Receiver position adjustment device and method for compensating optical errors of a dish concentrator system

Abstract

The application discloses a kind of dish type concentrating system optical error compensation receiver position adjusting device, including condensing device, cavity receiver, position adjusting device, light spot receiving device, camera assembly, image processor and controller;The position adjusting device is two-dimensional position adjusting platform by linear guide rail I and linear guide rail II that are mutually orthogonal, cavity receiver is installed on its sliding table II;Through rotatable plane receiving target in light spot receiving device cooperate CCD camera fast measurement condensing device focusing light spot image, and after processing its energy centroid coordinates feedback to controller to control the position adjustment of cavity receiver on sliding table II, make the central axis of cavity receiver adjust to the centroid position of focusing light spot, substantially improve the circumferential energy uniformity of cavity receiver and reduce energy flow density peak, avoid high temperature hot spot ablation and other problems.The application also discloses a kind of dish type concentrating system optical error compensation receiver position adjusting method.

Description

Technical Field

[0001] This invention belongs to the field of solar concentrated thermal power generation, and in particular to a receiver position adjustment device and position adjustment method for optical error compensation in a dish-type concentrator system. Background Technology

[0002] Solar energy is a clean, environmentally friendly, and widely distributed renewable energy source. The technology typically involves using a large-area reflective concentrator to focus low-density solar energy into a small cavity heat receiver. This heat is absorbed by an absorber within the receiver, heating the heat transfer medium in the absorber's flow channels. This conversion of solar energy into heat energy in the heat transfer medium allows for external heating or the use of this medium to drive a heat engine (steam turbine or Stirling engine) to generate electricity. A dish concentrator system is a solar thermal collection device consisting of a parabolic dish concentrator and a cavity receiver, and is a crucial component for achieving high-temperature solar heating or dish / Stirling solar thermal power generation systems.

[0003] Solar thermal receivers are always the core device in the field of solar thermal utilization. To reduce optical and thermal losses, cavity-structure receivers are typically used. In high-concentration solar thermal utilization, metal coils are widely used as heat absorbers in solar thermal receivers. These are made by coiling or bending metal tubes into a cavity structure; for example, a cylindrical cavity receiver is usually made of copper tubing coiled in a spiral shape and then wrapped with insulation material. In existing technologies, cavity receivers are generally fixed near the focal point of a dish concentrator, and their position is not adjustable during operation. Due to structural deformation caused by external loads such as self-weight and wind loads during operation of the dish concentrator system, and the accumulation of transmission errors during the operation of the dual-axis tracking device leading to solar tracking errors in the concentrator, these errors collectively alter the energy flux density distribution absorbed on the internal surface of the cavity receiver. This results in the formation of significant high-temperature hot spots in some locations. Furthermore, the uneven circumferential energy distribution creates uneven driving forces for the four-cylinder Stirling engine, potentially reducing the overall system efficiency. The extremely high temperatures in these localized high-energy flux peak areas on the receiver surface could burn through the absorber walls, leading to safety hazards. Therefore, it is crucial to invent a device and method that measures the actual focused spot position and rationally adjusts the cavity receiver position to adapt to the complex changes in the focused energy flux distribution during the operation of the dish concentrator system, achieving safe, reliable, and efficient light-to-heat conversion. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a receiver position adjustment device and method for optical error compensation in a dish-type focusing system, which has the advantages of simple structure and excellent improvement effect.

