WO2013056507A1

WO2013056507A1 - Heliostat angle deviation detection method for solar tower thermal power system

Info

Publication number: WO2013056507A1
Application number: PCT/CN2012/001049
Authority: WO
Inventors: 邵文远
Original assignee: Shao Wenyuan
Priority date: 2011-10-18
Filing date: 2012-08-06
Publication date: 2013-04-25
Also published as: CN102506810B; CN102506810A

Abstract

A heliostat angle deviation detection method for a solar tower thermal power system. The power system comprises a heat absorber (H) fixed on a tower (T), and several heliostats (M). The power system is provided with an imaging unit. The imaging unit comprises a lens (E), a camera or a video camera connected to the lens (E), and a computer connected to the camera or the video camera. The lens (E) is arranged at the center of the heat absorber (H) or along the periphery thereof. Steps for determining whether the positions of the heliostat mirrors are correct according to an image taken by the imaging unit are: (1) establishing coordinates of the center (Q_K) of each heliostat (M) in the heliostat field; (2) when the system operates, searching an obtained image for coordinates of the center (Q_K') of a virtual image of the sun or the virtual image of the sun; (3) determining whether the angle of each heliostat (M) is correct by determining the overlap ratio between the center (Q_K') of the virtual image of the sun and the center (Q_K) of the heliostat mirror or whether a virtual image of the sun exists. The advantages thereof are that the efficiency, degree of automation, and accuracy of the detection are improved.

Description

Heliostat angle deviation detection method for tower solar thermal power generation system

The present invention relates to a solar thermal power generation system, and more particularly to a heliostat angular deviation detection method for a tower solar thermal power generation system.

Background technique

At present, solar thermal power generation mainly includes two types of trough type and tower type, and the trough type structure is relatively simple, but the temperature of the heat absorber can generally only reach 200 ° C or more, and the power generation efficiency is low. The tower structure is relatively complicated, but the temperature of the heat absorber can generally reach 500 ° C or more, and the power generation efficiency is high.

The principle of tower solar thermal power generation technology is to use a heliostat to reflect sunlight to a heat sink located on a high tower to realize large-capacity power generation. The power station system includes a heliostat field, a heat sink, a heat storage device, and a power generating device.

As the sun rises and falls, every heliostat in the heliostat field must also move from east to west, and from bottom to top, and then from top to bottom, to ensure that the reflection of sunlight on each side of the heliostat is concentrated. On the tower's heat sink. According to the relative position, time, location, etc. of each heliostat and heat sink, the azimuth and elevation angle of each heliostat at any time can be calculated, but due to atmospheric refraction, mechanical error, thermal expansion and contraction, Materials such as aging will cause deviations in reflection and affect power generation efficiency. Design the fixed angle field deviation measurement and correction system, which can be used as the negative feedback parameter of the control system. Adjust the azimuth and elevation angle of each surface heliostat in time, so that the reflection of sunlight from the heliostat is always aligned with the heat absorber. Power generation efficiency.

There is a foreign calibration system that uses a whiteboard under the heat sink to reflect the sunlight of the heliostat that needs to be corrected to the whiteboard. If the calculated azimuth and elevation angle are accurate, the spot on the whiteboard is just at the center of the whiteboard. Position; if not in the center position, you need to manually adjust to the center position, measured The error between the theoretical and actual values of azimuth and elevation. Finally, move up a certain angle (the angle of the heliostats on each side is not exactly the same) and align the heat sink. There are four disadvantages of this method: one is that it must be manually adjusted once there is an error; the second is that it will also produce an error when moving up; the third is that it can only adjust one heliostat at a time; the fourth is that it cannot contribute heat to the suction during calibration. Heater.

Summary of the invention

The object of the present invention is to overcome the above-mentioned deficiencies of the prior art, and provide a detection method for forming a corresponding spot by automatically correcting whether each heliostat in the mirror field can reflect sunlight to the heat absorber without manual intervention. The plan is as follows:

One of the heliostat angle deviation detecting methods of the tower solar thermal power generation system, the tower solar thermal power generation system includes a heat absorber fixed to the tower and a plurality of surface fixed mirrors rotatable at corresponding fixed positions The plurality of surface heliostats are arranged in a set manner to form a mirror field, and each of the heliostats reflects sunlight to the heat absorber at the correct position, wherein the tower solar thermal power generation system is Providing a first imaging unit, the first imaging unit comprising a first lens E and a camera or camera connected to the first lens and a computer connected to the camera or the camera, the first lens being disposed on the heat sink The central region is at a constant value L _k from the center of the mirror surface of the k-th surface of the mirror field to form a first center line EQ _k . The axis of the heliostat rotating in the horizontal plane and the vertical plane passes through the mirror center Qk, and the mirror width of the mirror center Qk is D _k and the height is H _k , and the first imaging unit can photograph the corresponding heat sink The corresponding image of the entire mirror field, through which the steps of determining the mirror position of the heliostat are correct are as follows:

