WO2022007370A1

WO2022007370A1 - Heliostat optical path closed-loop control system and method

Info

Publication number: WO2022007370A1
Application number: PCT/CN2020/142173
Authority: WO
Inventors: 陈煜达; 陈昊; 孙楠; 沈平
Original assignee: 上海晶电新能源有限公司
Priority date: 2020-07-07
Filing date: 2020-12-31
Publication date: 2022-01-13
Also published as: CN111765657B; CN111765657A

Abstract

A heliostat optical path closed-loop control system and method, comprising a facula sensor (1), a heliostat rotation controller (2), and a computing unit (3); the facula sensor (1) is fixed on the heliostat, and rotates synchronously with the rotation of a target heliostat reflecting surface (5); the computing unit (3) is used to compute the offset between the actual position of the solar facula and the expected position, or to compute the offset between the actual and expected positions of a heliograph; the heliostat rotation controller (2) is fixed on the target heliostat; data exchange is conducted between the computing unit (3) and the heliostat rotation controller (2), and between the heliostat rotation controller (2) and the facula sensor (1). Via the use of the optical path reflection principle, the direction of an incident light or a reflecting light is controlled, achieving real time control of the heliostat orientation, effectively solving the problem of open-loop control methods being unable to make real-time corrections to heliostat orientation based on optical path feedback, realizing a real-time heliostat optical path closed-loop control system that is precise and efficient.

Description

A heliostat optical path closed-loop control system and method

technical field

The invention belongs to the technical field of solar thermal power generation, and in particular relates to a closed-loop control system and method for an optical path of a tower solar middle heliostat.

Background technique

As the core component of a tower solar thermal power station, the function of the heliostat is to reflect the sunlight that hits its surface to the target heat sink area. Since the position of the sun keeps changing with time, the heliostat needs to have sufficient control accuracy to ensure that the pointing accuracy of the reflected light meets the design requirements, that is, the sunlight reflected by the heliostat can continuously and accurately irradiate the target heat absorber area, so as to ensure the concentration efficiency of solar energy in the heat absorber area and the working efficiency of the solar thermal power station.

The existing heliostat control methods are based on open-loop control, the core of which is the motion model of the heliostat. Firstly, the heliostat motion model is obtained by iteratively calibrating the whiteboard and image collector, etc., and then the operation information required by the heliostat is estimated according to the calculation result of the sun position and the heliostat motion model, that is, the generation including the time , the operation table of the turning angle, and finally the heliostat transmission control mechanism controls the heliostat to rotate according to the operation table.

The open-loop control method of the heliostat has the following problems: 1) It needs a long debugging time. The open-loop control method relies on the motion model of the heliostat, and the control accuracy is ensured by correcting the motion model. The conventional motion model correction method is the calibration whiteboard method, that is, the sun spot of the target heliostat is reflected to the target calibration whiteboard area at different time periods, and then the image is analyzed by the image acquisition system to determine the actual position of the center of the reflected spot, and finally based on the time information. and the center position of the reflected light spot to solve the motion model of the target heliostat. Another heliostat motion model correction method is to install an image acquisition system on the heliostat that rotates with the rotation of the heliostat. The image acquisition system takes the sun or other celestial bodies with certain brightness as the target, The deviation of the position of the plane from the center of the image plane solves the motion model of the target heliostat. No matter what kind of heliostat motion model correction is adopted, it takes a long time to debug and iteratively correct the motion model. Only when the accuracy of the corrected motion model meets the design requirements, the deviation between the estimated operation information of the heliostat and the actual operation situation can meet the design requirements, and the accuracy of the open-loop control of the heliostat can be effectively guaranteed. 2) Real-time feedback is not available. The existing open-loop control method relies on the motion model to estimate the operation information of the heliostat, and performs unidirectional control based on sequential action on the heliostat, that is, the heliostat is only operated according to the estimated operation table during the actual rotation process. Rotation, it is impossible to give feedback on the accuracy of the actual posture of the heliostat, so it does not have the ability to automatically correct the deviation. Since the motion model is an abstract summary of the actual operation of the heliostat, the estimated result is only close to the actual situation, but cannot fully represent the actual situation. Therefore, the attitude of the heliostat controlled based on the motion model will be different from the actual target attitude. deviation. Due to the lack of real-time feedback, the heliostat cannot handle some abnormal situations, such as the uncorrectable imperfection of the model in some areas of the travel range, and the change of the surface shape caused by the wind. 3) The performance index of the mechanical transmission mechanism has high requirements. In order to ensure the accuracy and stability of the open-loop control, the heliostat mechanical transmission mechanism needs to have high performance index requirements, including repeatability accuracy requirements, rotation consistency requirements, etc. If the performance index is poor, that is, when the performance parameters such as repeatability accuracy and rotation consistency are poor, the rotation of the heliostat will show no obvious regularity, so that the motion model cannot accurately describe the actual rotation of the heliostat, which makes the opening and closing of the heliostat impossible. The attitude of the heliostat in the loop control state is uncontrollable. This will also affect the concentration efficiency of sunlight energy in the heat sink area, and even cause safety hazards due to the uncontrollable direction of the reflected light.

Therefore, a high-precision and high-efficiency heliostat optical path closed-loop control system is required to accurately correct the real-time attitude of the heliostat, so that the reflected sunlight spot can be accurately irradiated to the target area and ensure the concentration of solar energy in the heater area. Efficiency and photothermal conversion efficiency of solar thermal power plants.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention aims at the characteristics of high control precision of the heliostat in the tower solar thermal power generation technology, and uses the principle of optical path reflection to realize the real-time control of the attitude of the heliostat by controlling the direction of the incident light or the direction of the reflected light, which effectively solves the problem. The problem that the attitude of the heliostat cannot be corrected in real time based on the optical path feedback in the open-loop control mode is solved, and a high-precision, high-efficiency, real-time closed-loop control system of the heliostat optical path is realized.

The present invention is a closed-loop control system for the light path of a heliostat, comprising: a light spot sensor, a heliostat rotation controller and a calculation unit. The light spot sensor is fixed on the heliostat and rotates synchronously with the rotation of the reflective surface of the target heliostat. The calculation unit is used to calculate the actual position of the target heliostat sun spot or sun image, calculate the desired position of the target heliostat sun spot or sun image, calculate the deviation between the actual position of the sun spot and the desired position, or calculate the actual position of the sun image. The deviation from the desired position, the sun spot or sun image position deviation is converted into a correction value for the rotation of the heliostat. The heliostat rotation controller is fixed on the target heliostat, and its function is to control the rotation of the heliostat. Data is exchanged between the computing unit and the heliostat rotation controller in a wired or wireless form, and data exchange is performed between the heliostat rotation controller and the light spot sensor in a wired or wireless form .

The heliostat optical path closed-loop control system is classified into a reflective type and a direct type according to the different working modes of the spot sensor. The principle of the reflection type is to obtain the reflected light pointing information of the target heliostat at this moment by sensing the actual position of the sun spot; the principle of the direct type is to obtain the incident light pointing information of the target heliostat at this moment by sensing the actual position of the sun image.

