Charger insulation and reverse connection test method and system, storage medium and product

Abstract

The invention provides a charger insulation and reverse connection test method and system, a storage medium and a product, and relates to the technical field of charging piles. And applying a voltage to the input end of the charger based on the screened adaptive initial DC voltage value and a boost strategy. Meanwhile, the internal insulation resistance value is monitored in real time. And according to the resistance change curve and the qualified interval in the test parameters, fine comparison is carried out, and the timestamps, the voltage values, the current values and the resistance values corresponding to abnormal points are quickly called out once the abnormal points are found. A voltage simulation signal generated by reverse connection simulation of an input end and a ground wire is sent to the charger, a complex electrical environment at the reverse connection moment is simulated, an internal protection mechanism of the charger is triggered, whether the charger responds normally or not is monitored, if yes, signal sending is stopped in time, and overload damage is avoided. Insulation test and reverse connection test processes are integrated, the defects of function splitting and complicated operation of related technologies are avoided, and the problems of high operation difficulty and high cost are solved.

Description

Technical Field

[0001] The present application relates to the technical field of charging piles, and in particular to a charger insulation and reverse connection testing method, system, storage medium and product. Background Art

[0002] In today's booming electric vehicle industry, chargers are key energy supply components, and their safety is as important as the cornerstone. As the number of electric vehicles continues to rise, the use scenarios of chargers are becoming more and more complex and diverse, from open-air parking lots exposed to high temperatures to underground garages with low temperatures and humidity, as well as bus charging stations with complex electromagnetic environments, all of which pose severe challenges to the stable operation of chargers. Once the charger has insulation failure or reverse connection problems, it is very easy to cause serious safety accidents such as leakage, short circuit, and even fire, which not only endangers the vehicle and surrounding facilities, but may also threaten the safety of people's lives. Therefore, the insulation and reverse connection test of the charger has become the core link to ensure safety.

[0003] At present, the common method for insulation testing is to use an insulation resistance tester. According to the established process, technicians regularly connect the tester to the specific port of the charger to obtain insulation resistance readings; or they use high voltage to simulate extreme working conditions to test the tolerance of insulation materials, and judge the insulation performance by observing whether breakdown occurs. In terms of reverse connection testing, a protection system is often built with the help of diodes, relays or intelligent control chips. Diodes use unidirectional conductivity to block reverse current, relays switch circuit connections through electromagnetic control, and intelligent control chips rely on built-in programs to accurately monitor and control the current flow to prevent reverse connection from damaging the charger.

[0004] Related technologies When conducting insulation tests, the traditional manual operation mode relies on the experience of professionals, has complicated steps, is time-consuming, and is prone to errors due to human negligence. Although automatic testing has partially solved the efficiency problem, it is relatively expensive, and single-function test instruments put users in a dilemma between cost and ease of operation.

[0005] Therefore, the relevant technology has technical problems of high difficulty in operation and high cost. Summary of the invention

[0006] The present application provides a charger insulation and reverse connection test method, system, storage medium and product, which are used to solve the problems of difficult operation and high cost.

[0007] In the first aspect, the present application provides a charger insulation and reverse connection test method, including: filtering out test parameters from a built-in adaptation database according to input charger model information; applying a DC voltage to the charger input terminal according to the adapted initial DC voltage value and boost strategy in the test parameters, and monitoring the internal insulation resistance value of the charger at the same time; removing abnormal fluctuation points of the resistance value, and fitting a resistance change curve; comparing the resistance change curve with a qualified interval in the test parameters; in the case where there are abnormal points that cause the comparison to be unqualified, calling out the timestamp corresponding to the abnormal point and the corresponding voltage, current, and resistance value; sending a voltage simulation signal to the charger, the voltage simulation signal being obtained when the charger input terminal is reversely connected to the ground wire; monitoring whether the internal protection mechanism of the charger is triggered; and stopping sending the voltage simulation signal when the internal protection mechanism is triggered.

[0008] By adopting the above technical solution, the test parameters are screened from the built-in adaptation database according to the charger model information. Voltage is applied to the charger input terminal based on the screened adaptation initial DC voltage value and the boost strategy. At the same time, the internal insulation resistance value is monitored in real time, and the two work together to achieve instant control of the insulation performance of the charger in the initial state of power-on. Remove the abnormal fluctuation points of the resistance value and fit the resistance change curve, and then carefully compare the resistance change curve with the qualified interval in the test parameters. Once an abnormality is found, quickly call out the timestamp and voltage, current, and resistance values ​​corresponding to the abnormal point to provide clues for troubleshooting. Send a voltage simulation signal generated by the reverse connection simulation of the input terminal and the ground wire to the charger, simulate the complex electrical environment at the moment of reverse connection, trigger the internal protection mechanism of the charger, monitor whether it responds normally, and stop sending signals in time if triggered to avoid overload damage. In this way, the insulation test and reverse connection test processes are integrated to efficiently realize the comprehensive test of the insulation and reverse connection performance of the charger, avoid the disadvantages of the separation of related technical functions and complicated operations, and solve the problems of difficult operation and high cost.

[0009] In combination with some embodiments of the first aspect, in some embodiments, before the step of sending a voltage simulation signal to the charger, the method also includes: collecting harmonic data groups generated by chargers of different models under the same test procedure framework; determining the harmonic frequency value range, the upper and lower limits of the amplitude at different frequencies, and the allowable phase deviation range according to the harmonic data groups; selecting harmonic frequency, amplitude and phase parameters from the harmonic frequency value range, the upper and lower limits of the amplitude at different frequencies, and the allowable phase deviation range, and superimposing them on the fundamental wave obtained by the circuit simulation process to obtain a superimposed waveform; performing digital-to-analog conversion on the superimposed waveform to obtain a voltage simulation signal.

[0010] By adopting the above technical solution, we first collect harmonic data groups of chargers of different models under the same test procedure framework. These data, which are derived from reality and have been sorted, provide a basis for subsequent simulation. Determine the value range of key parameters based on the harmonic data group, then select appropriate parameters to superimpose on the fundamental wave obtained by the circuit simulation process, and finally convert them into voltage simulation signals. On the one hand, this data-driven simulation signal generation method avoids the problem of data storage and processing overload caused by the pursuit of full coverage of real data, ensuring the smooth operation of the test system; on the other hand, it accurately simulates the complex reverse electrical environment containing rich harmonic interference and spike pulses, solving the dilemma of extreme reverse connection conditions that are difficult to reproduce and inaccurate simulation, and effectively improves the credibility of the test results.

