A method for measuring wheel hub rotation speed

Abstract

The invention discloses a method for measuring the rotation speed of a wheel hub. A light source rangefinder is fixedly installed on the wheel hub main shaft of a wind turbine generator set, and a distance measuring disk is sleeved on the outer circumference of the wheel hub main shaft so as to be relatively rotatable. The distance measuring disk is provided with openings evenly spaced in the circumferential direction. The distance measuring disk is synchronously driven to rotate during the rotation of the wheel hub, the light source rangefinder is kept in a fixed state, and a light beam is irradiated on the distance measuring disk, so that the distance measuring light beam of the light source rangefinder is alternately irradiated on the opening position and the non-opening position of the distance measuring disk, and the frequency of the change of the light source distance measuring data is obtained. The rotation speed of the wheel hub is calculated based on the frequency of the change of the light source distance measuring data. The invention significantly improves the precision and accuracy of measuring the rotation speed of the wheel hub, and has a simple structure and low cost.

Description

Technical Field

[0001] The invention belongs to the field of wind turbine generator sets, and in particular relates to a method for measuring a hub rotation speed. Background Art

[0002] Accurate measurement of the hub speed of a wind turbine is one of the key technologies to ensure the normal operation of the wind turbine. Accurate measurement of the hub speed is of vital importance to ensuring the safe and stable operation of the wind turbine, improving power generation efficiency, and conducting fault diagnosis and prediction.

[0003] At present, the commonly used wind turbine hub speed measurement technologies include two methods: mechanical sensor measurement and encoder speed measurement. Among them, mechanical sensor measurement generally uses one or two independent proximity switches to detect the trigger object installed on the wind turbine main shaft and rotating with the main shaft. When the proximity switch and the trigger object are close to a certain distance, the internal circuit state of the proximity switch changes and generates an electrical signal. During the rotation of the wheel hub, the main shaft rotates with the wheel hub, and the triggering object periodically approaches the proximity switch, causing the proximity switch to periodically generate a pulse signal. By calculating the number of pulse signals per unit time, the rotation speed of the wheel hub can be obtained. Although this method is low-cost, the measurement result is limited and easily interfered with: the rotation speed is calculated by the pulse generated by the sensing object on the proximity switch sensing gear disk, and the measurement result has only two states, high level and low level, which are easily affected by interference or false triggering; and it is difficult to install: the proximity switch usually adopts an inductive proximity switch, which needs to maintain a small gap with the metal sensing surface for normal sensing, resulting in its installation position being limited by the wheel hub structure or the structure of the shaft installation; the encoder speed measurement method realizes rotation speed measurement by installing an encoder on the wheel hub. Although the measurement accuracy is high and the stability is good, the cost is relatively high.

[0004] Therefore, the applicant hopes to seek technical solutions to improve the above technical problems. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a method for measuring the rotational speed of a wheel hub, which significantly improves the precision and accuracy of measuring the rotational speed of the wheel hub, and has a simple structure and low cost.

[0006] To this end, the technical solution adopted in the present invention is as follows: A method for measuring the hub speed is provided, wherein a light source distance meter is fixedly installed on the hub main shaft of a wind turbine generator set, and a distance measuring disk is sleeved on the outer periphery of the hub main shaft so as to be relatively rotatable; wherein: The distance measuring disc is provided with openings evenly spaced in the circumferential direction; The distance measuring disc is synchronously driven to rotate during the rotation of the wheel hub, the light source rangefinder is kept in a fixed state, and a light beam is irradiated to the distance measuring disc, so that the distance measuring light beam of the light source rangefinder is alternately irradiated on the opening position and the non-opening position of the distance measuring disc, and the frequency of the change of the light source distance measuring data is obtained; The rotation speed of the wheel hub is calculated based on the frequency of the change of the light source distance measurement data.

[0007] Preferably, the number of the openings is 30-120, preferably 60; and / or the outer diameter of the ranging disc is in the range of 40-150 cm.

[0008] Preferably, the opening is in the shape of a circular hole; and / or the light source rangefinder is a laser rangefinder.