The receiving surface of the spot sensor in the reflective heliostat optical path closed-loop control system faces the reflective surface of the target heliostat, and is used to receive the sunlight spot reflected by the reflective surface of the heliostat, and the normal of the receiving surface is reflected by the target heliostat. The value range of the angle δ between the surface normals is 90°<δ≤180°. The sunlight is reflected and irradiated to the target area, and a part of it is received by the receiving surface of the spot sensor to form a sun spot; the actual position of the sun spot can be described by the geometric center of the sun spot or the center of mass of the energy distribution, which represents the actual reflection of the target heliostat light points. The reflective optical path closed-loop control system senses the actual reflected light direction of the target heliostat through the spot sensor, and according to the deviation from the expected reflected light direction, the heliostat posture is corrected in real time to realize the real-time optical path closed-loop control of the heliostat.

The receiving surface of the spot sensor in the closed-loop control system of the direct-illuminated heliostat optical path is in the same direction as the reflective surface of the target heliostat (at the same time facing the sun), and the angle δ between the normal of the receiving surface and the normal of the reflective surface of the target heliostat is taken as The value range is 0°≤δ<90°. Part of the sunlight is received by the receiving surface of the spot sensor to form a sun image, and the rest of the sunlight is reflected to the target area through the heliostat reflecting surface; the actual position of the sun image can be described by the geometric center of the sun image or the energy distribution center of mass, which is characterized by The actual incident light pointing to the target heliostat. The direct-type optical path closed-loop control system senses the actual incident light direction of the target heliostat through the spot sensor. According to the deviation from the expected incident light direction, the heliostat posture is corrected in real time to realize the real-time optical path closed-loop control of the heliostat.

The work flow of the heliostat optical path closed-loop control system of the present invention is as follows:

(1) At time ti, the spot sensor collects the sun spot or solar image distribution information, and the computing unit calculates the actual position [u ^ti ,v ^ti ] _{n of the} sun spot or solar image based on the solar spot or solar image distribution information, where ti represents The i-th time point in a single working day, n represents the number of the heliostat, u ^ti represents the value of the u-axis direction of the actual position of the ^{sun spot or sun image at time ti} , and v ti represents the v of the actual position of the sun spot or sun image at time ti axis direction value;

(2) The calculation unit calculates the desired position information [Tu ^ti , Tv ^ti ] of the ^{sun spot or sun image of the target heliostat at time ti, where Tu ti} represents the u-axis direction value of the desired position of the sun spot or sun image at time ^ti , and Tv ti represents The value of the v-axis direction of the desired position of the sun spot or sun image at time ti;

(3) The calculation unit calculates the sun spot or sun image position deviation of the target heliostat [Δu ^ti ,Δv ^ti ] _n =[Tu ^ti -u ^ti ,Tv ^ti -v ^ti ] _n , Δu ^ti represents the sun spot or the sun spot at time ti The relative deviation between the expected coordinates and the actual coordinates in the u-axis direction of the sun image, Δv ^ti represents the relative deviation between the expected coordinates and the actual coordinates in the v-axis direction of the sun spot or the sun image at time ti;

(4) The heliostat rotation about at least two axes to achieve the function of reflected sunlight to the target area, the target calculation unit time ti heliostat sun or sun spot image position deviation mode according to the rotation of the heliostat [[Delta] u ^ti ,Δv ^ti ] _{n is} converted into the rotational deviation value of the heliostat.

The first rotation mode of the heliostat of the present invention is that the reflection surface of the heliostat rotates around two mutually orthogonal rotation axes X-axis and Y-axis, wherein the position of the Y-axis remains unchanged, and the X-axis rotates around the Y-axis with the reflection surface of the heliostat. Rotational deviation value:

In the formula: u _1/2 represents the u-axis coordinate of the center of the receiving surface, v _1/2 represents the v-axis coordinate of the receiving surface center, d represents the distance from the receiving surface to the heliostat reflective surface,

represents the rotational deviation of the X-axis,

Indicates the Y-axis rotational deviation.

The second rotation mode of the heliostat in the present invention is that the mirror surface of the heliostat rotates around two mutually orthogonal rotation axes, the Y axis and the Z axis, wherein the position of the Z axis remains unchanged, and the Y axis rotates around the Z axis with the heliostat reflecting surface. Rotational deviation value:

where:

Indicates the Z-axis rotational deviation.

(5) The heliostat rotation controller corrects the target heliostat attitude at time ti in real time according to the rotation deviation value, so that the actual position [u ^ti , v ^ti ] _{n of the} sun spot or sun image is constantly approaching or overlapping the desired position [Tu ^{ti ]} , Tv ^ti ];

(6) In a single working day, repeat steps (1)-(5), the calculation unit uses the deviation between the actual position of the sun spot or the sun image and the expected position as feedback, and continuously corrects the posture of the target heliostat in real time, so that at any time The actual position of the sun spot or sun image fluctuates near the desired position, realizing the closed-loop control of the light path of the heliostat to ensure that the reflected light of the heliostat can be directed to the target area correctly.

The steps of calculating the desired position of the target heliostat sun spot or sun image by the calculation unit in the heliostat closed-loop control system of the present invention are as follows:

(1) The calculation unit is based on the center coordinates of the target heliostat at time ti

Calculate the normalized reflection vector at this moment with the target pointing point [tx _n ,ty _n ,tz _{n ]:}

where || represents the modulo operation,

Represents the value of the X-axis direction of the center coordinate of the target heliostat at time ti,

Represents the value of the Y-axis direction of the center coordinate of the target heliostat at time ti,

Represents the value of the Z-axis direction of the center coordinate of the target heliostat at time ti, tx _n represents the value of the X-axis direction of the coordinate of the target pointing point at time ti, ty _n represents the value of the Y-axis direction of the coordinate of the target pointing point at time ti _{, and tz n represents the value of the target pointing point at time ti} The value of the coordinate Z-axis direction,

represents the X-axis direction component of the normalized reflection vector at time ti,

represents the Y-axis direction component of the normalized reflection vector at time ti,

Represents the Z-axis direction component of the normalized reflection vector at time ti;

(2) The computing unit calculates the normalized sunlight incident vector at time ti

Represents the X-axis direction component of the normalized sunlight incident vector at time ti,

Represents the Y-axis direction component of the normalized sunlight incident vector at time ti,

Represents the Z-axis direction component of the normalized sunlight incident vector at time ti; (3) the computing unit calculates the normalized normal vector of the heliostat reflecting surface at this time:

where:

represents the X-axis direction component of the normalized normal vector of the heliostat reflecting surface at time ti,

represents the Y-axis direction component of the normalized normal vector of the heliostat reflecting surface at time ti,

Represents the Z-axis direction component of the normalized normal vector of the heliostat reflecting surface at time ti;

_{(4) The angle δ=[δ n} δ _u δ _v ] between the normal vector of the receiving surface of the spot sensor and the normal vector of the heliostat reflective surface, where δ _n represents the distance around the normal vector of the heliostat reflective surface Deviation angle, δ _u represents the deviation angle around the u-axis, and δ _v represents the deviation angle around the v-axis; in the closed-loop control system of the reflective heliostat, the value of δ is in the range of 90°≤δ<180°. The value range of δ in the closed-loop control system is 0°≤δ<90°; the calculation unit calculates the normal vector of the receiving surface based on the angle δ between the normal vector of the receiving surface of the spot sensor and the normal vector of the reflecting surface of the heliostat:

In the formula: n represents the number of the heliostat, Rot _u () represents the rotation matrix around the u-axis, Rot _v () represents the rotation matrix around the v-axis, and Rot _n () represents the rotation around the normal vector of the heliostat reflecting surface matrix,

Represents the X-axis direction component of the normalized normal vector of the receiving surface of the spot sensor at time ti,

Represents the Y-axis direction component of the normalized normal vector of the receiving surface of the spot sensor at time ti,

Represents the Z-axis direction component of the normalized normal vector of the receiving surface of the spot sensor at time ti;

(5) In the closed-loop control system of the reflective heliostat, the calculation unit receives the center coordinates of the receiving surface according to the time ti

and the receiving surface normal vector

Establish the three-dimensional equation of the receiving surface, and then according to the sunlight reflection vector at time ti

and heliostat center coordinates

Establish a three-dimensional straight line equation system based on the mirror surface of the heliostat, and solve the coordinates of the intersection point between the reflected light and the receiving surface

where k represents the Kth intersection; finally, the coordinates of the intersection are converted to the coordinate system of the receiving surface to obtain the desired position coordinates of the sun spot [Tu ^ti , Tv ^ti ].