[0011] In combination with some embodiments of the first aspect, in some embodiments, before the step of superimposing on the fundamental wave obtained by the circuit simulation process to obtain the superimposed waveform, the method also includes: recording the circuit architecture into the analog circuit; changing the circuit architecture in the analog circuit so that the input end is reversely connected to the ground wire; starting the analog circuit simulation program, recording the voltage waveform when the current changes from steady state to jump, and obtaining the fundamental wave.

[0012] By adopting the above technical solution, the actual circuit architecture is recorded into the simulation circuit and its input end is reversed to the ground wire, and then the simulation program is started to record the voltage waveform under specific current changes to obtain the fundamental wave. This process accurately restores the changes in electrical characteristics caused by the charging and discharging of the line inductance and capacitance at the moment of reverse connection, providing the most realistic fundamental wave blueprint for subsequent complex simulations such as superimposed harmonics.

[0013] In combination with some embodiments of the first aspect, in some embodiments, after the step of applying a DC voltage to the input terminal of the charger according to the adapted initial DC voltage value and the boost strategy in the test parameters and monitoring the internal insulation resistance value of the charger, the method also includes: scanning the charger within a preset frequency range to obtain spectrum information of electromagnetic interference around the charger; marking the interference intensity level of each frequency band according to the spectrum information; taking the resistance value obtained during the frequency band range with the lowest interference intensity level as the benchmark data; and using the benchmark data to calibrate the resistance value obtained during other frequency band ranges, where the other frequency band ranges are the frequency band ranges except the frequency band range with the lowest interference intensity level.

[0014] By adopting the above technical solution, the charger is scanned in the preset frequency range to obtain the electromagnetic interference spectrum information, accurately mark the interference intensity level of each frequency band, find the frequency band with the lowest interference intensity, and use the resistance value in this period as the benchmark data to calibrate the resistance values ​​of other frequency bands. In the environment of large charging stations where multiple charging piles are running at the same time, the electromagnetic radiation interference of adjacent charging piles is effectively resisted. With reliable benchmark data as a reference, the resistance measurement value distorted by the superposition of interference such as high-frequency harmonics is calibrated to ensure that the fitting accuracy of the insulation resistance change curve is not affected, maintain the authenticity of the reverse connection simulation signal, so that the test data can truthfully reflect the status of the charger, improve the test accuracy, and provide a basis for subsequent judgment of the insulation and reverse connection performance of the charger.

[0015] In combination with some embodiments of the first aspect, in some embodiments, the step of using benchmark data to calibrate the resistance value obtained during the frequency band range except the frequency band range with the lowest interference intensity level specifically includes: determining the resistance compensation coefficient corresponding to other frequency band ranges; multiplying the resistance value obtained during other frequency band ranges by the corresponding resistance compensation coefficient.

[0016] By adopting the above technical solution, the resistance compensation coefficient corresponding to other frequency bands is determined, and then the resistance value obtained in the frequency band is multiplied by the compensation coefficient. This allows the resistance measurement data to return to the right track, avoids the accumulation of measurement errors caused by interference, and ensures the accuracy of insulation resistance measurement.

[0017] In combination with some embodiments of the first aspect, in some embodiments, the step of determining the resistance compensation coefficient corresponding to other frequency bands specifically includes: the resistance compensation coefficient is the product of the interference ratio, the inverse of the interference frequency band bandwidth, and the exponent of the rate of change plus 1; the interference ratio is the ratio of the peak interference intensity to the average interference intensity, and the exponent of the rate of change is the product of the interference intensity change rate multiplied by the interference intensity coefficient and the exponent of the natural constant.

[0018] By adopting the above technical solution, the resistance compensation coefficient is composed of the product of the interference ratio, the inverse of the interference frequency band bandwidth, and the rate of change index plus 1, where the interference ratio reflects the fluctuation characteristics of the interference intensity, the inverse of the interference frequency band bandwidth reflects the concentration of the interference energy, and the rate of change index covers the dynamic change weight of the interference. Such a finely constructed compensation coefficient comprehensively considers the multi-dimensional characteristics of electromagnetic interference and quantifies the impact of complex and changeable electromagnetic interference on the resistance value into a precise coefficient. When facing electromagnetic interference of different intensities, frequency bands, and dynamic changes, the resistance measurement value can be accurately corrected by this coefficient, and the real resistance without interference can be restored to the greatest extent, making the test data stable and reliable.

[0019] In combination with some embodiments of the first aspect, in some embodiments, the step of removing abnormal fluctuation points of the resistance value specifically includes: determining the resistance value whose change rate between adjacent resistance values ​​is higher than a threshold as an abnormal fluctuation point, and removing the abnormal fluctuation point.

[0020] By adopting the above technical solution, these abnormal fluctuation points can be reasonably identified and interference data can be timely screened out, making the subsequent fitted resistance change curve smoother and truly reflecting the resistance change trend, thus avoiding the misjudgment of the insulation performance of the charger caused by the mixing of abnormal data.

[0021] In a second aspect, the present application provides a charger insulation and reverse connection test system, which includes: one or more processors and a memory; the memory is coupled to the one or more processors, the memory is used to store computer program code, the computer program code includes computer instructions, and one or more processors call the computer instructions to enable the charger insulation and reverse connection test system to perform the method described in the first aspect and any possible implementation method of the first aspect.

[0022] In a third aspect, the present application provides a computer program product comprising instructions, which, when the computer program product is run on a charger insulation and reverse connection test system, enables the charger insulation and reverse connection test system to perform the method described in the first aspect and any possible implementation of the first aspect.

[0023] In a fourth aspect, the present application provides a computer-readable storage medium comprising instructions, which, when executed on a charger insulation and reverse connection test system, causes the charger insulation and reverse connection test system to execute the method described in the first aspect and any possible implementation of the first aspect.

[0024] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: 1. Filter test parameters from the built-in adaptation database based on the charger model information. Apply voltage to the charger input terminal based on the selected adaptation initial DC voltage value and boost strategy. At the same time, monitor the internal insulation resistance value in real time, and the two work together to achieve instant control of the insulation performance of the charger in the initial state of power-on. Remove the abnormal fluctuation points of the resistance value and fit the resistance change curve, and then carefully compare the resistance change curve with the qualified interval in the test parameters. Once an abnormality is found, quickly call out the timestamp and voltage, current, and resistance values ​​corresponding to the abnormal point to provide clues for troubleshooting. Send a voltage simulation signal generated by the reverse connection simulation of the input terminal and the ground wire to the charger, simulate the complex electrical environment at the moment of reverse connection, trigger the internal protection mechanism of the charger, monitor whether it responds normally, and stop sending signals in time if triggered to avoid overload damage. In this way, the insulation test and reverse connection test processes are integrated to efficiently realize the comprehensive test of the insulation and reverse connection performance of the charger, avoid the disadvantages of the separation of related technical functions and complicated operations, and solve the problems of difficult operation and high cost.

