CN111765657B - Heliostat light path closed-loop control system and method - Google Patents

Heliostat light path closed-loop control system and method Download PDF

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CN111765657B
CN111765657B CN202010649775.7A CN202010649775A CN111765657B CN 111765657 B CN111765657 B CN 111765657B CN 202010649775 A CN202010649775 A CN 202010649775A CN 111765657 B CN111765657 B CN 111765657B
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heliostat
solar
image
moment
target
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CN111765657A (en
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陈煜达
陈昊
孙楠
沈平
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Shanghai Parasol Renewable Energy Co ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S50/00—Arrangements for controlling solar heat collectors
    • F24S50/20—Arrangements for controlling solar heat collectors for tracking
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D3/00—Control of position or direction
    • G05D3/12—Control of position or direction using feedback
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/40—Solar thermal energy, e.g. solar towers
    • Y02E10/47—Mountings or tracking

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  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Thermal Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
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  • Automation & Control Theory (AREA)
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Abstract

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 calculation unit is used for 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; the heliostat rotation controller is fixed on a target heliostat; and data exchange is carried out between the calculation unit and the heliostat rotation controller and between the heliostat rotation controller and the facula sensor. The invention 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 closed loop control system of the light path of the heliostat.

Description

Heliostat light path closed-loop control system and method
Technical Field
The invention belongs to the technical field of solar photo-thermal power generation, and particularly relates to a heliostat light path closed-loop control system and method in tower type solar energy.
Background
As a core component of a tower solar photo-thermal power plant, heliostats function to reflect sunlight striking its surface to a target absorber region. Because the sun constantly changes position along with time, so heliostat need possess sufficient control accuracy in order to guarantee that the directional precision of reflected light satisfies the design requirement, promptly that the solar energy that reflects through heliostat can constantly, accurately shine to target absorber region to guarantee the collection efficiency of absorber region solar energy and solar photo-thermal power station's work efficiency.
The existing heliostat control mode is based on open loop control, and the core of the existing heliostat control mode is a heliostat motion model. Firstly correcting and obtaining a heliostat motion model in an iterative mode through methods such as a calibration white board and an image collector, and then predicting operation information required by the heliostat according to a calculation result of a sun position and the heliostat motion model, namely generating an operation table comprising time and rotation angle, and finally controlling the heliostat to rotate according to the operation table by a heliostat transmission control mechanism.
The heliostat open-loop control method has the following problems: 1) Requiring a long debug time. The open loop control method relies on heliostat motion models, and control accuracy is ensured by correcting the motion models. The conventional motion model correction method is a calibration white board method, namely, the sun light spots of the target heliostat are reflected to a target calibration white board area in different time periods, then the image is analyzed through an image acquisition system to determine the actual position of the center of the reflected light spots, and finally the motion model of the target heliostat is solved based on time information and the center position of the reflected light spots. Another heliostat motion model correction method is to install an image acquisition system rotating along with the rotation of the heliostat on the heliostat, wherein the image acquisition system takes the sun or other celestial bodies with certain brightness as a target, and solves the motion model of the target heliostat based on the deviation between the position of the center of the target on the image plane and the center of the image plane. No matter what heliostat motion model is adopted for correction, a long debugging time is required to continuously carry out iterative correction on the motion model. Only when the precision of the corrected motion model meets the design requirement, the deviation between the estimated heliostat operation information and the actual operation condition can meet the design requirement, and the precision of heliostat open-loop control can be effectively ensured. 2) Real-time feedback is not available. The existing open loop control method relies on a motion model to estimate operation information of the heliostat and performs 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, and cannot feed back the accuracy of the actual attitude of the heliostat, so that the heliostat has no automatic deviation rectifying capability. Because the motion model is an abstract induction of the actual running situation of the heliostat, the obtained estimated result is only close to the actual situation and cannot fully represent the actual situation, and therefore the gesture of the heliostat controlled based on the motion model has a certain deviation from the gesture of an actual target. Because of no real-time feedback, heliostats cannot handle some abnormal conditions, such as non-idealities that cannot be corrected by a model, surface shape changes caused by wind, and the like, in a partial area of a travel range. 3) The performance index of the mechanical transmission mechanism is higher. In order to ensure the accuracy and stability of open loop control, the heliostat mechanical transmission mechanism needs to have higher performance index requirements, including repeatability accuracy requirements, rotation consistency requirements and the like. If the performance index is poor, namely, the 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 under the open-loop control state is uncontrollable. This also affects the efficiency of the solar energy collection in the absorber area and even creates a safety hazard due to uncontrollable reflected light pointing.
Therefore, a high-precision and high-efficiency heliostat light path closed-loop control system is needed to accurately correct the real-time attitude of the heliostat, so that the reflected solar light spots can be accurately irradiated to a target area, and the concentration efficiency of solar light energy in a heater area and the photo-thermal conversion efficiency of a solar photo-thermal power station are ensured.
Disclosure of Invention
In order to solve the problems, the invention aims at the characteristic of high heliostat control precision requirement in the tower type solar photo-thermal power generation technology, utilizes the light path reflection principle to realize the real-time control of the heliostat posture by controlling the incident light direction or the reflected light direction, effectively solves the problem that the heliostat posture cannot be corrected in real time based on the 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 relates to a heliostat light path closed-loop control system, which comprises: the 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 calculation unit is used for calculating the actual position of the solar facula or the solar image of the target heliostat, calculating the expected position of the solar facula or the solar image of the target heliostat, calculating the deviation between the actual position of the solar facula and the expected position or the deviation between the actual position of the solar image and the expected position, and converting the deviation between the solar facula or the solar image position into a heliostat rotation correction value. The heliostat rotation controller is fixed on the target heliostat and has the function of controlling the rotation of the heliostat. The data exchange is carried out between the calculation unit and the heliostat rotation controller in a wired or wireless mode, and the data exchange is carried out between the heliostat rotation controller and the facula sensor in a wired or wireless mode.
The heliostat light path closed-loop control system is divided into a reflective type and a direct type according to different working modes of the light spot sensor. The principle of reflection is that the reflected light pointing information of a target heliostat at the moment is obtained by sensing the actual position of a solar facula; the direct incidence principle is that the incident light direction information of a target heliostat at the moment is obtained by sensing the actual position of a solar image.
The receiving surface of the facula sensor in the reflective heliostat light path closed-loop control system faces the target heliostat reflecting surface and is used for receiving solar facula reflected by the heliostat reflecting surface, and the value range of the angle delta between the normal line of the receiving surface and the normal line of the target heliostat reflecting surface is more than 90 degrees and less than or equal to 180 degrees. The sunlight irradiates the target area after being reflected, and one 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 energy distribution centroid of the solar spot, which characterizes the actual reflected light pointing of the target heliostat. The reflective optical path closed-loop control system senses the actual reflected light direction of the target heliostat through the spot sensor, corrects the attitude of the heliostat in real time according to the deviation between the actual reflected light direction and the expected reflected light direction, and achieves real-time optical path closed-loop control of the heliostat.