In the closed-loop control system of the direct-illuminated heliostat, the calculation unit receives the center coordinates of the surface according to the time ti

and the receiving surface normal vector

Establish the three-dimensional equation of the receiving surface, and then according to the incident vector of sunlight at time ti

and heliostat center coordinates

Establish a three-dimensional straight line equation system based on the reflecting surface of the heliostat, and solve the coordinates of the intersection of the incident light pointing and the receiving surface

Where k represents the K-th intersection, and finally the coordinates of the intersection are converted to the coordinate system of the receiving surface to obtain the desired position coordinates of the sun image [Tu ^ti , Tv ^ti ].

In the present invention, the spot sensor in the reflective optical circuit closed-loop control system is composed of an image acquisition array composed of at least one image acquisition device, and the image acquisition device is composed of an imaging optical path (lens or small holes, etc.), a light intensity attenuation device and Image sensor composition. The sunlight is reflected by the reflecting surface of the heliostat to the image surface of the image acquisition array to form a sun spot. The lens of the image collector faces the reflective surface of the heliostat, and the number of image collectors is determined according to the size of the reflective surface of the heliostat, so that the field of view formed by the image acquisition array can cover the area of the reflective surface of the heliostat.

The actual position recognition of the sun spot with the image acquisition array as the spot sensor includes the following steps:

(1) The image acquisition array collects the image of the reflective surface of the heliostat;

(2) Obtain the area range of the sun spot in each image collector at time ti by the binarization method;

(3) Calculate the geometric center of the sun spot at this moment based on the sun spot area in the binarized image, or calculate the centroid of the energy distribution of the sun spot at this moment based on the sun spot area in the grayscale or color image, then the actual position of the sun spot (geometric center or The image coordinates of the energy distribution centroid) are expressed as

Where m represents the number of the image collector, n represents the number of the heliostat, h represents the number of pixels in the u-axis direction of the actual position of the sun spot at time ti, and l represents the number of pixels in the v-axis direction of the actual position of the sun spot at time ti.

In the reflective optical path closed-loop control system, the light spot sensor may be composed of an array composed of photoelectric sensors and a diaphragm. The photoelectric sensors include non-imaging sensors based on photoelectric effect, such as photoresistors, photodiodes, and optical switches. The receiving surface of the photoelectric sensor faces the reflective surface of the heliostat, and the number of the photoelectric sensors is determined according to the reflection range of the reflective surface of the heliostat, so that the receiving surface composed of the photoelectric sensor array can cover the sun reflected by the reflective surface area of the heliostat. spot. The sunlight is reflected by the reflecting surface of the heliostat to the receiving surface of the photoelectric sensor array, and the electric signal intensity distribution of the receiving surface generated by the sun spot is obtained. The diaphragm is used to limit the range of sunlight irradiated to the spot sensor so as to form a sunlight spot.

The light spot sensor in the reflective optical path closed-loop control system may be composed of an array composed of photoelectric sensors and a standard plane mirror. The photoelectric sensors include non-imaging sensors based on photoelectric effect, such as photoresistors, photodiodes, and optical switches. The standard plane mirror is installed on the target heliostat and rotates synchronously with the mirror surface of the heliostat. The size of the standard plane mirror is determined by the size of the photoelectric sensor and the distance between the photoelectric sensors. The mirror reflecting surfaces are in the same direction (facing the sun at the same time) and their relative positions are fixed. The receiving surface of the photoelectric sensor faces the reflective surface of the standard flat mirror, and the number of photoelectric sensors is determined according to the reflection range of the standard flat mirror, so that the receiving surface formed by the photoelectric sensor array can cover the sunlight spot reflected by the standard flat mirror . The sunlight is reflected to the receiving surface of the photoelectric sensor array through the reflective surface of the standard plane mirror, and the electric signal intensity distribution of the receiving surface generated by the sun spot is obtained.

The above-mentioned identification of the actual position of the sun spot using the photoelectric sensor array as the spot sensor includes the following steps:

(1) The photoelectric sensor array obtains the electrical signal intensity distribution of the receiving surface;

(2) According to the electrical signal intensity distribution, based on a preset threshold, obtain the photoelectric sensor range illuminated by the sun spot on the photoelectric sensor array receiving surface at time ti, that is, the lighted photoelectric sensor range;

(3) Calculate the geometric center based on the range of the illuminated photoelectric sensor, or calculate the energy distribution centroid based on the electrical signal intensity distribution within the illuminated photoelectric sensor range, then the actual position of the sun spot (geometric center or energy distribution centroid) coordinates are expressed as [Ou ^ti ,Ov ^ti ] _n , where n represents the number of the heliostat, Ou represents the value of the photoelectric sensor array in the u-axis direction of the actual position of the sun spot at time ti, and Ov represents the value of the photoelectric sensor array in the v-axis direction of the actual position of the sun spot at time ti .

The light spot sensor in the reflective optical path closed-loop control system may be composed of a receiving board, an image acquisition array composed of at least one image acquisition device, and a standard plane mirror. The image collector is composed of an imaging optical path and an image sensor. The receiving surface of the receiving plate is a diffuse reflection surface, and the receiving surface faces the reflecting surface of the standard plane reflector, and is used for receiving sunlight reflected by the reflecting surface of the standard plane reflector. The size of the receiving plate covers the reflection range of a standard flat mirror. The standard plane mirror is installed on the target heliostat and rotates synchronously with the rotation of the mirror surface of the heliostat. The size of the standard flat mirror is determined by the resolution of the image acquisition array, and the reflective surface of the standard flat mirror and the reflective surface of the heliostat are in the same direction (facing the sun at the same time) and have a fixed relative position. The lens in the image acquisition array faces the receiving surface of the receiving plate, and the number of image collectors is determined according to the size of the receiving plate, which is used to identify the actual position of the sun spot on the receiving plate, so that the field of view composed of the image acquisition array can cover the receiving plate area. The above-mentioned recognition of the actual position of the sun spot using the receiving plate, the image acquisition array and the standard plane reflector as the spot sensor of the present invention includes the following steps:

(1) The receiving plate receives the sunlight spot reflected by the reflective surface of the standard plane mirror;

(2) Collect the image of the receiving plate through the image collector array, and identify the sun spot area at time ti by the binarization method;

(3) Taking the center of the receiving plate as the origin, calculate the geometric center of the sun spot at this moment based on the sun spot area in the binarized image, or calculate the centroid of the energy distribution of the sun spot at this moment based on the sun spot area in the grayscale image or color image, then The actual coordinates of the actual position of the sun spot (geometric center or energy distribution centroid) on the receiving plate [By ^ti , Bx ^ti ] _n , where By represents the u-axis value of the receiving plate at the actual position of the sun spot at time ti, and Bx represents the sun at time ti The value of the receiving plate v-axis direction of the actual position of the light spot.

