Device and method for testing wind-induced loss of concentration of heliostat

Abstract

The application discloses a heliostat wind-induced light loss testing device and method, and belongs to the technical field of solar energy application. The method comprises the following steps: solar position simulation and light path calibration, mirror field layout and target mirror-target surface space relationship construction, dynamic calculation and adjustment of the running posture of the heliostat, introduction of wind load and group interference effect, synchronous measurement of dynamic light spots under tower-mirror coupling vibration, and comprehensive analysis and decoupling of light loss. The device comprises a sun simulation subsystem, a mirror field and heat absorption tower simulation subsystem, a synchronous measurement and data acquisition subsystem, and an integrated control system and software. The application can reproduce real working conditions by coupling multiple elements, quantitatively decouple light loss caused by different factors, and provide data support for heliostat design optimization, control algorithm correction and operation and maintenance of a solar thermal power station, thereby effectively improving the light concentration efficiency and operation reliability of the power station.

Description

Technical Field

[0001] This invention relates to the field of solar energy application technology, and in particular to a device and method for testing wind-induced concentration loss of heliostats. Background Technology

[0002] Solar thermal power generation is a novel energy application technology with advantages such as low carbon footprint, cleanliness, continuous operation, strong energy storage, and grid regulation capabilities. A typical solar thermal power generation system uses heliostats to reflect and concentrate sunlight onto a collector at the top of an absorber tower. Inside the collector, molten salt circulates to absorb solar radiation and convert it into heat energy. This heat energy is then used to generate steam to drive a turbine for power generation. Therefore, the heliostat, as a crucial component in the photothermal conversion process, is vital to the solar thermal power generation system due to its reflection and concentration efficiency.

[0003] During operation, tower heliostats need to track the sun's trajectory, effectively and massively reflecting and concentrating sunlight onto the collector at the top of the receiver tower by adjusting the elevation and azimuth angles of the mirrors. However, concentrated solar power (CSP) plants are mostly built in barren, desert, and Gobi areas with little shading, low surface roughness, and wind environments characterized by high wind speeds, strong non-stationarity, and drastic wind direction changes. Simultaneously, due to the blunt body effect of the heliostat structure itself and the enhanced turbulence from the heliostat field and power plant structures, the heliostat and receiver tower are prone to deformation and vibration, leading to beam divergence, beam shift and vibration on the receiver, significantly reducing concentrating efficiency and beam quality, thus affecting the power generation efficiency and return on investment of the CSP plant. Therefore, in the early stages of CSP plant construction, targeted wind tunnel tests must be conducted to accurately obtain the wind-induced response and concentrating efficiency of the heliostat and receiver tower at the proposed site, serving as the basis for heliostat structural design, optical performance evaluation, operation and maintenance strategy formulation, and commercial operation of the project. However, existing technologies are mostly focused on studying the light-gathering efficiency of heliostats in windless conditions or under specific heliostat orientations, which has the following limitations: (1) The wind load test was not combined with the attitude adjustment of the heliostat as the sun position changed, making it difficult to reflect the wind-induced optical efficiency loss under different operating conditions in different seasons and at different times. (2) The influence of the upstream heliostat wake on the downstream heliostat wind field characteristics was not considered, and the interference effect of the mirror field caused by the changes in wind speed distribution and turbulent structure was ignored, resulting in an oversimplification of the assessment of the target mirror wind load and light concentration loss. (3) The coupling effect of the vibration of the heliostat and the heat absorption tower under wind load is not considered, and the dynamic change of the relative spatial position of the receiver is ignored, making it difficult to accurately assess the light concentration loss caused by wind-induced vibration. Summary of the Invention

[0004] The purpose of this invention is to provide a device and method for testing wind-induced light concentration loss of a heliostat, which comprehensively considers the relationship between actual operating time and attitude change, the interference effect of the mirror field, and the influence of coupled vibration of the heliostat in the heat-absorbing tower, so as to achieve a more accurate assessment of wind-induced light concentration loss.

[0005] To achieve the above objectives, this invention provides a method for testing wind-induced concentration loss of heliostats, applied to a wind tunnel testing system comprising a solar position simulation device, a concentration loss measurement device, a heliostat model group, and an absorber tower model, comprising the following steps: S1. Solar position simulation and initial optical path calibration: Based on the preset power station geographical location, test date and time, the solar position simulation module obtains the solar altitude angle and azimuth angle, drives the solar simulation subsystem to adjust the beam incident angle, and simulates the direction of sunlight at that moment; S2. Construction of the mirror field layout and target mirror-target surface spatial relationship: Based on the mirror field layout of the power station, a group of heliostat models are arranged in the wind tunnel test section and the elastic model of the heat-absorbing tower is positioned proportionally. The theoretical relative position between the target heliostat model and the top of the elastic model of the heat-absorbing tower is calculated according to the actual coordinates of the target heliostat model. The spatial coordinates of the composite optical target surface at the top of the elastic model of the heat-absorbing tower are adjusted to establish the initial "mirror-tower" optical path. S3. Dynamic calculation and adjustment of the heliostat's operating attitude: Combining the direction of sunlight simulated in S1 and the "mirror-tower" optical path constructed in S2, the elevation and azimuth angles required for the target heliostat model to reflect light to the center of the target surface are obtained through the heliostat attitude calculation module, and the target heliostat model is adjusted to this theoretical attitude. S4. Introducing wind load and group interference effect: A simulated wind field with specific wind speed, wind direction and turbulence intensity is generated in the wind tunnel, so that the wake generated by the upstream heliostat model acts on the downstream target heliostat model, and reproduces the group interference effect in the power station mirror field. S5. Synchronously measure the dynamic light spot under the coupled vibration of the tower-mirror, start the wind field and simultaneously act on the heliostat model group and the elastic model of the heat-absorbing tower. After the wind field stabilizes, the vibration displacement of the key points of the target heliostat mirror surface and the top target area of ​​the elastic model of the heat-absorbing tower is synchronously collected through the structural response measurement unit. At the same time, the position, shape and energy distribution of the reflected light spot on the dynamic target surface are synchronously collected at high frequency through the light concentration loss measurement device. S6: Comprehensive analysis and decoupling of focusing efficiency loss: Calculate instantaneous focusing efficiency and obtain efficiency loss based on collected dynamic spot data; quantify spot area cutoff efficiency, loss caused by mirror deformation and vibration, and additional loss caused by tower vibration through data correlation analysis; decouple the contribution of group interference; analyze the variation law of wind-induced loss under different solar altitude angles and establish a correlation database.

