Control of the rotational speed of a wind turbine which is impeded to export electrical power to an electricity network

A device for controlling the rotational speed of a rotor of a wind turbine that feeds electrical power into an electricity network, the device, comprising:

• a first input node for receiving a first signal, the first signal is indicative of an actual rotational speed of the rotor;
• a second input node for receiving a second signal, the second signal is indicative of a reference rotational speed for the rotor;
• a detection unit for detecting a defective operational state in which the wind turbine is impeded to export electrical power to the electricity network;
• a control unit for providing a reference signal for a characteristic operational parameter of the wind turbine based on the first signal and based on the second signal, the characteristic operational parameter is indicative of the rotational speed of the rotor;
• and
• a pulse generator connected to the detection unit and to the integral control element and is adapted to send a kick pulse to the integral control element in response to the detection of the defective operational state,
• wherein the control unit includes a proportional control element and an integral control element.

A wind turbine for generating electric power, the wind turbine comprising

• a rotor including a blade, the rotor is rotatable around a rotational axis and the blade extends radially with respect to the rotational axis;
• a generator mechanically coupled to the rotor, the generator generates electrical power from a rotational movement of the rotor;
• and
• a device for controlling the rotational speed of the rotor, the device comprising:
• a first input node for receiving a first signal, the first signal is indicative of an actual rotational speed of the rotor;
• a second input node for receiving a second signal, the second signal is indicative of a reference rotational speed for the rotor;
• a detection unit for detecting a defective operational state in which the wind turbine is impeded to export electrical power to the electricity network;
• a control unit for providing a reference signal for a characteristic operational parameter of the wind turbine based on the first signal and based on the second signal, the characteristic operational parameter is indicative of the rotational speed of the rotor;
• and
• a pulse generator connected to the detection unit and to the integral control element and is adapted to send a kick pulse to the integral control element in response to the detection of the defective operational state,
• wherein the control unit includes a proportional control element and an integral control element.

A method for controlling the rotational speed of a rotor of a wind turbine that feeds electrical power into an electricity network, the method comprising:

• receiving a first signal, the first signal indicative of an actual rotational speed of the rotor;
• receiving a second signal, the second signal indicative of a reference rotational speed for the rotor;
• detecting a defective operational state in which the wind turbine is impeded to export electrical power to the electricity network;
• providing a reference signal for a characteristic operational parameter of the wind turbine based on the first signal and based on the second signal, the characteristic operational parameter is indicative of the rotational speed of the rotor;
• sending a kick pulse from a pulse generator to an integral control element of a control unit;
• and
• integrating the kick pulse such that the reference signal for the characteristic operational parameter of the wind turbine is changed in response to the detection of the defective operational state, the change of the reference signal causes the rotor to change its rotational speed.