In the present invention, the light spot sensor in the direct-type optical path closed-loop control system is composed of an image acquisition array composed of at least one image acquisition device. The image collector consists of an imaging optical path (lens or small hole, etc.), a light intensity attenuation device and an image sensor. The field of view formed by the image acquisition array covers the moving range of the sun relative to the target heliostat. The lens of the image collector is pointed in the same direction as the reflective surface of the heliostat (at the same time facing the sun), and the sun image is directly collected, which is used to identify the relative position of the actual position of the sun image in the field of view of the image collection array.

The above-mentioned recognition of the actual position of the sun image using the image acquisition array as the spot sensor includes the following steps:

(1) The image acquisition array collects images of the sun;

(2) Obtain the area of the sun image in each image collector at time ti by the binarization method;

(3) Calculate the geometric center of the sun image at this moment based on the sun image area in the binarized image, or calculate the centroid of the energy distribution of the sun image at this moment based on the sun image area in the grayscale or color image, then the actual position of the sun image (geometric center or The image coordinates of the energy distribution centroid) are expressed as

Among them, m represents the number of the image collector, h represents the number of pixels in the u-axis direction of the actual position of the sun image at time ti, l represents the number of pixels in the v-axis direction of the actual position of the sun image at time ti, and n represents the number of heliostats.

Beneficial effects of the present invention:

(1) The present invention is an optical circuit closed-loop control system, which dynamically corrects the posture of the heliostat according to the deviation between the actual position and the desired position of the sun spot or sun image at any time, without the need for a motion model of the heliostat, nor based on motion Operational table for model calculations.

(2) The present invention utilizes the principle of light path reflection to realize the closed-loop control of the light path of the heliostat by controlling the direction of the incident light or the direction of the reflected light. Since it does not depend on the motion model of the heliostat, it does not require a long debugging time to correct the motion of the heliostat. After the installation of the heliostat is completed, the conventional heat collection and power generation work can be carried out, which can effectively improve the opening efficiency of the tower solar thermal power station.

(3) The present invention can realize the closed-loop control of the light path of the heliostat, identify the actual position of the sun spot or the sun image based on the spot sensor, and then calculate the center position deviation from the desired position, and use this as feedback to realize the dynamic correction of the heliostat attitude. , which can effectively ensure the heat collection and power generation efficiency of the heliostat.

(4) The present invention does not drive the heliostat to rotate based on the calculation of the operation table of the heliostat movement model, and does not require a higher performance index of the mechanical transmission mechanism to ensure the open-loop control accuracy of the heliostat. Since the attitude of the heliostat can be corrected in real time according to the actual position of the sun spot or the actual position of the sun image, there is no need to put forward higher requirements on the performance indicators such as repeatability accuracy requirements and rotational consistency requirements of the transmission mechanism, thereby effectively reducing the mechanical properties of heliostats. Transmission manufacturing cost.

(5) The present invention can correct the deformation of the heliostat mirror surface caused by wind vibration, gravity, etc. by implementing the optical path closed-loop control on the heliostat, thereby effectively improving the adaptability of the heliostat to the environment.

Description of drawings

1 is a schematic diagram of a reflective heliostat optical path closed-loop control system of the present invention;

Fig. 2 is the schematic diagram of the closed-loop control system of the direct-illuminated heliostat optical path of the present invention;

Figure 3 is a schematic diagram of the deviation of the sun spot or the sun image from the center;

4 is a schematic diagram of a rotation mode of the heliostat according to an embodiment of the present invention;

Fig. 5 is the rotational deviation numerical decomposition schematic diagram based on heliostat rotation mode 1;

FIG. 6 is a schematic diagram of a second rotation mode of the heliostat according to the embodiment of the present invention;

Fig. 7 is the rotational deviation numerical decomposition schematic diagram based on heliostat rotation mode 2;

8 is a schematic diagram of a reflective light spot sensor based on an image acquisition array;

9 is a schematic diagram of the actual position of the sun spot of a reflective spot sensor based on an image acquisition array;

10 is a schematic diagram of a reflective light spot sensor based on a photoelectric sensor;

Figure 11 is a schematic diagram of a reflective spot sensor based on a photoelectric sensor and a standard mirror;

Figure 12 is a schematic diagram of the actual position of the sun spot based on the photoelectric sensor;

13 is a schematic diagram of a reflective light spot sensor based on a receiving plate;

Figure 14 is a schematic diagram of the actual position of the sun spot based on the receiving plate;

FIG. 15 is a schematic diagram of a direct light spot sensor based on an image acquisition array;

FIG. 16 is a schematic diagram of the actual position of the solar image of the direct light spot sensor based on the image acquisition array.

detailed description

The present invention will be further described below with reference to the accompanying drawings.

In the figure: 1-spot sensor, 2-heliostat rotation controller, 3-calculation unit calculation unit, 4-receiving surface, 5-heliostat reflective surface, 6-target area, 7-actual reflected light direction, 8- Desired reflected light direction, 9- Actual incident light direction, 10- Desired incident light direction, 11- Image collector, 12- Photoelectric sensor, 13- Diaphragm, 14- Standard plane mirror, 15- Receiver plate, 16 - Image acquisition array.

A heliostat optical path closed-loop control system of the present invention includes: a light spot sensor 1 , a heliostat rotation controller 2 and a calculation unit calculation unit 3 . The spot sensor 1 is fixed on the heliostat reflective surface 5 and rotates synchronously with the rotation of the target heliostat reflective surface 5 . The closed-loop control system of the heliostat light path is divided into reflective type and direct irradiation type according to the working mode of the spot sensor 1. The principle of the reflective type is to obtain the reflected light pointing information of the target heliostat at this moment by sensing the actual position of the sun spot, and the direct irradiation The principle of the formula is to obtain the incident light pointing information of the target heliostat at this moment by sensing the actual position of the sun image. Calculation unit The calculation unit 3 is used to calculate the actual position of the target heliostat sun spot or sun image, calculate the desired position of the target heliostat sun spot or sun image, calculate the deviation between the actual position of the sun spot and the desired position, or calculate the actual position of the sun image. The deviation of the position from the expected position, and the position deviation of the sun spot or the sun image is converted into a correction value for the rotation of the heliostat. The heliostat rotation controller 2 is fixed on the target heliostat, and its function is to control the rotation of the heliostat. Computing Unit The computing unit 3 and the heliostat rotation controller 2 perform data exchange in a wired or wireless form, and the heliostat rotation controller 2 and the light spot sensor 1 perform data exchange in a wired or wireless manner.

Example 1

As shown in FIG. 1 , a reflective heliostat optical path closed-loop control system of the present invention, wherein the receiving surface 4 of the spot sensor 1 faces the reflective surface of the target heliostat reflective surface 5 , and is used to receive the reflective surface 5 of the heliostat. Reflected sun spots. The sunlight is reflected and irradiated to the target area 6 , a part of which is received by the receiving surface 4 of the spot sensor 1 to form a sunlight spot, and the actual position of the sunlight spot represents the actual reflected light direction 7 of the target heliostat. The reflective optical path closed-loop control system senses the actual reflected light direction 7 of the target heliostat through the spot sensor 1, and according to the deviation from the expected reflected light direction 8, the heliostat posture is corrected in real time to realize the real-time optical path of the heliostat. Closed-loop control.

