Circuit board functional defect positioning method based on dynamic signal feature extraction

Abstract

The application discloses a circuit board function defect positioning method based on dynamic signal feature extraction and belongs to the technical field of electronic equipment detection, which comprises the following steps: S10, acquiring normal signal data of key nodes of a circuit board, wherein the key nodes comprise a power input end, a signal input end and a signal output end; the normal signal data comprises voltage signals and current signals; and a database about the normal signal data is constructed; S20, collecting voltage signals and current signals of the key nodes of the circuit board, analyzing the change law of the voltage signals and the current signals, and comparing the change law with the database. The application can comprehensively, accurately and reliably diagnose faults of the circuit board by comprehensively using signal collection, data analysis and fault diagnosis methods, thereby improving the detection quality and reliability of the function of the circuit board.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic equipment detection, in particular to a circuit board functional defect positioning method based on dynamic signal feature extraction. BACKGROUND

[0002] The circuit board is the core component of modern electronic equipment, and its function reliability directly affects the performance and stability of the equipment. Therefore, it is necessary to detect whether the function of the circuit board is normal.

[0003] For this research, the application number CN202210898704.X provides a signal test system, method, assembled printed circuit board and server. The technical solution includes a signal test fixture, which includes a printed circuit board, and a test fixture test point and an adapter provided on the printed circuit board, and the test fixture test point and the adapter are connected through PCB wiring. The assembled printed circuit board is provided with a test point. The technical solution tests the signal quality through the signal test fixture and the improved test point on the assembled printed circuit board, and improves the signal test quality.

[0004] Another application number CN202110733195.0 provides an intelligent detection system and method for double-layer circuit board. The technical solution includes a transmission module, a controller, a database, a data acquisition module, a data analysis module and an electrical test module. The technical solution can detect the PCB board on the PCB board production line in real time. Through the cooperation of the infrared scanning probe and the camera, not only the PCB board size information can be identified, but also whether there is a circuit break, short circuit, damage, copper surface scratch and copper slag on the PCB board can be judged based on image recognition technology, effectively improving the detection accuracy and efficiency of the PCB board surface quality, and realizing the automatic detection of the PCB board surface defects.

[0005] However, the above technical solution is not sensitive to small short circuits, circuit breaks or component parameter deviations, resulting in poor intelligent diagnosis and positioning ability for faults, making it difficult to accurately detect these potential problems, and easy to cause missed detection, causing faulty circuit boards to flow into subsequent production links or the market, affecting product quality and reliability. SUMMARY

[0006] In view of the above problems existing in the prior art of electronic equipment detection, the present application is proposed.

[0007] Therefore, one of the purposes of the present application is to provide a circuit board function defect positioning method based on dynamic signal feature extraction, which establishes a normal signal benchmark through database comparison, combines real-time feature extraction and dynamic threshold analysis, and realizes accurate positioning and verification of fault points; In this process, not only static parameter comparison is relied on, but also dynamic analysis such as transient response is used to ensure the reliability of fault judgment.

[0008] To solve the above technical problems, the present application provides the following technical solutions:

[0009] The present application provides a circuit board function defect positioning method based on dynamic signal feature extraction, comprising the following steps:

[0010] S10: Obtain normal signal data of key nodes of a circuit board, the key nodes including a power input end, a signal input end and a signal output end; the normal signal data including voltage signals and current signals; and a database about the normal signal data is constructed;

[0011] S20: Collect voltage signals and current signals of the key nodes of the circuit board, analyze the change law of the voltage signals and the current signals, and compare the change law with the database;

[0012] S30: According to the comparison result, mark the collected voltage signals and current signals of the key nodes, including marking the power input end to the signal input end as line I, marking the signal input end to the signal output end as line II, extracting key feature parameters in the line I and the line II, and the key feature parameters including the effective value of the voltage and the current peak value;

[0013] S40: Divide the signal points of the collected voltage signals and current signals in the line I and the line II; obtain the minimum effective value and the minimum current peak value in the effective value of the voltage and the current peak value, and obtain the signal points corresponding to the minimum effective value and the minimum current peak value in the line I and the line II;

[0014] S50: Obtain the positions corresponding to the signal points in the line I and the line II, mark the positions as reference positions; when collecting voltage signals and current signals of the circuit board at a future time, if the collected voltage signals and current signals are lower than the minimum effective value and the minimum current peak value of the reference positions, it is determined that the signal points corresponding to the collected voltage signals and current signals are fault points; otherwise, it is not determined.

