Heliostat light path closed-loop control system and method
阅读说明：本技术 一种定日镜光路闭环控制系统及方法 (Heliostat light path closed-loop control system and method ) 是由 陈煜达 陈昊 孙楠 沈平 于 2020-07-07 设计创作，主要内容包括：本发明公开了一种定日镜光路闭环控制系统及方法,包括光斑感应器、定日镜转动控制器和计算单元；所述光斑感应器固定在定日镜上,随目标定日镜反射面转动而同步转动；所述计算单元用于计算太阳光斑实际位置与期望位置的偏差或者计算太阳像实际位置与期望位置的偏差；所述定日镜转动控制器固定在目标定日镜上；所述计算单元与所述定日镜转动控制器之间、所述定日镜转动控制器与所述光斑感应器之间进行数据交换。本发明利用光路反射原理通过控制入射光指向或反射光指向实现定日镜姿态的实时控制,有效解决了开环控制方式中不能基于光路反馈实时修正定日镜姿态的问题,实现了一种高精度、高效率的、实时的定日镜光路闭环控制系统。(The invention discloses a heliostat light path closed-loop control system and a heliostat light path closed-loop control method, wherein the heliostat light path closed-loop control system comprises a light spot sensor, a heliostat rotation controller and a calculation unit; the light spot sensor is fixed on the heliostat and synchronously rotates along with the rotation of the reflecting surface of the target heliostat; the calculating unit is used for calculating the deviation between the actual position of the solar facula and the expected position or calculating the deviation between the actual position of the solar image and the expected position; the heliostat rotation controller is fixed on a target heliostat; and data exchange is carried out between the computing unit and the heliostat rotation controller and between the heliostat rotation controller and the light spot sensor. The heliostat attitude real-time control method realizes real-time control of the attitude of the heliostat by controlling the direction of incident light or the direction of reflected light by utilizing the principle of light path reflection, effectively solves the problem that the attitude of the heliostat cannot be corrected in real time based on light path feedback in an open-loop control mode, and realizes a high-precision, high-efficiency and real-time heliostat light path closed-loop control system.)
1. A heliostat light path closed-loop control system, comprising: the device comprises a light spot sensor, a heliostat rotation controller and a computing unit; the light spot sensor is fixed on the heliostat and synchronously rotates along with the rotation of the reflecting surface of the target heliostat;
the computing unit is used for computing the actual position of a solar light spot or a solar image of a target heliostat, computing the expected position of the solar light spot or the solar image of the target heliostat, computing the deviation between the actual position of the solar light spot and the expected position or the deviation between the actual position of the solar image and the expected position, and converting the deviation of the solar light spot or the solar image position into a heliostat rotation correction value;
the heliostat rotation controller is fixed on a target heliostat and has the function of controlling the rotation of the heliostat;
data exchange is carried out between the computing unit and the heliostat rotation controller in a wired or wireless mode, and data exchange is carried out between the heliostat rotation controller and the light spot sensor in a wired or wireless mode;
the heliostat light path closed-loop control system is divided into a reflection type and a direct injection type according to different working modes of the light spot sensor.
2. A heliostat light path closed-loop control system of claim 1, wherein: the receiving surface of the light spot sensor in the reflective heliostat light path closed-loop control system faces to the reflecting surface of a target heliostat and is used for receiving the solar rays reflected by the reflecting surface of the heliostat, and the included angle between the normal of the receiving surface and the normal of the reflecting surface of the target heliostat ranges from 90 degrees to less than or equal to 180 degrees; the sunlight is reflected and then irradiates to a target area, and a part of the sunlight is received by a receiving surface of the light spot sensor to form a solar light spot; the actual position of the solar spot can be described by the geometric center or the energy distribution centroid of the solar spot, and the actual reflected light direction of the target heliostat is represented; the reflection type heliostat light path closed-loop control system senses the actual reflected light direction of a target heliostat through a light spot sensor, and corrects the posture of the heliostat in real time according to the deviation of the actual reflected light direction and the expected reflected light direction, so that the real-time light path closed-loop control of the heliostat is realized;
the receiving surface of a light spot sensor in the direct-projection heliostat light path closed-loop control system is in the same direction as the reflecting surface of a target heliostat, and the value range of the included angle between the normal of the receiving surface and the normal of the reflecting surface of the target heliostat is more than or equal to 0 degree and less than 90 degrees; a part of sunlight is received by a receiving surface of the light spot sensor to form a sun image, and the rest of sunlight is reflected to a target area through a reflecting surface of the heliostat; the actual position of the sun image can be described by the geometric center or energy distribution centroid of the sun image, which characterizes the actual incident light pointing direction of the target heliostat; the direct-injection heliostat light path closed-loop control system senses the actual incident light direction of a target heliostat through a light spot sensor, and corrects the posture of the heliostat in real time according to the deviation of the actual incident light direction and the expected incident light direction, so that the real-time light path closed-loop control of the heliostat is realized.