The receiving surface of the facula sensor in the direct-injection heliostat light path closed-loop control system and the reflecting surface of the target heliostat face in the same direction (simultaneously face the sun), and the value range of the angle delta between the normal line of the receiving surface and the normal line of the reflecting surface of the target heliostat is more than or equal to 0 degree and less than 90 degrees. Part of sunlight is received by the receiving surface of the facula sensor to form a solar image, and the rest of sunlight is reflected to a target area through the heliostat reflecting surface; the actual position of the sun image may be described by the geometric center or energy distribution centroid of the sun image, which characterizes the actual incident light direction of the target heliostat. The direct light path closed-loop control system senses the actual incident light direction of the target heliostat through the light spot sensor, corrects the attitude of the heliostat in real time according to the deviation between the actual incident light direction and the expected incident light direction, and achieves real-time light path closed-loop control of the heliostat.
The working flow of the heliostat light path closed-loop control system is as follows:
(1) the spot sensor at time ti collects the distribution information of the solar spots or the solar images, and the computing unit computes the actual position [ u ] of the solar spots or the solar images based on the distribution information of the solar spots or the solar images ti ,v ti ] n Where ti represents the ith point in time during a single workday, n represents the heliostat number, u ti U-axis direction value, v representing actual position of sun light spot or sun image at time ti ti A v-axis direction value representing the actual position of a solar facula or solar image at the moment ti;
(2) The calculation unit calculates expected position information [ Tu ] of a solar facula or solar image of a target heliostat at the moment ti ti ,Tv ti ]，Tu ti U-axis direction value, tv representing expected position of sun spot or sun image at time ti ti A v-axis direction value representing a desired position of a solar facula or solar image at the moment ti;
(3) The calculation unit calculates the sun light spot or sun image position deviation [ delta u ] of the target heliostat ti ,Δv ti ] n ＝[Tu ti -u ti ,Tv ti -v ti ] n ，Δu ti Representing the relative deviation between the expected coordinate and the actual coordinate of the sun light spot or the sun image in the u-axis direction at the moment ti, and Deltav ti Representing the relative deviation between the expected coordinates and the actual coordinates of the sun light spot or the sun image in the v-axis direction at the moment ti;
(4) The heliostat rotates around at least two axes to reflect sunlight to a target area, and the calculation unit calculates the position deviation [ delta u ] of the sun spot or the sun image of the target heliostat at the moment ti according to the rotation mode of the heliostat ti ,Δv ti ] n And converting into a rotation deviation value of the heliostat.
According to the rotation mode I of the heliostat, the heliostat reflecting surface rotates around the X axis and the Y axis of two mutually orthogonal rotating shafts, wherein the Y axis position is kept unchanged, and the X axis rotates around the Y axis along with the heliostat reflecting surface. Rotational deviation value:
Wherein: u (u) 1/2 Representing the u-axis direction coordinate of the center of the receiving surface, v 1/2 Representing the v-axis directional coordinate of the center of the receiving surface, d representing the distance from the receiving surface to the reflecting surface of the heliostat,indicating X-axis rotational deviation +.>Indicating Y-axis rotational bias.
In the second rotation mode of the heliostat, the mirror surface of the heliostat rotates around the Y axis and the Z axis of two mutually orthogonal rotating shafts,
wherein the Z-axis position remains unchanged and the Y-axis rotates around the Z-axis with the heliostat reflective surface. Rotational deviation value:
wherein:indicating the Z-axis rotational deviation.
(5) The heliostat rotation controller corrects the attitude of the target heliostat at the ti moment in real time according to the rotation deviation value, so that the actual position [ u ] of the solar facula or the solar image ti ,v ti ] n Continuously approaching or coinciding with the desired position [ Tu ] ti ,Tv ti ]The method comprises the steps of carrying out a first treatment on the surface of the (6) Repeating the steps (1) - (5) in a single working day, and continuously correcting the posture of the target heliostat in real time by using the deviation between the actual position of the solar light spot or the solar image and the expected position as feedback by the calculation unit so as to enable the actual position of the solar light spot or the solar image at any momentAnd the heliostat fluctuates near the expected position, so that the closed loop control of the heliostat light path is realized, and the reflected light direction of the heliostat can be ensured to be correctly irradiated to the target area.
The calculation unit of the heliostat closed-loop control system calculates the expected position of the target heliostat solar facula or solar image as follows:
(1) The calculating unit calculates the central coordinate of the target heliostat according to the ti momentAnd a target pointing point [ tx ] n ,ty n ,tz n ]Calculating the normalized reflection vector at the moment:
where || denotes a modulo operation,representing the X-axis direction value of the central coordinate of the target heliostat at the moment ti,/>Representing the Y-axis direction value of the central coordinate of the target heliostat at the moment ti,/>Representing Z-axis direction value, tx of central coordinate of target heliostat at time ti n Representing the X-axis direction value and ty of the coordinate of the target pointing point at the moment ti n Indicating Y-axis direction value, tz of coordinates of target pointing point at time ti n Indicating the Z-axis direction value of the coordinate of the target pointing point at the moment ti,/->Representing the X-axis direction component of the normalized reflection vector at time ti,/->Representing the Y-axis directional component of the normalized reflection vector at time ti，/>Representing a Z-axis direction component of a ti moment normalized reflection vector;
(2) The calculating unit calculates the normalized sunlight incidence vector at the moment ti Representing the component of the X-axis direction of the normalized sunlight incidence vector at time ti,/->Represents the Y-axis direction component of the normalized sunlight incidence vector at the moment ti,>representing a Z-axis direction component of a normalized sunlight incidence vector at the moment ti;
(3) The calculating unit calculates a normalized normal vector of the heliostat reflecting surface at the moment:
wherein:representing the normalized normal vector X-axis direction component of the reflecting surface of the heliostat at the moment ti,/and >Representing the normalized normal vector Y-axis direction component of the reflecting surface of the heliostat at the moment ti,/and>representing a normalized normal vector Z-axis direction component of a reflecting surface of the heliostat at the moment ti;
(4) The included angle between the normal vector of the receiving surface of the light spot sensor and the normal vector of the reflecting surface of the heliostat
δ＝[δ n δ u δ v ]Delta in n Representing the deviation angle, delta, of the normal vector around the reflecting surface of the heliostat u Representing the angle of deviation, delta, about the u-axis v Representing the deviation angle about the v-axis; the delta value range in the reflective heliostat closed-loop control system is more than or equal to 90 degrees and less than 180 degrees, and the delta value range in the direct heliostat closed-loop control system is more than or equal to 0 degrees and less than 90 degrees;
the calculating unit calculates the normal vector of the receiving surface based on the included angle delta between the normal vector of the receiving surface of the spot sensor and the normal vector of the reflecting surface of the heliostat:
wherein: n represents the heliostat number, rot u () Representing a rotation matrix about the u-axis, rot v () Representing a rotation matrix about the v-axis, rot n () Representing a rotation matrix around which the heliostat reflection surface normal vector is wound,representing the normalized normal vector X-axis direction component of the receiving surface of the spot sensor at the moment ti,/>Representing the normalized normal vector Y-axis direction component of the receiving surface of the spot sensor at the moment ti, +.>Representing a normalized normal vector Z-axis direction component of a receiving surface of the spot sensor at the moment ti;
(5) In the reflective heliostat closed-loop control system, a calculating unit receives the center coordinates of a surface according to the ti momentAnd a receiving surface normal vector +.>Establishing a three-dimensional equation of the receiving surface, and then carrying out sunlight reflection vector according to ti>And heliostat center coordinates->Establishing a three-dimensional linear equation set based on heliostat mirror surfaces, and solving intersection point coordinates of reflected light pointing direction and receiving surface>Wherein K represents a kth intersection; finally, the intersection point coordinate is converted into a receiving surface coordinate system to obtain the expected position coordinate [ Tu ] of the solar facula ti ,Tv ti ]。
In the direct-injection heliostat closed-loop control system, a calculation unit receives the center coordinates of a surface according to the ti momentAnd a receiving surface normal vector +.>Establishing a three-dimensional equation of the receiving surface, and then carrying out sunlight incidence vector according to the moment ti>And heliostat center coordinates->Establishing a three-dimensional linear equation set based on a heliostat reflecting surface, and solving intersection point coordinates of incident light direction and a receiving surface>Wherein K represents the Kth intersection point, and finally converting the intersection point coordinate to a receiving surface coordinate system to obtain the expected position coordinate of the solar image +.>
In the invention, a facula sensor in the reflective optical path closed-loop control system is composed of an image acquisition array formed by at least one image acquisition device, wherein the image acquisition device is composed of an imaging optical path (a lens or a small hole and the like), a light intensity attenuation device and an image sensor. The sunlight is reflected to the image surface of the image acquisition array through the heliostat reflecting surface to form a solar light spot. The lenses of the image collectors face the heliostat reflecting surface, the number of the image collectors is determined according to the size of the heliostat reflecting surface, and a field of view formed by the image collection arrays can cover the heliostat reflecting surface area.
