Method for Measuring Wind Speed Based on Rotational Speed Difference

Abstract

The present invention discloses a method for measuring wind speed based on rotational speed difference, belonging to the technical field of wind speed measurement. An external wind force is used to make the rotational speed of the wind measurement wheel reach above an initial rotational speed, and then the external wind force is removed, so that the wind measurement wheel continues to rotate under the action of inertia. The front of the wind measurement wheel faces the wind direction, and while recording the rotational speed of the wind measurement wheel, timing is started. When the rotational speed change of the wind measurement wheel reaches M, the timing is stopped, and the time used when the rotational speed change value is set to M is set as T. In different environments to be measured, steps one and two are repeated. When the rotational speed change amount of the wind measurement wheel is M, the corresponding T values are recorded, and different T values correspond to different wind speed values. By calibrating the corresponding relationship between the duration T and the wind speed, the actual wind speed value in the environment to be measured can be obtained. The present invention can quickly and accurately detect the wind speed, and is particularly effective for low wind speed detection.

Description

Technical Field

[0001] The invention relates to the field of wind speed measurement, and in particular to a method for measuring wind speed based on rotation speed difference. Background Art

[0002] Wind speed measurement mainly refers to the process of obtaining air flow rate through various instruments or technical means. There are many methods for measuring wind speed at present, mainly including mechanical and electronic methods. Mechanical anemometers such as cup anemometers and propeller anemometers work by measuring wind speed through the rotation speed of an object under the action of wind. Electronic anemometers include hot wire anemometers and ultrasonic anemometers. Their working principle is based on certain physical effects, such as heat exchange and changes in the propagation speed of sound waves, to convert wind speed information into electrical signals.

[0003] For traditional mechanical wind speed detection, the direct object of detection is a certain rotation speed, which often changes frequently in a wind field and is relatively unstable, which can easily lead to accidental errors, especially in low wind speed situations. Since the rotation speed is extremely low, any slight influence caused by any external factors will eventually cause the rotation speed to deviate greatly, making the measured rotation speed inaccurate.

[0004] Electronic wind speed measuring instruments are relatively complex and require high professional skills for equipment maintenance. They also have high requirements for environmental conditions in the application scenarios, such as temperature, humidity, rain and snow, etc., especially for outdoor use, which have great limitations and poor adaptability. In addition, electronic wind speed detection methods and equipment also have the above-mentioned problem of inaccurate detection at low wind speeds. Summary of the invention

[0005] The present invention is aimed at the defects of the prior art mentioned in the above background technology, and proposes a method for measuring wind speed based on rotation speed difference to solve the problem in the background technology that the adaptability and accuracy of wind speed detection, especially low wind speed detection, need to be improved urgently.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions:

[0007] The present invention provides a method for measuring wind speed based on rotational speed difference, which is performed in the following steps: using external wind force to make the rotational speed of a wind measuring wheel reach above an initial rotational speed, then removing the external wind force to make the wind measuring wheel continue to rotate under the action of inertia; placing the front of the wind measuring wheel facing the wind direction, recording the rotational speed of the wind measuring wheel and starting timing, when the rotational speed change of the wind measuring wheel reaches M, stopping timing, setting the time length used when the rotational speed change value is M as T; repeating steps one and two in different test environments, when the rotational speed change of the wind measuring wheel is M, recording the corresponding T values ​​respectively, and different T values ​​correspond to different wind speed values; calibrating the corresponding relationship between the time length T and the wind speed, that is, obtaining the actual wind speed value in the test environment.

[0008] Among them, during implementation, this additional wind force is formed by blowing a wind turbine or a compressed air source directly at the anemometer wheel. The anemometer wheel adopted can adaptively adjust its position as the wind direction changes, so that when the anemometer wheel is installed in the environment to be measured, it can automatically maintain a posture with the front facing the wind direction. Moreover, a magnetic levitation bearing can be adopted for the bearing of the anemometer wheel, and the rotation speed of the anemometer wheel is measured by a rotation speed sensor, and the rotation speed sensor can be directly opposite to a marked point on the rotating shaft of the anemometer wheel.

