A comprehensive testing device and testing method applied to a power filter

Abstract

This invention relates to the field of electrical safety testing technology, and discloses a comprehensive testing device and method for power supply filters. The method includes: performing closed-loop correction of the contact impedance of the test circuit before applying the test voltage; intelligently selecting parallel or sequential excitation mode to apply high voltage based on pre-test results; acquiring leakage current waveforms in real time during the test, comparing them with preset insulation failure precursor characteristics, and rapidly cutting off the high voltage within microseconds through an independent hardware channel during matching; calculating the dispersion of batch leakage current after the test and comparing it with a threshold adaptively updated based on historical data. The corresponding device includes a high-voltage matrix switch network, an adaptive tooling matrix, a safety monitoring module, and a host computer. This invention achieves reliable test connection assurance, proactive safety protection during the test process, and intelligent optimization capabilities for the test strategy.

Description

Technical Field

[0001] This invention relates to the field of electrical safety testing technology, specifically to a comprehensive testing device and method for power supply filters. Background Technology

[0002] Power filters are critical components in electronic devices used to suppress electromagnetic interference. Since they are directly connected to the power grid, their insulation performance directly affects the safety of the entire device. During final product inspection, strict testing according to safety standards is required to avoid potential safety hazards. Therefore, it is necessary to measure the leakage current of the filter at its rated operating voltage (mainly the leakage current generated by the Y capacitor) to ensure that the leakage current does not exceed the safety threshold (e.g., 0.75). Or 3.5 (Set according to the application scenario) to avoid the risk of electric shock.

[0003] Currently, leakage current testers are commonly used to test their performance. By connecting the filter to the rated operating voltage and connecting the tester in series in the circuit, the leakage current value is measured sequentially and compared with the safety standard. If it exceeds the threshold, it is judged as unqualified. However, in this process, there is often a parallel testing mode adopted to improve testing efficiency, which makes it difficult to take into account the in-depth characteristic scanning of each individual product, and the testing strategy lacks flexibility. Secondly, the judgment of batch product consistency mostly relies on fixed thresholds, which cannot be adaptively adjusted with the natural fluctuations of the production process.

[0004] Therefore, a testing solution that can comprehensively address both contact reliability and testing safety is needed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a comprehensive testing device and method for power filters; it is suitable for efficient, reliable, and safe automated testing of leakage current and insulation performance of power filters during mass production.

[0006] The technical solution adopted by this invention to solve its technical problem is a comprehensive testing method applied to power supply filters.

[0007] The method includes

[0008] Step A: Apply test voltages to multiple power filters under test;

[0009] Step B: During the application of the test voltage, monitor the leakage current signal of each power supply filter under test in real time;

[0010] Step C: Compare the waveform characteristics of the leakage current signal with the pre-stored insulation failure judgment characteristics in real time;

[0011] Step D: When the comparison result meets the pre-fault conditions, cut off the test voltage of the corresponding power supply filter under test.

[0012] On the other hand, before applying the test voltage in step A, a contact state correction step E is also included.

[0013] This involves monitoring the contact impedance between the test circuit and the power supply filter under test, and adjusting the circuit connection status until it meets the requirements when an abnormal contact impedance is detected.

[0014] Preferably, the specific step E of adjusting the circuit connection state is as follows:

[0015] By driving a micro servo mechanism to fine-tune the probe pressure and simultaneously collecting the voltage drop and loop current at both ends of the contact point, the change in the contact impedance is calculated and monitored in real time. When the contact impedance reaches the preset range, the micro servo mechanism is locked. If the value deviates from the preset tolerance range, the probe pressure is gradually increased until the impedance stabilizes within the qualified range. The entire process supports multi-channel parallel calibration.

[0016] Preferably, in step A, applying test voltages to multiple power filters under test employs either a parallel excitation mode or a sequential excitation mode. The parallel excitation mode involves synchronously applying the same test voltage to all power filters under test; the sequential excitation mode involves applying test voltages sequentially and at different times to different power filters or groups under test via a switching network.

