CN102354226B - Heliostat calibration system of solar power station and calibration method - Google Patents
Heliostat calibration system of solar power station and calibration method Download PDFInfo
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- CN102354226B CN102354226B CN201110303115.4A CN201110303115A CN102354226B CN 102354226 B CN102354226 B CN 102354226B CN 201110303115 A CN201110303115 A CN 201110303115A CN 102354226 B CN102354226 B CN 102354226B
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- 238000000034 method Methods 0.000 title claims abstract description 22
- 238000012545 processing Methods 0.000 claims abstract description 3
- 238000001816 cooling Methods 0.000 claims description 9
- 238000004091 panning Methods 0.000 claims description 4
- 230000000903 blocking effect Effects 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 230000009977 dual effect Effects 0.000 description 3
- 238000010248 power generation Methods 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000005611 electricity Effects 0.000 description 2
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- 230000001678 irradiating effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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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
- F24S2050/25—Calibration means; Methods for initial positioning of solar concentrators or solar receivers
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Abstract
The invention discloses a heliostat calibration system of a solar power station, which comprises a receiver, a heliostat field, an image sensor group and a control unit. The heliostat field is arranged around the receiver; the image sensor group is used for capturing a light spot reflected by a heliostat formed via irradiation of a calibration light source; the control unit is used for processing image information obtained by the image sensor group, calibrating and tracking parameters of the heliostat of the sun and controlling rotation of the heliostat; and the image sensor group is arranged on the heliostat field, so that an image reflected by the heliostat falls into the collection scope of the image sensor group. The center position of the light spot reflected by the heliostat can be obtained by the control unit according to the image information of the image sensor group, and finally an error of the heliostat to be calibrated can be obtained. Since the center position of the light spot reflected by the heliostat is determined via movement of the image sensor group, the calibration can be completed rapidly, the mechanical error is small, and the calibration accuracy can be improved. The invention simultaneously discloses a calibration method of the calibration system.
Description
Technical Field
The invention belongs to the field of solar power generation, and particularly relates to a heliostat calibration system and a tracking method of a solar power station.
Background
In a central tower receiver power plant, the receiver at the top of the tower receives the sunlight reflected from the heliostat group. The receiver converts incident radiant energy to output high-pressure high-temperature steam, and then the steam can be sent to a turbine to generate electricity. The heliostats are typically mounted to the ground around the tower. Each heliostat has a rigid reflective surface that tracks the sun, and the surface adopts a sunny orientation during the day, keeping reflecting moving sunlight to the receiver. A high degree of accuracy in tracking the sun is required to reduce the reflected light that spills around the receiver. Therefore, it is a technical problem to be solved by those skilled in the art to provide a heliostat calibration system capable of accurately tracking the sun and realizing less loss.
In order to solve the above problems, a common calibration method of the conventional heliostat calibration system is as follows: the method comprises the steps of detecting the spatial position of a light spot of sunlight reflected by a heliostat through an image sensor, namely the central position of the light spot, and the rotating angle of the corresponding heliostat, wherein the rotating angle refers to the pitch angle phi and the yaw angle omega of the heliostat, obtaining an error value required to be calibrated by the heliostat, updating parameters of the heliostat in a database according to the obtained error value, calculating an angle required to rotate when the heliostat reflects the sunlight on a receiver according to the parameters and the position of the receiver and the sun, and starting tracking.
For example, chinese patent CN101918769A discloses a heliostat scaling and tracking control method in a central tower receiver solar power plant, comprising a field of heliostats reflecting sunlight to the receiver, a camera directed at least a certain subset of the heliostats. The camera is configured to produce an image of sunlight reflected from a plurality of heliostats. The system is calibrated by the above-mentioned calibration method. In the calibration process, the process of determining the spot center position is as follows: the method comprises the steps that firstly, light spots reflected by a heliostat are captured through a camera, the heliostat is in initial configuration at the moment, in order to enable the camera to find the center position of the reflected light spots of the heliostat, a control system controls the heliostat to rotate, and finally the heliostat is rotated until the camera captures the center position of the light spots. FIG. 1 is a trajectory diagram of heliostat rotations performed when obtaining a spot center sample using a camera, the orientation of the heliostat being controlled at two rotation angles, a pan angle ω and a pitch angleThe pan angle ω is represented along the horizontal axis. Pitch angleShown along the vertical axis. According to the track graph, the system can reach the position where the camera can detect the center of the light spot by rotating the heliostat for multiple times. The control scheme is complex, and the calibration action is slow; meanwhile, mechanical errors are introduced by multiple track rotations of the heliostat, and the calibration precision is reduced. In addition, in larger power plants, the rotation of a large number of heliostats consumes power from the calibration motors that control the rotation of the heliostats. For another example, in US patent US20100139644, although the rotation trajectory of the heliostat is simplified compared with CN101918769A during calibration, in order to obtain the reflection spot profile position of the heliostat, a control system is still needed to control a large number of heliostats to rotate to a position where the camera can capture the reflection spot profile position; thus, the reflected light spot of the heliostat cannot be irradiated on the receiver, and the power generation efficiency is influenced.