1) Establish mirror center coordinates

Adjusting all the heliostats in the mirror field so that the mirror surface is perpendicular to the first center line EQ _k , and then photographing the corresponding mirror field with the first imaging unit to form an initial image of the mirror field, through the initial image Establishing the pixel coordinate value of the center of each heliostat as the center coordinate of the heliostat, and calculating the mirror surface The amount of pixels N _Dk and Ν contained in the linear direction of the width D _k and the height H _k _;

2) Find the coordinates of the sun virtual image center when the system works

When the tower solar thermal power generation system is in operation, the first imaging unit performs a shooting on the corresponding mirror field at each set time interval to form a current image of the mirror field, and the computer finds each side of the current image. The pixel coordinate value of the sun virtual image center Q corresponding to the heliostat, as the central coordinate of the solar virtual image, and calculate the sun virtual image center Q of each heliostat, to the second center line EQ of the lens ,, and the said The angle formed by the angle of a central connection EQ on the horizontal plane is Θ and the elevation angle of the vertical plane is Φ, and the center of the solar virtual image of the k-th surface heliostat is (V, to the second center line E8 of the lens E) _k 'and the line connecting the centers of the first _{_k} EQ _k 9 _k formed azimuth and elevation _(I);

3) Determine whether the mirror angle of the heliostat is correct

The center coordinates of the solar virtual image of each of the heliostats and the coordinates of the center of the corresponding heliostat are compared at the time interval:

If the difference between the two centers is within the set range, the mirror angle of the fixed heliostat is correct, and no adjustment is needed. If the setting range is exceeded, the mirror angle of the corresponding heliostat is incorrect and needs to be adjusted.

In the tower solar thermal power generation system, the heliostat angle deviation detecting method is the second, the tower solar thermal power generation system includes a heat absorber fixed to the tower and a plurality of surface fixed mirrors that can rotate at corresponding fixed positions. The plurality of heliostats are arranged in a set manner to form a heliostat field, and each of the heliostats reflects sunlight to the heat absorber at the correct position, wherein the tower solar thermal power generation a first imaging unit and a second imaging unit are disposed in the system, the first imaging unit including a first lens and a camera or camera connected to the first lens and a computer connected to the camera or the camera; the second imaging The unit includes a plurality of second lenses, a number of cameras or cameras coupled to the corresponding second lens, and a computer coupled to the camera or camera. The first lens is disposed in the central region of the heat sink, and the distance from the center of the k-th heliostat in the mirror field is a constant value L _k , and the center line 6 is formed (3⁄4 and heliostat) The angle of the plane, the angle is decomposed into the azimuth angle on the horizontal plane is e _k and the elevation angle on the vertical plane is (b _k , the axis of the heliostat rotating in the horizontal plane and the vertical plane passes through the mirror center Q _k , The first imaging unit can capture an image of the entire mirror field; the plurality of second lenses are disposed on the periphery of the heat absorber, and the distance between the adjacent two second lenses is smaller than the width or height of the minimum reflected spot. The steps of determining whether the mirror position of the heliostat is correct by the images taken by the first and second imaging units are as follows:

1) Establish mirror center coordinates

Adjusting all the heliostats in the mirror field so that the mirror surface is perpendicular to the first center line EQ _k , respectively, using the first and second imaging units respectively to shoot the corresponding mirror field, forming an initial image corresponding to the mirror field, the initial image to correspond to the first, respectively, on each side of the center pixel coordinate values of the heliostat second imaging unit as center coordinates of the heliostat, and calculates the linear mirror width direction and a height H _k D _k of The amount of pixels N _Dk and Ν included _;

2) Find the sun image when the system works

When the tower solar thermal power generation system is in operation, the second imaging unit performs a shooting on the mirror field at each set time interval to form a current image of the mirror field, and the computer searches for each side of the image. Whether there is a sun image in the heliostat;

3) Determine whether the mirror angle of the heliostat is correct

At the time interval, it is determined whether there is a solar virtual image in each of the heliostats in the current image. If there is no solar virtual image, the mirror angle of all the heliostats in the mirror field is correct, and the heliostat does not need to be adjusted, if there is a sun virtual image, corresponding The heliostat needs to be adjusted, and the azimuth angle 水平 on the horizontal plane and the elevation angle Φ on the vertical plane of the lens E to the sun-definition center Q' line EQ' of the corresponding heliostat and the first center line EQ are calculated. . The center of the solar virtual image of the _k- th surface heliostat is Q _k ', and the second center line EQ _{k of the} lens E forms an azimuth angle of 6 _k and an elevation angle (i) _k with the first center line EQk.

