CN112485505B - High-frequency alternating current amplitude detection method based on infrared thermal imaging - Google Patents
High-frequency alternating current amplitude detection method based on infrared thermal imaging Download PDFInfo
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Abstract
The invention discloses a high-frequency alternating current amplitude detection method based on infrared thermal imaging, which comprises the steps of fitting an original temperature change curve of each pixel point in an infrared thermal image from left to right and from top to bottom, forming new temperature distribution according to the original positions of the pixel points by using the fitted temperature curve, carrying out mathematical modeling according to a Fourier heat conduction formula, obtaining an analytical solution of the temperature distribution, then obtaining a first-order derivative, obtaining a direct proportion relation between a high-frequency alternating current amplitude and the temperature distribution, and finally carrying out temperature signal reconstruction to obtain an alternating current amplitude.
Description
Technical Field
The invention belongs to the technical field of current detection, and particularly relates to a high-frequency alternating current amplitude detection method based on infrared thermal imaging.
Background
In recent years, in various practical applications such as measurement and control in industrial production, along with improvement of various equipment performances, the significance of accurate measurement of alternating current is becoming more and more important. At present, the detection mode of alternating current mainly comprises a contact type and a non-contact type. The contact detection mode has the advantages of high detection precision, but has the disadvantages that a detection circuit needs to be connected into a circuit to be detected, the two circuits usually have mutual influence, and the position of the detection circuit is difficult to move. The traditional non-contact current detection mode is mainly magnetic detection, and the magnetic detection sensor comprises a current transformer, a Rogowski coil, a Hall current sensor, a reluctance current sensor and the like. These traditional non-contact current detection means highlight a number of insurmountable drawbacks: for the current transformer, the measuring range is limited during measurement, the sensitivity of the current transformer is in direct proportion to the turns of the secondary winding of the current transformer, although the sensitivity can be improved by increasing the turns of the induction coil, the lead perforation area is reduced, the volume of the current transformer is increased, and the coil resistance is greatly influenced by the external environment, so that the measuring accuracy is influenced. The current transformer with the iron core in the magnetic detection mode has the defects of magnetic leakage and poor linearity, and the same electromagnetic current transformer cannot meet the requirements of large-area detection and precision at the same time.
In many conventional non-contact current detection systems, attention is paid to a magnetic detection method and the characteristics of a sensor are studied and improved, and the improvement of a detection means and a detection principle is less considered. Infrared thermal imaging has been widely applied to various industrial scenes as a common nondestructive testing means, and the thermal wave theory contained in infrared thermal imaging has the potential of detecting current density, but has never been used for detecting the leakage current problem of a power system.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a high-frequency alternating current amplitude detection method based on infrared thermal imaging.
In order to achieve the above object, the present invention provides a method for detecting a high frequency alternating current amplitude based on infrared thermal imaging, which is characterized by comprising the following steps:
(1) acquiring an infrared thermal image sequence;
(1.1) setting a detection point x on a metal test piece to be detected with the length of l, then introducing high-frequency alternating current to the metal test piece to be detected under the room temperature condition, and collecting an infrared thermal image video with the detection point x by using a thermal infrared imager;
(1.2) randomly extracting P frames of infrared thermal images according to the acquisition sequence to form an infrared thermal image time sequence TP(x, t), wherein the size of each infrared thermal image frame is M multiplied by N, M, N is the length and width of the infrared thermal image respectively, P represents the number of frames, and x represents the detection point;
(2) reconstructing a temperature signal;
(2.1) in the infrared thermal image of 1-P frames, randomly extracting the temperature value of the pixel point i at the same coordinate position, and then storing the P temperature values in the array X in sequenceiPerforming the following steps;
(2.2) applying the polyfit function to the array XiPerforming exponential fitting on the intermediate temperature value to obtain a smooth temperature-time curve T after the reconstruction of the pixel point ii(x,t)；
Wherein, a0～anThe constant coefficient after fitting, n is a natural number, and t represents time;
(2.3) reconstructing the temperature signal of each pixel point according to the methods from (2.1) to (2.2), and forming a new temperature distribution T (x, T) by the reconstructed temperature signal of each point according to the original position;
(3) constructing a space transient function of temperature distribution and high-frequency current amplitude according to a Fourier heat conduction formula;
