A method, system and medium for adaptive correction of sensitivity of eddy current sensor

Abstract

The embodiment of the present invention provides a method, system and medium for adaptive correction of sensitivity of an eddy current sensor, including: S1. Linearly fitting the current self-test excitation response signal to obtain a fitting curve, and calculating the amplitude linearity, dynamic sensitivity and sensor static sensitivity of the fitting curve; S2. Returning n groups of self-test excitation response signals as current self-test excitation signals to S1 to obtain n groups of data; S3. Returning n groups of first switching self-test excitation response signals as current self-test excitation signals to S1 to obtain k×n groups of data; S4. Returning n groups of second switching self-test excitation response signals as current self-test excitation signals to S1 to obtain j×k×n groups of data; S5. Conditionally judging the j×k×n groups of data according to amplitude linearity, dynamic sensitivity and sensor static sensitivity, and correcting the sensitivity of the eddy current sensor according to the conditional judgment result. The embodiment of the present invention solves the technical problems of high sensitivity correction cost and low correction efficiency of the existing eddy current displacement sensor.

Description

Technical Field

[0001] The invention relates to a method, system and medium for adaptively correcting sensitivity of an eddy current sensor. Background Art

[0002] The main pump in a nuclear reactor is the power source for the forced circulation of the primary coolant. Its operating status is highly related to the performance and safety of the nuclear reactor. It is prone to rotor cracks, rotor misalignment, loose components, rotor imbalance, bearing wear and other faults in long-term operation. The control rod drive mechanism is used to support and interchange nuclear fuel assemblies, correctly guide the control rods to start, stop, and adjust the power of the nuclear reaction, and provide secondary safety support for the reactor in the event of an accident. It is prone to roller wear, roller jamming, bearing wear, bearing jamming, loose components and other faults in long-term operation.

[0003] The online monitoring system of the main pump and drive mechanism of a nuclear reactor generally monitors and diagnoses faults of the two devices by collecting acceleration and displacement signals. The eddy current displacement sensor collects the vibration displacement signal of the equipment in a non-contact manner. The reliability and effectiveness of the collected data are crucial to the accuracy of the system fault diagnosis. However, the eddy current displacement sensor is in a harsh environment of high temperature and radiation resistance for a long time. Its sensitivity will change with the changes of environmental factors such as the material of the object being measured, the material of the sensor itself, temperature, and cumulative dose, which will cause data drift and reduce the accuracy of online monitoring of key nuclear reactor equipment.

[0004] At present, nuclear power plant operation and maintenance personnel generally carry portable equipment to the reactor for sensitivity calibration and correction during shutdown and overhaul, which has problems such as high correction cost, high personnel dose, and low correction efficiency. In addition, the same type of high-temperature radiation-resistant eddy current sensors cannot be used interchangeably due to the sensitivity changes caused by the different materials of the measured equipment. Special corrections need to be made for related equipment, resulting in a large amount of repeated redundant work. Summary of the invention

[0005] In order to solve the technical problems of high sensitivity correction cost and low correction efficiency of existing eddy current displacement sensors, the embodiments of the present invention provide an eddy current sensor sensitivity adaptive correction method, system and medium.

[0006] The embodiment of the present invention is achieved through the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a method for adaptively correcting sensitivity of an eddy current sensor, comprising:

[0008] S1. Perform linear fitting on the current self-test excitation response signal to obtain a fitting curve, and calculate the amplitude linearity, dynamic sensitivity and static sensitivity of the fitting curve;

[0009] S2. Return n groups of self-test excitation response signals as current self-test excitation signals to S1 to obtain n groups of data, where n is a positive integer greater than 0;

[0010] S3. Return the n groups of first switching self-test excitation response signals as current self-test excitation signals to S1, and obtain k×n groups of data, where n is an integer greater than 1; wherein the n groups of first switching self-test excitation response signals are obtained by switching k signal excitation frequencies of the excitation signals of each group of self-test excitation response signals that generate the n groups of self-test excitation response signals, and k is a positive integer greater than zero;

[0011] S4. Return the n groups of second switching self-test excitation response signals as current self-test excitation signals to S1, and obtain j×k×n groups of data, where n is an integer greater than 1; wherein the n groups of second switching self-test excitation response signals are obtained by switching j signal excitation amplitudes of the excitation signals of each group of self-test excitation response signals that generate the n groups of first switching self-test excitation response signals, where j is a positive integer greater than zero;

[0012] S5. Perform conditional determination on the j×k×n groups of data according to amplitude linearity, dynamic sensitivity and sensor static sensitivity, and correct the sensitivity of the eddy current sensor according to the conditional determination result.

[0013] Further, it also includes generating a self-test stimulus response signal;

[0014] Generate self-test stimulus response signal; including:

[0015] sending an excitation signal to the eddy current displacement sensor in a correction mode;

[0016] Generate a correction control signal to control the excitation fixture to move at a fixed frequency within a certain displacement range to generate a device vibration signal, so that the eddy current displacement sensor responds to the device vibration signal, and outputs the self-test excitation signal together with the device vibration signal as an output signal, and then filters out the device vibration signal to generate a self-test excitation response signal.

[0017] Furthermore, the condition determination includes: amplitude linearity determination, correlation determination, amplitude change determination and theoretical trend determination.

