Abstract: A method for controlling an electrical power system connected to a power grid includes receiving a reactive power command and a measured reactive power and generating a reactive power error signal based on a difference between the reactive power command and the measured reactive power. Further, the method includes receiving, via a reactive power regulator, the reactive power error signal. Moreover, the method includes generating, via the reactive power regulator, a voltage command based on the error signal. The method also includes generating, via a droop control, a voltage droop signal. In addition, the method includes generating a voltage error signal as a function of the voltage droop signal and at least one of the voltage command or a measured terminal voltage. Thus, the method further includes generating, via a voltage regulator, a reactive current command based on the voltage error signal.

Abstract: A power generation system (100, 200, 300, 400) is presented. The power generation system includes a prime mover (102), a doubly-fed induction generator (DFIG) (104) having a rotor winding (126) and a stator winding (122), a rotor-side converter (106), a line-side converter (108), and a secondary power source (110, 401) electrically coupled to a DC-link (128). Additionally, the power generation system includes a control sub-system (112, 212, 312) having a controller, and a plurality of switching elements (130, and 132 or 201). The controller is configured to selectively control switching of one or more switching elements (130, and 132 or 201) based on a value of an operating parameter corresponding to at least one of the prime mover, the DFIG, or the secondary power source to connect the rotor-side converter in parallel to the line-side converter to increase an electrical power production by the power generation system.

Abstract: A method for reactive power control of a wind farm having a plurality of clusters of wind turbines with a cluster transformer connecting each cluster of wind turbines to a power grid is provided. The method includes receiving, via a plurality of cluster-level controllers, a reactive power command from a farm-level controller. The method also includes generating, via the cluster-level controllers, a cluster-level reactive current command for each cluster of wind turbines based on the reactive power command. Further, the method includes distributing, via the cluster-level controllers, a turbine-level reactive current command to turbine-level controllers of the wind turbines based on the cluster-level reactive current command.

Abstract: A method for operating an electrical power system includes detecting a bridge current magnitude in a rotor-side converter or line-side converter of a power converter, the power converter electrically coupled between a generator rotor and a transformer. The method further includes comparing the bridge current magnitude in the one of the rotor-side converter or line-side converter to a primary predetermined threshold. The method further includes disabling bridge switching of one of the rotor-side converter or line-side converter when the bridge current magnitude exceeds the primary predetermined threshold.

Abstract: An electrical power subsystem includes a generator comprising a generator stator and a generator rotor, and a power converter electrically coupled to the generator. The power converter includes a plurality of rotor-side converters electrically coupled in parallel, a line-side converter, and a regulated DC link electrically coupling the plurality of rotor-side converters and the line-side converter. The electrical power subsystem further includes a stator power path for providing power from the generator stator to the power grid, and a converter power path for providing power from the generator rotor through the power converter to the power grid.

Abstract: An electrical power system includes a cluster of electrical power subsystems, each of the electrical power subsystems including a power converter electrically coupled to a generator having a generator rotor and a generator stator. Each of the electrical power subsystems defines a stator power path and a converter power path for providing power to the power grid. The converter power path includes a partial power transformer. The electrical power system further includes a subsystem breaker configured with each of the electrical power subsystems, and a cluster transformer for connecting each cluster of electrical power subsystems to the power grid. The electrical power system further includes a cluster power path extending between each subsystem breaker and the cluster transformer, and a distortion filter electrically coupled to the cluster transformer. The distortion filter reduces harmonics in current flowing from the electrical power subsystems to the cluster transformer.

Abstract: A method for controlling an electrical power system connected to a power grid includes receiving a reactive power command and a measured reactive power and generating a reactive power error signal based on a difference between the reactive power command and the measured reactive power. Further, the method includes receiving, via a reactive power regulator, the reactive power error signal. Moreover, the method includes generating, via the reactive power regulator, a voltage command based on the error signal. The method also includes generating, via a droop control, a voltage droop signal. In addition, the method includes generating a voltage error signal as a function of the voltage droop signal and at least one of the voltage command or a measured terminal voltage. Thus, the method further includes generating, via a voltage regulator, a reactive current command based on the voltage error signal.