[0015] As a preferred scheme of the present application, in the S20, the change law of the voltage signals and the current signals is analyzed, including analyzing in a feature correlation analysis manner, and the feature correlation analysis includes voltage and current correlation analysis and power analysis;

[0016] The voltage and current correlation analysis includes calculating a correlation coefficient between the voltage signal and the current signal,

[0017] The power analysis includes calculating the instantaneous power.

[0018] As a preferred scheme of the present application, wherein: the correlation coefficient between the voltage signal and the current signal is calculated, and is calculated according to the following formula:

[0019] ;

[0020] In the formula, represents the correlation coefficient between the voltage signal and the current signal , and the value range is [-1, 1];

[0021] Equal to 1, which is a positive correlation, that is, the voltage signal increases, and the current signal also increases;

[0022] Equal to -1, which is a negative correlation, that is, among the voltage signal and the current signal, one increases and the other decreases;

[0023] Equal to 0, which is no linear correlation;

[0024] represents the value of the voltage signal at the first sampling point, represents the value of the current signal at the first sampling point, represents the total number of sampling points, represents the mean value of the voltage signal, represents the mean value of the current signal.

[0025] As a preferred scheme of the present application, wherein: the instantaneous power is calculated, and is calculated according to the following formula:

[0026] ;

[0027] In the formula, represents the instantaneous power, which is the power of the circuit board at time , represents the voltage signal, which is the voltage of the circuit board at time , represents the current signal, which is the current of the circuit board at time .

[0028] As a preferred solution of the present application, wherein: the phase difference between the voltage signal and the current signal is also calculated, and is calculated according to the following formula:

[0029] ;

[0030] wherein, the voltage signal and the current signal ; is the Fourier transform of the current signal, representing the complex spectrum of the current signal at frequency ; is the Fourier transform of the voltage signal, representing the complex spectrum of the voltage signal at frequency ;

[0031] represents the phase angle of the complex number, and is used to extract the phase part of the complex number; the steps are as follows:

[0032] performing Fourier transform on the voltage signal and the current signal ; and ;

[0033] calculating the ratio and ; ;

[0034] using the function to extract the phase angle of the complex number ratio, to obtain the phase difference .

[0035] As a preferred solution of the present application, wherein: the number of signal points of the collected voltage signal and current signal divided in the line I and line II is calculated, according to the calculated correlation coefficient and / or phase difference, the average current and average voltage of the signal points in the line I and line II are calculated, the maximum current and maximum voltage corresponding to the average current and average voltage are obtained in the line I and line II, the signal points corresponding to the maximum current and maximum voltage are obtained, and the signal points are marked as fault points.

[0036] As a preferred scheme of the present application, wherein: the fault verification of the fault point comprises analysis of the transient response, the analysis comprises a specific event, the specific event comprises power on, load change and signal mutation; the transient response is obtained when the specific event occurs, the change of the voltage signal and the current signal before and after the specific event is analyzed based on the transient response, the change comprises overshoot of the amplitude of the voltage signal and the current signal, and a safety threshold of the overshoot of the amplitude of the voltage signal and the current signal is preset; the change before and after the specific event comprises overshoot within 1 minute before and after the specific event.

[0037] As a preferred scheme of the present application, wherein: the change of the voltage signal and the current signal before and after the specific event is analyzed based on the transient response, the analysis comprises the following steps:

[0038] The voltage signal and the current signal of the fault point are synchronously collected before and after the specific event;

[0039] The collected voltage signal and current signal are plotted on a time axis to obtain the transient response of the voltage signal and the current signal;

[0040] The key points of the voltage signal and the current signal are marked in the transient response, the key points comprise peak value, valley value and zero-crossing point, and the corresponding time stamp and amplitude are recorded;

[0041] The overshoot is calculated according to the marked key points;

[0042] If the overshoot exceeds the safety threshold, the mark of the signal point as the fault point is maintained, otherwise, the mark is cancelled;

[0043] The overshoot is calculated according to the following formula:

[0044] ;

[0045] In the formula, The overshoot of the current signal is represented by I overshoot, The maximum value of the signal in the amplitude of the current signal is represented by I max, The final steady-state value of the signal in the amplitude of the current signal is represented by I final.

