WO2013083053A1

WO2013083053A1 - Calibration method and calibration system for heliostat of solar power station

Info

Publication number: WO2013083053A1
Application number: PCT/CN2012/086006
Authority: WO
Inventors: 孙海翔; 朱亮
Original assignee: Sun Haixiang
Priority date: 2011-12-08
Filing date: 2012-12-06
Publication date: 2013-06-13
Also published as: CN102495640A; CN102495640B

Abstract

A heliostat calibration method for a solar power station. The method: acquiring a distance offset (e_i) between the center position of a reflected light spot of a heliostat (2) and the center of a receiver (1) via a movement of an image sensor (3), and controlling the heliostat (2) to rotate to a nominal position (G_i); determining the size of the offset of the heliostat (2) by comparing the distance offset (e_i) to a set offset value (d_i), when the offset of the heliostat (2) is small, calibrating only a smaller number of calibration errors would suffice, and when the offset of the heliostat (2) is great, then calibrating a greater number of calibration errors. The heliostat calibration method determines the center position of the reflected light spot of the heliostat (2) via the image sensor set, and allows for rapid calibration movement, for reduced mechanical error, and for increased calibration precision. Also, the heliostat calibration method performs calibration by a scheme of first determining the size of the offset of the heliostat (2), then determining a calibration parameter, thus increasing the calibration efficiency and calibration precision.

Description

Description of the heliostat calibration method and calibration system of solar power station

The invention belongs to the field of solar power generation, and particularly relates to a heliostat calibration method and a calibration system for a solar power station.

Background technique

In a central tower receiver power station, the receiver at the top of the tower receives sunlight from the heliostat group. The receiver converts incident radiant energy to output high-pressure, high-temperature steam, which can then be sent to a turbine for electrical power generation. Heliostats are typically installed on the ground around the tower. Each heliostat has a rigid reflective surface that tracks the sun, and the surface uses a sunny position during the day to keep the reflected sunlight moving to the receiver. It is necessary to track the sun with high accuracy and reduce the reflected light that overflows around the receiver. Therefore, it is a technical problem that those skilled in the art need to solve to provide a heliostat calibration system capable of accurately tracking the sun to achieve higher efficiency and less loss.

In order to solve the above problems, the calibration methods commonly used in the existing heliostat calibration system are: the spatial position of the spot reflected by the heliostat reflected by the image sensor, that is, the center position of the spot, and the corresponding date The rotation angle of the mirror, where the rotation angle is the pitch angle Φ and/or the pan angle ω of the specified , mirror, and the error value of the calibration required for the heliostat is obtained. According to the obtained error value, the parameters of the heliostat in the database are updated. According to these parameters and the position of the receiver and the sun, the angle at which the heliostat reflects the sunlight on the receiver is calculated and the tracking is started. However, in the above calibration method, first, the number of errors η to be calibrated is determined, and calibration can be performed by obtaining at least η/2 spot center positions and rotation angle information of the heliostat. Since the heliostat error to be calibrated cannot be known, in order to accurately calibrate, more calibration errors are usually selected for calibration. Thus, multiple rotations of the heliostat are required to obtain multiple spot center positions and heliostat rotations. Angle information, the mechanical error is introduced by the multiple trajectory rotation of the heliostat during the calibration process, and the calibration accuracy is reduced.

For example, Chinese Patent No. CN101918769A discloses a heliostat calibration and tracking control method in a central tower receiver solar power plant, which includes a heliostat field that reflects sunlight to a receiver, and a camera that points to a mirror group of at least a certain day. . The camera is configured to produce multiple sunlight images that are reflected by the heliostats. The system is calibrated by the above calibration method. During the calibration process, the process of determining the center position of the spot is as follows: First, the spot reflected by the heliostat is captured by the camera, and the heliostat is in the initial configuration, in order to enable the camera to find the center position of the reflected spot of the heliostat, the control system controls The heliostat rotates, and finally the heliostat rotates until the camera captures the center of the spot. At this time, a set of spot center position and heliostat rotation angle information values are obtained. To calibrate n errors, at least η is required. The above process is performed /2 times to obtain the η/2 group spot center position and the heliostat rotation angle information value and then calibrated. The calibration process is more complicated. In addition, the calibration system requires the camera fixed in the field of heliostats to obtain the center of the reflected spot of the heliostat through the continuous rotation of the heliostat. Figure 1 shows the heliostat rotation performed when the center sample of the spot is obtained using the camera. The trajectory map, the orientation of the heliostat is controlled by two rotation angles, a pan angle ω and a pitch angle φ. The pan angle ω is represented along the horizontal axis. The pitch angle φ is represented along the vertical axis. From the trajectory map, it can be concluded that the system requires multiple rotations of the heliostat to reach the position where the camera can detect the center of the spot. The reflected spot of the heliostat cannot be irradiated on the receiver, which affects the power generation efficiency, and the multiple trajectory rotation of the heliostat introduces a mechanical error, and the calibration accuracy is lowered. In addition, in larger power plants, the rotation of a large number of heliostats consumes the electrical energy of the calibrated motor that controls the rotation of the heliostat. For example, in US Pat. No. 20100139644, although the trajectory of the heliostat is simplified compared to CN101918769A during calibration, in order to obtain the position of the heliostat reflection spot contour, it is still necessary to control the system to control a large number of heliostats to be able to capture the camera. Where it is; thus, the reflected spot of the heliostat cannot be illuminated on the receiver, affecting the power generation effectiveness. Moreover, in the above two schemes, regardless of the error of the heliostat parameter, the heliostat needs to be rotated to multiple positions to obtain multiple sets of data for calibration, which affects the power generation efficiency.

