An Offshore Wind Monitoring Method and System

Abstract

A method and system for offshore wind power monitoring, which relate to the technical field of wind power equipment. The deformation amount of the blade is measured by a blade deformation measuring device, the rotational speed of the impeller is measured by an impeller rotational speed measuring device, the wind direction is measured by a wind direction measuring device, and the analysis module analyzes the deformation amount of the blade, the rotational speed of the impeller and the wind direction. Furthermore, the first wind force value is determined through the deformation amount of the blade, the second wind force value is determined through the rotational speed of the impeller, and by comparing the first wind force value and the second wind force value, the accuracy of the currently measured wind force value is determined. If the difference between the first wind force value and the second wind force value is less than a preset value, it is determined that the current wind force value is accurate enough.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power equipment, and in particular, to a method and system for monitoring offshore wind power. Background Art

[0002] Offshore wind power generation is a new power generation method that utilizes offshore wind resources. In the face of the increasingly severe situation of oil resources, all countries have turned their attention to the sea areas with huge wind resources.

[0003] The principle of wind power generation is to use the wind to drive the rotation of the windmill blades, and then increase the rotation speed through a speed increaser to promote the generator to generate electricity. Since wind power generation does not involve fuel problems and does not produce radiation or air pollution, it is a clean and environmentally friendly power generation method.

[0004] When using a wind turbine for power generation, in order to enable the wind turbine to adjust itself in time so that it can achieve the maximum power generation efficiency or make timely adjustments to special situations, it is necessary to monitor the offshore wind power in real time. The conventional monitoring method is to calculate the wind force value based on the power generation efficiency of the wind turbine. If the wind turbine is worn or malfunctioning, the measured wind force is not accurate. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for monitoring wind power with more accurate measurement.

[0006] Therefore, the present invention discloses a method for monitoring offshore wind power, which is applied with a blade deformation measurement device, an impeller rotation speed measurement device, and a wind direction measurement device. The blade deformation measurement device is used to measure the deformation amount of the blade, the impeller rotation speed measurement device is used to measure the impeller rotation speed, and the wind direction measurement device is used to measure the wind direction;

[0007] The method includes:

[0008] Preset a blade deformation-wind force comparison table and an impeller rotation speed-wind force comparison table. The blade deformation-wind force comparison table is used to judge the comparison relationship between blade deformation and wind force, and the impeller rotation speed-wind force comparison table is used to judge the comparison relationship between impeller rotation speed and wind force;

[0009] Obtain the wind direction, and drive the yaw motor of the wind turbine to rotate according to the wind direction so that the impeller shaft is parallel to the wind direction;

[0010] If the impeller shaft is parallel to the wind direction, obtain the blade deformation amount, and determine the first wind force value according to the blade deformation-wind force comparison table;

[0011] If the impeller shaft is parallel to the wind direction, obtain the impeller rotation speed, and determine the second wind force value according to the impeller rotation speed-wind force comparison table;

[0012] If the difference between the first wind force value and the second wind force value is less than or equal to a preset value, the average value of the first wind force value and the second wind force value is determined as the current wind force value.

[0013] In some embodiments of the present application, in order to be able to determine the wind force value according to the blade deformation amount comparison table, the content of the blade deformation amount comparison table is disclosed. The content of the blade deformation wind force comparison table includes several wind force value intervals connected end to end and several blade deformation amount intervals connected end to end, and each wind force value interval corresponds to a deformation amount interval one by one.

[0014] In some embodiments of the present application, in order to be able to determine the first wind force value, a method of applying the blade deformation amount comparison table is disclosed. The method of applying the blade deformation comparison table includes:

[0015] Obtain the blade deformation amount, judge the blade deformation amount interval to which it belongs, judge the wind force value interval corresponding to the blade deformation amount interval, and take the intermediate value of the determined wind force interval as the first wind force value.

[0016] In some embodiments of the present application, in order to be able to determine the wind force value according to the impeller rotation speed, the content of the impeller rotation speed comparison table is disclosed. The content of the impeller rotation speed wind force comparison table includes several impeller rotation speed intervals connected end to end and several wind force value intervals connected end to end, and each impeller rotation speed interval corresponds to a wind force value interval one by one.