[0046] ;

[0047] In the formula, The overshoot of the voltage signal is represented by V overshoot, The maximum value of the signal in the amplitude of the voltage signal is represented by V max, The final steady-state value of the signal in the amplitude of the voltage signal is represented by V final.

[0048] A computer terminal comprises a processor, an input interface, an output interface and a memory, which are connected with each other, wherein the memory is used for storing a computer program, the computer program comprises program instructions, and the processor is configured to invoke the program instructions for executing the method as described above.

[0049] A computer readable storage medium stores a computer program, the computer program comprises program instructions, and the program instructions, when executed by a processor, cause the processor to execute the method as described above.

[0050] Advantages:

[0051] 1. The application extracts feature parameters and locates fault points in line I (power input end to signal input end) and line II (signal input end to signal output end), thereby improving the efficiency and accuracy of fault troubleshooting.

[0052] 2. The application not only analyzes the basic change rule of voltage and current signals, but also deeply understands the signal characteristics through feature correlation analysis (such as voltage and current correlation analysis and power analysis), and more comprehensively evaluates the working state of the circuit board by calculating the correlation coefficient and instantaneous power between voltage and current, thereby more accurately identifying potential functional defects.

[0053] 3. The application introduces quantitative indicators such as effective value of voltage, current peak value, phase difference, and average current and average voltage calculation based on these indicators, thereby providing objective and quantifiable standards for fault judgment, reducing the subjectivity of human judgment, and improving the accuracy and consistency of fault diagnosis.

[0054] 4. By analyzing the transient response of the fault point, especially when specific events such as power on, load change and signal mutation occur, the transient changes of voltage and current signals are obtained, the overshoot phenomenon is analyzed based on these changes, and a safety threshold is preset to further verify the accuracy of the fault point, thereby enhancing the reliability of fault diagnosis. BRIEF DESCRIPTION OF DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor. Among them:

[0056] Fig. 1 The method flowchart of the embodiment of the application;

[0057] Fig. 2 The flow structure schematic diagram of the embodiment of the present application. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical scheme and advantages of the embodiment of the present application more clear, the technical scheme of the embodiment of the present application will be described clearly and completely below in combination with the drawings of the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, not all the embodiments. Based on the described embodiment of the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0059] Since the prior art is not sensitive to the micro short circuit, open circuit or element parameter deviation and the like faults, the intelligent diagnosis and positioning ability for the faults is weak, the potential problems are difficult to detect accurately, and the faulty circuit board is easy to flow into the subsequent production link or market, which affects the product quality and reliability.

[0060] Based on this, the present application provides a circuit board functional defect positioning method based on dynamic signal feature extraction, which establishes a normal signal reference through database comparison, combines real-time feature extraction and dynamic threshold analysis, realizes accurate positioning and verification of fault points, and the method not only depends on static parameter comparison, but also ensures the reliability of fault judgment through dynamic analysis such as transient response.

[0061] The present application will be further described below in combination with the drawings.

[0062] Reference Figs. 1-2 For an embodiment of the present application, the embodiment provides a circuit board functional defect positioning method based on dynamic signal feature extraction, comprising the following steps:

[0063] S10: Obtain normal signal data of key nodes of the circuit board, the key nodes including power input end, signal input end and signal output end; the normal signal data including voltage signal and current signal; and a database about the normal signal data is constructed;

[0064] In the embodiment, it is necessary to explain that the normal signal data of the key nodes of the circuit board can be obtained from the manufacturer;

[0065] The voltage signal is collected by a high-precision voltage sensor, wherein the sampling frequency of the sensor can be adjusted according to the working frequency of the circuit board and the signal change characteristics, so as to ensure that the voltage and its transient change can be accurately captured;

[0066] The current signal is collected by a current transformer or a Hall sensor at the key nodes;

[0067] S20: Collect the voltage signal and the current signal of the key nodes of the circuit board, analyze the change rule of the voltage signal and the current signal, and compare the change rule with the database;

[0068] S30: According to the comparison result, mark the collected voltage signal and current signal of the key nodes as a line, including marking the power input end to the signal input end as line I, marking the signal input end to the signal output end as line II, extracting key feature parameters in line I and line II, and the key feature parameters include the effective value of the voltage and the current peak value;