[0017] Further preferably, the selection of the excitation mode is based on pre-test results or product specification information. The pre-test includes performing a voltage sequence scan on the first or first few products in the batch to obtain the response curve of its leakage current as a function of voltage, and calculating the matching degree of the curve with the historical qualified data model library. If the matching degree is higher than a preset threshold, an efficient parallel excitation mode is used for testing the entire batch; if the matching degree is lower than the preset threshold or it is a new specification product, a more reliable sequential excitation mode is used for testing.

[0018] Preferably, the insulation failure determination feature includes at least one of the current pulse rise edge steepness, pulse width, and pulse repetition frequency.

[0019] Preferably, the insulation failure determination feature is: rising edge steepness greater than 10. The pulse width is 50 Up to 200 Between, and / or pulse repetition frequency in 1 Up to 10 between.

[0020] Preferably, the total delay from meeting the pre-fault conditions to cutting off the test voltage does not exceed 100 microseconds. Real-time comparison and the generation of the cut-off command are completed through a hardware direct connection channel or an independent communication link with the highest priority to bypass the delay of conventional software communication.

[0021] Preferably, after completing a batch test, a batch evaluation step is also included:

[0022] S1: Calculate the dispersion of the stable leakage current value of this batch of products;

[0023] S2: Compare the dispersion with the judgment threshold and output the consistency evaluation conclusion of the batch of products;

[0024] S3: The judgment threshold is based on the test data of historical qualified batches and is adaptively adjusted through statistical analysis;

[0025] S4: If the consistency evaluation conclusion is abnormal, the relevant products will be automatically subjected to a retest by increasing the test voltage or extending the test time.

[0026] Secondly, the present invention provides a testing device for implementing the above method, comprising a high-voltage matrix switch network, an adaptive tooling matrix, a safety monitoring module, and a host computer.

[0027] The high-voltage matrix switch network is connected to each test channel and is used to apply the corresponding test voltage to each test channel according to the excitation mode, and to receive instructions from the safety monitoring module to cut off the test voltage of abnormal channels.

[0028] The adaptive tooling matrix is ​​set up for each independent test station. Its detection unit is used to monitor the contact impedance of the test circuit, and the correction mechanism is used to perform closed-loop fine adjustment for stations with abnormal contact impedance.

[0029] The safety monitoring module is used to collect transient leakage current waveforms of each test circuit in real time, compare them with the feature library of waveforms indicating insulation failure, and generate high-voltage disconnection commands.

[0030] The host computer is connected to the high-voltage matrix switch network, the adaptive tooling matrix, and the safety monitoring module, respectively, and is used to select the excitation mode, receive feedback signals from each module, and perform batch leakage current data calculation, analysis and evaluation.

[0031] The beneficial effects of this invention are as follows:

[0032] This invention can adaptively select the optimal testing strategy according to product characteristics, improve batch testing efficiency while ensuring test coverage depth, and make the judgment criteria more in line with the actual production process level by dynamically updating the batch consistency evaluation system based on historical data. Attached Figure Description

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Figure 1 This is a schematic diagram of the power supply filter under test in this invention;

[0035] Figure 2 This is the main flowchart for testing the filter;

[0036] Figure 3 This is the main test logic flowchart of the method from start to finish;

[0037] Figure 4 This is a flowchart of the adaptive tooling matrix closed-loop correction process in this method;

[0038] Figure 5 This is a flowchart illustrating the collaborative process between the safety monitoring module and data fusion analysis in this method.

[0039] Figure 6 This is a structural diagram of the power filter testing device. Detailed Implementation

[0040] To make the technical means, creative features, objectives, and effects of this invention easier to understand, the following is a summary.

[0041] The present invention will be further described in conjunction with specific embodiments.

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0043] Example 1: A comprehensive test method applied to power supply filters

[0044] like Figure 1 , Figure 2 and Figure 4 As shown, the method provided in this embodiment mainly includes the following core steps: contact state correction (step E), application of test voltage (step A), real-time monitoring and pre-fault protection (steps B, C, D), and batch data evaluation.