Summary of the invention

Therefore, the technical problem to be solved by the present invention is that the existing heliostat calibration method has low calibration efficiency and low calibration accuracy, and further provides a heliostat calibration method for a solar power station that determines the number of calibration errors according to the error size. .

In order to solve the above technical problem, the present invention discloses a calibration method for a heliostat calibration system of a solar power plant, which comprises the following steps: a. The control unit controls the rotation of the heliostat to align the reflected image of the heliostat Nominal position G _1;

b. The image sensor group collects a reflection image of the heliostat, the control unit determines a center position U of the reflection image of the heliostat according to the image acquired by the image sensor group, and the center position U of the reflection image is The nominal position Gi is compared, determining the distance deviation ei of the center position U of the reflected image from the nominal position Gi and the corresponding heliostat; simultaneously obtaining the rotation angle of the heliostat at this time; c repeating the step ab once, Obtaining the distance deviation value ei and comparing the set deviation value di; when at least k groups ei>di, wherein lki, calibrating the error of all parameters; otherwise, only the error of the partial parameters is calibrated;

d. The control unit determines the number of rotations of the heliostats according to the number of calibration parameters m, rotating the heliostat at least m/2 times, and calculates the error of the required calibration according to the obtained center position of the spot and the rotation angle of the heliostat.

The image sensor group described in step b acquires the reflected image of the heliostat by fixed or up-and-down movement or left-right movement or rotational movement.

In step c, the deviation value di=nGiLi-1 is set, where GiLi-1 is the ideal moving distance of the center of the reflected image; 0<n1.

In step c, the deviation value di=n LiLi-l is set, where LiLi-1 is the actual moving distance of the center of the reflected image; 0<η 1.

In step c, set the deviation value to a fixed value.

In step d, the number of rotations of the heliostat is at least m/2 times.

In step c, k is a preset value set according to the calibration accuracy.

The error of the partial parameters is a pitch angle error and a pan angle error and/or a heliostat center position error.

In step b, the heliostat rotation angle is obtained by the measured value of the angle sensor or the command of the control unit.

The invention also discloses a heliostat calibration system for a solar power station applying the above calibration method, comprising a receiver for receiving sunlight reflected by a heliostat; a heliostat composed of at least one heliostat Field: mounted around the receiver; image sensor group consisting of at least one image sensor: a calibration source for collecting heliostats; and a control unit for the above calibration method: for processing the image sensor group Image information, and calibrating the parameters of the heliostat tracking the sun while controlling the rotation of the heliostat; the control unit controls the rotation of the heliostat to align the reflected spot of the heliostat with a nominal position, the image sensor The group collects the image of the heliostat reflection spot, and the control unit determines the center position of the heliostat reflection image according to the image information collected by the image sensor group, and compares the center position of the reflection image with the nominal position. A heliostat that is not aligned with the nominal position is determined and the heliostat is calibrated.

The reflected image of the heliostat collected by the image sensor group is a spot for obtaining a contour of the heliostat reflection spot; the image sensor is movably disposed on the heliostat field to make the heliostat The reflected image falls within the acquisition range of the image sensor group.

The image sensor is mounted on a mounting bracket between the receiver and the heliostat field, the image sensor is disposed circumferentially around the receiver and the collection surface of the image sensor faces the A sun mirror is provided that moves up and down along the mounting bracket. The image sensor is movably mounted on a mounting bracket between the receiver and the heliostat field, the image sensor surrounds a circumference of the receiver and the image sensor acquisition surface faces the A receiver arrangement that moves up and down along the mounting bracket.

The image sensor is mounted on a rotating mounting bracket that is rotatable about a support tower of the receiver, the image sensor group is disposed in a vertical direction and its collection surface is disposed facing the heliostat, Rotating around the support frame simultaneously with the rotating mounting bracket.

The image sensor is movably mounted on a rotary mounting bracket, the image sensors are arranged in a horizontal direction and their collection faces are disposed toward the receiver, and the rotary mounting bracket is rotatable about a support tower of the receiver.

The heliostat field is disposed on one side of the receiver, and the image sensor is mounted on a plane mounting bracket between the receiver and the heliostat field, the image sensor group is horizontal or Arranged in a vertical direction that moves up and down or horizontally along the planar mounting bracket.