[0018] Further, S1. performing linear fitting on the current self-test excitation response signal to obtain a fitting curve, and calculating the amplitude linearity, dynamic sensitivity and static sensitivity of the fitting curve; including:

[0019] Calculate the amplitude linearity according to formula (1);

[0020]

[0021] Where: δ is the sensor amplitude linearity, %; is the arithmetic mean of the output signal at the same detection point, V; U M is the output voltage of the sensor at full scale, U 0 The output voltage of the sensor at zero point;

[0022] Calculate the dynamic sensitivity S according to formula (2): d ;

[0023]

[0024] Where: S d is the dynamic sensitivity; U is the peak value of the sensor output at the reference point; D is the vibration displacement at the reference point;

[0025] Calculate the static sensitivity of the sensor according to formula (3);

[0026]

[0027] Where: S is the static sensitivity; i is the number of the selected detection point, U i The voltage output value of the sensor measured at the i-th measurement point, L i is the moving distance of the sensor, and i is a positive integer greater than zero.

[0028] Further, S5. Conditional determination is performed on the j×k×n group of data according to amplitude linearity, dynamic sensitivity and static sensitivity of the sensor, and the sensitivity of the eddy current sensor is corrected according to the conditional determination result; including:

[0029] Compare the amplitude linearity and the amplitude linearity threshold. If the difference between the amplitude linearity and the amplitude linearity threshold is greater than a specified value, it is determined that there is an interference factor. If it is determined that there is an interference factor for multiple consecutive times or more, the sensitivity of the current eddy current sensor is maintained unchanged.

[0030] The sensitivity is corrected according to formula (4): if y<0, the sensitivity of the eddy current sensor is corrected by adjusting the static sensitivity; if y≥0, the sensitivity of the eddy current sensor is corrected by adjusting the dynamic sensitivity;

[0031] y=a[E(R dm )-E(R sm )]+b[D s -D d ] (4)

[0032] Where a and b are the correlation weight and variance weight respectively, R sm is the pseudo-autocorrelation of static sensitivity, R dm is the pseudo-autocorrelation of dynamic sensitivity, E(R sm) is R sm Expectation, E(R dm ) is R dm Expectations, D d is the dynamic sensitivity variance, D S is the static sensitivity variance.

[0033] Furthermore, the static sensitivity pseudo-autocorrelation calculation formula is:

[0034]

[0035] Where: R sm is the pseudo-autocorrelation of static sensitivity, t=1,2,3…X; q=1,2,3…X and t≠q; m=1,2,3…X, XX=j×k;

[0036] The calculation formula of dynamic sensitivity pseudo-autocorrelation is:

[0037]

[0038] Where: R dm It is the pseudo-autocorrelation of dynamic sensitivity, t=1,2,3…X; q=1,2,3…X and t≠q; m=1,2,3…X, X=j×k.

[0039] Further, S5. Conditional determination is performed on the j×k×n group of data according to amplitude linearity, dynamic sensitivity and static sensitivity of the sensor, and the sensitivity of the eddy current sensor is corrected according to the conditional determination result; and further comprising:

[0040] Get the real-time operating temperature T of the eddy current sensor o The operating temperature T recorded in the last test p , if T o >T p And S o <S p or T o <T p And S o >S p , then determine the sensitivity of the eddy current sensor to be recalibrated.

[0041] In a second aspect, an embodiment of the present invention provides an eddy current sensor sensitivity adaptive correction system, comprising:

[0042] A fitting calculation unit, used for performing linear fitting on the current self-test excitation response signal to obtain a fitting curve, and calculating the amplitude linearity, dynamic sensitivity and static sensitivity of the fitting curve;

[0043] A first data generating unit is used to return n groups of self-test excitation response signals as current self-test excitation signals to S1 to obtain n groups of data, where n is a positive integer greater than 0;

[0044] A second data generating unit is used to return n groups of first switching self-test excitation response signals as current self-test excitation signals to S1, and obtain k×n groups of data, where n is an integer greater than 1; wherein the n groups of first switching self-test excitation response signals are obtained by switching k signal excitation frequencies of the excitation signal of each group of self-test excitation response signals that generate the n groups of self-test excitation response signals, and k is a positive integer greater than zero;

[0045] A third data generating unit is used to return n groups of second switching self-test excitation response signals as current self-test excitation signals to S1, and obtain j×k×n groups of data, where n is an integer greater than 1; wherein the n groups of second switching self-test excitation response signals are obtained by switching j signal excitation amplitudes of the excitation signal of each group of self-test excitation response signals that generate the n groups of first switching self-test excitation response signals, and j is a positive integer greater than zero;

[0046] The sensitivity determination and correction unit is used to perform condition determination on the j×k×n groups of data according to amplitude linearity, dynamic sensitivity and sensor static sensitivity, and correct the sensitivity of the eddy current sensor according to the condition determination result.

[0047] Furthermore, it also includes a generating unit; the generating unit is used to send an excitation signal to the eddy current displacement sensor in a correction mode; it is used to generate a correction control signal to control the excitation fixture to move at a fixed frequency within a certain displacement range to generate a device vibration signal, so that the eddy current displacement sensor responds to the device vibration signal, and outputs the self-test excitation signal together with the device vibration signal as an output signal, and then filters out the device vibration signal to generate a self-test excitation response signal.

