CN114295374A - Crack monitoring system and method for variable-pitch bearing and wind generating set - Google Patents
Crack monitoring system and method for variable-pitch bearing and wind generating set Download PDFInfo
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Abstract
The utility model provides a crack monitoring system and method and wind generating set of change oar bearing, crack monitoring system includes: a signal generator configured to generate an excitation signal; a detection circuit including a first sensor and a second sensor that receive the excitation signal, and outputting a first detection signal and a second detection signal according to an on-off state of the first sensor and the second sensor, wherein the first sensor and the second sensor are provided on an outer circumferential surface of the same pitch bearing, the first sensor itself changes to an off state in response to occurrence of a first degree of crack on the outer circumferential surface of the pitch bearing, and the second sensor itself changes to an off state in response to occurrence of a second degree of crack on the outer circumferential surface of the pitch bearing, wherein a gap of the second degree of crack is larger than a gap of the first degree of crack; processing circuitry generates an output signal indicative of a state of the pitch bearing based on the first detection signal and the second detection signal.
Description
Technical Field
The invention relates to the field of wind power, in particular to a crack monitoring system and method for a pitch bearing and a wind generating set.
Background
In a wind generating set, wind energy is converted into kinetic energy through the rotation of blades, the wind generating set is expensive in manufacturing cost, severe in using environment and complex in working condition, and a variable pitch bearing is cracked frequently under the comprehensive action of various loads such as vibration, torsion, shearing, extrusion and bending load for a long time in the running process.
If the fault is not found timely, equipment accidents of the wind generating set can be caused, huge economic losses are caused, and personal injury accidents can be caused seriously.
The failure mode of the variable-pitch bearing is cracking, and the variable-pitch bearing can be divided into early cracks, medium cracks and late cracks according to the development of the cracks.
After the variable-pitch bearing generates cracks, the stress is applied due to the constraint of the bolts, the cracks continue to expand to the reinforcing ring, the reinforcing ring cracks, grease leaks, the cracks continue to expand, and finally the blade can fall.
In order to ensure the safe operation of the wind generating set, the state of a variable pitch bearing of the wind generating set needs to be monitored. The lightning protection anti-jamming capability of the existing monitoring system circuit is poor, so that the failure rate is high and the false alarm rate is high.
Disclosure of Invention
One of the objectives of the present disclosure is to provide a crack monitoring system and a crack monitoring method that are capable of monitoring the state of a pitch bearing.
One of the objectives of the present disclosure is to provide a crack monitoring system and a crack monitoring method capable of monitoring the crack development state of a pitch bearing in real time.
According to a first aspect of the present disclosure, there is provided a crack monitoring system of a pitch bearing, the crack monitoring system comprising: a signal generator configured to generate an excitation signal; a detection circuit including a first sensor and a second sensor that receive the excitation signal, and outputting a first detection signal and a second detection signal according to an on-off state of the first sensor and the second sensor, wherein the first sensor and the second sensor are provided on an outer circumferential surface of the same pitch bearing, the first sensor itself changes to an off state in response to occurrence of a first degree of crack on the outer circumferential surface of the pitch bearing, and the second sensor itself changes to an off state in response to occurrence of a second degree of crack on the outer circumferential surface of the pitch bearing, wherein a gap of the second degree of crack is larger than a gap of the first degree of crack; processing circuitry generates an output signal indicative of a state of the pitch bearing based on the first detection signal and the second detection signal.
According to a second aspect of the present disclosure, a wind park is provided, comprising a crack monitoring system of a pitch bearing as described above.
According to a third aspect of the present disclosure, there is provided a crack monitoring method for a pitch bearing, the crack monitoring method comprising: applying excitation signals to a first sensor and a second sensor, wherein the first sensor and the second sensor are arranged on the outer circumferential surface of the same pitch bearing, the first sensor itself changing to an open state in response to the occurrence of a first degree of cracking on the outer circumferential surface of the pitch bearing, the second sensor itself changing to an open state in response to the occurrence of a second degree of cracking on the outer circumferential surface of the pitch bearing, wherein the second degree of cracking has a larger gap than the first degree of cracking; detecting first and second detection signals output by the first and second sensors; and determining the state of the pitch bearing according to the first detection signal and the second detection signal.
According to the crack monitoring system and the crack monitoring method, early warning such as warning, severe warning and shutdown can be timely and graded after the variable-pitch bearing cracks.
According to the crack monitoring system and the crack monitoring method disclosed by the embodiment of the disclosure, the enameled wire does not need to be frequently replaced.
According to the crack monitoring system and the crack monitoring method, the false alarm rate can be reduced.
Additional aspects and/or advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept.
Drawings
The above and other aspects, features and other advantages of the present disclosure will become apparent and more readily appreciated from the following detailed description of the exemplary embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a block diagram illustrating a crack monitoring system of a pitch bearing according to a first embodiment of the present disclosure.
FIG. 2 is a block diagram illustrating a crack monitoring system of a pitch bearing according to a second embodiment of the present disclosure.
Fig. 3 is a circuit diagram illustrating a detection circuit according to an embodiment of the present disclosure.
