CN111220101B - Rotor and stator axial clearance online measurement method and device based on microwaves - Google Patents

Rotor and stator axial clearance online measurement method and device based on microwaves Download PDF

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CN111220101B
CN111220101B CN202010076246.2A CN202010076246A CN111220101B CN 111220101 B CN111220101 B CN 111220101B CN 202010076246 A CN202010076246 A CN 202010076246A CN 111220101 B CN111220101 B CN 111220101B
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段发阶
牛广越
蒋佳佳
傅骁
程仲海
邓震宇
支烽耀
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Smartmens Tianjin Technology Co ltd
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    • G01—MEASURING; TESTING
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Abstract

The invention belongs to the field of non-contact distance measurement, and aims to realize non-contact real-time online accurate measurement of an axial clearance of a rotor and a stator of an aero-engine under a space-limited condition. The technical scheme includes that the rotor-stator axial gap online measuring device based on microwaves comprises a microwave signal generating module, a signal power amplifying module, a signal receiving and mixing module, a signal conditioning and collecting module, a circulator and a microwave sensor, wherein a carrier signal generated by the microwave signal generating module enters a first port of the circulator after being amplified by the signal power amplifying module and is output from a second port of the circulator; the second port of the circulator is connected with a microwave sensor, the microwave sensor transmits a carrier signal to the axial end face of the rotor to be tested, receives a carrier reflection signal of the axial end face of the rotor, outputs the carrier reflection signal back to the second port of the circulator and outputs the carrier reflection signal from the third port of the circulator. The invention is mainly applied to non-contact distance measurement occasions.

Description

Rotor and stator axial clearance online measurement method and device based on microwaves
Technical Field
The invention belongs to the field of non-contact distance measurement. Specifically, the invention relates to a rotor and stator axial gap online measurement method and device based on microwaves, in particular to a rotor and stator axial gap online measurement method and device adopting a carrier path and reference path cross frequency mixing structure and inhibiting same frequency interference signals.
Background
Modern aircraft engines are developing towards high thrust-weight ratio, high supercharging ratio and high pre-vortex temperature, on one hand, the aircraft engines are influenced by rotation speed change, temperature load and pneumatic load, a rotating shaft deforms under load, a casing deforms, the rotating shaft and the casing are inconsistent in thermal expansion, an excessively small axial gap can increase shaft work, the efficiency is reduced, the through-flow capacity is reduced, the pneumatic performance is deteriorated, and even a rotor and a stator are subjected to collision and abrasion, so that the safety and the reliability of the engines are influenced; on the other hand, the design of reducing the axial clearance is beneficial to shortening the size of the engine, enables the engine stages to be more compact, reduces the weight of the engine and effectively improves the thrust-weight ratio. At present, the active clearance control technology of the aircraft engine becomes one of the marking technologies of the modern engine, the acquisition and analysis of the running state parameters of the aircraft engine are the basis for realizing the active clearance control, and the non-contact on-line monitoring of the rotor and stator clearances of the aircraft engine has very important significance.
At present, the relatively mature non-contact rotor and stator clearance measuring method mainly aims at blade tip clearance, a bench test is completed, related research results at home and abroad of axial clearance are few, a calculated value of an engine prototype is generally used as a standard during actual assembly, installation clearance errors and clearance errors exist, and a mature rotor and stator axial clearance online measuring system does not exist.
In the traditional method for measuring the tiny clearance of the aero-engine, the optical method is easily influenced by environmental oil contamination, the measuring life is shortened, and the processing cost when the method is applied to a high-temperature (450 ℃) testing environment is very high; when the measuring range is 10mm, the diameter of the end surface of the probe reaches 60mm by a capacitance method, and the size of the sensor is too large, so that the method is not suitable for a measuring environment with very limited internal space of an aircraft engine; the eddy current method is only suitable for the working environment of the engine at normal temperature and low speed, and is not suitable for clearance measurement at high temperature; compared with other methods, the microwave method is not easily influenced by the internal working environment of the engine and is more suitable for measuring the tiny gap in the engine, but under the condition of limited space, the sensor is easy to receive the stray reflection signals of the static parts around the rotor part to be measured.
The microwave method can be divided into a reflection intensity method, a linear frequency modulation method and a phase difference method, the reflection intensity method is easily influenced by temperature, and the measurement precision cannot meet the measurement requirement; the linear frequency modulation method needs very high signal bandwidth to achieve higher measurement accuracy, but the structure is too complex; the phase difference method adopts orthogonal demodulation and high-low pass filtering methods to realize the measurement of the axial gap of the rotor and the stator, but the measurement precision of the axial gap is influenced by the same-frequency interference signals such as radio frequency leakage signals, end surface reflection signals of the sensor, stray reflection signals of the stator around the object to be measured and the like.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a rotor and stator axial clearance online measuring method and device based on microwaves, and non-contact real-time online accurate measurement of the rotor and stator axial clearance of an aero-engine under the condition of limited space is realized. Therefore, the technical scheme adopted by the invention is that the rotor-stator axial clearance online measuring device based on microwaves comprises a microwave signal generating module, a signal power amplifying module, a signal receiving and mixing module, a signal conditioning and collecting module, a circulator and a microwave sensor, wherein a carrier signal generated by the microwave signal generating module enters a first port of the circulator after being amplified by the signal power amplifying module and is output from a second port of the circulator; the second port of the circulator is connected with a microwave sensor, the microwave sensor transmits a carrier signal to the axial end face of the rotor to be tested, receives a carrier reflection signal of the axial end face of the rotor at the same time, outputs the carrier reflection signal back to the second port of the circulator and outputs the carrier reflection signal from the third port of the circulator;
the microwave signal generating module generates a reference signal which is amplified by the signal power amplifying module to be used as a local oscillator input signal Y of the signal receiving and frequency mixing module2(ii) a Meanwhile, the carrier signal generated by the microwave signal generating module is amplified by the signal power amplifying module and then is used as the radio frequency input signal X of the signal receiving and mixing module1(ii) a The signal receiving and mixing module outputs a path of demodulation signal, and the signal is output to a computer after being preprocessed by the signal conditioning and collecting module;
the carrier signal output by the third port of the circulator is used as the radio frequency input signal Y of the signal receiving and mixing module1(ii) a Meanwhile, the reference signal output by the microwave signal generation module is amplified by the signal power amplification module and then is used as a local oscillation input signal X of the signal receiving and frequency mixing module2(ii) a The signal receiving and mixing module outputs two paths of orthogonal demodulation signals, and the two paths of signals pass through the signal conditioning and collecting module and then are output to the computer.
One path of demodulation signal output by the signal receiving and mixing module forms a signal ZI1The signal receiving and mixing module outputs two paths of orthogonal demodulation signals to form a signal Z respectivelyI2And ZQ2In a computer, Z from the transmissionI2And ZI1Performing mixing operation and low-pass filtering to obtain signal VI(d) Is a reaction of ZQ2And ZI1Performing mixing operation and low-pass filtering to obtain signal VQ(d) By space distance scanning, i.e. rotor-stator axial gap sampling, at equal intervals, by VI(d) And VQ(d) And finally, calculating to obtain a rotor and stator axial clearance change value.
