Abstract: A method of operating a multilevel power converter includes using, through a processing device, a model of an electrical circuit that includes a plurality of switching devices, a plurality of flying capacitors, and an AC terminal. The method also includes regulating a voltage level of the AC terminal through selecting, at least partially based on the model, a possible charging state of the electrical circuit. Each possible switching state has a voltage level that at least partially corresponds to a commanded voltage level for the AC terminal. The method further includes selecting, at least partially based on the model of the electrical circuit and at least partially based on the selected possible switching state, a charging state from a plurality of possible charging states. The method also includes setting the switching state of the electrical circuit at least partially based on the selected charging state of the electrical circuit.

Abstract: A wind turbine includes a rotor, a plurality of rotor blades coupled to the rotor, and a blade pitch control system coupled to each rotor blade. A computer-implemented method for controlling the wind turbine includes determining at least one pitch position for a first blade. The method also includes determining whether there is a malfunction of the blade pitch control system associated with the first blade. The method further includes predicting a rotor imbalance using a model of at least a portion of the wind turbine. The method also includes comparing the predicted rotor imbalance with a predetermined threshold value. The method further includes one of regulating the pitch position for the second blade such that the predicted rotor imbalance is restored to a value below the predetermined threshold and regulating a pitch position for a second blade such that the predicted rotor imbalance does not exceed the predetermined threshold.

Abstract: A wind turbine system, comprising a tower, a plurality of blades, a rotor supported by the tower and rotatably coupled to the plurality of blades, a pitch control device for regulating pitch angles of the plurality of blades, a torque control device for regulating torque of the rotor, a processing subsystem programmed to slow down the wind turbine system by using the torque control device alone to slow down the rotor when the torque control device is fully capable of slowing down the rotor, and using both the torque control device and the pitch control device to slow down the rotor when the torque control device alone is not fully capable of slowing down the rotor.

Abstract: A method of operating a multilevel power converter includes using, through a processing device, a model of an electrical circuit that includes a plurality of switching devices, a plurality of flying capacitors, and an AC terminal. The method also includes regulating a voltage level of the AC terminal through selecting, at least partially based on the model, a possible charging state of the electrical circuit. Each possible switching state has a voltage level that at least partially corresponds to a commanded voltage level for the AC terminal. The method further includes selecting, at least partially based on the model of the electrical circuit and at least partially based on the selected possible switching state, a charging state from a plurality of possible charging states. The method also includes setting the switching state of the electrical circuit at least partially based on the selected charging state of the electrical circuit.

Abstract: A wind turbine includes a rotor, a plurality of rotor blades coupled to the rotor, and a blade pitch control system coupled to each rotor blade. A computer-implemented method for controlling the wind turbine includes determining at least one pitch position for a first blade. The method also includes determining whether there is a malfunction of the blade pitch control system associated with the first blade. The method further includes predicting a rotor imbalance using a model of at least a portion of the wind turbine. The method also includes comparing the predicted rotor imbalance with a predetermined threshold value. The method further includes one of regulating the pitch position for the second blade such that the predicted rotor imbalance is restored to a value below the predetermined threshold and regulating a pitch position for a second blade such that the predicted rotor imbalance does not exceed the predetermined threshold.

Abstract: A wind turbine system, comprising a tower, a plurality of blades, a rotor supported by the tower and rotatably coupled to the plurality of blades, a pitch control device for regulating pitch angles of the plurality of blades, a torque control device for regulating torque of the rotor, a processing subsystem programmed to slow down the wind turbine system by using the torque control device alone to slow down the rotor when the torque control device is fully capable of slowing down the rotor, and using both the torque control device and the pitch control device to slow down the rotor when the torque control device alone is not fully capable of slowing down the rotor.