This patent application is the U.S. National Phase under 35 U.S.C. § 371 of International Application No. PCT/JP2019/026649, filed on Jul. 4, 2019, which claims the benefit of Japanese Patent Application No. 2019-039666, dated Mar. 5, 2019, and Japanese Patent Application No. 2018-133003, dated Jul. 13, 2018, the entire contents of each are hereby incorporated by reference in their entirety.
The present invention relates to a state monitoring device and a state monitoring system, and, more particularly, to a state monitoring device and a state monitoring system that monitor the state of an appliance to which the rotational torque is transmitted from a rotating body.
Conventionally, state monitoring devices and state monitoring systems are known which monitor the state of an appliance to which the rotational torque is transmitted from a rotating body. For example, Japanese Patent Laying-Open No. 2013-185507 (PTL 1) discloses a state monitoring system which determines whether diagnostic parameters calculated from vibration data of appliances (e.g., the main bearing and the step-up gearbox), which are included in a wind power generator, exceed thresholds, thereby diagnosing the states of the appliances. According to the state monitoring system, the thresholds are generated from the vibration data that is measured when operating conditions of the wind power generator satisfy diagnostic operating conditions, thereby allowing accurate abnormality diagnosis of the appliances included in the wind power generator.
The state monitoring system disclosed in PTL 1 calculates, as diagnostic parameters, a rotational frequency component and a harmonic frequency component of the rotational frequency from the vibration data of an appliance to which the rotational torque is transmitted from the rotating body, and performs the abnormality diagnosis on the appliance, using the diagnostic parameters. The calculation of the diagnostic parameter requires the rotational speed of the rotating body. Typically, the rotational speed is measured by a rotational sensor.
As with the state monitoring system disclosed in PTL 1, if the rotational speed of a rotating body is required for the abnormality diagnosis on an appliance to which the rotational torque is transmitted from the rotating body, and the rotational speed of the rotating body from the rotational sensor is not available due to, for example, a failure of the rotational sensor, the abnormality diagnosis on the appliance is difficult to be performed.
The present invention is made to solve problems as described above, and an object of the present invention is to provide the abnormality diagnosis with improved stability on an appliance to which the rotational torque is transmitted from a rotating body.
A state monitoring device according to the present invention monitors a state of an appliance to which a rotational torque of a rotating body is transmitted. The state monitoring device includes a storage unit and a controller. The storage unit pre-stores specific information produced from vibration data of an appliance, the specific information depending on a rotational speed of the rotating body. Using the rotational speed of the rotating body and the vibration data of the appliance, the controller performs an abnormality diagnosis on the appliance. Using the specific information, the controller estimates the rotational speed of the rotating body, the rotational speed being a rotational speed when the vibration data is measured.
In the state monitoring device according to the present invention, the rotational speed of the rotating body is estimated, using the specific information depending on the rotational speed of the rotating body, which is produced from the vibration data of the appliance. Thus, the abnormality diagnosis using the rotational speed of that rotating body will not be interrupted. According to the state monitoring device of the present invention, the abnormality diagnosis is performed with improved stability on the appliance to which the rotational torque is transmitted from the rotating body.
Hereinafter, embodiments of the present invention will be described, with reference to the accompanying drawings. Note that like reference signs are used to refer to like or corresponding parts in the drawings, and the description thereof will not be repeated.
The wind power generator 10 changes angles (hereinafter, also referred to as blade pitches) of the blades 30 relative to the direction of wind, in response to a velocity of the wind, to acquire a reasonable degree of rotation of the blades 30. The blade pitches are also controlled to start and stop the windmill. As a result, the amount of energy obtained from the wind can be adjusted. In high wind, for example, the wind-struck surfaces (also called surfaces or blade surfaces) of the blades are arranged in parallel with the direction of the wind to arrest the rotation of the windmill.
The main shaft 22 enters the nacelle 90 and is connected to the input axis of the step-up gearbox 40. The main shaft 22 is rotatably supported by the main bearing 60. The main shaft 22 transmits to the input axis of the step-up gearbox 40 a rotational torque which is generated by the blades 30 subjected to a wind force. The blades 30 are disposed on the tip of the main shaft 22 via the rotor head 20, convert the wind force into a rotational torque, and transmit the rotational torque to the main shaft 22.
The main bearing 60 is fixedly installed within the nacelle 90, rotatably supporting the main shaft 22. The main bearing 60 is configured of a rolling bearing, for example, a self-aligning bearing, a tapered roller bearing, a straight roller bearing, or a ball bearing, etc. Note that these bearings may be of a single-row or a double-row.