[0069] S40: Divide the signal points of the collected voltage signal and current signal in line I and line II; obtain the minimum effective value and the minimum current peak value in the effective value of the voltage and the current peak value, and obtain the signal points corresponding to the minimum effective value and the minimum current peak value in line I and line II;

[0070] In this embodiment, in the real situation, too small current peak value will lead to insufficient performance of the components in the circuit board, such as difficult motor starting, slow signal amplifier response, prolonged capacitor charging time, etc., at the same time, the overall function of the circuit is limited, the transient response speed is reduced, and the dynamic load adaptability is poor;

[0071] In addition, integrated circuits (IC) and other electronic components have a specified minimum operating voltage range, if the effective value of the voltage is too small, lower than the minimum operating voltage of the component, the component will not start or work normally;

[0072] For example, if the actual voltage effective value of a chip with a rated operating voltage of 3.3V is only 2.5V, it may cause the logic circuit inside the chip to fail to flip correctly, the instruction cannot be executed, and finally the chip cannot work normally;

[0073] S50: Obtain the position corresponding to the signal point in line I and line II, mark the position as a reference position; when collecting the voltage signal and the current signal of the circuit board in the future, if the collected voltage signal and the current signal are lower than the minimum effective value and the minimum current peak value of the reference position, it is determined that the signal point corresponding to the collected voltage signal and the current signal is a fault point; otherwise, it is not determined;

[0074] In summary, by collecting the voltage signal and the current signal of the key nodes (power input end, signal input end and signal output end) of the circuit board, and comparing and analyzing with the pre-constructed normal signal database, the function state of the circuit board is determined, the selection of the key nodes is based on the signal transmission path and the function importance, and the normal signal database provides a reference for the subsequent comparison;

[0075] By collecting signals from multiple key nodes, the working status of the circuit board can be comprehensively monitored, avoiding potential problems that may be missed by single signal detection.

[0076] Furthermore, with a database of normal signals as a reference, abnormal signals can be identified more accurately, improving the accuracy and reliability of detection.

[0077] In S20, the variation patterns of voltage and current signals are analyzed, including analysis using feature correlation analysis, which includes voltage-current correlation analysis and power analysis.

[0078] Voltage-current correlation analysis includes calculating the correlation coefficient between voltage and current signals.

[0079] Power analysis includes calculating instantaneous power;

[0080] In this embodiment, correlation analysis can reveal the dependence between voltage and current, which helps to understand the working principle of the circuit and potential failure modes.

[0081] Power analysis can quantify the energy conversion efficiency of a circuit, providing an important reference for circuit design optimization and fault diagnosis.

[0082] The correlation coefficient between the voltage signal and the current signal is calculated using the following formula:

[0083] ;

[0084] In the formula, Indicates voltage signal and current signal The correlation coefficient between them ranges from [-1, 1];

[0085] If the value is 1, it indicates a positive correlation, meaning that as the voltage signal increases, the current signal also increases.

[0086] If the value is -1, it indicates a negative correlation, meaning that if one of the voltage and current signals increases, the other decreases.

[0087] If the value is 0, then there is no linear correlation;

[0088] Indicates voltage signal In the The value of each sampling point, Represents current signal In the The value of each sampling point, This represents the total number of sampling points. This represents the mean value of the voltage signal. represents the mean value of the current signal;

[0089] In this embodiment, the formula quantifies the degree of linear correlation between the two signals by calculating the ratio of the product of their respective standard deviations and the covariance, and the correlation coefficient ranges between [-1, 1], representing different linear correlation cases;

[0090] This provides a quantitative indicator to evaluate the relationship between voltage and current, making the evaluation of this relationship more objective and accurate. Through this quantitative evaluation, the working state of the circuit can be more accurately judged, providing strong support for fault diagnosis and optimal design of the circuit, and helping to discover potential circuit problems, thereby improving the reliability and performance of the circuit.