The solar light spot actual position identification by taking the image acquisition array as a light spot sensor comprises the following steps:
(1) The image acquisition array acquires an image of the heliostat reflecting surface;
(2) Obtaining the area range of the solar light spot in each image collector at the moment ti through a binarization method;
(3) Calculating the geometrical center of the solar facula at the moment based on the solar facula area in the binarized image, or calculating the energy distribution centroid of the solar facula at the moment based on the solar facula area in the gray level image or the color image, and expressing the image coordinates of the actual position (geometrical center or energy distribution centroid) of the solar facula asWherein 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 solar light spot at the moment ti, and l represents the number of pixels in the v-axis direction of the actual position of the solar light spot at the moment ti.
The light spot sensor in the reflective light path closed-loop control system can be an array formed by photoelectric sensors and diaphragms. The photoelectric sensor comprises a photoresistor, a photodiode, a photoswitch and other non-imaging sensors based on photoelectric effect. The receiving surfaces of the photoelectric sensors face the heliostat reflecting surfaces, the number of the photoelectric sensors is determined according to the reflecting ranges of the heliostat reflecting surfaces, and the receiving surfaces formed by the photoelectric sensor arrays can cover solar light spots reflected by the heliostat reflecting surface areas. The sunlight is reflected to the receiving surface of the photoelectric sensor array through the heliostat reflecting surface, and the intensity distribution of the electric signals of the receiving surface generated by the solar light spots is obtained. The diaphragm is used for limiting the range of sunlight irradiated to the light spot sensor so as to form a solar light spot.
The light spot sensor in the reflective light path closed-loop control system can be an array formed by photoelectric sensors and a standard plane reflector. The photoelectric sensor comprises a photoresistor, a photodiode, a photoswitch and other non-imaging sensors based on photoelectric effect. 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 reflecting mirror is determined by the size of the 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 face the sun at the same time in the same direction and are fixed in relative positions. The receiving surfaces of the photoelectric sensors face to the reflecting surfaces of the standard plane reflecting mirrors, and the number of the photoelectric sensors is determined according to the reflecting ranges of the standard plane reflecting mirrors, so that the receiving surfaces formed by the photoelectric sensor arrays can cover solar light spots reflected by the standard plane reflecting mirrors. Sunlight is reflected to the receiving surface of the photoelectric sensor array through the reflecting surface of the standard plane reflecting mirror, and the intensity distribution of the electric signals of the receiving surface generated by the solar light spots is obtained.
The identification of the actual position of the solar facula by taking the photoelectric sensor array as the facula sensor comprises the following steps:
(1) The photoelectric sensor array obtains the intensity distribution of the electric signals of the receiving surface;
(2) According to the intensity distribution of the electric signals, obtaining the range of the photoelectric sensor irradiated by the solar facula on the receiving surface of the photoelectric sensor array at the moment ti based on a preset threshold, namely the range of the photoelectric sensor which is lighted;
(3) Calculating a geometric center based on the illuminated photosensor range or calculating an energy distribution centroid based on the intensity distribution of the electrical signal within the illuminated photosensor range, the actual position (geometric center or energy distribution centroid) coordinates of the solar spot are expressed as [ Ou ] ti ,Ov ti ] n Where n represents the heliostat number, ou represents the value of the u-axis direction of the photosensor array at the actual position of the solar spot at time ti, and Ov represents the value of the v-axis direction of the photosensor array at the actual position of the solar spot at time ti.
The light spot sensor in the reflective light path closed-loop control system can be composed of an image acquisition array formed by a receiving plate and at least one image acquisition device and a standard plane mirror. 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 reflecting surface of the standard plane reflecting mirror and is used for receiving sunlight reflected by the reflecting surface of the standard plane reflecting mirror. The size of the receiving plate covers the reflection range of the standard plane mirror. The standard plane reflector is arranged on the target heliostat and synchronously rotates along with the rotation of the heliostat surface. The size of the standard plane mirror is determined by the resolution of the image acquisition array, and the standard plane mirror reflecting surface and the heliostat reflecting surface are in the same direction (simultaneously facing the sun) and have fixed relative positions. The lenses in the image acquisition array face 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 light spots on the receiving plate, so that a field of view formed by the image acquisition array can cover the area of the receiving plate. The identification of the actual position of the solar facula by taking the receiving plate, the image acquisition array and the standard plane reflector as the facula sensor comprises the following steps:
(1) The receiving plate receives solar light spots reflected by the reflecting surface of the standard plane reflecting mirror;
(2) Collecting an image of a receiving plate through an image collector array, and identifying a sun light spot area at the moment ti through a binarization method;
(3) Calculating the geometrical center of the solar facula at the moment based on the solar facula area in the binarized image By taking the center of the receiving plate as the origin, or calculating the energy distribution centroid of the solar facula at the moment based on the solar facula area in the gray level image or the color image, then the actual coordinate [ By ] of the actual position of the solar facula (geometrical center or energy distribution centroid) on the receiving plate ti ,Bx ti ] n Wherein By represents the time tiAnd the receiving plate u-axis direction value of the actual position of the solar light spot, and Bx represents the v-axis direction value of the receiving plate of the actual position of the solar light spot at the moment ti.
In the invention, the facula sensor in the direct 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, a small hole or the like), 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 reflecting surface of the heliostat (simultaneously faces the sun), and directly collects the sun image, so as to identify the relative position of the actual position of the sun image in the field of view of the image collection array.
