feedback signals are more sensitive to voltage distortion created by the inverter-based resource than by external sources of voltage distortion. Further, the method includes extracting a distortion component of the one or more feedback signals having a certain phase sequence and frequency. Moreover, the method includes determining a voltage command for the power converter as a function of, at least, the distortion component. Thus, the method includes controlling the power converter based on the voltage command such that the voltage distortion created by the at least one component of the inverter-based resource is reduced in a manner that is relatively insensitive to voltage distortion created by sources external to the inverter-based resource.

Abstract: A method for controlling a power system includes generating, via at least one inverter-based resource, one or more command signals via a regulator of at least one inverter-based resource of the power system. Further, the method includes dynamically estimating, via the at least one inverter-based resource, a reactive power capability of the at least one inverter-based resource based, at least in part, on the one or more command signals. Further, the method includes sending, via the at least one inverter-based resource, the reactive power capability to the system-level controller. Thus, the method includes controlling the power system based on the reactive power capability.

Abstract: A method for operating a inverter-based resource connected to a power grid includes receiving one or more voltage feedback signals created by at least one component of the inverter-based resource, wherein distortion components of the one or more voltage feedback signals are more sensitive to voltage distortion created by the inverter-based resource than by external sources of voltage distortion. Further, the method includes extracting a distortion component of the one or more feedback signals having a certain phase sequence and frequency. Moreover, the method includes determining a voltage command for the power converter as a function of, at least, the distortion component. Thus, the method includes controlling the power converter based on the voltage command such that the voltage distortion created by the at least one component of the inverter-based resource is reduced in a manner that is relatively insensitive to voltage distortion created by sources external to the inverter-based resource.

Abstract: A system and method for mitigating overvoltage on a DC link of a power converter of an electrical power system connected to a power grid includes receiving a voltage feedback signal from the DC link for a predetermined time period. The method also includes determining a rate of change of the voltage feedback signal during the predetermined time period. Further, the method includes predicting a future voltage value on the DC link as a function of the voltage feedback signal and the rate of change of the voltage feedback signal. Moreover, the method includes controlling the electrical power system based on the future voltage value.

Abstract: In an aspect, a method for detecting the presence or absence of tumor in a polynucleotide sample obtained from a subject comprising: (i) adding carrier nucleic acid molecules to the polynucleotide sample to generate a first sample; wherein the set of carrier nucleic acid molecules comprises at least one subset of unmethylated carrier nucleic acid molecules and/or at least one subset of methylated carrier nucleic acid molecules and at least one end of the carrier nucleic acid molecules is modified to prevent ligation; (ii) partitioning the first sample into at least two partitioned sets using capturing agent that binds selectively to methylated polynucleotides; (iii) processing the partitioned sample to generate processed sample, wherein the processing comprises: tagging, amplifying and enriching; (iv) sequencing the processed sample to generate a set of sequencing reads; and (v) analyzing a plurality of sequencing reads to detect the presence or absence of tumor.

Abstract: A method for operating an inverter-based resource includes monitoring a current magnitude in the inverter-based resource. The method also includes monitoring a voltage magnitude in the inverter-based resource. Further, the method includes comparing the current magnitude in the inverter-based resource to a primary current threshold. Moreover, the method includes comparing the voltage magnitude in the inverter-based resource to a voltage threshold. As such, the method also includes disabling switching of the switching elements of the power converter when the current magnitude increases above the primary current threshold and the voltage magnitude decreases below the voltage threshold to bypass the switching elements of the power converter until excess energy in the inverter-based resource is dissipated.

Abstract: A method for controlling a dual-fed induction generator (DFIG) connected to a power grid in response to a high-voltage grid event includes receiving, via a controller, a frequency signal of the power grid. The method also includes filtering the frequency signal via a filtering assembly so as to determine whether certain types of grid conditions are present in the power grid. The filtering assembly includes a first filter connected in parallel with a second filter. The first filter has a bandwidth that is greater than the second filter. Further, the method also includes comparing output signals of the first and second filters of the filtering assembly to one or more frequency thresholds. Moreover, the method includes controlling the DFIG based on the comparison.

Abstract: A method for controlling a dual-fed induction generator (DFIG) connected to a power grid in response to a high-voltage grid event includes receiving, via a controller, a frequency signal of the power grid. The method also includes filtering the frequency signal via a filtering assembly so as to determine whether certain types of grid conditions are present in the power grid. The filtering assembly includes a first filter connected in parallel with a second filter. The first filter has a bandwidth that is greater than the second filter. Further, the method also includes comparing output signals of the first and second filters of the filtering assembly to one or more frequency thresholds. Moreover, the method includes controlling the DFIG based on the comparison.

Abstract: A method for controlling voltage of a DC link of a power converter of an electrical power system connected to a power grid includes operating the DC link to an optimum voltage set point that achieves steady state operation of the power converter. The method also includes monitoring the power grid for one or more transient events that may be an indicator of one or more sub-synchronous control interaction (SSCI) conditions occurring in the electrical power system. Upon detection of the transient event(s) occurring in the power grid, the method also includes immediately increasing the optimum voltage set point to a higher voltage set point of the DC link. Moreover, the method includes operating the DC link at the higher voltage set point until the sub-synchronous control interaction(s) is damped, thereby optimizing voltage control of the DC link.