FIG. 4 is a schematic diagram illustrating a control approach of a crack monitoring system of a pitch bearing according to an embodiment of the present disclosure.
FIG. 5 is a flow chart illustrating a crack monitoring method of a pitch bearing according to an embodiment of the present disclosure.
Detailed Description
Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be understood that in the following description of the embodiments and the accompanying drawings, the same or similar components are denoted by the same reference numerals, and overlapping description is omitted.
The crack monitoring system can be used for monitoring the crack development state of the variable pitch bearing in real time, and can perform early warning in different grades in time after cracking, such as warning and shutdown.
Crack monitoring systems according to embodiments of the present disclosure may reduce failure rates and false alarm rates.
Fig. 1 is a block diagram showing a crack monitoring system of a pitch bearing according to a first embodiment of the disclosure, fig. 2 is a block diagram showing a crack monitoring system of a pitch bearing according to a second embodiment of the disclosure, and fig. 3 is a circuit diagram showing a detection circuit according to an embodiment of the disclosure.
As shown in FIG. 1, a crack monitoring system for a pitch bearing according to embodiments of the present disclosure may include a signal generator 20, detection circuitry 30, and processing circuitry 40.
The signal generator 20 may generate an excitation signal, and the excitation signal generated by the signal generator 20 may be controlled by the processing circuit 40. The type of excitation signal emitted by the signal generator 20 is not particularly limited.
The detection circuit 30 may include a sensor 33 that receives the excitation signal, the detection circuit 30 may include a plurality of sensors, for example, a first sensor and a second sensor, and the detection circuit 30 may output a first detection signal and a second detection signal according to on-off states of the first sensor and the second sensor.
The first and second sensors may each be disposed on an outer circumferential surface of the pitch bearing, and the first and second sensors themselves change to an off state in response to the occurrence of a crack on the outer circumferential surface of the pitch bearing.
The first and second sensors may be provided on the same outer circumferential surface of the pitch bearing, the first and second sensors themselves changing to an off state in sequence in response to the occurrence of different degrees of cracking on the outer circumferential surface of the pitch bearing.
For example, the first sensor itself changes to the disconnected state in response to the occurrence of a first degree of cracking on the outer circumferential surface of the pitch bearing, and the second sensor itself changes to the disconnected state in response to the occurrence of a second degree of cracking on the outer circumferential surface of the pitch bearing, wherein the second degree of cracking has a greater gap than the first degree of cracking.
The detection circuit 30 may further include a third sensor that receives the excitation signal, and the detection circuit 30 may output a third detection signal according to an on-off state of the third sensor.
Similarly, the first sensor, the second sensor and the third sensor are arranged on the same outer circumferential surface of the pitch bearing, the third sensor may have a similar structure as the first sensor, and the third sensor may itself change to an off-state in response to the occurrence of a third degree of cracking on the outer circumferential surface of the pitch bearing.
The cracks of different degrees have different sizes, the cracks of the third degree are larger than the cracks of the second degree, and the cracks of the second degree are larger than the cracks of the first degree.
That is, the plurality of sensors may respectively detect the extent of cracking of cracks on the outer circumferential surface of the same pitch bearing.
As an example, the excitation signal generated by the signal generator may be directly applied across the first sensor, the second sensor, and the third sensor, the excitation signal generated by the signal generator may be coupled across the first sensor, the second sensor, and the third sensor, the processing circuitry 40 may be configured to receive the detection signal when the first sensor changes to the off state, which may mean that the pitch bearing has a first degree of cracking, and the processing circuitry 40 may be configured to receive the detection signal when the second sensor changes to the off state, which may mean that the pitch bearing has a second degree of cracking.
When the third sensor is provided, the processing circuitry 40 may not receive the detection signal when the third sensor changes to the off-state, which means that the pitch bearing has a third degree of cracking.
Thus, according to embodiments of the present disclosure, a crack monitoring system may monitor the state of development of a crack.
Each of the first, second, and third sensors may be constructed using a material having electrical conductivity, relatively high sensitivity, and relatively low ductility such that when different degrees of cracking propagate to the outer circumferential surface of the pitch bearing, each of the first, second, and third sensors may change from an on state to an off state upon the occurrence of different degrees of cracking, and thus the on/off state of the first, second, and third sensors may be used to determine whether and to what extent cracking has occurred on the pitch bearing.
As an example, each of the first sensor, the second sensor, and the third sensor may be a varnished wire sensor, and in particular, each of the first sensor, the second sensor, and the third sensor may be configured using varnished wires of different wire diameters. Alternatively, each of the first sensor, the second sensor and the third sensor may be implemented by at least one of a copper foil, an aluminum foil and a tin foil, but is not limited thereto.
Further, each of the first sensor, the second sensor, and the third sensor may be configured to implement an active alarm after sensing a zone crack.
As an example, the first sensor, the second sensor, and the third sensor may correspond to individual enamel wires respectively corresponding to the individual enamel wire sensors.