Disclosure of Invention
Therefore, the invention aims to solve the technical problem that the conventional heliostat calibration system is complex in calibration action, and provides the heliostat calibration system of the solar power station, which has high calibration precision, high calibration speed and low operation cost.
In order to solve the above technical problem, the present invention provides a heliostat calibration system for a solar power plant, including: a receiver for receiving sunlight reflected by a heliostat; heliostat field of at least one heliostat: mounted around the receiver; an image sensor group of at least one image sensor: the heliostat is used for collecting a calibration light source reflection image of the heliostat; and a control unit: the heliostat control system is used for processing image information obtained by the image sensor group, calibrating parameters of a heliostat for tracking the sun and controlling the rotation of the heliostat; the image sensor is arranged on the heliostat field, so that the reflected image of the heliostat reflected to the outside of the receiver falls into the acquisition range of the image sensor group.
The calibration light source reflection image of the heliostat collected by the image sensor group is a spot and is used for obtaining the outline of a reflection light spot of the heliostat; when the control unit controls the heliostat to rotate and enables the reflecting light spot of the heliostat to be aligned to the receiver, the image sensor group collects the image of the reflecting light spot of the heliostat, and the control unit determines the central position of the reflecting light spot of the heliostat according to the image information collected by the image sensor group and calibrates the heliostat.
The image sensor is movably mounted on a mounting bracket located between the receiver and the heliostat field, the image sensor surrounds the circumference of the receiver and the image sensor acquisition surface is arranged facing the receiver and moves up and down along the mounting bracket.
The image sensors are arranged on the rotary mounting support in a vertically movable mode, the image sensors are arranged along the horizontal direction, the acquisition surface of each image sensor faces the receiver, and the rotary mounting support can rotate around the supporting tower of the receiver.
The image sensor group and the heliostat field are respectively arranged at two opposite sides of the receiver, the image sensors are movably arranged on the plane mounting bracket, and the image sensor group is arranged along the horizontal or vertical direction and moves up and down or left and right along the plane mounting bracket.
The image sensor group is fixedly mounted on a fixed mounting support located between the receiver and the heliostat, and the fixed mounting support is arranged around a receiving surface of the receiver.
The image sensor group is provided with light reducing means for reducing the intensity of light, the light reducing means comprising light reflecting means and/or light absorbing means.
The dimming device is a dimming device capable of adjusting dimming intensity.
The image sensor group is provided with a shading device for shading sunlight.
The image sensor group is configured with a light intensity sensor for measuring light intensity.
The image sensor group is provided with a cooling device which is an air cooling device or a water cooling device.
The heliostat is provided with two rotating shafts, and the heliostat performs pitching rotation and panning rotation around the rotating shafts; the dual axes of rotation are equipped with angle sensors for accurately determining the actual angle through which the two axes of rotation have rotated.
The heliostat is provided with two rotating shafts, and the heliostat respectively rotates around the two rotating shafts in a pitching manner; the dual axes of rotation are equipped with angle sensors for accurately determining the actual angle through which the two axes of rotation have rotated.
The calibration system also includes a sun tracking sensor for tracking the position of the sun in real time.
The calibration system further comprises a position sensor arranged on the moving track of the image sensor group and used for determining the positions of the receiver and the image sensor.
The calibration light source is a sunlight light source or an artificial light source.