Abstract: A method for reactive power control of a wind farm having a plurality of clusters of wind turbines with a cluster transformer connecting each cluster of wind turbines to a power grid is provided. The method includes receiving, via a plurality of cluster-level controllers, a reactive power command from a farm-level controller. The method also includes generating, via the cluster-level controllers, a cluster-level reactive current command for each cluster of wind turbines based on the reactive power command. Further, the method includes distributing, via the cluster-level controllers, a turbine-level reactive current command to turbine-level controllers of the wind turbines based on the cluster-level reactive current command.

Abstract: A power generation system (100, 200, 300, 400) is presented. The power generation system includes a prime mover (102), a doubly-fed induction generator (DFIG) (104) having a rotor winding (126) and a stator winding (122), a rotor-side converter (106), a line-side converter (108), and a secondary power source (110, 401) electrically coupled to a DC-link (128). Additionally, the power generation system includes a control sub-system (112, 212, 312) having a controller, and a plurality of switching elements (130, and 132 or 201). The controller is configured to selectively control switching of one or more switching elements (130, and 132 or 201) based on a value of an operating parameter corresponding to at least one of the prime mover, the DFIG, or the secondary power source to connect the rotor-side converter in parallel to the line-side converter to increase an electrical power production by the power generation system.

Abstract: A method for controlling an electrical power subsystem includes determining an auxiliary voltage error value based on a measured voltage of the low voltage distribution panel. The method further includes receiving an active current command. The method further includes calculating a switching pattern for a line-side converter of the power converter based on the auxiliary voltage error value and the active current command. A current level produced by the line-side converter controls a voltage to the low voltage distribution panel.

Abstract: The present disclosure is directed to a method for protecting an electrical power system connected to a power grid. The electrical power system includes at least one cluster of electrical power subsystems. Each of the electrical power subsystems defines a stator power path and a converter power path for providing power to the power grid. The converter power path includes a partial power transformer. The electrical power system further includes a subsystem switch configured with each of the electrical power subsystems and a cluster transformer connecting each cluster of electrical power subsystems to the power grid. A cluster switch is configured with the cluster transformer. A controller is communicatively coupled to each of the plurality of electrical power subsystems. Thus, the controller monitors the electrical power system for faults, and if a fault is detected in the cluster, sends, via one of the subsystem switches or the power converters, a block signal to the cluster switch.

Abstract: A wind generation system includes a wind turbine for generating mechanical power, a doubly-fed induction generator for converting the mechanical power to electrical power, a converter for converting the electrical power to a desired electrical power for supplying to a power grid, and a transformer through which a stator of the generator is coupled to the power grid. When a measured rotation speed feedback from the rotor of the generator is lower than an original cut-in rotation speed of the rotor, a cut-in rotation speed of the rotor is lowered by determining a DC link voltage margin of the converter, determining a DC link voltage setpoint of the converter based on the determined DC link voltage margin; and controlling the converter based on the determined DC link voltage setpoint; and/or by increasing a turn ratio of the transformer to reduce a grid voltage from the power grid.

Abstract: The present subject matter is directed to an electrical power circuit connected to a power grid and method of operating same. The electrical power circuit has a power converter electrically coupled to a generator, such as a doubly-fed induction generator, having a rotor and a stator. Thus, the method includes operating rotor connections of the rotor of the generator in a wye configuration during a first rotor speed operating range. Further, the method includes monitoring a rotor speed of the rotor of the generator. Thus, the method also includes transitioning the rotor connections of the rotor from the wye configuration to a delta configuration if the rotor speed changes to a second rotor speed operating range.

