Abstract: An output filter for a power conversion system having a plurality of power converters connected in parallel, the output filter including a magnetic core and a plurality of filtering windings each wound around a corresponding one of a plurality of segments of the magnetic core and corresponding to one of the plurality of power converters, each of the plurality of filtering windings including a free-end configured for connection to an output of a corresponding one of the plurality of power converters and a second end, the second ends of all of the filtering windings being electrically connected to each other in a common connection; at least one additional winding wound around the additional segment of the magnetic core, the additional winding having a free-end for being connected to an electrical grid and a second end connected to the common connection.

Abstract: A method which is suitable for a system having a frequency converter and a generator, both of which are connected to a power grid, includes obtaining sub-synchronous components of the grid voltage and determining damping current set points according to the sub-synchronous components to compensate for sub-synchronous resonances of the grid. Damping current set points are determined by receiving the sub-synchronous components of the grid voltage and returning damping current set points as outputs. A variable damping gain is adjusted according to the sub-synchronous frequency of the grid, such that the required compensation level can be adapted to the frequency converter for damping sub-synchronous resonance of the grid.

Abstract: The present invention relates to an electric energy conversion method and system with at least two conversion units (14), comprising control means (12) establishing the maximum output current of the operative conversion modules, as well as the commutation frequency of the entire or of a sub-group of the operative conversion modules to thus increase the availability of the conversion system in the event of failures.

Abstract: An output filter for a power conversion system having a plurality of power converters connected in parallel, the output filter including a magnetic core and a plurality of filtering windings each wound around a corresponding one of a plurality of segments of the magnetic core and corresponding to one of the plurality of power converters, each of the plurality of filtering windings including a free-end configured for connection to an output of a corresponding one of the plurality of power converters and a second end, the second ends of all of the filtering windings being electrically connected to each other in a common connection; at least one additional winding wound around the additional segment of the magnetic core, the additional winding having a free-end for being connected to an electrical grid and a second end connected to the common connection.

Abstract: A kit for a wind station having a fixed speed wind turbine with a generator configured to be coupled to a grid by a coupling device so that the turbine operates at a fixed frequency equal to the frequency of the grid. The kit includes a back-to-back power converter configured for connection between the generator and the grid, and the power converter includes a machine side converter, a grid side converter and a DC link between both converters, a controller for controlling the power converter, and a connection point for receiving at least one parameter of the generator of the turbine. The connection point is communicated with the controller, and the controller is configured to act upon the power controller depending on said parameter.

Abstract: A wind turbine that includes a housing, an asynchronous generator disposed in the housing and configured to be electrically connected to a power grid connection; a power converter circuit disposed in the housing and configured to be electrically connected to the asynchronous generator; and a variable impedance device disposed in the housing, connected to the generator and configured to limit current by varying impedance in response to a transient current. The wind turbine delivers reactive power to the power grid when the variable impedance device varies impedance in response to the transient current. The variable impedance device can be arranged in series between the asynchronous generator and the power grid connection, or can be in a shunt arrangement between the asynchronous generator and a neural point.

Abstract: A method which is suitable for a system having a frequency converter and a generator, both of which are connected to a power grid, includes obtaining sub-synchronous components of the grid voltage and determining damping current set points according to the sub-synchronous components to compensate for sub-synchronous resonances of the grid. Damping current set points are determined by receiving the sub-synchronous components of the grid voltage and returning damping current set points as outputs. A variable damping gain is adjusted according to the sub-synchronous frequency of the grid, such that the required compensation level can be adapted to the frequency converter for damping sub-synchronous resonance of the grid.

Abstract: Kit and method for a wind station comprising a fixed speed wind turbine with a generator being coupled to a grid by means of a coupling device so that the turbine operates at a fixed grid current frequency of the grid. The kit (100) is adapted to be coupled between the generator (10) of the wind turbine (1) and the grid (2), replacing at least the coupling device, the kit (100) turning the fixed speed wind turbine into a variable speed wind turbine.

Abstract: A control method for multi-converter systems wherein all DC/AC converters (1.1-1.n) are connected to a single transformer (2) via a single primary winding. The method of the present invention stands out mainly because it controls the common-mode voltage generated by the different DC/AC converters (1.1-1.n) so that said voltage falls mainly on the transformer (2).

Abstract: A wind turbine that includes a housing, an asynchronous generator disposed in the housing and configured to be electrically connected to a power grid connection; a power converter circuit disposed in the housing and configured to be electrically connected to the asynchronous generator; and a variable impedance device disposed in the housing, connected to the generator and configured to limit current by varying impedance in response to a transient current. The wind turbine delivers reactive power to the power grid when the variable impedance device varies impedance in response to the transient current. The variable impedance device can be arranged in series between the asynchronous generator and the power grid connection, or can be in a shunt arrangement between the asynchronous generator and a neural point.

Abstract: The present invention relates to an electric energy conversion method and system with at least two conversion units (14), comprising control means (12) establishing the maximum output current of the operative conversion modules, as well as the commutation frequency of the entire or of a sub-group of the operative conversion modules to thus increase the availability of the conversion system in the event of failures.

Abstract: A control method for multi-converter systems wherein all DC/AC converters (1.1-1.n) are connected to a single transformer (2) via a single primary winding. The method of the present invention stands out mainly because it controls the common-mode voltage generated by the different DC/AC converters (1.1-1.n) so that said voltage falls mainly on the transformer (2).

Abstract: It allows connecting or disconnecting polyphase conversion stages (2a, 2b), comprising at least two polyphase back-to-back conversion stages (2a, 2b) connected between a rotary electric machine (3) and the power grid (4), each of these stages having two converters and one DC bus (6a, 6b); at least as many switching cells in each phase as there are conversion stages (2a, 2b), wherein at least one of the cells is associated to each of the conversion stages (2a, 2b); cut-off means (7) between the DC buses (6a, 6b) of the at least two polyphase conversion stages (2a, 2b); cut-off means (8a, 8b) between the at least two conversion stages (2a, 2b) and the rotary electric machine; and cut-off means (9a, 9b) between the at least two polyphase conversion stages (2a, 2b) and the power grid (4).