[0006] Preferably, in S1, the solar simulation subsystem includes a laser emitter, a sliding trolley, a lever mechanism, a drive motor, and a controller; in S2, the composite optical target surface is a composite target surface of a Lambertian diffuse screen, a position-sensitive detector (PSD), and a photodetector (PD) array. In S1, the specific workflow of the solar simulation subsystem is as follows: Based on the preset geographical location of the power station, the test date and time, the solar azimuth angle is calculated, and the sliding trolley is driven to move to the corresponding position on the pendulum mechanism; simultaneously, the solar altitude angle is calculated, and the pendulum mechanism is driven to rotate to the corresponding pitch angle; the calculation formula is as follows: Solar altitude angle: ; Sun azimuth: ; in, Local time angle; Geographic latitude; Solar declination angle; hour angle From true solar time Sure: .

[0007] Preferably, the specific content of S3 is: the solar simulation subsystem determines the unit vector of the incident direction of sunlight. According to the top coordinates of the heat absorption tower elastic model Coordinates of the heliostat model in the mirror field Based on the principle of light reflection, determine the unit vector of the reflection direction. Unit vector of normal direction of heliostat model The attitude of the heliostat model was calculated, and the elevation angle of the heliostat model was adjusted. and azimuth To establish a complete reflected light path, the calculation formula is as follows: ; ; ; ; in, These are the heliostat models in the mirror field. X coordinate, Y Coordinates, top height of the heat absorption tower elastic model; and These are the solar altitude angle and azimuth angle, respectively. and These are the elevation and azimuth angles of the heliostat model, respectively. and These are the unit vectors for the incident and reflected directions of sunlight, respectively.

[0008] Preferably, in S5, the structural response measurement unit is a laser displacement meter; the focusing loss measurement device is a PSD and PD array.

[0009] Preferably, in S6, the calculation methods for each loss are as follows: The instantaneous focusing efficiency is the ratio of the light energy reaching the effective receiving area of ​​the target surface to the total emitted light energy; the specific calculation process is as follows: Calculate the light spot at time and Towards absolute instantaneous displacement , : , ; In the formula, , Measured from PSD time and Displacement; and They are respectively Constant heat absorption tower and Displacement; Calculation in Total luminous flux reaching the Lambert target at time 1 : ; In the formula, This represents the PD sensitivity coefficient. For the first Measurements of each PD Local photocurrent at any given moment; Calculation in Concentration efficiency at any time : In the formula, This refers to the output power of the laser. Calculate the average concentration efficiency : ; Calculate the total average concentration loss : ; By setting a threshold and combining it with the physical boundary of the PD array to determine the spot overflow state, the spot area cutoff efficiency is directly calculated. The calculation process is as follows: the initial quadrilateral projection of the heliostat model on the composite target surface along the reflected light direction is set as... Its total area is The centroid of the projection is located at the PSD, based on the trajectory of the light spot ( Obtain the quadrilateral projection of the heliostat model onto the target surface. The change in the projection and the overlapping area of ​​the composite target surface represent the effective receiving area of ​​the heat absorption tower elastic model. Spot area cutoff efficiency Then it is: ; By correlating the light spot offset trajectory with the vibration displacement of the heliostat mirror surface, the losses caused by the mirror's own deformation and jitter are quantified; the contribution of heliostat vibration... : Normal displacement of the heliostat mirror surface and Coherence function calculations are performed, and integration is performed over all frequency bands with coherence functions higher than 0.8 to obtain the result. Resulting response components Heliostat vibration contribution Then it is: ; In the formula, and They are respectively variance Total variance; The beam offset trajectory is correlated with the vibration displacement of the target surface at the top of the heat absorber tower to quantify the additional losses caused by the "moving target" effect due to tower vibration; the specific process is as follows: calculate the lateral vibration displacement of the heat absorber tower. and Find the time delay with the strongest correlation using the cross-correlation function. ;Analyze whether the movement of the tower body in a specific phase systematically leads to The reduction is achieved by calculating all factors that lead to the conditional averaging method. The average efficiency over the corresponding period when the systemic decline occurs Average efficiency during the period when the tower top displacement is in a favorable phase The loss of focusing efficiency due to the different phases of tower movement That is: ; By comparing and analyzing the differences in vibration response and focusing loss of the target mirror under conditions with and without upstream interference mirrors, the contribution of pure swarm interference is decoupled. The specific calculation process is as follows: for the same moment and the same wind speed, two sets of data are processed separately for "with interference" and "without interference" to determine the average efficiency loss increment caused by swarm interference. That is: ; In the formula, and Average focusing efficiency under no interference and with interference, respectively.