The microwave signal generating module mainly comprises: the system comprises a clock reference, a controller, a carrier circuit phase-locked loop, a carrier circuit voltage-controlled oscillator, a carrier circuit loop filter, a reference circuit phase-locked loop, a reference circuit voltage-controlled oscillator and a reference circuit loop filter;
the signal power amplification module includes: a carrier wave path power amplifier, a carrier wave path medium power amplifier, a reference path power amplifier and a reference path medium power amplifier;
the signal receiving and mixing module comprises: the device comprises a reference path mixer, a reference path radio frequency low noise amplifier, a carrier path mixer, a carrier path radio frequency low noise amplifier, a first low pass filter, a second low pass filter and a third low pass filter;
the clock reference provides a stable frequency reference for the system;
the controller sets the carrier wave path phase-locked loop to work at carrier frequency omegarIn the mode; the carrier wave circuit phase-locked loop outputs a pulse current signal through an internal charge pump, and the pulse current signal is subjected to band-pass filtering through a carrier wave circuit loop filter, so that the carrier wave circuit voltage-controlled oscillator outputs carrier frequency omegarSimultaneously, the phase difference between a frequency multiplication signal of the clock reference and a carrier feedback signal of the carrier circuit voltage-controlled oscillator is monitored in real time through an internal phase discriminator, and the phase difference between the two signals is zero;
after the power of a carrier circuit power amplifier is amplified, a carrier signal output by the carrier circuit voltage-controlled oscillator enters a first port of the circulator and is output from a second port of the circulator; the second port of the circulator is connected with a microwave sensor, the microwave sensor transmits a carrier signal to the axial end face of the rotor to be tested, receives a carrier reflection signal of the axial end face of the rotor at the same time, outputs the carrier reflection signal back to the second port of the circulator and outputs the carrier reflection signal from the third port of the circulator;
the controller sets the phase-locked loop of the reference path to work at the reference frequency omegasIn the mode; the reference circuit phase-locked loop outputs a pulse current signal through an internal charge pump, and after the pulse current signal is subjected to band-pass filtering through a reference circuit loop filter, the reference circuit voltage-controlled oscillator outputs a reference frequency omegasSimultaneously, the phase difference between a frequency multiplication signal of a clock reference and a reference feedback signal of a reference circuit voltage-controlled oscillator is monitored in real time through an internal phase discriminator, and the phase difference between the two signals is zero;
the reference signal output by the reference circuit voltage-controlled oscillator is used as a local oscillator input signal Y of the reference circuit frequency mixer after being amplified by the power amplifier of the reference circuit and the radio frequency low noise amplifier of the reference circuit2(ii) a Meanwhile, a carrier signal output by the carrier circuit voltage-controlled oscillator is amplified by the medium gain power of the medium power amplifier in the carrier circuit and then is used as a radio frequency input signal X of the reference circuit frequency mixer1(ii) a The reference path mixer outputs a path of demodulation signal which is Z after passing through a first low-pass filterI1The signal is pre-processed by a signal conditioning and collecting module and then transmitted to a computer;
the carrier signal output by the third port of the circulator is amplified by the carrier circuit radio frequency low noise amplifier and then is used as the radio frequency input signal Y of the carrier circuit mixer1(ii) a Meanwhile, a reference signal output by the reference circuit voltage-controlled oscillator is amplified by the medium gain of the medium power amplifier in the reference circuit and then is used as a local oscillator input signal X of the carrier circuit frequency mixer2(ii) a The carrier frequency mixer outputs two paths of orthogonal demodulation signals which are respectively subjected to a second low-pass filter and a third low-pass filter to form ZI2And ZQ2The two paths of signals are also transmitted to the computer after being preprocessed by the signal conditioning and collecting module;
reference roadLocal oscillator input signal Y input by frequency mixer2And a radio frequency input signal X1Represented by formula (1) and formula (2), respectively:
Figure BDA0002378560860000031
Figure BDA0002378560860000032
wherein A is1For the radio-frequency input signal X1Amplitude of (A)6For local oscillator input signal Y2Amplitude of (a), ωsAs reference frequency, ωrIs the carrier frequency and is,
Figure BDA0002378560860000033
for the radio-frequency input signal X1The phase of (a) is determined,
Figure BDA0002378560860000034
for local oscillator input signal Y2The phase of (d);
one path of demodulation signal output by the reference path mixer is filtered by a first low-pass filter to remove the frequency omegar+ωsAfter the frequency component of (2), the signal Z is obtainedI1Represented by formula (3):
Figure BDA0002378560860000035
wherein, ω isIF＝ωs-ωrIs an intermediate frequency;
radio frequency input signal Y input by carrier wave path mixer1And local oscillator input signal X2Represented by formula (4) and formula (5), respectively:
Figure BDA0002378560860000036
Figure BDA0002378560860000037
wherein A is2For local oscillator input signal X2Amplitude of (A)3For the radio-frequency input signal Y1Amplitude of the reflected signal portion of the intermediate carrier, A4For the radio-frequency input signal Y1Amplitude values of the end surface reflection part of the middle sensor and the stray reflection part of the stator around the rotor to be measured, A5For the radio-frequency input signal Y1The amplitude of the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator,
Figure BDA0002378560860000038
for local oscillator input signal X2The phase of (a) is determined,
Figure BDA0002378560860000039
for the radio-frequency input signal Y1The phase positions of the middle carrier wave reflected signal part, the sensor end surface reflected part and the stator stray reflected part around the rotor to be measured delayed on the transmission cable,
Figure BDA00023785608600000310
for the radio-frequency input signal Y1Wherein the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator delays the phase on the transmission path,
Figure BDA00023785608600000311
for the radio-frequency input signal Y1The middle carrier reflected signal part is subjected to the phase to be detected generated by the change of the rotor stator axial gap;
two paths of orthogonal demodulation signals output by the carrier path mixer are respectively filtered by a second low-pass filter and a third low-pass filter to remove omega frequencyr+ωsAfter the frequency component of (2), the signal Z is obtainedI2And ZQ2Expressed by the following formulae (6) and (7):
ZI2＝SI_IF(t)+SI_tip(t)+SI_le(t) (6)
ZQ2＝SQ_IF(t)+SQ_tip(t)+SQ_le(t) (7)
wherein,
Figure BDA0002378560860000041
is ZI2The carrier reflection signal portion of (1);
Figure BDA0002378560860000042
is ZI2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure BDA0002378560860000043
is ZI2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
Figure BDA0002378560860000044
is ZQ2The carrier reflection signal portion of (1);
Figure BDA0002378560860000045
is ZQ2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure BDA0002378560860000046
is ZQ2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
k is a factor of the amplitude imbalance,
Figure BDA00023785608600000416
is a phase imbalance factor;
in a computer, Z from the transmissionI2And ZI1Performing mixing operation and low-pass filtering to obtain signal VI(d) Is a reaction of ZQ2And ZI1Performing mixing operation and low-pass filtering to obtain signal VQ(d)，VI(d) And VQ(d) Represented by formulas (8) and (9), respectively:
Figure BDA0002378560860000048
Figure BDA0002378560860000049
wherein,
Figure BDA00023785608600000410
Figure BDA00023785608600000411
when the temperature of the working environment is stable and unchanged and the vibration state of the sensor installation environment is stable and unchanged,
Figure BDA00023785608600000412
Atip、Aleare constant and do not vary with rotor-stator axial clearance, and AIFOnly the rotor and stator axial clearance is related, and the inverse proportion relation is formed by the second power of the rotor and stator axial clearance d;
based on the microwave phase ranging principle:
Figure BDA00023785608600000413
wherein ω is1Is the spatial angular frequency of the transmitted microwave radio frequency signal;
obtained from formulae (8), (9), (10):
Figure BDA00023785608600000414
wherein,
Figure BDA00023785608600000415
j is an imaginary unit.