Each of the first sensor, the second sensor, and the third sensor may be implemented by a varnished wire sensor. Four enameled wires can be arranged in each set of enameled wire sensor, three of the enameled wires can correspond to three sensors, the fourth enameled wire can be an excitation generation enameled wire, the three enameled wires are disconnected in sequence, and the three enameled wires can be sequentially disconnected according to the sequence of the first sensor, the second sensor and the third sensor, so that a crack of 1mm can be detected firstly, then a crack of 5mm is detected, and finally a crack state is monitored according to the sequence of 8-10 mm cracks.
When the crack of the variable-pitch bearing reaches 8-10 mm, the whole machine is stopped, and the bearing needs to be processed. In the whole process, the enameled wire does not need to be repeatedly replaced, and the monitoring of the pitch bearing in the whole life cycle can be realized only by once construction.
As an example, the fourth enameled wire is used for applying the excitation signal, and 4 enameled wires can be laid adjacently. After the fourth enameled wire applies an excitation signal, due to crosstalk, coupling voltages can simultaneously appear on the three enameled wires, and if one of the three enameled wires is broken, the coupling voltage can be greatly reduced, so that software can recognize the coupling voltage.
As an example, the first sensor, the second sensor and the third sensor may also be of different types.
When the detection circuit 30 includes a first sensor and a second sensor, the first sensor may detect a crack of, for example, 5mm and the second sensor may detect a crack of, for example, 8mm to 10 mm.
The processing circuitry 40 may generate an output signal indicative of a state of the pitch bearing based on the first detection signal and the second detection signal. When the detection circuit outputs the third detection signal, the processing circuit 40 may generate an output signal indicative of the state of the pitch bearing based on the first, second and third detection signals.
The processing circuitry 40 may generate a first output signal indicating that the pitch bearing is cracked in response to the first sensor being in the disconnected state and the second sensor not being in the disconnected state.
The processing circuitry 40 may generate a second output signal indicating that the pitch bearing requires shutdown maintenance in response to the second sensor being in the disconnected state.
When the detection circuit 30 includes each of the first sensor, the second sensor and the third sensor implemented by the enamel wire sensor, the first sensor may detect cracks of 1mm, the second sensor may detect cracks of 5mm, and the third sensor may detect cracks of 8mm to 10 mm.
The processing circuitry 40 may generate a first output signal indicating that the pitch bearing has generated a first degree of cracking in response to the first sensor being in the disconnected state and the second sensor not being in the disconnected state.
The processing circuitry 40 may generate a second output signal indicating that the pitch bearing has generated a second degree of cracking in response to the second sensor being in the disconnected state and the third sensor not being in the disconnected state.
The processing circuitry 40 may generate a third output signal indicating that the pitch bearing requires shutdown maintenance in response to the third sensor being in the disconnected state.
When the detection circuitry 30 comprises more sensors, the processing circuitry 40 may generate output signals indicative of the state of the pitch bearing based on the respective detection signals output by the detection circuitry, such that the state of development of cracks of the pitch bearing may be monitored.
As shown in fig. 2, the signal generator 20 may generate excitation signals applied to the first sensor, the second sensor, and the third sensor at predetermined periods under the control of the processing circuit 40.
As shown in fig. 2, the detection circuit 30 may include a switching circuit 31, and the switching circuit 31 may be electrically connected between the sensor 33 and the processing circuit 40 to make or break the electrical connection of the sensor to the processing circuit 40.
The switching circuit 31 may include a first switching circuit electrically connected between the first sensor and the processing circuit 40 and a second switching circuit electrically connected between the second sensor and the processing circuit 40 and turned on in response to the first sensor being in an off state during monitoring.
As an example, the switching circuit 31 may include a third switching circuit that may be electrically connected between the third sensor and the processing circuit 40 and that is turned on in response to the second sensor being in an off state during monitoring. That is, the switch circuit 31 may be turned on sequentially at different monitoring periods.
Referring to fig. 3, each of the switching circuits 31 may include a switching device 311 and an electrical control device 312, the normally open contact of the switching device 311 being connected between the corresponding sensor and the processing circuit 40, and the electrical control device 312 being electrically connected to the control terminal of the switching device 311 to control the opening and closing of the normally open contact of the switching device 311.
As shown in fig. 3, the switching device 311 is, for example, a relay K1, but is not limited thereto, and may be any device that can perform a switching function. In this example, the relay K1 has two pairs of normally open contacts with which the respective sensor and processing circuit 40 is connected via connector J1, VCC being the voltage provided by the power supply of the relay K1.
The electric control device 312 is, for example, a transistor Q1, but is not limited thereto as long as the function of electric control can be realized, for example, a MOSFET, an IGBT, or the like. In this example, the collector of the transistor Q1 is electrically connected to the control terminal of K1, the emitter of the transistor Q1 is electrically connected to ground GND, and the transistor Q1 is controlled by a processing circuit 40 (to be described later).
On each monitoring circuit, a switching circuit may be provided, that is, when the detection circuit includes two sensors, two switching circuits may be provided, and when the detection circuit includes three sensors, three switching circuits may be provided, and the configuration of each switching circuit may be the same.