[0048] In a third aspect, an embodiment of the present invention provides a storage medium, wherein the computer-readable storage medium stores instructions, and when the instructions are executed on a computer, the method for adaptively correcting the sensitivity of an eddy current sensor as described above is executed.

[0049] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0050] An eddy current sensor sensitivity adaptive correction method, system and medium according to an embodiment of the present invention obtain a fitting curve by linearly fitting the current self-test excitation response signal, and calculate the amplitude linearity, dynamic sensitivity and sensor static sensitivity of the fitting curve; perform conditional judgment on the j×k×n groups of data according to the amplitude linearity, dynamic sensitivity and sensor static sensitivity, and correct the sensitivity of the eddy current sensor according to the conditional judgment result, thereby solving the technical problems of high sensitivity correction cost and low correction efficiency of existing eddy current displacement sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1 This is a schematic diagram of the process of the adaptive correction method for the sensitivity of the eddy current sensor.

[0053] Figure 2 This is a schematic diagram of the structure of the eddy current sensor sensitivity adaptive correction system.

[0054] Figure 3 Schematic diagram of the working principle of the adaptive correction system for sensitivity of an eddy current sensor.

[0055] Figure 4 This is the signal processing flow chart of the eddy current pre-adapter.

[0056] Figure 5 The figure is a flow chart of an example of an adaptive correction method for sensitivity of an eddy current sensor. DETAILED DESCRIPTION

[0057] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0058] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to one of ordinary skill in the art that these specific details are not necessarily employed to practice the present invention. In other embodiments, in order to avoid obscuring the present invention, well-known structures, circuits, materials, or methods are not specifically described.

[0059] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. In addition, it will be appreciated by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0060] In the description of the present invention, the directions or positional relationships indicated by terms such as “front”, “rear”, “left”, “right”, “up”, “down”, “vertical”, “horizontal”, “high”, “low”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0061] Example

[0062] In order to solve the technical problems of high sensitivity correction cost and low correction efficiency of the existing eddy current displacement sensor, in the first aspect, the embodiment of the present invention provides an eddy current sensor sensitivity adaptive correction method, referring to Figure 1 As shown, including:

[0063] S1. Perform linear fitting on the current self-test excitation response signal to obtain a fitting curve, and calculate the amplitude linearity, dynamic sensitivity and static sensitivity of the fitting curve;

[0064] S2. Return n groups of self-test excitation response signals as current self-test excitation signals to S1 to obtain n groups of data, where n is a positive integer greater than 0;

[0065] S3. Return the n groups of first switching self-test excitation response signals as current self-test excitation signals to S1, and obtain k×n groups of data, where n is an integer greater than 1; wherein the n groups of first switching self-test excitation response signals are obtained by switching k signal excitation frequencies of the excitation signals of each group of self-test excitation response signals that generate the n groups of self-test excitation response signals, and k is a positive integer greater than zero;

[0066] S4. Return the n groups of second switching self-test excitation response signals as current self-test excitation signals to S1, and obtain j×k×n groups of data, where n is an integer greater than 1; wherein the n groups of second switching self-test excitation response signals are obtained by switching j signal excitation amplitudes of the excitation signals of each group of self-test excitation response signals that generate the n groups of first switching self-test excitation response signals, where j is a positive integer greater than zero;

[0067] S5. Perform conditional determination on the j×k×n groups of data according to amplitude linearity, dynamic sensitivity and sensor static sensitivity, and correct the sensitivity of the eddy current sensor according to the conditional determination result.

[0068] Thus, the embodiment of the present invention obtains a fitting curve by performing linear fitting on the current self-test excitation response signal, and calculates the amplitude linearity, dynamic sensitivity and sensor static sensitivity of the fitting curve; performs conditional judgment on the j×k×n groups of data according to the amplitude linearity, dynamic sensitivity and sensor static sensitivity, and corrects the sensitivity of the eddy current sensor according to the conditional judgment result, thereby solving the technical problems of high sensitivity correction cost and low correction efficiency of the existing eddy current displacement sensor.

[0069] Further, it also includes generating a self-test stimulus response signal;

[0070] Generate self-test stimulus response signal; including:

[0071] sending an excitation signal to the eddy current displacement sensor in a correction mode;

[0072] Generate a correction control signal to control the excitation fixture to move at a fixed frequency within a certain displacement range to generate a device vibration signal, so that the eddy current displacement sensor responds to the device vibration signal, and outputs the self-test excitation signal together with the device vibration signal as an output signal, and then filters out the device vibration signal to generate a self-test excitation response signal.

[0073] Furthermore, the condition determination includes: amplitude linearity determination, correlation determination, amplitude change determination and theoretical trend determination.