The invention also discloses a calibration method of the heliostat calibration system applying the solar power station, which comprises the following steps:
a. the control unit controls the heliostat to rotate so that a reflection light spot of the heliostat is aligned to the receiver;
b. the control unit determines the central position of a light spot reflected by the heliostat and the corresponding heliostat according to the image collected by the image sensor group, and obtains the rotation angle of the heliostat through the measurement value of the angle sensor or the command of the control unit;
c. the control unit controls the heliostat to rotate, so that a reflection light spot of the heliostat reaches a position which can be detected by the image sensor;
d. repeating the steps b-c for at least n/2 times according to the number n of error values to be calibrated;
e. and calculating an error value required to be calibrated according to the obtained light spot center position and the rotation angle information of the heliostat, and storing the calibrated error value to the control unit.
And b, collecting the reflection image of the heliostat by the image sensor group in a mode of moving up and down, or moving left and right, or rotating and moving, so that the reflection image of the heliostat reflected to the outside of the receiver falls into the collection range of the image sensor group.
And c, when the light spots acquired by the image sensor in the step b are partial light spots, the control unit controls the heliostat to rotate so that the whole light spot falls on a position which can be captured by the image sensor group.
Compared with the prior art, the technical scheme of the invention has the following advantages:
(1) compared with the mode that the center of the heliostat is aligned to the image sensor through the continuous rotation of the heliostat and the center position of the light spot is captured by the image sensor finally in the prior art, the calibration method has the advantages of quick calibration action, small mechanical error and high calibration precision.
(2) Furthermore, the image sensor can be movably arranged around the receiver, and the image sensor is not arranged at the position of the receiving surface of the receiver, so that the equipment cost is reduced; when the image sensor moves, the image sensor can only collect the heliostats which do not irradiate on the receiver, and meanwhile, the control unit only calibrates the heliostats which do not irradiate on the receiver. The heliostats on the remaining alignment receivers can continue to operate normally. Compared with the calibration system completely separated from power generation in the prior art, the solar power station has higher efficiency.
(3) The calibration light source can be sunlight or an artificial light source, the calibration can be carried out through the sunlight in a sunny day, and the calibration of the heliostat can be realized through the artificial light source in a cloudy day or at night.
Drawings
In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which
FIG. 1 is a prior art trajectory plot of heliostat rotations performed when a camera is used to obtain a spot center sample;
FIG. 2 is a schematic view of the heliostat alignment system in embodiment 1;
FIG. 3 is a pattern of spots obtained when the image sensor is moved;
FIG. 4 is a top view of the heliostat alignment system of embodiment 1;
FIG. 5 is a schematic diagram of an image sensor structure having a light reduction device;
FIG. 6 is a schematic diagram of an image sensor with a light reduction device and a light blocking device;
FIG. 7 is a block diagram of the flow of information to the control unit;
FIG. 8 is a schematic view of a heliostat calibration system of embodiment 2;
FIG. 9 is a schematic diagram of the heliostat calibration system of embodiment 3;
fig. 10 is a schematic diagram of the heliostat calibration system of embodiment 4.
The reference numbers in the figures denote:
1-receiver 2-heliostat 3-image sensor 4-mounting bracket 5-dimming device 6-sunlight source 7-fixed mounting bracket 8-rotary mounting bracket 9-supporting tower 10-plane mounting bracket 12-sight day tracking sensor 13-light intensity sensor 14, 14' -motor 15-cooling device 51-dimming disc 52-shading device
Detailed Description
The invention will be further elucidated below using the following examples in conjunction with the drawing.
Example 1
FIG. 2 shows a heliostat alignment system for a solar power plant comprising a receiver 1 mounted on a support tower 9, said receiver 1 receiving sunlight reflected by heliostats 2 to directly generate steam or electricity; the height of the receiver 1 from the ground ensures that all heliostats 2 in the heliostat field are reflected onto the receiver 1.
Further comprising a field of heliostats mounted around the receiver; the heliostat field comprises at least one heliostat 2; the heliostat 2 is provided with two rotating shafts, and the heliostat 2 performs pitching rotation and panning rotation around the rotating shafts; the dual rotary shafts are provided with angle sensors for accurately determining the actual pitch angle through which the two rotary shafts rotateAnd a pan angle ω. The heliostat 2 tracks the moving sun by adjusting the mirror orientation so that sunlight is continuously reflected onto the receiver 1.
