Techniques are described for operating a wind power facility in order to provide reactive power support to a power grid. The wind power facility may be a wind turbine or a wind power plant. An exemplary method includes increasing an amount of reactive power injected into the power grid, decreasing an amount of active power injected into the power grid by a certain amount, and dissipating and/or storing substantially the certain amount of active power.

A rectifier includes a rectification MOSFET that performs rectification, a comparator formed by connecting a drain of the rectification MOSFET to a non-inverting input terminal and a source to an inverting input terminal, and a control circuit that performs an on/off control of the rectification MOSFET using an output of the comparator. The control circuit includes a shut-off MOSFET that disconnects a drain of the rectification MOSFET and a non-inverting input terminal of the comparator from each other, and a shut-off circuit that turns off the shut-off MOSFET to electrically disconnect the drain of the rectification MOSFET and the non-inverting input terminal of the comparator from each other when the drain voltage of the rectification MOSFET is equal to or higher than a predetermined first voltage.

A method is provided of protecting a wind turbine with a doubly-fed induction generator (DFIG) against a sub-synchronous resonance (SSR) event acting on the wind turbine. A plurality of power-output values or current-output values is measured over a given period of time that corresponds to a measurement cycle. It is determined whether power-output values or current-output-values measured in the at-least-one measurement cycle are indicative of an SSR-event critical for further operation of the wind turbine. The wind turbine is shut down if the measured power-output values or current-output values are indeed indicative of an SSR-event critical for operation of the wind turbine.

A power generation system is provided. The system includes a prime mover for transforming a first energy to a second energy. The system also includes an induction generator operatively coupled to the prime mover and configured to generate electrical power using the second energy. The system further includes an inverter electrically coupled to the induction generator for controlling a terminal voltage of the induction generator during a grid-loss condition. The system also includes a power dissipating device operatively coupled to the inverter for dissipating power generated by the induction generator during the grid-loss condition.

A power generation system includes a generator operatively coupled to an engine for generating electrical power and supplying the electrical power to a grid. Further, the power generation system includes a resistive braking system operatively coupled between the generator and the grid. The resistive braking system includes a mechanical switch connected in parallel with a resistor, and a controller for, in response to a grid event, controlling power from the engine and operating the mechanical switch to redirect current between the mechanical switch and the parallel connected resistor.

An apparatus with load dump protection incorporates first and second half-bridge circuits, first and second comparators, and first and second clamping circuits. The first comparator compares a supply voltage with a first set voltage and generates a first comparison signal while the supply voltage exceeds the first set voltage. The second comparator compares the supply voltage with a second set voltage and generates a second comparison signal while the supply voltage exceeds the second set voltage. The first clamping circuit divides the supply voltage and provides a divided voltage to the first half-bridge circuit in response to the second comparison signal. The second clamping circuit divides the supply voltage and provides a divided voltage to the second half-bridge circuit in response to the second comparison signal.

A rectifier includes a rectification MOSFET that performs rectification, a comparator formed by connecting a drain of the rectification MOSFET to a non-inverting input terminal and a source to an inverting input terminal, and a control circuit that performs an on/off control of the rectification MOSFET using an output of the comparator. The control circuit includes a shut-off MOSFET that disconnects a drain of the rectification MOSFET and a non-inverting input terminal of the comparator from each other, and a shut-off circuit that turns off the shut-off MOSFET to electrically disconnect the drain of the rectification MOSFET and the non-inverting input terminal of the comparator from each other when the drain voltage of the rectification MOSFET is equal to or higher than a predetermined first voltage.

An energy production plant has a drive train including a differential gear (14) with three drive and power take-off assemblies, a first drive assembly being connected to a drive shaft, a power take-off assembly being connected to a generator (13) and a second drive assembly being connected to a differential drive assembly (16). The differential gear (14) is a planetary gear. Both an emergency brake (4) and a service brake (20) are located in the drive train. In the event of a power failure, grid fault or an emergency shutdown, the service brake (20) is activated such that the torque acting on the rotor (1) supplied by the drive train remains substantially constant for a period of at least 0.5 seconds.

A method for controlling a bridge rectifier which includes active switching elements is provided, in which, during normal operation, at least one of the active switching elements is controlled using a voltage signal, the voltage of which is changed from a first voltage value to a second voltage value within at least one switching time. The at least one switching time is extended by a predefinable time period if load shedding at the bridge rectifier is determined. Also described is a corresponding rectifier system and a computer program product.

A motor vehicle electrical system which includes an electric machine, an active bridge rectifier, and at least one control device, the at least one control device being configured for converting an alternating voltage which is output by the electric machine at a number of phase connections into a direct voltage by controlling active switching elements of the bridge rectifier. An arrangement is provided configured for initiating a short circuit of at least two of the phase connections as soon as a signal characterizing the direct voltage exceeds an upper threshold value, and for deactivating the short circuit as soon as the signal characterizing the direct voltage subsequently falls below a lower threshold value. An evaluation device is provided configured for detecting a value of the direct voltage, for filtering the detected value, and for providing the filtered value as the signal characterizing the direct voltage.