[0025] 2. First, collect the harmonic data groups of different types of chargers under the same test procedure framework. These data, which are derived from actual and sorted data, provide a basis for subsequent simulation. Determine the value range of key parameters based on the harmonic data group, then select appropriate parameters to superimpose on the fundamental wave obtained by the circuit simulation process, and finally convert them into voltage simulation signals. On the one hand, this data-driven simulation signal generation method avoids the problem of data storage and processing overload caused by the pursuit of full coverage of real data, ensuring the smooth operation of the test system; on the other hand, it accurately simulates the complex reverse electrical environment containing rich harmonic interference and spike pulses, solving the dilemma of extreme reverse connection conditions that are difficult to reproduce and inaccurate simulation, and effectively improves the credibility of the test results.

[0026] 3. Scan the charger in the preset frequency range to obtain the electromagnetic interference spectrum information, accurately mark the interference intensity level of each frequency band, find the frequency band with the lowest interference intensity, and use the resistance value in this period as the benchmark data to calibrate the resistance values ​​of other frequency bands. In the environment of large charging stations where multiple charging piles are running at the same time, the electromagnetic radiation interference of adjacent charging piles is effectively resisted. With reliable benchmark data as a reference, calibrate the resistance measurement value that is distorted due to the superposition of interference such as high-frequency harmonics, ensure that the fitting accuracy of the insulation resistance change curve is not affected, maintain the authenticity of the reverse connection simulation signal, so that the test data truthfully reflects the status of the charger, improves the test accuracy, and provides a basis for subsequent judgment of the charger insulation and reverse connection performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of a charger insulation and reverse connection test method in an embodiment of the present application; Figure 2 is another flow chart of the charger insulation and reverse connection test method in the embodiment of the present application; Figure 3 is another flow chart of the charger insulation and reverse connection test method in the embodiment of the present application; Figure 4 It is an exemplary hardware structure diagram of the charger insulation and reverse connection test system in the embodiment of the present application. DETAILED DESCRIPTION

[0028] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to be used as limitations to the present application. As used in the specification and appended claims of the present application, the singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include plural expressions, unless there is a clear indication to the contrary in the context. It should also be understood that the term "and / or" used in the present application refers to and includes any or all possible combinations of one or more listed items.

[0029] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0030] See also Figure 1 , Figure 1 It is a flow chart of a charger insulation and reverse connection test method in an embodiment of the present application; A charger insulation and reverse connection test method, system, storage medium and product, including: S101, filtering out test parameters from a built-in adaptation database according to input charger model information; The built-in adaptation database refers to an electronic information library pre-stored inside the test system, covering a large number of detailed technical data of different types of chargers and corresponding test adaptation solutions. It contains key information such as the rated voltage, rated current, insulation material characteristics, and internal circuit architecture of each type of charger, providing a data foundation for accurate testing. The test parameters are key values ​​for insulation and reverse connection tests for specific charger models selected from the database, including initial test voltage, current upper limit, resistance qualified range, etc.

[0031] In some embodiments, when a charger of an unknown model needs to be tested, the tester first accurately enters the charger model information into the test system. The system then starts a search program to quickly match all test parameters corresponding to the model in the built-in adaptation database.

[0032] S102, applying a DC voltage to the input terminal of the charger according to the adapted initial DC voltage value and the boost strategy in the test parameters, while monitoring the insulation resistance value inside the charger; The boost strategy is a voltage boost scheme designed according to the charger startup process and power demand changes, covering the boost phase division, voltage increments in each phase, time intervals and other elements. It is divided into three phases: pre-start, slow rise, and stable. The pre-start phase maintains a low voltage to allow the charger's internal circuit to preheat. The slow rise phase increases the voltage at a certain rate to adapt to the gradually increasing power demand. The stable phase maintains a constant voltage to ensure stable power supply.

[0033] In some embodiments, the test system converts the adapted initial DC voltage value into a digital instruction and sends it to the programmable DC power supply. The power supply outputs a precise voltage to the charger input terminal according to the instruction. The voltage sensor is used to provide real-time feedback on the actual voltage at the charger input terminal. The insulation resistance monitor is started synchronously, and the resistance measurement data is transmitted to the system in real time for storage and analysis through a multi-channel data acquisition card.

[0034] In some embodiments, the measuring instrument uses a four-wire connection method, two wires provide a constant test current, and the current flows through the insulation part inside the charger. Due to different insulation conditions, the resistance to the current is different, which will produce a corresponding voltage drop. The other two wires measure the voltage drop value, and then calculate according to Ohm's law to obtain the insulation resistance value.

[0035] S103, removing abnormal fluctuation points of the resistance value and fitting a resistance variation curve; Among them, the abnormal fluctuation point of the resistance value refers to the measurement data point where the resistance value deviates from the normal change trend, suddenly increases or decreases due to factors such as electromagnetic interference, poor line contact, and instantaneous component failure during the operation or testing of the charger. Fitting the resistance change curve refers to using mathematical algorithms (such as the least squares method, spline interpolation method, etc.) to process a series of resistance measurement values ​​after removing the abnormal fluctuation points, and construct a function curve that can smoothly and accurately reflect the change trend of the charger insulation resistance over time or working conditions, which is convenient for subsequent analysis and judgment.

[0036] In some embodiments, a dynamic threshold judgment algorithm is used to identify abnormal fluctuation points of the resistance value, and once the resistance value exceeds the threshold range, it is judged as abnormal. Subsequently, the remaining data after removing the abnormal points is curve-fitted using the cubic spline interpolation method to generate a resistance change curve.

[0037] In some embodiments, step S103 specifically includes: S1031, determining the resistance value whose change rate between adjacent resistance values ​​is higher than a threshold as an abnormal fluctuation point, and removing the abnormal fluctuation point.

[0038] In some embodiments, after the insulation resistance monitoring data of the charger has accumulated to a certain extent (such as a preset number of continuous resistance values ​​have been collected), the resistance value data file is imported. The software first calculates the rate of change between adjacent resistance values ​​according to a predetermined algorithm. In this process, for each pair of adjacent resistance values, it accurately subtracts and divides by the front resistance value, and then multiplies by 100% to obtain the rate of change value. These values ​​are arranged in a new column in sequence to correspond to the original resistance value data. Next, the software automatically compares each value in the rate of change column with the preset threshold value. Once a value greater than the threshold value is found, the corresponding resistance value is immediately located in the original resistance value column and marked as an abnormal fluctuation point, usually highlighted in a special color (such as red) or with a note mark next to it.