[0074] Further, S1. performing linear fitting on the current self-test excitation response signal to obtain a fitting curve, and calculating the amplitude linearity, dynamic sensitivity and static sensitivity of the fitting curve; including:

[0075] Calculate the amplitude linearity according to formula (1);

[0076]

[0077] Where: δ is the sensor amplitude linearity, %; is the arithmetic mean of the output signal at the same detection point, V; U Mis the output voltage of the sensor at full scale, U 0 The output voltage of the sensor at zero point;

[0078] Calculate the dynamic sensitivity S according to formula (2): d ;

[0079]

[0080] Where: S d is the dynamic sensitivity; U is the peak value of the sensor output at the reference point; D is the vibration displacement at the reference point;

[0081] Calculate the static sensitivity of the sensor according to formula (3);

[0082]

[0083] Where: S is the static sensitivity; i is the number of the selected detection point, U i The voltage output value of the sensor measured at the i-th measurement point, L i is the moving distance of the sensor, i is a positive integer greater than zero, is the arithmetic mean of the distance the sensor moves.

[0084] Further, S5. Conditional determination is performed on the j×k×n group of data according to amplitude linearity, dynamic sensitivity and static sensitivity of the sensor, and the sensitivity of the eddy current sensor is corrected according to the conditional determination result; including:

[0085] Compare the amplitude linearity and the amplitude linearity threshold. If the difference between the amplitude linearity and the amplitude linearity threshold is greater than a specified value, it is determined that there is an interference factor. If it is determined that there is an interference factor for multiple consecutive times or more, the sensitivity of the current eddy current sensor is maintained unchanged.

[0086] The sensitivity is corrected according to formula (4): if y<0, the sensitivity of the eddy current sensor is corrected by adjusting the static sensitivity; if y≥0, the sensitivity of the eddy current sensor is corrected by adjusting the dynamic sensitivity;

[0087] y=a[E(R dm )-E(R sm )]+b[D s -D d ] (4)

[0088] Where a and b are the correlation weight and variance weight respectively, R sm is the pseudo-autocorrelation of static sensitivity, R dm is the pseudo-autocorrelation of dynamic sensitivity, E(R sm ) is R sm Expectation, E(Rdm ) is R dm Expectations, D d is the dynamic sensitivity variance, D S is the static sensitivity variance.

[0089] Furthermore, the static sensitivity pseudo-autocorrelation calculation formula is:

[0090]

[0091] Where: R sm is the pseudo-autocorrelation of static sensitivity, t=1,2,3…X; q=1,2,3…X and t≠q; m=1,2,3…X, X=j×k, S Rti represents the tth static sensitivity of the ith measurement point, S Rqi represents the qth static sensitivity of the ith measurement point;

[0092] The calculation formula of dynamic sensitivity pseudo-autocorrelation is:

[0093]

[0094] Where: R dm is the pseudo-autocorrelation of dynamic sensitivity, t=1,2,3…X;q=1,2,3…X and t≠q;m=1,2,3…X,X=j×k,S Dti represents the tth dynamic sensitivity of the ith measurement point, S Dqi represents the qth dynamic sensitivity of the ith measurement point.

[0095] Further, S5. Conditional determination is performed on the j×k×n group of data according to amplitude linearity, dynamic sensitivity and static sensitivity of the sensor, and the sensitivity of the eddy current sensor is corrected according to the conditional determination result; and further comprising:

[0096] Get the real-time operating temperature T of the eddy current sensor o The operating temperature T recorded in the last test p , if T o >T p And S o <S p or T o <T p And S o >S p , then determine the sensitivity of the eddy current sensor to be recalibrated.

[0097] Exemplarily, the eddy current sensor sensitivity adaptive correction method of the embodiment of the present invention refers to Figure 5 As shown, including:

[0098] Step 1: Adjust the system to the sensitivity adaptive correction mode, and drive the excitation fixture to the frequency f by mechanical drive. 0 Displacement 0 The displacement sensor responds to the signal and enters the acquisition system after analog signal processing such as filtering and amplification.

[0099] Step 2: The system performs data linear fitting on the processed signal to obtain a fitting curve, calculates the amplitude linearity and dynamic sensitivity of the curve, and estimates the static sensitivity of the sensor, and repeats the above process until n sets of data are obtained.

[0100] Step 3: Switch a total of k signal excitation frequencies to cover a certain frequency response range, repeat steps 1 and 2, and obtain a total of k×n sets of data.

[0101] Step 4: Switch a total of j signal excitation amplitudes to cover a certain amplitude response range, repeat steps 1, 2, and 3 to obtain a total of j×k×n sets of data.

[0102] Step 5: All data are judged to meet the conditions, including amplitude linearity judgment, correlation judgment, amplitude change judgment, theoretical trend judgment, and finally the sensitivity of adaptive correction is determined.

[0103] The calculation method of the amplitude linearity L in step 2 is to select effective displacement detection points within the full range and record the output value of the detection point, and sequentially measure the output value U of the sensor at each measurement point. i and the moving distance L of the sensor i The above formula is calculated as:

[0104]

[0105] Where: r is the sensor amplitude linearity (%); is the arithmetic mean of the output signal at the same detection point, (V); U M is the output voltage of the sensor at full scale, U 0 The output voltage of the sensor at zero point.

[0106] Among them, the dynamic sensitivity calculation method of step 2 is:

[0107]

[0108] Where: U is the peak value of the sensor output at the reference point; D is the vibration displacement at the reference point.

[0109] Among them, the static sensitivity estimation method of the sensor in step 2 is to remove the zero point and full-scale data in the test data and calculate according to the following formula:

[0110]

[0111] Where: S is the estimated static sensitivity (V / mm); i is the ordinal number of the selected detection point.