[0009] Preferably, the measurement method further comprises: recording and saving a light source ranging data curve obtained when the ranging disk rotates one circle under normal working conditions as a normal working distance curve; wherein, when carrying out wheel hub speed measurement, a real-time distance curve measured when the ranging disk rotates one circle is compared with a previously recorded normal working distance curve, and through the comparison operation, the measured abnormal data is corrected, and / or a corresponding alarm prompt is issued when abnormal data is found.

[0010] Preferably, when measuring the wheel hub speed, multiple groups of light source ranging data are continuously sampled and data processing is performed on them, wherein a single group of light source ranging data is measured when the ranging disk rotates one circle; The data processing includes: removing abnormal values, excessively large values ​​and excessively small values ​​in each group of light source ranging data, and using previous values ​​or subsequent values ​​to replace abnormal values; and performing recursive averaging on multiple groups of light source ranging data obtained by sampling to reflect the changing trend of the data.

[0011] Preferably, when Smax+ Ø≥Smea≥S1+Ø, it is judged that the ranging beam of the light source rangefinder falls on the opening position of the ranging disk; when S1+ Ø>Smea≥S1-Ø, it is judged that the ranging beam of the light source rangefinder falls on the non-opening position of the ranging disk; wherein Smax is the maximum light source ranging data measured by the light source rangefinder when the ranging disk rotates one circle under normal working conditions, S1 is the minimum light source ranging data measured by the light source rangefinder when the ranging disk rotates one circle under normal working conditions; Smea is the real-time light source ranging data measured by the light source rangefinder in the current working state; Ø is a settable error bias value.

[0012] Preferably, when it is found that Smea>Smax+Ø or Smea<S1-Ø, it is determined to be abnormal data and a corresponding alarm prompt is issued.

[0013] Preferably, the sampling period of the light source rangefinder is 2-100 ms, more preferably 2-50 ms.

[0014] Preferably, it is determined that the ranging light beam of the light source rangefinder falls on the opening position of the ranging disk as one pulse. Under high-speed working conditions, the speed calculation formula is: n1=60*m / (p*t), wherein n1 is the high-speed working speed (unit: revolutions per minute RPM), m is the number of counted pulses within the detection time t, p is the number of pulses output per rotation of the ranging disk, and t is the detection time in seconds (s); under low-speed working conditions, the speed calculation formula is: n2=p*t1+(p-1)*t2, wherein n2 is the low-speed working speed (unit: revolutions per minute RPM), p is the number of pulses output per rotation of the ranging disk, t1 is the time to pass through the opening position, and t2 is the time to pass through the non-opening position; The high-speed operating speed n1 and the low-speed operating speed n2 are calculated simultaneously, and the real-time speed of the hub is determined based on the weight distribution of each speed.

[0015] Preferably, at 0 speed, the weight x2 of the low speed condition speed n2 is 1 at most, and the weight x1 of the high speed condition speed n1 is 0 at most; as the speed increases, the weight x2 of the low speed condition speed n2 gradually decreases, and the weight x1 of the high speed condition speed n1 gradually increases; when the set maximum speed n is reached, max , the weight x2 of the low-speed operating speed n2 is reduced to 0, and the weight x1 of the high-speed operating speed n1 is increased to 1; wherein, x1+x2=1; the real-time speed n of the wheel hub is n1*x1+n2*x2.

[0016] The present invention fixes a light source rangefinder on the hub main shaft of the wind turbine generator set, and at the same time, a distance measuring disk is relatively rotatably sleeved on the outer periphery of the hub main shaft, and cooperates with the fixed light source rangefinder, and utilizes the periodic change of the distance measured by the light source rangefinder (that is, the light source distance measuring data) when the hub drives the distance measuring disk to rotate to automatically calculate the hub rotation speed, which changes the traditional measurement method and significantly improves the precision and accuracy of measuring the hub rotation speed, which is different from the simple high-level and low-level pulse curves of the traditional mechanical sensing measurement method; the structure provided by the present invention is simple and low in cost, and compared with the strict requirements of the mechanical sensing measurement method on the installation position due to the sensing gap, the installation is more flexible and less restricted by the structure; in addition, in the data processing, the present invention automatically records the change and law of the sampled light source distance measuring data, excludes abnormal data, corrects the sampled data, relies on comparative analysis of the generated complex curve reflecting the distance change, and checks the rotation angle, position and rotation speed, so as to further improve the measurement precision and accuracy of the present invention, and has a strong fault analysis and judgment ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the measurement structure of the hub speed in the specific implementation mode of the present application. DETAILED DESCRIPTION