[0091] The instantaneous power is calculated according to the following formula:

[0092] ;

[0093] In the formula, represents the instantaneous power of the circuit board at time , represents the voltage signal, which is the voltage of the circuit board at time , represents the current signal, which is the current of the circuit board at time ;

[0094] In this embodiment, by multiplying the values of the voltage signal and the current signal at each sampling point, the instantaneous power of the circuit board at that time is calculated, which reflects the energy conversion and consumption of the circuit in a short period of time;

[0095] It can provide accurate energy consumption of the circuit at different time points, which helps to evaluate the dynamic performance and energy efficiency of the circuit. In this way, the energy utilization of the circuit under different working conditions can be more accurately understood, so as to realize real-time monitoring and optimization of the circuit performance, and to discover potential problems that may cause energy conversion efficiency to decline in advance, thereby improving the overall efficiency and reliability of the circuit.

[0096] It also includes calculating the phase difference between the voltage signal and the current signal, which is calculated according to the following formula:

[0097] ;

[0098] In the formula, represents the phase difference between the voltage signal and the current signal , is the Fourier transform of the current signal, representing the complex spectrum of the current signal at frequency , a Fourier transform of the voltage signal, representing the complex spectrum of the voltage signal at frequencies ;

[0099] representing the phase angle of the complex number, for extracting the phase part of the complex number, the steps are as follows:

[0100] performing a Fourier transform on the voltage signal and the current signal , obtaining and ;

[0101] calculating the ratio and ; ;

[0102] extracting the phase angle of the complex ratio using the function, obtaining the phase difference ;

[0103] In this embodiment, the voltage signal and the current signal are Fourier transformed to obtain their spectra, and the phase difference between the two signals is determined by calculating the phase angle of the spectral ratio, which reflects the relative lag or lead relationship of the voltage and current in time and is an important parameter for circuit characteristic analysis;

[0104] The phase difference is one of the key parameters for understanding the behavior of the circuit, especially in AC circuits, which can reflect the inductive or capacitive characteristics of the circuit. By accurately measuring and analyzing the phase difference, the performance of the circuit can be better evaluated, phase abnormalities that may lead to performance degradation or failure of the circuit can be detected in advance, thereby improving the stability and reliability of the circuit, and providing important basis for the design, debugging and maintenance of the circuit.

[0105] The number of signal points of the collected voltage signal and current signal divided in line I and line II is calculated, and the average current and average voltage of the signal points in line I and line II are calculated according to the calculated correlation coefficient and / or phase difference. The maximum current and maximum voltage corresponding to the average current and average voltage are obtained in line I and line II, and the signal points corresponding to the maximum current and maximum voltage are obtained, and the signal points are marked as fault points;

[0106] In this embodiment, in line I and line II, according to the number of signal points, the average current and average voltage calculated by combining the correlation coefficient and the phase difference, the signal points corresponding to the maximum current and the maximum voltage lower than the average value are found, and they are marked as fault points. This method identifies abnormal points based on the statistical characteristics of the signal;

[0107] This statistical-based method can effectively identify abnormal fluctuations in the signal, quickly locate potential fault points, and help maintenance personnel quickly find the problem by marking the fault points, improving maintenance efficiency, reducing maintenance time and cost, and enhancing the reliability and availability of the circuit board.

[0108] The fault point is verified, and the fault verification includes analysis of transient response, and the analysis includes a given specific event, and the specific event includes power-on, load change, and signal mutation; the transient response when the specific event occurs is obtained, the changes of the voltage signal and the current signal before and after the specific event are analyzed based on the transient response, the changes include the overshoot of the amplitude of the voltage signal and the current signal, and a safety threshold of the overshoot of the amplitude of the voltage signal and the current signal is preset; the changes before and after the specific event include the overshoot within 1 minute before the specific event and within 1 minute after the specific event;

[0109] In this embodiment, the changes of the voltage and current signals before and after the occurrence of a specific event (such as power-on, load change, signal mutation, etc.) are analyzed, mainly to observe the transient behavior of these signals when the event is triggered, which can help to judge the stability and response speed of the circuit board;

[0110] Before and after the occurrence of a specific event (such as power-on, load change, signal mutation), the voltage and current signals of the fault point are synchronously collected, the transient response curve is drawn, the key points (peak value, valley value, zero-crossing point) are marked, the overshoot is calculated, and compared with the preset safety threshold to verify the fault point. Transient response analysis can capture the instantaneous changes of signals when a specific event is triggered, which is often a direct manifestation of circuit failure;

[0111] Transient response analysis can capture the instantaneous changes of signals when a specific event is triggered, which is often a direct manifestation of circuit failure, and by comparing with the preset safety threshold, the fault point can be more accurately verified to avoid misjudgment;

[0112] Transient response analysis can evaluate the performance of the circuit under dynamic conditions, help optimize the circuit design, improve its stability and reliability under various working conditions, and ensure the performance of the circuit in actual application.