The acceleration sensor 70 is installed on the upper surface of the step-up gearbox 40, and measures vibration data of the step-up gearbox 40. The rotational sensor 77 is installed within the main bearing 60, and measures a rotational speed of the main shaft 22.
The step-up gearbox 40 is disposed between the main shaft 22 and the generator 50. The step-up gearbox 40 increases and outputs the rotational speed of the main shaft 22 to the generator 50. By way of example, the step-up gearbox 40 is configured of a gear increasing mechanism which includes a planetary gear, an intermediate shaft, and a high speed shaft, for example. Note that, although not shown specifically, multiple bearings for rotatably supporting the multiple shafts are also disposed within the step-up gearbox 40.
The generator 50 is connected to the output axis of the step-up gearbox 40, and generates power with the rotational torque received from the step-up gearbox 40. The generator 50 is configured of an induction generator, for example. Note that bearings for rotatably supporting rotors are also disposed within the generator 50.
The state monitoring device 80 is disposed within the nacelle 90, and receives the vibration data measured by the acceleration sensor 70, and the rotational speed measured by the rotational sensor 77. The state monitoring device 80 is connected to the acceleration sensor 70 and the rotational sensor 77 by wired cables not shown.
The acceleration sensor 70 is, for example, an acceleration sensor using a piezoelectric device. The acceleration sensor 70 measures and outputs the acceleration of a monitored target to the controller 81. The rotational sensor 77 measures and outputs the rotational speed of the main shaft 22 to the controller 81.
Using the vibration data measured by the acceleration sensor 70 and the rotational speed of the main shaft 22, the controller 81 performs abnormality diagnosis on the monitored target. The controller 81 includes a computer, such as a CPU (Central Processing Unit).
The storage unit 82 includes anon-volatile memory. The vibration data measured by the acceleration sensor 70 is saved to the storage unit 82. A gear mesh frequency of the gear included in the step-up gearbox 40 or information that is necessary to determine the gear mesh frequency (e.g., the number of gear teeth, and a ratio of the rotational speed of the gear to the rotational speed of the main shaft 22) is pre-stored in the storage unit 82. A result of the abnormality diagnosis performed by the controller 81 is displayed on the display unit 83.
As shown in
In S400, from the vibration data of the step-up gearbox 40, for example, a gear mesh frequency component and a harmonic frequency component of the mesh frequency are calculated as diagnostic parameters, and the abnormality diagnosis is performed using these diagnostic parameters. The rotational speed of the main shaft 22 is required to calculate the gear mesh frequency.
In the state monitoring system 1, if the rotational speed of the main shaft 22 is not available from the rotational sensor 77 due to a failure of the rotational sensor 77, it is difficult to perform the abnormality diagnosis on a monitored target.
Thus, in the state monitoring system 1, prior to the abnormality diagnosis, the rotational sensor 77 in the normal state measures vibration data of the monitored target, and the controller 81 produces a base spectral pattern, using the vibration data and the rotational speed measured by the rotational sensor 77. At the abnormality diagnosis, if the rotational speed of the main shaft 22 is not available from the rotational sensor 77, the controller 81 estimates the rotational speed of the main shaft 22, using the base spectral pattern. In the state monitoring system 1, owing to the rotating body's rotational speed estimation functionality, the abnormality diagnosis will not be interrupted by a failure of the rotational sensor 77 or the like. According to the state monitoring system 1, the abnormality diagnosis is performed with improved stability on an appliance to which the rotational torque is transmitted from the rotating body.
As shown in
The vibration value may be any value insofar as it is a parameter correlated to the vibrational energy. Examples of the vibration value include rms (Root Mean Square) or OA (Overall) value. Desirably, the vibration value is calculated from the vibration data whose frequency band is limited. Limiting the frequency band of the vibration data can, for example, prevent introduction of noise into the vibration data or reduce the impact of disturbance vibration on the vibration data. Thus, the abnormality diagnosis using the vibration value can be performed with improved accuracy.
In S230, the controller 81 determines whether the rotational sensor 77 is faulty. Specifically, if a fault condition is met that the absolute value of the rotational speed ωr is less than or equal to a threshold δ and the vibration value is greater than or equal to a threshold th, the controller 81 determines that the rotational sensor 77 is faulty. The absolute value of the rotational speed ωr being less than or equal to the threshold δ means that the absolute value of the rotational speed ωr is small to an extent that the rotational speed ωr can be approximated as zero. The vibration value being greater than or equal to the threshold th means that a monitored target is vibrating to a non-negligible extent, that is, the main shaft 22 is sufficiently rotated to transmit the rotational torque to the step-up gearbox 40 and the step-up gearbox 40 is vibrating to a non-negligible extent. The absolute value of the rotational speed ωr being less than or equal to the threshold δ in such a case means that the rotational sensor 77 is failing to measure the actual rotational speed of the main shaft 22.