[0010] The present invention also provides a heliostat wind-induced concentration loss testing device, including a solar simulation subsystem, a mirror field and heat absorption tower simulation subsystem, a synchronous measurement and data acquisition subsystem, and an integrated control system and software; The solar simulation subsystem includes a programmable single-axis mechanical pendulum structure, a sliding carriage mounted on the pendulum mechanism, a highly stable laser emitter mounted on the sliding carriage, a drive motor, and a controller; the solar simulation subsystem receives solar position commands from the main control computer to achieve dynamic and high-precision simulation of the incident beam direction; The mirror field and heat-absorbing tower simulation subsystem includes a heliostat model group and a heat-absorbing tower elastic model; the heliostat model group includes a target heliostat elastic model with a two-axis attitude adjustment mechanism and several upstream interference mirror models; the dynamic similarity ratio of the heat-absorbing tower elastic model is matched with that of the heliostat model, and a composite optical target surface unit is integrated on the top of the heat-absorbing tower elastic model; The synchronous measurement and data acquisition subsystem includes a structural response measurement unit, an optical response measurement unit, and a data synchronization acquisition instrument. The structural response measurement unit includes two sets of laser displacement gauges, which are respectively aligned with the characteristic points on the surface of the heliostat elastic model and the top characteristic point of the heat absorber elastic model to synchronously measure their vibration displacement. The optical response measurement unit includes a PSD and a PD array, which are synchronously triggered to acquire electrical signals of center position offset, energy flux density distribution, and total flux. The data synchronization acquisition instrument realizes time synchronization of wind pressure, structural vibration, and optical signals. The integrated control system and software include a built-in solar position simulation module, a heliostat attitude calculation module, a data acquisition and control module, and a concentrating loss decoupling analysis module, which automatically execute the complete process from setting operating conditions, driving equipment, synchronously acquiring data to analyzing results.

[0011] Preferably, the composite optical target unit includes a Lambertian diffuse screen, a PSD, and a PD array. The Lambertian diffuse screen is used for spot morphology imaging, the PSD is used for high-speed measurement of the spot center position, and the PD array is used for local energy flux density measurement. Specifically, the positional relationship is as follows: the Lambertian diffuse screen serves as a background plate to assist optical alignment and visualization; the PSD is placed at the center of the theoretical plane of the target surface to measure the two-dimensional coordinates of the spot centroid in real time at high frequency. The PD array is placed on an array plate of the same size as the target surface, with 24 independent silicon photodiodes arranged in three concentric rings around the PSD, and an additional independent silicon photodiode at each of the four corners; each PD is connected to an independent transimpedance amplifier for measuring local photocurrent. The sum of the photocurrents of the PD array is... .

[0012] Preferably, the upstream interference mirror model is a simplified rigid model, and the target heliostat elastic model has the same dynamic characteristics as the actual heliostat structure.

[0013] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for testing wind-induced concentration loss of a heliostat.

[0014] The present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a method for testing wind-induced concentration loss of a heliostat.

[0015] Therefore, the present invention employs the above-mentioned heliostat wind-induced concentration loss testing device and method, which has the following beneficial effects: 1) Full-condition simulation: Upgrades wind tunnel testing from static "structural testing" to dynamic "system performance testing", closely coupling all elements of time (sun position), space (mirror field layout), operation (heliostat attitude), environment (wind field and group interference) and response (tower mirror coupled vibration) in the laboratory environment, improving the authenticity of test results and engineering guidance value.

[0016] 2) Decoupling of Loss Mechanisms: Through careful experimental design and simultaneous measurement, it is possible to quantitatively distinguish and analyze the various sources of wind-induced concentrating losses: losses from the mirror's own vibration, additional losses from the "moving target" caused by the vibration of the heat absorption tower, and the aggravating effect of interference from the mirror field group. This provides a clear basis for targeted optimization design (such as improving the mirror structure, enhancing tower damping, and optimizing the mirror field layout).

[0017] 3) Direct Engineering Applications: The “operational attitude-wind-induced loss” relationship derived by this method can be directly used to correct the heliostat tracking control algorithm and introduce compensation strategies in advance when strong winds are predicted; the decoupled loss components can provide key data support for the economic assessment and operation and maintenance strategy formulation of power plants, which is of great significance for improving the overall efficiency and reliability of solar thermal power plants.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the heliostat wind-induced concentration loss testing system device according to an embodiment of the present invention; Figure 2 This is a flowchart of the heliostat wind-induced concentration loss testing method according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the solar motion pattern according to an embodiment of the present invention; Figure 4This is a schematic diagram of the sun's position according to an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the principle of establishing a dynamic optical path between a heliostat and an absorber tower according to an embodiment of the present invention. Figure 6 This is a schematic diagram of the composite optical target unit according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the heliostat's attitude according to an embodiment of the present invention; Figure 8 This is a block diagram of the integrated control system and software operation core modules of an embodiment of the present invention; Figure 9 This is a schematic diagram of the cross-sectional area of ​​the light spot according to an embodiment of the present invention. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] Example 1 This embodiment was implemented in a large boundary layer wind tunnel, using a commercial tower-type solar thermal power plant as a prototype. Based on the similarity criteria of aeroelastic models, a dynamic scaled-down model of the heliostat and the receiver tower was designed. The detailed structure and setup of the test equipment are as follows: Figure 1 As shown, the test method implementation steps are as follows: Figure 2 As shown.