The identification of the actual position 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 a region of a solar image in each image collector at the moment ti through a binarization method;
(3) Calculating the geometrical center of the solar image at the moment based on the solar image area in the binarized image or calculating the energy distribution centroid of the solar image at the moment based on the solar image area in the gray image or the color image, the image coordinates of the actual position (geometrical center or energy distribution centroid) of the solar image are expressed asWhere m represents the number of the image collector, h represents the number of u-axis direction pixels of the actual position of the sun image at the moment ti, l represents the number of v-axis direction pixels of the actual position of the sun image at the moment ti, and n represents the number of heliostats.
The invention has the beneficial effects that:
(1) The invention is an optical path closed-loop control system, which dynamically corrects the attitude of the heliostat according to the deviation between the actual position and the expected position of the solar facula or the solar image at any moment, and does not need a heliostat movement model or an operation table calculated based on the movement model.
(2) According to the invention, the light path closed-loop control of the heliostat is realized by controlling the incident light direction or the reflected light direction by utilizing the light path reflection principle, and the heliostat motion model is not required to be corrected in a long debugging time because the heliostat motion model is not depended on, so that the conventional heat collection power generation work can be performed after the heliostat is installed, and the opening efficiency of the tower type solar photo-thermal power station can be effectively improved.
(3) The invention can realize the closed loop control of the light path of the heliostat, identify the actual position of a solar light spot or a solar image based on the light spot sensor, calculate the central position deviation from the expected position, realize the dynamic correction of the attitude of the heliostat by taking the central position deviation as feedback, and effectively ensure the heat collection and power generation efficiency of the heliostat.
(4) According to the heliostat open-loop control method, the operation table is not calculated based on the heliostat motion model to drive the heliostat to rotate, and the heliostat open-loop control precision 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, the requirement on performance indexes such as repeatability precision requirement, rotation consistency requirement and the like of the transmission mechanism is not required to be put forward, and therefore the manufacturing cost of the mechanical transmission mechanism of the heliostat is effectively reduced.
(5) By implementing the optical path closed-loop control on the heliostat, the invention can correct the deformation of the heliostat mirror surface caused by wind vibration, gravity and the like, and effectively improves the adaptability of the heliostat to the environment.
Drawings
FIG. 1 is a schematic diagram of a closed loop control system for the optical path of a reflective heliostat of the invention;
FIG. 2 is a schematic diagram of a closed loop control system for the optical path of a direct-injection heliostat of the invention;
FIG. 3 is a schematic illustration of the off-center deviation of a solar spot or image;
FIG. 4 is a schematic diagram of a heliostat turning manner according to an embodiment of the invention;
FIG. 5 is a rotational bias numerical exploded view based on heliostat rotation one;
FIG. 6 is a diagram illustrating a heliostat rotation in accordance with one embodiment of the invention;
FIG. 7 is a diagram illustrating an exploded view of rotational bias values based on a second heliostat rotation mode;
FIG. 8 is a schematic diagram of a reflective spot sensor based on an image acquisition array;
FIG. 9 is a schematic diagram of the actual position of a solar spot of a reflective spot sensor based on an image acquisition array;
FIG. 10 is a schematic diagram of a photosensor-based reflective spot sensor;
FIG. 11 is a schematic diagram of a reflective spot sensor based on a photosensor and standard mirror;
FIG. 12 is a schematic view of the actual position of a solar spot based on a photosensor;
FIG. 13 is a schematic diagram of a receiving plate based reflective spot sensor;
FIG. 14 is a schematic view of the actual position of a solar spot based on a receiver plate;
FIG. 15 is a schematic diagram of a direct-lit spot sensor based on an image acquisition array;
fig. 16 is a schematic diagram of the actual position of a direct-projection spot sensor solar image based on an image acquisition array.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
In the figure: the system comprises a 1-facula sensor, a 2-heliostat rotation controller, a 3-calculation unit, a 4-receiving surface, a 5-heliostat reflecting surface, a 6-target area, a 7-actual reflected light direction, an 8-expected reflected light direction, a 9-actual incident light direction, a 10-expected incident light direction, an 11-image collector, a 12-photoelectric sensor, a 13-diaphragm, a 14-standard plane reflecting mirror, a 15-receiving plate and a 16-image collection array.
The invention discloses a heliostat light path closed-loop control system, which comprises: the system comprises a light spot sensor 1, a heliostat rotation controller 2 and a calculation unit 3. The spot sensor 1 is fixed on the heliostat reflecting surface 5 and synchronously rotates along with the rotation of the target heliostat reflecting surface 5. The heliostat light path closed-loop control system is divided into a reflective type and a direct type according to different working modes of the facula sensor 1, wherein the reflective type principle is that reflected light pointing information of a target heliostat at the moment is obtained by sensing the actual position of a solar facula, and the direct type principle is that incident light pointing information of the target heliostat at the moment is obtained by sensing the actual position of a solar image. The calculating unit 3 is used for calculating an actual position of a target heliostat solar facula or solar image, calculating an expected position of the target heliostat solar facula or solar image, calculating a deviation of the actual position of the solar facula from the expected position or a deviation of the actual position of the solar image from the expected position, and converting the deviation of the solar facula or solar image position into a heliostat rotation correction value. The heliostat rotation controller 2 is fixed to a target heliostat and functions to control rotation of the heliostat. The calculation unit 3 performs data exchange with the heliostat rotation controller 2 in a wired or wireless mode, and the heliostat rotation controller 2 performs data exchange with the spot sensor 1 in a wired or wireless mode.
Example 1
As shown in fig. 1, the optical path closed-loop control system for a reflective heliostat according to the invention is characterized in that a receiving surface 4 of a spot sensor 1 faces a reflecting surface of a target heliostat reflecting surface 5 and is used for receiving solar spots reflected by the heliostat reflecting surface 5. The sunlight irradiates the target area 6 after being reflected, wherein a part of the sunlight is received by the receiving surface 4 of the light spot sensor 1 to form a solar light spot, and the actual position of the solar light 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, corrects the attitude of the heliostat in real time according to the deviation between the actual reflected light direction 7 and the expected reflected light direction 8, and achieves real-time optical path closed-loop control of the heliostat.
Example 2
As shown in fig. 2, the direct-injection heliostat optical path closed-loop control system of the invention is characterized in that the receiving surface 4 of the spot sensor 1 and the reflecting surface of the reflecting surface 5 of the target heliostat are in the same direction (simultaneously facing the sun). A part of the sunlight is received by the receiving surface 4 of the spot sensor 1 to form a solar image, the rest of the sunlight is reflected to the target area 6 through the heliostat reflecting surface 5, and the actual position of the solar image represents the actual incident light direction 9 of the target heliostat. The direct light path closed-loop control system senses the actual incident light direction 9 of the target heliostat through the spot sensor 1, corrects the attitude of the heliostat in real time according to the deviation between the actual incident light direction 9 and the expected incident light direction 10, and achieves real-time light path closed-loop control of the heliostat.