[0039] It can be seen that by setting reasonable identification of these abnormal fluctuation points and timely filtering out interference data, the subsequent fitted resistance change curve can be smoother and truly reflect the resistance change trend, thus avoiding the misjudgment of the charger insulation performance caused by the mixing of abnormal data.

[0040] S104, comparing the resistance change curve with the qualified interval in the test parameters; In some embodiments, after completing the resistance change curve fitting, the system immediately retrieves the qualified interval value in the test parameters, and visually compares the curve with the qualified interval, and uses different colors to mark the position relationship between the curve and the interval on the display screen, such as green if the curve is within the qualified interval, and red if it is partially or completely outside the qualified interval. At the same time, numerical calculation methods are used to calculate quantitative indicators such as the intersection of the curve and the interval boundary and the area where the curve exceeds the interval, to further assist in judging the degree of deviation of insulation performance.

[0041] S105. In the case where there is an abnormal point causing the comparison to be unqualified, calling out the timestamp corresponding to the abnormal point and the corresponding voltage, current, and resistance values; The abnormal points refer to the points outside the qualified range found by comparing the resistance change curve with the qualified range in the test parameters in step S104. These points represent that the insulation resistance value of the charger during the test deviates from the normal range, indicating that there may be insulation hazards or other electrical problems.

[0042] In some embodiments, when step S104 is compared and found to have an abnormal point (i.e., the resistance change curve partially or completely exceeds the qualified interval), the system automatically and quickly traces back a large amount of stored test data based on the timestamp index. Using the precise time corresponding to the abnormal point as a clue, the voltage, current, and resistance values ​​at the same time are quickly located and retrieved from the massive data, and then these data are organized into a clear and detailed table and displayed on the display screen. At the same time, in order to more intuitively present the change trend before and after the abnormality, the system also marks the resistance change trend chart for a period of time before and after the abnormal point appears (such as 5 seconds before and after). By viewing this information, the technician can determine whether the resistance abnormality is caused by factors such as instantaneous voltage shock, current instability, or short-term abnormalities in the internal components of the charger.

[0043] It should be noted that once such abnormal points exist, it indicates that the charger is likely to have insulation risks, such as aging and moisture of the insulation material, or local short circuit in the internal circuit causing degradation of insulation performance, which in turn threatens the safe and stable operation of the charger and the reliability of the charging process.

[0044] S106, sending a voltage simulation signal to the charger, where the voltage simulation signal is obtained when the charger input terminal is reversely connected to the ground wire; Among them, the voltage simulation signal is a complex voltage waveform signal artificially simulated when the charger input terminal is reversely connected to the ground wire, which is used to detect the response ability of the charger's internal protection mechanism under reverse connection faults. It covers the characteristics of voltage amplitude mutation, frequency change, harmonic components, etc. that may occur at the moment of reverse connection, and can accurately reproduce the electrical environment under the real reverse connection scenario. Reverse connection between the charger input terminal and the ground wire means that the input terminal originally connected to the positive pole of the external power supply is mistakenly connected to the ground wire, or vice versa. This incorrect connection will cause a series of problems such as abnormal current and voltage shock, which seriously threatens the safety of the charger. Therefore, it is necessary to test the protection mechanism by simulating this scenario.

[0045] In some specific embodiments, voltage and current waveform data of different models of chargers in actual reverse connection accidents are collected to establish a reverse connection fault waveform database; based on the model of the charger to be tested, similar waveforms are selected from the database as a basis, and waveform editing software is used to perform fine-tuning (such as adjusting harmonic content and amplitude ratio) to generate a voltage simulation signal; the generated signal is amplified to a suitable power through a power amplifier, and then coupled to the charger input terminal through an isolation transformer to avoid interference with the test system, which is not limited here.

[0046] In some specific embodiments, a reverse connection circuit model of a charger is constructed using circuit simulation software, and different parameters (such as line inductance, capacitance, and power supply internal resistance) are set to simulate various reverse connection conditions; voltage waveform data is extracted from the simulation results, and an analog voltage signal is obtained through digital-to-analog conversion; a feedback control system is used to monitor the quality of the signal applied to the charger input terminal in real time. If the signal is distorted or the power is insufficient, the simulation parameters or amplifier gain are adjusted in time to ensure the simulation effect, which is not limited here.

[0047] S107, monitoring whether the internal protection mechanism of the charger is triggered; Among them, the internal protection mechanism of the charger refers to a series of hardware circuits and software algorithm combinations built into the charger to prevent electrical failures and ensure its own safe operation, including overcurrent protection circuits, overvoltage protection circuits, reverse connection protection circuits, leakage protection circuits, etc., which will automatically trigger when sensing abnormal electrical signals (such as overcurrent, overvoltage, reverse connection, leakage, etc.), cut off the circuit or take other protective measures to prevent damage to the charger. Monitoring whether the internal protection mechanism of the charger is triggered is to use various sensors and monitoring methods to determine in real time whether these protection mechanisms are normally started in simulated reverse connection or other fault scenarios to evaluate their reliability.

[0048] In some embodiments, after applying a voltage simulation signal to the input terminal of the charger, the test system uses a variety of sensors to monitor the changes in the internal electrical parameters of the charger and the working status of the protection mechanism in real time. For example, the current sensor detects that the input current increases instantly and exceeds the preset overcurrent threshold. The system also monitors whether the overcurrent protection circuit is triggered within the specified time. If it is triggered, the normal response of the protection mechanism is recorded, otherwise it is marked as abnormal, providing a basis for subsequent improvements. For another example, the logic state sensor monitors whether the relay in the reverse protection circuit is energized to determine whether the reverse protection is effective.

[0049] S108. When the internal protection mechanism is triggered, stop sending the voltage simulation signal.

[0050] In some embodiments, once the test system determines that the internal protection mechanism of the charger is triggered through the monitoring of step S107, for example, the relay in the reverse connection protection circuit is detected to be energized, the system immediately sends a stop instruction to the voltage simulation signal generation module to stop sending the voltage simulation signal to the charger input terminal, and records the protection mechanism triggering time, triggering type and other information for the subsequent generation of test reports. If the protection mechanism is not triggered, the system will continue to apply the simulation signal for a period of time and then stop according to the preset program, and mark the protection mechanism abnormality for further investigation of the cause.