[0045] The execution of this method begins with contact state calibration before testing: each station injects a constant micro-current (e.g., 10) into the test circuit through the detection unit. The voltage drop between the filter terminals and the probe is collected, and the contact impedance is calculated in real time according to Ohm's law. The calculation formula is as follows:

[0046] in, Indicates contact resistance. Indicates voltage drop. This indicates the test current.

[0047] If the impedance exceeds the preset range (e.g., 1 to 10), Then the micro servo mechanism is driven in microsteps (e.g., 5). (Step 1) Adjust the pressure of the probe while continuously monitoring the impedance change until it falls into the qualified range and then lock the mechanism. All channels execute this process in parallel to ensure reliable electrical connection.

[0048] Once the contact state is ready, the system enters the excitation mode decision and high-pressure application stage (step A). ​​For example... Figure 3 and Figure 5 As shown, the decision logic is based on pre-test results. For a new batch, the system selects the first sample and applies a voltage from the initial voltage (e.g., 500V) to the rated test voltage. A stepped voltage scan (e.g., 1500V) is used to record the stable leakage current at each voltage point, forming a leakage current-voltage response curve. The matching score between this curve and a benchmark curve in the historical qualified product database is calculated. The matching score can be evaluated using the following formula.

[0049] in, This represents the match score; Indicates the summation index, from 1 to... , representing the One voltage point; Indicates the first Each scan voltage value For the sample at voltage The leakage current value below; For the historical baseline curve The corresponding leakage current reference value; The number of voltage points to scan is a positive integer representing the number of voltage steps set in the pre-tested voltage sequence scan; This is a normalization factor (usually taken as the difference between the maximum and minimum values ​​of leakage current in the historical reference curve), used to normalize the root mean square error (RMSE) to the range of 0 to 1, so that... (Comparable); the numerator in the formula This is the root mean square error (RMSE) between the current curve and the reference curve.

[0050] If the score is higher than a preset threshold (e.g., 0.90), the characteristics of this batch of products are determined to be consistent with those of historical qualified products. In this case, a parallel excitation mode is selected, and high voltage matrix switching network is used to synchronously apply excitation to all channels. Voltage is selected to achieve maximum testing efficiency. If the score is below the threshold or the product is a new specification, the sequential excitation mode is selected, and the channels are grouped by a programmable switch, and voltage is applied to each group sequentially. Voltage, so that each channel can be monitored more independently, which is suitable for situations where the characteristics are unknown.

[0051] like Figure 3 and Figure 5 As shown, after high voltage is applied, the system performs real-time safety monitoring and pre-fault protection in parallel (steps B, C, and D). The safety monitoring module uses a high sampling rate (e.g., 100). The system continuously acquires leakage current waveforms from each channel. In the hardware logic (such as an FPGA), transient characteristic parameters of the waveforms are extracted in real time, including the rise time steepness of the current pulse. Pulse width and pulse repetition frequency These parameters are then compared at high speed with a pre-stored database of precursor features of insulation failure. Precursor features are defined as follows: >10 , ,and When the features extracted in real time simultaneously meet multiple of the above conditions, the FPGA will determine the risk of insulation failure within microseconds and send an emergency disconnect command directly to the high-voltage matrix switch network through a hardware direct connection channel (such as an optocoupler-isolated GP1IO) independent of the main communication. This design ensures that the total delay from feature recognition to relay action to disconnect the corresponding channel's high voltage is controlled within 100 microseconds, thereby preventing potential faults from evolving into substantial damage.

[0052] After a batch (assuming it contains N samples) is tested, the system performs batch data fusion analysis and evaluation. For example... Figure 3 and Figure 5 As shown, firstly, the measured final leakage current value of each sample under a stable test voltage is recorded. Next, the arithmetic mean of the leakage current for this batch is calculated. with sample standard deviation , The value serves as a key dispersion metric for measuring batch consistency. The specific calculation formula is as follows:

[0053] Arithmetic mean formula

[0054] Batch dispersion formula

[0055] in This represents the arithmetic mean of the leakage current of all samples in this batch; This indicates the total number of samples tested in this batch; Indicates the summation index, from 1 to... , representing the One sample; Indicates the first The final leakage current value measured for each sample under a stable test voltage; This represents the sample standard deviation of the leakage current data for that batch, i.e., the batch dispersion. This represents the sum of squared deviations, which is the sum of the squares of the differences between the leakage current of each sample and the average value.