The k-th surface heliostat has a horizontal rotation angle β _1{{ and a vertical rotation angle δ _k after the mirror surface The center Qk' of the image coincides with the center Q _k of the mirror, and the pitch of the center of the heliostat Q _k before the rotation to the center of the virtual image Qk' in the horizontal direction is n _Dk pixels, and the pitch in the vertical direction is η The number of pixels, the k-th surface heliostat horizontal rotation angle P _k , the vertical rotation angle S _k , the distance L _k from the first lens to the k-th surface of the heliostat, and the azimuth angle of the k-th surface heliostat 8 _k The width of the k-th surface heliostat, the height H _k of the k-th surface heliostat, the pixel amount N _Dk included in the linear direction of the k-th surface heliostat width D _k , and the k-th surface heliostat height H _k The amount of pixels 线性 in the linear direction, the center of the heliostat Q _k to the center of the virtual image Q _k 'the amount of pixels in the horizontal direction n _Dk , the distance from the center of the heliostat Q _k to the center of the virtual image Q _k ' in the vertical direction The amount of pixels has the following relationship:

6 _k =D _k X n _Dk / N _Dk / L _k or * k ⁼ nHk NHk L _k

e _k = e _k / 2 or s _k = Φ„/ 2

A further design of the heliostat angle deviation detecting method of the tower solar thermal power generation system is that the first lens is disposed at a fixed position in a central region of the heat absorber or U cells disposed in a central region of the heat absorber In the positioning position, the mirror field is divided into corresponding U regions, so that the first lens has a mirror field corresponding to each of the positioning positions.

The heliostat angle deviation detecting method of the tower solar thermal power generation system is further designed such that the heliostat is a plane mirror or a parabolic mirror.

The first imaging unit in the above-described tower solar thermal power generation system can be moved, and the correction method of the movement error is that at least three are not in a straight line at the position of the amorphous heliostat in the mirror field. a controllable laser emitter or a high-intensity illumination device, the range of the light beam emitted by the laser emitter or the high-intensity illumination device covering the first imaging unit and the second imaging unit, and the controllable laser emitter or high-brightness illumination The illumination frequency of the device corresponds to the time interval, and the steps of correcting the movement error of the first imaging unit are as follows:

1) Establish the reference coordinates of the heliostat pixels A mirror correction image including a controllable laser emitter or a high-intensity illumination device is captured by the first imaging unit and the second imaging unit, and the pixel coordinate value of the controllable laser emitter or the high-intensity illumination device is determined by the correction image, The pixel coordinate value is used as a reference to establish a standard coordinate system, and the reference pixel coordinates corresponding to the standard coordinate system of each certain 曰 mirror in the mirror field are determined;

2) Determine the pixel coordinates of the current heliostat

Selecting a time point corresponding to the time interval, capturing a current mirror image with the first imaging unit, calculating a current mirror image with respect to a current heliostat pixel position of the standard coordinate system, and determining a corresponding heliostat Current pixel coordinates;

3) Discriminant error

The current pixel coordinates of the heliostat are compared with the corresponding reference pixel coordinates. If the two-pixel coordinate error is within the set range, the corresponding heliostat does not need to be adjusted. If the setting range is exceeded, the corresponding heliostat needs to be adjusted.

The invention provides an imaging unit mainly composed of a lens, a camera or a camera and a computer in a solar thermal power generation system, and analyzes and calculates the image according to an image taken by a lens, a camera or a camera, and determines a position of the sun virtual image from the solar thermal power generation system. To detect if the mirror of the heliostat reflects sunlight to the heat sink. In the present invention, the lens is placed in a central region of the heat absorber, and the lens has a suitable wide angle to image the entire mirror field, thus constituting the first technical solution of the present invention; In the lens of the center area, several lenses are placed around the heat absorber. The first lens located in the central area of the heat sink is generally used to adjust the initial position of the heliostat in the mirror field; the second lens located around the heat absorber is generally used for the position of the heliostat when the solar thermal power system is working. The monitoring thus constitutes the second technical solution of the present invention. The first technical solution is a basic application solution; the second technical solution is an extended application solution.

In the heliostat of the present invention, the horizontal axes of the horizontal and vertical planes pass through the mirror center Q. Referring to Fig. 1, the heliostat M can bypass the Z axis of the mirror center point Q as a horizontal plane (QXQY plane in the figure). On The rotation can also bypass the BB axis of the mirror center point Q (when the heliostat rotates around the Z axis to a certain angle, and the BB axis is parallel to the X axis) to make a vertical plane (QYQZ plane in the figure). Therefore, no matter how the heliostat rotates its mirror center Q, the distance L between the lens and the mirror center Q is constant. The rotation of the heliostat mirror as it moves with the sun is produced by rotation in both horizontal and vertical directions. The angle between the line EQ of the first lens E and the center Q of the heliostat mirror Q and the line EQ' of the virtual image Q' of the sun is decomposed into an azimuth angle 水平 in the horizontal direction and an elevation angle Φ in the vertical direction. The invention cleverly utilizes the principles of optics and geometry to make the adjustment of the mirror angle simple and precise. As long as the horizontal direction rotates β = Θ / 2 and the vertical direction rotates δ = φ / 2, the solar virtual image can coincide with the center position of the heliostat crucible. . In the following, the water level, that is, the QXQY surface in Fig. 1 will be described as an example (the principle of the vertical plane is the same).

Referring to Figure 2, SS ₂ is the two positions in the sun movement, moving from 8 ₁ to S ₂ .