[0023] The testing system includes a solar simulation subsystem, a mirror field and absorber tower simulation subsystem, a synchronous measurement and data acquisition subsystem, and an integrated control system and software.

[0024] 1) Solar Simulation Subsystem The sun's orbital patterns are as follows Figure 3As shown, the sun rises in the east and sets in the west on the horizon, with different positions corresponding to different months, dates, and times throughout the year. Based on the sun's orbital patterns, a solar simulation subsystem was established using a semi-circular track system installed in the wind tunnel test section. The solar simulation subsystem includes a programmable single-axis mechanical pendulum structure, a sliding trolley mounted on the pendulum mechanism, a highly stable laser emitter mounted on the sliding trolley, a drive motor, and a controller. The programmable single-axis mechanical pendulum structure includes a semi-circular pendulum with a track, a support, and a servo motor driving the pendulum's rotation angle. First, the semi-circular pendulum is hinged to the bottom of the wind tunnel test section by the support. The drive servo motor connected to the support allows the pendulum to rotate around the support axis, simulating the sun's altitude at different months and dates throughout the year. Second, the sliding trolley can move along the semi-circle on the track, with the laser emitter mounted on the trolley pointing towards the center of the pendulum, simulating the sun's position at different times of day.

[0025] The control core of the solar simulation subsystem is a solar position simulation module. After inputting latitude, longitude, date, and time, the solar position simulation module outputs the solar altitude angle in real time. and azimuth Instructions, such as the altitude and azimuth of the sun's position. Figure 4 As shown, the calculation formula is as follows: ; ; In the formula, Local time angle; Geographic latitude; This is the solar declination angle. Hour angle. From true solar time Sure: .

[0026] The solar simulation subsystem operates as follows: The main control software calculates the solar azimuth angle based on the target's geographical location and the test time, driving the sliding trolley to the corresponding position on the pendulum; simultaneously, it calculates the solar altitude angle, driving the pendulum to rotate to the corresponding pitch angle. Thus, the laser beam accurately simulates the incident direction of sunlight at that moment in space (e.g., ...). Figure 5 (As shown).

[0027] 2) Mirror field and heat absorption tower simulation subsystem The mirror field and receiver tower simulation subsystem includes a group of heliostat models and an elastic model of the receiver tower. The elastic model of the receiver tower is made of a lightweight aluminum alloy core column and an EVA shell. Through internal counterweight and structural stiffness adjustment, its dynamic similarity ratio is matched with that of the heliostat model. The top of the elastic model of the receiver tower integrates a composite optical target unit.

[0028] The composite optical target unit consists of a Lambertian diffused screen, a PSD, and a PD array (as shown in the attached image). Figure 6As shown). The Lambertian diffuse screen serves as a background to assist optical alignment and visualization; the PSD is placed at the center of the theoretical plane of the target surface to measure the two-dimensional coordinates of the spot's centroid in real time at high frequency. The PD array is placed on an array plate of the same size as the target surface. Twenty-four independent silicon photodiodes are arranged in three concentric rings around the PSD, with an additional independent silicon photodiode at each of the four corners. Each PD is connected to an independent transimpedance amplifier for measuring local photocurrent. (Absorption of photons to generate electrons to form photocurrent) and the sum of photocurrents from the PD array. .

[0029] The heliostat model group includes a target heliostat elastic model with a two-axis attitude adjustment mechanism and several upstream interference mirror models. The upstream interference mirror models are simplified rigid models, while the target heliostat elastic model has the same dynamic characteristics as the actual heliostat structure. Based on the actual power plant mirror field layout diagram, the coordinates of the target heliostat and interference heliostats within the field are precisely arranged in the wind tunnel test section.

[0030] 3) Synchronous Measurement and Data Acquisition Subsystem The synchronous measurement and data acquisition subsystem includes a structural response measurement unit, an optical response measurement unit, and a data synchronization acquisition instrument. The structural response measurement unit includes two sets of laser displacement gauges, which are aligned with the characteristic points on the surface of the heliostat elastic model and the top characteristic point of the endothermic tower elastic model, respectively, to synchronously measure their vibration displacement. The optical response measurement unit includes a PSD and a PD array, which are synchronously triggered to acquire electrical signals of center position offset, energy flux density distribution, and total flux. The data synchronization acquisition instrument achieves time synchronization of wind pressure, structural vibration, and optical signals.

[0031] 4) Integrated control system and software Integrated control systems and software, such as Figure 8 As shown, it incorporates a solar position simulation module, a heliostat attitude calculation module, a data acquisition and control module, and a concentrating loss decoupling analysis module, automatically executing the complete process from operating condition settings, equipment driving, data synchronization acquisition to result analysis. The functions of each module are as follows: Solar position simulation module M1: Calculates the solar altitude angle and azimuth angle, and generates control commands for the sliding trolley and the pendulum.