[0056] The system maintains a historical database of qualified batches, which stores all batches that have been judged to be qualified in the past. Value. The threshold value used for comparison. It is not fixed, but rather updated periodically using statistical methods based on historical data. The calculation formula is as follows:

[0057] in, This represents the newly calculated adaptive decision threshold; Indicates the dispersion of historical qualified batches ( The arithmetic mean of the values; Indicates the dispersion of historical qualified batches ( The standard deviation of the value; This represents the expansion factor, which is a positive number (usually 2 or 3).

[0058] For example, history can be calculated. mean of values and standard deviation And set the new judgment threshold as +2 or +3 The current batch Value and latest Comparison: If ≤ If so, the output will be "Batch consistency is acceptable"; if... > If the result is not found, the system will output a "batch consistency anomaly" conclusion. For anomaly conclusions, the system will automatically trigger additional verification tests, such as applying a 1.2 times higher voltage to samples with excessive leakage current. The voltage should be retested or the stabilization time should be doubled to confirm the result.

[0059] like Figure 6 As shown, this embodiment provides a testing device for implementing the above method. The device mainly includes a high-voltage matrix switch network, an adaptive tooling matrix, a safety monitoring module, and a host computer.

[0060] The high-voltage matrix switch network consists of a programmable high-voltage power supply, a multi-channel high-voltage relay array, and corresponding drive and protection circuits. It receives excitation mode commands from the host computer and executes parallel or sequential high-voltage application; simultaneously, it receives emergency disconnection commands from the safety monitoring module through a dedicated hardware link, enabling rapid (microsecond-level) disconnection of the high voltage of the corresponding test channel.

[0061] The adaptive tooling matrix comprises multiple physically independent test stations, each integrating a detection unit and a calibration mechanism. The detection unit typically includes a precision constant current source and a high input impedance voltage measurement circuit for measuring contact impedance. The calibration mechanism includes a miniature servo motor, pressure sensor, and precision transmission components to provide accurate force feedback and position control during micro-displacement feeds.

[0062] The core of the safety monitoring module is a high-speed analog-to-digital converter (ADC) and a field-programmable gate array (FPGA). The ADC is responsible for synchronously acquiring the transient leakage current analog signals of each channel and converting them into digital waveforms. The FPGA has embedded waveform feature extraction algorithms, real-time comparison logic, and protection command generation logic, enabling microsecond-level pre-fault judgment and command output independently of the host computer software.

[0063] The host computer is an industrial control computer running dedicated test management software. It is responsible for coordinating and controlling the overall test process, including initiating contact correction, executing excitation mode decisions, receiving and processing status and data feedback from each module, as well as performing statistical analysis of batch data, threshold adaptive algorithms, and generating the final evaluation report. Modules interact with each other via a communication bus (such as Ethernet), while the safety monitoring module and the high-voltage matrix switch network have an independent hardware direct connection channel as described above to ensure the ultimate response speed of safety protection.

[0064] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for comprehensive testing applied to a power filter, characterized in that, The method includes: A: Apply test voltages to multiple power filters under test; B: During the application of the test voltage, the leakage current signal of each power supply filter under test is monitored in real time. C: The waveform characteristics of the leakage current signal are compared with the pre-stored insulation failure judgment characteristics in real time; D: When the comparison result meets the pre-fault condition, cut off the test voltage of the corresponding power supply filter under test; In step A, test voltages are applied to multiple power filters under test in either a parallel excitation mode or a sequential excitation mode. The parallel excitation mode involves applying the same test voltage to all power filters under test simultaneously. The sequential excitation mode involves applying test voltages to different power filters or groups under test sequentially and at different times through a switching network. The selection of the excitation mode is based on the pre-test results or product specification information; the pre-test includes performing a voltage sequence scan on the first or first few products in the batch to obtain the response curve of its leakage current changing with voltage, and calculating the matching degree of the curve with the historical qualified data model library. If the matching degree is higher than a preset threshold, the efficient parallel excitation mode is used for full batch testing; if the matching degree is lower than the preset threshold or it is a new specification product, the more reliable sequential excitation mode is used for testing.

