A method for calculating the optimal anti-collision angle of heliostats during the cleaning process.

Abstract

The present invention discloses a method for calculating the optimal anti-collision angle of a heliostat during the cleaning process of the heliostat. The cleaning route is segmented by a number of characteristic points, and for each characteristic point, the heliostats with collision risks in the surrounding area are calculated. When the cleaning equipment is about to reach the characteristic point, the real-time angle of the heliostat with collision risk is read, and an optimal anti-collision angle is calculated using an angle search method. Under the premise that the cleaning equipment passes, the angle that the heliostat needs to adjust is minimized. By using the optimal anti-collision angle calculation method for heliostats proposed by the present invention, the adjustment time of the heliostat between the cleaning state and the sun-chasing state will be greatly reduced in a tower-type solar thermal power station, which can minimize the impact of heliostat cleaning on the sun-chasing of the heliostat, and effectively improve the cleaning efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of solar thermal power generation, and in particular to a method for calculating an optimal anti-collision angle of a heliostat during a heliostat cleaning process. Background Art

[0002] It is a consensus among countries around the world to vigorously develop renewable clean energy and gradually replace traditional fossil energy. Wind power generation and photovoltaic power generation are currently more mature forms of clean energy generation, but they are greatly affected by natural weather and their power output is unstable. As the proportion of wind power generation and photovoltaic power generation in the power grid increases year by year, energy forms with energy storage and peak-shaving capabilities are in urgent need of development. Due to the existence of energy storage systems, solar thermal power generation can achieve 24-hour continuous, stable, and dispatchable power output. It is considered to be the most potential renewable energy to replace thermal power to bear the basic load and has peak-shaving capabilities.

[0003] The main technical routes for CSP include tower, trough, butterfly, Fresnel, etc., among which tower CSP is the mainstream technical route. Tower solar thermal power generation uses a large number of heliostats to reflect sunlight to the absorber, heat the working fluid in the absorber to a higher temperature, and then use the heated working fluid to heat the feed water to generate steam, which drives the steam turbine to generate electricity. Among them, the cleanliness of the heliostat mirror affects the reflection efficiency of the heliostat and directly affects the power generation of the CSP station.

[0004] In order to improve land utilization and save land area, when designing a tower solar power station, the heliostats are generally arranged relatively densely, which does not meet the condition that the mirror cleaning vehicle can still pass safely when the heliostats are free to rotate. At present, most of the heliostat control methods during cleaning are to rotate the heliostat queue to be cleaned and its surrounding adjacent heliostat queues to a fixed cleaning posture and lock them. After the mirror cleaning vehicle completes the cleaning of the entire heliostat queue, the queue to be cleaned and the surrounding adjacent queues are unlocked. The angle between the cleaning posture and the sun-chasing posture is large, and switching between the two postures will also waste a lot of time. During the operation and power generation of the power station, such a cleaning method will cause a large number of heliostats to be in a cleaning lock state, unable to reflect sunlight to the absorber, resulting in a large loss of energy in the mirror field. Summary of the invention

[0005] In view of the defects in the prior art, an object of the present invention is to provide a method for calculating an optimal anti-collision angle of a heliostat during a heliostat cleaning process.

[0006] The present invention provides a method for calculating the optimal anti-collision angle of a heliostat during a heliostat cleaning process, comprising the following steps:

[0007] Step S1: Obtain the position coordinates of each heliostat in the heliostat field of a tower solar thermal power station, and obtain the shape and size information of the heliostat and the size information of the heliostat cleaning equipment;

[0008] Step S2: Obtain the position coordinates of the heliostat cleaning equipment in the heliostat field, and calculate the cleaning tasks and cleaning routes of the heliostat cleaning equipment;

[0009] Step S3: Set a number of feature points at intervals along the cleaning route;

[0010] Step S4: Calculate the list of heliostats around the feature point that have a collision risk with the heliostat cleaning equipment when the heliostat cleaning equipment is located at each feature point;

[0011] Step S5: When the heliostat cleaning equipment performs the cleaning task along the cleaning route, every time the heliostat cleaning equipment reaches a feature point, obtain the real-time angle of the list of heliostats with a collision risk, and according to the real-time angle of the heliostat and the relative position relationship with the heliostat cleaning equipment, use the angle search method to calculate the optimal anti-collision angle of the heliostat.