[0051] It can be seen that the test parameters are screened from the built-in adaptation database according to the charger model information. Voltage is applied to the charger input terminal based on the selected adaptation initial DC voltage value and the boost strategy. At the same time, the internal insulation resistance value is monitored in real time, and the two work together to achieve instant control of the insulation performance of the charger in the initial state of power-on. Remove the abnormal fluctuation points of the resistance value and fit the resistance change curve, and then carefully compare the resistance change curve with the qualified interval in the test parameters. Once an abnormality is found, quickly call out the timestamp and voltage, current, and resistance values ​​corresponding to the abnormal point to provide clues for troubleshooting. Send a voltage simulation signal generated by the reverse connection simulation of the input terminal and the ground wire to the charger to simulate the complex electrical environment at the moment of reverse connection, trigger the internal protection mechanism of the charger, monitor whether it responds normally, and stop sending signals in time if triggered to avoid overload damage. In this way, the insulation test and reverse connection test processes are integrated to efficiently realize the comprehensive test of the insulation and reverse connection performance of the charger, avoid the disadvantages of the separation of related technical functions and complicated operations, and solve the problems of difficult operation and high cost.

[0052] In the insulation and reverse connection test of the charger, due to the complexity and variety of actual usage scenarios, if the entire process relies on real data input, on the one hand, the data storage and processing burden of the test system may be too heavy due to excessive data volume and high collection frequency, causing the system to freeze or even crash, affecting the test efficiency; on the other hand, some extreme or rare real reverse connection situations are difficult to reproduce frequently, which is not conducive to comprehensive testing of the charger's ability to cope with various working conditions, so it is necessary to introduce simulated data.

[0053] However, current simulation data has significant defects. It is far from enough to simply simulate the voltage simulation signal generated by the reverse connection between the charger input terminal and the ground wire. Because when the actual reverse connection occurs, the line inductance and capacitance will be charged and discharged instantly, which will not only cause a sharp change in voltage and current, and produce millisecond or even microsecond spike pulses, but also breed abundant harmonic interference due to the nonlinear characteristics of the charging and discharging process, making the electrical environment highly complex.

[0054] At the same time, at this stage, for chargers, the available data, whether it is the data accumulated in the early R&D process or the fault records in actual operation and maintenance, is extremely scarce, making it difficult to support the demand for accurate simulation of complex electrical characteristics. This results in the inability to accurately restore the real scene when simulating reverse connection tests.

[0055] See also Figure 2 , Figure 2 is another flow chart of the charger insulation and reverse connection test method in the embodiment of the present application; Therefore, before step S106, the method further includes: S201, collecting harmonic data groups generated by chargers of different models under the same test procedure framework; Among them, the same test procedure framework refers to a set of standardized operating guidelines that are uniformly formulated and cover basic test processes, parameter setting ranges, data collection standards, etc., to ensure that different models of chargers are tested under comparable conditions, such as stipulating a unified initial voltage loading method, resistance measurement time interval, etc. The harmonic data group refers to a series of sinusoidal wave components of different frequencies, amplitudes, and phases generated by the distortion of current and voltage waveforms due to the action of nonlinear elements (such as diodes, transistors, etc.) in the circuit during the operation or testing of the charger. These harmonic data reflect the details of the electrical characteristics of the charger under specific working conditions.

[0056] In some embodiments, due to the extremely scarce historical data accumulated in the current charger R&D and operation and maintenance, it is difficult to support the demand for accurate simulation of complex electrical characteristics, especially when simulating reverse connection tests, it is impossible to accurately restore the real scene, which reduces the credibility of the test results. To solve this dilemma, expand the scope of data collection. Effectively make up for the shortcomings of insufficient historical data and improve the accuracy and reliability of simulated reverse connection tests.

[0057] S202, determining the harmonic frequency value range, the upper and lower limits of the amplitude at different frequencies, and the phase allowable deviation range according to the harmonic data group; Among them, the harmonic frequency value range refers to the interval span of all harmonic frequencies covered in the collected harmonic data group, which reflects the diversity of harmonic frequencies that the charger may generate. The upper and lower limits of the amplitude at different frequencies are used to define the maximum and minimum values ​​of the voltage or current amplitude corresponding to each specific harmonic frequency. The phase allowable deviation range takes into account that in the actual circuit, due to the presence of components such as inductance and capacitance, the phase of the harmonic signal will produce a certain deviation relative to the reference signal. This range specifies the acceptable range of this deviation.

[0058] In some embodiments, after completing the acquisition of the harmonic data group, the harmonic data is first subjected to a fast Fourier transform (FFT) to convert the time domain signal into a frequency domain signal, clearly presenting each harmonic component. Then, through the big data statistical analysis method, all harmonic data are traversed to find the minimum and maximum values ​​of the frequency and determine the range of harmonic frequency values; for each frequency component, the maximum and minimum values ​​of its amplitude are counted to determine the upper and lower limits of the amplitude at different frequencies; at the same time, the offset of each harmonic phase relative to the reference phase is calculated, and the phase allowable deviation range is determined in combination with the phase fluctuation tolerance of the normal operation of the charger, and finally a complete and accurate set of parameter ranges is obtained to guide subsequent simulation operations.

[0059] In some specific embodiments, data are statistically divided into frequency bands according to a predetermined frequency resolution; in each frequency band, the maximum and minimum amplitude values ​​are found through a sorting algorithm, which serve as the upper and lower limits of the amplitude of the frequency band; the phase difference between each harmonic and the fundamental wave is calculated, and the phase differences are grouped together using a clustering analysis method, and the center value and the allowable deviation range of each group are determined, thereby obtaining the allowable phase deviation range, which is not limited here.

[0060] S203, recording the circuit architecture into the analog circuit; It should be noted that the circuit architecture here refers to the model information of the charger in step S101.

[0061] Among them, the circuit architecture refers to the topological structure of the electronic circuit inside the charger, including the connection methods of key components such as the rectifier bridge, filter capacitor, transformer, and power switch tube. It determines the charger's power conversion efficiency, voltage and current characteristics, and response to external interference. The circuit architectures of different models of chargers vary significantly. An analog circuit is an experimental platform built using electronic components (such as resistors, capacitors, inductors, transistors, etc.) that can simulate the electrical characteristics of actual circuits to a certain extent. It can adjust circuit parameters, simulate faults, and provide convenience for studying the working principles and test methods of chargers. Entering the circuit architecture into the analog circuit means accurately restoring each component and its connection relationship in the analog circuit according to the actual circuit connection method of the charger, and constructing an equivalent simulation model.