The reflected image of the heliostat collected by the image sensor group is a spot for obtaining a contour of the heliostat reflection spot; the image sensor is fixedly mounted on the heliostat field, so that the reflected image of the heliostat falls into the image The collection range of the image sensor group.

The image sensor group is mounted on a fixing bracket between the receiver and the heliostat, the image sensor is disposed around a circumference of the receiver, and an acquisition surface of the image sensor faces the A daylight setting, which arranges an array up and down along the center of the receiver.

The image sensor group is fixedly mounted on a fixed mounting bracket between the receiver and the heliostat, the fixed mounting bracket being disposed around a support tower on a lower side of the receiving surface of the receiver.

The heliostat is configured with two rotating shafts, and the heliostat performs a pitch rotation and a panning rotation about the rotating shaft; the double rotating shaft is equipped with an angle sensor for accurately measuring two rotating shafts. The actual angle.

The heliostat is configured with two rotating shafts, and the heliostats respectively perform pitch rotation about two rotating shafts; the double rotating shaft is provided with an angle sensor for accurately measuring the actual rotation of the two rotating shafts angle.

The calibration system also includes a day-of-day tracking sensor for tracking the sun position in real time.

The calibration system also includes a position sensor mounted on the moving track of the image sensor group for determining the position of the receiver and the image sensor.

The calibration source is a solar light source or an artificial light source.

The above technical solution of the present invention has the following advantages over the prior art:

(1) The heliostat calibration method of the present invention determines the number of calibration parameters by judging the error amount of the heliostat, and then performs error calibration, so that when the error is small, only the heliostat is rotated to a smaller number of positions, The data required for the calibration of fewer sets of heliostats is compared to the prior art by manually selecting the number of calibration parameters and then performing error calibration, and both sets of calibration data required for calibration, the calibration of the present invention High efficiency and high calibration accuracy.

(2) The heliostat calibration system of the present invention directly determines the center position of the reflected spot of the heliostat directly through the image sensor group, which aligns the center of the heliostat with the continuous rotation of the heliostat in the prior art. The sensor finally captures the image sensor to the center of the spot. The calibration action of the present invention is fast, the mechanical error is small, and the calibration accuracy is improved.

(3) On the other hand, the image sensor of the present invention is movably disposed in the circumferential direction of the receiver, and the heliostat may be controlled at the control unit to cause the reflection spot of the heliostat to be aligned At the time of the receiver, it is determined that the reflected spot is not aligned with the heliostat of the receiver according to the position of the spot contour obtained by the image sensor. The control unit can only calibrate the heliostats that do not illuminate the receiver on the reflected spot. Quasi. The remaining heliostats on the receiver can continue to operate normally. The solar power plant of the present invention is more efficient than prior art calibration systems that are separate from calibration and power generation.

(4) The calibration light source of the present invention can be selected from sunlight or artificial light source, and can be calibrated by sunlight on a sunny day, and the artificial light source can also be calibrated on a cloudy or nighttime.

DRAWINGS

In order to make the content of the present invention easier to understand, the present invention will be further described in detail below with reference to the accompanying drawings

1 is a trajectory diagram of a heliostat rotation performed when a camera is used to obtain a spot center sample in the prior art;

2 is a schematic view of a heliostat calibration system in Embodiment 1;

Figure 3 is a spot diagram obtained when the image sensor is moved;

4 is a schematic structural view of an image sensor having a dimming device;

Figure 5 is a schematic structural view of an image sensor having a light reducing device and a light blocking device;

Figure 6 is a flow chart of the information flow of the control unit;

Figure 7 is a diagram showing the relationship between the center position of the reflected spot and the nominal position in the embodiment 1;

Figure 8 is a schematic view of a heliostat calibration system of Embodiment 2;

9 is a schematic structural view of an image sensor in which an artificial light source is mounted;

Figure 10 is a schematic view of the heliostat calibration system of Embodiment 3;

Figure 11 is a diagram showing the relationship between the center position of the reflected spot and the nominal position in Embodiment 3;

Figure 12 is a schematic view of a heliostat calibration system of Embodiment 4;

Figure 13 is a schematic illustration of a heliostat calibration system of Embodiment 5;

Figure 14 is a schematic view of a heliostat calibration system of Embodiment 6;

Figure 15 is a plan view of the heliostat calibration system of Embodiment 6;

Figure 16 is a schematic view of the heliostat calibration system of Embodiment 7;

Figure 17 is a schematic illustration of a heliostat calibration system of Embodiment 8;

Figure 18 is a schematic illustration of the heliostat calibration system of the ninth embodiment.

The reference numerals in the figure are indicated as:

1-receiver 2 heliostat 3-image sensor 4, 4'-mounting bracket 5 - dimming device 6 - solar light source 7 - artificial light source 8, 8' - rotating mounting bracket 9 - supporting tower 10, 10' - Planar mounting bracket 11, 11 '- Fixed mounting bracket 12 - Day tracking sensor 13 - Light intensity sensor 14, 14' - Motor 15 - Cooling device 51 - Light reduction disc 52 - Shading device

detailed description

The invention will be further illustrated by the following examples in conjunction with the accompanying drawings.