[0012] Preferably, the heliostat cleaning equipment is a mirror-striding heliostat cleaning equipment.

[0013] Preferably, the heliostat cleaning equipment is a heliostat cleaning equipment that travels between rows of mirrors.

[0014] Preferably, in step S3, the distance between two adjacent feature points is less than or equal to the distance between adjacent heliostats on the cleaning route.

[0015] Preferably, in step S4, the method of intersecting the circumscribed circles of the plane projections is used to calculate the list of heliostats with a collision risk around, including the following steps:

[0016] Step S41: Calculate the projection of the heliostat cleaning equipment on the horizontal plane when it is located at the first feature point, and calculate its circumscribed circle radius r;

[0017] Step S42: Calculate the projection of each heliostat in the heliostat field of the solar thermal power station on the horizontal plane when its horizontal angle is equal to 0 degrees, and calculate its circumscribed circle radii R1, R2... Rn;

[0018] Step S43: Calculate the distances L1, L2... Ln from the first feature point to each heliostat in the heliostat field of the solar thermal power station;

[0019] Step S44: The heliostats that satisfy Lk < r + Rk are regarded as the heliostats with a collision risk near the first feature point, where k = 1, 2... n;

[0020] Step S45: repeating the steps S41 to S44 to calculate the heliostats with collision risks near each of the feature points on the cleaning route.

[0021] Preferably, the circumscribed circle intersection method of plane projection is a coarse screening algorithm that focuses on calculation speed.

[0022] Preferably, in step S5, the angle search method is a process in which the heliostat cleaning device moves along the cleaning route, and each time it reaches a characteristic point, it includes the following steps:

[0023] Step S51: acquiring a heliostat with a collision risk near the arrival feature point, and reading a horizontal angle and an azimuth angle of the heliostat;

[0024] Step S52: Calculating the plane projection of the heliostat according to the horizontal angle and the azimuth angle;

[0025] Step S53: determining whether the plane projection of the heliostat and the plane projection of the heliostat cleaning device intersect: if the determination result is that they do not intersect, the current horizontal angle and azimuth angle of the heliostat are the optimal anti-collision angle; if the determination result is that they intersect, executing step S54;

[0026] Step S54: searching the azimuth and horizontal angle with a certain angle step length, the search direction is: increasing the azimuth, decreasing the azimuth and increasing the horizontal angle, until the plane projection of the heliostat does not intersect with the plane projection of the heliostat cleaning device, recording multiple angle differences respectively searched in multiple search directions, and the optimal avoidance path of the heliostat is the search path with the smallest angle difference;

[0027] Step S55: repeating steps S52 to S54 to calculate the optimal collision avoidance angle of each heliostat with a collision risk near the feature point.

[0028] Preferably, determining whether the heliostat plane projection and the heliostat cleaning device plane projection intersect is achieved by determining whether there are any intersecting edges between the heliostat plane projection and the heliostat cleaning device plane projection.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The method for calculating the optimal anti-collision angle of a heliostat during the heliostat cleaning process provided by the present invention is applied to a tower-type solar thermal power station. The adjustment time of the heliostat between the cleaning state and the sun-chasing state will be greatly reduced, and the influence of the heliostat cleaning on the sun-chasing of the heliostat can be minimized, and the cleaning efficiency can be effectively improved. The time when the heliostat starts to turn is determined according to the real-time angle of the heliostat and the real-time position of the cleaning vehicle, so as to avoid unnecessary cleaning locks and keep as many heliostats as possible in the sun-chasing operation state; the adjacent heliostats around the heliostat to be cleaned are not locked in a fixed posture, but an optimal anti-collision angle is calculated according to their real-time angles, so that the surrounding heliostats can be restored to the sun-chasing operation state at the fastest speed while ensuring the safe passage of the cleaning vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of the technical solution of an embodiment of the present invention;

[0032] Figure 2 A schematic diagram of feature point settings according to an embodiment of the present invention;