[0018] The embodiment of the present invention discloses a method for measuring the rotation speed of a wheel hub. A light source rangefinder is fixedly installed on the main shaft of the wheel hub of a wind turbine generator set, and a distance measuring disk is relatively rotatably sleeved on the outer circumference of the main shaft of the wheel hub. The distance measuring disk is provided with openings evenly spaced in the circumferential direction. During the rotation of the wheel hub, the distance measuring disk is synchronously driven to rotate, the light source rangefinder remains in a fixed state, and a light beam is irradiated to the distance measuring disk, so that the distance measuring light beam of the light source rangefinder is alternately irradiated on the opening position and the non-opening position of the distance measuring disk, and the frequency of the change of the light source distance measuring data is obtained; based on the frequency of the change of the light source distance measuring data, the rotation speed of the wheel hub is calculated.

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] See also Figure 1 As shown, this embodiment provides a method for measuring the hub rotation speed, wherein a light source rangefinder 2 is fixedly mounted on the hub main shaft 1 of the wind turbine generator set, and a rangefinder disc 3 is relatively rotatably sleeved on the outer circumference of the hub main shaft 1; wherein the rangefinder disc 3 is provided with openings 3a uniformly spaced in the circumferential direction; preferably, in this embodiment, the openings 3a are in the shape of circular holes; the number of the openings 3a is preferably 30-120 (more preferably 60); Figure 1 The number of openings 3a shown is 32; the outer diameter of the distance measuring disk 3 is 40-150 cm; preferably, in this embodiment, the light source distance meter 2 is a laser distance meter.

[0021] In this embodiment, the ranging disk 3 is synchronously driven to rotate during the rotation of the wheel hub, the light source rangefinder 2 remains fixed, and the ranging disk 3 is irradiated with a light beam, so that the ranging light beam of the light source rangefinder 2 alternately irradiates the open hole position and the non-open hole position of the ranging disk 3, and the frequency of the change of the light source ranging data is obtained; based on the frequency of the change of the light source ranging data, the rotation speed of the wheel hub is calculated.

[0022] Preferably, in this embodiment, the measuring method further comprises: recording and saving the light source ranging data curve obtained when the ranging disk 3 rotates one circle under normal working conditions as a normal working distance curve; wherein, when the wheel hub speed measurement is carried out, the real-time distance curve measured when the ranging disk 3 rotates one circle is compared with the normal working distance curve recorded previously, and through the comparison operation, the measured abnormal data is corrected, and / or a corresponding alarm prompt is made when abnormal data is found; preferably, in this embodiment, when Smax+ Ø≥Smea≥S1+Ø, it is judged that the ranging light beam of the light source rangefinder 2 falls on the opening position of the ranging disk 3; when S1+ When Ø>Smea≥S1-Ø, it is determined that the ranging beam of the light source rangefinder 2 falls on the non-opening position of the ranging disk 3; wherein Smax is the maximum light source ranging data measured by the light source rangefinder when the ranging disk 3 rotates one circle under normal working conditions, and S1 is the minimum light source ranging data measured by the light source rangefinder when the ranging disk 3 rotates one circle under normal working conditions; Smea is the real-time light source ranging data measured by the light source rangefinder in the current working state; Ø is a settable error bias value; preferably, in this embodiment, when it is found that Smea>Smax+ Ø or Smea<S1-Ø, it is determined to be abnormal data and a corresponding alarm prompt is made (specifically, it can be done by outputting an alarm signal, of course, other suitable alarm methods can also be used, and this embodiment does not specifically limit it).