[0112] Among them, the amplitude linearity judgment method of step 5 is to judge the threshold value exceeding the limit for the calculated amplitude linearity δ total j×k×n groups of data. If the data exceeds a specific percentage of the threshold, it is determined that there is an interference factor in this adaptive correction, and the data correction needs to be re-iterated. The number of failures is recorded as 1, and data acquisition is restarted. If the number of consecutive failures reaches N times, the sensitivity adaptive correction fails and there is a lot of interference at present. It is recommended to temporarily maintain the sensitivity unchanged and re-correct it after the change time.

[0113] The correlation determination method in step 5 is to calculate the pseudo-autocorrelation and cross-correlation of the static sensitivity and dynamic sensitivity of the sensor respectively.

[0114] The cross-correlation calculation method in step 5 is to calculate the cross-correlation of each group of n static sensitivity and dynamic sensitivity data of j×k groups to obtain the cross-correlation of j×k groups, and calculate the expected cross-correlation E(r m ), and the cross-correlation threshold T r If the comparison is less than the set threshold, it is necessary to iterate again. If it is greater than the set threshold, the calculation continues. The formula for calculating the cross-correlation is as follows:

[0115]

[0116] Where: r m is the cross-correlation, S i is the static sensitivity data, S di It is the dynamic sensitivity data.

[0117] The static sensitivity pseudo-autocorrelation calculation in step 5 refers to the cross-correlation calculation of the static sensitivity of j×k groups of n data in each group, and the first group of n data is defined as S R1 , the n data of the j×kth group are defined as S Rjk , calculate the j×k groups of data according to the cross-correlation formula to get R sm (m=1,2.....jk×(jk-1) / 2), and the static sensitivity pseudo autocorrelation E(R sm ). The cross-correlation calculation formula of static sensitivity pseudo-autocorrelation is as follows:

[0118]

[0119] In the formula: t=1,2...jk, q=1,2...jk and t≠q, m=1,2.....jk×(jk-1) / 2.

[0120] The pseudo-autocorrelation calculation of dynamic sensitivity in step 5 refers to the cross-correlation calculation of n data in each group of j×k groups of dynamic sensitivity, and the first group of n data is defined as S D1 , the n data of the j×kth group are defined as S Djk , calculate the j×k groups of data according to the cross-correlation formula to get R dm (m=1,2.....jk×(jk-1) / 2), and the expected calculation of these data is performed to obtain the dynamic sensitivity pseudo autocorrelation E(R dm ).

[0121]

[0122] In the formula: t=1,2...jk, q=1,2...jk and t≠q, m=1,2.....jk×(jk-1) / 2.

[0123] Among them, the amplitude change determination method in step 5 is to calculate the variance of the calculated static sensitivity amplitude and dynamic sensitivity respectively, and the calculation formula is as follows:

[0124]

[0125] Where: D s is the static sensitivity variance; D d is the dynamic sensitivity variance; E(x) is the expectation of a set of data.

[0126] The static sensitivity pseudo autocorrelation E(R sm ), dynamic sensitivity pseudo-autocorrelation E(R sm ), static sensitivity variance D s , Dynamic sensitivity variance D s Perform static sensitivity and dynamic sensitivity selection branch judgment, the judgment formula is:

[0127] y=a[E(R dm )-E(R sm )]+b[D s -D d ]

[0128] Where a and b are the correlation weight and variance weight respectively, which can be adaptively modified according to the on-site environment.

[0129] If y<0, it means that the characteristics of static sensitivity are more stable and less disturbed, and the final sensitivity is determined through the static sensitivity branch. If y≥0, the dynamic sensitivity branch is selected for the final sensitivity determination.

[0130] The sensitivity of the adaptive correction is finally determined in step 5 as the mean value S obtained by fitting the normal distribution data of one of the static sensitivity or dynamic sensitivity obtained by comparison. o is the final determined adaptive correction sensitivity.

[0131] Among them, the theoretical trend determination method of step 5 is to obtain the real-time working temperature T of the high-temperature radiation-resistant eddy current sensor. o The operating temperature T recorded in the last test p According to the theoretical simulation and actual test results of high temperature radiation resistant eddy current sensor, the sensor sensitivity generally increases with the increase of temperature, that is, the estimated new sensitivity S o , and the sensitivity S of the previous test p The theoretical law must be met. If it is not met, it is necessary to iterate again until the new law is met to ensure the high reliability after the sensitivity adaptive correction.

[0132] Therefore, the embodiment of the present invention realizes adaptive correction of the sensitivity of the high-temperature radiation-resistant eddy-current displacement sensor at the front end of the equipment during reactor operation by allowing technicians to control the monitoring equipment in an electrical plant without irradiation, thereby ensuring to a certain extent that the data measured by the eddy-current displacement sensor is valid and reliable, thereby improving the accuracy of fault diagnosis. Secondly, the same type of eddy-current displacement sensors used by different measured objects no longer need to be recalibrated and can be used interchangeably. In addition, this technology also overcomes to a certain extent the problem of amplitude drift caused by sensitivity changes caused by temperature changes.