[0033] Figure 3 A schematic diagram of calculation of heliostats with collision risk according to an embodiment of the present invention;

[0034] Figure 4 This is a flow chart of a method for calculating an optimal collision avoidance angle according to an embodiment of the present invention;

[0035] Figure 5 Schematic diagram of an optimal anti-collision angle search method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] like Figure 1 As shown, the method for calculating the optimal anti-collision angle of a heliostat during the heliostat cleaning process provided by the present invention comprises the following steps:

[0038] Step S1: obtaining the position coordinates of each heliostat in the heliostat field of the tower-type solar thermal power station, and obtaining the shape and size information of the heliostat and the shape and size information of the heliostat cleaning equipment;

[0039] Step S2: obtaining the position coordinates of the heliostat cleaning device in the heliostat field, and calculating the cleaning task and cleaning route of the heliostat cleaning device;

[0040] Step S3: a plurality of feature points are evenly set at intervals along the cleaning route. The feature points are not real points but are virtual points set to divide the cleaning route into multiple sections.

[0041] Step S4: calculating a list of heliostats around the feature point that have a collision risk with the heliostat cleaning device when the heliostat cleaning device is located at each feature point;

[0042] Step S5: When the heliostat cleaning device performs the cleaning task along the cleaning route, each time it reaches a feature point, it obtains the real-time angle of the heliostat list with collision risk around the feature point, and calculates the optimal anti-collision angle of each heliostat using an angle search method according to the real-time angle of the heliostat and its relative position relationship with the heliostat cleaning device.

[0043] Those skilled in the art can understand that the optimal anti-collision angle is defined as: the attitude angle with the smallest angle difference from the current real-time angle of the heliostat under the condition that the cleaning vehicle passes. If the heliostat or the heliostat cleaning device is a complex polygon, it can be approximately regarded as a regular shape to simplify the calculation.

[0044] In one embodiment, the heliostat cleaning device is a mirror-surface-spanning heliostat cleaning device, that is, the heliostat cleaning device spans over the heliostat to be cleaned to clean the heliostat to be cleaned.

[0045] In one embodiment, the heliostat cleaning device is a heliostat cleaning device that travels between rows of mirrors.

[0046] The setting of feature points is as follows Figure 2 shown. Figure 2 What is shown is a relatively common tower-type CSP power station mirror field design method, namely rectangular heliostats, rectangular cleaning vehicles, and arc-shaped cleaning routes. The setting of feature points must satisfy the requirement that the distance between two adjacent feature points is less than or equal to the distance between adjacent heliostats on the cleaning route, and the route of the heliostat cleaning equipment between two adjacent feature points can be approximately considered as a straight line.

[0047] The list of heliostats with collision risk is calculated by using the circumscribed circle intersection method of plane projection. Figure 3 , those skilled in the art should know that Figure 3 Only part of the cleaning route area and some heliostats are drawn. Figure 3 For example, the method includes the following steps:

[0048] Step S41: Calculate the projection of the heliostat cleaning device on the horizontal plane when it is located at the feature point P4, and calculate the radius r of its circumscribed circle;

[0049] Step S42: Calculate the projection of each heliostat in the heliostat field of the tower-type solar thermal power plant on the horizontal plane when its horizontal angle is equal to 0 degrees, and calculate the circumradius R1, R2... Rn of its circumscribed circle;

[0050] Step S43: Calculate the distances L1, L2... Ln from the P4 feature point to each heliostat in the heliostat field of the tower-type solar thermal power plant;

[0051] For the heliostats that satisfy Lk < r + Rk, they are regarded as the heliostats with a collision risk near the P4 feature point, where k = 1, 2... n. Among Figure 3 them, the heliostats that meet this condition are H1, H2, H3, and H4;

[0052] Step S45: Repeat the above steps S41 - S44 to calculate the heliostats with a collision risk near each feature point on the cleaning route.

[0053] The circumscribed circle intersection method of plane projection is a rough screening algorithm that emphasizes calculation speed. Since tower-type solar thermal power plants are generally large in scale and their heliostat fields consist of thousands of heliostats, the purpose of the circumscribed circle intersection method of plane projection is to quickly screen out the heliostats with a collision risk during the execution of the current cleaning task from the entire heliostat field, so as to reduce the calculation amount of the subsequent optimal anti-collision angle. Through these method steps, the area concerned by the subsequent algorithm is reduced from the entire heliostat field to the group of heliostats near the cleaning route.