3. A heliostat light path closed-loop control system of claim 1, wherein: the light spot sensor in the reflective heliostat light path closed-loop control system is composed of an image acquisition array consisting of at least one image collector; the image collector consists of an imaging light path, a light intensity attenuation device and an image sensor; sunlight is reflected to an image surface of the image acquisition array through a heliostat reflecting surface to form a solar facula; the lens of the image collector faces to the heliostat reflecting surface, and the number of the image collectors is determined according to the size of the heliostat reflecting surface, so that the field of view formed by the image collecting array can cover the heliostat reflecting surface area.
4. A heliostat light path closed-loop control system of claim 1, wherein: the light spot sensor in the reflective heliostat light path closed-loop control system is composed of an array consisting of photoelectric sensors and a diaphragm; the receiving surface of the photoelectric sensor faces to the reflecting surface of the heliostat, and the number of the photoelectric sensors is determined according to the reflecting range of the reflecting surface of the heliostat, so that the receiving surface formed by the photoelectric sensor array can cover the solar rays reflected by the reflecting surface area of the heliostat; the sun light is reflected to a receiving surface of the photoelectric sensor array through a reflecting surface of the heliostat, and the intensity distribution of receiving surface electric signals generated by solar facula is obtained; the diaphragm is used for limiting the range of sunlight irradiating the facula sensor so as to form the solar facula.
5. A heliostat light path closed-loop control system of claim 1, wherein: the light spot sensor in the reflective heliostat light path closed-loop control system consists of an array consisting of photoelectric sensors and a standard plane reflector; the standard plane reflecting mirror is arranged on a target heliostat and synchronously rotates along with the rotation of the reflecting surface of the heliostat, the size of the standard plane reflecting mirror is determined by the size of a photoelectric sensor and the distance between the photoelectric sensors, and the reflecting surface of the standard plane reflecting mirror and the reflecting surface of the heliostat are in the same direction and the relative position is fixed; the receiving surface of the photoelectric sensor faces to the reflecting surface of the standard plane reflecting mirror, and the number of the photoelectric sensors is determined according to the reflecting range of the standard plane reflecting mirror, so that the receiving surface formed by the photoelectric sensor array can cover solar faculae reflected by the standard plane reflecting mirror; sunlight is reflected to a receiving surface of the photoelectric sensor array through a reflecting surface of the standard plane reflector, and intensity distribution of receiving surface electric signals generated by solar faculae is obtained.
6. A heliostat light path closed-loop control system of claim 1, wherein: the light spot sensor in the reflective heliostat light path closed-loop control system consists of an image acquisition array and a standard plane reflector, wherein the image acquisition array consists of a receiving plate and at least one image collector; the image collector consists of an imaging light path and an image sensor; the receiving surface of the receiving plate is a diffuse reflection surface, faces to the reflection surface of the standard plane reflector and is used for receiving sunlight reflected by the reflection surface of the standard plane reflector; the size of the receiving plate covers the reflection range of the standard plane reflector; the standard plane reflecting mirror is arranged on a target heliostat and synchronously rotates along with the rotation of the reflecting surface of the heliostat; the size of the standard plane reflector is determined by the resolution of the image acquisition array, and the reflecting surface of the standard plane reflector and the reflecting surface of the heliostat are in the same direction and have fixed relative positions; the lens in the image acquisition array faces to the receiving surface of the receiving plate, the number of the image collectors is determined according to the size of the receiving plate, and the image collectors are used for identifying the actual position of the solar facula on the receiving plate, so that the field of view formed by the image acquisition array can cover the area of the receiving plate.
7. A heliostat light path closed-loop control system of claim 1, wherein: the light spot sensor in the direct-injection heliostat light path closed-loop control system is composed of an image acquisition array consisting of at least one image collector; the image collector consists of an imaging light 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 points to the same direction as the reflection surface of the heliostat, and directly collects a sun image for identifying the relative position of the sun image in the image collection array view field.