[0005] The technical solution adopted in this invention is: a receiver position adjustment device for optical error compensation in a dish-type concentrator system, comprising a concentrator that tracks the sun's position and focuses sunlight through a mirror, and a cavity receiver installed near the focal point of the concentrator to absorb and concentrate the sunlight energy; it also includes a position adjustment device, a light spot receiving device, a camera assembly, an image processor, and a controller; the position adjustment device includes a base fixed to the support truss of the concentrator, a linear guide rail I with a lead screw driven fixed to the base and parallel to the ground plane, a slide rail arranged parallel to the linear guide rail I, two slide tables I respectively cooperating with the linear guide rail I and the slide rail, a linear guide rail II with a lead screw driven fixed to the two slide tables I and perpendicular to the linear guide rail I, a slide table II cooperating with the linear guide rail II, a motor I that drives the lead screw of the linear guide rail I to move the slide table I, and a motor II that drives the lead screw of the linear guide rail II to move the slide table II; the cavity receiver is fixed to the slide table by a bottom flange. The cavity receiver is located at the front end of the slide II and its front opening faces the mirror of the focusing device. The opening plane of the cavity is perpendicular to the focal axis of the focusing device. The light spot receiving device includes a square planar receiving target, point light sources fixed at the four corners of the planar receiving target and facing the mirror of the focusing device, a rotating shaft eccentrically fixed to the back of the planar receiving target and cooperating with the bearing on the base, and a motor III fixed to the end of the rotating shaft and driving the rotating shaft to rotate. The planar receiving target is located at the front end of the cavity receiver and parallel to its cavity opening plane. The side of the planar receiving target facing the mirror of the focusing device is a Lambertian surface. The camera assembly includes a CCD camera fixed to the focusing device and capturing images of the focused light spot on the planar receiving target, and a neutral density filter installed in front of the CCD camera lens. The CCD camera captures images of the focused light spot on the planar receiving target and transmits them to the image processor to calculate the position of the energy centroid of the focused light spot, and then feeds it back to the controller to control motor I and motor II to adjust the position of the cavity receiver on slide II.

[0006] In the aforementioned receiver position adjustment device for optical error compensation in a dish-type concentrator system, the light spot receiving device further includes a storage box with a rectangular cavity and openings on adjacent sides. The storage box is located on one side of the cavity receiver. When the planar receiving target is not in the condition of receiving the focused light spot, the planar receiving target rotates into the storage box without blocking the absorption and convergence of solar energy by the cavity receiver. When the planar receiving target rotates from the storage box to the condition of receiving the focused light spot, the center of the planar receiving target is located on the focal axis of the concentrator, and the bottom edge of the planar receiving target is parallel to the linear guide rail I.

[0007] In the aforementioned receiver position adjustment device for optical error compensation in a dish-type focusing system, the point light source is a laser light source with controllable brightness, and its brightness adjustment is controlled by a controller; heat insulation material is provided in the fixed connection between the bottom flange of the cavity receiver and the slide II.

[0008] In the aforementioned receiver position adjustment device for optical error compensation in a dish-type focusing system, the camera assembly further includes a waterproof and moisture-proof protective cover for the CCD camera and the neutral density filter.

[0009] In the aforementioned receiver position adjustment device for optical error compensation in a dish-type focusing system, the cavity receiver further includes several temperature sensors arranged around its circumference, and the temperature information is transmitted to the controller.

[0010] A receiver position adjustment method for optical error compensation in a dish-type focusing system includes the following steps:

[0011] 1) Taking the center of the planar receiving target as the origin O of the global coordinate system when it is receiving and focusing the light spot, establish parallel coordinate systems along its two adjacent sides. x and y Axis; Set the actual coordinate values ​​of the four point light sources on the planar receiving target; Calibrate the coordinate relationship between the position adjustment device and the planar receiving target; Set the circumferential temperature difference threshold T of the cavity receiver and the focusing spot measurement time interval t;

[0012] 2) The planar receiving target is in the storage state, and the cavity receiver absorbs the solar energy gathered by the concentrating device, and is in the concentrating and heat collection operation mode; the temperature sensor arranged around the cavity receiver measures the temperature in real time. When the circumferential temperature difference is greater than the threshold T or the time since the last focused spot measurement is greater than t, the process proceeds to step 3.