[0054] During the process of the heliostat cleaning equipment moving along the cleaning route, every time it reaches a feature point, the following steps are executed. Refer to Figure 4 :

[0055] Step S51: Obtain the heliostats with a collision risk near the feature point, and read the horizontal angle and azimuth angle of the heliostats;

[0056] Step S52: Calculate the plane projection of the heliostat according to the horizontal angle and azimuth angle;

[0057] Step S53: Determine whether the plane projection of the heliostat intersects with the plane projection of the heliostat cleaning equipment: If the judgment result is non-intersecting, the current horizontal angle and azimuth angle of the heliostat are the optimal anti-collision angles; if the judgment result is intersecting, execute Step S54;

[0058] Step S54: Search for the azimuth angle and horizontal angle with a certain angle step sp. The search directions are: increasing the azimuth angle, decreasing the azimuth angle, and increasing the horizontal angle, until the plane projection of the heliostat does not intersect with the plane projection of the heliostat cleaning equipment. Record the angle differences a1, a2, and a3 searched in the three search directions respectively. The optimal avoidance path for this set of heliostats is the search path with the smallest angle difference;

[0059] Figure 5 Taking a heliostat as an example, the detailed calculation method of the angle search algorithm is demonstrated in detail. Figure 5 As shown in the figure, projection 0 is a plane projection drawn according to the real-time angle of the heliostat (azimuth angle AZ0, horizontal angle AT0). In this posture, the heliostat and the cleaning equipment have a risk of collision. In order to find the optimal anti-collision angle, the computer simulates the rotation angle of the heliostat: the azimuth angle of the heliostat increases with a certain step length sp, that is, it rotates clockwise. Every time a step length sp is increased, it is judged whether it intersects at this angle posture until the judgment result is that it does not intersect. Reference Figure 3 , when the heliostat rotates clockwise to posture 1, the heliostat will neither collide with the cleaning equipment nor interfere with the forward route of the cleaning equipment. The angle of the heliostat in this posture is (AZ1, AT0); similarly, the azimuth angle of the heliostat decreases with a certain step length sp, that is, it rotates counterclockwise, and a posture 2 that meets the above requirements can also be found. The angle of the heliostat in this posture is (AZ2, AT0); the horizontal angle of the heliostat increases with a certain step length sp until the above requirements are met. The angle of the heliostat in this posture is (AZ0, AT3).

[0060] The angle differences a1, a2, and a3 of the three search directions are respectively a1 = AZ1-AZ0; a2 = AZ0-AZ2; and a3 = AT3-AT0. By comparing the three, the optimal avoidance path of the heliostat is the search path with the smallest angle difference.

[0061] Step S55: repeating steps S52-S54 to calculate the optimal collision avoidance angle for each heliostat with a collision risk near the feature point.

[0062] In the embodiments applicable to the present invention, there is no situation where the plane projection of the cleaning device and the plane projection of the heliostat include each other, so to determine whether the two projections intersect, it is only necessary to determine whether each edge of the two projections intersects with each other.

[0063] It should be noted that when calculating the projection of the cleaning equipment, a certain distance margin should be left in the forward direction of the cleaning equipment to ensure that the calculated optimal anti-collision angle of the heliostat will not interfere with the forward route of the cleaning equipment.

