The present application provides a method and a system for controlling continuous high voltage ride-through and low voltage ride-through of a permanent magnet direct-driven wind turbine. The method includes: determining a transient time period during which the wind turbine is transitioned from a high voltage ride-through state to a low voltage ride-through state; controlling the wind turbine to provide, during the transient time period, a gradually increasing active current to the point of common coupling; and controlling the wind turbine to provide, during the transient time period, a reactive current to the point of common coupling according to an operation state of the wind turbine before the high voltage ride-through state.

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.

The present subject matter is directed to a system and method for regulating reactive power in a wind farm connected to a power grid so as to improve reactive speed-of-response of the wind farm. The method includes receiving a voltage feedback from the power grid and a voltage reference and calculating a linear voltage error as a function of the voltage feedback and the voltage reference. A further step includes generating a first output based on the linear voltage error via a first control path having a first voltage regulator. A further step includes determining a non-linear voltage error based on the linear voltage error via a second control path having a second voltage regulator. A second output is generated via the second control path based on the non-linear voltage error. As such, a reactive power command is generated as a function of the first and second outputs.

A method (1000, 1001) for operating a wind turbine (100-100d) is disclosed. The wind turbine includes a rotor (106) with rotor blades (108), a power conversion system (118, 210, 234) mechanically connected with the rotor (106), a first subsystem (310 ), a second subsystem (320), and an internal electric power distribution system (300-301b, 321, 322) connectable with the first subsystem (310) and the second subsystem (320). During operating (1100) the wind turbine (100-100d) in a normal operating mode in which the power conversion system (118, 210, 234) converts input motive power into electrical output power (P), the method (1000) includes detecting (1200) an increased power demand of the first subsystem (310), and actively increasing (1300) an amount (P1) of electric power (Pint) flowing through the internal electric power distribution system (300-301b, 321, 322) to the first subsystem (310) if a power demand of the second subsystem (320) is at least reduced.

A wind turbine converter system with a rectifier and an inverter and a converter controller has at least first and second converter strings. The converter system is controlled by a master-converter controller and a slave-converter controller. The master-converter controller controls the first converter string and the slave-converter controller controls the second converter string. The master-converter controller receives commands from a superordinate wind turbine controller, provides the slave-converter controller with string-control commands on the basis of the superordinate control commands, and controls the conversion operation of the first converter string on the basis of the superordinate control command. The slave-converter controller receives the string-control commands from the master-converter controller and controls the conversion operation of the second converter string on the basis of the string-control commands received. The first and the second converter strings can be arranged in a bipolar configuration giving access to a neutral point. Fault detection can be performed based on current through the neutral. The system is capable of fault ride-through. Also, in case of failure of the master-converter controller, a redundant unit takes its place.

A method for providing grid-forming control of an inverter-based resource includes receiving, via a controller, a power reference signal. The method also includes determining a dynamic power change limit. Further, the method includes determining, via the controller, an upper power boundary and a lower power boundary for grid-induced power deviations from a desired power operating point based on the power reference signal. Moreover, the method includes determining, via the controller, limits for an inertial power regulator reference based, at least in part, on the upper and lower power boundaries and the dynamic power change limit. In addition, the method includes applying, via the controller, the limits to the inertial power regulator reference in an inertial power regulator of the inverter-based resource.

A method for damping sub-synchronous control interactions (SSCI) in a grid-forming inverter-based resource connected to an electrical grid includes receiving, via a controller, a current feedback signal in a synchronous reference frame. The method also includes rotating, via the controller, the current feedback signal to a new reference frame associated with a sub-synchronous frequency range. Further, the method includes determining, via the controller, a sub-synchronous component of the current feedback signal. Moreover, the method includes rotating, via the controller, the sub-synchronous component of the current feedback signal back to the synchronous reference frame. In addition, the method includes determining, via the controller, a voltage command associated with sub-synchronous damping for the inverter-based resource as a function of the sub-synchronous component and a virtual resistance setting. Thus, the method includes controlling, via the controller, the inverter-based resource, based at least in part, on the voltage command associated with the sub-synchronous damping.

A method for operating a wind turbine power system connected to an electrical grid includes collecting data relating to one or more parameters of one or more electrical components of the wind turbine power system. The method may also include performing a statistical analysis of the data relating to one or more parameters of the one or more electrical components. Further, the method includes predicting future behavior of the electrical component(s) based on the statistical analysis. Moreover, the method includes determining set points for the electrical component(s) using the predicted future behavior. In addition, the method includes operating the wind turbine power system at the determined set points for the electrical component(s) so as to optimize at least one characteristic of the electrical component(s).

A method for operating a multi-level bridge power converter of an electrical power system connected to a power grid includes receiving, via a controller of the power converter, an indication of a transient event occurring in the power grid or the electrical power system. The power converter has a plurality of switching devices arranged in an active neutral point clamped topology. Accordingly, upon receiving the indication, the method includes activating a crowbar algorithm programmed in the controller of the power converter to bifurcate a current received by the power converter into a plurality of different current paths defined by the plurality of switching devices.

The present disclosure is directed to a system and method for controlling a wind farm. The method includes operating the wind farm based on multiple control settings over a plurality of time intervals. A next step includes collecting one or more wind parameters of the wind farm over the plurality of time intervals and one or more operating data points for each of the wind turbines in the wind farm for the plurality time intervals. The method also includes calculating a contribution of the operating data points for each of the wind turbines as a function of the one or more wind parameters. Further steps of the method include estimating an energy production for the wind farm for each of the control settings based at least in part on the contribution of the operating data points and controlling the wind farm based on optimal control settings.