Using the frequency spectrum of V (d) signal mainly at main frequency omega1Image frequency-omega1And the DC frequency, the amplitude values at the three frequencies are respectively A (omega) through space distance scanning, namely, rotor and stator axial gap sampling at equal intervals1)、A(-ω1) A (0); the amplitude-phase imbalance correction factor is expressed by equation (12), equation (13), equation (14), and equation (15):
Figure BDA0002378560860000051
Figure BDA0002378560860000052
Figure BDA0002378560860000053
Figure BDA0002378560860000054
establishing a model for inhibiting co-channel interference signals, as shown in formula (17):
Figure BDA0002378560860000055
therefore, the rotor-stator axial gap d after the suppression of the co-channel interference signal is expressed by equation (18):
Figure BDA0002378560860000056
wherein,
Figure BDA0002378560860000057
the constant value is obtained by calibration without changing with the axial clearance of the rotor and the stator to be measured。
The rotor and stator axial clearance on-line measuring method based on microwaves is realized by utilizing the device, wherein:
local oscillator input signal Y input by reference path mixer2And a radio frequency input signal X1Represented by formula (1) and formula (2), respectively:
Figure BDA0002378560860000058
Figure BDA0002378560860000059
wherein A is1For the radio-frequency input signal X1Amplitude of (A)6For local oscillator input signal Y2Amplitude of (a), ωsAs reference frequency, ωrIs the carrier frequency and is,
Figure BDA00023785608600000510
for the radio-frequency input signal X1The phase of (a) is determined,
Figure BDA00023785608600000511
for local oscillator input signal Y2The phase of (d);
one path of demodulation signal output by the reference path mixer is filtered by a first low-pass filter to remove the frequency omegar+ωsAfter the frequency component of (2), the signal Z is obtainedI1Represented by formula (3):
Figure BDA00023785608600000512
wherein, ω isIF＝ωs-ωrIs an intermediate frequency;
radio frequency input signal Y input by carrier wave path mixer1And local oscillator input signal X2Represented by formula (4) and formula (5), respectively:
Figure BDA00023785608600000513
Figure BDA00023785608600000514
wherein A is2For local oscillator input signal X2Amplitude of (A)3For the radio-frequency input signal Y1Amplitude of the reflected signal portion of the intermediate carrier, A4For the radio-frequency input signal Y1Amplitude values of the end surface reflection part of the middle sensor and the stray reflection part of the stator around the rotor to be measured, A5For the radio-frequency input signal Y1The amplitude of the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator,
Figure BDA00023785608600000515
for local oscillator input signal X2The phase of (a) is determined,
Figure BDA00023785608600000516
for the radio-frequency input signal Y1The phase positions of the middle carrier wave reflected signal part, the sensor end surface reflected part and the stator stray reflected part around the rotor to be measured delayed on the transmission cable,
Figure BDA0002378560860000061
for the radio-frequency input signal Y1Wherein the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator delays the phase on the transmission path,
Figure BDA0002378560860000062
for the radio-frequency input signal Y1The middle carrier reflected signal part is subjected to the phase to be detected generated by the change of the rotor stator axial gap;
two paths of orthogonal demodulation signals output by the carrier path mixer are respectively filtered by a second low-pass filter and a third low-pass filter to remove omega frequencyr+ωsAfter the frequency component of (2), the signal Z is obtainedI2And ZQ2Respectively expressed by formula (6) and formula (7)The following steps:
ZI2＝SI_IF(t)+SI_tip(t)+SI_le(t) (6)
ZQ2＝SQ_IF(t)+SQ_tip(t)+SQ_le(t) (7)
wherein,
Figure BDA0002378560860000063
is ZI2The carrier reflection signal portion of (1);
Figure BDA0002378560860000064
is ZI2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure BDA00023785608600000614
is ZI2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
Figure BDA0002378560860000065
is ZQ2The carrier reflection signal portion of (1);
Figure BDA0002378560860000066
is ZQ2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure BDA0002378560860000067
is ZQ2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
k is a factor of the amplitude imbalance,
Figure BDA0002378560860000068
is a phase imbalance factor;
in a computer, Z from the transmissionI2And ZI1Performing mixing operation and low-pass filtering to obtain signal VI(d) Is a reaction of ZQ2And ZI1Performing mixing operation and low-pass filtering to obtain signal VQ(d)，VI(d) And VQ(d) Represented by formulas (8) and (9), respectively:
Figure BDA0002378560860000069
Figure BDA00023785608600000610
wherein,
Figure BDA00023785608600000611
Figure BDA00023785608600000612
when the temperature of the working environment is stable and unchanged and the vibration state of the sensor installation environment is stable and unchanged,
Figure BDA00023785608600000613
Atip、Aleare constant and do not vary with rotor-stator axial clearance, and AIFOnly the rotor and stator axial clearance is related, and the inverse proportion relation is formed by the second power of the rotor and stator axial clearance d;
based on the microwave phase ranging principle:
Figure BDA0002378560860000071
wherein ω is1Is the spatial angular frequency of the transmitted microwave radio frequency signal;
obtained from formulae (8), (9), (10):
Figure BDA0002378560860000072
wherein,
Figure BDA0002378560860000073
j is an imaginary unit.
Using the frequency spectrum of V (d) signal mainly at main frequency omega1Image frequency-omega1And the DC frequency, the amplitude values at the three frequencies are respectively A (omega) through space distance scanning, namely, rotor and stator axial gap sampling at equal intervals1)、A(-ω1) A (0); the amplitude-phase imbalance correction factor is expressed by equation (12), equation (13), equation (14), and equation (15):
Figure BDA0002378560860000074
Figure BDA0002378560860000075
Figure BDA0002378560860000076
Figure BDA0002378560860000077
establishing a model for inhibiting co-channel interference signals, as shown in formula (17):
Figure BDA0002378560860000078
therefore, the rotor-stator axial gap d after the suppression of the co-channel interference signal is expressed by equation (18):
Figure BDA0002378560860000079
wherein,
Figure BDA00023785608600000710
the constant value is obtained by calibration without changing with the axial clearance of the rotor and the stator to be measured.
The invention has the characteristics and beneficial effects that:
the method breaks through the current situation that no mature rotor and stator axial clearance measuring scheme exists at home and abroad, and solves the problem that the axial clearance measuring precision is influenced by same-frequency interference signals such as radio frequency leakage signals, sensor end face reflection signals and stator stray reflection signals around a to-be-measured object when the rotor and stator axial clearance is measured by the existing microwave type micro clearance measuring method based on the phase difference method. A rotor and stator axial gap online measurement method and device based on microwaves are designed, a carrier path and reference path cross frequency mixing structure based on a phase distance measurement principle is utilized, a same frequency interference signal suppression method based on spatial distance scanning is provided, and measurement accuracy of rotor and stator axial gaps is improved under the condition that the same frequency interference signals such as radio frequency leakage signals from a transmitting end to a receiving end, end face reflection signals of a microwave sensor, stray reflection signals of stator parts around a rotor to be measured and the like exist.
