A device and method for generating a key phase reference signal for blade vibration measurement

Abstract

The invention discloses a blade vibration measurement key phase reference signal generating device and method. The signal generating device comprises a controller and a rotation speed measurement sensor, a drive and conditioning module, a level conversion module, a phase-locked frequency multiplication unit and a fractional frequency division unit which are connected in sequence. The phase-locked frequency multiplication unit comprises a phase detector, a loop filter, a voltage-controlled oscillator and a frequency divider which are connected in sequence end to end. The controller is connected with the level conversion module, the fractional frequency division unit and the frequency divider. The invention utilizes the advantages of high synthetic frequency stability, low phase noise level and short frequency establishment time of the phase-locked technology. Through phase comparison of the phase detector and signal feedback of the frequency divider, the phase error between the original test rotation speed signal and the generated key phase reference signal can be suppressed, so as to realize the extraction of the blade vibration measurement key phase reference with high time positioning accuracy.

Description

Technical Field

[0001] The present invention belongs to the field of non-contact measurement of vibration parameters of rotating blades. Specifically, the present invention relates to a method for generating a key phase reference signal for blade vibration measurement, and in particular to a device and method for generating a key phase reference signal for blade vibration measurement that uses a phase-locked loop to realize multiple / division of rotating speed for rotating machinery testing. Background Art

[0002] As the core working parts of large rotating machinery such as aircraft engines, gas turbines, steam turbines, and flue gas turbines, the health status of blades directly affects the working efficiency and operation safety of rotating machinery. High-speed rotating blades are very prone to fatigue damage under the action of various loads such as temperature and aerodynamics. Especially when the blades resonate, the vibration amplitude is most significant. The high-cycle fatigue damage caused by them is the main failure form of blades, which will cause cracks, fractures and other failures in the blades, causing direct economic losses and even safety accidents. The online measurement of vibration parameters of moving blades can provide important data support for fault diagnosis and predictive maintenance of rotating machinery, and is the key to ensuring the safe operation of equipment. The blade tip timing method with the characteristics of non-contact, low intervention, online, and high precision is currently the standard technology for engineering testing of vibration parameters of moving blades of large rotating machinery. Traditionally, this technology requires the use of a speed synchronization sensor. When the impeller rotates one circle, a pulse signal is obtained, and its frequency is equal to the speed frequency; this pulse signal is used as a key phase reference signal to provide a time reference for blade vibration measurement. However, the speed synchronization sensor is installed near the shaft, which is different from the axial position of the blade disk. The torsion and bending of the shaft will change the accuracy of the time reference, thereby introducing a large blade tip timing error. In addition, in the narrow space inside the large rotating machinery, the speed synchronization sensor is difficult to install, easy to fall off, and easily affected by oil pollution and then fail, which reduces the reliability and safety of the engineering test of blade vibration parameters. Therefore, it is of great engineering significance to study the method of generating the key phase reference signal for blade vibration measurement without the speed synchronization sensor.

