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
The present invention relates to 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.
Claims20
A method for controlling a wind turbine in response to a rotor stop signal, the wind turbine comprises a rotor with one or more pitch adjustable rotor blades;
- and wherein upon receiving the rotor stop signal, the rotor speed is reduced by a stop controller controlling the pitch adjustable rotor blades towards a feathering position in a stopping process, and wherein the stop controller is arranged to pitch the 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;
- adding an envelope band to the desired pitch angles by adding a positive value and a negative value thereby defining an upper band value and a lower band value;
- and
- operating the stop controller to:
- move the pitch adjustable rotor blade at a selected pitch rate among the number of pre-set pitch rates until the pitch angle signal is outside a pitch angle value defined by the envelope band;
- when the pitch angle signal is larger than the upper band value, change the selected pitch rate to a lower pitch rate among the number of pre-set pitch rates;
- and
- when the pitch angle signal is smaller than the lower band value, change the selected pitch rate to a higher pitch rate among the number of pre-set pitch rates.
(canceled)
A wind turbine comprising a control system and a rotor with at least 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 pitch adjustable rotor blades towards a feathering position in a stopping process, and wherein the stop controller is arranged to pitch the 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;
- add an envelope band to the desired pitch angles by adding a positive value and a negative value thereby defining an upper band value and a lower band value;
- and
- move the pitch adjustable rotor blade at a selected pitch rate among the number of pre-set pitch rates until the pitch angle signal is outside a pitch angle value defined by the envelope band;
- when the pitch angle signal is larger than the upper band value, change the selected pitch rate to a lower pitch rate among the number of pre-set pitch rates;
- and
- when the pitch angle signal is smaller than the lower band value, change the selected pitch rate to a higher pitch rate among the number of pre-set pitch rates.
A computer program product comprising software code which, when executed on a data processing system, 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:
- accessing desired pitch angles of a stopping process whereby, upon receiving a rotor stop signal, the rotor speed is reduced by a stop controller controlling the pitch adjustable rotor blades towards a feathering position in the stopping process;
- adding an envelope band to the desired pitch angles by adding a positive value and a negative value thereby defining an upper band value and a lower band value;
- and
- operating the stop controller to:
- move the pitch adjustable rotor blade at a selected pitch rate among a number of pre-set pitch rates until the pitch angle signal is outside a pitch angle value defined by the envelope band, wherein the number of pre-set pitch rates includes a first pitch rate and a second pitch rate, the second pitch rate being lower than the first pitch rate;
- when the pitch angle signal is larger than the upper band value, change the selected pitch rate to a lower pitch rate among the number of pre-set pitch rates;
- and
- when the pitch angle signal is smaller than the lower band value, change the selected pitch rate to a higher pitch rate among the number of pre-set pitch rates.
Dependencies are inferred from the claim text.