A connector 35 may also be provided between the switching circuit 31 and the sensor 33, and the connector 35 may include a first connector, a second connector, and a third connector, each of which may have the same configuration and may each correspond to J1 shown in fig. 3.
The connector J1 can be used for connecting the enameled wire sensor and the detection circuit, and is required to be waterproof and firm. The connector and the processing circuit can be connected through a protection circuit 32, and interference signals can not be connected to the processing circuit. The number of the connectors J1 may correspond to the number of the switching circuits.
The connector J1 can be formed using a robust material having water resistance. With connector J1, switching circuit 31 may be electrically connected between connector J1 and processing circuit 40.
As shown in fig. 3, the connector J1 may have four pairs of connection terminals, wherein two pairs of connection terminals are connected between the sensor 33 and the switching circuit 31, and further, two pairs of connection terminals are connected to the ground line PGND. Although the connector J1 is shown to have four pairs of connection terminals, it is not limited thereto.
Because the size of the variable-pitch bearing is larger, the radius of a circle formed by an enameled wire reaches up to several meters, and the enameled wire is a closed ring. The variable pitch bearing is installed in the air, the electromagnetic environment is very bad, and the induced lightning stroke, the switch surge and other intrusions are often received. Corresponding voltage signals are inevitably induced on the enameled wires, and if the enameled wires are directly connected to a processing circuit, the induced interference signals can burn out the circuit. The enameled wire enters a filter protection circuit after passing through the connector, and the circuit can effectively filter destructive voltage signals such as interference, induced voltage and the like.
As an example, the detection circuit 30 may also include a filter protection circuit 34, for example, the filter protection circuit 34 may include a first filter protection circuit, a second filter protection circuit, and a third filter protection circuit. Each filter protection circuit may have the same configuration.
Each filter protection circuit may include a first protection circuit 321 configured to shield a surge signal, a second protection circuit 322 configured to shield an overvoltage, a third protection circuit 323 configured for overcurrent protection, and a first filter circuit 324 configured to filter an interference signal.
As shown in fig. 3, as an example, the first protection circuit 321 may include a gas discharge tube D1, the gas discharge tube D1 being connected between the ground line PGND and the respective sides of the two pairs of normally open contacts of the relay K1. When there is a large disturbance or surge, the gas discharge tube D1 may bleed most of the disturbance signal to the ground line PGND.
The second protection circuit 322 may include a transient suppression diode (TVS), which may include diodes D6, D7, and U3. When there is an overvoltage, the diodes D6, D7, U3 conduct to discharge the interference signal to the ground line PGND.
The third protection circuit 323 may include fuses U1 and U2 for overcurrent protection. When overcurrent flows, the fuses U1 and U2 are disconnected to prevent overcurrent from flowing. The filter circuit 324 may be a pi-type filter formed by capacitors C1 and C2 and a transformer T1, but is not limited to such a configuration as long as it can effectively filter an interference signal whose speed changes rapidly.
Although the filter protection circuit is shown in the drawings to include four sub-circuits, the number of sub-circuits may be increased or decreased according to actual needs. Further, the constituent components and circuit arrangement of the first to third protection circuits 321 to 323 and the first filter circuit 324 are not limited thereto, and they may be changed according to design as long as they can realize the respective functions.
The filter protection circuit 34 may also include a multiplier that may multiply the output signal of the first filter circuit with the excitation signal to filter the noise signal. A multiplier can be arranged on each monitoring loop.
For example, let s (t) be Vscos(ωmt + θ) is a weak small signal to be measured, and as an example, due to crosstalk, a signal with the same frequency can be induced on 3 enameled wires near the enameled wire with the excitation signal, according to the embodiment of the present disclosure, there may be 3 signals to be measured, n (t) is a noise signal (the noise signal may be generated by lightning strike, surge, etc. on the line), and the reference signal may be r (t) ═ Vrcos(ωmt), (which may be generated by the signal generator 20, applied to one of the 4 enameled wires) and a noisy input signal x (t) (s (t)) + n (t)). The cross-correlation function of the input signal with the reference signal is:
in the formula (1), Rsr(t) is the cross-correlation function of the signal to be measured and the reference signal; rnr(t) is the cross-correlation function of the noise and reference signals. R since the noise is uncorrelated with the reference signalnr(t) is 0, thus obtaining Rxr(t)＝Rsr(t), i.e. the cross-correlation function of the input signal and the reference signal is only the cross-correlation function of the signal to be measured and the reference signal, thereby filtering out noise interference.
It can be seen that the original frequency is ω after correlation processingmTo frequencies of 0 and 2 omegamWhere the shape after spectral migration does not change to an amplitude of
The signal after passing through the multiplier passes through a low-pass filter, only the difference frequency component is output, and the output signal is as follows:
the principle of detecting the breakage of the enameled wire is shown as follows, the detection of the 1mm crack is taken as an example for explanation, and the rest is similar:
as can be seen from the above calculation formula, the analog value detected by an analog-to-digital converter (described below) in the processing circuit when the enameled wire is not disconnected is:
reference signal r (t) is Vrcos(ωmt) amplitude VrV when the enameled wire is broken or is about to breaksThe size of the liquid crystal will gradually become smaller,when V issWhen the initial value of the tensile strength becomes 80%, the enameled wire is determined to start to be drawn and break, and when V is reachedsWhen the value is changed to 30 percent of the original value, the enameled wire is judged to be completely broken, and the detection system can output an alarm to complete the whole detection process.