Abstract: A method for controlling an electrical power subsystem includes determining an auxiliary voltage error value based on a measured voltage of the low voltage distribution panel. The method further includes receiving an active current command. The method further includes calculating a switching pattern for a line-side converter of the power converter based on the auxiliary voltage error value and the active current command. A current level produced by the line-side converter controls a voltage to the low voltage distribution panel.

Abstract: A method for operating an electrical power system includes detecting a bridge current magnitude in a rotor-side converter or line-side converter of a power converter, the power converter electrically coupled between a generator rotor and a transformer. The method further includes comparing the bridge current magnitude in the one of the rotor-side converter or line-side converter to a primary predetermined threshold. The method further includes disabling bridge switching of one of the rotor-side converter or line-side converter when the bridge current magnitude exceeds the primary predetermined threshold.

Abstract: An electrical power system includes a cluster of electrical power subsystems, each of the electrical power subsystems including a power converter electrically coupled to a generator having a generator rotor and a generator stator. Each of the electrical power subsystems defines a stator power path and a converter power path for providing power to the power grid. The converter power path includes a partial power transformer. The electrical power system further includes a subsystem breaker configured with each of the electrical power subsystems, and a cluster transformer for connecting each cluster of electrical power subsystems to the power grid. The electrical power system further includes a cluster power path extending between each subsystem breaker and the cluster transformer, and a distortion filter electrically coupled to the cluster transformer. The distortion filter reduces harmonics in current flowing from the electrical power subsystems to the cluster transformer.

Abstract: An electrical power subsystem includes a generator comprising a generator stator and a generator rotor, and a power converter electrically coupled to the generator. The power converter includes a plurality of rotor-side converters electrically coupled in parallel, a line-side converter, and a regulated DC link electrically coupling the plurality of rotor-side converters and the line-side converter. The electrical power subsystem further includes a stator power path for providing power from the generator stator to the power grid, and a converter power path for providing power from the generator rotor through the power converter to the power grid.

Abstract: The present disclosure is directed to a method for protecting an electrical power system connected to a power grid. The electrical power system includes at least one cluster of electrical power subsystems. Each of the electrical power subsystems defines a stator power path and a converter power path for providing power to the power grid. The converter power path includes a partial power transformer. The electrical power system further includes a subsystem switch configured with each of the electrical power subsystems and a cluster transformer connecting each cluster of electrical power subsystems to the power grid. A cluster switch is configured with the cluster transformer. A controller is communicatively coupled to each of the plurality of electrical power subsystems. Thus, the controller monitors the electrical power system for faults, and if a fault is detected in the cluster, sends, via one of the subsystem switches or the power converters, a block signal to the cluster switch.

Abstract: The present subject matter is directed to a system and method for operating an electrical power circuit connected to a power grid. The electrical power circuit has a power converter electrically coupled to a generator. The method includes monitoring a rotor speed of the generator during operation of the electrical power circuit. The method also includes increasing an operating range of the rotor speed of the generator. Further, the method includes determining at least one of a line-side voltage of a line-side converter of the power converter or a rotor-side voltage of a rotor-side converter of the power converter during operation of the electrical power circuit. Another step include controlling, via a converter controller, a DC link voltage of a DC link of the power converter as a function of one or more of the line-side voltage, the rotor-side voltage, and/or the rotor speed.

Abstract: A wind generation system includes a wind turbine for generating mechanical power, a doubly-fed induction generator for converting the mechanical power to electrical power, a converter for converting the electrical power to a desired electrical power for supplying to a power grid, and a transformer through which a stator of the generator is coupled to the power grid. When a measured rotation speed feedback from the rotor of the generator is lower than an original cut-in rotation speed of the rotor, a cut-in rotation speed of the rotor is lowered by determining a DC link voltage margin of the converter, determining a DC link voltage setpoint of the converter based on the determined DC link voltage margin; and controlling the converter based on the determined DC link voltage setpoint; and/or by increasing a turn ratio of the transformer to reduce a grid voltage from the power grid.