8. A closed-loop control method for a heliostat light path is characterized by comprising the following steps:
(1) the light spot sensor at the moment ti collects the distribution information of the solar light spots or the solar images, and the calculating unit calculates the actual positions [ u ] of the solar light spots or the solar images based on the distribution information of the solar light spots or the solar imagesti,vti]nWhere ti denotes the ith time point within a single working day, n denotes the heliostat number, utiU-axis direction value, v, representing the actual position of the solar spot or image at time titiA v-axis direction numerical value representing the actual position of the solar facula or the solar image at the time ti;
(2) the calculating unit calculates expected position information [ Tu ] of the sun spot or the sun image of the target heliostat at the time titi,Tvti]，TutiU-axis direction value, Tv, representing the desired position of the solar spot or image at time titiA v-axis direction numerical value representing the expected position of the solar facula or the solar image at the moment ti;
(3) the calculating unit calculates the position deviation [ delta u ] of the solar facula or the solar image of the target heliostatti,Δvti]n＝[Tuti-uti,Tvti-vti]n，ΔutiRepresents the relative deviation delta v between the expected coordinate and the actual coordinate in the u-axis direction of the solar facula or the solar image at the time titiIndicating sun spot or sun spot at time tiThe relative deviation of the expected coordinate and the actual coordinate in the direction of the positive image v axis;
(4) the heliostat rotates around at least two axes to realize the function of reflecting sunlight to a target area, and the computing unit deviates the solar faculae or the solar image position of the target heliostat at the moment ti according to the rotation mode of the heliostatti,Δvti]nConverting the rotation deviation value of the heliostat;
(5) the heliostat rotation controller corrects the attitude of the target heliostat at the moment ti in real time according to the rotation deviation value, so that the actual position [ u ] of the solar facula or the solar imageti,vti]nContinuously approaching or coinciding with the desired position [ Tuti,Tvti]；
(6) And (3) repeating the steps (1) to (5) within a single working day, and continuously correcting the attitude of the target heliostat in real time by using the deviation between the actual position and the expected position of the solar facula or the solar image as feedback by the calculation unit, so that the actual position of the solar facula or the solar image fluctuates near the expected position at any moment, closed-loop control of a light path of the heliostat is realized, and the reflected light of the heliostat can be correctly irradiated to a target area.
9. The heliostat light path closed-loop control method according to claim 8, wherein in the step (4), the rotation modes of the heliostat are as follows: the heliostat reflecting surface rotates around an X axis and a Y axis of two mutually orthogonal rotating shafts, wherein the position of the Y axis is kept unchanged, and the X axis rotates around the Y axis along with the heliostat reflecting surface; rotational deviation values:
in the formula: u. of1/2Showing the u-axis directional coordinate of the center of the receiving surface, v1/2The coordinate of the v-axis direction of the center of the receiving surface is shown, d represents the distance from the receiving surface to the reflecting surface of the heliostat,the deviation of the rotation of the X-axis is shown,represents the Y-axis rotation deviation;
a heliostat rotation mode II: the heliostat reflecting surface rotates around two mutually orthogonal rotating shafts, namely a Y axis and a Z axis, wherein the position of the Z axis is kept unchanged, and the Y axis rotates around the Z axis along with the heliostat reflecting surface; rotational deviation values:
in the formula:indicating Z-axis rotational misalignment.
10. The heliostat light path closed-loop control method of claim 8, wherein in step (1), the step of calculating the target heliostat solar spot or image desired position by the calculating unit is as follows:
(1) the computing unit is used for calculating the central coordinates of the target heliostat according to the ti moment
where | | represents a modulo operation,representing the X-axis direction value of the central coordinate of the target heliostat at the time ti,
(2) the computing unit computes the normalized sunlight incident vector at the time ti
(3) the calculation unit calculates the normalized normal vector of the reflecting surface of the heliostat at the moment:
in the formula:
(4) the angle between the normal vector of the receiving surface of the facula sensor and the normal vector of the reflecting surface of the heliostat is [ solution ]n u v]In the formulanRepresenting the deviation angle around the normal vector of the reflecting surface of the heliostat,uindicating the angle of deviation about the u-axis,vrepresenting the angle of deviation about the v-axis; the value taking range of the reflective heliostat closed-loop control system is more than or equal to 90 degrees and less than 180 degrees, and the value taking range of the direct-injection heliostat closed-loop control system is more than or equal to 0 degrees and less than 90 degrees;
the calculation unit calculates a receiving surface normal vector based on an included angle between the receiving surface normal vector of the light spot sensor and the heliostat reflecting surface normal vector:
in the formula: n denotes heliostat number, Rotu() Representing a rotation matrix about the u-axis, Rotv() Representing a rotation matrix about the v-axis, Rotn() A rotation matrix representing the rotation of the heliostat reflecting surface normal vector around,
(5) in the closed-loop control system of the reflecting heliostat, a calculation unit receives the central coordinate of a surface according to the ti momentAnd receiving surface normal vector
In the closed-loop control system of the direct-injection heliostat, a calculation unit receives the central coordinate of a surface according to the ti momentAnd receiving surface normal vector
Technical Field
The invention belongs to the technical field of solar photo-thermal power generation, and particularly relates to a closed-loop control system and method for a light path of a heliostat in tower-type solar energy.