Example 3
The control method of the heliostat light path closed-loop control system comprises the following steps:
(1) As shown in fig. 3, the spot sensor 1 at time ti collects distribution information of the solar spot or the solar image, and the calculating unit 3 calculates an actual position [ u ] of the solar spot or the solar image based on the distribution information of the solar spot or the solar image ti ,v ti ] n Where ti represents the ith point in time during a single workday, n represents the heliostat number, u ti The u-axis direction actual coordinate of the actual position of the solar facula or solar image at the moment ti is represented by v ti The actual v-axis direction coordinates of the actual position of the solar facula or solar image at the moment ti are represented;
(2) The calculation unit 3 calculates the expected position information [ Tu ] of the sun spot or the sun image of the target heliostat at the time ti ti ,Tv ti ]，Tu ti The expected u-axis direction coordinate of the sun light spot or the sun image at the moment ti is represented by Tv ti The expected v-axis direction coordinates of the solar light spots or the solar images at the moment ti are represented;
(3) The calculation unit 3 calculates the position deviation of the sun spot or the sun image of the target heliostat
[Δu ti ,Δv ti ] n ＝[Tu ti -u ti ,Tv ti -v ti ] n ，Δu ti Representing the relative deviation between the expected coordinate and the actual coordinate of the sun light spot or the sun image in the u-axis direction at the moment ti, and Deltav ti Representing the relative deviation between the expected coordinates and the actual coordinates of the sun light spot or the sun 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 the target area 6, and the calculating unit 3 calculates the position deviation [ delta u ] of the sun spot or the sun image of the target heliostat at the moment ti according to the rotation mode of the heliostat ti ,Δv ti ] n And converting into a rotation deviation value of the heliostat.
As shown in fig. 4, in a first rotation mode of the heliostat, the heliostat reflecting surface 5 rotates around two mutually orthogonal rotation axes X and Y, 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 5. As shown in fig. 5, the rotational deviation value:
wherein: u (u) 1/2 Representing the u-axis direction coordinate of the center of the receiving surface, v 1/2 Representing the receive plane center, v-axis direction coordinates, d representing the receive plane to heliostat reflecting plane 5 distance,indicating the X-axis angular deviation +.>Indicating the Y-axis angular deviation.
As shown in fig. 6, in a second rotation mode of the heliostat, the heliostat reflecting surface 5 rotates around two mutually orthogonal axes of rotation, 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 5. As shown in fig. 7, the rotational deviation value:
wherein:indicating the Z-axis angular deviation.
(5) The heliostat rotation controller 2 corrects the attitude of the target heliostat at the time ti in real time according to the rotation deviation value so that the actual position [ u ] of the solar light spot or the solar image ti ,v ti ] n Continuously approaching or coinciding with the desired position [ Tu ] ti ,Tv ti ]；
(6) And (3) repeating the steps (1) - (5) in a single working day, and continuously correcting the posture of the target heliostat in real time by taking the deviation between the actual position of the solar light spot or the solar image and the expected position as feedback by the calculation unit 3, so that the actual position of the solar light spot or the solar image at any moment fluctuates near the expected position, the closed loop control of the heliostat light path is realized, and the reflected light of the heliostat can be ensured to be correctly irradiated to the target area 6.
The calculation unit 3 of the heliostat closed-loop control system of the invention calculates the expected position of the target heliostat solar facula or solar image as follows:
(1) Calculation unit the calculation unit 3 calculates the central coordinates of the target heliostat according to the ti momentAnd a target pointing point [ tx ] n ,ty n ,tz n ]Calculating the normalized reflection vector at the moment:
where || denotes a modulo operation,representing the X-axis direction value of the central coordinate of the target heliostat at the moment ti,/>Representing the Y-axis direction value of the central coordinate of the target heliostat at the moment ti,/>Representing Z-axis direction value, tx of central coordinate of target heliostat at time ti n Representing the X-axis direction value and ty of the coordinate of the target pointing point at the moment ti n Indicating Y-axis direction value, tz of coordinates of target pointing point at time ti n Indicating the Z-axis direction value of the coordinate of the target pointing point at the moment ti,/- >Representing the X-axis direction component of the normalized reflection vector at time ti,/->Represents the Y-axis directional component of the normalized reflection vector at time ti,/->Representing a Z-axis direction component of a ti moment normalized reflection vector;
(2) The calculation unit 3 calculates the normalized sunlight incidence vector at time ti Representing the component of the X-axis direction of the normalized sunlight incidence vector at time ti,/->Represents the Y-axis direction component of the normalized sunlight incidence vector at the moment ti,>representing a Z-axis direction component of a normalized sunlight incidence vector at the moment ti;
(3) The calculation unit 3 calculates the normalized normal vector of the heliostat reflecting surface 5 at this time:
wherein:representing the normalized normal vector X-axis direction component of the heliostat reflecting surface 5 at time ti,/>Representing the normalized normal vector Y-axis direction component of the heliostat reflecting surface 5 at time ti, +.>Representing the normalized normal vector Z-axis direction component of the heliostat reflecting surface 5 at the moment ti;
(4) Included angle delta= [ delta ] between normal vector of receiving surface 4 of light spot sensor and normal vector of reflecting surface 5 of heliostat n δ u δ v ]Delta in n Representing the deviation angle, delta, of the normal vector around the heliostat reflecting surface 5 u Representing the angle of deviation, delta, about the u-axis v Representing the deviation angle about the v-axis; the delta value range in the reflective heliostat closed-loop control system is more than or equal to 90 degrees and less than 180 degrees, and the delta value range in the direct heliostat closed-loop control system is more than or equal to 0 degrees and less than 90 degrees; the calculating unit 3 calculates the normal vector of the receiving surface 4 based on the angle delta between the normal vector of the receiving surface 4 of the spot sensor 1 and the normal vector of the reflecting surface 5 of the heliostat:
Wherein: n represents the heliostat number, rot u () Representing a rotation matrix about the u-axis, rot v () Representing a rotation matrix about the v-axis, rot n () Representing a rotation matrix around which the heliostat reflection surface normal vector is wound,representing the normalized normal vector X-axis direction component of the receiving surface of the spot sensor at the moment ti,/>Representing the normalized normal vector Y-axis direction component of the receiving surface of the spot sensor at the moment ti, +.>Representing a normalized normal vector Z-axis direction component of a receiving surface of the spot sensor at the moment ti;
(5) In the reflective heliostat closed-loop control system, a calculation unit 3 calculates the center coordinate of a receiving surface 4 according to the ti momentAnd the normal vector of the receiving surface 4->Establishing a three-dimensional equation of the receiving surface 4, and then carrying out sun light reflection vector according to ti moment +.>And heliostat center coordinates->Establishing a three-dimensional linear equation set based on the heliostat reflecting surface 5, and solving the intersection point coordinate of the reflected light direction and the receiving surface 4>Wherein K represents a kth intersection; finally, the intersection point coordinate is converted into a receiving surface 4 coordinate system to obtain the expected coordinate [ Tu ] of the solar light spot ti ,Tv ti ]。
Wherein the method comprises the steps ofRespectively representing the x-axis, y-axis and z-axis direction values of the central coordinate of the heliostat receiving surface 4 with the ti moment number of n; />Respectively representing the x-axis, y-axis and z-axis direction components of the normal vector of the receiving surface 4 of the heliostat with the ti moment number of n; / >The x-axis, y-axis and z-axis direction values of the coordinates of the intersection of the heliostat reflected light direction with the receiving surface 4 at time instant n are shown.