[0032] Heliostat attitude calculation module M2: Based on the real-time solar vector (from M1) and the fixed "mirror-tower" vector (from initial calibration), it calculates the azimuth and elevation angles required for the target heliostat in real time.

[0033] Data acquisition and control module M3: Configures acquisition parameters, sends synchronization trigger signals, and receives, displays, and stores all measurement data streams in real time.

[0034] Concentration loss decoupling analysis module M4: Built-in post-processing algorithm used to perform various decoupling analyses.

[0035] Based on the above-described apparatus, this embodiment further provides a method for testing wind-induced concentration loss of a heliostat, comprising the following steps: Before the formal experiment, the wind field was first calibrated to ensure that the wind speed and turbulence profiles were consistent with the target wind field. Secondly, the dynamic characteristics of the laser displacement meter, the heat absorber model, and the heliostat model were calibrated. Finally, the optical system was calibrated. Under windless and static conditions with indoor lighting off, the positions of the laser, heliostat model, and heat absorber model were finely adjusted to ensure that the reflected light spot accurately landed at the center of the PSD on the composite target surface and uniformly covered the central region of the PD array. The PSD signal and the baseline readings (dark current) of each PD were recorded at this time, and calibration was performed under different known light intensities to obtain the sensitivity coefficient of each PD. .

[0036] S1. Solar Position Simulation and Initial Optical Path Calibration: Based on the preset geographical location of the power station, the test date and time, the solar position simulation module obtains the solar altitude angle and azimuth angle, driving the solar simulation subsystem to adjust the beam incident angle to simulate the direction of sunlight at that moment. In this embodiment, Input test parameters: [Geographic coordinates: 37.5°N, 105°E], [Date: June 21], [Time: 09:00]. The solar position simulation module M1 calculates the solar altitude angle at this moment. and azimuth Generate instructions. The sliding cart moves to the corresponding position. The angle, the swing arm rotates to the corresponding The angle.

[0037] S2. Mirror Field Layout and Spatial Relationship Construction of Target Mirror-Target Surface: Based on the power plant's mirror field layout, a group of heliostat models is arranged within the wind tunnel test section, and the elastic model of the heat-absorbing tower is positioned proportionally. According to the prevailing wind direction (e.g., northerly wind) for the current test, the upstream interference mirror model is installed at its corresponding upwind position. The theoretical relative position between the target heliostat model and the top of the elastic model of the heat-absorbing tower is calculated based on the actual coordinates of the target heliostat model. The spatial coordinates of the composite optical target surface at the top of the elastic model of the heat-absorbing tower are adjusted to establish the initial "mirror-tower" optical path. Furthermore, if the test condition is "no interference," only the target heliostat model and the elastic model of the heat-absorbing tower are installed.

[0038] S3. Dynamic Calculation and Adjustment of Heliostat Attitude: Combining the simulated direction of sunlight in S1 and the "mirror-tower" optical path constructed in S2, the heliostat attitude calculation module obtains the elevation and azimuth angles required for the target heliostat model to reflect light to the center of the target surface, and adjusts the target heliostat model to this theoretical attitude; the heliostat attitude is as follows. Figure 7 As shown. This step is completed by the heliostat attitude calculation module M2. The specific content of this step is as follows: The solar simulation subsystem determines the unit vector of the incident direction of sunlight. According to the top coordinates of the heat absorption tower elastic model Coordinates of the heliostat model in the mirror field Based on the principle of light reflection, determine the unit vector of the reflection direction. Unit vector of normal direction of heliostat model The attitude of the heliostat model was calculated, and the elevation angle of the heliostat model was adjusted. and azimuth To establish a complete reflected light path, the calculation formula is as follows: ; ; ; ; in, These are the heliostat models in the mirror field. X coordinate, Y Coordinates, top height of the heat absorption tower elastic model; and These are the solar altitude angle and azimuth angle, respectively. and These are the elevation and azimuth angles of the heliostat model, respectively. and These are the unit vectors for the incident and reflected directions of sunlight, respectively.

[0039] S4. Introducing Wind Load and Group Disturbance Effects: A simulated wind field with specific wind speed, direction, and turbulence intensity is generated in a wind tunnel, causing the wake generated by the upstream heliostat model to act on the downstream target heliostat model, thus reproducing the group disturbance effect within the power plant's mirror field. In this embodiment, a typical atmospheric boundary layer wind field of a tower-type solar thermal power plant is simulated, and the average wind speed profile and turbulence intensity profile are consistent with the target wind field.

[0040] S5. The dynamic light spot under the coupled vibration of the tower-mirror is measured synchronously. The wind field is started and simultaneously applied to the heliostat model group and the elastic model of the heat-absorbing tower. After the wind field stabilizes, the vibration displacement of the key points of the target heliostat mirror surface and the top target area of ​​the elastic model of the heat-absorbing tower is synchronously collected through the structural response measurement unit (laser displacement meter). At the same time, the position, shape and energy distribution of the reflected light spot on the dynamic target surface are synchronously collected at high frequency through the focusing loss measurement device (PSD and PD array).