Background
As a core component of a tower-type solar photo-thermal power plant, a heliostat functions to reflect sunlight irradiated to its surface to a target heat absorber region. Because the sun changes position constantly with time, the heliostat needs to have enough control precision to ensure that the pointing precision of the reflected light meets the design requirement, namely, the sunlight reflected by the heliostat can continuously and accurately irradiate the target heat absorber area, thereby ensuring the concentration efficiency of the sunlight energy of the heat absorber area and the working efficiency of the solar photo-thermal power station.
The existing heliostat control mode is based on open-loop control, and the core of the control mode is a motion model of the heliostat. The method comprises the steps of obtaining a heliostat motion model through iterative correction by calibrating a white board, an image collector and the like, estimating operation information required by the heliostat according to a calculation result of the sun position and the heliostat motion model, namely generating an operation table comprising time and a rotation angle, and finally controlling the rotation of the heliostat according to the operation table by a heliostat transmission control mechanism.
The open-loop control method of the heliostat has the following problems: 1) a long debugging time is required. The open-loop control method depends on a heliostat motion model, and the control precision is ensured by correcting the motion model. The conventional motion model correction method is a calibration white board method, namely, solar light spots of a target heliostat are reflected to a target calibration white board area at different time periods, an image is analyzed by an image acquisition system to determine the actual position of the center of the reflected light spots, and finally a motion model of the target heliostat is solved based on time information and the center position of the reflected light spots. The other heliostat motion model correction method is that an image acquisition system which rotates along with the rotation of the heliostat is arranged on the heliostat, the image acquisition system takes the sun or other celestial bodies with certain brightness as a target, and a motion model of the target heliostat is solved based on the deviation of the position of the target center on an image plane and the center of the image plane. No matter what heliostat motion model is adopted for correction, the motion model needs to be continuously subjected to iterative correction in a long debugging time. Only when the precision of the corrected motion model meets the design requirement, the estimated deviation between the heliostat operation information and the actual operation condition can meet the design requirement, and the precision of open-loop control of the heliostat can be effectively guaranteed. 2) No real-time feedback is available. The existing open-loop control method relies on a motion model to estimate operation information of the heliostat and carries out unidirectional control on the heliostat based on sequential action, namely the heliostat only rotates according to an estimated operation table in the actual rotation process, the accuracy of the actual posture of the heliostat cannot be fed back, and the automatic deviation rectifying capability is not provided. Because the motion model is an abstract induction of the actual operation condition of the heliostat, the obtained estimated result is only close to the actual condition and cannot completely represent the actual condition, and the attitude of the heliostat controlled based on the motion model has certain deviation from the actual target attitude. Due to the fact that real-time feedback is not available, the heliostat cannot process some abnormal conditions, such as the existence of non-ideality, which cannot be corrected by a model, in a partial region of a travel range, the change of a surface shape caused by wind and the like. 3) The performance index requirement of the mechanical transmission mechanism is high. In order to ensure the accuracy and stability of open-loop control, the mechanical transmission mechanism of the heliostat needs to have higher performance index requirements, including repeatability accuracy requirements, rotation consistency requirements and the like. If the performance index is poor, namely performance parameters such as repeatability precision, rotation consistency and the like are poor, the rotation of the heliostat can show no obvious regularity, so that the actual rotation condition of the heliostat cannot be accurately described by the motion model, and the attitude of the heliostat in an open-loop control state is uncontrollable. This also affects the efficiency of the concentration of solar energy in the heat absorber area, even because the reflected light is directed uncontrollably, creating a safety hazard.
Therefore, a high-precision and high-efficiency heliostat light path closed-loop control system is needed, which can accurately correct the real-time attitude of the heliostat, so that the reflected solar facula can accurately irradiate the target area, and the convergence efficiency of the solar energy of the heat collector area and the photo-thermal conversion efficiency of the solar photo-thermal power station are ensured.
Disclosure of Invention
In order to solve the problems, the invention aims at the characteristic of high control precision requirement of the heliostat in the tower type solar photo-thermal power generation technology, utilizes the light path reflection principle to realize the real-time control of the attitude of the heliostat by controlling the direction of incident light or the direction of reflected light, effectively solves the problem that the attitude of the heliostat cannot be corrected in real time based on light path feedback in an open-loop control mode, and realizes a high-precision, high-efficiency and real-time heliostat light path closed-loop control system.
The invention discloses a heliostat light path closed-loop control system, which comprises: the device comprises a light spot sensor, a heliostat rotation controller and a computing unit. The light spot sensor is fixed on the heliostat and synchronously rotates along with the rotation of the reflecting surface of the target heliostat. The calculating unit is used for calculating the actual position of a solar light spot or a solar image of a target heliostat, calculating the expected position of the solar light spot or the solar image of the target heliostat, calculating the deviation between the actual position of the solar light spot and the expected position or calculating the deviation between the actual position of the solar image and the expected position, and converting the deviation of the solar light spot or the solar image position into a heliostat rotation correction value. The heliostat rotation controller is fixed on a target heliostat and has the function of controlling the rotation of the heliostat. And the computing unit and the heliostat rotation controller exchange data in a wired or wireless mode, and the heliostat rotation controller and the light spot sensor exchange data in a wired or wireless mode.