Description of the drawings:
fig. 1 shows a schematic diagram of the microwave-based rotor-stator axial gap online measurement method and device.
In fig. 1: 1 is a clock reference, 2 is a controller, 3 is a carrier circuit phase-locked loop, 4 is a carrier circuit voltage-controlled oscillator, 5 is a carrier circuit loop filter, 6 is a reference circuit phase-locked loop, 7 is a reference circuit voltage-controlled oscillator, 8 is a reference circuit loop filter, 9 is a carrier circuit power amplifier, 10 is a carrier circuit medium power amplifier, 11 is a reference circuit power amplifier, 12 is a reference circuit medium power amplifier, 13 is a reference circuit mixer, 14 is a reference circuit radio frequency low noise amplifier, 15 is a carrier circuit mixer, 16 is a carrier circuit radio frequency low noise amplifier, 17 is a first low pass filter, 18 is a second low pass filter, 19 is a third low pass filter, 20 is a microwave signal generating module, 21 is a signal power amplifying module, 22 is a signal receiving and mixing module, 23 is a signal conditioning and collecting module, 24 is a computer, 25 is a circulator, the microwave sensor 26 and the rotor axial end face 27 are shown.
Detailed Description
In order to overcome the defects in the prior art, the invention designs a rotor-stator axial clearance online measuring method and a device based on microwaves, and mainly solves the technical problems that:
the method breaks through the current situation that no mature rotor and stator axial clearance measuring scheme exists at home and abroad, and solves the problem that the axial clearance measuring precision is influenced by same-frequency interference signals such as radio frequency leakage signals, sensor end face reflection signals and stator stray reflection signals around a to-be-measured object when the rotor and stator axial clearance is measured by the existing microwave type micro clearance measuring method based on the phase difference method. A rotor and stator axial gap online measurement method and device based on microwaves are designed, a carrier path and reference path cross frequency mixing structure based on a phase distance measurement principle is utilized, a same frequency interference signal suppression method based on spatial distance scanning is provided, and measurement accuracy of rotor and stator axial gaps is improved under the condition that the same frequency interference signals such as radio frequency leakage signals from a transmitting end to a receiving end, end face reflection signals of a microwave sensor, stray reflection signals of stator parts around a rotor to be measured and the like exist.
In order to achieve the above object, the present invention adopts a technical solution that a microwave-based rotor-stator axial gap online measurement method and device are designed, as shown in fig. 1, and mainly include: the microwave signal generating module 20, the signal power amplifying module 21, the signal receiving and mixing module 22, the signal conditioning and collecting module 23, the computer 24, the circulator 25 and the microwave sensor 26;
the microwave signal generating module 20 mainly includes: the system comprises a clock reference 1, a controller 2, a carrier circuit phase-locked loop 3, a carrier circuit voltage-controlled oscillator 4, a carrier circuit loop filter 5, a reference circuit phase-locked loop 6, a reference circuit voltage-controlled oscillator 7 and a reference circuit loop filter 8;
the signal power amplification module 21 mainly includes: a carrier wave path power amplifier 9, a carrier wave path medium power amplifier 10, a reference path power amplifier 11 and a reference path medium power amplifier 12;
the signal receiving and mixing module 22 mainly includes: a reference path mixer 13, a reference path radio frequency low noise amplifier 14, a carrier path mixer 15, a carrier path radio frequency low noise amplifier 16, a first low pass filter 17, a second low pass filter 18 and a third low pass filter 19;
further, a rotor and stator axial gap online measuring device based on microwave is a coherent measurement system, and a clock reference 1 provides a stable frequency reference for the system;
further, the controller 2 sets the carrier phase-locked loop 3 to operate at the carrier frequency ωrIn the mode; the carrier wave circuit phase-locked loop 3 outputs a pulse current signal through an internal charge pump, and after the pulse current signal is subjected to band-pass filtering through the carrier wave circuit loop filter 5, the carrier wave circuit voltage-controlled oscillator 4 outputs carrier frequency omegarSimultaneously, the phase difference between the frequency multiplication signal of the clock reference 1 and the carrier feedback signal of the carrier circuit voltage-controlled oscillator 4 is monitored in real time through an internal phase discriminator, and the phase difference between the two signals is zero;
further, the carrier signal output by the carrier circuit voltage-controlled oscillator 4 enters the first port of the circulator 25 after being power-amplified by the carrier circuit power amplifier 9, and is output from the second port of the circulator 25 with a smaller insertion loss; the second port of the circulator 25 is connected with a microwave sensor 26, the microwave sensor 26 transmits a carrier signal to the axial end face 27 of the rotor to be tested, receives a carrier reflection signal of the axial end face 27 of the rotor, outputs the carrier reflection signal to the second port of the circulator 25, and outputs the carrier reflection signal from the third port of the circulator 25 with smaller insertion loss;
further, the controller 2 sets the reference phase-locked loop 6 to operate at the reference frequency ωsIn the mode; the reference circuit phase-locked loop 6 outputs a pulse current signal through an internal charge pump, and after the pulse current signal is subjected to band-pass filtering through a reference circuit loop filter 8, the reference circuit voltage-controlled oscillator 7 outputs a reference frequency omegasSimultaneously, the phase difference between the frequency multiplication signal of the clock reference 1 and the reference feedback signal of the reference circuit voltage-controlled oscillator 7 is monitored in real time through an internal phase discriminator, and the phase difference between the two signals is zero;
further, the reference signal output by the reference path voltage-controlled oscillator 7 is subjected to parameterThe amplified power of the reference path power amplifier 11 and the amplified power of the reference path radio frequency low noise amplifier 14 are used as the local oscillation input signal Y of the reference path mixer 132(ii) a Meanwhile, the carrier signal output by the carrier circuit voltage-controlled oscillator 4 is amplified by the medium gain power of the medium power amplifier 6 in the carrier circuit and then is used as the radio frequency input signal X of the reference circuit mixer 131(ii) a The reference channel mixer 13 outputs a demodulated signal, which is Z after passing through the first low pass filter 17I1The signal is preprocessed by the signal conditioning and collecting module 23 and then transmitted to the computer 24;
further, the carrier signal output from the third port of the circulator 25 is amplified by the carrier path rf low noise amplifier 16 and then used as the rf input signal Y of the carrier path mixer 151(ii) a Meanwhile, the reference signal output by the reference circuit voltage-controlled oscillator 7 is amplified by the medium gain of the reference circuit medium power amplifier 12 and then is used as the local oscillator input signal X of the carrier circuit mixer 152(ii) a The carrier mixer 15 outputs two orthogonal demodulation signals, which are respectively passed through the second low-pass filter 18 and the third low-pass filter 19 and become ZI2And ZQ2The two paths of signals are also preprocessed by the signal conditioning and collecting module 23 and then transmitted to the computer 24;
furthermore, the signal receiving and mixing module 22 of the present invention adopts a carrier-way and reference-way cross mixing structure, that is, of two signals uploaded to a computer, one of the signals is obtained by using a carrier-way carrier signal as a radio frequency input signal and a reference-way reference signal as local oscillation input signals, mixing the two signals in the reference-way mixer 13, the other signal is obtained by using a carrier-way carrier signal as a radio frequency input signal and a reference-way reference signal as local oscillation input signals, mixing the two signals in the carrier-way mixer 15, and mixing the 2-way signal output by the carrier-way voltage-controlled oscillator 4 and the 2-way signal output by the reference-way voltage-controlled oscillator 7 in the reference way and the carrier way respectively, which is called as a carrier-way and reference-way cross mixing structure;