When r (t) is equal to Vrcos(ωmWhen t) is 0, namely the enameled wires of the reference signal line are also broken, the voltage signals induced by crosstalk on the other 3 enameled wires completely disappear, only noise remains, the analog values detected by the three enameled wires are basically equal, and the unit needs to be shut down under the very dangerous condition. In addition to the inductive mode, the signal generated by the signal generator may be applied directly to the first sensor, the second sensor, and the third sensor.
The processing circuitry 40 may comprise an analog-to-digital converter 401 and a processor 402, the analog-to-digital converter 401 may perform an analog-to-digital conversion on the respective detection signals (e.g. the first detection signal and the second detection signal) to obtain digital signals, and the processor 402 may generate an output signal indicative of the state of the pitch bearing from the digital signals.
The crack monitoring system may further comprise other auxiliary components, for example, the crack monitoring system may further comprise a wireless transmitting module, a wireless receiving module, etc.
The processing circuitry 40 may control the second switching circuit to open in response to the first sensor not being in an open state during the monitoring, and the processing circuitry 40 may also control both the second switching circuit and the third switching circuit to open in response to the first sensor not being in an open state during the monitoring.
The processing circuitry 40 may control the second switching circuit to be on during the monitoring in response to the first sensor being in an off state, and the processing circuitry 40 may also control the third switching circuit to be on during the monitoring in response to the second sensor being in an off state.
The processing circuit 40 may have a self-checking function for manual checking and initial installation self-checking. The processing circuit 40 may simultaneously turn on the first, second, and third switching circuits to perform self-tests or manual troubleshooting.
FIG. 4 is a schematic diagram illustrating a control approach of a crack monitoring system of a pitch bearing according to an embodiment of the present disclosure.
The on state of the sensor may be detected every 10 minutes, but is not limited thereto, and the interval time may be adjusted as needed. Each large sample includes 5 small samples, and the small sample interval is 1 second (or 5 seconds, 10 seconds, etc., which can be set as needed). The more the number of sampled data, the smoother the data and the lower the probability of false alarms.
In FIG. 4, A0-A4 and B0-B4 are separated by 10 minutes, B0-B4 and C0-C4 are separated by 10 minutes, and C0-C4 and D0-D4 are separated by 10 minutes. Hereinafter, 5 data acquired for the first 10 minutes will be described as C0 to C4, 5 data acquired for the second 10 minutes will be B0 to B4, and 5 data acquired for the third 10 minutes will be described as a B0 to a4, but the present invention is not limited thereto, and for example, 5 data acquired for the first 10 minutes will be D0 to D4, and 5 data acquired for the second 10 minutes will be described as C0 to C4.
Similarly, the processor 402 may store the results of the states of 5 data of a 0-a 4, which are equal to or greater than 3 coincidences, in the R2 position of the FIFO register, thereby realizing the storage of the first group of data in the FIFO register. While the FIFO register holds only the latest 3 data and is a rolling store.
That is, the data that was first stored in the FIFO register is deleted, e.g., R0, and the latest acquisition result is stored, e.g., R3, each 10 minutes of sampling time.
Specifically, the processor 40 may store the state results of 5 data collected in the fourth 10 minutes into the FIFO register, where the first group of data R2, R1, and R0 of the FIFO register is replaced with the second group of data R3, R2, and R1, the second group of data R3, R2, and R1 of the FIFO register is replaced with the third group of data R4, R3, and R2 after the fifth 10 minute sampling, the third group of data R4, R3, and R2 of the FIFO register is replaced with the fourth group of data R5, R4, and R3 … … after the sixth 10 minute sampling, and so on.
Specifically, after storing the first set of data R2, R1, and R0 in the FIFO register, 2 consistent state results (such as "1", or "0") may be taken; after the fourth 10 minute sample, 2 consistent state results may be taken; after the fifth 10 minute sample, 2 consistent state results were taken; after the sixth 10 minute sampling, 2 consistent state results were obtained, and further, whether cracks occurred or not was judged. The state of progress of the crack can be further judged.