[0017] In some embodiments of the present application, in order to be able to determine the second wind force value, a method of applying the rotation speed wind force comparison table is disclosed. The method of applying the rotation speed wind force comparison table includes:

[0018] Obtain the impeller rotation speed, judge the impeller rotation speed interval to which the current impeller rotation speed belongs, judge the wind force value interval corresponding to the impeller rotation speed interval, and take the intermediate value of the determined wind force value interval as the second wind force value.

[0019] In some embodiments of the present application, in order to be able to measure the wind direction more accurately, the wind direction measuring device is improved. The wind direction measuring device includes a first wind vane and a second wind vane. The first wind vane is connected with a first angle measuring device for measuring a first wind direction value, and the second wind vane is connected with a second angle measuring device for measuring a second wind direction value;

[0020] If the difference between the first wind direction value and the second wind direction value is less than a preset value, the average value between the first wind direction value and the second wind direction value is determined as the current wind direction value.

[0021] In some embodiments of the present application, in order to accurately measure the wind power even when there are abnormalities or wear in the generator set, the offshore wind power monitoring method is improved. The method further includes:

[0022] If the difference C between the first wind power value A and the second wind power value B is greater than a preset value, then re-determine the current wind power value H. The current wind power value H is re-determined as H = k1*A + k2*B, where k1 is the first wind power value coefficient and k2 is the second wind power value coefficient.

[0023] In some embodiments of the present application, the method for determining the first wind power value coefficient k1 and the second wind power value coefficient k2 includes:

[0024] There is a difference record table set for the difference C between the first wind power value A and the second wind power value B. For each difference C in the difference record table, there is a corresponding k1 value and k2 value associated with it;

[0025] Obtain the difference C, and determine the k1 value and k2 value according to the difference record table.

[0026] An offshore wind power monitoring method disclosed in the present application determines the first wind power value by analyzing and judging the deformation amount of the blade, determines the second wind power value by analyzing and judging the impeller rotation speed, and determines the accuracy of the currently measured wind power value by comparing the first wind power value and the second wind power value. If the difference between the first wind power value and the second wind power value is less than the preset value, it is determined that the current wind power value is accurate enough.

[0027] In some embodiments of the present application, there is also disclosed an offshore wind power monitoring system. The system includes:

[0028] A blade deformation measurement device for measuring the deformation amount of the blade;

[0029] An impeller rotation speed measurement device for measuring the impeller rotation speed;

[0030] A wind direction measurement device for measuring the wind direction;

[0031] An analysis module for analyzing the deformation amount of the blade, the impeller rotation speed and the wind direction, and having a blade deformation - wind power comparison table and an impeller rotation speed - wind power comparison table built - in;

[0032] The analysis module drives the yaw motor of the wind turbine to rotate according to the wind direction, so that the impeller shaft is parallel to the wind direction. If the impeller shaft is parallel to the wind direction, the deformation amount of the blade is obtained, and according to the blade deformation-wind force comparison table, the first wind force value is determined. The impeller rotation speed is obtained, and according to the impeller rotation speed-wind force comparison table, the second wind force value is determined. If the difference between the first wind force value and the second wind force value is less than or equal to the preset value, the average value of the first wind force value and the second wind force value is determined as the current wind force value.

[0033] An offshore wind power monitoring system disclosed in this application measures the deformation amount of the blade through a blade deformation measuring device, measures the impeller rotation speed through an impeller rotation speed measuring device, measures the wind direction through a wind direction measuring device, and analyzes the deformation amount of the above-mentioned blade, the impeller rotation speed and the wind direction through an analysis module. Furthermore, the first wind force value is determined through the blade deformation amount, the second wind force value is determined through the impeller rotation speed, and the accuracy of the currently measured current wind force value is determined by comparing the first wind force value and the second wind force value. If the difference between the first wind force value and the second wind force value is less than the preset value, it is considered that the current wind force value is accurate enough.