[0009] Specifically, when the marked point is located on the rotating shaft, the rotation speed sensor includes a light source emitter and a receiver. A disc is coaxially fixed on the rotating shaft, and there is a perforation at the edge of the disc. The light source emitter and the receiver are arranged opposite to each other at both ends of the disc. When the disc rotates synchronously with the rotating shaft, when the light source emitter, the receiver, and the perforation are collinear, the receiver receives a light signal; at the initial moment, the light source emitter, the receiver, and the perforation are collinear. During the measurement process, the number K of the light signals is characterized as the rotation speed of the anemometer wheel.

[0010] As a design detail of the present invention, a first electromagnet is further provided on one side of the rotating shaft, and a magnet is embedded on the surface of the rotating shaft. When the first electromagnet is energized, the magnet and the first electromagnet attract each other and are arranged opposite to each other. At this time, the light source emitter, the receiver, and the perforation are collinear; at the initial moment, while the first electromagnet is powered off, an additional wind force is applied to the anemometer wheel, and the receiver starts to receive the light signal.

[0011] The present invention has N perforations at the edge of the disc. All the perforations form an annular array with the center of the disc as the center of the circle, and the axial directions of all the perforations are parallel to the axial direction of the disc. The rotation speed value of the anemometer wheel is characterized as the value of K / N. In particular, the present invention is provided with a coaxial cylindrical housing outside the rotating shaft. The anemometer wheel is located at the front end of the housing and is coaxially sleeved and installed on the large end of the conical flow divider at the front end of the housing. A counterweight disc is also fixed at the end of the rotating shaft away from the anemometer wheel. The counterweight disc makes the two ends balanced after the rotating shaft is installed on the bearing; a plate-shaped tail fin is fixed at the rear end of the housing, and the tail fin is located in a vertical plane, so that after the anemometer wheel is installed, when the environmental wind blows on the tail fin, the posture of the entire housing can be adaptively adjusted, so that the anemometer wheel at the front end of the housing can be automatically adjusted to a posture with the front facing the wind direction together with the housing.

[0012] In addition, a bracket for supporting the casing is installed, and a track wheel is fixed on the bracket. A ring-shaped chute is provided on the cylindrical surface of the track wheel. The axis of the chute is vertically arranged, and a connecting rod is coaxially fixed at the bottom end of the sliding shaft. The bottom end of the connecting rod is hinged to the casing so that the casing can rotate around the bottom end of the connecting rod in the horizontal plane. A magnetic slider is fixedly connected to the casing through a suspension rod. The magnetic slider is in annular sliding fit with the chute. When the tail wing is blown by the wind in the environment to be measured and drives the entire casing and the anemometer wheel to rotate synchronously, the slider slides along the chute to maintain the stability of the posture of the casing and the anemometer wheel in the horizontal direction. When the rotation reaches the position, the second electromagnet in the track wheel is energized to attract and fix the magnetic slider to fix the front windward posture of the anemometer wheel at this time.

[0013] In the present invention, the bottom end of the connecting rod is hinged to the casing by a spherical hinge, and a spirit level is installed on the surface of the casing. The suspension rod adopts a two-section combined structure. A first spherical shell is fixed at the bottom end of the upper rod section, and a second spherical shell is fixed at the top end of the lower rod section. The two spherical shells are concentric with the spherical hinge, and the second spherical shell is slidably fitted to the inner surface of the first spherical shell. An electromagnet is respectively provided in each of the two spherical shells. When the two electromagnets are energized, the two spherical shells attract each other and are fixed as a whole. Before measuring the wind speed, first make the electromagnets in the two spherical shells energize simultaneously, and the second electromagnet is energized. Observe whether the spirit level on the outer shell is in a horizontal position to verify whether the anemometer wheel is axially horizontally installed at this time. If it is not in a horizontal position, manually adjust the position of the casing through the spherical hinge. When the spirit level is kept horizontal, the electromagnets in the two spherical shells are immediately energized, and the two spherical shells are fixedly fitted together. Finally, make the second electromagnet de-energize. At this time, the anemometer wheel will adaptively rotate around the spherical hinge in the horizontal plane along with the current wind direction until it rotates to the windward posture and remains relatively stable, and then the second electromagnet resumes power supply.