[0133] In a second aspect, an embodiment of the present invention provides an eddy current sensor sensitivity adaptive correction system, referring to Figure 2 As shown, including:

[0134] A fitting calculation unit, used for performing linear fitting on the current self-test excitation response signal to obtain a fitting curve, and calculating the amplitude linearity, dynamic sensitivity and static sensitivity of the fitting curve;

[0135] A first data generating unit is used to return n groups of self-test excitation response signals as current self-test excitation signals to S1 to obtain n groups of data, where n is a positive integer greater than 0;

[0136] A second data generating unit is used to return n groups of first switching self-test excitation response signals as current self-test excitation signals to S1, and obtain k×n groups of data, where n is an integer greater than 1; wherein the n groups of first switching self-test excitation response signals are obtained by switching k signal excitation frequencies of the excitation signal of each group of self-test excitation response signals that generate the n groups of self-test excitation response signals, and k is a positive integer greater than zero;

[0137] A third data generating unit is used to return n groups of second switching self-test excitation response signals as current self-test excitation signals to S1, and obtain j×k×n groups of data, where n is an integer greater than 1; wherein the n groups of second switching self-test excitation response signals are obtained by switching j signal excitation amplitudes of the excitation signal of each group of self-test excitation response signals that generate the n groups of first switching self-test excitation response signals, and j is a positive integer greater than zero;

[0138] The sensitivity determination and correction unit is used to perform condition determination on the j×k×n groups of data according to amplitude linearity, dynamic sensitivity and sensor static sensitivity, and correct the sensitivity of the eddy current sensor according to the condition determination result.

[0139] Furthermore, it also includes a generating unit; the generating unit is used to send an excitation signal to the eddy current displacement sensor in a correction mode; it is used to generate a correction control signal to control the excitation fixture to move at a fixed frequency within a certain displacement range to generate a device vibration signal, so that the eddy current displacement sensor responds to the device vibration signal, and outputs the self-test excitation signal together with the device vibration signal as an output signal, and then filters out the device vibration signal to generate a self-test excitation response signal.

[0140] refer to Figure 3 As shown, the correction system for implementing the method of the embodiment of the present invention includes:

[0141] Secondary instrument system, the secondary instrument system includes data processing system, data acquisition system and second-order signal conditioning system; the secondary instrument supplies power to the eddy current pre-adapter. Since the eddy current pre-adapter can work within a certain power supply range and can maintain normal operation under two power supply conditions, the different power supply voltage input can control the eddy current pre-adapter to work in two working conditions: normal monitoring mode and correction mode.

[0142] The signal processing flow chart of eddy current pre-adapter is as follows: Figure 4 As shown, the second-order signal conditioning system provides the working voltage to the eddy current pre-adapter, and the STM32 control chip analyzes the control voltage range, which is divided into two situations: normal monitoring mode and correction mode.

[0143] The STM32 control chip converts the input power into the working voltage required by each module circuit through the built-in power module for each circuit to work. The eddy current pre-adapter first provides the necessary excitation signal for the high-temperature radiation-resistant eddy current displacement sensor through a signal generating circuit composed of a square wave generating circuit, a low-pass filter, and a power amplifier.

[0144] First, the STM32 controls the crystal oscillator to generate a square wave signal. According to the Fourier series expansion of the square wave

[0145]

[0146] Where: E is the signal amplitude; w 0 is the angular frequency of the square wave signal. The expansion includes the first harmonic and multiple harmonics.

[0147] After the crystal oscillator circuit outputs a square wave signal, it is filtered using a low-pass filter. In order to effectively filter out the high-order harmonics in the square wave signal to obtain a pure sine signal, the angular frequency w is obtained. 0 The sine signal can be filtered out by a low-pass filter to remove the second and higher harmonic components in the square wave signal, and the first harmonic can be retained to obtain an angular frequency of w 0 The sine signal contains a DC bias, and the DC component can be filtered out using a capacitor.

[0148] After the excitation signal is generated, it is passed into the detection coil, and then an alternating magnetic field is generated in space and an eddy current effect is generated with the conductor being measured. Therefore, the excitation signal needs a sufficiently large current to drive the coil. The current of the excitation signal generated previously is small and the driving ability is weak, so a current feedback operational amplifier is selected for power amplification.

[0149] The high temperature radiation resistant eddy current displacement sensor responds to the vibration displacement signal and enters the signal extraction module circuit. The signal extraction module circuit includes an AC bridge circuit and a pre-differential amplifier circuit. The purpose is to convert the displacement of the measured conductor into a voltage, and then amplify it through an instrument amplifier. The pre-differential amplifier is used to amplify the small signal output by the AC bridge. It has low distortion and low noise amplification characteristics, and the amplifier has a large bandwidth. When selecting the gain resistor of the amplifier and the resistor and capacitor of the AC bridge, high-precision and low-temperature drift resistors and capacitors are selected to reduce the output drift of the sensor.

[0150] During normal monitoring, the second-order signal conditioning system provides an amplitude of V 0 ±u 0 The working voltage of the STM32 control chip is low, and the signal processed by the signal extraction module circuit directly enters the phase-sensitive detection circuit.