S ₂ 'is the virtual image of Si, S ₂ in heliostat M, M' is the extension of heliostat, A, A ₂ is the corresponding imaging of the sun in the heliostat at 8 ₁ and S ₂ positions. The intersection of the position and the mirror. When the first lens E and the heliostat M do not move, the sun moves from the time to the S ₂ : the first lens E observes that the virtual image of the sun moves from the movement to the S ₂ ', which is reflected on the heliostat from the movement of the ^ to the A ₂ , its length is d. The distance between the first lens E and the mirror center Q of the k-th surface heliostat M is L _k , the angle between the EQ and the horizontal direction of the mirror surface is Ω, and the distances from the lens Ε to Α, and the 八₂ are substantially the same (the The difference is negligible), basically equivalent to L, and the arc length corresponding to the azimuth angle is basically equal to the corresponding chord length, then:

d X sin Q =L X θ ( 1 )

If the heliostat and Α _{2 are} set at both ends of the width of the heliostat (the width D of the heliostat is the length of the mirror side perpendicular to the axis of rotation of the heliostat), the heliostat can be passed through the imaging unit. Seeing the azimuth of the sun's maximum change, 0 max, there are:

D X sin Q = L X Θ max (2)

Therefore, if the virtual image of the sun observed by the imaging unit is at the center of the heliostat, the change in the azimuth of the sun In the range of ±0.5 Θ _max radians, the imaging unit can see the virtual image of the sun through the heliostat, and can accurately determine the amount of change in the azimuth.

When the first lens E does not move and the heliostat rotates at an angle P, refer to FIG. 3. In the figure, E is the lens of the imaging unit, and M ₁ is the initial position of the heliostat (still assumed to be the plane mirror), and M ₂ is The heliostat rotates at a position where P is the center of rotation, and SS ₂ is the parallel light when the sun does not move but is imaged on E by heliostat movement. S, , and S ₂ ' are S ₂ in the day Mirror] ^ ₁ and ] ^ ₂ position of the virtual image, A „ 八₂ is the position of the corresponding virtual image formed on the mirror surface of the sun at the position of S ₂ . When the first lens E does not move, heliostat from] ^到]^ ₂ Rotate, the first lens E observes that the virtual image of the sun moves from Si ' to S ₂ ', which is reflected from the movement of ^ to A ₂ on the heliostat. And S ₂ A ₂ is a parallel line, quadrilateral CA ₂ QA, the inner angle sum is 2π, then there are:

(π-2α ) +Ζγ+Ζ (π- β ) +Ζα = 2π

γ = β + α

The inner angle sum of the triangle EA ₂ C is π, then:

θ + (π-2γ ) +2α = _π

Then you can get: θ = 2β (3) From (1), (2) can be obtained:

dX sinQ = LX23 (4) DX sinQ= L X2Praax (5) In this way, the imaging unit is rotated when the heliostat rotation angle is P while the imaging unit imaging unit and the sun are stationary (instantaneous) and the heliostat is rotated. The change in the virtual image angle of the sun observed by the imaging unit is Θ, and the relationship between the two is θ = 2β. If the solar virtual image in the corresponding heliostat can be observed from the imaging of the first lens, when the azimuth of the sun moves to Θ, the heliostat rotates correspondingly Θ /2, which ensures that the mirror of the fixed 面对 mirror faces the suction The same position of the heat, that is, the heliostat can reflect the sun's rays, on the heat sink A corresponding spot is formed.

As can be seen from Fig. 2, it is assumed that A1 is the center of rotation of the heliostat, i.e., the position of A1 does not move in the imaging unit with the rotation of the heliostat. When the position of the sun is 3 ₂ , the virtual image is S ₂ ', and the difference between the horizontal angle of the sun and the exact angle can be calculated by formula (1):

θ= d XsinQ /L (6) d X sin Ω is the projection of the heliostat M on the vertical plane of the EQ, that is, the number of pixels of the imaging unit and the number of pixels of the heliostat width (horizontal direction) Proportion; as shown in Figure 4. It can be seen that d = A!A ₂ , d X sinQ = A!A ₂ X sinQ =Α ₁ Α ₂ ', when the connection between the imaging unit 定 and the heliostat is perpendicular to the Μ, the width of the heliostat D is horizontal N _D pixels in the imaging unit, as shown in Fig. 4a; when the heliostat horizontal deflection angle is Ω, the heliostat becomes M' in the imaging unit and the width is DX sinQ, as shown in Fig. 4b. A!A ₂ is ^ ΑΛ in the imaged image corresponding to the number of pixels n _D , d X sinQ : n _D = D _: N _D , which gives:

d X sinQ =DX n _D /N _D (7) Bring into equation (6), get

Θ = D Xn _D / N _D / L (8) D, N _D , L are constants, n _D is the number of horizontal pixels from the center of the virtual image of the sun to the center of the heliostat, which can be accurately determined by the above formula Calculate the deviation angle in the horizontal direction. When the maximum deviation value is reached, the heliostat horizontal rotation β=θ/2 angle is required, and Θ can be set.