[0014] Compared with the current technologies in this field, the present invention has the following series of beneficial effects: The method for measuring wind speed based on the rotational speed difference measures the wind speed through the rotational speed difference instead of an absolute rotational speed value, which is more accurate and has smaller accidental errors. The cumulative influence of the wind flow is characterized by the time of the rotational speed difference to quickly measure the average wind speed. Moreover, especially for low wind speed occasions, it can greatly reduce the rotational resistance of the anemometer wheel and lower the threshold for measuring the wind speed, and can measure lower wind speeds. And because during the wind speed measurement process, at the beginning, not only the wind flow acts on the anemometer wheel, but also an external wind force is assisted, it can more quickly and reliably measure in a low wind speed environment. After simulating it to a relatively high rotational speed, then by setting the time used for the change amount of the rotational speed difference, the wind speed value is measured, avoiding the disadvantage that the rotational speed is small at low wind speeds and the accidental error has a greater impact on it.

[0015] Through the present invention, in an environment with a known wind speed value, the wind speed value can be characterized by measuring the time T corresponding to the set number of revolutions M when the wind measuring wheel descends, and a similar functional relationship y = aT is obtained, where y = wind speed value, a = correction coefficient, and T = time. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the core technical solution of the present invention, at least one embodiment based on the core concept of the present invention will be briefly introduced below, and if necessary, supplemented by the structural schematic diagrams required in the relevant prior art. Of course, the following drawings are only several feasible embodiments of the concept of the present invention. For those of ordinary skill in the art, without additional creative labor, some adaptable technical designs that may be represented can also be developed based on these drawings.

[0017] Figure 1 It is a schematic diagram of a specific installation method of the wind measuring wheel in the present invention;

[0018] Figure 2 It is a schematic diagram of the end face of the disc.

[0019] Description of the reference numerals: wind measuring wheel 1, rotating shaft 2, bearing 3, housing 4, first electromagnet 5, magnet 6, disc 7, receiver 8, light source emitter 9, counterweight disc 10, spherical hinge 11, tail fin 12, bracket 13, track wheel 14, chute 15, suspension rod 16, magnetic slider 17, second electromagnet 18, connecting rod 19, shunt cover 20, first spherical housing 21, second spherical housing 22, perforation 23. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to make the creative features and technical means achieved by the present invention more clearly understood, the related technical solutions of the present invention will be described in detail here. Those of ordinary skill in the art should understand that the solutions described in all the following embodiments are only some feasible or recommended implementation structures or methods of the present invention, and not all the embodiments embodied by the present invention.

[0021] This embodiment discloses in detail a method for measuring wind speed based on rotation speed difference. When measuring, in the case of known wind speed, it is necessary to first apply an external wind force to make the rotation speed of the wind wheel 1 reach an initial rotation speed or higher. Especially for low wind speed, the external wind force can cause it to rotate quickly and have an initial speed M1. Then, the external wind force is removed, so that the wind wheel 1 continues to rotate under the action of inertia, and it is best to immediately turn the wind wheel 1 to face the wind direction. In practice, it is best to set the wind wheel 1 to face the wind when the external force is applied, so that it can immediately rotate only under the windward condition after the external wind force is removed. During this period, the operator needs to record the rotation speed of the wind wheel 1 and start timing. When the rotation speed of the wind wheel 1 changes to M, for example, it decreases to the rotation speed of M2, and M1-M2 is equal to M, the timing is stopped immediately. Assuming that the time used during this period of speed change value M is T, this T value is recorded.

[0022] Then, continue to repeat steps one and two in different test environments with known wind speeds. When the speed change of the wind wheel 1 is M, record the corresponding T values. Different T values ​​must correspond to different wind speed values, so that the different wind speeds in the test environment are indirectly reflected by the different T values. Finally, the corresponding relationship between the time duration T and the wind speed can be calibrated by fitting curves and other methods. For example, the horizontal axis is the T value and the vertical axis is the wind speed value. The actual wind speed value in the test environment can be directly obtained according to the curve, that is, the time T required for the speed change of the wind wheel 1 to reach M to characterize the corresponding wind speed.

[0023] In actual measurement, the above-mentioned external wind force can be generated by an electric fan, and the electric fan or compressed air source is blown directly toward the wind measuring wheel 1, so that the wind measuring wheel 1 can quickly rotate to the initial speed M1. In addition, as one of the specific implementation details, during measurement, the wind measuring wheel 1 used can adaptively adjust its position as the wind direction changes, so that when the wind measuring wheel 1 is installed in the environment to be measured, it can deflect with the wind and automatically maintain a posture facing the wind direction, so as to accurately and stably measure the wind speed.