[0023] Preferably, in this embodiment, when the wheel hub speed measurement is carried out, ten groups of light source ranging data are continuously sampled (wherein, preferably, the sampling period of the light source ranging instrument 2 is 2-50ms), and data processing is performed on them, wherein a single group of light source ranging data is measured when the ranging disk 3 rotates one circle; the data processing includes: eliminating abnormal values, excessive values ​​and excessively small values ​​in each group of light source ranging data, and using the previous value or the next value to replace the abnormal value; and performing recursive averaging on the multiple groups of light source ranging data obtained by sampling to reflect the changing trend of the data.

[0024] In order to further illustrate the measurement implementation process of the present application, based on the above implementation scheme, the present application specifically proposes the following wheel hub speed measurement process example: Embodiment 1:

[0025] 1.1 The distance from the light source rangefinder to the non-opening position on the outer circumference of the rangefinder disk is 48-50 cm.

[0026] 1.2 When rotating one circle (i.e. one rotation), the distance from the light source rangefinder to the opening position is: 100-200 cm.

[0027] 1.3 Adjustable error offset value (Ø): 2 cm.

[0028] 1.4 Number of holes on the distance measuring disc (i.e. the number of holes): 60.

[0029] 1.5 Set the detection time (t): 500 milliseconds (0.5 seconds).

[0030] 1.6 Number of pulses detected within the set time (m): 3.

[0031] Then when the ranging data is 98-202cm, it is irradiated at the opening position (that is, the ranging beam falls at the opening position), which is one pulse; According to the calculation formula of high-speed operating speed n1: n1=60*m / (p*t); substitute the given value: n1=60*3 / (60*0.5)= 6 revolutions per minute RPM. Embodiment 2:

[0032] 2.1 Distance from the light source rangefinder to the outer circumference of the ranging disk: 48-50 cm.

[0033] 2.2 When rotating one circle (i.e. one rotation), the distance from the light source rangefinder to the outside of the hole is: 100-200 cm.

[0034] 2.3 Adjustable error offset value (Ø): 2 cm.

[0035] 2.4 Number of holes on the distance measuring disc (i.e. the number of holes): 60.

[0036] Then when the ranging data is 46-52cm, it is irradiated at the non-opening position (that is, the ranging beam falls on the non-opening position); when the ranging data is 98-202cm, it is irradiated at the opening position (that is, the ranging beam falls on the opening position); the measured continuous irradiation time t1 at the opening position is 240ms; the measured continuous irradiation time t2 at the non-opening position is 170ms; According to the formula for calculating the speed n2 under low-speed conditions: n2=p*t1+(p-1)*t2; substitute the given value n2=60*0.24+59*0.17=5.84 rpm.

[0037] Finally, the real-time speed of the hub can be calculated based on the weight distribution of the actual high-speed working speed n1 and the low-speed working speed n2; for example, the weight distribution of the current speed is: high-speed working speed n1=0.5 ， Low speed condition speed n2=0.5; Through the calculation formula: the real-time rotation speed of the wheel hub n=n1*x1+n2*x2, it is finally concluded that the real-time rotation speed of the wheel hub n=6*0.5+5.84*0.5=5.92 revolutions per minute RPM.

[0038] It should also be noted that, since the distances from the light source rangefinder to each hole opening are inconsistent, this embodiment can also sort the distances from the light source rangefinder to the outside of each hole; wherein the number of pulses between the hole position with the maximum distance and the hole position with the minimum distance is fixed; by reading the number of pulses in this interval, it is possible to determine whether the sampling is wrong.

[0039] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0040] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for measuring wheel hub rotation speed, characterized in that: A light source distance meter is fixedly mounted on the hub main shaft of the wind turbine generator set, and a distance measuring disk is sleeved on the outer periphery of the hub main shaft so as to be relatively rotatable; wherein, The distance measuring disc is provided with openings evenly spaced in the circumferential direction; The distance measuring disc is synchronously driven to rotate during the rotation of the wheel hub, the light source rangefinder is kept in a fixed state, and a light beam is irradiated to the distance measuring disc, so that the distance measuring light beam of the light source rangefinder is alternately irradiated on the opening position and the non-opening position of the distance measuring disc, and the frequency of the change of the light source distance measuring data is obtained; The rotation speed of the wheel hub is calculated based on the frequency of the change of the light source distance measurement data.