[0034] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0035] Figure 1 It is a method step diagram of an offshore wind power monitoring method in an embodiment of this application;

[0036] Figure 2 It is a schematic connection diagram of a blade deformation measuring device, an impeller rotation speed measuring device, a wind direction measuring device and an analysis module in an embodiment of this application. Detailed Embodiments

[0037] The technical solution of the present invention will be further described below with reference to the drawings and embodiments.

[0038] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before the term cover the elements or objects listed after the term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0039] Embodiment:

[0040] The principle of wind power generation is to use wind power to drive the rotation of the windmill blades, and then increase the speed and raise the rotational speed to prompt the generator to generate electricity. Since wind power generation does not involve fuel issues and does not produce radiation or air pollution, it is a clean and environmentally friendly power generation method.

[0041] When using a wind power generation unit to generate electricity, in order to enable the wind power generation unit to adjust itself in a timely manner so that it can achieve the maximum power generation efficiency or make timely adjustments to special situations, it is necessary to monitor the wind force at sea in real time. The conventional monitoring method is to calculate the magnitude of the wind force based on the power generation efficiency of the wind power generation unit. If the wind power generation unit is worn or faulty, the measured wind force is not accurate.

[0042] Therefore, the present invention discloses a method for monitoring wind force at sea, which is applied with a blade deformation measuring device, an impeller rotational speed measuring device, and a wind direction measuring device. The blade deformation measuring device is used to measure the amount of blade deformation, the impeller rotational speed measuring device is used to measure the impeller rotational speed, and the wind direction measuring device is used to measure the wind direction.

[0043] There are preset a blade deformation-wind force comparison table and an impeller rotational speed-wind force comparison table. The blade deformation-wind force comparison table is used to judge the comparison relationship between blade deformation and wind force, and the impeller rotational speed-wind force comparison table is used to judge the comparison relationship between impeller rotational speed and wind force.

[0044] Refer to Figure 1 , the method includes:

[0045] S100, obtain the wind direction, and drive the yaw motor of the wind turbine to rotate according to the wind direction so that the impeller shaft is parallel to the wind direction.

[0046] In some embodiments of the present application, in order to be able to measure the wind direction more accurately, the wind direction measuring device is improved. The wind direction measuring device includes a first wind vane and a second wind vane. The first wind vane is connected with a first angle measuring device for measuring the first wind direction value, and the second wind vane is connected with a second angle measuring device for measuring the second wind direction value; if the difference between the first wind direction value and the second wind direction value is less than a preset value, then determine the average value between the first wind direction value and the second wind direction value as the current wind direction value.

[0047] S200, if the impeller shaft is parallel to the wind direction, obtain the amount of blade deformation, and determine the first wind force value according to the blade deformation-wind force comparison table.

[0048] In some embodiments of the present application, in order to be able to determine the wind force value according to the blade deformation amount comparison table, the content of the blade deformation amount comparison table is disclosed. The content of the blade deformation wind force comparison table includes several wind force value intervals connected end to end and several blade deformation amount intervals connected end to end, and each wind force value interval corresponds to a deformation amount interval one by one.

[0049] In some embodiments of the present application, in order to be able to determine the first wind force value, a method of applying the blade deformation amount comparison table is disclosed. The method of applying the blade deformation comparison table includes: obtaining the blade deformation amount, judging the blade deformation amount interval to which it belongs, judging the wind force value interval corresponding to the blade deformation amount interval, and taking the middle value of the determined wind force interval as the first wind force value.

[0050] S300, if the impeller shaft is parallel to the wind direction, obtain the impeller rotation speed, and determine the second wind force value according to the impeller rotation speed wind force comparison table.

[0051] In some embodiments of the present application, in order to be able to determine the wind force value according to the impeller rotation speed, the content of the impeller rotation speed comparison table is disclosed. The content of the impeller rotation speed wind force comparison table includes several impeller rotation speed intervals connected end to end and several wind force value intervals connected end to end, and each impeller rotation speed interval corresponds to a wind force value interval one by one.