If the fault condition is not met (NO in S230), the controller 81, in S240, sets a rotational speed for use in the abnormality diagnosis to the rotational speed ωr from the rotational sensor 77, and returns the process to the main routine. If the fault condition is met (YES in S230), the controller 81 performs the rotational speed estimation process in S250, sets the rotational speed for use in the abnormality diagnosis to the estimated rotational speed, and returns the process to the main routine.
[MATH 1]
In S254, using the transform coefficient vM as the rotational frequency of the main shaft 22, the controller 81 sets a rotational speed (r corresponding to that rotational frequency vM as the rotational speed for use in the abnormality diagnosis, and returns the process to the main routine. The rotational speed ωr is a rotational speed that is estimated as a rotational speed of the main shaft 22 when the vibration data is measured.
In the following, referring to
As shown in
Embodiment 1 has been described with reference to using an acceleration sensor as the vibration sensor. The vibration sensor is not limited to the acceleration sensor. For example, a velocity sensor, a displacement sensor, an AE (Acoustic Emission) sensor, an ultrasonic sensor, a temperature sensor, or an acoustic sensor may be used.
The controller included in the state monitoring system according to Embodiment 1 is also capable of converting the vibration data, obtained from the vibration sensor, to a vibration value, such as rms, a peak value, an OA value, or an average of vibration values in a predetermined interval. The controller is further capable of selecting a filter, such as a low-pass filter, a high-pass filter, or a band-pass filter, and limiting the frequency band in which the vibration data is measured.
While Embodiment 1 has been described with reference to the use of the rotational speed of the main shaft of the wind power generator for the abnormality diagnosis, the rotational speed used in the abnormality diagnosis is not limited to the rotational speed of this main shaft. Moreover, while Embodiment 1 has been described with reference to the step-up gearbox of the wind power generator as a target of the abnormality diagnosis, the target of the abnormality diagnosis is not limited to that step-up gearbox.
From the foregoing, according to the state monitoring device and the state monitoring system of Embodiment 1, the abnormality diagnosis can be performed with improved stability on an appliance to which the rotational torque is transmitted from the rotating body.
Embodiment 1 has been described with reference to the abnormality diagnosis system which includes the rotational sensor. Embodiment 2 will be described with reference to an abnormality diagnosis system which includes no rotational sensor.
Embodiment 2 is different from Embodiment 1 in that no rotational sensor is employed in Embodiment 2.
The controller 81B simulates processes corresponding to S11 through S15 of
From the foregoing, according to the state monitoring device and the state monitoring system of Embodiment 2, the abnormality diagnosis can be performed with improved stability on an appliance to which a rotational torque is transmitted from a rotating body. Moreover, according the state monitoring device and the state monitoring system of Embodiment 2, the rotational sensor is not required. Thus, cost reduction of the state monitoring system can be achieved.
Embodiments 1 and 2 have been described with reference to estimating the rotational speed of the rotating body, using a base spectral pattern. Embodiment 3 will be described with reference to estimating the rotational speed of the rotating body, using a relational expression derived by regression analysis of multiple combinations of a rotational speed of the rotating body and a vibration value of vibration data of an appliance.
According to a state monitoring device and a state monitoring system of Embodiment 3, the rotational speed of the rotating body can be estimated with accuracy even in the case where it is difficult to produce a base spectral pattern (e.g., the wind power generator does not include a step-up gearbox or mesh vibration of the gear of the step-up gearbox is extremely small relative to the vibration of the entirety of the wind power generator).
Embodiment 3 is different from Embodiment 1 in the process that is performed by a controller prior to the abnormality diagnosis and the rotational speed setting process. In other words, Embodiment 3 and Embodiment 1 are the same, except for including
As shown in
In S26, the controller determines whether the measurement count N is less than a scheduled count N1. If the measurement count N is less than the scheduled count N1 (YES in S26), the controller, in S27, changes the rotational speed ωr of the main shaft, and passes the process to S21.
If the measurement count N is greater than or equal to the scheduled count N1 (NO in S26), the controller, in S28, performs the regression analysis on multiple combinations of the vibration value stored in the storage unit and the rotational speed ωr, approximates the relational expression of the vibration value and the rotational speed ωr by multiple fitting methods, and passes the process to S29. The fitting methods used in S28 are, for example, polynomial fitting, exponential fitting, and linear fitting. In S29, the controller calculates R-squared R2 for each of the approximation expressions calculated in S28, saves to the storage unit an approximation expression that includes R-squared R2 closest to 1, among the approximation expressions obtained by the regression analysis, as a relational expression (specific information) of the vibration value and the rotational speed ωr, and returns the process to the main routine.