The heliostat light path closed-loop control system is divided into a reflection type and a direct injection type according to different working modes of the light spot sensor. The reflection type principle is that reflected light direction information of a target heliostat at the moment is obtained by sensing the actual position of a solar facula; the direct projection type principle is that the incident light direction information of the target heliostat at the moment is obtained by sensing the actual position of the sun image.
The receiving surface of the light spot sensor in the reflective heliostat light path closed-loop control system faces to the reflecting surface of a target heliostat and is used for receiving solar light spots reflected by the reflecting surface of the heliostat, and the included angle between the normal of the receiving surface and the normal of the reflecting surface of the target heliostat is less than or equal to 180 degrees. Sunlight irradiates to a target area after being reflected, wherein a part of the sunlight is received by a receiving surface of the light spot sensor to form a solar light spot; the actual position of the solar spot may be described by the geometric center or energy distribution centroid of the solar spot, which characterizes the actual reflected light pointing direction of the target heliostat. The reflection type light path closed-loop control system senses the actual reflected light direction of a target heliostat through the light spot sensor, and corrects the posture of the heliostat in real time according to the deviation of the actual reflected light direction and the expected reflected light direction, so that the real-time light path closed-loop control of the heliostat is realized.
The receiving surface of the light spot sensor in the direct-projection heliostat light path closed-loop control system is in the same direction (simultaneously faces to the sun) with the reflecting surface of a target heliostat, and the value range of the included angle between the normal of the receiving surface and the normal of the reflecting surface of the target heliostat is not less than 0 degree and not more than 90 degrees. A part of sunlight is received by a receiving surface of the light spot sensor to form a sun image, and the rest of sunlight is reflected to a target area through a reflecting surface of the heliostat; the actual position of the sun image can be described by the geometric center or energy distribution centroid of the sun image, which characterizes the actual incident light pointing direction of the target heliostat. The direct-injection type light path closed-loop control system senses the actual incident light direction of a target heliostat through a light spot sensor, and corrects the posture of the heliostat in real time according to the deviation of the actual incident light direction and the expected incident light direction, so that the real-time light path closed-loop control of the heliostat is realized.
The working process of the heliostat light path closed-loop control system comprises the following steps:
(1) the light spot sensor at the moment ti collects the distribution information of the solar light spots or the solar images, and the calculating unit calculates the actual positions [ u ] of the solar light spots or the solar images based on the distribution information of the solar light spots or the solar imagesti,vti]nWhere ti denotes the ith time point within a single working day, n denotes the heliostat number, utiU-axis direction value, v, representing the actual position of the solar spot or image at time titiA v-axis direction numerical value representing the actual position of the solar facula or the solar image at the time ti;
(2) the calculating unit calculates expected position information [ Tu ] of the sun spot or the sun image of the target heliostat at the time titi,Tvti]，TutiU-axis direction value, Tv, representing the desired position of the solar spot or image at time titiA v-axis direction numerical value representing the expected position of the solar facula or the solar image at the moment ti;
(3) the computing unit computes the sun light spot or the sun image position of the target heliostatOffset [ Delta u ]ti,Δvti]n＝[Tuti-uti,Tvti-vti]n，ΔutiRepresents the relative deviation delta v between the expected coordinate and the actual coordinate in the u-axis direction of the solar facula or the solar image at the time titiRepresenting the relative deviation of the expected coordinate and the actual coordinate of the solar facula or the solar image in the v-axis direction at the moment ti;
(4) the heliostat rotates around at least two axes to realize the function of reflecting sunlight to a target area, and the computing unit deviates the solar faculae or the solar image position of the target heliostat at the moment ti according to the rotation mode of the heliostatti,Δvti]nAnd converting the rotation deviation value of the heliostat.
According to the first rotation mode of the heliostat, the reflection surface of the heliostat rotates around the X axis and the Y axis of two mutually orthogonal rotation shafts, wherein the position of the Y axis is kept unchanged, and the X axis rotates around the Y axis along with the reflection surface of the heliostat. Rotational deviation values:
in the formula: u. of1/2Showing the u-axis directional coordinate of the center of the receiving surface, v1/2The coordinate of the v-axis direction of the center of the receiving surface is shown, d represents the distance from the receiving surface to the reflecting surface of the heliostat,
In the second rotation mode of the heliostat of the invention, the mirror surface of the heliostat rotates around the Y axis and the Z axis of two mutually orthogonal rotating shafts,
wherein the position of the Z axis is kept unchanged, and the Y axis rotates around the Z axis along with the reflecting surface of the heliostat. Rotational deviation values:
in the formula:indicating Z-axis rotational misalignment.