And an image sensor group for capturing the reflected light spots of the calibration light source on the heliostat 2, the image sensor group comprising at least one image sensor 3. The image acquisition range of the image sensor 3 is larger than the reflection range of the heliostat field. Which collects the reflected light spots of heliostats that do not impinge on the receiver 1. The calibration light source in this embodiment is a sunlight light source 6. As another embodiment, the calibration light source may also be an artificial light source, which may be disposed on the receiver 1 or the image sensor 3.
The image sensor 3 is a camera mounted on a mounting bracket 4 located between the receiver 1 and the heliostat field. As shown in fig. 4, the image sensors are divided into a, b, c and d4 groups, 4 image sensors are arranged around the circumference of the receiver 1, the collecting surface of the image sensor 3 is arranged facing the receiver 1, and 4 image sensors respectively move up and down along the mounting bracket 4. The four groups of sensors a, b, c and d correspond to heliostats in the four areas of 3, 4, 1 and 2 respectively. The heliostats within the four zones are calibrated by the respective movement of the 4 image sensor groups. When the image sensor moves, the image sensor on the receiver 1 is shielded by the receiver 1, so that light spots of the heliostat irradiating the receiver 1 cannot be collected, and the image sensor 3 can only collect light spots reflected by the heliostat, which do not irradiate the receiver 1. In the present embodiment, the image sensor group is provided with a light reduction device 5 for reducing light intensity; the light reducing means 5 is a combination of light reflecting means and light absorbing means for protecting the image sensor group from strong light. The dimming degree of the dimming device 5 in this embodiment is variable, as shown in fig. 5, the dimming device 5 includes a dimming disc 51, which is disposed in front of the image sensor 3 and is divided into 6 blocks along the circumferential direction, the dimming ratio of each block is different, when the light intensity sensor 13 detects that the light intensity is strong, the motor 14 is controlled to rotate the dimming device 5 to the block with high dimming ratio, and when the light intensity sensor 13 detects that the light intensity is weak, the motor 14 is controlled to rotate the dimming device 5 to the block with low dimming ratio.
More preferably, a light shielding device 52 coaxial with the dimming disc 51 can be arranged in front of the dimming disc 51, as shown in fig. 6. The shade 52 is provided with a light-passing hole to allow all sunlight to pass through, and the other part shades all sunlight. In operation, the motor 14' drives the shutter 52 to rotate continuously, asynchronously with the dimming disc 51, and the image sensor completes the acquisition when the light-passing hole is aligned with the image sensor. The shutter 52 can reduce the exposure time, further reducing the effect of glare on the image sensor.
The image sensor group is further provided with a cooling device 15, which is an air or water cooling device for avoiding damage to the image sensors passing the receiver due to thermal radiation.
The calibration system also includes a sun tracking sensor 12 for tracking the position of the sun in real time to obtain the sun ray vector.
The calibration system further comprises a position sensor arranged on the moving track of the image sensor group and used for determining the positions of the receiver and the image sensor.
The calibration system also includes a control unit. As shown in fig. 7, the control unit receives heliostat image information collected by the image sensor group, position information of the image sensor 3 collected by the position sensor, sunlight position information collected by the sun tracking sensor 12, and rotation angle information of the heliostat 2 collected by the angle sensor; and controls the movement of the image sensor 3 and the rotation of the heliostat 2. When the control unit controls the heliostat 2 to rotate, so that the reflecting light spot of the heliostat is aligned to the receiver, the image sensor group 3 collects the image of the reflecting light spot of the heliostat which is not irradiated on the receiver 1, and the control unit determines the central position of the light spot reflected by the heliostat 2 according to the image information collected by the image sensor group and calibrates the heliostat 2 which is not aligned to the receiver 1.
And the control unit obtains the central position of the light spot reflected by the heliostat through the continuous movement of the image sensor group. When the serial image sensor group moves from one end of the guide rail to the other end at a constant speed for 30t, a two-dimensional graph shown in fig. 3 can be obtained, which reflects the situation of the image sensor capable of capturing the reflected light spot in the whole time period. The spatial position of the center of the reflected spot, i.e. the centroid position of the spot pattern, can be derived from this map.