[0113] Based on the changes of the voltage signal and the current signal before and after the occurrence of a specific event, the analysis steps are as follows:

[0114] Synchronously collect the voltage signal and the current signal of the fault point before and after the occurrence of the specific event;

[0115] Draw the collected voltage signal and current signal on the time axis to obtain the transient response of the voltage signal and the current signal;

[0116] annotating key points of the voltage signal and the current signal in the transient response, the key points including peak values, valley values and zero-crossing points, and recording corresponding time stamps and amplitude values;

[0117] calculating an overshoot according to the annotated key points;

[0118] if the overshoot exceeds a safety threshold, maintaining the label of the signal point as a fault point, otherwise, canceling the label;

[0119] calculating the overshoot according to the following formula:

[0120] ;

[0121] In the formula, denotes the overshoot of the current signal, denotes the maximum value of the signal in the amplitude of the current signal, denotes the final steady-state value of the signal in the amplitude of the current signal;

[0122] ;

[0123] In the formula, denotes the overshoot of the voltage signal, denotes the maximum value of the signal in the amplitude of the voltage signal, denotes the final steady-state value of the signal in the amplitude of the voltage signal;

[0124] It should be noted that by quantifying the degree of overshoot, the transient change amplitude of the signal when a certain event occurs can be more intuitively evaluated. An overshoot exceeding a safety threshold may indicate potential problems in the circuit, such as power quality problems or load switching caused shocks. This quantitative analysis helps to discover and handle overshoot phenomena that may cause circuit damage or performance degradation in a timely manner, thereby improving the reliability and durability of the circuit system.

[0125] A computer terminal comprising a processor, an input interface, an output interface and a memory, the processor, the input interface, the output interface and the memory being connected to each other, wherein the memory is used to store a computer program, the computer program comprising program instructions, the processor being configured to invoke the program instructions for executing the method as above.

[0126] A computer-readable storage medium storing a computer program, the computer program comprising program instructions, the program instructions causing the processor to execute the method as above when executed by the processor.

[0127] In summary, by establishing a normal signal benchmark through database comparison, combining real-time feature extraction and dynamic threshold analysis, accurate positioning and verification of fault points are realized, and the application not only relies on static parameter comparison, but also ensures the reliability of fault judgment through dynamic analysis such as transient response.

[0128] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A circuit board functional defect positioning method based on dynamic signal feature extraction, characterized in that, The method comprises the following steps: S10: obtaining normal signal data of key nodes of a circuit board, the key nodes comprising a power input end, a signal input end and a signal output end; the normal signal data comprising voltage signals and current signals; constructing a database about the normal signal data; S20: collecting voltage signals and current signals of the key nodes of the circuit board, analyzing the change rule of the voltage signals and the current signals, and comparing the change rule with the database; S30: according to the comparison result, marking the collected voltage signals and current signals of the key nodes, comprising marking the power input end to the signal input end as line I, marking the signal input end to the signal output end as line II, extracting key characteristic parameters in the line I and the line II, the key characteristic parameters comprising effective value of voltage and current peak value; S40: dividing signal points of the collected voltage signals and current signals in the line I and the line II; obtaining the minimum effective value and the minimum current peak value in the effective value of voltage and the current peak value, and obtaining the signal points corresponding to the minimum effective value and the minimum current peak value in the line I and the line II; S50: obtaining the positions corresponding to the signal points in the line I and the line II, marking the positions as reference positions; when collecting voltage signals and current signals of the circuit board at a future time, if the collected voltage signals and current signals are lower than the minimum effective value and the minimum current peak value of the reference positions, it is determined that the signal points corresponding to the collected voltage signals and current signals are fault points; otherwise, it is not determined; performing fault verification on the fault points, the fault verification comprising analysis of transient response, the analysis mode comprising giving specific events, the specific events comprising power-on, load change and signal mutation; obtaining transient response when the specific events occur, analyzing the change of voltage signals and current signals before and after the specific events based on the transient response, the change comprising overshoot of amplitude of the voltage signals and the current signals, and presetting a safety threshold of the overshoot of the amplitude of the voltage signals and the current signals; the change before and after the specific events comprises overshoot within 1 minute before and after the specific events; the analysis steps based on the transient response analysis of the voltage signals and the current signals before and after the specific events are as follows: synchronously collecting voltage signals and current signals of the fault points before and after the specific events; plotting the collected voltage signals and current signals on a time axis, obtaining transient response of the voltage signals and the current signals; annotating key points of the voltage signals and the current signals in the transient response, the key points comprising peak value, valley value and zero-crossing point, and recording corresponding time stamp and amplitude; calculating overshoot according to the annotated key points; if the overshoot exceeds the safety threshold, maintaining the marking of the signal points as fault points, otherwise, canceling the marking; calculating the overshoot according to the following formula: ； wherein represents an overshoot of the current signal, represents a maximum value of the signal of the current signal in the amplitude, represents a final steady state value of the signal of the current signal in the amplitude; ； wherein represents an overshoot of the voltage signal, represents a maximum value of the signal in the amplitude of the voltage signal, represents a final steady state value of the signal in the amplitude of the voltage signal.

