Abstract: The present application relates to a method for controlling a power system connected to a power grid, including: receiving a reactive power instruction and a measured reactive power from a generator; generating a reactive power error signal based on the difference between the reactive power instruction and the measured reactive power; receiving the reactive power error signal; generating a voltage instruction based on reactive power error signal; generating a voltage droop signal based on a reference reactance and a voltage at a point of common coupling; generating a voltage error signal according to at least one of the voltage instruction or the measured terminal voltage of the generator and the voltage droop signal; and producing a reactive current instruction for the converter power path based on the voltage error signal. The present application also discloses a control system for a power system connected to a power grid and a wind farm.

Abstract: The present application relates to a method for controlling a power system connected to a power grid, including: receiving a reactive power instruction and a measured reactive power from a generator; generating a reactive power error signal based on the difference between the reactive power instruction and the measured reactive power; receiving the reactive power error signal; generating a voltage instruction based on reactive power error signal; generating a voltage droop signal based on a reference reactance and a voltage at a point of common coupling; generating a voltage error signal according to at least one of the voltage instruction or the measured terminal voltage of the generator and the voltage droop signal; and producing a reactive current instruction for the converter power path based on the voltage error signal. The present application also discloses a control system for a power system connected to a power grid and a wind farm.

Abstract: A hybrid power generation system is presented. The hybrid power generation system includes a generator operable via a prime mover and configured to generate an alternating current (AC) power. The hybrid power generation system further includes a first power converter electrically coupled to the generator, where the first power converter includes a direct current (DC) link. Furthermore, the hybrid power generation system includes a DC power source configured to be coupled to the DC-link. Moreover, the hybrid power generation system also includes a second power converter. Additionally, the hybrid power generation system includes an integration control sub-system operatively coupled to the first power converter and the DC power source. The integration control sub-system includes at least one bypass switch disposed between the DC power source and the DC-link and configured to connect the DC power source to the DC-link via the second power converter or bypass the second power converter.

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 hybrid power generation system is presented. The hybrid power generation system includes a generator operable via a prime mover and configured to generate an alternating current (AC) power. The hybrid power generation system further includes a first power converter electrically coupled to the generator, where the first power converter includes a direct current (DC) link. Furthermore, the hybrid power generation system includes a DC power source configured to be coupled to the DC-link. Moreover, the hybrid power generation system also includes a second power converter. Additionally, the hybrid power generation system includes an integration control sub-system operatively coupled to the first power converter and the DC power source. The integration control sub-system includes at least one bypass switch disposed between the DC power source and the DC-link and configured to connect the DC power source to the DC-link via the second power converter or bypass the second power converter.

Abstract: A power generation system is disclosed. The power generation system includes an engine coupled to a DFIG and a PV power source to supply a solar electrical power to the DFIG (108). The power generation system also includes a controller configured to operate the engine at a first operating speed corresponding to a first determined efficiency of the engine for a first desired level of an engine power in a first operating condition; or operate the engine at a second operating speed corresponding to a desired level of the second electrical power to be absorbed by a rotor winding and a second desired level of the engine power in a second operating condition, wherein the determined first efficiency is substantially close to a first maximum achievable efficiency of the engine. Method of operating the power generation system is also disclosed.

Abstract: An electrical power system connected to a power grid can include a generator having a stator and a rotor and a power converter. The stator is connected to the power grid via a stator power path. The power converter can include a line-side converter coupled to the power grid via a converter power path and a rotor-side converter coupled to a rotor bus of the rotor and the line-side converter via a DC link. The rotor-side converter is configured to convert a DC power on the DC link to an AC signal for the rotor bus. The power system can also include an active filter having one or more active controlled components. The active filter is coupled in parallel with the rotor-side converter to reduce harmonics of the electrical power system.

Abstract: A control method for increasing reactive power generation of a wind turbine having a Doubly-Fed Induction Generator (DFIG) includes obtaining, by a control device having one or more processors and one or more memory devices, wind forecast data of the wind turbine. Further, the method includes generating, by the control device, a real-time thermal model of the DFIG of the wind turbine using the wind forecast data. More specifically, the thermal model defines a thermal capacity for the DFIG that does not exceed system limits. Thus, the method also includes dynamically adjusting, by the control device, a reactive power set point of the DFIG of the wind turbine based on the real-time thermal model.

Abstract: A hybrid power generation system is presented. The system includes a first power generation subsystem including a prime mover driving a generator including a rotor and a stator, one or more first conversion units coupled to at least one of the rotor and the stator, a first direct current (DC) link, and one or more second conversion units coupled to a corresponding one or more first conversion units via the first DC link. The system includes one or more second power generation subsystems coupled to the first power generation subsystem and one or more power conversion subunits including one or more first bridge circuits coupled to a corresponding one or more second bridge circuits via one or more transformers, where at least one of the one or more second power generation subsystems and the first power generation subsystem includes the one or more power conversion subunits.

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: The present application relates to a method for controlling a power system connected to a power grid, including: receiving a reactive power instruction and a measured reactive power from a generator; generating a reactive power error signal based on the difference between the reactive power instruction and the measured reactive power; receiving the reactive power error signal; generating a voltage instruction based on reactive power error signal; generating a voltage droop signal based on a reference reactance and a voltage at a point of common coupling; generating a voltage error signal according to at least one of the voltage instruction or the measured terminal voltage of the generator and the voltage droop signal; and producing a reactive current instruction for the converter power path based on the voltage error signal. The present application also discloses a control system for a power system connected to a power grid and a wind farm.