[0041] The specific operation in this embodiment is as follows: Start the wind tunnel, adjust to the target test wind speed, and after the flow field stabilizes, formally begin data acquisition. The data acquisition control module M3 starts working, and the system automatically sends a global synchronization trigger signal to the data acquisition instrument, simultaneously activating signal recording from the two laser displacement meters (LDV, PSD, and PD array). The LDV measures the wind vibration response of the heat-absorbing tower model and the target heliostat model. The LDV-1 is aligned with the center of the target heliostat mirror surface, measuring the horizontal vibration displacement of the mirror surface, which is then converted into the normal displacement of the mirror surface after angle conversion. The LDV-2 was aligned with the top side of the heat exchange tower model to measure the lateral vibration displacement of the tower top in the prevailing wind direction plane. High-frequency continuous data acquisition is performed for a sufficiently long period to include adequate statistical samples and low-frequency vibration periods (e.g., 180 seconds at a sampling frequency of 600 Hz). First, an interference-free mirror test is conducted, which serves as a control for studying the impact of interference. Then, an interference-affected mirror test is performed, during which the wind-induced vibration response and optical response of the target heliostat change. The structural and optical responses are acquired using a high dynamic range data acquisition system with multi-channel synchronous sampling capabilities. All channels (2 LDV signals, 2 PSD position signals, 28 PD current signals, etc.) are triggered by the same hardware clock, maintaining a uniform sampling frequency to ensure strict time synchronization of all data.

[0042] During this process, the wind field simultaneously excites the target heliostat (causing heliostat displacement). ) and the heat absorption tower (which causes the heat absorption tower to shift) The reflected light spot, under the combined effect of the dynamically shaking mirror and the moving target surface, produces a complex motion trajectory on the composite target surface. ), Energy distribution changes (each ) and total energy ( ).

[0043] S6: Comprehensive Analysis and Decoupling of Concentrating Efficiency Loss: Instantaneous concentrating efficiency is calculated based on collected dynamic beam data, and efficiency loss is obtained. Through data correlation analysis, the losses caused by beam area cutoff efficiency, mirror deformation and vibration, and tower vibration are quantified. The contribution of group interference is decoupled, and the variation law of wind-induced loss under different solar altitude angles is analyzed, and a correlation database is established. Specifically, the concentrating loss decoupling analysis module M4 automatically processes the data, including the following calculations: Calculate the light spot at time and Towards absolute instantaneous displacement , : , ; In the formula, , Measured from PSD time and Displacement; and They are respectively Constant heat absorption tower and Displacement; Calculation in Total luminous flux reaching the Lambert target at time 1 : ; In the formula, This represents the PD sensitivity coefficient. For the first Measurements of each PD Local photocurrent at any given moment; Calculation in Concentration efficiency at any time : ; In the formula, This refers to the output power of the laser. Calculate the average concentration efficiency : ; Calculate the total average concentration loss : ; For situations where wind-induced vibration causes light spot drift and overflows from the optical target surface at the top of the heat absorption tower, a threshold of 10% of the effective signal is set for the edge units of the PD array to determine truncation loss. If at any given moment, the average value of the outermost ring PD signal is lower than the threshold, and A significant decrease indicates "partial overflow"; if all PD signals are close to the dark current, it is considered "complete miss". Furthermore, to quantitatively calculate the area cutoff efficiency of the light spot reflection, such as... Figure 9 As shown, the initial quadrilateral projection of the heliostat onto the composite target surface along the direction of the reflected light is set as... Its total area is If the centroid of the projection is located at the PSD, then the trajectory of the light spot can be determined based on ( Obtain the quadrilateral projection of the heliostat onto the target surface. The change in the projection and the overlapping area of ​​the composite target surface constitute the effective receiving area of ​​the heat absorption tower. Spot area cutoff efficiency Then it is: ; Loss decoupling analysis is performed based on the correlation between the heliostat, the heat absorber, and the absolute displacement of the light spot: Heliostat vibration contribution :right and Coherence function calculations are performed, and integration is performed over all frequency bands with coherence functions higher than 0.8 to obtain the result. Resulting response components Heliostat vibration contribution Then it is: ; In the formula, and They are respectively variance Total variance.

[0044] Tower vibration contribution :calculate and Find the time delay with the strongest correlation using the cross-correlation function. Analyze whether the movement of the tower body in a specific phase systematically leads to... Decrease. Calculate all factors leading to [decrease] using the conditional averaging method. The average efficiency over the corresponding period when the systemic decline occurs Average efficiency during the period when the tower top displacement is in a favorable phase The loss of focusing efficiency due to the different phases of tower movement That is: ; Group interference increment For the same time and wind speed, two sets of data, one with interference and one without, are processed separately. The increase in average efficiency loss caused by group interference is calculated. That is: ; In the formula, and Average focusing efficiency under independent heliostats (no interference) and group heliostats (with interference), respectively.

[0045] Furthermore, the spot area cutoff efficiency of the two methods was compared. and mirror vibration loss The differences can be analyzed to determine the relative impact of group interference on spot overflow and mirror vibration.