[0003] Rotor speed is another important state parameter that affects the working efficiency and operation safety of rotating machinery. Speed ​​control is the specific embodiment of rotating machinery state control, and speed measurement is the premise of speed control. Rotating machinery often uses a gear system transmission method such as a driving wheel and a driven wheel to achieve the normal operation of the rotor system. The speed measurement sensor is installed on the shaft of the driving wheel. The test speed signal is obtained by engraving a groove on the shaft facing the sensor or installing a toothed tone wheel. However, due to the influence of the transmission relationship, there is a difference in frequency between the test speed signal and the key phase reference signal, and the ratio is a decimal; based on the test speed signal, it is a technical problem to generate a blade vibration measurement key phase reference signal in real time online to ensure the time positioning accuracy. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a device and method for generating a key phase reference signal for blade vibration measurement. The present invention utilizes the test speed signal of the active wheel shaft, adopts a frequency synthesis technology based on a phase-locked loop, and realizes the generation of a key phase reference signal for blade vibration measurement by multiplying / dividing the signal frequency, thereby providing a time reference extraction scheme for the vibration measurement of the moving blades of a rotating machinery without a speed synchronization sensor.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A blade vibration measurement key phase reference signal generating device based on phase-locked technology is applied to the shaft transmission structure of a rotating machine, the shaft transmission structure comprises a driving wheel shaft with a driving wheel installed, a driven wheel shaft with a driven wheel installed, the driving wheel and the driven wheel are meshed, and a rotating blade is also installed on the driven wheel shaft; the driving wheel shaft is provided with a groove, a barcode or a tone wheel; the signal generating device comprises a controller and a rotation speed measurement sensor, a driving and conditioning module, a level conversion module, a phase-locked frequency multiplication unit and a fractional frequency division unit connected in sequence, the phase-locked frequency multiplication unit comprises a phase detector, a loop filter, a voltage-controlled oscillator and a frequency divider connected in sequence; the controller is connected to the driving and conditioning module, the fractional frequency division unit and the frequency divider;

[0007] The speed measuring sensor is installed at the driving wheel shaft, and the probe of the speed measuring sensor is facing the grooves, barcodes or sound wheel on the driving wheel shaft; under the drive and conditioning module, the speed measuring sensor outputs the same number of test speed signals as the number of grooves, the number of barcodes or the number of teeth of the sound wheel when the shaft rotates one circle as the engine speed changes;

[0008] The driving and conditioning module drives the speed measurement sensor to work under the control of the controller, and receives the test speed signal generated by the speed measurement sensor, which is amplified by the amplifier circuit and filtered by the filter circuit in the driving and conditioning module, and then generates a pre-processed voltage signal to be transmitted to the level conversion module;

[0009] The level conversion module receives the pre-processed voltage signal, performs level conversion by threshold level cutting, converts the pre-processed voltage signal from an analog signal to a digital signal, generates a pulsed digital voltage signal and transmits it to the phase-locked frequency multiplication unit;

[0010] In the phase-locked frequency multiplication unit, the phase detector generates a pulse-shaped error voltage signal related to the phase difference by comparing the phase difference between the digital voltage signal output by the level conversion module and the feedback signal output by the frequency divider; the loop filter adopts a low-pass filter type to process the error voltage signal into a DC voltage signal; the voltage-controlled oscillator generates a pulse-shaped phase-locked frequency multiplication signal under the control of the DC voltage signal and transmits it to the fractional frequency division unit and the frequency divider at the same time; the frequency divider divides the phase-locked frequency multiplication signal under the control of the controller to generate a feedback signal to be transmitted to the phase detector;

[0011] The fractional frequency division unit divides the phase-locked frequency multiplication signal under the control of the controller to generate a pulse-shaped blade vibration measurement key phase reference signal.

[0012] Furthermore, the rotation speed measurement sensor adopts a magnetoelectric sensor, a Hall sensor or a photoelectric sensor, and the generated pulse signal is a voltage signal or a current signal.

[0013] Furthermore, the phase-locked frequency multiplication unit adopts an analog phase-locked loop or a digital phase-locked loop, and the phase detector adopts a multiplier or a sequential circuit type.

[0014] Furthermore, the fractional frequency division unit uses one or more frequency dividers to implement the frequency division function.