Similarly, the elevation deviation formula in the vertical direction:

Φ = H Xn _H / N _H / L (9) H, N _H , L are constants, and ii _H is the number of vertical pixels from the center of the virtual image of the sun to the center of the heliostat. With the above formula, the deviation angle in the vertical direction can be accurately calculated. When Φ reaches the maximum deviation value, the heliostat vertical rotation δ = φ 12 angle is required, and Φ can be set. Therefore, if the solar virtual image in the corresponding heliostat is not observed from the first lens placed in the central region of the heat absorber, the angle β or δ of the heliostat rotation is less than the set range, so that the heliostat is on the heliostat. The light must not reflect the sunlight onto the first lens, and there is no reflection of sunlight onto the heat sink. If the solar virtual image in the corresponding heliostat is not observed from the second lens placed around the periphery of the heat absorber, the heliostat must reflect the sunlight onto the first lens, and the reflected sunlight of the surface of the heliostat just deviates. With the heat sink, the corresponding second lens can observe the virtual image of the sun. At this time, the computer can determine which side of the heliostat is deviated, the direction of deviation, the angle, etc., and can notify the transmission mechanism to correct. Since the second lens is mounted on the periphery of the heat absorber, it does not affect the heat absorption of the heat sink, and the temperature around the heat absorber is lower than the center, and the cooling system and life are better guaranteed.

According to the above principle, the first imaging unit provided by the present invention can obtain the following beneficial effects: as long as the azimuth and elevation angles are within a certain error range, the analysis of the imaging in the first lens can be automatically corrected; in engineering techniques and processes When allowed, all the heliostats in the mirror field can be corrected at the same time, and the degree of automation is high, which improves the accuracy of the hemispherical deviation angle detection and the efficiency of the detection work. In addition, deviations caused by lens movement can be eliminated by a controllable laser emitter or a high-intensity illumination device. Setting the second imaging unit can reduce the use of the first imaging unit, increase the efficiency of receiving light, and increase the range in which the deflection angle is detected.

DRAWINGS

Figure 1 is a schematic diagram of the projection of the angle between the first lens and the center of the heliostat and the center of the solar virtual image on the horizontal and vertical coordinate planes.

Figure 2 is a schematic diagram of the imaging principle when the sun moves the heliostat without rotation.

Figure 3 is a schematic diagram of the imaging principle when the sun does not move the heliostat.

4 is a schematic view showing the principle of imaging of a solar virtual image position in the center position of the heliostat in FIG. Fig. 5 is a schematic view showing the structure of an embodiment of the first imaging unit of the present invention. Fig. 6 is a structural schematic view showing a position where a first lens or a plurality of first lenses are rotatable.

Fig. 7 is an image of a mirror field taken as indicated by the reference coordinates of the first imaging unit establishing the heliostat pixels. Figure 8 is a schematic diagram of an image taken by the first imaging unit when all of the heliostats in the mirror field are in the correct position.

Fig. 9 is a view showing a case where the heliostat mirror is in an incorrect position in the image taken by the first imaging unit.

Fig. 10 is a view showing an image taken corresponding to the second imaging of the mirror field condition shown in Fig. 8.

Figure 11 is a schematic view showing the structure of an embodiment of the present invention having both the first and second image forming units.

detailed description

The invention and its advantages are further described below in conjunction with the drawings and embodiments. Still taking the horizontal azimuth angle as an example, the vertical elevation angle principle is the same.

Example 1

Referring to Figure 5, the tower solar thermal power generation system includes a tower 1 \ a heat sink H and a heliostat ^. The first imaging unit E is fixed on the central region of the heat sink H on the tower T, and a plurality of surface heliostats are arranged under the tower in a set manner to form a mirror field (it is possible to fix a plurality of heat absorbers 11 around the tower T, the mirror field The sub-rings are arranged around the lower part of the tower, and each of the heat absorbers corresponds to a part of the mirror field. In this embodiment, a heat absorber and a corresponding mirror field are taken as an example. The mirror of the k-th surface heliostat M _k faces the heat absorber H, and forms a spot on the heat sink by reflecting the light of the sun. The surface heliostat M _k is fixed in position and can be rotated horizontally and vertically. The axis Z of the horizontal rotation and the axis X of the vertical rotation pass through the mirror center Q _k . The mirror width Q _k through the mirror center is D _k , the height is H _k , and k is a natural number of 1, 2, 3 to m. When the position of the sun changes, the mirror rotates at regular intervals to follow the change in the position of the sun. Providing a first imaging unit in the above-described tower solar thermal power generation system, the imaging unit mainly comprising a first lens E and a camera or camera connected to the first lens and the camera or the camera Connected to the computer, the first lens E is disposed in a central region corresponding to the heat absorber H, and the distance from the mirror surface center Q _k of the k-th surface of the mirror field is a fixed value L _k , and the center line EQ is formed. The angle between _k and the plane of the heliostat is decomposed into an azimuth angle e _k on the horizontal plane and ci) _k on the vertical plane. If the mirror field is too large relative to the resolution of the first lens E, a rotatable first lens or a plurality of first lenses may be employed. The first lens is placed on a U-position that is centered around the center of the heat absorber, and the mirror field is divided into corresponding U regions, each of which corresponds to a positioning position of the first lens on the circumference. . For example as shown in FIG. 6, the first lens in a circumferential E C _H 0 _H of the center of the heat sink 4 can be positioned with a location corresponding to the mirror field is divided into four regions, each region on the circumference of the first lens A positioning position corresponds. The first lens should have sufficient resolution, wide angle (can observe the entire mirror field), telescopic lens (similar to the furnace flame probe), adjustable receiving light intensity, high temperature resistance and high brightness, and can image the entire mirror field, ie All heliostats in the mirror field can be observed in lens E. The steps to determine if the mirror position of the heliostat is correct by this image are as follows:

First, the first imaging unit is used to shoot the mirror field. All the heliostats in the mirror field are perpendicular to EQ _k to form the initial image of the mirror field. Referring to FIG. 7, the pixel coordinates of the center of each heliostat are established by the initial image. The value is taken as the center coordinate of the heliostat, and the pixel amount N _Dk and ϊ1⁄2 included in the linear direction of the mirror center through the mirror width D _k and the height H _k are calculated, and the pixel length and the pixel unit length are obtained, thereby obtaining the width D. The corresponding value of _k and height 3⁄4 and the amount of pixels N _Dk and Ν. Perform the above initial shooting to select the morning sun or sunset or the non-direct sunlight that shields the sun from the clouds. Avoid adjusting the mirror field to reflect sunlight on the first imaging unit. When the tower solar thermal power generation system is working, the first imaging unit performs a shooting on the mirror field at each set time interval to form an image as shown in FIG. 8. The computer analyzes the captured image as follows: The surface of the heliostat with a virtual image of the sun (with strong reflections, which can be displayed on the photo) is calculated. If the center Q _k ' of the virtual image coincides with the center Q _{k of the} heliostat, then the heliostat can be determined. Azimuth and elevation are accurate; if there is a heliostat with its virtual image The center of the center and the heliostat must have a certain number of gaps, as shown in Figure 9, at the k34 position of the heliostat, according to the formula:

θ ₃ 4 = D34 X n _D34 / N _D3 4 L ₃₄ and Φ 34 = Η ₃ 4 Xn _H34 / N _H3 4/ L ₃ 4 β 34 = θ ₃₄ / 2 and δ ₃₄ = φ ₃₄ / 2

The k34 mirror requires azimuth adjustment β ₃₄ and elevation angle adjustment δ ₃₄ . Example 2

In this embodiment, in view of the fact that the first lens in the above embodiment is in the central region of the heat absorber, the heat absorption effect is affected, and the temperature is high, which affects the life of the lens. Therefore, in this embodiment, a plurality of second lenses, second cameras or a plurality of second cameras are further provided on the basis of the above embodiments. A plurality of second lenses F are distributed around the periphery of the heat absorber to form a "fence" shape. Referring to Figure 11, the distance between the two second lenses F is smaller than the width or height of the minimum reflected spot. Therefore, the imaging unit of the present embodiment actually includes two portions, a first imaging unit and a second imaging unit composed of a plurality of second lenses, a second camera or a plurality of second cameras and a computer.

Initially, the first imaging unit and the second imaging unit respectively perform corresponding mirror image capturing, respectively forming corresponding initial images of the mirror field, and each of the heliostats corresponding to the first and second imaging units is respectively established by the initial image. The center pixel coordinate value, as the center coordinate of the heliostat, obtains the mirror field center coordinate set. And the pixel amounts N _D and N _H included in the linear direction of the mirror width D and the height Η are calculated. Then, the corresponding mirror field is adjusted by the first imaging unit to confirm that all the heliostat azimuths and the field of view are correct, the first lens leaves the center position of the heat sink, for example, retracts to the underside of the heat sink. The second imaging unit acts as a monitoring task for the heliostats in the mirror field while the tower solar thermal power system is operating. The second imaging unit performs a photographing at each set time interval to form a current image. All the images captured by the second lens F in the second imaging unit can only be captured in the corresponding mirror field. The mirror M, as shown in Fig. 7, does not capture the virtual image of the sun in the heliostat M. Once the reflected light of the heliostat is just off the heat sink, one of the second imaging units The lens F can observe the virtual image of the sun. In the captured image, there is a virtual image of the sun. As shown in Figure 10, the k23 and k45 are fixed mirrors. At this point, the computer can determine which heliostat is deviated.

Once the cloud blocks the sun, it can be automatically tracked by the sun angle formula and the angle sensor. If it exceeds a certain time, the first imaging unit can be moved back to the center of the heat sink until the sun appears and all heliostats in the mirror field are corrected.

In Fig. 10, k34 and k45 do not necessarily appear on the same lens of the same second imaging unit, so all captured images of the entire second imaging unit need to be processed. 10 and 9 are photographs taken by the corresponding lens and the first imaging unit in the second imaging unit at the same time. Example 3

The present embodiment is directed to a correction method for generating an error due to movement when the imaging unit in the above embodiment moves relative to the mirror field.