[0052] In some embodiments of the present application, in order to be able to determine the second wind force value, a method of applying the rotation speed wind force comparison table is disclosed. The method of applying the rotation speed wind force comparison table includes: obtaining the impeller rotation speed, judging the impeller rotation speed interval to which the current impeller rotation speed belongs, judging the wind force value interval corresponding to the impeller rotation speed interval, and taking the middle value of the determined wind force value interval as the second wind force value.

[0053] S400, if the difference between the first wind force value and the second wind force value is less than or equal to the preset value, then determine the average value of the first wind force value and the second wind force value as the current wind force value.

[0054] If the difference between the first wind force value and the second wind force value is less than the preset value, it can be determined that the first wind force value calculated from the blade deformation amount and the second wind force value calculated from the impeller rotation speed are nearly the same, so both calculated values are accurate. However, during the long-term operation of the generator set, abnormal operation or wear may occur. In this case, the resistance to the impeller rotation may be relatively large, and due to the slower movement speed of the blade, the deformation of the blade becomes larger under the same wind force condition, resulting in an overestimated first wind force value. Due to the decrease in the impeller rotation speed, the determined second wind force value is underestimated, ultimately causing the difference between the first wind force value and the second wind force value to become larger. Based on this phenomenon, it is possible to determine whether there is an abnormality or wear in the wind turbine generator set by comparing the difference with the preset value.

[0055] In some embodiments of the present application, in order to accurately measure wind power even when there are abnormalities or wear in the generator set, the offshore wind power monitoring method is improved, and the method further includes:

[0056] If the difference C between the first wind power value A and the second wind power value B is greater than a preset value, then the current wind power value H is re-determined, and the current wind power value H = k1*A + k2*B is re-determined, where k1 is the first wind power value coefficient and k2 is the second wind power value coefficient.

[0057] In some embodiments of the present application, the method for determining the first wind power value coefficient k1 and the second wind power value coefficient k2 includes: a difference record table is set for the difference C between the first wind power value A and the second wind power value B, and corresponding k1 values and k2 values are associated with each difference C in the difference record table; the difference C is obtained, and based on the difference record table, the k1 value and the k2 value are determined.

[0058] An offshore wind power monitoring method disclosed in the present application determines the first wind power value by analyzing and judging the deformation amount of the blade, determines the second wind power value by analyzing and judging the rotational speed of the impeller, and determines the accuracy of the currently measured current wind power value by comparing the first wind power value and the second wind power value. If the difference between the first wind power value and the second wind power value is less than the preset value, it is determined that the current wind power value is accurate enough.

[0059] To further illustrate the technical solution of the present application, a specific application scenario is now provided.

[0060] Now, several wind turbine generator sets are set up offshore. In order to facilitate real-time adjustment and condition judgment of the wind turbine generator sets, it is now necessary to monitor the offshore wind power through the wind turbine generator sets.

[0061] To maximize the power generation efficiency, it is often necessary to change the attitude of the wind turbine generator set to make the impeller shaft parallel to the wind direction, thereby obtaining the maximum wind power.

[0062] To be able to obtain the maximum wind power, the generator set is provided with a wind direction measuring device. The wind direction is measured by the wind direction measuring device, and the yaw motor of the generator set is driven to rotate according to the wind direction, so that the wheel shaft is parallel to the wind direction.

[0063] This generator set is also internally equipped with a blade deformation measuring device, an impeller rotation speed measuring device, and an analysis module. Through the blade deformation measuring device, the amount of blade deformation is measured. Through the impeller rotation speed measuring device, the impeller rotation speed is measured. Through the analysis module, the amount of blade deformation, the impeller rotation speed, and the wind direction are analyzed. Furthermore, the first wind force value is determined through the amount of blade deformation, the second wind force value is determined through the impeller rotation speed, and by comparing the first wind force value and the second wind force value, the accuracy of the currently measured wind force value is determined. If the difference between the first wind force value and the second wind force value is less than the preset value, it is considered that the current wind force value is accurate enough.