[0046] Therefore, this invention employs the aforementioned heliostat wind-induced concentration loss testing device and method to achieve precise testing of heliostat wind-induced concentration loss. It couples all factors, including solar position, mirror field layout, equipment attitude, wind field environment, and tower-mirror coupled vibration, to reproduce real-world operating conditions. It can quantitatively decouple concentration losses from different causes, such as mirror surface vibration, the "moving target" effect of tower vibration, and mirror field group interference, clearly defining the proportion of each loss component. The test results can directly correct the heliostat tracking control algorithm, providing data support for heliostat structure optimization and mirror field layout improvement, thereby enhancing the concentration efficiency and power generation reliability of solar thermal power plants.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for testing wind-induced concentration loss of heliostats, applied to a wind tunnel testing system comprising a solar position simulation device, a concentration loss measurement device, a heliostat model group, and an absorber tower model, characterized in that, Includes the following steps: S1. Solar position simulation and initial optical path calibration: Based on the preset power station geographical location, test date and time, the solar position simulation module obtains the solar altitude angle and azimuth angle, drives the solar simulation subsystem to adjust the beam incident angle, and simulates the direction of sunlight at that moment; S2. Construction of the mirror field layout and target mirror-target surface spatial relationship: Based on the mirror field layout of the power station, a group of heliostat models are arranged in the wind tunnel test section and the elastic model of the heat-absorbing tower is positioned proportionally. The theoretical relative position between the target heliostat model and the top of the elastic model of the heat-absorbing tower is calculated according to the actual coordinates of the target heliostat model. The spatial coordinates of the composite optical target surface at the top of the elastic model of the heat-absorbing tower are adjusted to establish the initial "mirror-tower" optical path. S3. Dynamic calculation and adjustment of the heliostat's operating attitude: Combining the direction of sunlight simulated in S1 and the "mirror-tower" optical path constructed in S2, the elevation and azimuth angles required for the target heliostat model to reflect light to the center of the target surface are obtained through the heliostat attitude calculation module, and the target heliostat model is adjusted to this theoretical attitude. S4. Introducing wind load and group interference effect: A simulated wind field with specific wind speed, wind direction and turbulence intensity is generated in the wind tunnel, so that the wake generated by the upstream heliostat model acts on the downstream target heliostat model, and reproduces the group interference effect in the power station mirror field. S5. Synchronously measure the dynamic light spot under the coupled vibration of the tower-mirror, start the wind field and simultaneously act on the heliostat model group and the elastic model of the heat-absorbing tower. After the wind field stabilizes, the vibration displacement of the key points of the target heliostat mirror surface and the top target area of ​​the elastic model of the heat-absorbing tower is synchronously collected through the structural response measurement unit. At the same time, the position, shape and energy distribution of the reflected light spot on the dynamic target surface are synchronously collected at high frequency through the light concentration loss measurement device. S6: Comprehensive analysis and decoupling of focusing efficiency loss: Calculate instantaneous focusing efficiency and obtain efficiency loss based on collected dynamic spot data; quantify spot area cutoff efficiency, loss caused by mirror deformation and vibration, and additional loss caused by tower vibration through data correlation analysis; decouple the contribution of group interference; analyze the variation law of wind-induced loss under different solar altitude angles and establish a correlation database.

2. The method for testing wind-induced concentration loss of a heliostat according to claim 1, characterized in that, In S1, the solar simulation subsystem includes a laser emitter, a sliding trolley, a lever mechanism, a drive motor, and a controller; in S2, the composite optical target surface is a composite target surface of a Lambertian diffuse screen, a position-sensitive detector (PSD), and a photodetector (PD) array. In S1, the specific workflow of the solar simulation subsystem is as follows: based on the preset geographical location of the power station, the test date and time, calculate the solar azimuth angle and drive the sliding trolley to move to the corresponding position on the swing arm mechanism; at the same time, calculate the solar altitude angle and drive the swing arm mechanism to rotate to the corresponding pitch angle. The calculation formula is as follows: Solar altitude angle: ; Sun azimuth: ; in, Local time angle; Geographic latitude; Solar declination angle; hour angle From true solar time Sure: .

3. The method for testing wind-induced concentration loss of a heliostat according to claim 2, characterized in that, The specific content in S3 is: The solar simulation subsystem determines the unit vector of the incident direction of sunlight. According to the top coordinates of the heat absorption tower elastic model Coordinates of the heliostat model in the mirror field Based on the principle of light reflection, determine the unit vector of the reflection direction. Unit vector of normal direction of heliostat model The attitude of the heliostat model was calculated, and the elevation angle of the heliostat model was adjusted. and azimuth To establish a complete reflected light path, the calculation formula is as follows: ； ； ； ； in, These are the heliostat models in the mirror field. X coordinate, Y Coordinates, top height of the heat absorption tower elastic model; and These are the solar altitude angle and azimuth angle, respectively. and These are the elevation and azimuth angles of the heliostat model, respectively. and These are the unit vectors for the incident and reflected directions of sunlight, respectively.

4. The method for testing wind-induced concentration loss of a heliostat according to claim 3, characterized in that, In S5, the structural response measurement unit is a laser displacement meter; the focusing loss measurement device is a PSD and PD array.