the carrier circuit and reference circuit cross mixing structure adopted by the invention can inhibit the influence of low frequency stability of output signals of the carrier circuit voltage-controlled oscillator 4 or the reference circuit voltage-controlled oscillator 7 or the frequency drift along with the temperature on the axial clearance measurement precision of the rotor;
further, the local oscillator input signal Y input by the reference path mixer 132And a radio frequency input signal X1May be represented by formula 1 and formula 2, respectively:
Figure BDA0002378560860000091
Figure BDA0002378560860000092
wherein A is1For the radio-frequency input signal X1Amplitude of (A)6For local oscillator input signal Y2Amplitude of (a), ωsAs reference frequency, ωrIs the carrier frequency and is,
Figure BDA0002378560860000093
for the radio-frequency input signal X1The phase of (a) is determined,
Figure BDA0002378560860000094
for local oscillator input signal Y2The phase of (d);
one path of demodulated signal output by the reference path mixer 13 is filtered by a first low pass filter 17 to remove the frequency ωr+ωsAfter the frequency component of (2), the signal Z is obtainedI1Can be represented by formula 3:
Figure BDA0002378560860000101
wherein, ω isIF＝ωs-ωrIs an intermediate frequency;
further, a radio frequency input signal Y inputted from the carrier mixer 151And local oscillator input signal X2May be represented by formula 4 and formula 5, respectively:
Figure BDA0002378560860000102
Figure BDA0002378560860000103
wherein A is2For local oscillator input signal X2Amplitude of (A)3For the radio-frequency input signal Y1Amplitude of the reflected signal portion of the intermediate carrier, A4For the radio-frequency input signal Y1Amplitude values of the end surface reflection part of the middle sensor and the stray reflection part of the stator around the rotor to be measured, A5For the radio-frequency input signal Y1The amplitude of the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator,
Figure BDA0002378560860000104
for local oscillator input signal X2The phase of (a) is determined,
Figure BDA0002378560860000105
for the radio-frequency input signal Y1The phase positions of the middle carrier wave reflected signal part, the sensor end surface reflected part and the stator stray reflected part around the rotor to be measured delayed on the transmission cable,
Figure BDA0002378560860000106
for the radio-frequency input signal Y1Wherein the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator delays the phase on the transmission path,
Figure BDA0002378560860000107
for the radio-frequency input signal Y1The middle carrier reflected signal part is subjected to the phase to be detected generated by the change of the rotor stator axial gap;
two paths of orthogonal demodulation signals output by the carrier path mixer 15 are respectively filtered by a second low-pass filter 18 and a third low-pass filter 19 to remove omegar+ωsAfter the frequency component of (2), the signal Z is obtainedI2And ZQ2And can be represented by formula 6 and formula 7, respectively:
ZI2＝SI_IF(t)+SI_tip(t)+SI_le(t) (6)
ZQ2＝SQ_IF(t)+SQ_tip(t)+SQ_le(t) (7)
wherein,
Figure BDA0002378560860000108
is ZI2The carrier reflection signal portion of (1);
Figure BDA0002378560860000109
is ZI2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure BDA00023785608600001010
is ZI2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
Figure BDA00023785608600001011
is ZQ2The carrier reflection signal portion of (1);
Figure BDA00023785608600001012
is ZQ2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure BDA00023785608600001013
is ZQ2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
k is a factor of the amplitude imbalance,
Figure BDA00023785608600001014
is a phase imbalance factor;
further, in the computer 24, Z from the transmission is transmittedI2And ZI1Performing mixing operation and low-pass filtering to obtain signal VI(d) Is a reaction of ZQ2And ZI1Performing mixing operation and low-pass filtering to obtain signal VQ(d)，VI(d) And VQ(d) Can be represented by formulas 8 and 9, respectively:
Figure BDA0002378560860000111
Figure BDA0002378560860000112
wherein,
Figure BDA0002378560860000113
Figure BDA0002378560860000114
when the temperature of the working environment is stable and unchanged and the vibration state of the sensor installation environment is stable and unchanged,
Figure BDA0002378560860000115
Atip、Aleare constant and do not vary with rotor-stator axial clearance, and AIFOnly the rotor and stator axial clearance is related, and the inverse proportion relation is formed by the second power of the rotor and stator axial clearance d;
further, based on the principle of microwave phase distance measurement, the method comprises
Figure BDA0002378560860000116
Wherein ω is1Is the spatial angular frequency of the transmitted microwave radio frequency signal;
the following formulas 8, 9 and 10 can be obtained:
Figure BDA0002378560860000117
wherein,
Figure BDA0002378560860000118
j is an imaginary unit.
Furthermore, the invention utilizes the V (d) signal frequency spectrum to be mainly at the main frequency omega1Image frequency-omega1And the DC frequency, the amplitude values at the three frequencies are respectively A (omega) through space distance scanning, namely, rotor and stator axial gap sampling at equal intervals1)、A(-ω1) A (0); the amplitude-phase imbalance correction factor can be expressed by equations 12, 13, 14 and 15:
Figure BDA0002378560860000119
Figure BDA00023785608600001110
Figure BDA00023785608600001111
Figure BDA00023785608600001112
further, the invention provides a co-frequency interference signal suppression method based on spatial distance scanning, which can effectively suppress co-frequency interference signals such as radio frequency leakage signals, end face reflection signals of a microwave sensor, stray reflection signals of static parts around a rotor to be detected and the like from crosstalk of a transmitting end to a receiving end by using an amplitude-phase imbalance correction factor;
the model for suppressing co-channel interference signals is shown in formula 17:
Figure BDA00023785608600001113
therefore, the rotor-stator axial gap d after the co-channel interference signal is suppressed can be represented by equation 18:
Figure BDA0002378560860000121
wherein,
Figure BDA0002378560860000122
the constant value can be obtained by calibration without changing with the axial clearance of the rotor and the stator to be measured.
The present invention will be described in further detail with reference to the accompanying drawings and specific examples.
The invention designs a rotor and stator axial clearance online measurement method and a device based on microwaves, which adopt a carrier wave path and reference path cross frequency mixing structure and a co-channel interference signal suppression method based on space distance scanning to realize non-contact real-time online accurate measurement of the rotor and stator axial clearance of an aeroengine under the condition of space limitation.
The invention is realized by the following steps:
the invention designs a rotor and stator axial clearance on-line measuring method and device based on microwave, as shown in figure 1, mainly comprising: the microwave signal generating module 20, the signal power amplifying module 21, the signal receiving and mixing module 22, the signal conditioning and collecting module 23, the computer 24, the circulator 25 and the microwave sensor 26;
the microwave signal generating module 20 mainly includes: the system comprises a clock reference 1, a controller 2, a carrier circuit phase-locked loop 3, a carrier circuit voltage-controlled oscillator 4, a carrier circuit loop filter 5, a reference circuit phase-locked loop 6, a reference circuit voltage-controlled oscillator 7 and a reference circuit loop filter 8;
the signal power amplification module 21 mainly includes: a carrier wave path power amplifier 9, a carrier wave path medium power amplifier 10, a reference path power amplifier 11 and a reference path medium power amplifier 12;
the signal receiving and mixing module 22 mainly includes: a reference path mixer 13, a reference path radio frequency low noise amplifier 14, a carrier path mixer 15, a carrier path radio frequency low noise amplifier 16, a first low pass filter 17, a second low pass filter 18 and a third low pass filter 19;
the invention is further described with reference to the following figures and examples.