[0015] A method for obtaining a blade vibration measurement key phase reference signal based on the signal generating device comprises:

[0016] S1. After starting the signal generating device, the driving and conditioning module drives the speed measuring sensor to work under the control of the controller. The sensor generates a test speed signal with a repetition frequency of f. s , and f s =M·f r , where M is the number of grooves, barcodes or teeth of the tone wheel on the driving wheel shaft facing the speed measurement sensor probe, and f r is the speed of the driving wheel shaft;

[0017] S2, the test speed signal is amplified and filtered by the drive and conditioning module and converted by the level conversion module to generate a pulse digital voltage signal. The digital voltage signal is frequency multiplied in the phase-locked frequency multiplication unit to generate a phase-locked frequency multiplication signal. The repetition frequency of the phase-locked frequency multiplication signal is f p , and f p =m1·M·f r , where m1 is the number of teeth on the driving wheel;

[0018] S3, the phase-locked frequency multiplication signal is frequency-divided in the fractional frequency division unit to generate a blade vibration measurement key phase reference signal. The repetition frequency of the blade vibration measurement key phase reference signal is f o , and fo =m1 / m2·f r , where m2 is the number of teeth on the driven gear.

[0019] Furthermore, when the greatest common divisor of m1 and m2·M is N, the multiplication number of the phase-locked frequency multiplication unit in step S2 is m1 / N, which is implemented by the controller configuring the frequency divider; the division number of the fractional frequency division unit in step S3 is m2·M / N, which is implemented by the controller configuring the fractional frequency division unit.

[0020] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0021] 1. To overcome the shortcomings of the traditional blade vibration measurement key phase reference extraction method that is difficult to meet the accuracy, reliability and safety of engineering tests, and to avoid the problems of the speed synchronization sensor being difficult to install, easy to fall off, susceptible to failure due to oil pollution, and the time reference accuracy being susceptible to the torsion and bending of the shaft. The key phase reference extraction scheme without the speed synchronization sensor provided by the present invention utilizes the test speed signal of the active wheel shaft, and does not require the installation and debugging of the speed synchronization sensor, so as to realize reliable and safe key phase reference extraction in an engineering environment.

[0022] 2. The present invention utilizes the shaft speed signal that is usually monitored in large-scale rotating machinery engineering tests as the basis for extracting the key phase reference, and provides a new device and method for extracting the key phase reference under the condition of no speed synchronization sensor. This method does not rely on the blade vibration measurement pulse signal based on blade tip timing, thereby avoiding the problem of key phase error introduced by blade vibration when directly extracting the key phase reference from the blade vibration measurement pulse signal, thereby ensuring the key phase signal extraction accuracy of the device and method in the blade resonance speed region.

[0023] 3. The multiplication / division of the test speed signal frequency is achieved by utilizing the phase-locked technology, which is successively achieved through the multiplication of the phase-locked frequency multiplication unit and the division of the decimal frequency division unit; the blade vibration measurement key phase reference signal generating device and method based on the phase-locked technology provided by the present invention utilizes the advantages of the phase-locked technology in terms of high synthetic frequency stability, low phase noise level, and short frequency establishment time. Through the phase comparison of the phase detector and the signal feedback of the divider, the phase error between the original test speed signal and the generated key phase reference signal can be suppressed, thereby realizing the extraction of the blade vibration measurement key phase reference with high time positioning accuracy.

[0024] 4. The problem of decimal multiples / frequency divisions in the process of extracting the key phase reference of blade vibration measurement is solved. According to the number of grooves on the rotating shaft facing the sensor probe, the number of barcodes or the number of teeth of the tone wheel, the number of teeth of the driving wheel and the number of teeth of the driven wheel, the greatest common divisor of the decimal multiples / frequency divisions is obtained, and the multiples of the phase-locked frequency multiplication unit and the frequency divisions of the decimal frequency division unit are reasonably set, which narrows the signal frequency range that needs to be processed by the frequency multiplication and frequency division links, reduces the difficulty of decimal multiples / frequency divisions, and realizes flexible and accurate frequency multiplication and division. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a blade vibration measurement key phase reference signal generating device based on phase-locked technology of the present invention.

[0026] Figure 2 It is a schematic diagram of the shaft transmission structure and the installation position of the speed measurement sensor of a large rotating machinery.