2. The comprehensive testing method for power supply filters according to claim 1, characterized in that: Before applying the test voltage, a contact condition correction step E is also included. This involves monitoring the contact impedance between the test circuit and the power supply filter under test, and adjusting the circuit connection status until it meets the requirements when an abnormal contact impedance is detected.

3. The method for comprehensive testing of a power filter according to claim 2, characterized in that: The specific steps for adjusting the circuit connection state E are as follows: The probe pressure is finely adjusted by driving a micro servo mechanism, and the voltage drop and loop current at both ends of the contact point are collected simultaneously to monitor the change in contact impedance in real time. When the contact impedance reaches a preset range, the micro servo mechanism is locked. When the value deviates from the preset tolerance range, gradually increase the probe pressure until the impedance stabilizes within the qualified range. The entire test process supports multi-channel parallel calibration.

4. The method of claim 1, wherein the method is applied to a power filter. The step of applying test voltages to multiple power supply filters under test adopts either a parallel excitation mode or a sequential excitation mode. The parallel excitation mode involves synchronously applying the same test voltage to all power filters under test. The sequential excitation mode involves applying test voltages sequentially and at different times to different power supply filters or groups under test via a switching network.

5. The method for comprehensive testing of a power filter according to claim 4, characterized in that: The selection of the excitation mode is based on the pre-test results or product specification information. The pre-test includes performing a voltage sequence scan on the first or first few products in the batch, and determining the excitation mode to be used based on the matching degree between its leakage current response curve and historical data.

6. The comprehensive testing method for power supply filters according to claim 1, characterized in that: The insulation failure determination features include at least one of the following: the rise steepness of the current pulse, the pulse width, and the pulse repetition frequency.

7. The method of claim 6, wherein the method is applied to a power filter. The insulation failure determination characteristic is: rising edge steepness greater than 10. The pulse width is 50 Up to 200 Between, and / or pulse repetition frequency in 1 Up to 10 between.

8. The comprehensive testing method for power supply filters according to claim 1, characterized in that: The total delay from meeting the pre-fault conditions to cutting off the test voltage does not exceed 100 microseconds. Real-time comparison and the generation of the cut-off command are completed through a hardware direct connection channel or an independent communication link with the highest priority.

9. A comprehensive testing method for power supply filters according to claim 8, characterized in that: Calculate the dispersion of the stable leakage current values ​​for this batch of products; The dispersion is compared with the judgment threshold to output the consistency evaluation conclusion of the batch of products; The judgment threshold is based on test data of historical qualified batches and is adaptively adjusted through statistical analysis; If the consistency evaluation conclusion is abnormal, the relevant products will be automatically subjected to a retest by increasing the test voltage or extending the test time.

10. The test apparatus for use in the integrated test method of power filters according to any one of claims 1 to 9, characterized in that, The comprehensive test of the power filter is used for leakage current detection of the power filter. It measures the leakage current of the filter under the rated operating voltage to ensure that the leakage current does not exceed the safety threshold and avoid the risk of electric shock. The test equipment used includes a high-voltage matrix switch network, an adaptive tooling matrix, a safety monitoring module and a host computer. The high-voltage matrix switch network is connected to each test channel and is used to apply the corresponding test voltage to each test channel according to the excitation mode, and to receive instructions from the safety monitoring module to cut off the test voltage of abnormal channels. The adaptive tooling matrix is ​​set up for each independent test station. Its detection unit is used to monitor the contact impedance of the test circuit, and the correction mechanism is used to perform closed-loop fine adjustment for stations with abnormal contact impedance. The safety monitoring module is used to collect transient leakage current waveforms of each test circuit in real time, compare them with the feature library of waveforms indicating insulation failure, and generate high-voltage disconnection commands. The host computer is connected to the high-voltage matrix switch network, the adaptive tooling matrix, and the safety monitoring module, respectively, and is used to select the excitation mode, receive feedback signals from each module, and perform batch leakage current data calculation, analysis and evaluation.

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