Example 1

2 shows a heliostat calibration system for a solar power plant, comprising a receiver 1 mounted on a support tower 9, the receiver 1 receiving sunlight reflected by the heliostat 2 to directly generate steam or electricity; The height of the receiver 1 from the ground ensures the setting in the heliostat field The day mirror 2 can be reflected onto the receiver 1.

Also included is a heliostat field mounted around the receiver; the heliostat field includes at least one heliostat 2; the heliostat 2 is configured with two axes of rotation, and the heliostat 2 is wound The rotating shaft performs a pitching rotation and a panning rotation; the double rotating shaft is provided with an angle sensor for accurately measuring an actual pitching angle φ and a panning angle of the two rotating shafts. The heliostat 2 passes The mirror orientation is adjusted to track the moving sun so that the sunlight is continuously reflected onto the receiver 1.

And an image sensor group for capturing a reflected spot of the calibration light source that is incident on the heliostat 2, the image sensor group including at least one image sensor 3. The image acquisition range of the image sensor 3 is greater than the reflection error range of the heliostat field, which captures an image of the heliostat to be calibrated. The calibration light source in this embodiment is a solar light source 6, and the image sensor 3 is a camera mounted on a mounting bracket 4 between the receiver 1 and the heliostat field, and the image sensor 3 surrounds The receiver 1 is disposed circumferentially and moves up and down along the mounting bracket 4.

Since the image sensor group needs to pass between the heliostat 2 and the receiver 1, a large number of heliostat reflection spots are irradiated on the image sensor group, and the energy is extremely high, and the dimming device with a high degree of dimming is required. Therefore, in this embodiment, the image sensor group is provided with a dimming device 5 for reducing the light intensity; the dimming device 5 is a combination of a light reflecting device and a light absorbing device for protecting the image sensor group from strong light. . When the image sensor group moves to the periphery of the receiver 1 and not to the receiver 1, the spot on the image sensor group is greatly reduced, and the excessive reflectance causes the image sensor group to capture the image of the heliostat, so At this time, the degree of dimming needs to be extremely reduced. Therefore, in the present embodiment, it is necessary to provide a device having a variable degree of dimming and a large variation range. As shown in FIG. 4, the dimming device 5 includes a dimming disc 51 which is disposed in front of the image sensor 3 and is equally divided into 6 blocks in the circumferential direction, and the dimming rate of each block is different when the image sensor 3 When moving to the position directly in front of the receiver 1, the light intensity sensor 13 detects that the light intensity is strong, and the control motor 14 rotates the light reduction disk 51 to a block having a high dimming rate when the image sensor 3 is located at the receiver. At the upper or lower position, the light intensity sensor 13 detects that the light intensity is weak, and the control motor 14 rotates the dimming disk 51 to a block having a low dimming rate.

More preferably, a light blocking device 52 coaxial with the dimming disc 51 may be disposed in front of the dimming disc 51, as shown in FIG. The shading device 52 is provided with a light-passing hole to allow all sunlight to pass through, and the other portion shields all sunlight. In operation, the shading device 52 is continuously rotated by the motor 14', asynchronously with the dimming disc 51, and the image sensor completes the acquisition when the light passing hole is aligned with the image sensor. The shading device 52 can reduce the exposure time and further reduce the effect of strong light on the image sensor.

The image sensor group is also provided with a cooling device 15, which is an air-cooled or water-cooled device for preventing damage to the image sensor passing through the receiver due to heat radiation.

The calibration system also includes a day-of-day tracking sensor 12 for tracking the sun position in real time to obtain a solar ray vector.

The calibration system further includes a control unit. As shown in FIG. 6, the control unit receives the heliostat image information acquired by the image sensor group, the position information of the image sensor 3 collected by the position sensor, and the sunlight collected by the tracking sensor 12 Position information, and heliostat 2 rotation angle information acquired by the angle sensor; and controlling the movement of the image sensor 3 and the rotation of the heliostat 2. When the control unit controls the rotation of the heliostat 2 to align the reflected light spot of the heliostat to the receiver, the image sensor group 3 collects an image of the heliostat reflection spot, the control unit Determining a spot center position reflected by the heliostat 2 according to image information collected by the image sensor group, comparing a spot center position with a position of the receiver 1, and determining that the reflected spot is not aligned with the receiver 1. Heliostat 2, and no The heliostat 2 aligned with the receiver 1 is calibrated.

The control unit obtains a spot center position reflected by the heliostat by continuous movement of the image sensor group. When the serial image sensor group is used 30 seconds from the one end of the guide rail to the other end, the two-dimensional map shown in Fig. 3 can be obtained, which reflects the image sensor capable of capturing the reflected spot in the entire time period. According to this figure, the spatial position of the center of the reflected spot, that is, the centroid position of the spot map, can be derived.