[0027] Figure numerals: 1-speed measurement sensor, 2-drive and conditioning module, 3-level conversion module, 4-phase-locked frequency multiplication unit, 5-decimal frequency division unit, 6-controller, 7-phase detector, 8-loop filter, 9-voltage-controlled oscillator, 10-divider, 11-engine casing, 12-blade tip timing sensor, 13-rotating blades, 14-driven wheel, 15-driven wheel shaft, 16-driving wheel, 17-driving wheel shaft, 18-shaft groove. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Example 1

[0030] This embodiment provides a blade vibration measurement key phase reference signal generating device based on phase-locked technology, which is applied to the shaft transmission structure of a rotating machine. Figure 2 The shaft transmission structure is installed in the engine casing 11, and the shaft transmission structure includes a driving wheel shaft 17 on which a driving wheel 16 is installed, and a driven wheel shaft 15 on which a driven wheel 14 is installed, the driving wheel 16 and the driven wheel 14 are meshed, and a rotating blade 13 is also installed on the driven wheel shaft 15, and a blade tip timing sensor 12 is installed on the engine casing 11; the driving wheel shaft is provided with a groove, a barcode or a tone wheel, wherein the groove and the barcode can be set on the driving wheel shaft by engraving, and the tone wheel is installed on the driving wheel shaft by a fixed connection.

[0031] See Figure 1As shown, the signal generating device includes a controller 6 and a rotation speed measuring sensor 1, a driving and conditioning module 2, a level conversion module 3, a phase-locked frequency multiplication unit 4 and a fractional frequency division unit 5 which are connected in sequence, and the phase-locked frequency multiplication unit 4 includes a phase detector 7, a loop filter 8, a voltage-controlled oscillator 9 and a frequency divider 10 which are connected in sequence from beginning to end; the controller 6 is connected to the driving and conditioning module 2, the fractional frequency division unit 5 and the frequency divider 10;

[0032] The speed measurement sensor 1 is installed on the driving wheel shaft 17, and its probe is facing the shaft groove 18, the barcode or the installed sound wheel; the speed measurement sensor 1 is driven by the driving and conditioning module 2, and as the engine speed changes, when the shaft rotates one circle, it outputs a test speed signal with the same number as the number of shaft grooves 18, the number of barcodes or the number of teeth of the sound wheel.

[0033] The driving and conditioning module 2 drives the speed measurement sensor 1 to work under the control of the controller 6, and receives the test speed signal generated by the speed measurement sensor 1, which is amplified by the amplifier circuit and filtered by the filter circuit to generate a pre-processed voltage signal and transmitted to the level conversion module 3.

[0034] The level conversion module 3 receives the preprocessed voltage signal, performs level conversion by threshold level cutting, converts the signal from an analog signal to a digital signal, and generates a pulsed digital voltage signal which is transmitted to the phase-locked frequency multiplication unit 4 .

[0035] In the phase-locked frequency multiplication unit 4, the phase detector 7 generates a pulse-shaped error voltage signal related to the phase difference by comparing the phase difference between the digital voltage signal output by the level conversion module 3 and the feedback signal output by the frequency divider 10; the loop filter 8 adopts a low-pass filter type to process the error voltage signal into a DC voltage signal; the voltage-controlled oscillator 9 generates a pulse-shaped phase-locked frequency multiplication signal under the control of the DC voltage signal and transmits it to the fractional frequency division unit 5 and the frequency divider 10 at the same time; the frequency divider 10 divides the phase-locked frequency multiplication signal under the control of the controller to generate a feedback signal to be transmitted to the phase detector 7.

[0036] The fractional frequency division unit 5 divides the phase-locked frequency-multiplied signal under the control of the controller 6 to generate a blade vibration measurement key phase reference signal in the form of a pulse.