In the case that the crack monitoring system comprises a wireless transmitting module, a wireless receiving module and the like. The processor 402 may control the wireless transmitter module to transmit the state results (e.g., "1", or "0") of 5 data in C0-C4 that are equal to or greater than 3 identical states to the wireless receiver module, the wireless receiver module stores the received state results in the R0 position of a first-in-first-out (FIFO) register, and so on, the processor 402 controls the wireless transmitter module to transmit the state results of 5 data in B0-B4 that are equal to or greater than 3 identical states to the wireless receiver module, and the wireless receiver module stores the received state results in the R1 position of the FIFO register. Similarly, the processor 402 controls the wireless transmitting module to send the state results of 5 data in the data groups a 0-a 4, wherein the state results are equal to or more than 3 data, to the wireless receiving module, and the wireless receiving module stores the received state results in the R2 position of the FIFO register, thereby realizing the storage of the first group of data in the FIFO register. While the FIFO register holds only the latest 3 data and is a rolling store. That is, the data that was first stored in the FIFO register is deleted, e.g., R0, and the latest acquisition result is stored, e.g., R3, each 10 minutes of sampling time. Specifically, the processor 402 controls the wireless transmission module to send the state result obtained by taking 3 or more consistent states from the 5 data collected in the fourth 10 minutes to the wireless reception module, and the wireless reception module stores the received state result in the FIFO register, at this time, the first group of data R2, R1 and R0 of the FIFO register is replaced by the second group of data R3, R2 and R1, after the fifth 10 minute sampling, the second group of data R3, R2 and R1 of the FIFO register is replaced by the third group of data R4, R3 and R2, after the sixth 10 minute sampling, the third group of data R4, R3 and R2 of the FIFO register is replaced by the fourth group of data R5, R4 and R3 … …, and so on. The wireless receive module sends 2 coherent states out of 3 data in the FIFO register to the processor 402 every 10 minutes. Specifically, after storing the first set of data R2, R1, and R0 in the FIFO register, the wireless reception module sends 2 consistent state results (such as "1", or "0") out of the first set of data R2, R1, and R0 to the processor 402; after the fourth 10 minute sample, the wireless receive module sends 2 consistent state results from the second set of data R3, R2, and R1 to the processor 402; after the fifth 10 minute sample, the wireless receive module sends the 2 consistent state results from the third set of data R4, R3, and R2 to the processor 402; after the sixth 10-minute sampling, the wireless receiving module sends 2 consistent state results in the fourth group of data R5, R4 and R3 to the processor 402 … …, and so on, to determine whether a crack is generated, and further determine the development process of the crack.
When the processor 402 is implemented by a single chip microcomputer, a first input/output (I/O) port of the single chip microcomputer is used for applying a high level to the electric control device 312 of the switching circuit 31 to turn on the switching circuit 31, then a second input/output (I/O) port of the single chip microcomputer is used for applying a high level to the sensor, and then a third I/O port of the single chip microcomputer is used for detecting whether the high level is received, if the high level is received, the pitch bearing is good, and if the high level is not received, the bearing crack is detected.
In addition, when a low level is applied to the electric control device 312 of the switching circuit 31 using the second I/O port driving circuit of the one-chip microcomputer, the switching circuit 31 is disconnected.
That is, the electric control devices of the switch circuit 31 can be respectively controlled through the I/O ports of the single chip, so that the first switch circuit, the second switch circuit and the third switch circuit in the switch circuit are turned on or off.
As described earlier, the processing circuit 40 is in a low state during the absence of the turn-on detection. In addition, the minimum requirement that the protection circuit 32 achieves is the differential mode ± 1 kV. The switch circuit 31 becomes a closed state only before the start of the detection process, and when the detection process is completed, the switch circuit 31 is disconnected to prevent the processing circuit from being broken by external disturbance.
That is, the processing circuit may control the first switching circuit and the second switching circuit to be turned off after the monitoring is completed. When the switching circuit includes a third switching circuit, the processing circuit may control the first switching circuit, the second switching circuit, and the third switching circuit to turn off after the monitoring is completed.
According to the embodiment of the disclosure, the wireless receiving module can be placed in an engine room, the result obtained by the enameled wire sensor can be transmitted to the processing circuit, and the wireless receiving module continuously receives the bearing cracking signal for multiple times and then gives an alarm to a system.
The wireless receiving module can be provided with a communication state indicator light, an enameled wire on-off state indicator light and a battery electric quantity state indicator light, and is realized by using 9 red-green double-color light-emitting diodes, a light guide column is used for guiding light to the shell, the red indication is abnormal, and the green indication is normal.
And the maintenance personnel judge the problem points according to the states of the indicating lamps. Once alerted, maintenance personnel must go to the site in a timely manner for disposal.
FIG. 5 is a flow chart illustrating a crack monitoring method of a pitch bearing according to an embodiment of the present disclosure.
The crack monitoring method for the pitch bearing according to the embodiment of the disclosure may include step S510, step S520 and step S530.
In step S510, an excitation signal is applied to the first sensor and the second sensor. As mentioned above, the first and second sensors are provided on the same outer circumferential surface of the pitch bearing, and the first and second sensors may change to an off-state in response to the occurrence of different degrees of cracks on the outer circumferential surface of the pitch bearing.
In step S520, the first and second detection signals output by the first and second sensors may be detected. Taking the enameled wire sensor as an example, each set of enameled wires may include at least three enameled wires, two of the enameled wires correspond to the first sensor and the second sensor, and the third enameled wire may be used to apply an excitation signal.
As an example, when a third sensor is included, the third sensor may also detect a third degree of cracking and output a third detection signal. That is, the enamel wire sensor may include four enamel wires.