wherein k is thermal conductivity, rho is density, c is specific heat capacity, and P iswIs an alternating current heat source;
(4) solving a space transient function;
(4.1) calculating the thermal power generated by the alternating current on the metal test piece to be tested
Setting the alternating current I introduced to the metal test piece to be tested as follows:
I＝Imcos(2πft)
wherein, ImIs the amplitude of the alternating current, f is the frequency of the alternating current;
thus, the alternating current I generates a thermal power of:
wherein R is0Resistance of unit length of metal to be measured;
(4.2) setting initial conditions and boundary conditions
The initial conditions were: t (x,0) ═ F, x is more than 0 and less than l;
the boundary conditions are as follows: t (0, T) ═ T (l, T) ═ E, T > 0;
wherein E is the ambient temperature, F is the initial temperature, T (0, T) represents the temperature of the left end of the metal test piece to be tested, T (l, T) represents the temperature of the right end of the metal test piece to be tested, and T (x,0) represents the initial temperature at the detection point x;
(4.3) solving the space transient function according to the separation variable method
Heating power PwSubstituting the initial condition and the boundary condition into the space transient function in the step (3) to obtain:
then, according to the separation variable method, an analytical solution of the temperature distribution T (x, T) is obtained, which is expressed as:
(5) resolving a first derivative of the temperature distribution T (x, T) to obtain a theoretical square proportional relation between the surface temperature distribution of the metal test piece to be measured and the current amplitude;
(6) and (5) calculating a first derivative of a certain frame in the reconstructed temperature distribution T (x, T) in the actual measurement process based on the square proportional relation obtained in the step (5), so as to obtain the alternating current amplitude I at the detection point x in the framem；
Where ρ is0The resistivity of the metal test piece to be tested is S, and the cross-sectional area of the metal test piece to be tested is S.
The invention aims to realize the following steps:
the invention discloses a high-frequency alternating current amplitude detection method based on infrared thermal imaging, which comprises the steps of fitting an original temperature change curve of each pixel point in an infrared thermal image from left to right and from top to bottom, forming new temperature distribution according to the original positions of the pixel points by using the fitted temperature curve, carrying out mathematical modeling according to a Fourier heat conduction formula, obtaining an analytical solution of the temperature distribution, then obtaining a first-order derivative, obtaining a direct ratio relation between high-frequency alternating current amplitude and the temperature distribution, and finally carrying out temperature signal reconstruction to obtain alternating current amplitude.
Meanwhile, the high-frequency alternating current amplitude detection method based on infrared thermal imaging also has the following beneficial effects:
(1) the method and the device fit the original temperature change curve of each pixel point in the infrared thermal image, and form new temperature distribution according to the original positions of the pixel points by using the fitted temperature curve, so that the influence of discontinuous temperature signals or non-existent derivative due to the existence of abrupt points caused by environmental noise in the infrared thermal imaging process is reduced to the maximum extent;
(2) the invention adopts a mathematical model from the thermal field to the electric field, thus fully utilizing the energy conversion between the thermal field and the electric field;
(3) the method utilizes a signal reconstruction mode to make up the phenomenon that the initial temperature signal cannot be derived due to the existence of discontinuous points, obtains the high-frequency current amplitude distribution condition of the surface of the metal sample by calculating the first-order derivative of the reconstructed temperature distribution, and realizes the measurement of the high-frequency alternating current based on the infrared thermal imaging;
(4) the invention provides an electric heating double-field detection system of a current amplitude detection method, which is a novel non-contact alternating current detection method based on a thermal wave theory and kirchhoff current law, overcomes the defect that a bypass is introduced in the traditional contact current detection method, avoids the influence of a traditional contact measurement circuit on a to-be-detected circuit, improves the condition that the measurement range and the detection precision of a non-contact magnetic detection mode cannot be obtained simultaneously, and has the advantages of large-area detection and high resolution under the condition of keeping the advantage of remote detection of an infrared thermal imaging technology;
(5) the thermal infrared imager is used as a sensor, so that the direct contact with the conductor to be detected is avoided, a special magnetic core material is not needed during detection, the conductor to be detected does not need to pass through the detection coil, and the limitation on the detection position and the area of the conductor to be detected is relaxed;
(6) the invention adopts the envelope method and the Fourier transform combined mode to better extract the temperature response signal, improves the signal-to-noise ratio from the system method and has wide application prospect.
