Abstract: Wind turbine comprising a plurality of converters, which are dynamically switched between at least a first standby state, a second running state, and a third state with an active direct current link. Converters are switched from the first standby state to the third state when a required reactive power is higher than a reactive power capability of converters on the second running state and when a voltage transient occurs.

Abstract: Inertia control system for a wind turbine comprising a rotor (5), generator (12) driven by the rotor (5) that interacts with a power converter (13) to generate electricity, a wind turbine controller (15) that comprises a blade pitch controller (19) and a generated power controller (18), a controller for the power converter (14) that interacts with the wind turbine controller (15), characterized because it comprises an inertia emulation block (17) that generates an extra power signal (32) negatively proportional to the frequency change rate (23) that is added to the power reference of the wind turbine generated power controller (15) and adapts the rotational speed reference of the wind turbine controller (15) according to the grid frequency (21) to prevent distortion in the active power output after adding or subtracting power in proportion to the frequency change rate (23).

Abstract: Wind turbine comprising a plurality of converters, which are dynamically switched between at least a first standby state, a second running state, and a third state with an active direct current link. Converters are switched from the first standby state to the third state when a required reactive power is higher than a reactive power capability of converters on the second running state and when a voltage transient occurs.

Abstract: The present invention is directed to a method of reducing a mechanical load on the occurrence of voltage dip in the wind turbines. The wind turbine generator controller and the converter control unit work in combination to control the oscillation generated due to voltage dip in the wind turbine 100. The method applies a ramp in power recovery to allow the enhanced DTD damp oscillations before the peak in torque happens. The method involves the step of: delivering a maximum active power value by the converter control unit to the wind turbine generator controller. Next step is setting a saturation value for the set points to enhance the drive train limits. In the next step, ramping is applied to the power set points of the wind turbine generator. And finally an enhanced drive train damping s applied to the ramped value of the power in order to reduce the mechanical load in the wind turbine and to damp the oscillation in the wind turbine generator.

Abstract: Inertia control system for a wind turbine comprising a rotor (5), generator (12) driven by the rotor (5) that interacts with a power converter (13) to generate electricity, a wind turbine controller (15) that comprises a blade pitch controller (19) and a generated power controller (18), a controller for the power converter (14) that interacts with the wind turbine controller (15), characterized because it comprises an inertia emulation block (17) that generates an extra power signal (32) negatively proportional to the frequency change rate (23) that is added to the power reference of the wind turbine generated power controller (15) and adapts the rotational speed reference of the wind turbine controller (15) according to the grid frequency (21) to prevent distortion in the active power output after adding or subtracting power in proportion to the frequency change rate (23).

Abstract: Method and module for measuring the rate of change of frequency of a waveform related to a converter unit of a wind turbine generator, comprising: measuring an instantaneous value of said rate of change of frequency of the waveform, calculating a first filtered value of said rate of change of frequency, said first filtered value having good accuracy but low time response, and calculating a second filtered value of said rate of change of frequency said second filtered value having a good time response but low accuracy, comparing said first and second filtered values and selecting that an output value of said measured rate of change is based on said first or second filtered values depending on said comparison.

Abstract: The present invention is directed to a method of reducing a mechanical load on the occurrence of voltage dip in the wind turbines. The wind turbine generator controller and the converter control unit work in combination to control the oscillation generated due to voltage dip in the wind turbine 100. The method applies a ramp in power recovery to allow the enhanced DTD damp oscillations before the peak in torque happens. The method involves the step of: delivering a maximum active power value by the converter control unit to the wind turbine generator controller. Next step is setting a saturation value for the set points to enhance the drive train limits. In the next step, ramping is applied to the power set points of the wind turbine generator. And finally an enhanced drive train damping s applied to the ramped value of the power in order to reduce the mechanical load in the wind turbine and to damp the oscillation in the wind turbine generator.

Abstract: Method and module for measuring the rate of change of frequency of a waveform related to a converter unit of a wind turbine generator, comprising: measuring an instantaneous value of said rate of change of frequency of the waveform, calculating a first filtered value of said rate of change of frequency, said first filtered value having good accuracy but low time response, and calculating a second filtered value of said rate of change of frequency said second filtered value having a good time response but low accuracy, comparing said first and second filtered values and selecting that an output value of said measured rate of change is based on said first or second filtered values depending on said comparison.