A method for coordinate transformation of floating wind turbine floating body attitude measurement values

Abstract

The present invention discloses a method for coordinate transformation of the attitude measurement value of a floating body of a floating wind turbine. First, two coordinate systems are defined, namely, a fixed coordinate system of the floating body and a rotating coordinate system of the cabin. The attitude sensor is installed at the floating body or the base of a tower, and the installation direction is consistent with the initial yaw azimuth of the cabin. If the pitch and roll inclination angles during the operation of the floating wind turbine are both less than a threshold value, an approximate calculation method can be used to calculate the pitch and roll inclination angles of the cabin orientation; if the pitch or roll inclination angles during the operation of the floating wind turbine are greater than a threshold value, an accurate calculation method is required to calculate the pitch and roll inclination angles of the cabin orientation. The present invention converts the attitude sensor measurement value at the floating body or the base of the tower from the fixed coordinate system of the floating body to the rotating coordinate system of the cabin, so that the converted measurement value can be used for active control.

Description

Technical Field

[0001] The invention relates to the technical field of wind power generation, and in particular to a method for coordinate transformation of attitude measurement values ​​of a floating body of a floating wind turbine. Background Art

[0002] In order to suppress the pitch and roll motion of floating wind turbines, active control strategies are usually applied. It is usually necessary to install attitude sensors on the nacelle to obtain the pitch and roll angle information in the direction of the nacelle. However, the nacelle position has large vibrations, and the tower itself will bend. These factors interfere with the measurement of pitch and roll angles. If the attitude sensor is installed on the tower base or floating body, the interference can be reduced, but the nacelle orientation is inconsistent with the sensor installation direction. The pitch and roll angles of the nacelle orientation are not equal to the measured values ​​and cannot be used as feedback for active control. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to propose an accurate and reliable coordinate transformation method for the attitude measurement values ​​of a floating wind turbine buoy, so that the attitude sensor measurement values ​​on the tower base or the buoy can be used as feedback for active control.

[0004] To achieve the above object, the technical solution provided by the present invention is: a method for coordinate transformation of the measured value of the floating body attitude of a floating wind turbine, comprising the following steps:

[0005] Define the global coordinate system 0 as a fixed coordinate system for the floating body. The origin of the coordinate system is the center of gravity of the floating body, and the coordinate axes are oriented as follows: the Z axis is perpendicular to the horizontal plane, and the vertical direction is positive; the X and Y axes remain parallel to the horizontal plane; the X axis and the main axis of the initial yaw position of the cabin are in the same vertical plane, and the direction pointing downwind is positive; the positive direction of the Y axis is determined by the right-hand rule through the X and Z axes; the positive and negative pitch and roll angles of the floating body are determined by the right-hand rule; the attitude sensor is installed on the floating body or the tower base, and the installation direction is consistent with the initial yaw orientation of the cabin; in the global coordinate system 0, the pitch inclination angle of the cabin initial orientation measured by the attitude sensor is θ y0 , the roll angle is θ x0 ;

[0006] Define coordinate system 1 as the cabin rotation coordinate system. The origin of the coordinate system is the same as that of the global coordinate system 0. Its X and Y axes remain parallel to the horizontal plane and rotate with the cabin orientation.

[0007] During the operation of the floating wind turbine, the measured value of the yaw azimuth of the nacelle is Φ, that is, the yaw angle of the nacelle is Φ, which is the angle between the X-axis of the global coordinate system 0 and the X-axis of the coordinate system 1. When the pitch angle θ measured by the attitude sensor is y0 and the roll angle θ x0When both are less than the threshold, a two-dimensional coordinate rotation transformation is required, that is, the Z axis remains stationary, and the X and Y axes rotate with the Z axis as the rotation line, so as to change the pitch angle θ y0 and the roll angle θ x0 Converted to the corresponding pitch angle θ in coordinate system 1 y1 and the roll angle θ x1 , which is the pitch angle θ of the cabin after yaw y1 and the roll angle θ x1 The approximate value of; where the pitch angle θ of the cabin is y1 and the roll angle θ x1 The approximate calculation method is:

[0008] θ y1 =arctan(tanθ y0 cosΦ+tanθ x0 sinΦ)

[0009] θ x1 =arctan(-tanθ y0 sinΦ+tanθ x0 cosΦ)

[0010] When the pitch angle θ measured by the attitude sensor y0 Or the roll angle θ x0 When it is greater than the threshold, it is necessary to use three-dimensional coordinate rotation transformation for accurate calculation, that is, the origin remains stationary, and the X, Y, and Z axes rotate in three-dimensional space around the origin. At this time, the pitch angle θ of the cabin direction y1 and the roll angle θ x1 The exact calculation method is:

[0011]

[0012]

[0013] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0014] The present invention converts the measured values ​​of the attitude sensor at the float or the tower base from the fixed coordinate system of the float to the rotating coordinate system of the cabin, so that the converted measured values ​​can be used for active control, thereby solving the problem that the measured values ​​cannot be used as feedback for active control when the attitude sensor is installed on the float or the tower base. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a logical flow chart of the present invention.

[0016] Figure 2 This is a comparison chart of the approximate calculation and the precise calculation results when the pitch and roll angles measured by the attitude sensor are 5°.

[0017] Figure 3 This is a comparison chart of the approximate calculation and the precise calculation results when the pitch and roll angles measured by the attitude sensor are 10°.

[0018] Figure 4 This is a comparison chart of the approximate calculation and the precise calculation results when the pitch and roll angles measured by the attitude sensor are 15°. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0020] This embodiment provides a method for transforming the coordinates of the measured values ​​of the floating body attitude of a floating wind turbine. Figure 1 The specific situation is as follows:

[0021] Define the global coordinate system 0 as a fixed coordinate system for the floating body. The origin of the coordinate system is the center of gravity of the floating body, and the coordinate axes are oriented as follows: the Z axis is perpendicular to the horizontal plane, and the vertical direction is positive; the X and Y axes remain parallel to the horizontal plane; the X axis and the main axis of the initial yaw position of the cabin are in the same vertical plane, and the direction pointing downwind is positive; the positive direction of the Y axis is determined by the right-hand rule through the X and Z axes; the positive and negative pitch and roll angles of the floating body are determined by the right-hand rule; the attitude sensor is installed on the floating body or the tower base, and the installation direction is consistent with the initial yaw orientation of the cabin; in the global coordinate system 0, the pitch inclination angle of the cabin initial orientation measured by the attitude sensor is θ y0 , the roll angle is θ x0 ;

[0022] Define coordinate system 1 as the cabin rotation coordinate system. The origin of the coordinate system is the same as that of the global coordinate system 0. Its X and Y axes remain parallel to the horizontal plane and rotate with the cabin orientation.

[0023] During the operation of the floating wind turbine, the measured value of the yaw azimuth of the nacelle is Φ, that is, the yaw angle of the nacelle is Φ, which is the angle between the X-axis of the global coordinate system 0 and the X-axis of the coordinate system 1. When the pitch angle θ measured by the attitude sensor is y0 and the roll angle θ x0 When both are less than the threshold, a two-dimensional coordinate rotation transformation is required, that is, the Z axis remains stationary, and the X and Y axes rotate with the Z axis as the rotation line, so as to change the pitch angle θ y0 and the roll angle θ x0 Converted to the corresponding pitch angle θ in coordinate system 1 y1 and the roll angle θ x1 , which is the pitch angle θ of the cabin after yaw y1 and the roll angle θ x1 The approximate value of; where the pitch angle θ of the cabin is y1and the roll angle θ x1 The approximate calculation method is:

[0024] θ y1 =arctan(tanθ y0 cosΦ+tanθ x0 sinΦ)

[0025] θ x1 =arctan(-tanθ y0 sinΦ+tanθ x0 cosΦ)

[0026] When the pitch angle θ measured by the attitude sensor y0 Or the roll angle θ x0 When it is greater than the threshold, it is necessary to use three-dimensional coordinate rotation transformation for accurate calculation, that is, the origin remains stationary, and the X, Y, and Z axes rotate in three-dimensional space around the origin. At this time, the pitch angle θ of the cabin direction y1 and the roll angle θ x1 The exact calculation method is:

[0027]

[0028] See also Figure 2-Figure 4 As shown in the figure, the results of approximate calculation and accurate calculation are compared when the pitch and roll angles measured by the attitude sensor are 5°, 10°, and 15°, as shown below:

[0029] When the measured value of the pitch and roll inclination angle is 5°, when the cabin yaw angle changes from 0° to 180°, the maximum difference between the approximate calculation and the accurate calculation of the pitch and roll inclination angle of the cabin orientation is 0.0267°, and the relative error is 0.378%.