Example 2

As shown in FIG. 2 , a direct-type heliostat optical path closed-loop control system of the present invention, wherein the receiving surface 4 of the spot sensor 1 and the reflecting surface of the target heliostat reflecting surface 5 are in the same direction (facing the sun at the same time). Part of the sunlight is received by the receiving surface 4 of the spot sensor 1 to form a sun image, and the rest of the sunlight is reflected to the target area 6 through the heliostat reflective surface 5. The actual position of the sun image represents the actual incident light direction of the target heliostat 9 . The direct-type optical path closed-loop control system senses the actual incident light direction 9 of the target heliostat through the spot sensor 1, and according to the deviation from the expected incident light direction 10, the heliostat posture is corrected in real time to realize the real-time optical path of the heliostat. Closed-loop control.

Example 3

The control method of the heliostat optical path closed-loop control system of the present invention is as follows:

(1) As shown in FIG. 3 , the spot sensor 1 collects the sun spot or the sun image distribution information at time ti, and the calculation unit 3 calculates the actual position of the sun spot or the sun image based on the sun spot or the sun image distribution information [u ^ti , v ^ti ] _n , where ti represents the ith time point in a single working day, n represents the number of heliostats, u ^ti represents the actual coordinates of the u-axis direction of the actual position of the sun spot or sun image ^{at time ti} , and v ti represents time ti The actual coordinates of the v-axis direction of the actual position of the sun spot or sun image;

(2) Calculation unit The calculation unit 3 calculates the desired position information [Tu ^ti , Tv ^ti ] of the ^{sun spot or sun image of the target heliostat at time ti, where Tu ti} represents the desired coordinate in the u-axis direction of the sun spot or sun image at time ti, Tv ^ti represents the desired coordinates of the sun spot or sun image in the v-axis direction at time ti;

(3) The calculation unit 3 calculates the sun spot or sun image position deviation of the target heliostat [Δu ^ti ,Δv ^ti ] _n =[Tu ^ti -u ^ti ,Tv ^ti -v ^ti ] _n , where Δu ^ti represents the sun spot at time ti Or the relative deviation between the expected coordinates and the actual coordinates in the u-axis direction of the sun image, Δv ^ti represents the relative deviation between the expected coordinates and the actual coordinates of the sun spot or the v-axis direction of the sun image at time ti;

(4) The heliostat rotates around at least two axes to realize the function of reflecting sunlight to the target area 6, and the calculation unit 3 calculates the position deviation of the target heliostat sun spot or sun image at time ti according to the rotation mode of the heliostat [ Δu ^ti ,Δv ^ti ] _{n is} converted into the rotational deviation value of the heliostat.

As shown in FIG. 4 , a first rotation method of the heliostat according to the present invention, the heliostat reflective surface 5 rotates around two mutually orthogonal rotation axes X-axis and Y-axis, wherein the position of the Y-axis remains unchanged, and the X-axis changes with the fixed axis. The heliostat reflecting surface 5 rotates around the Y axis. As shown in Figure 5, the rotational deviation value:

In the formula: u _1/2 represents the u-axis coordinate of the center of the receiving surface, v _1/2 represents the v-axis coordinate of the receiving surface center, d represents the distance from the receiving surface to the heliostat reflective surface 5,

Indicates the X-axis angle deviation,

Indicates the Y-axis angle deviation.

As shown in FIG. 6 , a second rotation mode of the heliostat according to the present invention, the heliostat reflective surface 5 rotates around two mutually orthogonal rotation axes Y-axis and Z-axis, wherein the position of the Z-axis remains unchanged, and the Y-axis changes with the fixed axis. The heliostat reflecting surface 5 rotates around the Z axis. As shown in Figure 7, the rotational deviation value:

where:

Indicates the Z-axis angle deviation.

(5) The heliostat rotation controller 2 corrects the posture of the target heliostat at time ti in real time according to the rotation deviation value, so that the actual position [u ^ti , v ^ti ] _{n of the} sun spot or the sun image continuously approaches or coincides with the desired position [Tu ti , v ti ] n ^ti , Tv ^ti ];

(6) In a single working day, repeat steps (1)-(5), the calculation unit 3 uses the deviation between the actual position of the sun spot or the sun image and the expected position as feedback, and continuously corrects the posture of the target heliostat in real time, so that any The actual position of the sun spot or the sun image fluctuates near the desired position at any time, so as to realize the closed-loop control of the light path of the heliostat, and to ensure that the reflected light of the heliostat can be correctly irradiated to the target area 6 .

In the heliostat closed-loop control system of the present invention, the calculation unit calculation unit 3 calculates the desired position of the target heliostat sun spot or sun image as follows:

(1) Calculation unit The calculation unit 3 is based on the center coordinates of the target heliostat at time ti

where || represents the modulo operation,

(2) Calculation unit The calculation unit 3 calculates the normalized sunlight incident vector at time ti

Represents the Z-axis direction component of the normalized sunlight incident vector at time ti;

(3) calculation unit The calculation unit 3 calculates the normalized normal vector of the heliostat reflecting surface 5 at this moment:

where:

represents the X-axis direction component of the normalized normal vector of the heliostat reflecting surface 5 at time ti,

represents the Y-axis direction component of the normalized normal vector of the heliostat reflecting surface 5 at time ti,

Represents the Z-axis direction component of the normalized normal vector of the heliostat reflecting surface 5 at time ti;

_{(4) The angle δ=[δ n} δ _u δ _v ] between the normal vector of the receiving surface 4 of the spot sensor and the normal vector of the heliostat reflective surface 5, where δ _n represents the method around the heliostat reflective surface 5 The deviation angle of the line vector, δ _u represents the deviation angle around the u axis, δ _v represents the deviation angle around the v axis; the value range of δ in the closed-loop control system of the reflection heliostat is 90°≤δ＜180°, the direct type The value range of δ in the heliostat closed-loop control system is 0°≤δ<90°; calculation unit Calculation unit 3 is based on the angle between the normal vector of the receiving surface 4 of the spot sensor 1 and the normal vector of the reflective surface 5 of the heliostat δ calculates the normal vector of the receiving surface 4:

(5) In the closed-loop control system of the reflective heliostat, the calculation unit The calculation unit 3 receives the center coordinates of the surface 4 according to the time ti

and the receiving surface 4 normal vector

Establish the three-dimensional equation of the receiving surface 4, and then according to the sunlight reflection vector at time ti

and heliostat center coordinates

Establish a three-dimensional straight line equation system based on the heliostat reflective surface 5, and solve the coordinates of the intersection point between the reflected light and the receiving surface 4

where k represents the Kth intersection; finally, the coordinates of the intersection are converted to the coordinate system of the receiving surface 4 to obtain the desired coordinates of the sun spot [Tu ^ti , Tv ^ti ].

in

Respectively represent the values of the x-axis, y-axis and z-axis directions of the center coordinates of the heliostat receiving surface 4 with the number n at time ti;

Respectively represent the x-axis, y-axis and z-axis direction components of the normal vector of the heliostat receiving surface numbered n at time ti;

Respectively represent the values in the x-axis, y-axis and z-axis directions of the intersection coordinates of the heliostat reflected light at time ti numbered n and the receiving surface 4 .