The calibration system obtains the rotation angle of the heliostat through an angle sensor mounted on the rotation axis of the heliostat, that is, the pitch angle φ and the pan angle ω information, thereby obtaining the error value of the calibration required for the heliostat. . Wherein, the pitch angle φ of the heliostat is the rotation angle of the heliostat about the axis parallel to the horizontal plane, and the panning angle of the heliostat is the rotation angle of the heliostat about the axis perpendicular to the horizontal plane.

The errors that the heliostats need to calibrate include: pitch angle and pan angle (φ., ω.), the non-perpendicularity η of the two axes of rotation. , the spatial position (x, y, z) of the center of the mirror mirror ο, and the three Euler angles (α 0, β 0, Y o) of the heliostat's own coordinate system relative to the global coordinate system. In the embodiment, more error parameters can also be introduced to improve the calibration accuracy.

Wherein, the pitch angle φ of the heliostat is the rotation angle of the heliostat about the axis parallel to the horizontal plane, and the panning angle ω of the heliostat is the rotation angle of the heliostat about the axis perpendicular to the horizontal plane, the center of the heliostat The position is the position coordinate (x, y, z) of the mirror center of the heliostat, and the non-perpendicular error η of the rotation axis. The actual angle value for the two rotating axes. The Euler angle (α., β., γ.;) is the declination of the heliostat's own coordinate system relative to the three coordinate axes of the global coordinate system.

The calibration method of the heliostat calibration system of the solar power plant comprises the following steps:

a control unit controls the rotation of the heliostat to align the reflected light spot of the heliostat with the nominal position G _{1 ;}

b. The image sensor group is moved once from the upper side of the receiver to the lower side of the receiver to collect the reflected spot of the heliostat, and the control unit determines the center of the spot reflected by the heliostat according to the spot collected by the image sensor group Positioning, and comparing the center position of the spot with the nominal position, determining the distance deviation _ei between the center position of the spot that is not aligned with the receiver and the nominal position and the corresponding heliostat; and obtaining the measured value of the angle sensor Describe the rotation angle of the sun mirror;

c The control unit calculates a set of adjustment angles required to rotate to the nominal position G ₂ according to the center position of the reflected spot at this time and the registered position of the nominal position G ₂ and the center of the mirror surface of the heliostat, and the control unit controls the heliostat to complete Rotate

d. The image sensor group is moved once from the lower side of the receiver to the upper side of the receiver to collect the reflected spot of the heliostat, and the control unit determines the center of the spot reflected by the heliostat according to the spot collected by the image sensor group Position L _{2 ;}

e. The control unit calculates a new distance deviation e ₂ between the spot center position L ₂ and the nominal position G ₂ at this time _; at this time, sets the deviation value d^nG^ , where G ₂ L! is the ideal moving distance of the reflected image center 0<η 1 ;

f. According to e ₂ and d ₂ , when <d ₂ , the heliostat deviation is small at this time, only need to calibrate the pitch angle and the pan angle error, and the center position of the spot and the heliostat rotation Angle information, calculate the error value of the required calibration according to the error calibration formula; when >d ₂ , the heliostat deviation is large at this time, according to the number of calibration errors 9, rotate the heliostat at least 5 times, the image sensor group moves Obtaining a corresponding spot center position and a heliostat rotation angle, and calculating an error value of the required calibration according to an error calibration formula; storing the corrected error value to the control unit.

Wherein, the above error calibration formula is:

3⁄4 ., k― 3⁄4

έ : 3⁄4 one

s ^{3⁄4 ―Sun} , ' Where ω is a panning angle of the heliostat rotating about the axis of rotation;

φ is the pitch angle of the heliostat rotating about the axis of rotation;

S is a unit vector perpendicular to the horizontal plane;

£ is the sun light ray vector;

k is the position coordinate of the spot center;

0 is the coordinate of the center position of the mirror surface of the heliostat.

Wherein, when only the pitch angle error (^ and the pan angle error ω, only the error value of the Euler angle (<1., 0.^.), and the spatial position of the center of the mirror mirror 0 (x, y) The error value of z) and the non-perpendicularity η of the two axes of rotation. The error value calls the stored value in the control unit.

Step c, the center of the spot and the registration vectors _ai heliostat mirror center bisector between the case and the vector b is defined as the sunlight in this case the normal vector of the heliostat mirror _{c. 1;} G ₂ and nominal position registration heliostats The vector at the center of the mirror surface and the bisector between the solar vector b at this time are defined as the mirror normal vector 3⁄4 after the center of the receiver is aligned _{; the} two normal vectors (the angle difference between ^ and 3⁄4 is the fixed date) The angle at which the mirror needs to be rotated.

The nominal positions G1, G2 in step b and step c are control units that control the rotation of the heliostat according to the existing heliostat parameters, attempting to make the heliostat spot reach a predetermined position. The nominal position and the 0 ₂ position may be the same or different. In this embodiment, the nominal position is different from 0 ₂ , as shown in FIG.

According to the calibration accuracy requirement, the set deviation value d ₂ can also be selected as the smaller value of nl^Li or η0 ₂ , where L ₂ I^ is the actual moving distance of the center of the reflected image; G ₂ L! is the ideal moving center of the reflected image Distance; 0<η 1.