[0064] In order to measure the first wind force value and the second wind force value, the analysis module is internally equipped with a blade deformation - wind force comparison table and an impeller rotation speed - wind force comparison table. The blade deformation - wind force comparison table is used to judge the correspondence between blade deformation and wind force. The impeller rotation speed - wind force comparison table is used to judge the correspondence between impeller rotation speed and wind force.

[0065] The analysis module determines the first wind force value and the second wind force value respectively according to the blade deformation comparison table and the impeller rotation speed comparison table. By comparing the difference between the first wind force value and the second wind force value, if the difference is less than the preset value, it is determined that the wind turbine generator set is working normally, and the current wind force value can be determined as the average value of the first wind force value and the second wind force value. If the difference is greater than the preset value, it is determined that the wind turbine generator set has a fault or excessive wear. In this case, in order to obtain the most accurate current wind force value, when determining the average value of the first wind force value and the second wind force value, the proportion between them is changed. The determination of the proportion can be set according to expert experience or can be determined through multiple experiments, so that the finally obtained current wind force value is more accurate.

[0066] In some embodiments of the present application, there is also disclosed an offshore wind monitoring system. Refer to Figure 2 , the system includes a blade deformation measuring device, an impeller rotation speed measuring device, a wind direction measuring device, and an analysis module.

[0067] The blade deformation measuring device is used to measure the amount of blade deformation.

[0068] The impeller rotation speed measuring device is used to measure the impeller rotation speed.

[0069] The wind direction measuring device is used to measure the wind direction.

[0070] The analysis module is used to analyze the amount of blade deformation, the impeller rotation speed, and the wind direction, and is internally equipped with a blade deformation - wind force comparison table and an impeller rotation speed - wind force comparison table.

[0071] The analysis module drives the yaw motor of the wind turbine to rotate according to the wind direction so that the impeller shaft is parallel to the wind direction. If the impeller shaft is parallel to the wind direction, the deformation amount of the blade is obtained, and according to the blade deformation-wind force comparison table, the first wind force value is determined. The impeller rotation speed is obtained, and according to the impeller rotation speed-wind force comparison table, the second wind force value is determined. If the difference between the first wind force value and the second wind force value is less than or equal to the preset value, the average value of the first wind force value and the second wind force value is determined as the current wind force value.

[0072] An offshore wind power monitoring system disclosed in this application measures the deformation amount of the blade through a blade deformation measuring device, measures the impeller rotation speed through an impeller rotation speed measuring device, measures the wind direction through a wind direction measuring device, and analyzes the deformation amount of the above-mentioned blade, the impeller rotation speed and the wind direction through an analysis module. Furthermore, the first wind force value is determined through the deformation amount of the blade, the second wind force value is determined through the impeller rotation speed, and the accuracy of the currently measured current wind force value is determined by comparing the first wind force value and the second wind force value. If the difference between the first wind force value and the second wind force value is less than the preset value, it is considered that the current wind force value is accurate enough.

[0073] The above-mentioned blade deformation monitoring device can be a conventional deformation sensor, the impeller rotation speed measuring device can be a conventional rotation speed measuring sensor device, and the analysis module can be a conventional processing module MCU.

[0074] Those skilled in the art should be able to realize that the modules and method steps of each example described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, computer software, or a combination of the two. The programs corresponding to the software modules and method steps can be placed in a random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the technical field. For the sake of clearly illustrating the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in the form of electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An offshore wind power monitoring method, characterized in that, There is a blade deformation measurement device, an impeller rotation speed measurement device, and a wind direction measurement device. The blade deformation measurement device is used to measure the deformation amount of the blade, the impeller rotation speed measurement device is used to measure the rotation speed of the impeller, and the wind direction measurement device is used to measure the wind direction; The method includes: presetting a blade deformation - wind force comparison table and an impeller rotation speed - wind force comparison table. The blade deformation - wind force comparison table is used to judge the comparison relationship between blade deformation and wind force, and the impeller rotation speed - wind force comparison table is used to judge the comparison relationship between impeller rotation speed and wind force; Obtain the wind direction, and drive the yaw motor of the wind turbine to rotate according to the wind direction so that the impeller shaft is parallel to the wind direction; If the impeller shaft is parallel to the wind direction, obtain the blade deformation amount, and determine the first wind force value A according to the blade deformation - wind force comparison table; If the impeller shaft is parallel to the wind direction, obtain the impeller rotation speed, and determine the second wind force value B according to the impeller rotation speed - wind force comparison table; If the difference between the first wind force value A and the second wind force value B is less than or equal to the preset value, then determine the average value of the first wind force value A and the second wind force value B as the current wind force value H.