In the closed-loop control system of the direct-illuminated heliostat, the calculation unit 3 receives the center coordinates of the surface 4 according to the time ti

and the receiving surface 4 normal vector

The three-dimensional equation of the receiving surface 4 is established, and then according to the incident vector of sunlight at time ti

and heliostat center coordinates

Establish a three-dimensional linear equation system based on the heliostat reflecting surface 5, and solve the coordinates of the intersection point between the incident light direction and the receiving surface 4

Where k represents the K-th intersection, and finally the coordinates of the intersection are converted to the 4 coordinate system of the receiving surface to obtain the desired coordinates [Tu ^ti , Tv ^ti ] of the sun image.

in

Respectively represent the values in the x-axis, y-axis and z-axis directions of the intersection coordinates of the heliostat incident light with the number n at time ti and the receiving surface 4 .

Example 4

As shown in FIG. 8 , the spot sensor 1 in the reflective optical path closed-loop control system is composed of an image acquisition array composed of at least one image acquisition device 11 . It consists of a light intensity attenuation device and an image sensor. The sunlight is reflected by the reflecting surface of the heliostat reflecting surface 5 to the image surface of the image acquisition array to form a sun spot. The lens of the image collector 11 faces the reflective surface of the heliostat reflective surface 5 , and the number of image collectors 11 is determined according to the size of the heliostat reflective surface 5 , so that the field of view formed by the image acquisition array can cover the area of the heliostat reflective surface 5 .

(1) The image acquisition array acquires the image of the heliostat reflective surface 5;

(2) As shown in FIG. 9 , the area range of the sun spot in each image collector 11 at time ti is obtained by the binarization method;

Example 5

As shown in FIG. 10 , the light spot sensor 1 in the reflective optical circuit closed-loop control system may be composed of an array composed of photoelectric sensors 12 and a diaphragm 13 . The photoelectric sensor 12 includes non-imaging sensors based on photoelectric effect, such as photoresistor, photodiode, and optical switch. The receiving surface of the photoelectric sensor 12 faces the reflective surface of the heliostat reflective surface 5, and the number of the photoelectric sensors 12 is determined according to the reflection range of the heliostat reflective surface 5, so that the receiving surface composed of the photoelectric sensor array can cover the heliostat The sun spot reflected by the reflective surface 5 area. The sunlight is reflected to the receiving surface of the photoelectric sensor array through the reflective surface of the heliostat reflective surface 5, and the intensity distribution of the electrical signal on the receiving surface generated by the sun spot is obtained. The diaphragm 13 is used to limit the range of sunlight irradiated to the spot sensor 1 so as to form a sunlight spot.

Example 6

As shown in FIG. 11 , the light spot sensor 1 in the reflective optical circuit closed-loop control system may be composed of an array composed of photoelectric sensors 12 and a standard plane mirror 14 . The photoelectric sensor 12 includes non-imaging sensors based on photoelectric effect, such as photoresistor, photodiode, and optical switch. The standard plane mirror 14 is installed on the target heliostat and rotates synchronously with the rotation of the heliostat reflective surface 5. The size of the standard plane mirror 14 is determined by the size of the photoelectric sensor 12 and the distance between the photoelectric sensors 12. The standard plane reflects The reflecting surface of the mirror 14 is in the same direction as the reflecting surface of the heliostat reflecting surface 5 (at the same time facing the sun). The receiving surface of the photoelectric sensor 12 faces the reflective surface of the standard flat mirror 14, and the number of the photoelectric sensors 12 is determined according to the reflection range of the standard flat mirror 14, so that the receiving surface composed of the photoelectric sensor array can cover the standard flat mirror 14 reflected sun spots. The sunlight is reflected to the receiving surface of the photoelectric sensor array through the reflective surface of the standard plane reflector 14 to obtain the electrical signal intensity distribution on the receiving surface generated by the sun spot.

In

Embodiments

5 and 6, the actual position recognition of the sun spot with the photoelectric sensor array as the spot sensor includes the following steps:

(2) As shown in FIG. 12 , according to the electrical signal intensity distribution, the range of the photoelectric sensor 12 irradiated by the sun spot on the receiving surface of the photoelectric sensor array at time ti is obtained based on a preset threshold, that is, the range of the photoelectric sensor 12 that is lit;

(3) Calculate the geometric center based on the range of the illuminated photoelectric sensor 12, or calculate the energy distribution centroid based on the electrical signal intensity distribution within the illuminated photoelectric sensor 12, then the actual position of the sun spot (geometric center or energy distribution centroid) coordinates Expressed as [Ou ^ti ,Ov ^ti ] _n , where n represents the heliostat number, Ou represents the u-axis value of the photoelectric sensor array at the actual position of the sun spot at time ti, and Ov represents the v-axis of the photoelectric sensor array at the actual position of the sun spot at time ti direction value.

Example 7

As shown in FIG. 13 , the spot sensor 1 in the reflective optical path closed-loop control system may be composed of a receiving plate 15 , an image acquisition array 16 composed of at least one image acquisition device, and a standard plane mirror 14 . The receiving surface of the receiving plate 15 is a diffuse reflection surface, and the receiving surface faces the reflecting surface of the standard plane reflector 14 for receiving sunlight reflected by the reflecting surface of the standard plane reflector 14 . The size of the receiving plate 15 covers the reflection range of the standard flat mirror 14 . The standard plane mirror 14 is installed on the target heliostat and rotates synchronously with the rotation of the heliostat reflective surface 5 . The size of the standard plane mirror 14 is determined by the resolution of the image acquisition array 16, and the reflection surface of the standard plane mirror 14 and the reflection surface of the heliostat reflection surface 5 are in the same direction (and face the sun at the same time). The lens in the image acquisition array 16 faces the receiving surface of the receiving plate 15, and the number of image collectors is determined according to the size of the receiving plate 15, and is used to identify the actual position of the sun spot on the receiving plate 15, so that the field of view formed by the image acquisition array 16 can cover Receiving plate 15 area.

The above-mentioned recognition of the actual position of the sun spot with the receiving plate 15, the image acquisition array 16 and the standard plane mirror 14 as the spot sensor includes the following steps:

(1) The receiving plate 15 receives the sunlight spot reflected by the reflection surface of the standard plane mirror 14;

(2) Collect the image of the receiving plate through the image collector array 16, and identify the sun spot area at time ti by the binarization method;

(3) As shown in FIG. 14 , take the center of the receiving plate 15 as the origin, calculate the geometric center of the sun spot at this moment based on the sun spot area in the binarized image, or calculate the moment based on the sun spot area in the grayscale image or the color image Sun spot energy distribution centroid, then the actual coordinates of the actual position (geometric center or energy distribution centroid) of the sun spot on the receiving plate 15 [By ^ti , Bx ^ti ] _n , where By represents the receiving plate u-axis of the actual position of the sun spot at time ti The direction value, Bx represents the value of the receiving plate v-axis direction of the actual position of the sun spot at time ti.

Example 8

As shown in FIG. 15 , the light spot sensor 1 in the direct-type optical path closed-loop control system is composed of an image acquisition array composed of at least one image acquisition device 11 . The image collector 11 is composed of an imaging optical path (lens or a small hole, etc.), a light intensity attenuation device and an image sensor. The field of view formed by the image acquisition array covers the moving range of the sun relative to the target heliostat. The lens of the image collector 11 points in the same direction as the reflection surface of the heliostat reflective surface 5 (at the same time facing the sun), and directly collects the sun image, which is used to identify the relative position of the actual position of the sun image in the field of view of the image acquisition array.