[0062] S204, changing the circuit structure in the analog circuit so that the input terminal is reversely connected to the ground line; In some embodiments, after completing the construction of the analog circuit and confirming that it is working properly, the technician finds the node representing the input end of the charger in the analog circuit according to the reverse connection test requirements, and uses a wire to physically connect the node to the node representing the ground line to achieve a change in the circuit architecture.

[0063] S205, start the analog circuit simulation program, record the voltage waveform when the current changes from a steady state to a jump state, and obtain the fundamental wave; In some embodiments, after completing the reverse connection change of the analog circuit, start the analog circuit simulation program installed on the computer, such as SPICE software. First, set the initial parameters of the analog circuit in the software, including power supply voltage, frequency, component parameters, etc., so that it fully matches the actual analog circuit. Then, run the simulation, the software will numerically solve the circuit according to the set time step, and accurately calculate the current and voltage values ​​at each time node. During the simulation process, pay special attention to the time period when the current suddenly jumps from the steady state, and use the data acquisition function of the software to record the voltage waveform of the key nodes in this time period. These waveform data are stored in the computer memory. Finally, through the signal processing algorithm, the fundamental component is extracted from the recorded voltage waveform, and its parameters such as amplitude, frequency and phase are determined to provide basic data for subsequent steps.

[0064] S206, selecting harmonic frequency, amplitude and phase parameters from the harmonic frequency value range, the upper and lower limits of the amplitude at different frequencies and the allowable phase deviation range, and superimposing them on the fundamental wave obtained by the circuit simulation process to obtain a superimposed waveform; Among them, the harmonic frequency value range, the upper and lower limits of the amplitude at different frequencies, and the allowable phase deviation range are the key parameters determined in step S202. They limit the frequency, amplitude and phase characteristics of the harmonics required to be superimposed when simulating reverse connection, ensuring that the simulated electrical environment is consistent with the actual reverse connection fault scenario.

[0065] In some embodiments, harmonic data that meets the harmonic frequency value range is screened out from the stored harmonic data group, and harmonic components with appropriate amplitude and phase are further selected according to the upper and lower limits of amplitude and the allowable deviation range of phase at different frequencies to ensure that the parameters of each harmonic are within the specified range. Then, using the signal synthesis function of the software, these selected harmonics are linearly superimposed with the fundamental wave, and according to the mathematical formula: the time domain expression of the superimposed waveform is calculated, and the amplitude and phase values ​​of the superimposed waveform at different time points are obtained by numerical calculation, and finally a complete superimposed waveform data is generated to prepare for the subsequent conversion into an actual applicable voltage analog signal.

[0066] S207 , performing digital-to-analog conversion on the superimposed waveform to obtain a voltage analog signal.

[0067] In some embodiments, after the superimposed waveform data is generated, the data is transmitted to a high-precision digital-to-analog converter (DAC) and the conversion is started. The DAC converts the input superimposed waveform digital data point by point into an analog voltage value according to the set parameters and outputs a continuous voltage analog signal through its output port.

[0068] It can be seen that the harmonic data groups of different types of chargers under the same test procedure framework are first collected. These data, which are derived from reality and have been sorted, provide a basis for subsequent simulation. Determine the value range of key parameters based on the harmonic data group, and then select appropriate parameters to superimpose on the fundamental wave obtained by the circuit simulation process, and finally convert them into voltage simulation signals. On the one hand, this data-driven simulation signal generation method avoids the problem of data storage and processing overload caused by the pursuit of full coverage of real data, ensuring the smooth operation of the test system; on the other hand, it accurately simulates the complex reverse electrical environment containing rich harmonic interference and spike pulses, solving the dilemma of extreme reverse connection conditions that are difficult to reproduce and inaccurate simulation, and effectively improves the credibility of the test results.

[0069] It can be seen that the actual circuit architecture is recorded into the simulation circuit and its input end is reversed to the ground wire, and then the simulation program is started to record the voltage waveform under specific current changes to obtain the fundamental wave. This process accurately restores the changes in electrical characteristics caused by the charging and discharging of the line inductance and capacitance at the moment of reverse connection, providing the most realistic fundamental wave blueprint for subsequent complex simulations such as superimposed harmonics.

[0070] In large charging stations, there are often multiple charging piles running at the same time. When performing insulation and reverse connection tests on one of the charging piles, the electromagnetic radiation generated by the surrounding charging piles may interfere with the normal operation of the test equipment. For example, the high-frequency harmonics generated by the adjacent charging piles when charging at high power may penetrate into the charging pile line being tested through spatial coupling or grounding loops, and be superimposed on the test voltage signal, causing measurement errors, affecting the fitting accuracy of the insulation resistance change curve and the authenticity of the reverse connection simulation signal.

[0071] See also Figure 3 , Figure 3 is another flow chart of the charger insulation and reverse connection test method in the embodiment of the present application; Therefore, after step S102, the following steps are also included: S301, scanning the charger within a preset frequency range to obtain spectrum information of electromagnetic interference around the charger; The preset frequency range refers to a frequency span set in advance based on the common working frequency band of the charger and the frequency range that may be subject to electromagnetic interference. The spectrum information of electromagnetic interference refers to the detailed distribution of electromagnetic interference signals according to frequency components within the preset frequency range, including the amplitude and phase of the interference signals at different frequencies, which can reflect the complex situation of electromagnetic interference around the charger.

[0072] In some embodiments, this step is initiated when the accuracy of the insulation and reverse connection tests of the charger in a complex electromagnetic environment needs to be ensured. According to the preset frequency range, the space around the charger is scanned at a very high sampling rate to capture electromagnetic interference signals in real time, and the interference signals in the time domain are converted into frequency domain signals through the built-in fast Fourier transform algorithm, clearly presenting the spectrum information of electromagnetic interference, providing basic data for subsequent analysis and response to interference.

[0073] In some specific embodiments, a distributed spectrum monitoring system is used to arrange multiple small spectrum monitoring nodes at different locations around the charger, and these nodes are connected to the central server through wireless communication modules; the monitoring frequency range of each node is remotely set on the central server to enable it to perform a full-scale scan of the charger synchronously; each node transmits the collected electromagnetic interference data back to the central server in real time, and the server summarizes and integrates the data to generate complete electromagnetic interference spectrum information for subsequent analysis and processing, which is not limited here.