The first sensor may detect a first degree of cracking (e.g., 1mm cracking), the second sensor may detect a second degree of cracking (e.g., 5mm cracking), and the third sensor may detect a third degree of cracking (e.g., 8mm cracking).
In step S530, the state of the pitch bearing is determined according to the first detection signal and the second detection signal.
As an example, the state of the pitch bearing may also be determined from the first, second and third detection signals.
In one example, when the amplitude of the first detection signal is smaller than a predetermined threshold value and the amplitude of the second detection signal is larger than the predetermined threshold value, it can be determined that the first sensor is broken, and the second sensor is not broken, which indicates that a crack of about 1mm occurs in the pitch bearing, and then an alarm signal can be generated; when the amplitude of the second detection signal is smaller than a preset threshold value and the amplitude of the third detection signal is larger than the preset threshold value, the first sensor and the second sensor can be determined to be broken, the third sensor is not broken, the fact that cracks of about 5mm occur in the variable pitch bearing is indicated, and then serious early warning signals can be generated; when the amplitude of the third detection signal is less than the predetermined threshold, it may be determined that the third sensor is broken, at which time a shutdown for maintenance is required.
It should be noted that whether the amplitude of the detection signal exceeds the threshold value or not may be determined several times in succession, and each time the threshold value is exceeded may be counted (e.g., by a temporarily stored flag), and after determining that the count value is equal to a predetermined value (e.g., 3, 4, or 5), the warning signal, the serious warning signal, or the shutdown signal may be generated.
It should be understood that the various units or modules in the crack monitoring system according to exemplary embodiments of the present disclosure may be implemented as hardware components and/or software components. Those skilled in the art may implement the various units, for example, using Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), software algorithms, etc., depending on the processing performed by the defined various units.
According to various embodiments of the present disclosure, an apparatus (e.g., a module or their functions) or a method may be implemented by a program or instructions stored in a computer-readable storage medium. In the case where the instruction is executed by a processor, the processor may perform a function corresponding to the instruction or perform a method corresponding to the instruction. At least a portion of the modules may be implemented (e.g., executed) by a processor. At least a portion of the programming modules may include modules, programs, routines, instruction sets, and procedures for performing at least one function. In one example, the instructions or software include machine code that is directly executed by one or more processors or computers (such as machine code produced by a compiler). In another example, the instructions or software comprise higher level code that is executed by one or more processors or computers using an interpreter. The instructions or software may be written in any programming language based on the block diagrams and flow diagrams illustrated in the figures and the corresponding description in the specification.
A module or programming module of the present disclosure may include at least one of the foregoing components with some components omitted or other components added. Operations of the modules, programming modules, or other components may be performed sequentially, in parallel, in a loop, or heuristically. Further, some operations may be performed in a different order, may be omitted, or expanded with other operations.
The respective operations of the above steps may be written as software programs or instructions, and thus, the crack monitoring method according to the exemplary embodiment of the present disclosure may be implemented via software, and the computer-readable storage medium of the embodiment of the present disclosure may store a computer program that, when executed by a processor, implements the crack monitoring method as described in the above exemplary embodiment.
Examples of the computer readable storage medium may include magnetic media such as a floppy disk and a magnetic tape, optical media (including a Compact Disc (CD) ROM and a DVD ROM), magneto-optical media such as a floppy disk, hardware devices such as a ROM, a RAM, and a flash memory, which are designed to store and execute program commands. The program command includes a language code executable by a computer using an interpreter and a machine language code generated by a compiler. The hardware devices described above may be implemented by one or more software modules for performing the operations of the various embodiments of the present disclosure.
Therefore, the crack monitoring system of the embodiment of the disclosure can dynamically monitor whether the variable pitch bearing has cracks on line, and can realize filtering, thereby reducing the false alarm probability.
As set forth above, the crack monitoring system according to the above exemplary embodiments may prevent external interference and reduce surge and/or noise interference, thereby reducing a false alarm rate and improving monitoring reliability.
According to the crack monitoring system disclosed by the embodiment of the disclosure, the crack development state of the variable pitch bearing can be dynamically monitored on line, and the crack monitoring system has an automatic monitoring function and improves the efficiency.
Furthermore, the crack monitoring system according to the above exemplary embodiments may be part of a wind park.
According to the crack monitoring system and the crack monitoring method disclosed by the embodiment of the disclosure, early warning can be timely and hierarchically carried out after cracking: warning, severe warning, and shutdown.
According to the crack monitoring system and the crack monitoring method disclosed by the embodiment of the disclosure, the enameled wire does not need to be frequently replaced.
According to the crack monitoring system and the crack monitoring method, the false alarm rate can be reduced.
Although a few exemplary embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments, for example, in which features of different embodiments may be combined, without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. Embodiments obtained by combining technical features in different embodiments should be considered as part of the present disclosure.