[0024] In order to reduce the rotational damping of the wind measuring wheel 1, in this embodiment, the bearing 3 of the wind measuring wheel 1 adopts a magnetic bearing 3, and the rotational speed of the wind measuring wheel 1 is directly measured by a rotational speed sensor. The rotational speed sensor can face a marking point on the rotating shaft 2 of the wind measuring wheel 1, and the rotational speed of the wind measuring wheel 1 is determined according to the number of times the marking point faces the rotational speed sensor.

[0025] In more detail, during the measurement process, if Figure 1As shown, when the marking point is located on the rotating shaft 2, the rotational speed sensor includes a light source emitter 9 and a receiver 8. The light source emitter 9 emits specific light, and the receiver 8 is used to receive the light. At the same time, a disc 7 is coaxially fixed on the rotating shaft 2. There is a perforation 23 at the edge of the disc 7. The light source emitter 9 and the receiver 8 are arranged opposite to each other at both ends of the disc 7. During the measurement, when the disc 7 rotates synchronously with the rotating shaft 2, the perforation 23 will intermittently pass between the light source emitter 9 and the receiver 8. That is, when the light source emitter 9, the receiver 8, and the perforation 23 are collinear, the above-mentioned receiver 8 will receive a light signal and record it, indicating that the anemometer wheel 1 has rotated one circle. Specifically, in order to make the rotational speed measurement more accurate, at the initial moment of the measurement, when the anemometer wheel 1 has not rotated yet, the light source emitter 9, the receiver 8, and the perforation 23 are in a collinear state. During the measurement process, the number K of light signals represents the rotational speed of the anemometer wheel 1. For example, within one minute, the number K of light signals received by the receiver 8 is 55, which means that the rotational speed of the anemometer wheel 1 during this period is 55 r / min.

[0026] To ensure that after each measurement, the anemometer wheel 1 is reset to the position where the light source emitter 9, the receiver 8, and the perforation 23 are collinear, as Figure 1 shown, a first electromagnet 5 is specially provided on one side of the rotating shaft 2. A magnet 6 is embedded on the surface of the rotating shaft 2. When the first electromagnet 5 is energized, the generated magnetic suction force makes the magnet 6 rotate actively and approach. Eventually, the magnet 6 and the first electromagnet 5 return to the position where they are opposite to each other because of this attraction force. This position is the position where the light source emitter 9, the receiver 8, and the perforation 23 are collinear. During the actual measurement, first, the first electromagnet 5 is de-energized so that the anemometer wheel 1 returns to the free state. At the same time, an external wind force is applied to the anemometer wheel 1, causing the anemometer wheel 1 to rotate rapidly, and the receiver 8 starts to receive light signals to record the rotational speed of the anemometer wheel 1.

[0027] To improve the accuracy of the rotational speed measurement, there is more than one perforation 23 in this embodiment. Instead, there are N perforations 23 at the edge of the disc 7. At this time, when the anemometer wheel 1 rotates one circle, N light signals are required to reflect it, and the accuracy is higher. Specifically, as Figure 2 shown, all the perforations 23 form an annular array with the center of the disc 7 as the center of the circle. The axial directions of all the perforations 23 are parallel to the axial direction of the disc 7. The rotational speed value of the anemometer wheel 1 is characterized by the value of K / N. For example, within one minute, there are 550 light signals, and there are 20 perforations 23 on the disc 7, then the rotational speed is 27.5 r / min.

[0028] As one of the better measurement methods, as Figure 1As shown in the figure, a cylindrical housing 4 coaxial with the rotating shaft 2 can be provided outside the rotating shaft 2. The surface of the housing 4 is preferably smooth. At this time, the anemometer wheel 1 is located at the front end of the housing 4 and is coaxially sleeved and installed on the large end of the conical flow divider 20 at the front end of the housing 4. The conical flow divider 20 evenly disperses the airflow on each blade of the anemometer wheel 1. In addition, due to the presence of the anemometer wheel 1, the weights at both ends of the entire rotating shaft 2 are unbalanced, which will affect the stability of its installation on the bearing 3 and increase the damping coefficient. Therefore, a counterweight disk 10 is fixed at the end of the rotating shaft 2 away from the anemometer wheel 1. After the rotating shaft 2 is installed on the bearing 3, the counterweight disk 10 keeps both ends balanced, so that the rotating shaft 2 is naturally installed in the bearing 3, reducing the contact friction with the bearing 3, especially the contact friction of the bearing 3 far from the anemometer wheel 1.