The above-mentioned recognition of the actual position of the sun image using the image acquisition array as the spot sensor 1 includes the following steps:

(1) The image acquisition array collects images of the sun;

(2) As shown in FIG. 16 , the area of the sun image in each image collector 11 at time ti is obtained by the binarization method;

Aiming at the characteristics of high control precision of the heliostat in the tower type solar thermal power generation technology, the invention utilizes the principle of optical path reflection to realize the real-time control of the attitude of the heliostat by controlling the direction of the incident light or the direction of the reflected light, and effectively solves the open-loop control method. The problem that the attitude of the heliostat cannot be corrected in real time based on the optical path feedback, a high-precision, high-efficiency, real-time closed-loop control system of the heliostat optical path is realized.

Claims

A heliostat optical path closed-loop control system is characterized by comprising: a light spot sensor, a heliostat rotation controller and a calculation unit; the light spot sensor is fixed on the heliostat and rotates with the reflective surface of the target heliostat and rotate synchronously;

The calculation unit is used to calculate the actual position of the target heliostat sun spot or sun image, calculate the desired position of the target heliostat sun spot or sun image, calculate the deviation between the actual position of the sun spot and the desired position, or calculate the actual position of the sun image. The deviation from the expected position, convert the position deviation of the sun spot or the sun image into the correction value of the heliostat rotation;

The heliostat rotation controller is fixed on the target heliostat, and its function is to control the rotation of the heliostat;

Data is exchanged between the computing unit and the heliostat rotation controller in a wired or wireless form, and data exchange is performed between the heliostat rotation controller and the light spot sensor in a wired or wireless form ;

The heliostat optical path closed-loop control system is classified into a reflective type and a direct type according to the different working modes of the spot sensor.
The heliostat optical path closed-loop control system according to claim 1, wherein the receiving surface of the spot sensor in the reflective heliostat optical path closed-loop control system faces the target heliostat reflective surface, and is used for receiving the heliostat passing through the heliostat. For the sunlight reflected by the reflecting surface, the angle δ between the normal of the receiving surface and the normal of the reflecting surface of the target heliostat is in the range of 90°<δ≤180°; the sunlight is reflected and irradiated to the target area, part of which is sensed by the light spot The receiving surface of the heliostat receives and forms a sun spot; the actual position of the sun spot can be described by the geometric center or energy distribution centroid of the sun spot, which represents the actual reflected light direction of the target heliostat; the closed-loop control system of the reflective heliostat optical path passes The spot sensor senses the actual reflected light direction of the target heliostat, and according to the deviation from the expected reflected light direction, the heliostat posture is corrected in real time to realize the real-time closed-loop control of the heliostat.

The receiving surface of the spot sensor in the closed-loop control system of the optical path of the direct heliostat is in the same direction as the reflective surface of the target heliostat, and the angle δ between the normal of the receiving surface and the normal of the reflective surface of the target heliostat is in the range of 0°≤δ <90°; part of the sunlight is received by the receiving surface of the spot sensor to form a sun image, and the rest of the sunlight is reflected to the target area through the heliostat reflective surface; the actual position of the sun image can pass through the geometric center of the sun image or the center of mass of energy distribution description, which represents the actual incident light direction of the target heliostat; the direct-type heliostat optical path closed-loop control system senses the actual incident light direction of the target heliostat through the spot sensor, and according to its deviation from the expected incident light direction, The posture of the heliostat is corrected in real time to realize the real-time closed-loop control of the heliostat.
The heliostat optical path closed-loop control system according to claim 1, wherein the light spot sensor in the reflective heliostat optical path closed-loop control system is composed of an image acquisition array composed of at least one image acquisition device; The collector is composed of an imaging optical path, a light intensity attenuation device and an image sensor; the sunlight is reflected by the reflective surface of the heliostat to the image surface of the image acquisition array to form a sun spot; the lens of the image collector faces the reflective surface of the heliostat, and the image captures The number of the heliostats is determined according to the size of the reflecting surface of the heliostat, so that the field of view formed by the image acquisition array can cover the area of the reflecting surface of the heliostat.
The heliostat optical path closed-loop control system according to claim 1, wherein the light spot sensor in the reflective heliostat optical path closed-loop control system is composed of an array composed of photoelectric sensors and a diaphragm; the receiving surface of the photoelectric sensor is Facing the reflective surface of the heliostat, the number of the photoelectric sensors is determined according to the reflection range of the reflective surface of the heliostat, so that the receiving surface composed of the photoelectric sensor array can cover the sunlight reflected by the reflective surface area of the heliostat; The mirror reflection surface is reflected to the receiving surface of the photoelectric sensor array to obtain the electric signal intensity distribution on the receiving surface generated by the solar light spot; the diaphragm is used to limit the range of sunlight irradiated to the light spot sensor so as to form the solar light spot.
The heliostat optical path closed-loop control system according to claim 1, wherein the light spot sensor in the reflective heliostat optical path closed-loop control system is composed of an array of photoelectric sensors and a standard plane mirror; the standard plane The mirror is installed on the target heliostat and rotates synchronously with the rotation of the heliostat reflective surface. The size of the standard plane mirror is determined by the size of the photoelectric sensor and the distance between the photoelectric sensors. The reflective surface of the standard plane mirror and the heliostat reflective surface are determined. The same direction and fixed relative position; the receiving surface of the photoelectric sensor faces the reflective surface of the standard flat mirror, and the number of photoelectric sensors is determined according to the reflection range of the standard flat mirror, so that the receiving surface composed of the photoelectric sensor array can cover the standard flat mirror. The sun spot reflected by the plane mirror; the sunlight is reflected to the receiving surface of the photoelectric sensor array through the reflective surface of the standard plane mirror, and the electric signal intensity distribution of the receiving surface generated by the sun spot is obtained.
The heliostat optical path closed-loop control system according to claim 1, wherein the light spot sensor in the reflective heliostat optical path closed-loop control system is an image acquisition array composed of a receiving board and at least one image acquisition device and a standard The image collector is composed of an imaging optical path and an image sensor; the receiving surface of the receiving plate is a diffuse reflection surface, and the receiving surface faces the reflective surface of the standard flat mirror, and is used to receive the reflected surface of the standard flat mirror. Sunlight; the size of the receiving plate covers the reflection range of the standard plane reflector; the standard plane reflector is installed on the target heliostat and rotates synchronously with the rotation of the heliostat reflective surface; the size of the standard plane reflector is determined by The resolution of the image acquisition array is determined, the reflective surface of the standard plane mirror and the reflective surface of the heliostat are in the same direction and the relative positions are fixed; the lens in the image acquisition array faces the receiving surface of the receiving plate, and the number of image collectors is determined according to the size of the receiving plate, It is used to identify the actual position of the sun spot on the receiving plate, so that the field of view composed of the image acquisition array can cover the receiving plate area.
The heliostat optical path closed-loop control system according to claim 1, wherein the light spot sensor in the direct-illuminated heliostat optical path closed-loop control system is composed of an image acquisition array composed of at least one image acquisition device; The collector is composed of an imaging optical path, a light intensity attenuation device and an image sensor; the field of view formed by the image acquisition array covers the moving range of the sun relative to the target heliostat; the lens of the image collector is directed in the same direction as the reflection surface of the heliostat To directly collect the sun image, it is used to identify the relative position of the sun image in the field of view of the image acquisition array.
A heliostat optical path closed-loop control method, characterized in that the steps are as follows:

(1) At time ti, the spot sensor collects the sun spot or solar image distribution information, and the computing unit calculates the actual position [u ti ,v ti ] n of the sun spot or solar image based on the solar spot or solar image distribution information, where ti represents The i-th time point in a single working day, n represents the number of the heliostat, u ti represents the value of the u-axis direction of the actual position of the sun spot or sun image at time ti , and v ti represents the v of the actual position of the sun spot or sun image at time ti axis direction value;

(2) The calculation unit calculates the desired position information [Tu ti , Tv ti ] of the sun spot or sun image of the target heliostat at time ti, where Tu ti represents the u-axis direction value of the desired position of the sun spot or sun image at time ti , and Tv ti represents The value of the v-axis direction of the desired position of the sun spot or sun image at time ti;

(3) The calculation unit calculates the sun spot or sun image position deviation of the target heliostat [Δu ti ,Δv ti ] n =[Tu ti -u ti ,Tv ti -v ti ] n , Δu ti represents the sun spot or the sun spot at time ti The relative deviation between the expected coordinates and the actual coordinates in the u-axis direction of the sun image, Δv ti represents the relative deviation between the expected coordinates and the actual coordinates in the v-axis direction of the sun spot or the sun image at time ti;

(4) The heliostat rotation about at least two axes to achieve the function of reflected sunlight to the target area, the target calculation unit time ti heliostat sun or sun spot image position deviation mode according to the rotation of the heliostat [[Delta] u ti ,Δv ti ] n is converted into the rotational deviation value of the heliostat;

(5) The heliostat rotation controller corrects the target heliostat attitude at time ti in real time according to the rotation deviation value, so that the actual position [u ti , v ti ] n of the sun spot or sun image is constantly approaching or overlapping the desired position [Tu ti ] , Tv ti ];

(6) In a single working day, repeat steps (1)-(5), the calculation unit uses the deviation between the actual position of the sun spot or the sun image and the expected position as feedback, and continuously corrects the posture of the target heliostat in real time, so that at any time The actual position of the sun spot or sun image fluctuates near the desired position, realizing the closed-loop control of the light path of the heliostat to ensure that the reflected light of the heliostat can be correctly irradiated to the target area.
The closed-loop control method of the heliostat optical path according to claim 8, wherein in the step (4), the first rotation mode of the heliostat is: The Y-axis rotates, the position of the Y-axis remains unchanged, and the X-axis rotates around the Y-axis with the reflection surface of the heliostat; the rotation deviation value:

In the formula: u 1/2 represents the u-axis coordinate of the center of the receiving surface, v 1/2 represents the v-axis coordinate of the receiving surface center, d represents the distance from the receiving surface to the heliostat reflective surface,
represents the rotational deviation of the X-axis,
Indicates the Y-axis rotation deviation;

Heliostat rotation mode 2: The heliostat reflective surface rotates around two mutually orthogonal rotation axes, Y-axis and Z-axis, where the position of the Z-axis remains unchanged, and the Y-axis rotates around the Z-axis with the heliostat reflective surface; rotation deviation Value:

where:
Indicates the Z-axis rotational deviation.
The heliostat optical path closed-loop control method according to claim 8, wherein in the step (1), the calculation unit calculates the desired position of the target heliostat sun spot or sun image as follows:

(1) The calculation unit is based on the center coordinates of the target heliostat at time ti
Calculate the normalized reflection vector at this moment with the target pointing point [tx n ,ty n ,tz n ]:

where | | represents the modulo operation,
Represents the value of the X-axis direction of the center coordinate of the target heliostat at time ti,
Represents the value of the Y-axis direction of the center coordinate of the target heliostat at time ti,
Represents the value of the Z-axis direction of the center coordinate of the target heliostat at time ti, tx n represents the value of the X-axis direction of the coordinate of the target pointing point at time ti, ty n represents the value of the Y-axis direction of the coordinate of the target pointing point at time ti , and tz n represents the value of the target pointing point at time ti The value of the coordinate Z-axis direction,
represents the X-axis direction component of the normalized reflection vector at time ti,
represents the Y-axis direction component of the normalized reflection vector at time ti,
Represents the Z-axis direction component of the normalized reflection vector at time ti;

(2) The computing unit calculates the normalized sunlight incident vector at time ti
Represents the X-axis direction component of the normalized sunlight incident vector at time ti,
Represents the Y-axis direction component of the normalized sunlight incident vector at time ti,
Represents the Z-axis direction component of the normalized sunlight incident vector at time ti;

(3) The computing unit calculates the normalized normal vector of the reflection surface of the heliostat at this moment:

where:
represents the X-axis direction component of the normalized normal vector of the heliostat reflecting surface at time ti,
represents the Y-axis direction component of the normalized normal vector of the heliostat reflecting surface at time ti,
Represents the Z-axis direction component of the normalized normal vector of the heliostat reflecting surface at time ti;

(4) The angle δ=[δ n δ u δ v ] between the normal vector of the receiving surface of the spot sensor and the normal vector of the heliostat reflective surface, where δ n represents the distance around the normal vector of the heliostat reflective surface Deviation angle, δ u represents the deviation angle around the u-axis, and δ v represents the deviation angle around the v-axis; in the closed-loop control system of the reflective heliostat, the value of δ is in the range of 90°≤δ<180°. The value range of δ in the closed-loop control system is 0°≤δ<90°;

The calculation unit calculates the normal vector of the receiving surface based on the angle δ between the normal vector of the receiving surface of the spot sensor and the normal vector of the reflecting surface of the heliostat:

In the formula: n represents the number of the heliostat, Rot u () represents the rotation matrix around the u-axis, Rot v () represents the rotation matrix around the v-axis, and Rot n () represents the rotation around the normal vector of the heliostat reflecting surface matrix,
Represents the X-axis direction component of the normalized normal vector of the receiving surface of the spot sensor at time ti,
Represents the Y-axis direction component of the normalized normal vector of the receiving surface of the spot sensor at time ti,
Represents the Z-axis direction component of the normalized normal vector of the receiving surface of the spot sensor at time ti;

(5) In the closed-loop control system of the reflective heliostat, the calculation unit receives the center coordinates of the receiving surface according to the time ti
and the receiving surface normal vector
Establish the three-dimensional equation of the receiving surface, and then according to the sunlight reflection vector at time ti
and heliostat center coordinates
Establish a three-dimensional linear equation system based on the reflecting surface of the heliostat, and solve the coordinates of the intersection point between the reflected light and the receiving surface
where k represents the K-th intersection; finally, the coordinates of the intersection are converted to the coordinate system of the receiving surface to obtain the desired position coordinates of the sun spot [Tu ti , Tv ti ];

In the closed-loop control system of the direct-illuminated heliostat, the calculation unit receives the center coordinates of the surface according to the time ti
and the receiving surface normal vector
Establish the three-dimensional equation of the receiving surface, and then according to the incident vector of sunlight at time ti
and heliostat center coordinates
Establish a three-dimensional straight line equation system based on the reflecting surface of the heliostat, and solve the coordinates of the intersection of the incident light pointing and the receiving surface
Where k represents the K-th intersection, and finally the coordinates of the intersection are converted to the coordinate system of the receiving surface to obtain the desired coordinates of the sun image [Tu ti , Tv ti ].