In the direct-injection heliostat closed-loop control system, a calculation unit 3 calculates the central coordinate of a receiving surface 4 according to the ti momentAnd the normal vector of the receiving surface 4->Establishing a three-dimensional equation of the receiving surface 4, and then carrying out sun light incidence vector +.>And heliostat center coordinates->Establishing a three-dimensional linear equation set based on the heliostat reflecting surface 5, and solving intersection point coordinates of the incident light direction and the receiving surface 4>Wherein K represents the Kth intersection point, and finally the intersection point coordinate is converted into a receiving surface 4 coordinate system to obtain the expected coordinate [ Tu ] of the solar image ti ,Tv ti ]。
Wherein the method comprises the steps ofThe x-axis, y-axis and z-axis direction values, respectively, represent the coordinates of the intersection of the incident light of heliostat, numbered n, at time ti, with 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 formed by an image acquisition array formed by at least one image acquisition device 11, and the image acquisition device 11 is formed by an imaging optical path (lens or aperture, etc.), a light intensity attenuation device and an image sensor. The sunlight is reflected to the image surface of the image acquisition array through the reflecting surface of the heliostat reflecting surface 5 to form a solar light spot. The lenses of the image collectors 11 face the heliostat reflecting surface 5, and the number of the image collectors 11 is determined according to the size of the heliostat reflecting surface 5, so that a field of view formed by the image collection array can cover the area of the heliostat reflecting surface 5.
The solar light spot actual position identification by taking the image acquisition array as a light spot sensor comprises the following steps:
(1) The image acquisition array acquires an image of the heliostat reflecting surface 5;
(2) As shown in fig. 9, the area range of the solar light spot in each image collector 11 at the time ti is obtained by a binarization method;
(3) Calculating the geometrical center of the solar facula at the moment based on the solar facula area in the binarized image, or calculating the energy distribution centroid of the solar facula at the moment based on the solar facula area in the gray level image or the color image, and expressing the image coordinates of the actual position (geometrical center or energy distribution centroid) of the solar facula asWherein 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 solar light spot at the moment ti, and l represents the number of pixels in the v-axis direction of the actual position of the solar light spot at the moment ti.
Example 5
As shown in fig. 10, the spot sensor 1 in the reflective optical path closed-loop control system may be an array of photosensors 12 and a diaphragm 13. The photosensor 12 includes a photosensor, a photodiode, an optical switch, and the like, which are non-imaging sensors based on the photoelectric effect. The receiving surface of the photoelectric sensor 12 faces to the reflecting surface of the heliostat reflecting surface 5, and the number of the photoelectric sensors 12 is determined according to the reflecting range of the heliostat reflecting surface 5, so that the receiving surface formed by the photoelectric sensor array can cover solar light spots reflected by the area of the heliostat reflecting surface 5. The sunlight is reflected to the receiving surface of the photoelectric sensor array through the reflecting surface of the heliostat reflecting surface 5, and the intensity distribution of the electric signals of the receiving surface generated by the solar light spots is obtained. The diaphragm 13 is used to limit the range of sunlight striking the spot sensor 1 so as to form a solar spot.
Example 6
As shown in fig. 11, the spot sensor 1 in the reflective optical path closed loop control system may be an array of photosensors 12 and a standard plane mirror 14. The photosensor 12 includes a photosensor, a photodiode, an optical switch, and the like, which are non-imaging sensors based on the photoelectric effect. The standard plane mirror 14 is installed on the target heliostat and rotates synchronously along with the rotation of the heliostat reflecting 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, and the reflecting surface of the standard plane mirror 14 and the reflecting surface of the heliostat reflecting surface 5 are in the same direction (simultaneously face the sun). The receiving surfaces of the photosensors 12 face the reflecting surfaces of the standard plane mirrors 14, and the number of the photosensors 12 is determined according to the reflecting ranges of the standard plane mirrors 14, so that the receiving surfaces formed by the photosensor arrays can cover solar spots reflected by the standard plane mirrors 14. Sunlight is reflected to the receiving surface of the photoelectric sensor array through the reflecting surface of the standard plane reflecting mirror 14, and the intensity distribution of the electric signals of the receiving surface generated by the solar light spots is obtained.
The actual position recognition of the solar light spot using the photosensor array as the light spot sensor in embodiments 5 and 6 includes the following steps:
(1) The photoelectric sensor array obtains the intensity distribution of the electric signals of the receiving surface;
(2) As shown in fig. 12, according to the electric signal intensity distribution, the range of the photoelectric sensor 12 irradiated by the solar spot on the receiving surface of the photoelectric sensor array at the time ti, that is, the range of the photoelectric sensor 12 which is lighted is obtained based on a preset threshold value;
(3) Calculating the geometric center based on the range of the illuminated photosensor 12, or calculating the energy distribution centroid based on the electric signal intensity distribution within the range of the illuminated photosensor 12, the actual position (geometric center or energy distribution centroid) coordinates of the solar spot are expressed as [ Ou ] ti ,Ov ti ] n Where n represents the heliostat number, ou represents the value of the u-axis direction of the photosensor array at the actual position of the solar spot at time ti, and Ov represents the value of the v-axis direction of the photosensor array at the actual position of the solar spot at time ti.
Example 7
As shown in fig. 13, the spot sensor 1 in the reflective optical path closed-loop control system may be formed by an image acquisition array 16 formed by a receiving plate 15 and 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 reflection surface of the standard plane mirror 14 and is used for receiving sunlight reflected by the reflection surface of the standard plane mirror 14. The receiving plate 15 is sized to cover the reflection range of the standard planar mirror 14. The standard plane mirror 14 is mounted on the target heliostat and rotates synchronously with the rotation of the heliostat reflecting surface 5. The size of the standard planar mirror 14 is determined by the resolution of the image acquisition array 16, with the standard planar mirror 14 reflecting surface being co-directional with (facing the sun simultaneously with) the heliostat reflecting surface 5 reflecting surface. The lenses in the image acquisition array 16 face the receiving surface of the receiving plate 15, and the number of the image collectors is determined according to the size of the receiving plate 15 and is used for identifying the actual position of the solar light spots on the receiving plate 15, so that the field of view formed by the image acquisition array 16 can cover the area of the receiving plate 15.
The above-mentioned identification of the actual position of the solar light spot using the receiving plate 15, the image acquisition array 16 and the standard plane mirror 14 as the light spot sensor includes the following steps:
(1) The receiving plate 15 receives solar light spots reflected by the reflecting surface of the standard plane reflecting mirror 14;
(2) Collecting an image of a receiving plate through an image collector array 16, and identifying a sun light spot area at the moment ti through a binarization method;
(3) As shown in fig. 14, with the center of the receiving plate 15 as the origin, the geometrical center of the solar spot at this moment is calculated based on the solar spot area in the binarized image, or the centroid of the solar spot energy distribution at this moment is calculated based on the solar spot area in the gray image or the color image, then the actual coordinates [ By ] of the actual position of the solar spot (geometrical center or centroid of energy distribution) on the receiving plate 15 ti ,Bx ti ] n Wherein By represents the u-axis direction value of the receiving plate of the actual position of the solar light spot at the moment ti, and Bx represents the v-axis direction value of the receiving plate of the actual position of the solar light spot at the moment ti.