Further, in the invention, the rotor and stator axial gap online measuring device based on microwave is a coherent measurement system, the clock reference 1 provides stable frequency reference for the system, and an analog temperature compensation crystal oscillator, a digital temperature compensation crystal oscillator and the like with high frequency stability can be selected;
further, in the invention, the controller 2 sets the carrier wave path phase-locked loop 3 to work under the carrier frequency; the carrier circuit phase-locked loop 3 outputs a pulse current signal through an internal charge pump, after the pulse current signal is subjected to band-pass filtering through a carrier circuit loop filter 5, the carrier circuit voltage-controlled oscillator 4 outputs a carrier signal, and simultaneously, through an internal phase discriminator, the phase difference between a frequency multiplication signal of a clock reference 1 and a carrier feedback signal of the carrier circuit voltage-controlled oscillator 4 is monitored in real time and is enabled to be zero;
further, in the invention, the controller 2 can be a single chip microcomputer, an advanced reduced instruction set machine (ARM) and the like;
further, in the invention, the carrier wave path phase-locked loop 3 can be selected from an analog phase-locked loop, a digital phase-locked loop and the like;
further, in the present invention, the carrier circuit loop filter 5 may be a passive filter, an active filter, or the like;
further, in the present invention, the carrier signal output by the carrier circuit voltage-controlled oscillator 4 enters the first port of the circulator 25 after being power-amplified by the carrier circuit power amplifier 9, and is output from the second port of the circulator 25 with a smaller insertion loss; the second port of the circulator 25 is connected with a microwave sensor 26, the microwave sensor 26 transmits a carrier signal to the axial end face 27 of the rotor to be tested, receives a carrier reflection signal of the axial end face 27 of the rotor, outputs the carrier reflection signal to the second port of the circulator 25, and outputs the carrier reflection signal from the third port of the circulator 25 with smaller insertion loss;
further, in the present invention, the circulator 25 may be selected from a surface mount circulator, a wire circulator, a coaxial circulator, etc.;
further, in the present invention, the microwave sensor 26 may be a microwave resonant cavity structure, a microstrip antenna structure, a planar inverted-F antenna structure, or the like;
further, in the invention, the controller 2 sets the reference path phase-locked loop 6 to work under the reference frequency; the reference path phase-locked loop 6 outputs a pulse current signal through an internal charge pump, after the pulse current signal is subjected to band-pass filtering through a reference path loop filter 8, the reference path voltage-controlled oscillator 7 outputs a reference signal, and simultaneously, through an internal phase discriminator, the phase difference between a frequency multiplication signal of the clock reference 1 and a reference feedback signal of the reference path voltage-controlled oscillator 7 is monitored in real time and is enabled to be zero;
further, in the invention, the reference phase-locked loop 6 can be selected from an analog phase-locked loop, a digital phase-locked loop and the like;
further, in the present invention, the reference loop filter 8 may be a passive filter, an active filter, or the like;
further, in the present invention, a reference signal output by the reference path voltage-controlled oscillator 7 is amplified by the power of the reference path power amplifier 11 and the reference path radio frequency low noise amplifier 14 to be used as a local oscillation input signal of the reference path mixer 13; meanwhile, a carrier signal output by the carrier circuit voltage-controlled oscillator 4 is amplified by the medium gain power of the medium power amplifier 10 in the carrier circuit and then is used as a radio frequency input signal of the reference circuit mixer 13; the reference channel mixer 13 outputs a demodulated signal, which is Z after passing through the first low pass filter 17I1The signal is preprocessed by the signal conditioning and collecting module 23 and then transmitted to the computer 24;
further, in the present invention, the carrier signal output from the third port of the circulator 25 is amplified by the carrier path rf low-noise amplifier 16 and then used as the rf input signal of the carrier path mixer 15; meanwhile, a reference signal output by the reference path voltage-controlled oscillator 7 is amplified by a medium gain of the reference path medium power amplifier 12 and then is used as a local oscillator input signal of the carrier path mixer 15; the carrier mixer 15 outputs two orthogonal demodulation signals, which are respectively passed through the second low-pass filter 18 and the third low-pass filter 19 and become ZI2And ZQ2The two signals also pass throughAfter being preprocessed by the signal conditioning and collecting module 23, the signals are transmitted to the computer 24;
further, in the present invention, the signal conditioning and collecting module 23 may be composed of a signal amplifying circuit, a signal filtering circuit and an analog-digital converting circuit;
further, in the present invention, the computer 24 may be an industrial control computer, a general personal computer, or the like;
further, in the present invention, Z is transmitted from the computer 24I2And ZI1Performing mixing operation and low-pass filtering to obtain signal VI(d) Is a reaction of ZQ2And ZI1Performing mixing operation and low-pass filtering to obtain signal VQ(d)；
Further, the invention provides a co-frequency interference signal suppression method based on spatial distance scanning, which can effectively suppress co-frequency interference signals such as radio frequency leakage signals, end face reflection signals of a microwave sensor, stray reflection signals of static parts around a rotor to be detected and the like from crosstalk of a transmitting end to a receiving end by using an amplitude-phase imbalance correction factor; the model for suppressing co-channel interference signals is shown in the foregoing formula 17;
further, in the present invention, the rotor axial gap d after the co-channel interference signal is suppressed can be represented by the foregoing formula 18.

Claims (4)

1. A rotor-stator axial clearance on-line measuring device based on microwave is characterized by comprising a microwave signal generating module, a signal power amplifying module, a signal receiving and mixing module, a signal conditioning and collecting module, a circulator and a microwave sensor, wherein a carrier signal generated by the microwave signal generating module enters a first port of the circulator after being amplified by the signal power amplifying module and is output from a second port of the circulator; the second port of the circulator is connected with a microwave sensor, the microwave sensor transmits a carrier signal to the axial end face of the rotor to be tested, receives a carrier reflection signal of the axial end face of the rotor at the same time, outputs the carrier reflection signal back to the second port of the circulator and outputs the carrier reflection signal from the third port of the circulator;
the microwave signal generating module generates a reference signalAmplified by the signal power amplifying module to be used as a local oscillator input signal Y of the signal receiving and frequency mixing module2(ii) a Meanwhile, the carrier signal generated by the microwave signal generating module is amplified by the signal power amplifying module and then is used as the radio frequency input signal X of the signal receiving and mixing module1(ii) a The signal receiving and mixing module outputs a path of demodulation signal, and the signal is output to a computer after being preprocessed by the signal conditioning and collecting module;
the carrier signal output by the third port of the circulator is used as the radio frequency input signal Y of the signal receiving and mixing module1(ii) a Meanwhile, the reference signal output by the microwave signal generation module is amplified by the signal power amplification module and then is used as a local oscillation input signal X of the signal receiving and frequency mixing module2(ii) a The signal receiving and mixing module outputs two paths of orthogonal demodulation signals, and the two paths of signals pass through the signal conditioning and collecting module and then are output to the computer.