The calibration system obtains the rotation angle of the heliostat by means of an angle sensor mounted on the rotation axis of the heliostat, i.e. by means of the pitch angleAnd (4) leveling the information of the rocking angle omega, and further obtaining an error value required to be calibrated by the heliostat. Wherein the pitch angle of the heliostatThe rotation angle of the heliostat about an axis parallel to the horizontal plane, and the pan angle ω of the heliostat is the rotation angle of the heliostat about an axis perpendicular to the horizontal plane.
When calibrating the heliostat, firstly, determining an error that needs to be calibrated, where the error that needs to be calibrated in this embodiment is: pitch and yaw anglesNon-perpendicularity eta of two rotating shafts0The spatial position (x, y, z) of the center o of the heliostat mirror, and the three Euler angles (α) of the heliostat's own coordinate system relative to the global coordinate system0，β0，γ0). In other embodiments, more error parameters may be introduced to improve calibration accuracy.
Wherein the pitch angle of the heliostatThe rotation angle of the heliostat around an axis parallel to the horizontal plane is shown, the panning angle omega of the heliostat is shown as the rotation angle of the heliostat around an axis vertical to the horizontal plane, the central position of the heliostat is shown as the position coordinates (x, y, z) of the center of the mirror surface of the heliostat, and the non-perpendicularity error of the rotating shaft is the actual included angle value of the two rotating shafts. Euler angle (alpha)0，β0，γ0) Three coordinate axes of the heliostat self coordinate system relative to the global coordinate systemThe declination angle of (c).
According to the error of the required calibration, the calibration method of the heliostat calibration system comprises the following steps:
a. the control unit controls the heliostat to rotate so that a reflection light spot of the heliostat is aligned to the receiver;
b. the image sensor group moves for the first time from the upper part of the receiver to the lower part of the receiver, the image sensor group detects light spots reflected by the heliostats, the control unit determines the central position of the light spots of the heliostats which are not aligned with the receiver, and the pitch angle and the yaw angle of the heliostats are obtained at the same time;
c. the control unit controls the heliostat to rotate, so that a reflection light spot of the heliostat reaches a position which can be detected by the image sensor;
d. repeating the steps b-c for 5 times to obtain 5 groups of light spot central positions and heliostat pitch angle and pan angle numerical values;
e. calculating the error value of the required calibration by an error calibration formula according to the 5 groups of data: pitch angle error, yaw angle error, rotation non-perpendicularity error, heliostat center position error and euler rotation angle error, and storing the error values to the control unit.
The error calibration formula is as follows:
wherein omega is a horizontal rocking angle of the heliostat rotating around the rotating shaft;
a pitch angle at which the heliostat rotates about the rotation axis;
is a unit vector perpendicular to the horizontal plane;
is the sunlight ray vector;
k is the coordinate of the central position of the light spot;
and o is the coordinate of the central position of the heliostat mirror surface.
In the step a, when the light spot acquired by the image sensor 3 is a partial light spot, the control unit calculates an area value A according to the obtained partial light spot profile; and (4) calculating a corresponding heliostat, then calculating the area A0 value of the reflected light spot according to the registered position of the heliostat to obtain the area value of the residual light spot as A0-A, and complementing the profile of the residual light spot in a rectangular or polygonal mode. And finally, calculating the geometric centroid of the addition graph of the partial light spot outline and the complementary area, and controlling the heliostat to rotate by the control unit so that the whole light spot falls on the position which can be captured by the image sensor group.
In order to improve the calibration precision, the steps a-b can be repeated for more times to obtain more groups of light spot central positions and heliostat pitch angle and pan angle numerical values, and the error value to be calibrated is calculated through an error calibration formula according to the groups of data.
Example 2
Fig. 8 shows a heliostat calibration system of the present embodiment, which is different from the calibration system of embodiment 1 in that: the heliostat field in this embodiment is located on one side of the receiver 1. The image sensor group is fixedly mounted on a fixed mounting bracket 7 around the receiver 1. The collection range is all heliostat reflective light spots which do not irradiate the receiver 1. The image sensors are uniformly distributed on the fixed mounting bracket 7, and in the embodiment, the image sensors are uniformly distributed along the longitudinal direction and the transverse direction.
