# US 10,767,628 B2 · Control of a wind turbine comprising multi-axial accelerometers

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- Number: US 10,767,628 B2
- Document ID: US10767628B2
- Status: Granted
- Kind: B2
- Application number: 16/088,268
- Filed: 2017-04-04
- Published: 2019-03-21
- Granted: 2020-09-08
- Earliest claimed: 2016-04-08
- Assignees: Vestas Wind Systems A/S
- Applicants: Vestas Wind Systems A/S
- Inventors: Tobias Gybel Hovgaard; Johnny Nielsen; Peter Fogh Odgaard
- Web page: https://patentgrep.com/patent/US10767628B2

## CPC

- F03D 7/0224: {Adjusting blade pitch}
- F03D 7/0272: {by measures acting on the electrical generator}
- F03D 7/0296: {to prevent, counteract or reduce noise emissions}
- F03D 7/04: Automatic control; Regulation
- F03D 13/20: Arrangements for mounting or supporting wind motors; Masts or towers for wind motors
- F03D 17/00: Monitoring or testing of wind motors, e.g. diagnostics (testing during commissioning of wind motors F03D13/30)
- G05B 17/02: electric
- F03D 1/00: Wind motors with rotation axis substantially parallel to the air flow entering the rotor (controlling thereof F03D7/02)
- F05B 2220/30: in turbines
- F05B 2240/221: with horizontal axis
- F05B 2240/30: Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
- F05B 2240/912: on a tower
- F05B 2260/71: as a function of flow velocity
- F05B 2260/74: by turning around an axis perpendicular the rotor centre line
- F05B 2260/80: Diagnostics
- F05B 2260/821: Parameter estimation or prediction
- F05B 2260/96: Preventing, counteracting or reducing vibration or noise
- F05B 2270/1032: Torque
- F05B 2270/1033: Power (if explicitly mentioned)
- F05B 2270/20: to optimise the performance of a machine
- F05B 2270/304: Spool rotational speed
- F05B 2270/334: Vibration measurements
- F05B 2270/335: Output power or torque
- F05B 2270/402: passive or reactive, e.g. using large wind vanes
- F05B 2270/807: Accelerometers
- Y02E 10/72: Wind turbines with rotation axis in wind direction
- Y02E 10/728: Onshore wind turbines
- F03D: WIND MOTORS
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The invention relates to control of a wind turbine comprising a plurality of multi-axial accelerometers mounted at different positions in the nacelle and/or in a top portion of the tower. The position and orientation of each accelerometer as mounted is obtained, accelerations in at least two different directions by each accelerometer are measured during operation of the wind turbine. From a number of predetermined mode shapes for the movement of the wind turbine is then determined an absolute position of at least one of the accelerometers during operation of the wind turbine based on the measured accelerations, the mount position and orientation of each accelerometer and the pre-determined mode shapes. Hereby a more precise absolute position during operation is obtained which can be used in the controlling of the turbine.

## Claims

### Claim 1

A method of controlling a wind turbine, the wind turbine comprising a tower supporting a nacelle and a rotor with a number of pitch-adjustable rotor blades, the wind turbine further comprising a control system for changing the pitch of the rotor blades and/or the generator torque, and a plurality of multi-axial accelerometers mounted at different positions in the nacelle and/or in a top portion of the tower, each accelerometer being mounted in a defined orientation, the method comprising:
obtaining the position and orientation of each accelerometer as mounted;
measuring accelerations in at least two different directions by each accelerometer during operation of the wind turbine;
obtaining a number of pre-determined mode shapes for the movement of the wind turbine based at least on dimensions of the tower and a weight of the nacelle and the rotor as supported by the tower, the number of pre-determined mode shapes including at least one natural mode shape in a plane corresponding to fore-aft movements and at least one natural mode shape in a plane corresponding to side-side movements;
determining an absolute position of at least one of the accelerometers during operation of the wind turbine based on the measured accelerations, the mount position and orientation of each accelerometer and the pre-determined mode shapes;
determining a control parameter of the wind turbine as a function of the determined absolute position; and
controlling the wind turbine according to the control parameter.

### Claim 2 (depends on 1)

The method of controlling according to claim 1 further comprising determining a velocity of at least one of the accelerometers during operation of the wind turbine based on the measured accelerations, the position and orientation of each accelerometer as mounted, and the mode shapes.