2. The microwave-based rotor-stator axial gap on-line measuring device of claim 1, wherein a path of demodulated signal output from the signal receiving and mixing module forms a signal ZI1The signal receiving and mixing module outputs two paths of orthogonal demodulation signals to form a signal Z respectivelyI2And ZQ2In a computer, Z from the transmissionI2And ZI1Performing mixing operation and low-pass filtering to obtain signal VI(d) Is a reaction of ZQ2And ZI1Performing mixing operation and low-pass filtering to obtain signal VQ(d) By space distance scanning, i.e. rotor-stator axial gap sampling, at equal intervals, by VI(d) And VQ(d) And finally, calculating to obtain a rotor and stator axial clearance change value.
3. The microwave-based rotor-stator axial gap on-line measuring device as claimed in claim 1, wherein the microwave signal generating module mainly comprises: the system comprises a clock reference, a controller, a carrier circuit phase-locked loop, a carrier circuit voltage-controlled oscillator, a carrier circuit loop filter, a reference circuit phase-locked loop, a reference circuit voltage-controlled oscillator and a reference circuit loop filter;
the signal power amplification module includes: a carrier wave path power amplifier, a carrier wave path medium power amplifier, a reference path power amplifier and a reference path medium power amplifier;
the signal receiving and mixing module comprises: the device comprises a reference path mixer, a reference path radio frequency low noise amplifier, a carrier path mixer, a carrier path radio frequency low noise amplifier, a first low pass filter, a second low pass filter and a third low pass filter;
the clock reference provides a stable frequency reference for the system;
the controller sets the carrier wave path phase-locked loop to work at carrier frequency omegarIn the mode; the carrier wave circuit phase-locked loop outputs a pulse current signal through an internal charge pump, and the pulse current signal is subjected to band-pass filtering through a carrier wave circuit loop filter, so that the carrier wave circuit voltage-controlled oscillator outputs carrier frequency omegarSimultaneously, the phase difference between a frequency multiplication signal of the clock reference and a carrier feedback signal of the carrier circuit voltage-controlled oscillator is monitored in real time through an internal phase discriminator, and the phase difference between the two signals is zero;
after the power of a carrier circuit power amplifier is amplified, a carrier signal output by the carrier circuit voltage-controlled oscillator enters a first port of the circulator and is output from a second port of the circulator; the second port of the circulator is connected with a microwave sensor, the microwave sensor transmits a carrier signal to the axial end face of the rotor to be tested, receives a carrier reflection signal of the axial end face of the rotor at the same time, outputs the carrier reflection signal back to the second port of the circulator and outputs the carrier reflection signal from the third port of the circulator;
the controller sets the phase-locked loop of the reference path to work at the reference frequency omegasIn the mode; the reference circuit phase-locked loop outputs a pulse current signal through an internal charge pump, and after the pulse current signal is subjected to band-pass filtering through a reference circuit loop filter, the reference circuit voltage-controlled oscillator outputs a reference frequency omegasSimultaneously, the phase difference between a frequency multiplication signal of a clock reference and a reference feedback signal of a reference circuit voltage-controlled oscillator is monitored in real time through an internal phase discriminator, and the phase difference between the two signals is zero;
reference path power of reference signal output by reference path voltage-controlled oscillatorThe amplified power of the amplifier and the amplified reference circuit radio frequency low noise amplifier are used as the local oscillation input signal Y of the reference circuit frequency mixer2(ii) a Meanwhile, a carrier signal output by the carrier circuit voltage-controlled oscillator is amplified by the medium gain power of the medium power amplifier in the carrier circuit and then is used as a radio frequency input signal X of the reference circuit frequency mixer1(ii) a The reference path mixer outputs a path of demodulation signal which is Z after passing through a first low-pass filterI1The signal is pre-processed by a signal conditioning and collecting module and then transmitted to a computer;
the carrier signal output by the third port of the circulator is amplified by the carrier circuit radio frequency low noise amplifier and then is used as the radio frequency input signal Y of the carrier circuit mixer1(ii) a Meanwhile, a reference signal output by the reference circuit voltage-controlled oscillator is amplified by the medium gain of the medium power amplifier in the reference circuit and then is used as a local oscillator input signal X of the carrier circuit frequency mixer2(ii) a The carrier frequency mixer outputs two paths of orthogonal demodulation signals which are respectively subjected to a second low-pass filter and a third low-pass filter to form ZI2And ZQ2The two paths of signals are also transmitted to the computer after being preprocessed by the signal conditioning and collecting module;
local oscillator input signal Y input by reference path mixer2And a radio frequency input signal X1Represented by formula (1) and formula (2), respectively:
Figure FDA0002976724230000021
Figure FDA0002976724230000022
wherein A is1For the radio-frequency input signal X1Amplitude of (A)6For local oscillator input signal Y2Amplitude of (a), ωsAs reference frequency, ωrIs the carrier frequency and is,
Figure FDA0002976724230000023
is a radio frequencyInput signal X1The phase of (a) is determined,
Figure FDA0002976724230000024
for local oscillator input signal Y2The phase of (d);
one path of demodulation signal output by the reference path mixer is filtered by a first low-pass filter to remove the frequency omegar+ωsAfter the frequency component of (2), the signal Z is obtainedI1Represented by formula (3):
Figure FDA0002976724230000025
wherein, ω isIF＝ωs-ωrIs an intermediate frequency;
radio frequency input signal Y input by carrier wave path mixer1And local oscillator input signal X2Represented by formula (4) and formula (5), respectively:
Figure FDA0002976724230000026
Figure FDA0002976724230000027
wherein A is2For local oscillator input signal X2Amplitude of (A)3For the radio-frequency input signal Y1Amplitude of the reflected signal portion of the intermediate carrier, A4For the radio-frequency input signal Y1Amplitude values of the end surface reflection part of the middle sensor and the stray reflection part of the stator around the rotor to be measured, A5For the radio-frequency input signal Y1The amplitude of the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator,
Figure FDA0002976724230000031
for local oscillator input signal X2The phase of (a) is determined,
Figure FDA0002976724230000032
for the radio-frequency input signal Y1The phase positions of the middle carrier wave reflected signal part, the sensor end surface reflected part and the stator stray reflected part around the rotor to be measured delayed on the transmission cable,
Figure FDA0002976724230000033
for the radio-frequency input signal Y1Wherein the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator delays the phase on the transmission path,
Figure FDA0002976724230000034
for the radio-frequency input signal Y1The middle carrier reflected signal part is subjected to the phase to be detected generated by the change of the rotor stator axial gap;
two paths of orthogonal demodulation signals output by the carrier path mixer are respectively filtered by a second low-pass filter and a third low-pass filter to remove omega frequencyr+ωsAfter the frequency component of (2), the signal Z is obtainedI2And ZQ2Expressed by the following formulae (6) and (7):
ZI2＝SI_IF(t)+SI_tip(t)+SI_le(t) (6)
ZQ2＝SQ_IF(t)+SQ_tip(t)+SQ_le(t) (7)
wherein,
Figure FDA0002976724230000035
is ZI2The carrier reflection signal portion of (1);
Figure FDA0002976724230000036
is ZI2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure FDA0002976724230000037
is ZI2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
Figure FDA0002976724230000038
is ZQ2The carrier reflection signal portion of (1);
Figure FDA0002976724230000039
is ZQ2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure FDA00029767242300000310
is ZQ2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
k is a factor of the amplitude imbalance,
Figure FDA00029767242300000311
is a phase imbalance factor;
in a computer, Z from the transmissionI2And ZI1Performing mixing operation and low-pass filtering to obtain signal VI(d) Is a reaction of ZQ2And ZI1Performing mixing operation and low-pass filtering to obtain signal VQ(d)，VI(d) And VQ(d) Represented by formulas (8) and (9), respectively:
Figure FDA00029767242300000312
Figure FDA0002976724230000041
wherein,
Figure FDA0002976724230000042
Figure FDA0002976724230000043
when the temperature of the working environment is stable and unchanged and the vibration state of the sensor installation environment is stable and unchanged,
Figure FDA0002976724230000044
Atip、Aleare constant and do not vary with rotor-stator axial clearance, and AIFOnly the rotor and stator axial clearance is related, and the inverse proportion relation is formed by the second power of the rotor and stator axial clearance d;
based on the microwave phase ranging principle:
Figure FDA0002976724230000045
wherein ω is1Is the spatial angular frequency of the transmitted microwave radio frequency signal;
obtained from formulae (8), (9), (10):
Figure FDA0002976724230000046
wherein,
Figure FDA0002976724230000047
j is an imaginary unit;
using the frequency spectrum of V (d) signal mainly at main frequency omega1Image frequency-omega1And the DC frequency, the amplitude values at the three frequencies are respectively A (omega) through space distance scanning, namely, rotor and stator axial gap sampling at equal intervals1)、A(-ω1) A (0); the amplitude-phase imbalance correction factor is expressed by equation (12), equation (13), equation (14), and equation (15):
Figure FDA0002976724230000048
Figure FDA0002976724230000049
Figure FDA00029767242300000410
Figure FDA00029767242300000411
establishing a model for inhibiting co-channel interference signals, as shown in formula (17):
Figure FDA00029767242300000412
therefore, the rotor-stator axial gap d after the suppression of the co-channel interference signal is expressed by equation (18):
Figure FDA00029767242300000413
wherein,
Figure FDA00029767242300000414
the constant value is obtained by calibration without changing with the axial clearance of the rotor and the stator to be measured.