Example 2

Fig. 8 shows the heliostat calibration system of the present embodiment, which is different from the calibration system of the first embodiment in that the calibration light source in this embodiment is an artificial light source 7. The artificial light source 7 is disposed on the receiver 1. As another way of implementation, the artificial light source can also be disposed on the movable image sensor 3 as shown in FIG. Thus, even if a large number of heliostats illuminate the reflected spot on the image sensor group, the total energy is much lower than the calibration of the light source. There is no need for a dimming device with a wide range of dimming changes.

Example 3

FIG. 10 is a calibration system in the embodiment, which is basically the same as the calibration system of Embodiment 1, and the difference is:

The image sensor 3 is mounted on a rotary mounting bracket 8 that is rotatable about a support tower 9 of the receiver 1, the image sensor group being disposed in a vertical direction, The rotary mounting bracket 8 is simultaneously rotated about the support tower 9. The control unit obtains a spot center position reflected by the heliostat by rotation of the image sensor group.

The heliostat is configured with two X-axis and Y-axis of rotation axis parallel to the horizontal plane, and the heliostats respectively perform pitch rotation about the two rotation axes; the two rotation axes are respectively equipped with angle sensors, Accurately measure the pitch angle of two rotating axes.

As shown in FIG. 11, the calibration method of the heliostat calibration system includes the following steps:

a control unit controls the rotation of the heliostat to align the reflected light spot of the heliostat with the receiver;

b. The image sensor group rotates once around the support tower 9 to collect a reflection image of the heliostat, and the control unit determines the center position of the spot reflected by the heliostat according to the image acquired by the image sensor group, and Spot center position and nominal position Performing an alignment to determine a distance deviation el between the center position of the spot that is not aligned with the receiver and the nominal position and a corresponding heliostat; and obtaining the date by the measured value of the angle sensor or the command of the control unit Mirror rotation angle; c The control unit calculates a set of adjustment angles required to rotate to the nominal position G ₂ according to the center position of the reflected spot and the registered position of the nominal position G ₂ and the center of the mirror surface of the heliostat, and the control system controls the date The mirror completes the rotation;

d. The image sensor group is rotated again around the support tower 9, collecting the reflected image of the heliostat, the control unit determines the spot center position L ₂ reflected by the heliostat according to the image acquired by the image sensor group _;

e. The control unit calculates a new distance deviation between the spot center position L ₂ and the nominal position G ₂ at this time. At this time, the set deviation value = _η 0 ₂ , where G ₂ L! is the ideal moving distance of the reflected image center; 0<η 1 ;

f. The control unit calculates a set of adjustment angles required to rotate to the nominal position G ₃ according to the reflected spot center position L ₂ and the nominal position G ₃ and the registered position a _{3 of the} center of the heliostat mirror, and the control system controls the setting The sun mirror completes the rotation;

g. The image sensor group is rotated again around the support tower 9 to collect a reflection image of the heliostat, and the control unit determines the spot center position L _{3 of} the heliostat reflection according to the image acquired by the image sensor group _;

h. The control unit calculates a new distance deviation e ₃ between the spot center position L ₃ and the nominal position G ₃ at this time, and at this time, sets the deviation value d ₃ =nG ₃ L ₂ , where G ₃ L ₂ is the ideal movement of the reflected image center Distance; 0<η 1 ;

1. According to e ₂ and d ₂ and e ₃ and d ₂ , when <d ₂ and e ₃ <d ₃ , only the pitch angle, the pan angle error, and the heliostat center position error need to be calibrated. The position of the center of the spot and the rotation angle information of the heliostat can be calculated. When e ₂ >d ₂ or e ₃ >d ₃ , all the errors are calibrated. According to the number of calibration errors 9, the heliostat is rotated at least 5 times, the image The sensor group moves to obtain the corresponding spot center position and the heliostat rotation angle, and calculates the error value of the required update.

In this embodiment, the nominal positions Gi, G ₂ , G _{3 are the} same. The above error calibration formula is:

-, 3⁄4- Φ

Where φΐ is the pitch angle of the heliostat rotating around the X axis;

Φ2 is the pitch angle of the heliostat rotating around the ■ axis ■'

S is a unit vector perpendicular to the horizontal plane;

3⁄4 is the sun light ray vector;

k is the position coordinate of the spot center;

Example 4

12 is a calibration system in the embodiment, which is substantially identical to the calibration system of Embodiment 1, and the difference is that: the heliostat field in this embodiment is located on one side of the receiver 1 on the ground. The image sensor 3 is mounted on a plane mounting bracket 10 between the heliostat field and the receiver 1, and the image sensor group is arranged in a horizontal direction, and moves up and down along the plane mounting bracket 10.