### Claim 3 (depends on 1)

The method of controlling according to claim 1, wherein the number of pre-determined mode shapes of the wind turbine is determined from the natural mode shapes of a beam fixed in one end and with a point mass at an opposite free end.

### Claim 4 (depends on 1)

The method of controlling according to claim 1, wherein the number of pre-determined mode shapes comprises at least the two first natural mode shapes in a plane corresponding to fore-aft movements of the wind turbine.

### Claim 5 (depends on 1)

The method of controlling according to claim 1, wherein the number of mode shapes comprises at least the two first natural mode shapes in a plane corresponding to side-side movements of the wind turbine.

### Claim 6 (depends on 1)

The method of controlling according to claim 1, further comprising estimating a thrust force acting on the rotor blades by the wind based on the determined absolute position of the at least one of the accelerometers during operation of the wind turbine.

### Claim 7 (depends on 5)

The method of controlling according to claim 5 further comprising estimating a wind speed based on the estimated thrust and parameters including a rotational speed of the rotor blades, a pitch angle of each of the rotor blades, and an air density.

### Claim 8 (depends on 1)

The method of controlling according to claim 1, wherein the absolute position of the accelerometer(s) is determined by means of a Kalman filtering.

### Claim 9 (depends on 1)

The method of controlling according to claim 1, wherein the multi-axial accelerometers are each mounted with two axes of measurement arranged in an essentially horizontal plane.

### Claim 10 (depends on 1)

The method of controlling according to claim 1, wherein at least two of the plurality of the multi-axial accelerometers are mounted such that the axes of measurement of the multi-axial accelerometers are oriented in the same directions.

### Claim 11 (depends on 1)

The method of controlling according to claim 1, wherein at least two of the plurality of the multi-axial accelerometers are mounted such that the axes of measurement of the multi-axial accelerometers are oriented differently.

### Claim 12 (depends on 1)

The method of controlling according to claim 1, wherein a first accelerometer is mounted at a first position in a first vertical plane parallel to an axis of rotation of the rotor blades of the wind turbine, and a second accelerometer is mounted at a second position in a second vertical plane parallel to the axis of rotation, the first plane being different from the second plane.

### Claim 13 (depends on 1)

The method of controlling according to claim 1, wherein a first accelerometer is mounted at a first position at a first plane perpendicular to an axis of rotation of the rotor blades of the wind turbine, and a second accelerometer is mounted at a second position in a second plane perpendicular to the axis of rotation, the first plane being different from the second plane.

### Claim 14 (depends on 1)

The method of controlling according to claim 1, where the control parameter comprises a pitch parameter of one or more of the rotor blades and the controlling of the wind turbine comprises pitching one or more of the blades according to the pitch parameter.

### Claim 15 (depends on 1)

The method of controlling according to claim 1, where the control parameter comprises a torque parameter and the controlling of the wind turbine comprises adjusting the torque of a wind turbine generator according to the torque parameter.

### Claim 16

A control system for a wind turbine comprising a tower supporting a nacelle and a rotor with a number of pitch-adjustable rotor blades, the wind turbine further comprising a plurality of multi-axial accelerometers mounted at different positions in the nacelle and/or in a top portion of the tower, each accelerometer being mounted in a defined orientation, the control system being configured to perform the steps of:
obtaining the position and orientation of each of a plurality of multi-axial accelerometers as mounted;
receiving data of the acceleration in at least two different directions as measured by each of the accelerometers during operation of the wind turbine;
obtaining a number of pre-determined mode shapes for the movement of the wind turbine based at least on dimensions of the tower and a weight of the nacelle and rotor as supported by the tower, the number of pre-determined mode shapes including at least one natural mode shape in a plane corresponding to fore-aft movements and at least one natural mode shape in a plane corresponding to side-side movements;
determining an absolute position of at least one of the accelerometers during operation of the wind turbine based on the measured accelerations, the mount position and orientation of each accelerometer and the pre-determined mode shapes;
determining a control parameter of the wind turbine as a function of the determined absolute position; and
controlling the wind turbine according to the control parameter.

### Claim 17 (depends on 16)

A wind turbine comprising a tower supporting a nacelle and a rotor with a number of pitch-adjustable rotor blades, the wind turbine further comprising a plurality of multi-axial accelerometers mounted at different positions in the nacelle and/or in a top portion of the tower, each accelerometer being mounted in a defined orientation, and a control system according to claim 16.

### Claim 18 (depends on 1)

A computer program configured when executed for controlling a processor to perform the method according to claim 1.