Claims (12)
1. A crack monitoring system of a pitch bearing, the crack monitoring system comprising:
a signal generator configured to generate an excitation signal;
a detection circuit including a first sensor and a second sensor that receive the excitation signal, and outputting a first detection signal and a second detection signal according to an on-off state of the first sensor and the second sensor, wherein the first sensor and the second sensor are provided on an outer circumferential surface of the same pitch bearing, the first sensor itself changes to an off state in response to occurrence of a first degree of crack on the outer circumferential surface of the pitch bearing, and the second sensor itself changes to an off state in response to occurrence of a second degree of crack on the outer circumferential surface of the pitch bearing, wherein a gap of the second degree of crack is larger than a gap of the first degree of crack;
processing circuitry to generate an output signal indicative of a state of the pitch bearing based on the first and second detection signals.
2. Crack monitoring system of a pitch bearing according to claim 1,
the processing circuitry is responsive to the first sensor being in an off state and the second sensor not being in an off state to generate a first output signal indicative of the pitch bearing developing a crack;
the processing circuitry is responsive to the second sensor being in an off state to generate a second output signal indicating that the pitch bearing requires shutdown maintenance.
3. The crack monitoring system of a pitch bearing of claim 2, wherein the processing circuitry comprises:
an analog-to-digital converter that performs analog-to-digital conversion on the first detection signal and the second detection signal to obtain a digital signal;
a processor that generates an output signal indicative of a state of the pitch bearing from the digital signal.
4. The crack monitoring system of a pitch bearing of claim 1, wherein the detection circuit further comprises:
a first switching circuit electrically connected between the first sensor and the processing circuit;
a second switching circuit electrically connected between the second sensor and the processing circuit and turned on in response to the first sensor being in an off state during monitoring.
5. Crack monitoring system of a pitch bearing according to claim 4,
the processing circuit controls the second switching circuit to open in response to the first sensor not being in an open state during monitoring.
6. The crack monitoring system of a pitch bearing of claim 5, wherein the processing circuitry controls the signal generator to generate the excitation signals applied to the first and second sensors at a predetermined period;
the processing circuit controls the first switching circuit and the second switching circuit to be turned off after the monitoring is completed.
7. The crack monitoring system of a pitch bearing of claim 1, wherein the detection circuit further comprises a filter protection circuit electrically connected to the first sensor and the second sensor, the filter protection circuit comprising:
a first protection circuit configured to shield a surge signal;
a second protection circuit configured to shield an overvoltage;
a third protection circuit configured for overcurrent protection; and
a first filtering circuit configured to filter the interference signal.
8. The crack monitoring system of a pitch bearing of claim 7, wherein the filter protection circuit further comprises a multiplier that multiplies the output signal of the first filter circuit with the excitation signal to filter a noise signal.
9. The crack monitoring system of a pitch bearing according to any of claims 1-8, wherein the first sensor and the second sensor are realized by at least one of copper foil, aluminum foil and tin foil.
10. The crack monitoring system of a pitch bearing according to any of claims 1 to 8, wherein the detection circuit further comprises a third sensor receiving the excitation signal and outputting a third detection signal according to an on-off state of the third sensor, wherein the first sensor, the second sensor and the third sensor are arranged on the outer circumferential surface of the same pitch bearing, the third sensor itself changes to an off state in response to the occurrence of a third degree of crack on the outer circumferential surface of the pitch bearing, the third degree of crack having a larger gap than the second degree of crack;
the processing circuitry generates an output signal indicative of a state of the pitch bearing based on the first, second and third detection signals.
11. A wind park according to any of claims 1-10, characterized by a crack monitoring system of a pitch bearing.
12. A crack monitoring method for a variable-pitch bearing is characterized by comprising the following steps:
applying excitation signals to a first sensor and a second sensor, wherein the first sensor and the second sensor are disposed on a same outer circumferential surface of a pitch bearing, the first sensor itself changing to an open state in response to the occurrence of a first degree of cracking on the outer circumferential surface of the pitch bearing, the second sensor itself changing to an open state in response to the occurrence of a second degree of cracking on the outer circumferential surface of the pitch bearing, wherein the second degree of cracking has a greater gap than the first degree of cracking;
detecting first and second detection signals output by the first and second sensors;
and determining the state of the pitch bearing according to the first detection signal and the second detection signal.
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| WO2021060645A1 (en) * | 2019-09-24 | 2021-04-01 | (주)엘 테크 | Crack sensor and low power-driven crack detection system using same |
| CN213870132U (en) * | 2020-12-23 | 2021-08-03 | 北京金风科创风电设备有限公司 | Crack monitoring system for rotating component and wind generating set |
| CN113474643A (en) * | 2019-02-27 | 2021-10-01 | 三菱重工业株式会社 | Crack sensor system |
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| JP2014077253A (en) * | 2012-10-09 | 2014-05-01 | Highway Technology Research Center | Device and method for monitoring structure crack, and disconnection gauge |
| CN207571112U (en) * | 2017-12-25 | 2018-07-03 | 新疆金风科技股份有限公司 | For the crack detection device and wind power generating set of pivoting support bearing |
| CN113474643A (en) * | 2019-02-27 | 2021-10-01 | 三菱重工业株式会社 | Crack sensor system |
| WO2021060645A1 (en) * | 2019-09-24 | 2021-04-01 | (주)엘 테크 | Crack sensor and low power-driven crack detection system using same |
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