[0074] S302, marking the interference intensity level of each frequency band according to the spectrum information; Among them, the interference intensity level of each frequency band refers to the classification and identification of the interference strength of each frequency band after the entire preset frequency range is divided into several frequency bands according to the amplitude, energy and other parameters of the interference signals in different frequency bands in the spectrum information. It can usually be divided into three levels: strong, medium and weak, or more detailed levels. For example, the frequency band with an amplitude exceeding a certain threshold (such as 1V) is marked as a strong interference level, 0.1V-1V is a medium interference level, and below 0.1V is a weak interference level. This can intuitively present the distribution of electromagnetic interference in different frequency bands.

[0075] In some embodiments, after obtaining the spectrum information of electromagnetic interference, the data is imported into professional electromagnetic analysis software. The spectrum information is divided into frequency bands, and divided into equal bandwidths or unequal bandwidths according to the characteristics of the charger's sensitive frequency bands, such as dividing the frequency bands at intervals of 10kHz. Then, for each frequency band, the total energy or amplitude average of the interference signal is counted, and the interference intensity level of each frequency band is automatically marked according to the preset intensity grading standard, and a spectrum diagram with a level mark is generated.

[0076] S303, taking the resistance value obtained during the frequency band with the lowest interference intensity level as the benchmark data; The frequency band with the lowest interference intensity level refers to the frequency range covered by the frequency band with the weakest interference among the interference intensity levels of the frequency bands marked in step S302. The electromagnetic interference in this frequency band has the least impact on the internal resistance measurement of the charger, and can be used as a relatively pure reference benchmark.

[0077] S304, using the reference data to calibrate the resistance values ​​obtained during other frequency bands, where the other frequency bands are the frequency bands except the frequency bands with the lowest interference intensity level.

[0078] In some embodiments, after determining the reference data and other frequency bands, the calibration operation begins. According to the preset calibration algorithm, combined with the interference characteristics of other frequency bands (such as interference intensity, frequency distribution, etc.), the resistance compensation coefficient corresponding to each other frequency band is calculated. Then, the resistance value obtained during the other frequency band range is multiplied by the corresponding resistance compensation coefficient to obtain the calibrated resistance value, which replaces the original measured value, thereby completing the correction of the resistance value affected by electromagnetic interference during the entire measurement process, and providing accurate data for the subsequent judgment of the insulation performance of the charger.

[0079] Step S304 specifically includes: S3041, determining the resistance compensation coefficient corresponding to other frequency bands; wherein: the resistance compensation coefficient is the product of the interference ratio and the inverse of the interference frequency band bandwidth and the exponent of the change rate plus 1; the interference ratio is the ratio of the interference peak intensity to the interference average intensity, and the exponent of the change rate is the product of the interference intensity change rate multiplied by the interference intensity coefficient and the exponent of the natural constant.

[0080] Among them, the interference ratio refers to the ratio of the peak intensity of interference to the average intensity of interference. It reflects the relationship between the peak fluctuation degree of the interference signal and the average level. The larger the ratio, the stronger the instantaneous impact of the interference signal and the more complex the impact on the resistance measurement. The reciprocal of the interference frequency band bandwidth reflects the impact of the width of the frequency band on the resistance compensation. The narrower the bandwidth, the larger its reciprocal, and the greater its weight in the compensation coefficient, because narrowband interference often has stronger pertinence and local impact. The exponent of the rate of change is the product of the interference intensity change rate multiplied by the interference intensity coefficient and the exponent of the natural constant. The interference intensity change rate reflects the speed of change of the interference intensity over time. The interference intensity coefficient is an empirical value set according to the sensitivity of the charger to interference. The exponent of the rate of change comprehensively considers the long-term impact of the dynamic change characteristics of the interference on the resistance measurement. The resistance compensation coefficient is the product of the interference ratio, the reciprocal of the interference frequency band bandwidth, and the exponent of the rate of change plus 1. This is a complex calculation formula that comprehensively considers multiple interference factors. By combining these key factors in a specific mathematical form, a coefficient that can accurately compensate for the resistance value deviation is obtained to ensure the calibration effect.

[0081] In some embodiments, when calculating the resistance compensation coefficient, first accurately extract parameters such as the interference peak intensity, the interference average intensity, the interference frequency band bandwidth, and the interference intensity change rate from the electromagnetic interference spectrum information. Then, calculate the interference ratio according to the formula, that is, the interference peak intensity divided by the interference average intensity; then calculate the inverse of the interference frequency band bandwidth; then calculate the exponent of the rate of change according to the pre-set interference intensity coefficient (such as determined by experience based on the charger model, usage scenario, etc.), that is, the product of the interference intensity change rate multiplied by the interference intensity coefficient and the exponent of the natural constant. Finally, multiply the interference ratio, the inverse of the interference frequency band bandwidth, and the exponent of the rate of change and add 1 to obtain the resistance compensation coefficient.

[0082] S3043. Multiply the resistance value obtained during other frequency bands by the corresponding resistance compensation coefficient.

[0083] The resistance compensation coefficient is the key value determined in step S304 for correcting the resistance deviation. The resistance value obtained during other frequency bands is multiplied by the corresponding resistance compensation coefficient, which is to use the obtained resistance compensation coefficient to multiply the interfered resistance value. Through this mathematical correction method, the resistance value is adjusted to a value close to the real value in the absence of interference, thereby improving the accuracy of resistance measurement and providing a reliable basis for subsequent judgment of the insulation performance of the charger.

[0084] It can be seen that the electromagnetic interference spectrum information is obtained by scanning the charger in the preset frequency range, accurately marking the interference intensity level of each frequency band, finding the frequency band with the lowest interference intensity, and using the resistance value in this period as the benchmark data to calibrate the resistance values ​​of other frequency bands. In the environment of large-scale charging stations where multiple charging piles are running at the same time, the electromagnetic radiation interference of adjacent charging piles is effectively resisted. With reliable benchmark data as a reference, the resistance measurement value distorted by the superposition of interference such as high-frequency harmonics is calibrated to ensure that the fitting accuracy of the insulation resistance change curve is not affected, maintain the authenticity of the reverse connection simulation signal, so that the test data can truthfully reflect the status of the charger, improve the test accuracy, and provide a basis for subsequent judgment of the insulation and reverse connection performance of the charger.

[0085] It can be seen that the resistance compensation coefficient corresponding to other frequency bands is determined, and then the resistance value obtained in this frequency band is multiplied by the compensation coefficient. This can put the resistance measurement data back on track, avoid the accumulation of measurement errors caused by interference, and ensure the accuracy of insulation resistance measurement.