[0037] Furthermore, in the above embodiment:

[0038] The speed measurement sensor 1 can be a magnetoelectric sensor, a Hall sensor or a photoelectric sensor. The pulse signal generated is a voltage signal or a current signal, and the pulse signal can be in the form of a unipolar pulse or a bipolar pulse; the level conversion module 3 can use a fixed threshold level cutting method to convert the analog voltage signal into a TTL level digital signal; the phase-locked frequency multiplication unit 4 adopts an analog phase-locked loop or a digital phase-locked loop type, and the phase detector 7 adopts a multiplier or a timing circuit type; the loop filter 8 plays a role in suppressing phase noise and stray noise, and a passive filter or an active filter can be selected; the fractional frequency division unit 5 uses one or more frequency dividers to realize the frequency division function; the controller 6 can select an STM32 series microcontroller.

[0039] Specifically, in combination with the signal generating device provided in the above embodiment, the specific contents of the method for generating a key phase reference signal for blade vibration measurement based on the phase-locked technology are as follows:

[0040] S1. After starting the signal generating device, the driving and conditioning module 2 drives the speed measuring sensor 1 to work under the control of the controller 6. The speed measuring sensor 1 generates a test speed signal with a repetition frequency of f. s , and f s =M·f r , where M is the number of shaft grooves 18, the number of bar codes or the number of teeth of the tone wheel that the sensor probe faces, and f r is the rotation speed of the driving wheel shaft 17;

[0041] S2, the test speed signal is amplified and filtered by the driving and conditioning module 2 and converted by the level conversion module 3 to generate a pulse digital voltage signal. The signal is frequency multiplied in the phase-locked frequency multiplication unit 4 to generate a phase-locked frequency multiplication signal. The repetition frequency of the signal is f p , and f p =m1·M·f r , where m1 is the number of teeth of the driving wheel 16;

[0042] S3, the phase-locked frequency multiplication signal is frequency-divided in the fractional frequency division unit 5 to generate a blade vibration measurement key phase reference signal, and the repetition frequency of the signal is f o , and f o =m1 / m2·f r , where m2 is the number of teeth of the driven wheel 14;

[0043] Specifically, when the greatest common divisor of m1 and m2·M is N, the frequency multiplication number of the phase-locked frequency multiplication unit 4 in step S2 is m1 / N, which is implemented by the controller 6 configuring the frequency divider 10; the frequency division number of the fractional frequency division unit 5 in step S3 is m2·M / N, which is implemented by the controller 6 configuring the fractional frequency division unit 5. For example, when M=36, m1=50, and m2=80, N=10, the controller 6 sets the frequency multiplication number of the phase-locked frequency multiplication unit 4 to m1 / N=5 by configuring the frequency divider 10; the controller 6 sets the frequency division number of the fractional frequency division unit 5 to m2·M / N=288 by configuring the fractional frequency division unit 5.