(5) The heliostat rotation controller corrects the attitude of the target heliostat at the moment ti in real time according to the rotation deviation value, so that the actual position [ u ] of the solar facula or the solar imageti,vti]nContinuously approaching or coinciding with the desired position [ Tuti,Tvti](ii) a (6) And (3) repeating the steps (1) to (5) within a single working day, and continuously correcting the attitude of the target heliostat in real time by using the deviation of the actual position of the solar facula or the solar image and the expected position as feedback by the calculation unit, so that the actual position of the solar facula or the solar image fluctuates near the expected position at any moment, closed-loop control of a light path of the heliostat is realized, and the reflected light direction of the heliostat can be correctly irradiated to a target area.
The method for calculating the expected position of the solar facula or the solar image of the target heliostat by the calculating unit in the heliostat closed-loop control system comprises the following steps:
(1) the computing unit is used for calculating the central coordinates of the target heliostat according to the ti moment
where | | represents a modulo operation,
(2) the computing unit computes the normalized sunlight incident vector at the time ti
(3) the calculation unit calculates the normalized normal vector of the reflecting surface of the heliostat at the moment:
in the formula:representing the X-axis direction component of the normalized normal vector of the heliostat reflecting surface at time ti,
(4) included angle between normal vector of receiving surface of facula sensor and normal vector of reflecting surface of heliostat
＝[n u v]In the formulanRepresenting the deviation angle around the normal vector of the reflecting surface of the heliostat,uindicating the angle of deviation about the u-axis,vrepresenting the angle of deviation about the v-axis; the value taking range of the reflective heliostat closed-loop control system is more than or equal to 90 degrees and less than 180 degrees, and the value taking range of the direct-injection heliostat closed-loop control system is more than or equal to 0 degrees and less than 90 degrees;
the calculation unit calculates a receiving surface normal vector based on an included angle between the receiving surface normal vector of the light spot sensor and the heliostat reflecting surface normal vector:
in the formula: n denotes heliostat number, Rotu() Representing a rotation matrix about the u-axis, Rotv() Representing a rotation matrix about the v-axis, Rotn() A rotation matrix representing the rotation of the heliostat reflecting surface normal vector around,
(5) in the closed-loop control system of the reflecting heliostat, a calculation unit receives the central coordinate of a surface according to the ti momentAnd receiving surface normal vectorEstablishing a three-dimensional equation of the receiving surface and then according to the sunlight reflection vector at the time tiAnd heliostat center coordinatesEstablishing a three-dimensional linear equation set based on the heliostat mirror surface, and solving the intersection point coordinate of the reflected light direction and the receiving surfaceWherein K represents the Kth intersection point; finally, converting the intersection point coordinate into a receiving surface coordinate system to obtain the expected position coordinate [ Tu ] of the solar faculati,Tvti]。
In the closed-loop control system of the direct-injection heliostat, a calculation unit receives the central coordinate of a surface according to the ti moment
In the invention, the light spot sensor in the reflective light path closed-loop control system is composed of an image acquisition array consisting of at least one image collector, and the image collector consists of an imaging light path (a lens or a pinhole, etc.), a light intensity attenuating device and an image sensor. Sunlight is reflected to the image surface of the image acquisition array through the reflecting surface of the heliostat to form a solar facula. The lens of the image collector faces to the heliostat reflecting surface, and the number of the image collectors is determined according to the size of the heliostat reflecting surface, so that the field of view formed by the image collecting array can cover the heliostat reflecting surface area.
The solar light spot actual position identification with the image acquisition array as the light spot sensor comprises the following steps:
(1) the image acquisition array acquires an image of a reflecting surface of the heliostat;
(2) obtaining the area range of the solar facula in each image collector at the moment ti by a binarization method;
(3) calculating the geometric center of the solar facula at the moment based on the solar facula area in the binary image, or calculating the energy distribution centroid of the solar facula at the moment based on the solar facula area in the gray-scale image or the color image, and expressing the image coordinate of the actual position (the geometric center or the energy distribution centroid) of the solar facula asWherein m represents the number of the image collector, n represents the number of the heliostat, and h represents the number of pixels in the u-axis direction of the actual position of the solar facula at the ti momentAnd l represents the number of pixels in the v-axis direction of the actual position of the solar spot at the time ti.