Drawings
FIG. 1 is a flow chart of a high-frequency alternating current amplitude detection method based on infrared thermal imaging according to the present invention;
FIG. 2 is a schematic diagram of a high-frequency AC current amplitude detection method based on infrared thermal imaging;
FIG. 3 is an infrared thermography and inspection point example of a stainless steel sample;
FIG. 4 is a diagram showing an example of a theoretical process of changing the surface temperature of a stainless steel sample;
FIG. 5 is a graph of an example of temperature signal reconstruction;
FIG. 6 is a graph showing an example of the distribution of the high-frequency current amplitude on the surface of a stainless steel sample measured by the present method.
Detailed Description
The following description of the embodiments of the present invention is provided in order to better understand the present invention for those skilled in the art with reference to the accompanying drawings. It is to be expressly noted that in the following description, a detailed description of known functions and designs will be omitted when it may obscure the subject matter of the present invention.
Examples
FIG. 1 is a flow chart of a high-frequency alternating current amplitude detection method based on infrared thermal imaging.
In this embodiment, as shown in fig. 1, the method for detecting a high-frequency alternating current amplitude based on infrared thermal imaging of the present invention includes the following steps:
s1, acquiring an infrared thermal image sequence;
s1.1, in the embodiment, as shown in FIG. 2, a rectangular coil with the diameter of 6.35mm is connected with an eddy current excitation heat source, the eddy current excitation heat source is used for generating high-frequency (383KHz) sinusoidal alternating current, and the electrifying time is 0.1S; then, the long edge of the rectangular coil is placed above a stainless steel sample with artificial defects, the stainless steel sample at room temperature is subjected to high-frequency alternating current electric excitation by using an eddy current excitation source, and finally, an infrared thermal image video at a detection point x in the stainless steel sample with the length of l is acquired by using an infrared thermal imager with the resolution of 320 multiplied by 256 and the sampling frequency of 383Hz, as shown in FIG. 3;
s1.2, randomly extracting P frames of infrared thermal images according to the acquisition sequence to form an infrared thermal image time sequence TP(x, t), wherein the size of each infrared thermal image frame is M multiplied by N, M, N is the length and width of the infrared thermal image respectively, P represents the number of frames, and x represents the detection point;
s2, reconstructing a temperature signal;
s2.1, randomly extracting temperature values of pixel points i at the same coordinate position in the 1-P frame infrared thermal image, and storing the P temperature values in an array X in sequenceiPerforming the following steps;
s2.2, array X is subjected to correlation by utilizing a polyfit functioniPerforming exponential fitting on the temperature value in the step (b), and obtaining a smooth temperature-time curve T after the pixel point i is reconstructed as shown in FIG. 4i(x,t)；
Wherein, a0～anThe constant coefficient after fitting, n is a natural number, and t represents time;
s2.3, reconstructing the temperature signal of each pixel point according to the method of S2.1-S2.2, and forming a new temperature distribution T (x, T) of the reconstructed temperature signal of each point according to the original position;
s3, constructing a space transient function of temperature distribution and high-frequency current amplitude according to a Fourier heat conduction formula;
wherein k is thermal conductivity, rho is density, c is specific heat capacity, and P iswIs an alternating current heat source;
s4, solving a space transient function;
s4.1, calculating the thermal power generated by alternating current on the stainless steel sample