2. The method for measuring the wheel hub speed according to claim 1, characterized in that: The number of the openings is 30-120, preferably 60; and / or the outer diameter of the distance measuring disc is in the range of 40-150 cm.

3. The method for measuring the wheel hub speed according to claim 1, characterized in that: The opening is in the shape of a circular hole; and / or the light source distance meter is a laser distance meter.

4. The method for measuring the wheel hub speed according to claim 1, characterized in that: The measuring method further comprises: recording and saving a light source distance measurement data curve obtained when the distance measuring disk rotates one circle under normal working conditions as a normal working distance curve; wherein, when measuring the wheel hub speed, a real-time distance curve measured when the distance measuring disk rotates one circle is compared with a previously recorded normal working distance curve, and through the comparison operation, the measured abnormal data is corrected, and / or a corresponding alarm prompt is issued when abnormal data is found.

5. The method for measuring the wheel hub speed according to claim 4, characterized in that: When measuring the wheel hub speed, multiple groups of light source distance measurement data are continuously sampled and processed, wherein a single group of light source distance measurement data is measured when the distance measurement disk rotates one circle; The data processing includes: removing abnormal values, excessively large values ​​and excessively small values ​​in each group of light source ranging data, and using previous values ​​or subsequent values ​​to replace abnormal values; and performing recursive averaging on multiple groups of light source ranging data obtained by sampling to reflect the changing trend of the data.

6. The method for measuring the wheel hub speed according to claim 4, characterized in that: When Smax+ Ø≥Smea≥S1+Ø, it is determined that the ranging beam of the light source rangefinder falls on the opening position of the ranging disk; when S1+ Ø>Smea≥S1-Ø, it is determined that the ranging beam of the light source rangefinder falls on the non-opening position of the ranging disk; wherein Smax is the maximum light source ranging data measured by the light source rangefinder when the ranging disk rotates one circle under normal working conditions, S1 is the minimum light source ranging data measured by the light source rangefinder when the ranging disk rotates one circle under normal working conditions; Smea is the real-time light source ranging data measured by the light source rangefinder in the current working state; Ø is a settable error bias value.

7. The method for measuring the wheel hub speed according to claim 6, characterized in that: When it is found that Smea>Smax+Ø or Smea<S1-Ø, it is judged as abnormal data and a corresponding alarm prompt is issued.

8. The method for measuring the wheel hub speed according to claim 5, characterized in that: The sampling period of the light source rangefinder is 2-100 ms, more preferably 2-50 ms.

9. The method for measuring the wheel hub speed according to claim 1, characterized in that: It is determined that the ranging light beam of the light source rangefinder falls on the opening position of the ranging disk as one pulse. Under high-speed working conditions, the speed calculation formula is: n1=60*m / (p*t), wherein n1 is the high-speed working speed (unit: revolutions per minute RPM), m is the number of counted pulses within the detection time t, p is the number of pulses output per rotation of the ranging disk, and t is the detection time in seconds (s); under low-speed working conditions, the speed calculation formula is: n2=p*t1+(p-1)*t2, wherein n2 is the low-speed working speed (unit: revolutions per minute RPM), p is the number of pulses output per rotation of the ranging disk, t1 is the time to pass through the opening position, and t2 is the time to pass through the non-opening position; The high-speed operating speed n1 and the low-speed operating speed n2 are calculated simultaneously, and the real-time speed of the hub is determined based on the weight distribution of each speed.

10. The method for measuring the wheel hub speed according to claim 9, characterized in that: At 0 speed, the weight x2 of the low speed condition speed n2 is 1 at the highest, and the weight x1 of the high speed condition speed n1 is 0 at the lowest; as the speed increases, the weight x2 of the low speed condition speed n2 gradually decreases, and the weight x1 of the high speed condition speed n1 gradually increases; when the set maximum speed n is reached, max , the weight x2 of the low-speed operating speed n2 is reduced to 0, and the weight x1 of the high-speed operating speed n1 is increased to 1; wherein, x1+x2=1; the real-time speed n of the wheel hub is n= n1*x1+ n2*x2.

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