[0013] 3) The planar receiving target is rapidly rotated from the receiving box to the working position of the focused light spot. At this time, the CCD camera quickly acquires the focused light spot image and transmits it to the image processor. Then, the planar receiving target is quickly rotated back into the receiving box. The focused light spot image is converted into a grayscale image, and the center points of the four point light sources are extracted to determine the coordinate system O. -xy The position, then with O -xy Calculate the weighted centroid of the grayscale values ​​in the focused spot image using a coordinate system. x and y Coordinate values, then centroid x and y The coordinate values ​​are fed back to the controller to control motor I and motor II to adjust the position of the cavity receiver on slide II, so that the central axis of the cavity receiver is adjusted to the centroid of the focused light spot; finally, the process proceeds to step 2 to operate in the concentrating and heat collection mode.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] This invention provides a receiver position adjustment device and method for optical error compensation in a dish-type concentrator system. It features simple structure, convenient measurement, long-term monitoring, and excellent energy flux distribution improvement. By mounting the cavity receiver on a cross-shaped linear guide platform, the receiver's position can be adjusted in a two-dimensional plane. A rotatable planar receiving target, in conjunction with a CCD camera, rapidly measures the focused spot image of the concentrator during actual service, processes its energy centroid coordinates, and then feeds these coordinates back to the controller to control motors I and II. This adjusts the position of the cavity receiver on slide II, aligning its central axis with the centroid of the focused spot. This significantly improves the uniformity of energy distribution on the inner circumferential surface of the cavity receiver and effectively reduces peak energy flux density, avoiding problems such as high-temperature hot spot erosion. This invention can flexibly and effectively improve the concentrating performance of dish-type concentrator systems, achieving safe, reliable, and efficient light energy concentration and subsequent light-to-thermal conversion. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the receiver position adjustment device for optical error compensation in the dish-type focusing system of the present invention.

[0017] Figure 2 This is an isometric view of the receiver position adjustment device and the planar receiving target in the receiving focused spot state in this invention.

[0018] Figure 3 This is an isometric view of the planar receiving target in the stored state in this invention.

[0019] Figure 4 The present invention provides a receiver position adjustment method and its flowchart.

[0020] In the diagram: 1-Concentrating device; 101-Azimuth-Pitch dual-axis tracking device; 102-Concentrator; 103-Supporting column; 104-Supporting truss; 2-Camera assembly; 3-Image processor; 4-Controller; 5-Spot receiving device; 501-Point light source; 502-Planar receiving target; 503-Rotating shaft; 504-Motor III; 505-Storage box; 6-Cavity receiver; 7-Position adjustment device; 701-Base; 702-Motor I; 703-Linear guide rail I; 704-Slide table I; 705-Linear guide rail II; 706-Slide table II; 707-Motor II; 708-Slide rail. Detailed Implementation

[0021] The invention will now be further described with reference to the accompanying drawings.

[0022] like Figures 1-3As shown, the receiver position adjustment device for optical error compensation in the dish-type concentrator system of the present invention includes a concentrator 1 that tracks the position of the sun and concentrates sunlight through a mirror, and a cavity receiver 6 installed near the focal point of the concentrator 1 to absorb and concentrate the sunlight energy. The concentrator 1 includes a concentrator 102 employing a parabolic reflector, a support truss 104 fixedly connected at one end to a central fixed body of the concentrator 102, a support column 103 fixed to the foundation, and an azimuth-pitch dual-axis tracking device 101 installed on top of the support column 103. It also includes a position adjustment device 7, a light spot receiving device 5, a camera assembly 2, an image processor 3, and a controller 4; the position adjustment device 7 includes a base 701 fixed to the support truss 104 of the focusing device 1, a linear guide rail I 703 with a lead screw drive fixed to the base 701 and parallel to the ground plane, a slide rail 708 located below the linear guide rail I 703 and arranged in parallel, two slide tables I 704 that respectively cooperate with the linear guide rail I 703 and the slide rail 708, wherein the slide table I 704 that cooperates with the linear guide rail I 703 has a threaded pair, a linear guide rail II 705 with a lead screw drive fixed to the two slide tables I 704 and perpendicular to the linear guide rail I 703, a slide table II 706 that cooperates with the linear guide rail II 705, and a motor I that drives the lead screw of the linear guide rail I 703 to drive the slide table I 704. 702. A motor II 707 drives the linear guide II 705 via a lead screw to move the slide II 706. The cavity receiver 6 is fixed to the slide II 705 via a bottom flange, with its front opening facing the reflector of the focusing device 1. The plane of this cavity opening is perpendicular to the focal axis of the focusing device 1, i.e., parallel to the focal plane of the focusing device 1. The light spot receiving device 5 includes a square planar receiving target 502, point light sources 501 fixed at the four corners of the planar receiving target 502 and facing the reflector of the focusing device 1, a rotating shaft 503 eccentrically fixed to the back of the planar receiving target 502 and engaged with a bearing on the base 701, and a motor III fixed to the end of the rotating shaft 503 and driving the rotating shaft 503 to rotate. 504; The planar receiving target 502 is located at the front end of the cavity receiver 6 and is parallel to its cavity opening plane. The side of the planar receiving target 502 facing the reflective mirror of the focusing device 1 is a Lambertian surface. The camera assembly 2 includes a CCD camera fixed on the focusing device 1 and capturing images of the focused spot on the planar receiving target 502, and a neutral density filter installed in front of the CCD camera lens. The CCD camera acquires images of the focused spot on the planar receiving target 502 and transmits them to the image processor 3 to calculate the position of the energy centroid of the focused spot. Then, it feeds back to the controller 4 to control the motor I 702 and the motor II 707 to adjust the position of the cavity receiver 6 on the slide II 706.