When errors of the heliostat are small, the errors of the pitch angle and the yaw angle of the heliostat only need to be calibrated. In this embodiment, the error to be calibrated is: pitch angle and yaw angle of heliostatError, the calibration process of the heliostat calibration system comprising the steps of:
a. the control unit controls the heliostat to rotate so that a reflection light spot of the heliostat is aligned to the receiver;
b. the image sensor group collects images of the heliostat which do not irradiate on the receiver, and the control unit determines the central position of a light spot of the heliostat and obtains a pitch angle and a pan angle of the heliostat at the same time;
c. the control unit controls the heliostat to rotate, so that a reflection light spot of the heliostat reaches a position which can be detected by the image sensor;
d. from the above 1 set of data, the error value of the required calibration is calculated by the calibration formula described in example 1: pitch angle error, yaw angle error, and store the calibrated error value to the control unit.
Wherein the Euler angle (alpha)0，β0，γ0) Of the correction error value, the spatial position (x, y, z) of the center o of the heliostat mirror and the non-perpendicularity η of the two axes of rotation0The calibration error value invokes a stored value in the control unit.
The calibration error in this embodiment is obtained from 1 set of spot position data obtained by the image sensor and the pitch angle and yaw angle data of the heliostat. However, those skilled in the art should readily appreciate that the calibration error may also be derived from spot position data obtained by the sensor multiple times and pitch and yaw data of the heliostat for higher calibration accuracy.
Example 3
Fig. 9 is a heliostat calibration system in the present embodiment, which is substantially identical to the calibration system of embodiment 1, except that: the image sensor 3 can be installed on a rotary mounting bracket 8 in a vertically movable manner, the image sensor 3 is arranged along the horizontal direction, the acquisition surface of the image sensor faces the receiver 1, and the rotary mounting bracket 8 can rotate around a supporting tower 9 of the receiver. And the control unit obtains the central position of the light spot reflected by the heliostat through the up-and-down movement and the rotation of the image sensor group.
The heliostat is provided with two rotating shafts X and Y which are parallel to the horizontal plane, and the heliostat respectively rotates around the two rotating shafts in a pitching way; the two rotating shafts are respectively provided with an angle sensor for accurately measuring the rotating pitch angles of the two rotating shafts.
In this embodiment, the error to be calibrated is: pitch and yaw anglesNon-perpendicularity eta of two rotating shafts0The spatial position (x, y, z) of the center o of the heliostat mirror, and the three Euler angles (α) of the heliostat's own coordinate system relative to the global coordinate system0，β0，γ0). The calibration process of the heliostat calibration system comprises the following steps:
a. the control unit controls the heliostat to rotate so that a reflection light spot of the heliostat is aligned to the receiver;
b. the image sensor group moves for the first time from the upper part of the receiver to the lower part of the receiver after rotating 1/4 circles along the supporting tower, the image sensor group detects light spots reflected by heliostats facing to the image sensor group, and the control unit determines the center position of the light spots of the heliostats not aligned to the receiver and obtains the pitch angle and the yaw angle of the heliostats at the same time;
c. the control unit controls the heliostat to rotate in the area, so that a reflection light spot of the heliostat reaches a position which can be detected by the image sensor;
d. repeating steps a-b 9 times to obtain 9 sets of data, and calculating the error value of the required calibration according to the calibration formula described in example 1: pitch angle error, pan angle error, non-perpendicularity error of the rotating shaft, spatial position error of the heliostat mirror surface center o, and euler rotation angle error, and storing the calibrated error value to the control unit.
Wherein, the error calibration formula is as follows:
wherein,a pitch angle for rotation of the heliostat about the X-axis;
a pitch angle for rotation of the heliostat about the Y axis;
is a unit vector perpendicular to the horizontal plane;
is the sunlight ray vector;
k is the coordinate of the central position of the light spot;
and o is the coordinate of the central position of the heliostat mirror surface.
In this way, the calibration of heliostats in the area subtended by the image sensor is achieved; and when heliostats in other directions need to be calibrated, continuing to rotate the image sensor to repeat the calibration steps.
Example 4
Fig. 8 is a calibration system in the present embodiment, which is substantially identical to the calibration system in embodiment 2, and the difference is that: the image sensors 3 of this embodiment are mounted on a planar mounting support 10 located between the heliostat field and the receiver 1, and the image sensor groups are respectively located on the upper side and the lower side of the receiver 1, and on the left and right sides of the receiver 1, and are all arranged along the horizontal direction and move up and down along the planar mounting support 10.