[0029] In practice, as Figure 1 shown, a plate-shaped tail fin 12 can also be fixed at the rear end of the housing 4. The tail fin 12 is located in a vertical plane and can have a relatively large area to increase the contact area with the airflow. Just after the anemometer wheel 1 is installed, when the ambient wind blows across the tail fin 12, the attitude of the entire housing 4 can be adaptively adjusted so that the anemometer wheel 1 at the front end of the housing 4 can automatically adjust its attitude together with the housing 4, making the measurement attitude face the wind head-on.

[0030] As an implementation detail, as Figure 1 shown, in this embodiment, a bracket 13 for supporting the housing 4 is also installed. The bracket 13 can be fixedly installed on the ground, and a track wheel 14 is fixed on the bracket 13. A circular chute 15 is provided on the cylindrical surface of the track wheel 14. The chute 15 can adopt a T-shaped groove or a dovetail groove structure. The axis of the chute 15 is vertically arranged, and a connecting rod 19 is coaxially fixed at the bottom end of the sliding shaft. The bottom end of the connecting rod 19 is hinged to the housing 4, so that the housing 4 can freely rotate around the bottom end of the connecting rod 19 at least in the horizontal plane.

[0031] In order to enable the anemometer wheel 1 to remain relatively stable after reaching the measurement attitude, as Figure 1As shown in the figure, a magnetic slider 17 is also fixedly connected to the housing 4 through a suspension rod 16. The magnetic slider 17 is in a circular sliding fit with the chute 15, that is, the magnetic slider 17 can slide within the chute 15. When the wind in the environment to be measured blows the tail fin 12 and drives the entire housing 4 and the anemometer wheel 1 to rotate in the horizontal plane, the slider slides along the chute 15 to maintain the stability of the attitude of the housing 4 and the anemometer wheel 1 in the horizontal direction, and avoid the anemometer wheel 1 and its housing 4 swaying up and down under the action of the wind. When the anemometer wheel 1 rotates to the appropriate position to adapt to the current wind direction, the second electromagnet 18 located within the track wheel 14 is energized to attract and fix the magnetic slider 17, and the housing 4 is kept relatively fixed. Thus, the anemometer wheel 1 is kept relatively fixed, and finally the front windward attitude of the anemometer wheel 1 at this time can be fixed to better measure the wind speed.

[0032] During detection, the ground where the anemometer wheel 1 is installed, or rather the above-mentioned bracket 13, may be uneven. Or due to other environmental reasons or the reasons of the operator for installing the anemometer wheel 1, the anemometer wheel 1 is not installed horizontally. Then it is necessary to adjust it. Specifically, as Figure 1 shown, the bottom end of the connecting rod 19 and the housing 4 can be hinged by a spherical hinge 11. A spirit level is installed on the surface of the housing 4 to visually check whether the housing 4, or rather the anemometer wheel 1, is installed in a horizontal position. More specifically, the suspension rod 16 adopts a two-section combined structure. The bottom end of the upper rod section is fixed with a first spherical housing 21, and the top end of the lower rod section is fixed with a second spherical housing 22. The two spherical housings are concentric with the spherical hinge 11, and the second spherical housing 22 is slidably fitted to the inner surface of the first spherical housing 21. With such a design, when adjusting the position of the housing 4, no matter how it is adjusted, the two spherical housings can be closely attached to each other without separation, ensuring the integrity of the suspension rod 16. In addition, an electromagnet needs to be provided in each of the two spherical housings respectively. When the two electromagnets are energized, the two spherical housings attract each other and are fixed as a whole, and the suspension rod 16 becomes a rigid rod. After the two electromagnets are powered off, the suspension rod 16 becomes two rod members that can slide relative to each other but do not separate.