[MATH 3]
VP1=10−9·ωr3−2·10−7·ωr2+2·10−5·ωr+0.0017 (3)MATH 3
Note that the vibration value used in the estimation of the rotational speed ωr of the main shaft is not limited to the vibration value calculated from the vibration data of the step-up gearbox. For example, the vibration value may be calculated from vibration data of the main shaft.
[MATH 4]
VP2=−4·10−8·ωr+3·10−5·ωr2−10−3·ωr+0.0062 (4)MATH 4
Multiple relational expressions of the vibration value and the rotational speed co may be saved to the storage unit. For example, a relational expression of the vibration value of the step-up gearbox and the rotational speed co of the main shaft, and a relational expression of the vibration value of the main shaft and the rotational speed ωr of the main shaft may be saved to the storage unit.
As shown in
Note that, as with Embodiment 2, in the relational expression stored in the storage unit, the rotational speed for use in the abnormality diagnosis may be set to the rotational speed cc corresponding to the vibration value, without the use of a rotational sensor for the abnormality diagnosis. The abnormality diagnosis process in this case includes S260 of
From the foregoing, according to the state monitoring device and the state monitoring system of Embodiment 3, the abnormality diagnosis can be performed with improved stability on an appliance to which the rotational torque is transmitted from a rotating body.
Embodiments 1 to 3 have been described with reference to one acceleration sensor being included in the state monitoring system. Embodiment 4 will be described with reference to a state monitoring system including multiple acceleration sensors.
Embodiment 4 is different from Embodiment 1 in that the state monitoring system according to Embodiment 4 includes multiple acceleration sensors, and estimation of the rotational speed using a base spectral pattern and estimation of the rotational speed using a relational expression of a vibration value and the rotational speed are differentiated in the abnormality diagnosis. In other words,
The controller 81D receives vibration data from the acceleration sensors 70. The controller 81D performs the process illustrated in
As shown in
If the fault condition is not met (NO in S234), the controller 81D performs S240 and returns the process to the main routine. If the fault condition is met (YES in S234), the controller 81D, in S270, performs a rotational speed estimation process, sets the rotational speed for use in the abnormality diagnosis to the estimated rotational speed, and returns the process to the main routine.
In S272, the controller 81D determines whether the standard deviation of the rotational speeds ωf is greater than or equal to a threshold th2. If the standard deviation of the rotational speeds ωf is greater than or equal to the threshold th2 (YES in S272), the controller 81D determines that the level of noise included in the multiple pieces of vibration data is high and the accuracy of the rotational speed ωf is thus low, and passes the process to S273. In S273, using the relational expression stored in the storage unit, the controller 81D calculates a rotational speed ωc corresponding to each of the vibration values calculated in S224 of
If the standard deviation of the rotational speeds ωf is less than the threshold th2 (NO in S272), the controller 81D, in S275, sets the rotational speed for use in the abnormality diagnosis to the average of the rotational speeds ωf calculated in S273, and returns the process to the main routine. In S275, the rotational speed for use in the abnormality diagnosis may be set to the median of the rotational speeds ωf.
From the foregoing, according to the state monitoring device and the state monitoring system of Embodiment 4, the abnormality diagnosis can be performed with improved stability on an appliance to which a rotational torque is transmitted from a rotating body. Moreover, according to the state monitoring device and the state monitoring system of Embodiment 4, the estimation of the rotational speed using a base spectral pattern and the estimation of the rotational speed using a relational expression of the vibration value and the rotational speed are differentiated in the abnormality diagnosis, depending on a level of noise in the vibration data measured by the acceleration sensors, thereby inhibiting degradation in accuracy of the estimation of the rotational speed caused by the noise in the vibration data.
The presently disclosed embodiments are also expected to be combined and implemented as appropriate within a consistent range. The presently disclosed embodiments should be considered in all aspects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims, rather than by the description above. All changes which come within the meaning and range of equivalency of the appended claims are to be embraced within their scope.
Number | Date | Country | Kind |
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2018-133003 | Jul 2018 | JP | national |
2019-039666 | Mar 2019 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2019/026649 | 7/4/2019 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2020/013074 | 1/16/2020 | WO | A |
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Number | Date | Country | |
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20210293665 A1 | Sep 2021 | US |