In this embodiment, the moving mode of the image sensor group is intermittent movement at a certain time interval, and the moving mode can obtain a heliostat field reflection spot when the image sensor group stops, and the imaging quality is high. At the same time, the intermittent movement can easily adjust the dimming rate of the dimming device. The calibration method of the heliostat in this embodiment is identical to the calibration method in the first embodiment.

Example 5

13 is a heliostat calibration system of the embodiment, which is substantially identical to the calibration system of Embodiment 1, and the difference is that: the image sensor group is mounted in a fixed manner on the receiver 1 and the predetermined The fixing bracket 11 between the sun mirrors. The range of its acquisition covers the range of reflection errors of the heliostat 2. Thus, the image sensor group can directly capture the reflection profile of the heliostat 2.

The calibration method of the heliostat in this embodiment is basically the same as the calibration method in the first embodiment, except that the image sensor group directly acquires the heliostat image without moving.

Example 6

14 is a heliostat calibration system of the present embodiment, which is substantially identical to the calibration system of Embodiment 1, and the difference is that: the image sensor 3 is mounted on the receiver 1 and the heliostat field. Between the camera on the mounting bracket 4. As shown in FIG. 15, the image sensor components are groups a, b, c, and d4, four sets of image sensors are disposed around the circumference of the receiver 1, and the collection surface of the image sensor 3 faces the The receiver 1 is set, and four sets of image sensors are moved up and down along the mounting bracket 4, respectively. The four sets of sensors a, b, c, and d correspond to heliostats in the four areas of 3, 4, 1, and 2. The heliostats in the four regions are calibrated by the respective movements of the four image sensor groups. When the image sensor moves, the image sensor on the receiver 1 can not collect the spot of the heliostat irradiated onto the receiver 1 due to the occlusion of the receiver 1. The image sensor 3 can only collect and receive no illumination. The heliostat on the device 1 reflects the spot.

The calibration method of the heliostat in the region 1 of the heliostat calibration system includes the following steps:

a control unit controls the rotation of the 1 area heliostat to align the reflected light spot of the heliostat to the receiver;

b. The image sensor c group moves from the upper portion of the receiver to the lower portion of the receiver for the first time to collect the reflected light spot of the heliostat, and the control unit determines the reflection of the heliostat according to the spot collected by the image sensor c group. Positioning the center of the spot, and comparing the center position of the spot with the nominal position, determining the center position of the spot that is not aligned with the receiver and the nominal position deviation _ei and the corresponding heliostat; and passing the measured value or control of the angle sensor The command of the unit obtains the rotation angle of the heliostat; c The control unit calculates a group required to rotate to the nominal position G ₂ according to the center position of the reflected image at this time and the registered position of the nominal position G ₂ and the center of the mirror surface of the heliostat Angle, the control system controls the heliostat to complete the rotation;

d. The image sensor c group is moved once from the lower side of the receiver to the upper side of the receiver, and the reflected spot of the 1 area heliostat is acquired, and the control unit determines the heliostat reflection according to the spot collected by the image sensor group. The spot center position L _{2 ;}

e. The control unit calculates a new distance deviation e2 between the spot center position L ₂ and the nominal position G ₂ at this time, at this time, the set deviation value d ₂ is a fixed set value of 0.2 m;

f. According to e ₂ and d ₂ and e ₃ and d ₂ , when <d ₂ , the heliostat deviation at this time is small, only the center position error of the heliostat is required, and the center position of the spot that has been obtained is The heliostat rotation angle information can be calculated and obtained; when e ₂ >d ₂ , the heliostat deviation is large at this time, according to the number of calibration errors 9, the heliostat is rotated 6 times, the image sensor group moves, and the corresponding The position of the center of the spot and the angle of rotation of the heliostat, calculate the error value of the desired update.

The heliostats in the 2, 3, and 4 regions are calibrated by the above methods. The above error calibration formula is:

Where ω is a panning angle of the heliostat rotating about the axis of rotation;

φ is the pitch angle of the heliostat rotating about the axis of rotation;

S is a unit vector perpendicular to the horizontal plane;

£ is the sun light ray vector;

k is the position coordinate of the spot center;

In step a, when the spot collected by the image sensor 3 is a partial spot, the control unit first calculates the area value A according to the partial spot profile that has been obtained; calculates the corresponding heliostat, and then according to the registered position of the heliostat Calculate the area AO value of the reflected spot, and obtain the remaining spot area value as A0-A, and fill the remaining spot contour by a rectangle. Finally, the geometric centroid of the partial spot contour and the complementary area is calculated, and the control unit controls the heliostat rotation to rotate the heliostat to the entire spot where it can be captured by the image sensor group.

In order to improve the calibration accuracy, more steps ab can be repeated to obtain more sets of spot center position and heliostat pitch angle and pan angle value. According to multiple sets of data, the error value of the required calibration is calculated by the error calibration formula. .

Example 7

16 is a heliostat calibration system of the present embodiment, which is different from the calibration system of Embodiment 1 in that: an image sensor group is fixedly mounted between the receiver 1 and the heliostat The fixed mounting bracket 1 is disposed around the support tower 9 on the lower side of the receiving surface of the receiver 1. In this embodiment, the image sensors are evenly arranged in the longitudinal direction as well as in the lateral direction.