The movement of the first imaging unit causes the deviation of the imaging, that is, the image formed after the two movements is different, which directly affects the accuracy of the correction; the wind or the mechanical cause also causes the images of the first and second imaging units. error. To solve this problem, you can use the following methods: In the fixed field where there is no heliostat in the mirror field, no less than 3 controllable laser emitters (or high-brightness light-emitting devices) that are not in a straight line can be installed. The first and second imaging units are covered, and the illumination frequency of the controllable laser emitter or the high-intensity illumination device corresponds to the photographing time interval. A mirror correction image including a controllable laser emitter or a high-intensity illumination device is captured by the first imaging unit and the second imaging unit, and the computer establishes pixel coordinate values of the position of the controllable laser emitter or the high-intensity illumination device through the corrected image . Based on the pixel coordinate value, a standard coordinate system is established, and it is determined that each center of the mirror field corresponds to the standard sitting a reference pixel coordinate of the calibration system; selecting a time point corresponding to the time interval, and performing imaging calculation of the heliostat pixel position relative to the coordinate system by imaging formed by the first lens, determining the current corresponding heliostat Pixel coordinates; compare the pixel coordinates of the current heliostat with the reference coordinates: If there is no difference in the pixel position, or the difference is within the set range, the corresponding heliostat does not need to be adjusted, such as the difference in pixel position exceeds the setting The range is determined, and the heliostats need to be adjusted. The adjustment is performed according to the steps described in the above embodiments 1 and 2. This eliminates the deviation caused by the movement of the imaging unit.

The planar heliostats of Embodiments 1 and 2 can be completely replaced with parabolic mirrors. In fact, the heliostat M in an ideal design is not a plane mirror, but rather a parabolic mirror. If an ideal parabolic mirror is formed that is focused on the lens of the imaging unit, the spot reflected by the sunlight to the position of the imaging unit is a point when the sun, the parabolic mirror, and the imaging unit are in a straight line. In the image observed or captured in the imaging unit, the entire parabolic mirror surface is exactly the evenly distributed sunlight. In fact, the spot of the parabolic mirror on the image taken by the imaging unit is an irregular bright block smaller than the heliostat, and the imaging unit observes uneven distribution of sunlight on the entire mirror surface of the parabolic mirror.

Claims

Claim

A method for detecting a heliostat angle deviation of a tower solar thermal power generation system, the tower solar thermal power generation system comprising a heat absorber fixed to the tower and a plurality of surface-defending mirrors rotatable at corresponding fixed positions, The plurality of surface heliostats are arranged in a set manner to form a mirror field, and each of the heliostats reflects sunlight to the heat absorber at the correct position, and is characterized in that the tower solar thermal power generation system is provided with a An imaging unit, the first imaging unit including a first lens E and a camera or camera connected to the first lens and a computer connected to the camera or the camera, the first lens being disposed in a central area of the heat sink And the distance from the mirror center Q _k of the _k- th surface of the mirror field is a constant value L _k , forming a first center line EQk, and the axis line of the heliostat rotating in the horizontal plane and the vertical plane passes through the mirror center Qk, The mirror image width _Qk of the mirror center Qk is Dk, and the height is _Hk . The first imaging unit can capture an image of the corresponding entire mirror field, and the image is used to determine whether the mirror position of the heliostat is positive. The exact steps are as follows:

1) Establish the coordinates of the mirror center

Adjusting all the heliostats in the mirror field so that the mirror surface is perpendicular to the first center line EQ _k , and then photographing the corresponding mirror field with the first imaging unit to form an initial image of the mirror field, through the initial image Establishing pixel coordinate values of the center of each heliostat as the center coordinates of the heliostat, and calculating the pixel amounts N _Dk and Ν contained in the linear direction of the mirror width 1\ and the height H _k _;

2) Find the center coordinates of the sun virtual image when the system works

When the tower solar thermal power generation system is in operation, the first imaging unit performs a shooting on the corresponding mirror field at each set time interval to form a current image of the mirror field, and the computer finds each side of the current image. The pixel coordinate value of the center Q' of the solar virtual image corresponding to the heliostat, as the central coordinate of the solar virtual image, and calculate the center of the solar virtual image Q' of each heliostat to the second center line EQ' of the lens 与 and the first center The azimuth angle formed by the angle of the connecting EQ on the horizontal plane and the elevation angle Φ formed on the vertical plane, the center of the solar virtual image of the k-th surface heliostat is Q _k ', and the second center line EQ _k ' of the lens E With the said A central connection EQk forms an azimuth angle of 8 _k and an elevation angle t) k;

3) Determine whether the mirror angle of the heliostat is correct

2. A method for detecting a heliostat angular deviation of a tower solar thermal power generation system, the tower solar thermal power generation system comprising a heat absorber fixed to the tower and a plurality of surface heliostats rotatable at corresponding fixed positions, The plurality of heliostats are arranged in a set manner to form a heliostat field, and each of the heliostats reflects sunlight to the heat absorber at the correct position, characterized in that the tower solar thermal power generation system is Providing a first imaging unit including a first lens E and a camera or camera connected to the first lens and a computer connected to the camera or the camera; the second imaging unit a plurality of second lenses, a plurality of cameras or cameras connected to the corresponding second lens, and a computer connected to the camera or the camera, the first lens being disposed in a central region of the heat sink and the kth in the mirror field from the surface of the heliostat centers Q _k is a constant value L _k, the first center connection formed Ε¾, heliostats in the horizontal and vertical axis of rotation of each mirror by center Q _k, The first imaging unit head can capture an image of the entire mirror field; the plurality of second lenses are disposed on the periphery of the heat absorber, and the distance between the adjacent two second lenses is smaller than the width or height of the minimum reflected spot The steps of determining whether the mirror position of the heliostat is correct by the images captured by the first and second imaging units are as follows - 1) establishing the center coordinates of the mirror field