[0030] When the measured value of the pitch and roll inclination angle is 10°, when the cabin yaw angle changes from 0° to 180°, the maximum difference between the approximate and accurate calculation of the pitch and roll inclination angle of the cabin orientation is 0.209°, and the relative error is 1.48%.

[0031] When the measured value of the pitch and roll inclination angle is 15°, when the cabin yaw angle changes from 0° to 180°, the maximum difference between the approximate and accurate calculation of the pitch and roll inclination angle of the cabin orientation is 0.680°, and the relative error is 3.22%.

[0032] It can be seen that when the measured values ​​of the pitch and roll inclination angles are 15° or less, the pitch and roll inclination angles of the cabin orientation obtained by approximate calculation have a smaller error than the accurately calculated angles, meeting the requirements of engineering applications. If the measured values ​​of the pitch and roll inclination angles are greater than 15°, it is necessary to use the accurately calculated inclination angles to avoid excessive errors.

[0033] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for coordinate transformation of the measured value of the floating body attitude of a floating wind turbine, characterized in that: The following steps are involved: Define the global coordinate system 0 as the fixed coordinate system of the floating body. The origin of the coordinate system is the center of gravity of the floating body. The coordinate axes are oriented as follows: the Z axis is perpendicular to the horizontal plane, and the vertical direction is positive; the X and Y axes remain parallel to the horizontal plane; the X axis and the main axis of the initial yaw position of the cabin are in the same vertical plane, and the direction pointing downwind is positive; the positive direction of the Y axis is determined by the right-hand rule through the X and Z axes; the positive and negative pitch and roll angles of the floating body are determined by the right-hand rule; the attitude sensor is installed on the floating body or the tower base, and the installation direction is consistent with the initial yaw position of the cabin; In the global coordinate system 0, the pitch angle of the cabin's initial orientation measured by the attitude sensor is θ y0 , the roll angle is θ x0 ; Define coordinate system 1 as the cabin rotation coordinate system. The origin of the coordinate system is the same as that of the global coordinate system 0. Its X and Y axes remain parallel to the horizontal plane and rotate with the cabin orientation. During the operation of the floating wind turbine, the measured value of the yaw azimuth of the nacelle is Φ, that is, the yaw angle of the nacelle is Φ, which is the angle between the X-axis of the global coordinate system 0 and the X-axis of the coordinate system 1. When the pitch angle θ measured by the attitude sensor is y0 and the roll angle θ x0 When both are less than the threshold, a two-dimensional coordinate rotation transformation is required, that is, the Z axis remains stationary, and the X and Y axes rotate with the Z axis as the rotation line, so as to change the pitch angle θ y0 and the roll angle θ x0 Converted to the corresponding pitch angle θ in coordinate system 1 y1 and the roll angle θ x1 , which is the pitch angle θ of the cabin after yaw y1 and the roll angle θ x1 The approximate value of; where the pitch angle θ of the cabin is y1 and the roll angle θ x1 The approximate calculation method is: θ y1 =arctan(tanθ y0 cosΦ+tanθ x0 sinΦ) θ x1 =arctan(-tanθ y0 sinΦ+tanθ x0 cosΦ) When the pitch angle θ measured by the attitude sensor y0 Or the roll angle θ x0 When it is greater than the threshold, it is necessary to use three-dimensional coordinate rotation transformation for accurate calculation, that is, the origin remains stationary, and the X, Y, and Z axes rotate in three-dimensional space around the origin. At this time, the pitch angle θ of the cabin direction y1 and the roll angle θ x1 The exact calculation method is:

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