In this embodiment, the moving mode of the image sensor group is intermittent movement at a certain time interval, and the heliostat field reflection light spot can be obtained in this moving mode when the image sensor group stops, so that the imaging quality is high. Meanwhile, the intermittent movement can conveniently adjust the dimming rate of the dimming device.
The calibration method of the heliostat in this embodiment is the same as that in embodiment 1.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (14)
1. A heliostat calibration system of a solar power plant, comprising: a receiver (1), the receiver (1) being for receiving sunlight reflected by a heliostat;
heliostat field consisting of at least one heliostat (2): mounted around the receiver;
an image sensor group of at least one image sensor (3): the heliostat is used for collecting a calibration light source reflection image of the heliostat;
and a control unit: the heliostat control system is used for processing image information obtained by the image sensor group, calibrating parameters of a heliostat for tracking the sun and controlling the rotation of the heliostat; the method is characterized in that:
the image sensor is arranged on the heliostat field in a vertically moving or horizontally moving or rotating manner, so that the reflected image of the heliostat reflected to the outside of the receiver (1) falls into the acquisition range of the image sensor group; the calibration light source reflection image of the heliostat collected by the image sensor group is a spot and is used for obtaining the outline of a reflection light spot of the heliostat; when the control unit controls the heliostat (2) to rotate, so that a reflecting light spot of the heliostat is aligned to a receiver, the image sensor group (3) collects images of the reflecting light spot of the heliostat by moving up and down, left and right or rotating, the control unit determines the central position of the light spot reflected by the heliostat (2) according to image information collected by the image sensor group, and calibrates the heliostat (2); the image sensor (3) is movably mounted on a mounting bracket (4) positioned between the receiver (1) and the heliostat field, the image sensor (3) surrounds the circumference of the receiver (1), the acquisition surface of the image sensor (3) is arranged facing the receiver (1), and the image sensor moves up and down along the mounting bracket (4); or the image sensors (3) can be arranged on a rotary mounting bracket (8) in a vertically moving mode, the image sensors (3) are arranged along the horizontal direction, the acquisition surfaces of the image sensors face the receiver (1), and the rotary mounting bracket (8) can rotate around a supporting tower (9) of the receiver; or the image sensor group and the heliostat field are respectively arranged at two opposite sides of the receiver (1), the image sensor (3) is movably arranged on a plane mounting bracket (10), and the image sensor group is arranged along the horizontal or vertical direction and moves up and down or left and right along the plane mounting bracket (10).
2. Heliostat calibration system of a solar power plant according to claim 1, characterized in that:
the image sensor group is provided with a light reducing means (5) for reducing the light intensity, said light reducing means (5) comprising a reflecting means of light and/or an absorbing means of light.
3. Heliostat calibration system of a solar power plant according to claim 2, characterized in that:
the dimming device is a dimming device (5) capable of adjusting dimming intensity.
4. Heliostat calibration system of a solar power plant according to claim 3, characterized in that:
the image sensor group is provided with a light blocking device (52) for blocking sunlight.
5. Heliostat calibration system of a solar power plant according to claim 4, characterized in that:
the image sensor group is provided with a light intensity sensor (13) for measuring light intensity.
6. Heliostat calibration system of a solar power plant according to claim 5, characterized in that:
the image sensor group is provided with a cooling device which is an air cooling device or a water cooling device.
7. Heliostat calibration system of a solar power plant according to claim 6, characterized in that:
the heliostat is provided with two rotating shafts, and the heliostat performs pitching rotation and panning rotation around the rotating shafts; the two rotary shafts are provided with angle sensors for accurately measuring the actual angle through which the two rotary shafts rotate.
8. Heliostat calibration system of a solar power plant according to claim 6, characterized in that:
the heliostat is provided with two rotating shafts, and the heliostat respectively rotates around the two rotating shafts in a pitching manner; the two rotary shafts are provided with angle sensors for accurately measuring the actual angle through which the two rotary shafts rotate.
9. Heliostat calibration system of a solar power plant according to claim 1, characterized in that:
the calibration system also includes a sun tracking sensor (12) for tracking the position of the sun in real time.