[0064] When the heliostat cleaning device is moving forward, the optimal anti-collision angle of the heliostat around several feature points can be simulated and calculated in advance, and the time required for turning can be estimated to issue a turning command to the heliostat in advance to ensure that the heliostat has completed the turning when the cleaning device arrives, thereby reducing the waiting time of the cleaning device and improving the cleaning efficiency.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the optimal anti-collision angle of a heliostat during a heliostat cleaning process, characterized in that: The following steps are involved: Step S1: obtaining the position coordinates of each heliostat in the heliostat field of a tower-type solar thermal power station, and obtaining the shape and size information of the heliostat and the size information of a heliostat cleaning device; Step S2: acquiring the position coordinates of the heliostat cleaning device in the heliostat field, and calculating the cleaning task and cleaning route of the heliostat cleaning device; Step S3: setting a number of characteristic points at intervals along the cleaning route; Step S4: calculating a list of heliostats around the feature point that have a collision risk with the heliostat cleaning device when the heliostat cleaning device is located at each feature point; Step S5: when the heliostat cleaning device performs the cleaning task along the cleaning route, the heliostat cleaning device obtains the real-time angle of the heliostat list with collision risk each time it reaches one of the feature points, and calculates the optimal collision avoidance angle of the heliostat by using an angle search method according to the real-time angle of the heliostat and the relative position relationship with the heliostat cleaning device; The angle search method is a process in which the heliostat cleaning device moves along the cleaning route, and each time it reaches a characteristic point, it includes the following steps: Step S51: acquiring a heliostat with a collision risk near the arrival feature point, and reading a horizontal angle and an azimuth angle of the heliostat; Step S52: Calculating the plane projection of the heliostat according to the horizontal angle and the azimuth angle; Step S53: determining whether the plane projection of the heliostat and the plane projection of the heliostat cleaning device intersect: if the determination result is that they do not intersect, the current horizontal angle and azimuth angle of the heliostat are the optimal anti-collision angle; if the determination result is that they intersect, executing step S54; Step S54: searching the azimuth and horizontal angle with a certain angle step length, the search direction is: increasing the azimuth, decreasing the azimuth and increasing the horizontal angle, until the plane projection of the heliostat does not intersect with the plane projection of the heliostat cleaning device, recording multiple angle differences respectively searched in multiple search directions, and the optimal avoidance path of the heliostat is the search path with the smallest angle difference; Step S55: repeating steps S52 to S54 to calculate the optimal collision avoidance angle of each heliostat with a collision risk near the feature point.

2. The method for calculating the optimal anti-collision angle of a heliostat during the heliostat cleaning process according to claim 1, characterized in that: The heliostat cleaning device is a mirror-surface-spanning heliostat cleaning device.

3. The method for calculating the optimal anti-collision angle of a heliostat during the heliostat cleaning process according to claim 1, characterized in that: The heliostat cleaning device is a heliostat cleaning device that passes between mirror rows.

4. The method for calculating the optimal anti-collision angle of a heliostat during the heliostat cleaning process according to claim 1, characterized in that: In the step S3, the distance between two adjacent characteristic points is less than or equal to the distance between adjacent heliostats on the cleaning route.

5. The method for calculating the optimal anti-collision angle of a heliostat during the heliostat cleaning process according to claim 1, characterized in that: In step S4, the calculation of the list of heliostats with collision risks in the surrounding area adopts the circumscribed circle intersection method of plane projection, including the following steps: Step S41: calculating the projection of the heliostat cleaning device on the horizontal plane when it is located at the feature point, and calculating the radius r of its circumscribed circle; Step S42: Calculate the projection of each heliostat in the heliostat field of the CSP power station on the horizontal plane when its horizontal angle is equal to 0 degrees, and calculate the radii R1, R2, ..., Rn of its circumscribed circles; Step S43: Calculate the distance L1, L2, ..., Ln from the feature point to each heliostat in the heliostat field of the CSP power station; Step S44: The heliostats that satisfy Lk < r + Rk are regarded as the heliostats with a risk of collision near the feature point, where k = 1, 2... n; Step S45: Repeat the above steps S41 - S44 to calculate the heliostats with a risk of collision near each feature point on the cleaning route.

6. The method for calculating the optimal anti-collision angle of a heliostat during the heliostat cleaning process according to claim 5, characterized in that: The circumcircle intersection method of the planar projection is a rough screening algorithm that emphasizes calculation speed.

7. The method for calculating the optimal anti-collision angle of a heliostat during the heliostat cleaning process according to claim 1, characterized in that: Judging whether the planar projection of the heliostat intersects with the planar projection of the heliostat cleaning device is realized by judging whether there are edges that intersect pairwise between the planar projection of the heliostat and the planar projection of the heliostat cleaning device.

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