5. The method for testing wind-induced concentration loss of a heliostat according to claim 4, characterized in that, In S6, the calculation methods for each loss are as follows: The instantaneous focusing efficiency is the ratio of the light energy reaching the effective receiving area of ​​the target surface to the total emitted light energy; the specific calculation process is as follows: Calculate the light spot at time and Towards absolute instantaneous displacement , : ， ； In the formula, , Measured from PSD time and Displacement; and They are respectively Constant heat absorption tower and Displacement; Calculation in Total luminous flux reaching the Lambert target at time 1 : ； In the formula, This represents the PD sensitivity coefficient. For the first Measurements of each PD Local photocurrent at any given moment; Calculation in Concentration efficiency at any time : In the formula, This refers to the output power of the laser. Calculate the average concentration efficiency : ; Calculate the total average concentration loss : ; By setting a threshold and combining it with the physical boundary of the PD array to determine the spot overflow state, the spot area cutoff efficiency can be directly calculated. The calculation process is as follows: The initial quadrilateral projection of the heliostat model onto the composite target surface along the direction of the reflected light is set as... Its total area is The centroid of the projection is located at the PSD, based on the trajectory of the light spot ( Obtain the quadrilateral projection of the heliostat model onto the target surface. The change in the projection and the overlapping area of ​​the composite target surface represent the effective receiving area of ​​the heat absorption tower elastic model. Spot area cutoff efficiency Then it is: ; By correlating the light spot offset trajectory with the vibration displacement of the heliostat mirror surface, the losses caused by the mirror's own deformation and jitter are quantified; the contribution of heliostat vibration... : Normal displacement of the heliostat mirror surface and Coherence function calculations are performed, and integration is performed over all frequency bands with coherence functions higher than 0.8 to obtain the result. Resulting response components Heliostat vibration contribution Then it is: ； In the formula, and They are respectively variance Total variance; The beam offset trajectory is correlated with the vibration displacement of the target surface at the top of the heat absorber tower to quantify the additional losses caused by the "moving target" effect due to tower vibration; the specific process is as follows: calculate the lateral vibration displacement of the heat absorber tower. and Find the time delay with the strongest correlation using the cross-correlation function. ;Analyze whether the movement of the tower body in a specific phase systematically leads to The reduction is achieved by calculating all factors that lead to the conditional averaging method. The average efficiency over the corresponding period when the systemic decline occurs Average efficiency during the period when the tower top displacement is in a favorable phase The loss of focusing efficiency due to the different phases of tower movement That is: ; By comparing and analyzing the differences in vibration response and focusing loss of the target mirror under conditions with and without upstream interference mirrors, the contribution of pure swarm interference is decoupled. The specific calculation process is as follows: for the same moment and the same wind speed, two sets of data are processed separately for "with interference" and "without interference" to determine the average efficiency loss increment caused by swarm interference. That is: ； In the formula, and Average focusing efficiency under no interference and with interference, respectively.

6. A testing apparatus for implementing the heliostat wind-induced concentration loss testing method according to any one of claims 1-5, characterized in that, It includes a solar simulation subsystem, a mirror field and heat-absorbing tower simulation subsystem, a synchronous measurement and data acquisition subsystem, and an integrated control system and software; The solar simulation subsystem includes a programmable single-axis mechanical pendulum structure, a sliding carriage mounted on the pendulum mechanism, a highly stable laser emitter mounted on the sliding carriage, a drive motor, and a controller; the solar simulation subsystem receives solar position commands from the main control computer to achieve dynamic and high-precision simulation of the incident beam direction; The mirror field and heat-absorbing tower simulation subsystem includes a heliostat model group and a heat-absorbing tower elastic model; the heliostat model group includes a target heliostat elastic model with a two-axis attitude adjustment mechanism and several upstream interference mirror models; the dynamic similarity ratio of the heat-absorbing tower elastic model is matched with that of the heliostat model, and a composite optical target surface unit is integrated on the top of the heat-absorbing tower elastic model; The synchronous measurement and data acquisition subsystem includes a structural response measurement unit, an optical response measurement unit, and a data synchronous acquisition instrument; the structural response measurement unit includes two sets of laser displacement gauges, which are respectively aligned with the feature points on the surface of the heliostat elastic model and the top feature points of the heat absorber elastic model to synchronously measure their vibration displacement. The optical response measurement unit includes a PSD and a PD array. The PSD and PD arrays are synchronously triggered to acquire electrical signals of center position offset, energy flux density distribution, and total flux. The data synchronization acquisition instrument realizes time synchronization of wind pressure, structural vibration, and optical signals. The integrated control system and software include a built-in solar position simulation module, a heliostat attitude calculation module, a data acquisition and control module, and a concentrating loss decoupling analysis module, which automatically execute the complete process from setting operating conditions, driving equipment, synchronously acquiring data to analyzing results.

7. The testing apparatus according to claim 6, characterized in that, The composite optical target unit includes a Lambertian diffuse screen, a PSD, and a PD array. The Lambertian diffuse screen is used for spot morphology imaging, the PSD is used for high-speed measurement of the spot center position, and the PD array is used for local energy flux density measurement. Specifically, the Lambertian diffuse screen serves as a background plate to assist optical alignment and visualization; the PSD is placed at the center of the theoretical plane of the target surface to measure the two-dimensional coordinates of the spot centroid in real time at high frequency. The PD array is placed on an array plate of the same size as the target surface, with 24 independent silicon photodiodes arranged in three concentric rings around the PSD, and an additional independent silicon photodiode at each of the four corners; each PD is connected to an independent transimpedance amplifier for measuring local photocurrent. The sum of the photocurrents of the PD array is... .

8. The testing apparatus according to claim 6, characterized in that, The upstream interference mirror model is a simplified rigid model, while the target heliostat elastic model has the same dynamic characteristics as the actual heliostat structure.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for testing wind-induced light concentration loss of a heliostat as described in any one of claims 1-5.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the method for testing wind-induced light concentration loss of a heliostat as described in any one of claims 1-5.

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