[0033] Before measuring the wind speed in the current environment using this wind speed measurement method, the electromagnets in the two spherical shells should be energized simultaneously to ensure that the suspension rod 16 is a complete rigid rod. At the same time, the second electromagnet 18 is also energized to avoid the slight instability and swaying of the machine housing 4 that may affect the observation of the level. Check whether the level on the outer shell is in a horizontal position to verify whether the wind speed measuring wheel 1 is axially horizontally installed at this time. If it is not in a horizontal position, cut off the power supply of the electromagnets in the two spherical shells, and the suspension rod 16 becomes an adjustable movable rod. Then, manually adjust the position of the machine housing 4 through the spherical hinge 11. When the level is kept horizontal, the electromagnets in the two spherical shells are immediately restored to power, and the two spherical shells are fixedly attached to form a whole, and the suspension rod 16 is restored to an integral rigid structure. Finally, cut off the power supply of the second electromagnet 18 to release the magnetic slider 17. At this time, the wind speed measuring wheel 1 will adaptively rotate around the spherical hinge 11 in the horizontal plane along with the current wind direction until it rotates to the windward attitude and remains relatively stable. Then, the second electromagnet 18 is powered on again to fix the magnetic slider 17 at this time, that is, to fix the installation attitude of the machine housing 4 and the wind speed measuring wheel 1 at this time.

[0034] Finally, it should be specifically noted that in all the content recorded in the present invention, such as the terms "including", "comprising", and other general statements are all based on the non-exclusive inclusion of technologies, so that the processes, articles, methods, or related devices of the corresponding elements not only mean including these technical elements, but also simultaneously include the inherent characteristics of a certain process, article, device, and method.

[0035] As those of ordinary skill in the art should clearly know, any person familiar with the technical field of the present invention can, on the basis of fully understanding the technical principle of the present invention, make adaptive improvement designs or equivalent replacements based on the above embodiments. Therefore, several technical solutions that do not depart from the core technical concept of the present invention should actually be included within the protection scope of the present invention.

Claims

1. A method for measuring wind speed based on rotation speed difference, characterized in that: Follow the steps below, Step 1: using external wind force to make the rotation speed of the wind measuring wheel (1) reach a speed above an initial rotation speed, and then removing the external wind force to make the wind measuring wheel (1) continue to rotate under the action of inertia; Step 2: Place the wind measuring wheel (1) facing the wind direction, record the speed of the wind measuring wheel (1) and start timing. When the speed change of the wind measuring wheel (1) reaches M, stop timing, and set the time taken when the speed change value is M as T; Step 3, repeating steps 1 and 2 in different test environments, when the speed change of the wind wheel (1) is M, record the corresponding T values, and different T values ​​correspond to different wind speed values; Step 4: calibrate the corresponding relationship between the time duration T and the wind speed, that is, obtain the actual wind speed value in the test environment.

2. The method for measuring wind speed based on rotation speed difference according to claim 1, characterized in that: The external wind force is generated by blowing an electric fan or a compressed air source directly toward the wind measuring wheel (1).

3. The method for measuring wind speed based on rotation speed difference according to claim 1, characterized in that: The adopted wind measuring wheel (1) can adaptively adjust its position as the wind direction changes, so that when the wind measuring wheel (1) is installed in the environment to be measured, it can automatically maintain a posture facing the wind direction.

4. The method for measuring wind speed based on rotation speed difference according to claim 1, characterized in that: The bearing (3) of the wind measuring wheel (1) adopts a magnetic suspension bearing (3), and the rotation speed of the wind measuring wheel (1) is measured by a rotation speed sensor, and the rotation speed sensor can be directly opposite to a marking point on the rotating shaft (2) of the wind measuring wheel (1).

5. The method for measuring wind speed based on rotation speed difference according to claim 4, characterized in that: When the marking point is located on the rotating shaft (2), the rotation speed sensor comprises a light source transmitter (9) and a receiver (8); a disk (7) is coaxially fixed on the rotating shaft (2); the disk (7) has a through hole (23) at the edge; the light source transmitter (9) and the receiver (8) are arranged opposite to each other at two ends of the disk (7); when the disk (7) rotates synchronously with the rotating shaft (2), the light source transmitter (9), the receiver (8) and the through hole (23) are in a colinear line, and the receiver (8) receives a light signal; At the initial moment, the light source transmitter (9), the receiver (8) and the perforation (23) are collinear. During the measurement process, the number K of the light signals represents the rotation speed of the wind wheel (1).

6. The method for measuring wind speed based on rotation speed difference according to claim 5, characterized in that: A first electromagnet (5) is also provided on one side of the rotating shaft (2), and a magnet (6) is embedded in the surface of the rotating shaft (2). When the first electromagnet (5) is energized, the magnet (6) and the first electromagnet (5) attract each other and are arranged opposite to each other. At this time, the light source transmitter (9), the receiver (8) and the perforation (23) are collinear. At the initial moment, the first electromagnet (5) is powered off and external wind force is applied to the wind wheel (1), and the receiver (8) starts to receive the light signal.