[0151] In correction mode, the second-order signal conditioning system provides an amplitude of V 1 ±u1 The working voltage of the STM32 control chip is high, and the correction signal of the STM32 control chip is high, which drives the motor to run. The excitation fixture can be moved at a fixed frequency f within a certain displacement range s through mechanical drive. The high-temperature radiation-resistant eddy current displacement sensor responds to the equipment vibration signal and the self-test excitation signal at the same time and merges them together. The signal processed by the signal extraction module circuit enters the correction filter. The correction filter is a programmable digital bandpass filter, which can basically filter out the response signal of the equipment vibration and only retain the response signal of the self-test excitation.

[0152] The signals in both working modes enter the phase-sensitive detection circuit. The signal extraction circuit realizes the conversion from displacement to voltage, while the phase-sensitive detection module circuit is used to demodulate the displacement signal, that is, to obtain a DC signal, the size of which is related to the impedance of the detection coil, that is, to the displacement of the conductor being measured. Phase-sensitive detection is realized by a lock-in amplifier, and the signal after phase-sensitive detection processing is output to the second-order signal conditioning system.

[0153] The second-order conditioning system processes the signal by program-controlled amplification, bandpass filtering, etc. and outputs it to the acquisition system to further improve the accuracy of the signal. The acquisition system collects data and uses the sensitivity adaptive correction method to process the signal layer by layer, and finally obtains an estimated and corrected sensitivity.

[0154] In a third aspect, an embodiment of the present invention provides a storage medium, wherein the computer-readable storage medium stores instructions, and when the instructions are executed on a computer, the method for adaptively correcting the sensitivity of an eddy current sensor as described above is executed.

[0155] The embodiment of the present invention can be applied to the adaptive sensitivity correction of eddy current displacement sensors in online monitoring systems of rotating machinery such as nuclear reactor main pumps and drive mechanisms. The correction personnel do not need to enter the nuclear reactor building, but can control the sensor to start the sensitivity correction mode in a dose-free electrical building. In this way, the sensitivity correction can be performed at any time under various working conditions during the operation of the reactor, and the data drift problem caused by the sensitivity change of the eddy current sensor due to the material, temperature, and irradiation of the measured equipment can be solved in time, so as to ensure the accuracy of data monitoring and fault diagnosis, avoid misdiagnosis and missed diagnosis of reactor equipment by the system, so as to maintain the safety of the nuclear reactor, improve the correction efficiency and maintain a low cost. In addition, based on the adaptive sensitivity correction technology of the present invention, the same type of high-temperature radiation-resistant eddy current displacement sensor does not need to be specially corrected for the measurement object, and can be directly applied to the measurement object and then perform data correction and compensation through the adaptive correction method.

[0156] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for adaptively correcting the sensitivity of an eddy current sensor, characterized in that: include: S1. Perform linear fitting on the current self-test excitation response signal to obtain a fitting curve, and calculate the amplitude linearity, dynamic sensitivity and static sensitivity of the fitting curve; S2. Return n groups of self-test excitation response signals as current self-test excitation signals to S1 to obtain n groups of data, where n is a positive integer greater than 0; S3. Return the n groups of first switching self-test excitation response signals as current self-test excitation signals to S1, and obtain k×n groups of data, where n is an integer greater than 1; wherein the n groups of first switching self-test excitation response signals are obtained by switching k signal excitation frequencies of the excitation signals of each group of self-test excitation response signals that generate the n groups of self-test excitation response signals, and k is a positive integer greater than zero; S4. Return the n groups of second switching self-test excitation response signals as current self-test excitation signals to S1, and obtain j×k×n groups of data, where n is an integer greater than 1; wherein the n groups of second switching self-test excitation response signals are obtained by switching j signal excitation amplitudes of the excitation signals of each group of self-test excitation response signals that generate the n groups of first switching self-test excitation response signals, where j is a positive integer greater than zero; S5. Perform conditional determination on the j×k×n groups of data according to amplitude linearity, dynamic sensitivity and sensor static sensitivity, and correct the sensitivity of the eddy current sensor according to the conditional determination result.

2. The method for adaptively correcting the sensitivity of an eddy current sensor as claimed in claim 1, characterized in that: Also included is generating a self-test stimulus response signal; Generate self-test stimulus response signal; including: sending an excitation signal to the eddy current displacement sensor in a correction mode; Generate a correction control signal to control the excitation fixture to move at a fixed frequency within a certain displacement range to generate a device vibration signal, so that the eddy current displacement sensor responds to the device vibration signal, and outputs the self-test excitation signal together with the device vibration signal as an output signal, and then filters out the device vibration signal to generate a self-test excitation response signal.

3. The method for adaptively correcting the sensitivity of an eddy current sensor as claimed in claim 1, characterized in that: The condition determination includes: amplitude linearity determination, correlation determination, amplitude change determination and theoretical trend determination.

4. The method for adaptively correcting the sensitivity of an eddy current sensor as claimed in claim 3, characterized in that: S1. Perform linear fitting on the current self-test excitation response signal to obtain a fitting curve, and calculate the amplitude linearity, dynamic sensitivity and static sensitivity of the fitting curve; include: Calculate the amplitude linearity according to formula (1); Where: δ is the sensor amplitude linearity, %; is the arithmetic mean of the output signal at the same detection point, V; U M is the output voltage of the sensor at full scale, and U0 is the output voltage of the sensor at zero point; Calculate the dynamic sensitivity S according to formula (2): d ; Where: S d is the dynamic sensitivity; U is the peak value of the sensor output at the reference point; D is the vibration displacement at the reference point; Calculate the static sensitivity of the sensor according to formula (3); Where: S is the static sensitivity; i is the number of the selected detection point, U i The voltage output value of the sensor measured at the i-th measurement point, L i is the moving distance of the sensor, i is a positive integer greater than zero, is the arithmetic mean of the distance the sensor moves.