2. The method for locating a functional defect of a circuit board based on dynamic signal feature extraction according to claim 1, wherein, In the S20, the change rule of the voltage signal and the current signal is analyzed, including analyzing in a characteristic correlation analysis manner, the characteristic correlation analysis including voltage and current correlation analysis and power analysis; The voltage and current correlation analysis includes calculating the correlation coefficient between the voltage signal and the current signal, The power analysis includes calculating the instantaneous power.

3. The method for locating a functional defect of a circuit board based on dynamic signal feature extraction according to claim 2, wherein, The correlation coefficient between the voltage signal and the current signal is calculated, and is calculated according to the following formula: ； In the formula, represents the correlation coefficient between the voltage signal and the current signal , and the value range is [-1, 1]. Equal to 1, then positive correlation, that is, the voltage signal increases, the current signal also increases; equal to -1, then the correlation is negative, i.e. one of the voltage signal and the current signal increases, while the other decreases; Equal to 0, no linear correlation; representing the voltage signal the value at the first sample point, representing the current signal the value at the first sample point, representing the total number of sample points, representing the mean value of the voltage signal, representing the mean value of the current signal.

4. The method for locating a functional defect of a circuit board based on dynamic signal feature extraction according to claim 2, wherein, The instantaneous power is calculated, and is calculated according to the following formula: ； wherein P(t) represents the instantaneous power, the power of the circuit board at time t, V(t) represents the voltage signal, the voltage of the circuit board at time t, I(t) represents the current signal, the current of the circuit board at time t.

5. The method for locating a functional defect of a circuit board based on dynamic signal feature extraction according to claim 4, wherein, The phase difference between the voltage signal and the current signal is also calculated, and is calculated according to the following formula: ； wherein denotes the phase difference between the voltage signal and the current signal , is the Fourier transform of the current signal, denoting the complex spectrum of the current signal at frequency , is the Fourier transform of the voltage signal, denoting the complex spectrum of the voltage signal at frequency . representing the phase angle of a complex number, for extracting the phase part of a complex number; the steps are as follows: performing a Fourier transformation on the voltage signal and the current signal results in and ; Computing and the ratio of ; Using The function extracts the phase angle of the complex ratio, resulting in a phase difference .

6. The method for locating a functional defect of a circuit board based on dynamic signal feature extraction according to claim 5, wherein, The number of signal points of the collected voltage signal and current signal divided in the line I and the line II is calculated, the average current and the average voltage of the signal points in the line I and the line II are calculated according to the calculated correlation coefficient and / or phase difference, the maximum current and the maximum voltage corresponding to the average current and the average voltage in the line I and the line II are obtained, the signal points corresponding to the maximum current and the maximum voltage are obtained, and the signal points are marked as fault points.

7. A computer terminal, characterized in that The processor, the input interface, the output interface and the memory are connected with each other, wherein the memory is used for storing a computer program, the computer program includes program instructions, the processor is configured to call the program instructions, and is used for executing the method in any one of claims 1-6.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, the computer program includes program instructions, and the program instructions make the processor execute the method in any one of claims 1-6 when executed by the processor.

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