7. The method for measuring wind speed based on rotation speed difference according to claim 5, characterized in that: The disk (7) is provided with N perforations (23) near the edge, all the perforations (23) are arranged in a circular array with the center of the disk (7) as the center of the circle, the axial directions of all the perforations (23) are parallel to the axial direction of the disk (7), and the rotation speed value of the wind measuring wheel (1) is represented by a value of K / N.

8. The method for measuring wind speed based on rotation speed difference according to claim 5, characterized in that: A cylindrical casing (4) coaxial with the rotating shaft (2) is provided outside the rotating shaft (2); the wind measuring wheel (1) is located at the front end of the casing (4) and is coaxially sleeve-mounted on the large end of a conical flow divider (20) at the front end of the casing (4); a counterweight plate (10) is also fixed to the end of the rotating shaft (2) away from the wind measuring wheel (1); the counterweight plate (10) ensures that the two ends of the rotating shaft (2) remain balanced after being installed on the bearing (3); A plate-shaped tail wing (12) is fixed to the rear end of the casing (4), and the tail wing (12) is located in a vertical plane, so that after the wind measuring wheel (1) is installed and the ambient wind blows on the tail wing (12), the posture of the entire casing (4) can be adaptively adjusted, so that the wind measuring wheel (1) at the front end of the casing (4) is automatically adjusted to a posture facing the wind direction together with the casing (4).

9. The method for measuring wind speed based on rotation speed difference according to claim 8, characterized in that: A bracket (13) for supporting the housing (4) is also installed, a track wheel (14) is fixed on the bracket (13), a circle of annular slide grooves (15) are provided on the cylindrical surface of the track wheel (14), the axis of the slide groove (15) is vertically arranged, and a connecting rod (19) is coaxially fixed at the bottom end of the slide shaft, the bottom end of the connecting rod (19) is hinged to the housing (4) so ​​that the housing (4) can rotate around the bottom end of the connecting rod (19) in a horizontal plane; The housing (4) is also fixedly connected to a magnetic slider (17) via a hanging rod (16), and the magnetic slider (17) and the slide groove (15) are in annular sliding cooperation. When the environmental wind to be measured blows the tail wing (12) and causes the entire housing (4) and the wind measuring wheel (1) to rotate synchronously, the slider slides along the slide groove (15) to maintain the stability of the housing (4) and the wind measuring wheel (1) in the horizontal direction; when the rotation is in place, the second electromagnet (18) located in the track wheel (14) is energized to attract and fix the magnetic slider (17) to fix the front windward posture of the wind measuring wheel (1) at this time.

10. The method for measuring wind speed based on rotation speed difference according to claim 9, characterized in that: The bottom end of the connecting rod (19) is hinged to the housing (4) by a spherical hinge (11), and a level is installed on the surface of the housing (4); The suspension rod (16) adopts a two-section combined structure, wherein a first ball shell (21) is fixed to the bottom end of the upper rod section, and a second ball shell (22) is fixed to the top end of the lower rod section, the two ball shells are arranged concentrically with the spherical hinge (11), and the second ball shell (22) is slidably fitted on the inner surface of the first ball shell (21); an electromagnet is respectively arranged in the two ball shells, and when the two electromagnets are energized, the two ball shells attract each other and are fixed as one. Before measuring the wind speed, the electromagnets in the two spherical shells are energized at the same time, and the second electromagnet (18) is also energized. It is observed whether the spirit level on the outer shell is in a horizontal position to verify whether the wind wheel (1) is installed axially horizontally at this time. If it is not in a horizontal position, the electromagnets in the two spherical shells are de-energized at the same time, and the position of the housing (4) is manually adjusted through the spherical hinge (11). When the spirit level is kept horizontal, the electromagnets in the two spherical shells are energized again, and the two spherical shells are fixed and fitted together. Finally, the second electromagnet (18) is de-energized. At this time, the wind wheel (1) will adaptively rotate around the spherical hinge (11) in the horizontal plane according to the current wind direction until it rotates to a windward posture and remains relatively stable. Then, the second electromagnet (18) is powered on again.

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