[0023] like Figure 2 and Figure 3As shown, the light spot receiving device 5 also includes a storage box 505 with a rectangular cavity and openings on adjacent sides, the storage box 505 being located on one side of the cavity receiver 6. Figure 3 As shown, when the planar receiving target 502 is not in the condition of receiving focused light spot, the planar receiving target 502 rotates into the storage box 505 and does not block the absorption and convergence of solar energy by the cavity receiver 6; as Figure 4 As shown, when the planar receiving target 502 rotates from the storage box 505 to the condition of receiving the focused light spot, the center of the planar receiving target 502 is located on the focal axis of the focusing device 1, and the bottom edge of the planar receiving target 502 is parallel to the linear guide rail I 702.

[0024] The point light source 501 is a laser light source with controllable brightness, and its brightness adjustment is controlled by the controller 4; the bottom flange of the cavity receiver 6 is provided with heat insulation material in the fixed connection between it and the slide II 706; the camera assembly 2 also includes a waterproof and moisture-proof protective cover for the CCD camera and the neutral density filter; the cavity receiver 6 also includes several temperature sensors arranged around its circumference, and the temperature information is transmitted to the controller 4.

[0025] like Figure 4 As shown, the receiver position adjustment method for optical error compensation in a dish-type focusing system of the present invention includes the following steps:

[0026] 1) Taking the center of the planar receiving target 502 as the origin O of the global coordinate system when it is receiving and focusing the light spot, establish parallel coordinate systems along its two adjacent sides. x and y Axis, such as Figure 2 As shown; set the actual coordinate values ​​of the four point light sources 501 on the planar receiving target 502; calibrate the coordinate relationship between the position adjustment device 7 and the planar receiving target 502; set the circumferential temperature difference threshold T and the focusing spot measurement time interval t of the cavity receiver 6;

[0027] 2) The planar receiving target 502 is in the storage state, and the cavity receiver 6 absorbs the solar energy gathered by the concentrating device 1 and is in the concentrating and heat collection operation mode; the temperature sensor arranged around the cavity receiver 6 measures the temperature in real time. When the circumferential temperature difference is greater than the threshold T or the time since the last focused spot measurement is greater than t, the process returns to step 3.

[0028] 3) The planar receiving target 502 is rapidly rotated from the storage box 505 to the working position of the focused light spot. At this time, the CCD camera quickly acquires the focused light spot image and transmits it to the image processor 3. Then, the planar receiving target 502 is quickly rotated into the storage box 505 without obstructing the light-to-heat conversion of the cavity receiver. The focused light spot image is converted into a grayscale image, and the center points of the four point light sources 501 are extracted to determine the coordinate system O. -xy The position, then with O -xy Calculate the weighted centroid of the grayscale values ​​in the focused spot image using a coordinate system. x and y Coordinate values, then centroid x and y The coordinate values ​​are fed back to the controller 4 to control the motor I 702 and the motor II 707 to adjust the position of the cavity receiver 6 on the slide II 706, so that the central axis of the cavity receiver 6 is adjusted to the centroid position of the focused light spot; finally, the process returns to step 2 to operate in the concentrating and heat collection mode.