4. A microwave-based rotor-stator axial gap on-line measurement method, characterized by being realized by the device of claim 1, wherein: local oscillator input signal Y input by reference path mixer2And a radio frequency input signal X1Represented by formula (1) and formula (2), respectively:
Figure FDA0002976724230000051
Figure FDA0002976724230000052
wherein A is1For the radio-frequency input signal X1Amplitude of (A)6For local oscillator input signal Y2Amplitude of (a), ωsAs reference frequency, ωrIs the carrier frequency and is,
Figure FDA0002976724230000053
for the radio-frequency input signal X1The phase of (a) is determined,
Figure FDA0002976724230000054
for local oscillator input signal Y2The phase of (d);
one path of demodulation signal output by the reference path mixer is filtered by a first low-pass filter to remove the frequency omegar+ωsAfter the frequency component of (2), the signal Z is obtainedI1Represented by formula (3):
Figure FDA0002976724230000055
wherein, ω isIF＝ωs-ωrIs an intermediate frequency;
radio frequency input signal Y input by carrier wave path mixer1And local oscillator input signal X2Represented by formula (4) and formula (5), respectively:
Figure FDA0002976724230000056
Figure FDA0002976724230000057
wherein A is2For local oscillator input signal X2Amplitude of (A)3For the radio-frequency input signal Y1Amplitude of the reflected signal portion of the intermediate carrier, A4For the radio-frequency input signal Y1Amplitude values of the end surface reflection part of the middle sensor and the stray reflection part of the stator around the rotor to be measured, A5For the radio-frequency input signal Y1The amplitude of the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator,
Figure FDA0002976724230000058
for local oscillator input signal X2The phase of (a) is determined,
Figure FDA0002976724230000059
for the radio-frequency input signal Y1The phase positions of the middle carrier wave reflected signal part, the sensor end surface reflected part and the stator stray reflected part around the rotor to be measured delayed on the transmission cable,
Figure FDA00029767242300000510
for the radio-frequency input signal Y1Wherein the radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator delays the phase on the transmission path,
Figure FDA00029767242300000511
for the radio-frequency input signal Y1The middle carrier reflected signal part is subjected to the phase to be detected generated by the change of the rotor stator axial gap;
two paths of orthogonal demodulation signals output by the carrier path mixer are respectively filtered by a second low-pass filter and a third low-pass filter to remove omega frequencyr+ωsAfter the frequency component of (2), the signal Z is obtainedI2And ZQ2Expressed by the following formulae (6) and (7):
ZI2＝SI_IF(t)+SI_tip(t)+SI_le(t) (6)
ZQ2＝SQ_IF(t)+SQ_tip(t)+SQ_le(t) (7)
wherein,
Figure FDA00029767242300000512
is ZI2The carrier reflection signal portion of (1);
Figure FDA0002976724230000061
is ZI2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure FDA0002976724230000062
is ZI2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
Figure FDA0002976724230000063
is ZQ2The carrier reflection signal portion of (1);
Figure FDA0002976724230000064
is ZQ2The end surface reflection part of the sensor and the stray reflection part of the stator around the rotor to be measured;
Figure FDA0002976724230000065
is ZQ2The radio frequency co-frequency crosstalk part caused by low isolation of the radio frequency chip or the circulator in the radio frequency co-frequency crosstalk part;
k is a factor of the amplitude imbalance,
Figure FDA0002976724230000066
is a phase imbalance factor;
in a computer, Z from the transmissionI2And ZI1Performing mixing operation and low-pass filtering to obtain signal VI(d) Will beZQ2And ZI1Performing mixing operation and low-pass filtering to obtain signal VQ(d)，VI(d) And VQ(d) Represented by formulas (8) and (9), respectively:
Figure FDA0002976724230000067
Figure FDA0002976724230000068
wherein,
Figure FDA0002976724230000069
Figure FDA00029767242300000610
when the temperature of the working environment is stable and unchanged and the vibration state of the sensor installation environment is stable and unchanged,
Figure FDA00029767242300000611
Atip、Aleare constant and do not vary with rotor-stator axial clearance, and AIFOnly the rotor and stator axial clearance is related, and the inverse proportion relation is formed by the second power of the rotor and stator axial clearance d;
based on the microwave phase ranging principle:
Figure FDA00029767242300000612
wherein ω is1Is the spatial angular frequency of the transmitted microwave radio frequency signal;
obtained from formulae (8), (9), (10):
Figure FDA00029767242300000613
wherein,
Figure FDA00029767242300000614
j is an imaginary unit;
using the frequency spectrum of V (d) signal mainly at main frequency omega1Image frequency-omega1And the DC frequency, the amplitude values at the three frequencies are respectively A (omega) through space distance scanning, namely, rotor and stator axial gap sampling at equal intervals1)、A(-ω1) A (0); the amplitude-phase imbalance correction factor is expressed by equation (12), equation (13), equation (14), and equation (15):
Figure FDA0002976724230000071
Figure FDA0002976724230000072
Figure FDA0002976724230000073
Figure FDA0002976724230000074
establishing a model for inhibiting co-channel interference signals, as shown in formula (17):
Figure FDA0002976724230000075
therefore, the rotor-stator axial gap d after the suppression of the co-channel interference signal is expressed by equation (18):
Figure FDA0002976724230000076
wherein,
Figure FDA0002976724230000077
the constant value is obtained by calibration without changing with the axial clearance of the rotor and the stator to be measured.
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