Adjusting all the heliostats in the mirror field so that the mirror surface is perpendicular to the first center line EQ _k , respectively, using the first and second imaging units respectively to shoot the corresponding mirror field, forming an initial image corresponding to the mirror field, The initial image respectively establishes pixel coordinates corresponding to the center of each heliostat of the first and second imaging units The value is taken as the center coordinate of the heliostat, and the pixel quantities N _D and N _H included in the linear direction of the mirror width D and the height H are calculated _;

2) Find the sun image when the system works

When the tower solar thermal power generation system is in operation, the second imaging unit performs a shooting on the corresponding mirror field at each set time interval to form a current image of the mirror field, and the computer searches for each of the images. Whether there is a sun image in a heliostat;

3) Determine whether the mirror angle of the heliostat is correct

At the time interval, it is determined whether there is a solar virtual image in each of the heliostats in the current image. If there is no solar virtual image, the mirror angle of all the heliostats in the mirror field is correct, and the heliostat does not need to be adjusted, if there is a sun virtual image, corresponding The heliostat needs to be adjusted, and the azimuth angle and the vertical angle formed by the lens E to the second central line EQ of the center of the solar image of the corresponding heliostat and the first central line EQ are formed on the horizontal plane. The elevation angle Φ formed on the surface, the center of the solar virtual image of the k-th surface heliostat is Q _k ', and the second center line EQ _k ' to the lens E forms an azimuth angle of 6 _K with the first center line EQ _k and Elevation angle (i) _k .

The heliostat angle deviation detecting method of the tower type solar thermal power generation system according to claim 1 or 2, characterized in that the k-th surface heliostat has a horizontal rotation angle of 3 _k and a vertical rotation angle of 6 at the mirror surface. _{After 11} , the center Q _k ' of the solar virtual image coincides with the center Q _k of the mirror, and the distance from the center of the heliostat Q _k before the rotation to the center of the virtual image Q _k ' in the horizontal direction is L _DK pixels in the vertical direction. The upper pitch is a pixel amount, and the k-th surface heliostat horizontal rotation angle 3 _k , the vertical rotation angle S _k , the first lens to k-th surface heliostat center distance L _k , the k-th surface heliostat Azimuth angle 8 _K , width of k-th surface heliostat 1\, height of k-th surface heliostat, width of k-th surface heliostat width D in the linear direction N _Dk , k-th surface heliostat The amount of pixels Ν in the linear direction of height H, the center of the mirror Q _k to the center of the virtual image Q _k 'the amount of pixels L _DK in the horizontal direction, the center of the heliostat Q _k to the center of the virtual image Q _k ' in the vertical direction The pixel amount LHR of the upper interval has the following relationship - 6 _k =D _k Xn _Dk /N _Dk /L _k or * _k =H _k XnHk/NHk/L _k

P _k = 6 _k /2 or S _k = (J) _k /2.

The method for detecting a heliostat angle deviation of a tower solar thermal power generation system according to claim 1 or 2, wherein the first lens is disposed at a fixed position in a central region of the heat absorber, or is set In the U positioning positions of the central region of the heat absorber, the mirror field is divided into corresponding U regions, so that the first lens has a mirror field corresponding to each of the positioning positions.

The heliostat angle deviation detecting method of a tower solar thermal power generation system according to claim 1 or 2, wherein the heliostat is a plane mirror or a parabolic mirror.

6. The method for detecting a first imaging single movement error in a tower solar thermal power generation system according to claim 1 or 2 or 3 or 4, wherein at least the position of the amorphous heliostat in the mirror field is at least Providing 3 controllable laser emitters or high-intensity illumination devices not in a straight line, the light beams emitted by the emitters or high-intensity illumination devices can be imaged on the first and second imaging units, and the controllable laser emitters Or the illumination frequency of the high-intensity illumination device corresponds to the time interval, and the steps of correcting the movement error of the first imaging unit are as follows:

1) Establish the reference coordinates of the heliostat pixels

A mirror correction image including a controllable laser emitter or a high-intensity illumination device is captured by the first imaging unit or the second imaging unit, and the pixel coordinate value of the controllable laser emitter or the high-intensity illumination device is determined by the correction image, A pixel coordinate value is used as a reference to establish a standard coordinate system, and a reference pixel coordinate corresponding to the standard coordinate system of each certain day mirror in the mirror field is determined;

2) Determine the pixel coordinates of the current heliostat

Selecting a time point corresponding to the time interval, capturing a current mirror image with the first imaging unit, calculating a current mirror image with respect to a current heliostat pixel position of the standard coordinate system, and determining a corresponding heliostat Current pixel coordinates; 3) Discriminant error