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 energy conversion circuit comprising a switching stage with a positive DC voltage terminal (1), a negative DC voltage terminal (3), m?1 intermediate DC voltage terminals (2) m DC bus capacitors (5); and p linked cells consisting of m+1 switches (9) and at least one capacitor (10), connecting cell 1 to the positive DC voltage terminal (1), negative DC voltage terminals (3) and intermediate DC voltage terminals (2); and a multilevel converter, the output of which is connected to the AC voltage terminal (4), with a positive voltage terminal (12) and a negative voltage terminal (14) of the multilevel converter and m?1 intermediate voltage terminals of the multilevel converter (13), which are connected to the positive output terminal of the switching stage (6), to the negative output terminal of the switching stage (8), and to the m?1 intermediate output terminals of the switching stage (7), respectively.

Abstract: The invention is a multilevel electronic DC/AC or AC/DC power converter for n output voltage levels with a positive branch (POS) with a positive DC voltage terminal (2), a negative branch (NEG) with a negative DC voltage terminal (1), and an AC voltage terminal (3) connected to the positive branch (POS) and to the negative branch (NEG), DC bus capacitors (4) interconnected between positive (2) and negative (1) DC voltage terminals and an intermediate DC voltage terminal (5) connected between the two DC bus capacitors (4); a plurality of first external controlled semiconductors (6) and second external controlled semiconductors (7) and, at least, one high-current DC capacitor (11), at least two high-frequency and low-current capacitors (12) and one intermediate controlled semiconductor (8) connected between the intermediate DC voltage terminal (5) and an intermediate terminal (10) of an internal branch (INT) connected in parallel with each high-current DC capacitor (11).

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 energy conversion circuit comprising a switching stage with a positive DC voltage terminal (1), a negative DC voltage terminal (3), m?1 intermediate DC voltage terminals (2) m DC bus capacitors (5); and p linked cells consisting of m+1 switches (9) and at least one capacitor (10), connecting cell 1 to the positive DC voltage terminal (1), negative DC voltage terminals (3) and intermediate DC voltage terminals (2); and a multilevel converter, the output of which is connected to the AC voltage terminal (4), with a positive voltage terminal (12) and a negative voltage terminal (14) of the multilevel converter and m?1 intermediate voltage terminals of the multilevel converter (13), which are connected to the positive output terminal of the switching stage (6), to the negative output terminal of the switching stage (8), and to the m?1 intermediate output terminals of the switching stage (7), respectively.

Abstract: The invention relates to a multilevel electronic power converter for n output voltage levels with a positive branch (POS) with a positive DC voltage terminal (1), a negative branch (NEG) with a negative DC voltage terminal (2), and an AC voltage terminal (3) connected to the positive branch (POS) and to the negative branch (NEG); at least two DC bus capacitors (4) interconnected between the positive DC voltage terminal (1) and negative DC voltage terminal (2) and an intermediate DC voltage terminal (5) connected between the two DC bus capacitors (4); at least two first external semiconductors (6) and at least two second external semiconductors (7) with respective antiparallel diodes connected in series, respectively, in the positive (POS) and negative (NEG) branches between the DC voltage terminal (1, 2) and the AC voltage terminal (3); at least one high-current DC capacitor (11) connected between the positive (POS) and negative (NEG) branches, and at least two high-frequency low-current capacitors (12, 13

Abstract: The invention controls the network frequency via an active power reserve obtained by interacting in a coordinated manner with the speed regulation that acts on the power generated or on the pitch angle, to guarantee primary or secondary regulation across the whole range of wind speed.

Abstract: The present invention relates to a method and system for controlling a wind power installation connected to an electrical power grid, in case of a fault in said grid. In the electrical machines that form part of the wind power installation, generators and transformers, it is possible to change the impedance of the neutral closure introducing a plurality of active and passive elements. This limits the currents during the grid fault, thereby reducing the peak torque in the mechanical train of the wind turbines and allows guaranteeing compliance with the network connection requirements, as control of the active and reactive currents is maintained at all times.

Abstract: The present invention discloses a method for controlling a back-to-back converter when disturbances are produced in the grid which limit the capacity of the converter (105) on the side of the grid to control the voltage of the DC stage (106). In that event, the solution proposed is to pass complete or partial responsibility for controlling the voltage of the DC stage (106) to the converter (104) on the side of the generator (103).

Abstract: The present invention relates to a method and system for controlling a wind power installation connected to an electrical power grid, in case of a fault in said grid. In the electrical machines that form part of the wind power installation, generators and transformers, it is possible to change the impedance of the neutral closure introducing a plurality of active and passive elements. This limits the currents during the grid fault, thereby reducing the peak torque in the mechanical train of the wind turbines and allows guaranteeing compliance with the network connection requirements, as control of the active and reactive currents is maintained at all times.

Abstract: Method and system of control of the converter of an electricity generation facility of the type which comprises at least one electric generator, such as a wind generator, connected to an electricity network, in the presence of voltage sags in said network, the electric generator being a double-fed asynchronous generator formed by two windings, a winding in the stator, directly connected to the network, and a winding in the rotor which is fed on normal regime by said converter which imposes on it a predetermined voltage current called setpoint current. In the event of a voltage sag occurring, the converter imposes a new setpoint current which is the result of adding to the previous setpoint current a demagnetizing current which generates a flow in the rotor winding opposed to the free flow, consequently reducing the voltage in converter connectors.

Abstract: The invention controls the network frequency via an active power reserve obtained by interacting in a coordinated manner with the speed regulation that acts on the power generated or on the pitch angle, to guarantee primary or secondary regulation across the whole range of wind speed.

Abstract: The invention presents a structure for the conversion of direct current electric power into alternating current electric power, characterised in that it is simple, highly efficient and minimises the problem of electromagnetic compatibility. The circuit includes, in its first preferred embodiment, six switching elements governed by a command unit, four switches forming an H-bridge (T1, T2, T3, T4) and two auxiliary switches (T5D, T6D), and two auxiliary diodes (Daux1 and Daux2). The elements of the H-bridge switch at grid frequency, whereas T5D and T6D switch at high frequency by means of pulse width modulation (PWM), or other appropriate modulation techniques. The voltage of these auxiliary switching elements (T5D, T6D) is limited topologically to half the direct current input voltage (Vin), thereby reducing switching losses and resulting in a high performance converter.

Abstract: Method and system of control of the converter of an electricity generation facility of the type which comprises at least one electric generator, such as a wind generator, connected to an electricity network, in the presence of voltage sags in said network, the electric generator being a double-fed asynchronous generator formed by two windings, a winding in the stator, directly connected to the network, and a winding in the rotor which is fed on normal regime by said converter which imposes on it a predetermined voltage current called setpoint current. In the event of a voltage sag occurring, the converter imposes a new setpoint current which is the result of adding to the previous setpoint current a demagnetizing current which generates a flow in the rotor winding opposed to the free flow, consequently reducing the voltage in converter connectors.