Example 8
As shown in fig. 15, the spot sensor 1 in the direct light path closed loop control system is composed of an image acquisition array composed of at least one image acquisition unit 11. The image collector 11 is composed of an imaging optical path (lens or aperture, etc.), a light intensity attenuating 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 is directed in the same direction as the reflecting surface of the heliostat reflecting surface 5 (simultaneously faces the sun), and directly collects the sun image, so as 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 solar image actual position identification using the image acquisition array as the spot sensor 1 includes the following steps:
(1) The image acquisition array acquires an image of the sun;
(2) As shown in fig. 16, the area of the solar image in each image collector 11 at the time ti is obtained by a binarization method;
(3) Calculating the geometrical center of the solar image at the moment based on the solar image area in the binarized image or calculating the energy distribution centroid of the solar image at the moment based on the solar image area in the gray image or the color image, the image coordinates of the actual position (geometrical center or energy distribution centroid) of the solar image are expressed asWhere m represents the number of the image collector, h represents the number of u-axis direction pixels of the actual position of the sun image at the moment ti, l represents the number of v-axis direction pixels of the actual position of the sun image at the moment ti, and n represents the number of heliostats.
Aiming at the characteristic of high control precision requirement of heliostats in the tower type solar photo-thermal power generation technology, the invention utilizes the light path reflection principle to realize the real-time control of the attitudes of the heliostats by controlling the direction of incident light or the direction of reflected light, effectively solves the problem that the attitudes of the heliostats 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 closed-loop control system of the light paths of the heliostats.

Claims (10)

1. A heliostat light path closed loop control system, comprising: the 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 calculation unit is used for calculating the actual position of a target heliostat solar facula or solar image, calculating the expected position of the target heliostat solar facula or solar image, calculating the deviation between the actual position of the solar facula and the expected position or the deviation between the actual position of the solar image and the expected position, and converting the deviation between the solar facula or the solar image position into a heliostat rotation correction value;
the heliostat rotation controller is fixed on the target heliostat and has the function of controlling the rotation of the heliostat;
the data exchange is carried out between the calculation unit and the heliostat rotation controller in a wired or wireless mode, and the data exchange is carried out between the heliostat rotation controller and the facula sensor in a wired or wireless mode;
the heliostat light path closed-loop control system is divided into a reflective type and a direct type according to different working modes of the light spot sensor.
2. The heliostat light path closed-loop control system of claim 1, wherein: the receiving surface of the facula sensor in the reflective heliostat light path closed-loop control system faces the target heliostat reflecting surface and is used for receiving solar rays reflected by the heliostat reflecting surface, and the value range of the angle delta between the normal line of the receiving surface and the normal line of the target heliostat reflecting surface is more than 90 degrees and less than or equal to 180 degrees; the solar rays are reflected and irradiated to a target area, and one part of the solar rays are received by a receiving surface of the light spot sensor to form solar light spots; the actual position of the solar facula can be described by the geometric center or the energy distribution centroid of the solar facula, which characterizes the actual reflected light direction of the target heliostat; the reflective heliostat light path closed-loop control system senses the actual reflected light direction of the target heliostat through the spot sensor, corrects the attitude of the heliostat in real time according to the deviation between the actual reflected light direction and the expected reflected light direction, and achieves real-time light path closed-loop control of the heliostat;
The receiving surface of the facula sensor in the direct-injection heliostat optical path closed-loop control system and the reflecting surface of the target heliostat are in the same direction, and the value range of delta between the normal line of the receiving surface and the normal line of the reflecting surface of the target heliostat is more than or equal to 0 degree and less than 90 degrees; part of sunlight is received by the receiving surface of the facula sensor to form a solar image, and the rest of sunlight is reflected to a target area through the heliostat reflecting surface; the actual position of the solar image can be described by the geometric center or the energy distribution centroid of the solar image, which characterizes the actual incident light direction of the target heliostat; the direct-irradiation heliostat light path closed-loop control system senses the actual incident light direction of the target heliostat through the light spot sensor, corrects the attitude of the heliostat in real time according to the deviation between the actual incident light direction and the expected incident light direction, and achieves real-time light path closed-loop control of the heliostat.
3. The heliostat light path closed-loop control system of claim 1, wherein: the 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 acquisition device; the image collector consists of an imaging light path, a light intensity attenuation device and an image sensor; the sunlight is reflected to the image surface of the image acquisition array through the heliostat reflecting surface to form a solar light spot; the lenses of the image collectors face the heliostat reflecting surface, the number of the image collectors is determined according to the size of the heliostat reflecting surface, and a field of view formed by the image collection arrays can cover the heliostat reflecting surface area.
4. The heliostat light path closed-loop control system of claim 1, wherein: the spot sensor in the reflective heliostat light path closed-loop control system consists of an array formed by photoelectric sensors and diaphragms; the receiving surfaces of the photoelectric sensors face the heliostat reflecting surfaces, the number of the photoelectric sensors is determined according to the reflecting ranges of the heliostat reflecting surfaces, and the receiving surfaces formed by the photoelectric sensor arrays can cover solar rays reflected by the heliostat reflecting surface areas; the solar rays are reflected to a receiving surface of the photoelectric sensor array through a heliostat reflecting surface, and the intensity distribution of electric signals of the receiving surface generated by solar light spots is obtained; the diaphragm is used for limiting the range of sunlight irradiated to the light spot sensor so as to form a solar light spot.
5. The heliostat light path closed-loop control system of claim 1, wherein: the spot sensor in the reflective heliostat light path closed-loop control system consists of an array formed by photoelectric sensors and a standard plane reflector; the standard plane reflecting mirror is arranged on the target heliostat and synchronously rotates along with the rotation of the heliostat reflecting surface, the size of the standard plane reflecting mirror is determined by the size of the 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 fixed in relative positions; the receiving surfaces of the photoelectric sensors face to the reflecting surfaces of the standard plane reflecting mirrors, and the number of the photoelectric sensors is determined according to the reflecting ranges of the standard plane reflecting mirrors, so that the receiving surfaces formed by the photoelectric sensor arrays can cover solar light spots reflected by the standard plane reflecting mirrors; sunlight is reflected to the receiving surface of the photoelectric sensor array through the reflecting surface of the standard plane reflecting mirror, and the intensity distribution of the electric signals of the receiving surface generated by the solar light spots is obtained.
6. The heliostat light path closed-loop control system of claim 1, wherein: the spot sensor in the reflective heliostat light path closed-loop control system is composed of an image acquisition array formed by a receiving plate and at least one image acquisition device and a standard plane mirror; 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 reflecting surface of the standard plane reflecting mirror and is used for receiving sunlight reflected by the reflecting surface of the standard plane reflecting mirror; the size of the receiving plate covers the reflection range of the standard plane reflector; the standard plane reflecting mirror is arranged on the 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 resolution of the image acquisition array, and the reflecting surface of the standard plane reflecting mirror and the reflecting surface of the heliostat are in the same direction and have fixed relative positions; the lenses in the image acquisition array face 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 light spots on the receiving plate, so that a field of view formed by the image acquisition array can cover the area of the receiving plate.