The light spot sensor in the reflective light path closed-loop control system can be composed of an array consisting of photoelectric sensors and a diaphragm. The photoelectric sensor includes a non-imaging sensor based on photoelectric effect, such as a photoresistor, a photodiode, and a photoswitch. The receiving surface of the photoelectric sensor faces to the reflecting surface of the heliostat, and the number of the photoelectric sensors is determined according to the reflecting range of the reflecting surface of the heliostat, so that the receiving surface formed by the photoelectric sensor array can cover solar facula reflected by the reflecting surface area of the heliostat. Sunlight is reflected to a receiving surface of the photoelectric sensor array through a reflecting surface of the heliostat, and intensity distribution of receiving surface electric signals generated by solar facula is obtained. The diaphragm is used for limiting the range of sunlight irradiating the facula sensor so as to form the solar facula.
The light spot sensor in the reflective light path closed-loop control system can be composed of an array formed by photoelectric sensors and a standard plane mirror. The photoelectric sensor includes a non-imaging sensor based on photoelectric effect, such as a photoresistor, a photodiode, and a photoswitch. The standard plane reflecting mirror is arranged on a target heliostat and synchronously rotates along with the rotation of the heliostat mirror surface, the size of the standard plane reflecting mirror is determined by the size of a photoelectric sensor and the distance between the photoelectric sensors, and the reflecting surface of the standard plane reflecting mirror and the reflecting surface of the heliostat are in the same direction (face the sun simultaneously) and the relative position is fixed. The receiving surface of the photoelectric sensor faces the reflecting surface of the standard plane reflecting mirror, and the number of the photoelectric sensors is determined according to the reflecting range of the standard plane reflecting mirror, so that the receiving surface formed by the photoelectric sensor array can cover solar faculae reflected by the standard plane reflecting mirror. Sunlight is reflected to a receiving surface of the photoelectric sensor array through a reflecting surface of the standard plane reflector, and intensity distribution of receiving surface electric signals generated by solar faculae is obtained.
The solar facula actual position identification with the photoelectric sensor array as the facula sensor comprises the following steps:
(1) the photoelectric sensor array acquires the intensity distribution of the electric signals of the receiving surface;
(2) obtaining a photoelectric sensor range irradiated by the solar faculae on the receiving surface of the photoelectric sensor array at the moment ti based on a preset threshold value according to the intensity distribution of the electric signals, namely the lighted photoelectric sensor range;
(3) calculating a geometric center based on the range of the lighted photoelectric sensor or calculating an energy distribution centroid based on the intensity distribution of the electric signal in the range of the lighted photoelectric sensor, and then expressing the actual position (geometric center or energy distribution centroid) coordinate of the solar facula as [ Outi,Ovti]nWherein n represents the heliostat number, Ou represents the u-axis direction numerical value of the photoelectric sensor array at the actual position of the solar facula at the ti moment, and Ov represents the v-axis direction numerical value of the photoelectric sensor array at the actual position of the solar facula at the ti moment.
The light spot sensor in the reflective light path closed-loop control system can be composed of an image acquisition array and a standard plane mirror, wherein the image acquisition array is composed of a receiving plate and at least one image acquisition device. The image collector consists of an imaging light path and an image sensor. The receiving surface of the receiving plate is a diffuse reflection surface, faces to the reflection surface of the standard plane reflector and is used for receiving sunlight reflected by the reflection surface of the standard plane reflector. The size of the receiving plate covers the reflection range of a standard plane mirror. The standard plane reflecting mirror is arranged on the target heliostat and synchronously rotates along with the rotation of the heliostat mirror surface. The size of the standard plane reflector is determined by the resolution of the image acquisition array, and the reflecting surface of the standard plane reflector and the reflecting surface of the heliostat are in the same direction (simultaneously face to the sun) and the relative position is fixed. The lens in the image acquisition array faces the receiving surface of the receiving plate, the number of the image collectors is determined according to the size of the receiving plate, and the image collectors are used for identifying the actual position of the solar facula on the receiving plate, so that the field of view formed by the image acquisition array can cover the area of the receiving plate. The invention discloses a solar facula actual position recognition method by taking a receiving plate, an image acquisition array and a standard plane reflector as a facula sensor, which comprises the following steps:
(1) the receiving plate receives solar faculae reflected by the reflecting surface of the standard plane reflector;
(2) collecting a receiving plate image through an image collector array, and identifying a solar facula area at the time ti through a binarization method;
(3) calculating the geometric center of the solar facula at the moment based on the solar facula area in the binary image or calculating the energy distribution centroid of the solar facula at the moment based on the solar facula area in the gray image or the color image By taking the center of the receiving plate as the origin, and obtaining the actual coordinate [ By ] of the actual position (geometric center or energy distribution centroid) of the solar facula on the receiving plateti,Bxti]nWherein By represents the numerical value of the u-axis direction of the receiving plate at the actual position of the solar facula at the moment ti, and Bx represents the numerical value of the v-axis direction of the receiving plate at the actual position of the solar facula at the moment ti.