[0086] It can be seen that the resistance compensation coefficient is composed of the product of the interference ratio, the inverse of the interference frequency band bandwidth, and the rate of change index plus 1, where the interference ratio reflects the fluctuation characteristics of the interference intensity, the inverse of the interference frequency band bandwidth reflects the concentration of the interference energy, and the rate of change index covers the dynamic change weight of the interference. Such a finely constructed compensation coefficient comprehensively considers the multi-dimensional characteristics of electromagnetic interference and quantifies the impact of complex and changeable electromagnetic interference on the resistance value into a precise coefficient. When facing electromagnetic interference of different intensities, frequency bands, and dynamic changes, the resistance measurement value can be accurately corrected by this coefficient, and the real resistance without interference can be restored to the greatest extent, making the test data stable and reliable.

[0087] The following introduces an exemplary charger insulation and reverse connection testing system 400 provided in an embodiment of the present application. Figure 4 Schematic diagram of an exemplary hardware structure of a charger insulation and reverse connection test system 400 provided in an embodiment of the present application.

[0088] In some embodiments, the charger insulation and reverse connection test system 400 is a computer device or the charger insulation and reverse connection test system 400 includes a computer device. The computer device includes a processor, a memory and a network interface connected via a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data. The network interface of the computer device is used to communicate with other external terminals or servers through a network connection. In some embodiments, the network interface can be a wired network interface, and in some embodiments, the network interface can also be a wireless network interface. When the computer program is executed by the processor, the method in the embodiment of the present application is implemented.

[0089] Those skilled in the art will understand that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0090] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0091] As used in the above embodiments, the term "when..." may be interpreted to mean "if..." or "after..." or "in response to determining..." or "in response to detecting...", depending on the context. Similarly, the phrases "upon determining..." or "if (the stated condition or event) is detected" may be interpreted to mean "if determining..." or "in response to determining..." or "upon detecting (the stated condition or event)" or "in response to detecting (the stated condition or event)", depending on the context.

[0092] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk), etc.

[0093] Those skilled in the art can understand that to implement all or part of the processes in the above-mentioned embodiments, the processes can be completed by computer programs to instruct related hardware, and the programs can be stored in computer-readable storage media. When the programs are executed, they can include the processes of the above-mentioned method embodiments. The aforementioned storage media include: ROM or random access memory RAM, magnetic disk or optical disk and other media that can store program codes.

Claims

1. A charger insulation and reverse connection test method, characterized in that: include: Filter out test parameters from the built-in adaptation database according to the input charger model information; Applying a DC voltage to the input terminal of the charger according to the adapted initial DC voltage value and the boost strategy in the test parameters, while monitoring the insulation resistance value inside the charger; Remove abnormal fluctuation points of resistance value and fit the resistance change curve; Comparing the resistance change curve with the qualified interval in the test parameters; In the case where there is an abnormal point that causes the comparison to be unqualified, the timestamp corresponding to the abnormal point and the corresponding voltage, current, and resistance values ​​are called out; Sending a voltage simulation signal to the charger, wherein the voltage simulation signal is obtained when the charger input terminal is reversely connected to the ground wire; Monitor whether the internal protection mechanism of the charger is triggered; When the internal protection mechanism is triggered, the voltage analog signal is stopped.

2. The method according to claim 1, characterized in that: Before the step of sending a voltage simulation signal to the charger, the method further includes: Collect the harmonic data sets generated by chargers of different models under the same test procedure framework; Determine the harmonic frequency value range, the upper and lower limits of the amplitude at different frequencies, and the allowable phase deviation range according to the harmonic data group; Harmonic frequency, amplitude and phase parameters are selected from the harmonic frequency value range, the upper and lower limits of the amplitude at different frequencies, and the allowable phase deviation range, and superimposed on the fundamental wave obtained by the circuit simulation process to obtain a superimposed waveform; The superimposed waveform is converted from digital to analog to obtain the voltage analog signal.

3. The method according to claim 2, characterized in that Before the step of superimposing the waveform onto the fundamental wave obtained by the circuit simulation process to obtain the superimposed waveform, the method further includes: Record the circuit architecture into the analog circuit; Change the circuit structure in the analog circuit so that the input terminal is connected to the ground line in reverse; The analog circuit simulation program is started, and the voltage waveform when the current changes from a steady state to a jump state is recorded to obtain the fundamental wave.

4. The method according to claim 1, characterized in that After the step of applying a DC voltage to the input terminal of the charger according to the adapted initial DC voltage value and the boost strategy in the test parameters and monitoring the internal insulation resistance value of the charger, the method further includes: Scan the charger within a preset frequency range to obtain spectrum information of electromagnetic interference around the charger; Mark the interference intensity level of each frequency band based on the spectrum information; The resistance value obtained during the frequency band range with the lowest interference intensity level is used as the baseline data; The reference data is used to calibrate the resistance value obtained during the calibration of other frequency bands, where the other frequency bands are the frequency bands other than the frequency band with the lowest interference intensity level.

5. The method according to claim 4, characterized in that The step of using the reference data to calibrate the resistance value obtained during the frequency band range except the frequency band with the lowest interference intensity level specifically includes: Determine the resistance compensation coefficient corresponding to other frequency bands; The resistance values ​​obtained during other frequency ranges are multiplied by the corresponding resistance compensation coefficient.

6. The method according to claim 5, characterized in that The step of determining the resistance compensation coefficient corresponding to other frequency bands specifically includes: The resistance compensation coefficient is the product of the interference ratio, the inverse of the interference frequency band bandwidth, and the exponent of the change rate plus 1; the interference ratio is the ratio of the interference peak intensity to the interference average intensity, and the exponent of the change rate is the product of the interference intensity change rate multiplied by the interference intensity coefficient and the exponent of the natural constant.

7. The method according to claim 1, characterized in that The step of removing abnormal fluctuation points of the resistance value specifically includes: The resistance value whose change rate between adjacent resistance values ​​is higher than a threshold value is determined as the abnormal fluctuation point, and the abnormal fluctuation point is removed.

8. A charger insulation and reverse connection test system, characterized in that: The charger insulation and reverse connection test system comprises: one or more processors and a memory; the memory is coupled to the one or more processors, the memory is used to store computer program code, the computer program code comprises computer instructions, and the one or more processors call the computer instructions to enable the charger insulation and reverse connection test system to execute the method as described in any one of claims 1-7.

9. A computer program product comprising instructions, characterized in that When the computer program product runs on a charger insulation and reverse connection test system, the charger insulation and reverse connection test system is enabled to perform the method according to any one of claims 1 to 7.

10. A computer-readable storage medium comprising instructions, characterized in that: When the instruction is executed on a charger insulation and reverse connection test system, the charger insulation and reverse connection test system is enabled to perform the method according to any one of claims 1 to 7.

Images