2. The offshore wind power monitoring method according to claim 1, wherein The content of the blade deformation - wind force comparison table includes several wind force value intervals connected end - to - end and several blade deformation amount intervals connected end - to - end, and each wind force value interval corresponds to a deformation amount interval one by one.

3. The offshore wind power monitoring method according to claim 2, characterized in that, The method of applying the blade deformation - wind force comparison table includes: obtaining the blade deformation amount, judging the blade deformation amount interval it belongs to, judging the corresponding wind force value interval of the blade deformation amount interval, and taking the middle value of the determined wind force interval as the first wind force value.

4. A method for monitoring offshore wind power according to claim 1, characterized in that, The content of the impeller rotation speed - wind force comparison table includes several impeller rotation speed intervals connected end - to - end and several wind force value intervals connected end - to - end, and each impeller rotation speed interval corresponds to a wind force value interval one by one.

5. A method for monitoring offshore wind power according to claim 4, characterized in that, The method of applying the rotation speed - wind force comparison table includes: obtaining the impeller rotation speed, judging the impeller rotation speed interval that the current impeller rotation speed belongs to, judging the corresponding wind force value interval of the impeller rotation speed interval, and taking the middle value of the determined wind force value interval as the second wind force value.

6. The offshore wind power monitoring method according to claim 1, characterized in that The wind direction measurement device includes a first wind vane and a second wind vane. The first wind vane is connected with a first angle measurement device for measuring the first wind direction value, and the second wind vane is connected with a second angle measurement device for measuring the second wind direction value; If the difference between the first wind direction value and the second wind direction value is less than the preset value, then determine the average value between the first wind direction value and the second wind direction value as the current wind direction value.

7. A method for monitoring offshore wind power according to claim 1, characterized in that, The method further includes: if the difference C between the first wind force value A and the second wind force value B is greater than the preset value, then re - determine the current wind force value H. The re - determined current wind force value H = k1*A + k2*B, where k1 is the first wind force value coefficient and k2 is the second wind force value coefficient.

8. A method for monitoring offshore wind power according to claim 7, characterized in that, The method for determining the first wind force value coefficient k1 and the second wind force value coefficient k2 includes: there is a difference record table set for the difference C between the first wind force value A and the second wind force value B. In the difference record table, for each difference C, there is a corresponding k1 value and k2 value associated with it; obtain the difference C, and determine the k1 value and k2 value according to the difference record table.

9. An offshore wind monitoring system, characterized in that, The system includes: A blade deformation measurement device, which is used to measure the deformation amount of a blade; An impeller rotation speed measurement device, which is used to measure the impeller rotation speed; A wind direction measurement device, which is used to measure the wind direction; An analysis module, which is used to analyze the deformation amount of the blade, the impeller rotation speed and the wind direction, and has a blade deformation-wind force comparison table and an impeller rotation speed-wind force comparison table built in; The analysis module drives the yaw motor of the wind turbine to rotate according to the wind direction so that the impeller shaft is parallel to the wind direction. If the impeller shaft is parallel to the wind direction, the blade deformation amount is obtained, and according to the blade deformation-wind force comparison table, a first wind force value is determined. The impeller rotation speed is obtained, and according to the impeller rotation speed-wind force comparison table, a second wind force value is determined. If the difference between the first wind force value and the second wind force value is less than or equal to a preset value, the average value of the first wind force value and the second wind force value is determined as the current wind force value.

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