Abstract: Systems and methods for operating a power system having a doubly fed induction generator are provided. In example implementations, an electrical power system connected to a power grid can include a generator comprising a stator and a rotor, the stator connected to the power grid via a stator power path, and a power converter. The power converter can include a line-side converter coupled to the power grid via a converter power path and a rotor-side converter coupled to a rotor bus of the rotor and the line-side converter via a DC link, the rotor-side converter configured to convert a DC power on the DC link to an AC signal for the rotor bus. The power system can also include an active filter comprising one or more active controlled components, the active filter being coupled in parallel with the rotor-side converter to reduce harmonics of the electrical power system.

Abstract: A control method for increasing reactive power generation of a wind turbine having a Doubly-Fed Induction Generator (DFIG) includes obtaining, by a control device having one or more processors and one or more memory devices, wind forecast data of the wind turbine. Further, the method includes generating, by the control device, a real-time thermal model of the DFIG of the wind turbine using the wind forecast data. More specifically, the thermal model defines a thermal capacity for the DFIG that does not exceed system limits. Thus, the method also includes dynamically adjusting, by the control device, a reactive power set point of the DFIG of the wind turbine based on the real-time thermal model.

Abstract: A power generation system (101) is disclosed. The power generation system (101) includes a variable speed engine (106) and a DFIG (108) coupled thereto. The DFIG (108) includes a generator (112), a rotor side converter (114), and a line side converter (116) electrically coupled to the generator (112). The rotor side converter (114) is configured to aid in operating the generator (112) as motor to crank the variable speed engine (106). The power generation system (101) further includes a PV power source (110) and/or an energy storage device (122) electrically coupled to a DC-link (118) between the rotor side converter (114) and the line side converter (116). A method of cranking the variable speed engine is also disclosed.

Abstract: A hybrid power generation system is presented. The system includes a first power generation subsystem including a prime mover driving a generator including a rotor and a stator, one or more first conversion units coupled to at least one of the rotor and the stator, a first direct current (DC) link, and one or more second conversion units coupled to a corresponding one or more first conversion units via the first DC link. The system includes one or more second power generation subsystems coupled to the first power generation subsystem and one or more power conversion subunits including one or more first bridge circuits coupled to a corresponding one or more second bridge circuits via one or more transformers, where at least one of the one or more second power generation subsystems and the first power generation subsystem includes the one or more power conversion subunits.

Abstract: An uninterruptable power supply (UPS) system for providing power to a load coupled to a utility power source is provided. The UPS system includes a doubly-fed induction generator (DFIG), a rechargeable energy storage system, a first inverter, and a controller in communication with the DFIG and the first inverter. The DFIG includes a stator and a rotor coupled to the load. The stator and rotor are magnetically coupled together. The DFIG generates an auxiliary power output. The first inverter is coupled between the rotor and the rechargeable energy storage system. The controller detects a power disturbance associated with the utility power source and controls the first inverter to provide an excitation input to the rotor in response to the power disturbance. The DFIG provides the auxiliary power output to the load based on the excitation input.

Abstract: An uninterruptible power supply (UPS) includes a line terminal, a load terminal, a double-conversion circuit coupled in series, and further includes a bypass circuit, and a synchronize circuit. The line terminal couples to a doubly fed induction generator (DFIG). The load terminal couples to a load having a demanded power. The double-conversion circuit regulates grid power from the line terminal to the demanded power at the load terminal. The bypass circuit is coupled between the line terminal and the load terminal, and configured to deliver regulated power generated by the DFIG to the load terminal when the grid power is lost. The synchronize circuit is coupled between the double-conversion circuit and the DFIG, and, when the grid power is lost, the synchronize circuit injects a current through the double-conversion circuit and into the DFIG, synchronizing the regulated power generated by the DFIG to the demanded power.

Abstract: A hybrid AC and DC distribution system includes a doubly fed induction generator (DFIG), a DC distribution bus, an AC/DC converter, an AC distribution bus, and a DC/AC converter. The DFIG includes a rotor and a stator, and is configured to generate a first AC power at the rotor and a second AC power at the stator. The AC/DC converter is coupled to the rotor and the DC distribution bus. The AC/DC converter converts the first AC power to a first DC power at a first node for delivery to a first load through the DC distribution bus. The DC/AC converter is coupled between the first node and a second node coupled to the stator and the AC distribution bus. The DC/AC converter converts the first DC power to the second AC power at the second node for delivery to a second load through the AC distribution bus.

Abstract: An uninterruptable power supply (UPS) system for providing power to a load coupled to a utility power source is provided. The UPS system includes a doubly-fed induction generator (DFIG), a rechargeable energy storage system, a first inverter, and a controller in communication with the DFIG and the first inverter. The DFIG includes a stator and a rotor coupled to the load. The stator and rotor are magnetically coupled together. The DFIG generates an auxiliary power output. The first inverter is coupled between the rotor and the rechargeable energy storage system. The controller detects a power disturbance associated with the utility power source and controls the first inverter to provide an excitation input to the rotor in response to the power disturbance. The DFIG provides the auxiliary power output to the load based on the excitation input.

Abstract: A direct current power (DC) distribution system includes a plurality of DC power sources, a ring bus, a plurality of switch assemblies, and a plurality of passive protection assemblies. Each DC power source is coupled to the ring bus by a respective switch assembly and a respective passive protection assembly.