5. The method for adaptively correcting the sensitivity of an eddy current sensor as claimed in claim 3, characterized in that: S5. Conditionally determine the j×k×n group of data according to amplitude linearity, dynamic sensitivity and sensor static sensitivity, and correct the sensitivity of the eddy current sensor according to the conditional determination result; including: Compare the amplitude linearity and the amplitude linearity threshold. If the difference between the amplitude linearity and the amplitude linearity threshold is greater than a specified value, it is determined that there is an interference factor. If it is determined that there is an interference factor for multiple consecutive times or more, the sensitivity of the current eddy current sensor is maintained unchanged. The sensitivity is corrected according to formula (4): if y<0, the sensitivity of the eddy current sensor is corrected by adjusting the static sensitivity; if y≥0, the sensitivity of the eddy current sensor is corrected by adjusting the dynamic sensitivity; y=a[E(R dm )-E(R sm )]+b[D s -D d ] (4) Where a and b are the correlation weight and variance weight respectively, R sm is the pseudo-autocorrelation of static sensitivity, R dm is the pseudo-autocorrelation of dynamic sensitivity, E(R sm ) is R sm Expectation, E(R dm ) is R dm Expectations, D d is the dynamic sensitivity variance, D S is the static sensitivity variance.

6. The method for adaptively correcting the sensitivity of an eddy current sensor as claimed in claim 5, characterized in that: The static sensitivity pseudo-autocorrelation calculation formula is: Where: R sm is the pseudo-autocorrelation of static sensitivity, t=1,2,3…X; q=1,2,3…X and t≠q; m=1,2,3…X, X=j×k, S Rti represents the tth static sensitivity of the ith measurement point, S Rqi represents the qth static sensitivity of the ith measurement point; The calculation formula of dynamic sensitivity pseudo-autocorrelation is: Where: R dm is the pseudo-autocorrelation of dynamic sensitivity, t=1,2,3…X;q=1,2,3…X and t≠q;m=1,2,3…X,X=j×k,S Dti represents the tth dynamic sensitivity of the ith measurement point, S Dqi represents the qth dynamic sensitivity of the ith measurement point.

7. The method for adaptively correcting sensitivity of an eddy current sensor as claimed in claim 6, characterized in that: S5. Conditional determination is performed on the j×k×n group of data according to amplitude linearity, dynamic sensitivity and static sensitivity of the sensor, and the sensitivity of the eddy current sensor is corrected according to the conditional determination result; and further comprising: Get the real-time operating temperature T of the eddy current sensor o The operating temperature T recorded in the last test p , if T o >T p And S o <S p or T o <T p And S o >S p , then determine the sensitivity of the eddy current sensor to be recalibrated.

8. An eddy current sensor sensitivity adaptive correction system, characterized in that: include: A fitting calculation unit, used for performing linear fitting on the current self-test excitation response signal to obtain a fitting curve, and calculating the amplitude linearity, dynamic sensitivity and static sensitivity of the fitting curve; A first data generating unit is used to return n groups of self-test excitation response signals as current self-test excitation signals to S1 to obtain n groups of data, where n is a positive integer greater than 0; A second data generating unit is used to return n groups of first switching self-test excitation response signals as current self-test excitation signals to S1, and obtain k×n groups of data, where n is an integer greater than 1; wherein the n groups of first switching self-test excitation response signals are obtained by switching k signal excitation frequencies of the excitation signal of each group of self-test excitation response signals that generate the n groups of self-test excitation response signals, and k is a positive integer greater than zero; A third data generating unit is used to return n groups of second switching self-test excitation response signals as current self-test excitation signals to S1, and obtain j×k×n groups of data, where n is an integer greater than 1; wherein the n groups of second switching self-test excitation response signals are obtained by switching j signal excitation amplitudes of the excitation signal of each group of self-test excitation response signals that generate the n groups of first switching self-test excitation response signals, and j is a positive integer greater than zero; The sensitivity determination and correction unit is used to perform condition determination on the j×k×n groups of data according to amplitude linearity, dynamic sensitivity and sensor static sensitivity, and correct the sensitivity of the eddy current sensor according to the condition determination result.

9. The eddy current sensor sensitivity adaptive correction system as claimed in claim 8, characterized in that: It also includes a generating unit; the generating unit is used to send an excitation signal to the eddy current displacement sensor in a correction mode; it is used to generate a correction control signal to control the excitation fixture to move at a fixed frequency within a certain displacement range to generate a device vibration signal, so that the eddy current displacement sensor responds to the device vibration signal, and outputs the self-test excitation signal together with the device vibration signal as an output signal, and then filters out the device vibration signal to generate a self-test excitation response signal.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a computer, the method for adaptively correcting the sensitivity of an eddy current sensor as claimed in any one of claims 1 to 7 is executed.

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