Claims

1. A receiver position adjustment device for optical error compensation in a dish-type concentrator system, comprising a concentrator that tracks the sun's position and focuses sunlight through a mirror, and a cavity receiver installed near the focal point of the concentrator to absorb and focus the sunlight energy; characterized in that: It also includes position adjusting device, light spot receiving device, camera assembly, image processor and controller; the position adjusting device includes base fixed on support truss of light collecting device, linear guide rail I with screw rod drive fixed on base and parallel to ground plane, slide rail arranged below linear guide rail I and in parallel, two slide tables I matched with linear guide rail I and slide rail respectively, linear guide rail II with screw rod drive fixed on two slide tables I and vertical to linear guide rail I, slide table II matched with linear guide rail II, motor I driving screw rod of linear guide rail I to drive slide table I to move, motor II driving screw rod of linear guide rail II to drive slide table II to move; the cavity receiver is fixed on slide table II through bottom flange and the cavity front end opening thereof faces mirror surface of light collecting device, the opening plane of the cavity is vertical to focal axis of light collecting device; the light spot receiving device includes square plane receiving target, point light source fixed on four corner points of plane receiving target and facing mirror surface of light collecting device, rotating shaft eccentrically fixed on back of plane receiving target and matched with bearing on base, motor III fixed on end of rotating shaft and driving rotating shaft to rotate; the plane receiving target is located at front end of cavity receiver and parallel to cavity opening plane thereof, the side of plane receiving target facing mirror surface of light collecting device is Lambertian surface; the camera assembly includes CCD camera fixed on light collecting device and shooting focused light spot image on plane receiving target, neutral density filter installed in front of lens of CCD camera; the CCD camera collects focused light spot image on plane receiving target and transmits to image processor to calculate focused light spot energy centroid position, then feeds back to controller to control motor I and motor II to realize position adjustment of cavity receiver on slide table II.

2. The receiver position adjustment device for optical error compensation of a dish concentrator system according to claim 1, characterized in that: The light spot receiving device also includes receiving box with rectangular cavity and adjacent two side openings, the receiving box is located at one side of cavity receiver; when plane receiving target is in non-receiving focused light spot working condition, plane receiving target is rotated into the receiving box and does not block cavity receiver to absorb converged solar energy; when plane receiving target is rotated from receiving box to receiving focused light spot working condition, the center of plane receiving target is located on focal axis of light collecting device and the bottom edge of plane receiving target is parallel to linear guide rail I.

3. The receiver position adjustment device for optical error compensation of a dish concentrator system according to claim 1, characterized in that: The point light source is laser light source with controllable brightness, the brightness adjustment is controlled by controller; the fixed connection between bottom flange of cavity receiver and slide table II is provided with heat insulation material.

4. The receiver position adjustment apparatus for optical error compensation of a dish concentrator system according to claim 1, characterized by: The camera assembly also includes waterproof and moisture-proof protective cover for CCD camera and neutral density filter.

5. The receiver position adjustment apparatus for optical error compensation of a dish concentrator system according to claim 1, characterized by: The cavity receiver also includes several temperature sensors arranged in circumferential direction thereof, transmitting temperature information to controller.

6. A kind of dish type concentrating system optical error compensation receiver position adjusting method, comprising the following steps: 1) the center of the plane receiving target in the working condition of receiving the focused light spot is the origin O of the global coordinate system, and two parallel axes are established along the adjacent two sides of the plane receiving target x and y axis; set the actual coordinate values of the four point light sources on the plane receiving target; calibrate the coordinate relationship between the position adjusting device and the plane receiving target; set the threshold T of the circumferential temperature difference of the cavity receiver and the measurement time interval t of the focused light spot; 2) plane receiving target is in receiving state, cavity receiver absorbs solar energy gathered by light collecting device, in light collecting operation condition; temperature sensor arranged in circumferential direction of cavity receiver measures temperature in real time, when circumferential temperature difference is greater than threshold T or distance from last focused light spot measurement time is greater than t, turn to step 3; 3) The plane receiving target is quickly rotated from the storage box to the working position of receiving the focused light spot, at this time the CCD camera quickly collects the focused light spot image and transmits it to the image processor, and then quickly rotates the plane receiving target into the storage box; the focused light spot image is converted into a gray scale image, the center points of the four point light sources are extracted to determine the coordinate system O -xy 's position, and the x and y coordinate values of the weighted centroid of the gray scale value of the focused light spot image are calculated in the O -xy coordinate system, and then the centroid x and y coordinate values are fed back to the controller to control the motor I and the motor II to realize the position adjustment of the cavity receiver on the slide table II, so that the central axis of the cavity receiver is adjusted to the centroid position of the focused light spot; finally, step 2 is turned to run in the light collection and heat collection working condition.

Images