[0044] The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solution of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the scope of the present invention and the scope of protection of the claims, a person of ordinary skill in the art can also make many forms of specific changes under the guidance of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A blade vibration measurement key phase reference signal generating device based on phase-locked technology, applied to the shaft transmission structure of a rotating machine, the shaft transmission structure comprises a driving wheel shaft with a driving wheel installed, a driven wheel shaft with a driven wheel installed, the driving wheel and the driven wheel are meshed, and a rotating blade is also installed on the driven wheel shaft; characterized in that: The shaft transmission structure is installed in the engine casing, and a blade tip timing sensor is installed on the engine casing; a groove, a barcode or a tone wheel is arranged on the driving wheel shaft; the signal generating device comprises a controller and a rotation speed measuring sensor, a driving and conditioning module, a level conversion module, a phase-locked frequency multiplication unit and a fractional frequency division unit connected in sequence, and the phase-locked frequency multiplication unit comprises a phase detector, a loop filter, a voltage-controlled oscillator and a frequency divider connected in sequence from beginning to end; the controller is connected to the driving and conditioning module, the fractional frequency division unit and the frequency divider; The speed measuring sensor is installed at the driving wheel shaft, and the probe of the speed measuring sensor is facing the grooves, barcodes or sound wheel on the driving wheel shaft; under the drive and conditioning module, the speed measuring sensor outputs the same number of test speed signals as the number of grooves, barcodes or teeth of the sound wheel when the shaft rotates one circle as the engine speed changes; The driving and conditioning module drives the speed measurement sensor to work under the control of the controller, and receives the test speed signal generated by the speed measurement sensor, which is amplified by the amplifier circuit and filtered by the filter circuit in the driving and conditioning module, and then generates a pre-processed voltage signal to be transmitted to the level conversion module; The level conversion module receives the pre-processed voltage signal, performs level conversion by threshold level cutting, converts the pre-processed voltage signal from an analog signal to a digital signal, generates a pulsed digital voltage signal and transmits it to the phase-locked frequency multiplication unit; In the phase-locked frequency multiplication unit, the phase detector generates a pulse-shaped error voltage signal related to the phase difference by comparing the phase difference between the digital voltage signal output by the level conversion module and the feedback signal output by the frequency divider; the loop filter adopts a low-pass filter type to process the error voltage signal into a DC voltage signal; the voltage-controlled oscillator generates a pulse-shaped phase-locked frequency multiplication signal under the control of the DC voltage signal and transmits it to the fractional frequency division unit and the frequency divider at the same time; the frequency divider divides the phase-locked frequency multiplication signal under the control of the controller to generate a feedback signal to be transmitted to the phase detector; The fractional frequency division unit divides the phase-locked frequency multiplication signal under the control of the controller to generate a pulse-shaped blade vibration measurement key phase reference signal.

2. According to claim 1, a blade vibration measurement key phase reference signal generating device based on phase-locked technology is characterized in that: The rotation speed measurement sensor adopts a magnetoelectric sensor, a Hall sensor or a photoelectric sensor, and the pulse signal generated is a voltage signal or a current signal.

3. According to claim 1, a blade vibration measurement key phase reference signal generating device based on phase-locked technology is characterized in that: The phase-locked frequency multiplication unit adopts an analog phase-locked loop or a digital phase-locked loop, and the phase detector adopts a multiplier or a sequential circuit type.

4. According to claim 1, a blade vibration measurement key phase reference signal generating device based on phase-locked technology is characterized in that: The fractional frequency division unit uses one or more frequency dividers to realize the frequency division function.

5. A method for obtaining a blade vibration measurement key phase reference signal based on the signal generating device of claim 1, characterized in that: include: S1. After starting the signal generating device, the driving and conditioning module drives the speed measuring sensor to work under the control of the controller. The sensor generates a test speed signal with a repetition frequency of f. s , and f s =M·f r , where M is the number of grooves, barcodes or teeth of the tone wheel on the driving wheel shaft facing the speed measurement sensor probe, and f r is the speed of the driving wheel shaft; S2, the test speed signal is amplified and filtered by the drive and conditioning module and converted by the level conversion module to generate a pulse digital voltage signal. The digital voltage signal is frequency multiplied in the phase-locked frequency multiplication unit to generate a phase-locked frequency multiplication signal. The repetition frequency of the phase-locked frequency multiplication signal is f p , and f p =m1·M·f r , where m1 is the number of teeth on the driving wheel; S3, the phase-locked frequency multiplication signal is frequency-divided in the fractional frequency division unit to generate a blade vibration measurement key phase reference signal. The repetition frequency of the blade vibration measurement key phase reference signal is f o , and f o =m1 / m2·f r , where m2 is the number of teeth on the driven gear.

6. The method for obtaining a blade vibration measurement key phase reference signal according to claim 5, characterized in that: When the greatest common divisor of m1 and m2·M is N, the multiplication number of the phase-locked frequency multiplication unit in step S2 is m1 / N, which is implemented by configuring the frequency divider by the controller; the division number of the fractional frequency division unit in step S3 is m2·M / N, which is implemented by configuring the fractional frequency division unit by the controller.

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