Setting the alternating current I introduced to the stainless steel sample as follows:
I＝Imcos(2πft)
wherein, ImIs the amplitude of the alternating current, f is the frequency of the alternating current;
thus, the alternating current I generates a thermal power of:
wherein R is0Resistance per unit length for stainless steel samples;
s4.2, setting initial conditions and boundary conditions
The initial conditions were: t (x,0) ═ F, x is more than 0 and less than l;
the boundary conditions are as follows: t (0, T) ═ T (l, T) ═ E, T > 0;
wherein E is the ambient temperature, F is the initial temperature, T (0, T) represents the temperature of the left end of the stainless steel sample, T (l, T) represents the temperature of the right end of the stainless steel sample, and T (x,0) represents the initial temperature at the detection point x;
s4.3, solving the space transient function according to the separation variable method
Heating power PwThe initial condition and the boundary condition are substituted into step S3The spatial transient function of (a) yields:
an analytical solution for the temperature distribution T (x, T) is then obtained according to the separation variational method, expressed as:
wherein, TxDenotes the temperature distribution, T, along the stainless steel sample caused by a constant heat sourcetShowing the change in temperature over time, T, due to an alternating heat sourceeRepresents the transient temperature change process from the initial state to the steady state, shown in FIG. 5, TeWill eventually converge to ambient temperature E, n representing a natural number;
in the present embodiment, TxThe temperature profile along the stainless steel sample, caused by the constant heat source, is constant; since the higher the current frequency is, the smaller the amplitude of the temperature fluctuation is, when the current frequency is far greater than the current amplitude, the amplitude of the temperature change is hardly visible, and at this time, the temperature fluctuation term T istIs 0, so according to the separation variance method, the analytical solution approximation to obtain the temperature distribution T (x, T) can be expressed as:
s5, through the analysis, the amplitude of the high-frequency alternating current can be detected only through the first derivative of the temperature distribution at high frequency, and then the square proportional relation between the surface temperature distribution of the metal test piece to be detected and the current amplitude is obtained theoretically;
s6, based on the square proportional relation obtained in the step S5, in the actual measurement process, the square proportional relation is not obtainedAfter each pixel point on the steel test piece is reconstructed according to the temperature signal in the step S2, in consideration of the fact that the diffusion effect of heat is gradually obvious along with the increase of the heating time, in order to eliminate the influence of the diffusion effect of heat on the processing result, the first derivative of the reconstructed temperature distribution sequence T (x, T) at the second frame time is selected, and therefore the alternating current amplitude I at the detection point x is calculatedm；，
Where ρ is0Is the resistivity of the stainless steel sample and S is the cross-sectional area of the stainless steel sample.
Finally, the current amplitude obtained by calculation is calculated according to all pixel points on the stainless steel sample, and a current amplitude distribution diagram as shown in fig. 6 is formed according to the positions of the corresponding pixel points, so that the detection of the high-frequency current amplitude distribution is realized.
Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, and various changes may be made apparent to those skilled in the art as long as they are within the spirit and scope of the present invention as defined and defined by the appended claims, and all matters of the invention which utilize the inventive concepts are protected.