7. The heliostat light path closed-loop control system of claim 1, wherein: the facula sensor in the direct-irradiation heliostat 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 light intensity attenuation device and an image sensor; the view field 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 in the same direction as the reflecting surface of the heliostat, directly collects the sun image, and is used for identifying the relative position of the sun image in the view field of the image collection array.
8. The heliostat light path closed-loop control method is characterized by comprising the following steps:
(1) the spot sensor at time ti collects the distribution information of the solar spots or the solar images, and the computing unit computes the actual position [ u ] of the solar spots or the solar images based on the distribution information of the solar spots or the solar images ti ,v ti ] n Where ti represents the ith point in time during a single workday, n represents the heliostat number, u ti U-axis direction value, v representing actual position of sun light spot or sun image at time ti ti A v-axis direction value representing the actual position of a solar facula or solar image at the moment ti;
(2) The calculation unit calculates expected position information [ Tu ] of a solar facula or solar image of a target heliostat at the moment ti ti ,Tv ti ]，Tu ti U-axis direction value, tv representing expected position of sun spot or sun image at time ti ti A v-axis direction value representing a desired position of a solar facula or solar image at the moment ti;
(3) The calculation unit calculates the sun light spot or sun image position deviation [ delta u ] of the target heliostat ti ,Δv ti ] n ＝[Tu ti -u ti ,Tv ti -v ti ] n ，Δu ti Representing the relative deviation between the expected coordinate and the actual coordinate of the sun light spot or the sun image in the u-axis direction at the moment ti, and Deltav ti Representing the relative deviation between the expected coordinates and the actual coordinates of the sun light spot or the sun 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 calculatesThe unit is used for driving the target heliostat to generate a sun spot or a sun image position deviation [ delta u ] at the moment ti according to the rotation mode of the heliostat ti ,Δv ti ] n Converting into a rotation deviation value of the heliostat;
(5) The heliostat rotation controller corrects the attitude of the target heliostat at the ti moment in real time according to the rotation deviation value, so that the actual position [ u ] of the solar facula or the solar image ti ,v ti ] n Continuously approaching or coinciding with the desired position [ Tu ] ti ,Tv ti ]；
(6) And (3) repeating the steps (1) - (5) in a single working day, and continuously correcting the posture of the target heliostat in real time by taking the deviation between 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 at any moment fluctuates near the expected position, the closed loop control of the heliostat light path is realized, and the reflected light of the heliostat can be ensured to be correctly irradiated to the target area.
9. The method of claim 8, wherein in the step (4), the heliostat rotates in a manner of one: the heliostat reflecting surface rotates around two mutually orthogonal rotating shafts, namely an X axis and a Y axis, 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 value:
wherein: u (u) 1/2 Representing the u-axis direction coordinate of the center of the receiving surface, v 1/2 Representing the v-axis directional coordinate of the center of the receiving surface, d representing the distance from the receiving surface to the reflecting surface of the heliostat,indicating X-axis rotational deviation +.>Indicating Y-axis rotation deviation;
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 value:
wherein:indicating the Z-axis rotational deviation.
10. The method according to claim 8, wherein in the step (1), the step of calculating the desired position of the target heliostat solar spot or solar image by the calculation unit is as follows:
(1) The calculating unit calculates the central coordinate of the target heliostat according to the ti momentAnd a target pointing point [ tx ] n ,ty n ,tz n ]Calculating the normalized reflection vector at the moment:
Where || denotes a modulo operation,representing the X-axis direction value of the central coordinate of the target heliostat at the moment ti,/>Representing the Y-axis direction value of the central coordinate of the target heliostat at the moment ti,/>Representing Z-axis direction value, tx of central coordinate of target heliostat at time ti n Representing the X-axis direction value and ty of the coordinate of the target pointing point at the moment ti n Indicating Y-axis direction value, tz of coordinates of target pointing point at time ti n Indicating the Z-axis direction value of the coordinate of the target pointing point at the moment ti,/->Representing the ti time normalized reflection vector X-axis direction component,represents the Y-axis directional component of the normalized reflection vector at time ti,/->Representing a Z-axis direction component of a ti moment normalized reflection vector;
(2) The calculating unit calculates the normalized sunlight incidence vector at the moment ti Representing the component of the X-axis direction of the normalized sunlight incidence vector at time ti,/->Represents the Y-axis direction component of the normalized sunlight incidence vector at the moment ti,>representing a Z-axis direction component of a normalized sunlight incidence vector at the moment ti;
(3) The calculating unit calculates a normalized normal vector of the heliostat reflecting surface at the moment:
wherein:representing the normalized normal vector X-axis direction component of the reflecting surface of the heliostat at the moment ti,/and>representing the normalized normal vector Y-axis direction component of the reflecting surface of the heliostat at the moment ti,/and >Representing a normalized normal vector Z-axis direction component of a reflecting surface of the heliostat at the moment ti;
(4) Included angle delta= [ delta ] between receiving surface normal vector of light spot sensor and reflecting surface normal vector of heliostat n δ u δ v ]Delta in n Representing the deviation angle, delta, of the normal vector around the reflecting surface of the heliostat u Representing the angle of deviation, delta, about the u-axis v Representing the deviation angle about the v-axis; the delta value range in the reflective heliostat closed-loop control system is more than or equal to 90 degrees and less than 180 degrees, and the delta value range in the direct heliostat closed-loop control system is more than or equal to 0 degrees and less than 90 degrees;
the calculating unit calculates the normal vector of the receiving surface based on the included angle delta between the normal vector of the receiving surface of the spot sensor and the normal vector of the reflecting surface of the heliostat:
wherein: n represents the heliostat number, rot u () Representing a rotation matrix about the u-axis, rot v () Representing a rotation matrix about the v-axis, rot n () Representing a rotation matrix around which the heliostat reflection surface normal vector is wound,representing the normalized normal vector X-axis direction component of the receiving surface of the spot sensor at the moment ti,/>Representing the normalized normal vector Y-axis direction component of the receiving surface of the spot sensor at the moment ti, +.>Representing a normalized normal vector Z-axis direction component of a receiving surface of the spot sensor at the moment ti;
(5) In the reflective heliostat closed-loop control system, a calculating unit receives the center coordinates of a surface according to the ti moment And a receiving surface normal vector +.>Establishing a three-dimensional equation of the receiving surface, and then carrying out sunlight reflection vector according to ti>And heliostat center coordinates->Establishing a three-dimensional linear equation set based on a heliostat reflecting surface, and solving intersection point coordinates of the reflected light direction and a receiving surface>Wherein K represents a kth intersection; finally, the intersection point coordinate is converted into a receiving surface coordinate system to obtain the expected position coordinate [ Tu ] of the solar facula ti ,Tv ti ]；
In the direct-injection heliostat closed-loop control system, a calculation unit receives the center coordinates of a surface according to the ti momentAnd a receiving surface normal vector +.>Establishing a three-dimensional equation of the receiving surface, and then according to the sunlight incidence vector at the moment tiAnd heliostat center coordinates->Establishing a three-dimensional linear equation set based on a heliostat reflecting surface, and solving intersection point coordinates of incident light direction and a receiving surface>Wherein K represents the Kth intersection point, and finally converting the intersection point coordinate to a receiving surface coordinate system to obtain the expected coordinate [ Tu ] of the solar image ti ,Tv ti ]。
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