Example 8

17 is a heliostat calibration system in the embodiment, which is substantially identical to the calibration system of the first embodiment, and the difference is that the image sensor 3 is movably mounted on the rotary mounting bracket 8'. The image sensor 3 is arranged in the horizontal direction and its collecting face is arranged facing the receiver 1, and the rotary mounting bracket 8' is rotatable around the support tower 9 of the receiver. The control unit obtains a spot center position reflected by the heliostat by up and down movement and rotation of the image sensor group.

The calibration method of the heliostat in this embodiment is identical to the calibration method in the third embodiment.

Example 9

FIG. 18 is a calibration system in the embodiment, which is substantially identical to the calibration system of Embodiment 1. The difference is that: the image sensor group is three groups, and the mounting bracket 4 is mounted on the heliostat field. The upper two sets of image sensors move up and down along the mounting bracket 4. Also included is a set of image sensors mounted on a planar mounting bracket 10, the planar mounting bracket 10 being located on a support tower 9 of the receiver 1, the image sensors being arranged in a horizontal direction with the planar mounting bracket 10 move up and down. In this embodiment, three sets of image sensors can calibrate image sensors in different regions of the heliostat field. The calibration method of the heliostat in this embodiment is identical to the calibration method in the first embodiment. In this embodiment, the moving mode of the image sensor group is intermittent movement at a certain time interval, and the moving mode can obtain a heliostat field reflection spot when the image sensor group stops, and the imaging quality is high. At the same time, the intermittent movement can easily adjust the dimming rate of the dimming device.

It is apparent that the above-described embodiments are merely illustrative of the examples, and are not intended to limit the embodiments. Other variations or modifications of the various forms may be made by those skilled in the art in light of the above description. Obvious changes or variations resulting therefrom are still within the scope of the invention.

Claims

Claim

A calibration method for a heliostat calibration system for a solar power plant, comprising: the following steps:

a control unit controls the rotation of the heliostat to align the reflected image of the heliostat with the nominal position G _{1 ;}

b. The image sensor group collects the reflected image of the heliostat, and the control unit determines the center position L of the reflected image of the heliostat according to the image acquired by the image sensor group, and the center position of the reflected image is Comparing the nominal position 3⁄4, determining a distance deviation between the center position 1^ of the reflected image and the nominal position 3⁄4 and the corresponding heliostat; and simultaneously obtaining the rotation angle of the heliostat at this time;

c Repeat 1 step a-b to get the distance deviation value compared with the set deviation value 4; when at least 1^ group >4, where Kk i, calibrate the error of all parameters; otherwise, only need to calibrate the error of some parameters;

d. The control unit determines the number of rotations of the heliostat according to the number of calibration parameters m, and calculates the error of the required calibration according to the obtained spot center position and the rotation angle of the heliostat.

2. A heliostat calibration method for a solar power plant according to claim 1, wherein:

3. The method of calibrating a heliostat of a solar power plant according to claim 1 or 2, characterized in that:

In step c, the offset value is set to 4=η3⁄4Ι^, where GLw is the ideal moving distance of the center of the reflected image; 0<η 1.

The method for calibrating a heliostat of a solar power plant according to claim 1 or 2, characterized in that:

In step c, the deviation value dfn LiLM is set, where I^LM is the actual moving distance of the center of the reflected image; 0<η1.

The method for calibrating a heliostat of a solar power station according to claim 1 or 2, characterized in that:

In step c, set the deviation value 4 to a fixed value.

6. The heliostat calibration method for a solar power plant according to any one of claims 1-5, characterized in that:

In step d, the number of rotations of the heliostat is at least m/2 times.

7. The heliostat calibration method for a solar power plant according to any one of claims 1-6, characterized in that:

In step c, k is a preset value set according to the calibration accuracy.

The method for calibrating heliostats of a solar power station according to any one of claims 1 to 7, wherein:

9. A heliostat calibration method for a solar power plant according to any of claims 1-8, characterized in that:

10. A heliostat calibration system for a solar power plant using the calibration method of any of claims 1-9, characterized in that it comprises a receiver (1) for receiving Sunlight reflected by the sun mirror;

a heliostat field consisting of at least one heliostat (2): mounted around the receiver;

An image sensor group consisting of at least one image sensor (3): a calibration light source reflection image for collecting heliostats; and a control unit using the calibration method according to any one of claims 1-9: for processing an image sensor group Image information, and calibrating the parameters of the sun's heliostat while controlling the heliostat rotation;

The control unit controls the rotation of the heliostat (2) to align the reflected spot of the heliostat (2) with a nominal position, and the image sensor group (3) collects an image of the reflected spot of the heliostat The control unit determines the location according to the image information collected by the image sensor group Describe the center position of the reflected image (2), compare the center position of the reflected image with the nominal position, determine the heliostat (2) that is not aligned with the nominal position, and determine the heliostat ( 2) Perform calibration.