Claims (1)
1. A high-frequency alternating current amplitude detection method based on infrared thermal imaging is characterized by comprising the following steps:
(1) acquiring an infrared thermal image sequence;
(1.1) setting a detection point x on a metal test piece to be detected with the length of l, then introducing high-frequency alternating current to the metal test piece to be detected under the room temperature condition, and collecting an infrared thermal image video with the detection point x by using a thermal infrared imager;
(1.2) randomly extracting P frames of infrared thermal images according to the acquisition sequence to form infrared thermal image timeSequence TP(x, t), wherein the size of each infrared thermal image frame is M multiplied by N, M, N is the length and width of the infrared thermal image respectively, P represents the number of frames, and x represents the detection point;
(2) reconstructing a temperature signal;
(2.1) in the infrared thermal image of 1-P frames, randomly extracting the temperature value of the pixel point i at the same coordinate position, and then storing the P temperature values in the array X in sequenceiPerforming the following steps;
(2.2) applying the polyfit function to the array XiPerforming exponential fitting on the intermediate temperature value to obtain a smooth temperature-time curve T after the reconstruction of the pixel point ii(x，t)；
Wherein, a0～anThe constant coefficient after fitting, n is a natural number, and t represents time;
(2.3) reconstructing the temperature signal of each pixel point according to the methods from (2.1) to (2.2), and forming a new temperature distribution T (x, T) by the reconstructed temperature signal of each point according to the original position;
(3) constructing a space transient function of temperature distribution and high-frequency current amplitude according to a Fourier heat conduction formula;
wherein k is thermal conductivity, rho is density, c is specific heat capacity, and P iswIs an alternating current heat source;
(4) solving a space transient function;
(4.1) calculating the thermal power generated by the alternating current on the metal test piece to be tested
Setting the alternating current I introduced to the metal test piece to be tested as follows:
I＝Imcos(2πft)
wherein, ImIs the amplitude of the alternating current, f is the frequency of the alternating current;
thus, the alternating current I generates a thermal power of:
wherein R is0The resistance is the resistance of the metal test piece to be measured in unit length;
(4.2) setting initial conditions and boundary conditions
The initial conditions were: t (x,0) ═ F, x is more than 0 and less than l;
the boundary conditions are as follows: t (0, T) ═ T (l, T) ═ E, T > 0;
wherein E is the ambient temperature, F is the initial temperature, T (0, T) represents the temperature of the left end of the metal test piece to be tested, T (l, T) represents the temperature of the right end of the metal test piece to be tested, and T (x,0) represents the initial temperature at the detection point x;
(4.3) solving the space transient function according to the separation variable method
Heating power PwSubstituting the initial condition and the boundary condition into the space transient function in the step (3) to obtain:
then, according to the separation variable method, an analytical solution of the temperature distribution T (x, T) is obtained, which is expressed as:
(5) resolving a first derivative of the temperature distribution T (x, T) to obtain a theoretical square proportional relation between the surface temperature distribution of the metal test piece to be measured and the current amplitude;
(6) based on the square proportional relation obtained in the step (5),after the temperature signal in the step (2) is reconstructed, considering that the diffusion effect of heat is gradually obvious along with the increase of the heating time, in order to eliminate the influence of the diffusion effect of heat on the processing result, the first derivative of the reconstructed temperature distribution sequence T (x, T) at the second frame time is selected, and therefore the alternating current amplitude I at the detection point x is calculatedm；
Where ρ is0The resistivity of the metal test piece to be tested is S, and the cross-sectional area of the metal test piece to be tested is S.
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| CN101839938A (en) * | 2010-04-15 | 2010-09-22 | 西安爱邦电磁技术有限责任公司 | Method for testing airplane model lightning current distribution by utilizing thermal infrared imager |
| CN107807270A (en) * | 2017-11-29 | 2018-03-16 | 曲阜师范大学 | A kind of current sensing means and its detection method based on artificial intelligence |
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| CN104036125B (en) * | 2014-05-30 | 2017-05-10 | 河北省电力建设调整试验所 | Method for accurately calculating temperature field in oil-immersed transformer |
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| CN107884614A (en) * | 2017-11-29 | 2018-04-06 | 曲阜师范大学 | A kind of current sensing means and electric current detecting method based on temperature detection |
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