In the invention, the light spot sensor in the direct-injection light path closed-loop control system is composed of an image acquisition array consisting of at least one image acquisition device. The image collector consists of an imaging light path (a lens or a pinhole, etc.), a light intensity attenuating device and an image sensor. The field of view formed by the image acquisition array covers the range of movement of the sun relative to the target heliostat. The lens of the image collector points to the same direction as the reflection surface of the heliostat (simultaneously faces the sun), and directly collects a sun image for identifying the relative position of the actual position of the sun image in the image collection array field of view.
The actual position identification of the solar image by taking the image acquisition array as the light spot sensor comprises the following steps:
(1) the image acquisition array acquires an image of the sun;
(2) obtaining the region of the sun image in each image collector at the moment ti by a binarization method;
(3) calculating the geometric center of the solar image at the moment based on the solar image region in the binary image, or calculating the energy distribution centroid of the solar image at the moment based on the solar image region in the gray-scale image or the color image, and expressing the image coordinate of the actual position (geometric center or energy distribution centroid) of the solar image as
The invention has the beneficial effects that:
(1) the invention relates to a light path closed-loop control system, which dynamically corrects the attitude of a heliostat according to the deviation between the actual position and the expected position of a solar facula or a solar image at any moment, and does not need a heliostat motion model and an operation table calculated based on the motion model.
(2) The invention realizes the closed-loop control of the light path of the heliostat by controlling the direction of incident light or the direction of reflected light by utilizing the principle of light path reflection, does not need to correct the motion model of the heliostat within a long debugging time because of not depending on the motion model of the heliostat, can carry out conventional heat collection and power generation work after the installation of the heliostat is finished, and can effectively improve the opening efficiency of the tower-type solar photo-thermal power station.
(3) The invention can realize closed-loop control of the light path of the heliostat, identify the actual position of a solar facula or a solar image based on the facula sensor, and calculate the central position deviation with the expected position, thereby realizing dynamic correction of the posture of the heliostat by taking the central position deviation as feedback, and effectively ensuring the heat collection and power generation efficiency of the heliostat.
(4) The heliostat control method is not based on the heliostat motion model calculation operation table to drive the heliostat to rotate, and the open-loop control precision of the heliostat is ensured without higher performance indexes of a mechanical transmission mechanism. Because the attitude of the heliostat can be corrected in real time according to the actual position of the solar facula or the actual position of the solar image, higher requirements on performance indexes such as the repeatability precision requirement, the rotation consistency requirement and the like of the transmission mechanism are not required, and the manufacturing cost of the mechanical transmission mechanism of the heliostat is effectively reduced.
(5) According to the invention, by implementing light path closed-loop control on the heliostat, the heliostat mirror surface deformation caused by wind vibration, gravity and the like can be corrected, and the adaptability of the heliostat to the environment is effectively improved.
Drawings
FIG. 1 is a schematic view of a closed loop control system for the light path of a reflective heliostat of the invention;
FIG. 2 is a schematic view of a closed loop control system for the optical path of the direct projection heliostat of the invention;
FIG. 3 is a schematic view of solar spot or solar image decentration;
FIG. 4 is a schematic view of a heliostat rotation mode according to an embodiment of the invention;
FIG. 5 is a numerical decomposition of rotational misalignment based on a first heliostat rotation;
FIG. 6 is a schematic view of a second heliostat rotation mode of an embodiment of the invention;
FIG. 7 is a numerical decomposition of rotational misalignment based on a second heliostat rotation pattern;
FIG. 8 is a schematic diagram of a reflective spot sensor based on an image capture array;
FIG. 9 is a schematic diagram of the actual position of a solar facula of the reflective facula sensor based on an image collection array;
FIG. 10 is a schematic diagram of a reflective spot sensor based on a photoelectric sensor;
FIG. 11 is a schematic diagram of a reflective spot sensor based on a photosensor and a standard mirror;
FIG. 12 is a schematic diagram of the actual position of the solar spot based on the photoelectric sensor;
FIG. 13 is a schematic diagram of a receiver plate based reflective spot sensor;
FIG. 14 is a schematic diagram of the actual position of a solar spot based on a receiver plate;
FIG. 15 is a schematic diagram of a direct beam spot sensor based on an image capture array;
fig. 16 is a schematic diagram of the actual position of the direct-illumination facula sensor solar image based on the image acquisition array.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
In the figure: the method comprises the following steps of 1-a light spot sensor, 2-a heliostat rotation controller, 3-a calculation unit, 4-a receiving surface, 5-a heliostat reflecting surface, 6-a target area, 7-actual reflected light direction, 8-expected reflected light direction, 9-actual incident light direction, 10-expected incident light direction, 11-an image collector, 12-a photoelectric sensor, 13-a diaphragm, 14-a standard plane reflector, 15-a receiving plate and 16-an image collecting array.
The invention discloses a heliostat light path closed-loop control system, which comprises: the device comprises a facula sensor 1, a
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