10. Heliostat calibration system of a solar power plant according to claim 1, characterized in that:
the calibration system further comprises a position sensor arranged on the moving track of the image sensor group and used for determining the positions of the receiver and the image sensor.
11. Heliostat calibration system of a solar power plant according to claim 1, characterized in that:
the calibration light source is a sunlight light source (6) or an artificial light source.
12. A method of calibrating a heliostat calibration system of a solar power plant of any of claims 1 to 11, characterized in that:
the method comprises the following steps:
a. the control unit controls the heliostat to rotate so that a reflection light spot of the heliostat is aligned to the receiver;
b. the control unit determines the central position of a light spot reflected by the heliostat and the corresponding heliostat according to the image collected by the image sensor group, and obtains the rotation angle of the heliostat through the measurement value of an angle sensor or the command of the control unit;
c. the control unit controls the heliostat to rotate, so that a reflection light spot of the heliostat reaches a position which can be detected by the image sensor;
d. repeating the steps b-c for at least n/2 times according to the number n of error values to be calibrated;
e. and calculating an error value required to be calibrated according to the obtained light spot center position and the rotation angle information of the heliostat, and storing the calibrated error value to the control unit.
13. Method for calibrating a heliostat calibration system of a solar power station according to claim 12, characterized in that:
and b, collecting the reflection image of the heliostat by the image sensor group in a mode of moving up and down, or moving left and right, or rotating and moving, so that the reflection image of the heliostat reflected to the outside of the receiver (1) falls into the collection range of the image sensor group.
14. Method for calibrating a heliostat calibration system of a solar power station according to claim 12, characterized in that: and c, when the light spots acquired by the image sensor in the step b are partial light spots, the control unit controls the heliostat to rotate so that the whole light spot falls on a position which can be captured by the image sensor group.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110303115.4A CN102354226B (en) | 2011-09-29 | 2011-09-29 | Heliostat calibration system of solar power station and calibration method |
| PCT/CN2012/082326 WO2013044849A1 (en) | 2011-09-29 | 2012-09-28 | Heliostat calibration system and calibration method of solar power station |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110303115.4A CN102354226B (en) | 2011-09-29 | 2011-09-29 | Heliostat calibration system of solar power station and calibration method |
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| Publication Number | Publication Date |
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| CN102354226A CN102354226A (en) | 2012-02-15 |
| CN102354226B true CN102354226B (en) | 2014-09-24 |
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| CN201110303115.4A Expired - Fee Related CN102354226B (en) | 2011-09-29 | 2011-09-29 | Heliostat calibration system of solar power station and calibration method |
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| CN (1) | CN102354226B (en) |
| WO (1) | WO2013044849A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105022410A (en) * | 2015-05-07 | 2015-11-04 | 浙江中控太阳能技术有限公司 | System and method for calibrating heliostat of tower solar power generation system |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102354226B (en) * | 2011-09-29 | 2014-09-24 | 深圳市联讯创新工场科技开发有限公司 | Heliostat calibration system of solar power station and calibration method |
| CN108413987B (en) * | 2018-03-13 | 2021-03-26 | 深圳中科能投能源有限公司 | Heliostat calibration method, device and system |
| CN108958229B (en) * | 2018-08-24 | 2024-05-17 | 首航高科能源技术股份有限公司 | Method and device for rapidly and qualitatively detecting tracking accuracy of heliostat |
| CN109813754B (en) * | 2019-02-14 | 2022-06-28 | 浙江可胜技术股份有限公司 | System and method for measuring and optimizing heat absorber truncation efficiency |
| US11009263B2 (en) * | 2019-02-25 | 2021-05-18 | Karl von Kries | Systems and methods for altering rotation of a solar rotational manufacturing system |
| CN117664534B (en) * | 2024-01-31 | 2024-04-16 | 山东电力建设第三工程有限公司 | Grouping BCS (binary coded decimal) targeting verification method for tower type photo-thermal mirror field |
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- 2011-09-29 CN CN201110303115.4A patent/CN102354226B/en not_active Expired - Fee Related
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Also Published As
| Publication number | Publication date |
|---|---|
| WO2013044849A1 (en) | 2013-04-04 |
| CN102354226A (en) | 2012-02-15 |
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