Stopping a wind turbine rotor using pre-set pitch rates
AssigneeVestas Wind Systems A/S
InventorsKeld Hammerum, Christian Jeppesen, Jon Sowman
Life of this patent
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Abstract
Control of a wind turbine in a stop process where a stop controller is used to pitch the blades at a number of pre-set pitch rates including a first pitch rate and a second pitch rate. The stop controller is arranged to access desired pitch angles of the stopping process and add an envelope band to the desired pitch angles. In the stop process, pitching at a selected pitch rate among the number of pre-set pitch rates is performed, and the pitch rate is changed according to criteria to keep the pitch value within the envelope band.
Claims19
A method for controlling a wind turbine, the wind turbine comprises a rotor with one or more pitch adjustable rotor blades and a stop controller configured to control the one or more pitch adjustable rotor blades towards a feathering position in response to a rotor stop signal as part of a stopping process that reduces speed of the rotor, and wherein the stop controller is arranged to pitch the one or more pitch adjustable rotor blades at a number of pre-set pitch rates including a first pitch rate and a second pitch rate, the second pitch rate being lower than the first pitch rate, wherein the method comprises:
- accessing desired pitch angles of the stopping process, the desired pitch angles defining a pitch trajectory across an entire duration of the stopping process;
- defining an envelope band of the pitch trajectory by adding positive values and negative values to the desired pitch angles, thereby defining an upper band and a lower band of the pitch trajectory across the entire duration, or until a termination criterion has been reached;
- and
- operating the stop controller to:
- move the one or more pitch adjustable rotor blades at a selected pitch rate among the number of pre-set pitch rates until a pitch angle signal is outside a pitch angle value defined by the envelope band such that:
- when the pitch angle signal is larger than the upper band at a specific time, the selected pitch rate is changed to the second pitch rate;
- and
- when the pitch angle signal is smaller than the lower band at a specific time, the selected pitch rate is changed to the first pitch rate.
A wind turbine comprising a control system and a rotor with one or more pitch adjustable rotor blades, the control system being arranged for controlling the wind turbine in response to a rotor stop signal, wherein the control system comprises:
- a stop controller arranged for controlling the one or more pitch adjustable rotor blades towards a feathering position in response to the rotor stop signal as part of a stopping process, and wherein the stop controller is arranged to pitch the one or more pitch adjustable rotor blades at a number of pre-set pitch rates including a first pitch rate and a second pitch rate, the second pitch rate being lower than the first pitch rate;
- wherein the stop controller is arranged to:
- access desired pitch angles of the stopping process, the desired pitch angles defining a pitch trajectory across an entire duration of the stopping process;
- define an envelope band of the pitch trajectory by adding positive values and negative values to the desired pitch angles, thereby defining an upper band and a lower band of the pitch trajectory across the entire duration, or until a termination criterion has been reached;
- move the one or more pitch adjustable rotor blades at a selected pitch rate among the number of pre-set pitch rates until a pitch angle signal is outside a pitch angle value defined by the envelope band such that:
- when the pitch angle signal is larger than the upper band at a specific time, the selected pitch rate is changed to the second pitch rate;
- and
- when the pitch angle signal is smaller than the lower band at a specific time, the selected pitch rate is changed to the first pitch rate.
A computer program product comprising a non-transitory computer readable medium having software code which, is adapted to control a wind turbine comprising a rotor with one or more pitch adjustable rotor blades, the computer program product being adapted to perform an operation for controlling the wind turbine, the operation comprising:
- implementing a stopping process by a stop controller in response to a rotor stop signal, the stopping process reducing speed of the rotor by controlling the one or more pitch adjustable rotor blades towards a feathering position at a number of pre-set pitch rates including a first pitch rate and a second pitch rate, the second pitch rate being lower than the first pitch rate, wherein the stop controller is configured to:
- access desired pitch angles of the stopping process, the desired pitch angles defining a pitch trajectory across an entire duration of the stopping process;
- define an envelope band of the pitch trajectory by adding positive values and negative values thereby defining an upper band and a lower band of the pitch trajectory across the entire duration, or until a termination criterion has been reached;
- and
- move the one or more pitch adjustable rotor blades at a selected pitch rate among the number of pre-set pitch rates until a pitch angle signal is outside a pitch angle value defined by the envelope band such that:
- when the pitch angle signal is larger than the upper band at a specific time, the selected pitch rate is changed to the second pitch rate;
- and
- when the pitch angle signal is smaller than the lower band at a specific time, the selected pitch rate is changed to the first pitch rate.
Dependencies are inferred from the claim text.