A high-low voltage DC contactor fault detection device

Abstract

The application discloses a kind of high-low voltage DC contactor fault detection devices, it is related to contactor fault detection technical field, the application is aimed at single high-low voltage DC contactor, first according to electrical property is divided into coil current, main contact voltage, auxiliary contact state and loop on-off, real-time acquisition is carried out by multi-channel electrical detection equipment, then extraction fault determination link parameter constructs control parameter-fault state dynamic evaluation model and calculates fault risk comprehensive index, real-time acquisition parameter is substituted into model, and difference rate calculation and threshold comparison determine operating state and output result and core abnormal value, finally retest parameter after fault handling and optimize abnormal link detection process.The application realizes the accurate detection of contactor operating state and the effective disposal of fault by quantitative determination based on dynamic evaluation model and retest optimization after fault handling, greatly improves fault detection accuracy and contactor operating reliability.

Description

Technical Field

[0001] This invention relates to the field of contactor fault detection technology, and more specifically to a high and low voltage DC contactor fault detection device. Background Technology

[0002] High and low voltage DC contactors are widely used in new energy vehicles, energy storage systems, and power electronic equipment. As the core component for switching the main circuit, their reliability directly affects the safe and stable operation of the entire equipment or system. Under long-term, high-frequency start-stop, high-low voltage switching, and complex operating conditions, DC contactors are prone to faults such as main contact sticking, main contact not closing, coil open / short circuit, and poor contact of auxiliary contacts. If these faults are not detected and dealt with in a timely manner, they may lead to equipment damage, circuit short circuits, or even safety accidents.

[0003] Existing technology, such as the invention patent application with publication number CN111361421A, discloses a new energy vehicle power management system, including a low-voltage power distribution unit, a high-voltage power distribution unit, an insulation monitoring module, a DC-DC conversion module, and a power management controller. The low-voltage power distribution unit includes relays and fuses. The high-voltage power distribution unit includes high-voltage relays, high-voltage contactors, high-voltage fuses, and high-voltage connectors. The detection terminals of the insulation monitoring module are connected to the positive and negative terminals of the high-voltage circuit of the high-voltage power distribution unit and the system ground. The DC-DC conversion module has its high-voltage input terminal connected to the high-voltage connector, and its low-voltage power output terminal connected to the low-voltage input terminal of the low-voltage power distribution unit. The power management controller communicates with other components of the vehicle via a CAN bus. This invention features high integration, comprehensive functions, high reliability, and convenient vehicle layout; it facilitates fault diagnosis and maintenance; it has high reliability and strong anti-interference capabilities; it can independently determine high and low voltage faults of external components and disconnect high and low voltage circuits with high authority, ensuring the safety of personnel and the entire vehicle.

[0004] As can be seen from the above solutions, existing fault detection methods for high and low voltage DC contactors mostly adopt single signal detection, such as only detecting coil current or main contact voltage. This results in incomplete detection and a high rate of false fault diagnosis. Some detection devices lack electrical isolation design, which can easily lead to signal interference in high and low voltage coexistence scenarios, resulting in decreased detection accuracy or even damage to the detection circuit. At the same time, existing devices can only realize fault alarms and cannot accurately locate the fault type, which brings great inconvenience to later maintenance. Moreover, the response speed is slow and it is difficult to meet the needs of real-time online detection. Summary of the Invention

[0005] To address the aforementioned technical shortcomings, the present invention aims to provide a fault detection device for high and low voltage DC contactors.

[0006] To solve the above technical problems, the present invention adopts the following technical solution: The present invention provides a high and low voltage DC contactor fault detection device, including the following modules: Parameter acquisition module: used to classify coil current parameters, main contact voltage parameters, auxiliary contact status parameters and circuit on / off parameters for a single high and low voltage DC contactor according to electrical attribute type, and to acquire various control parameters of the contactor in real time using multi-channel electrical detection equipment.

[0007] Model building module: used to extract control parameters of each link in the contactor fault determination, build a dynamic evaluation model of control parameters and fault status, and calculate the comprehensive index of contactor fault risk.

[0008] Fault determination module: It is used to input the real-time collected control parameters into the control parameter-fault state dynamic evaluation model, calculate the control parameter difference rate by comparing various control parameters with the corresponding safety thresholds, obtain the comprehensive difference rate by combining the built-in control parameter difference rate and comprehensive difference rate mapping table, and finally determine the actual operating status of the contactor based on the comprehensive fault risk index threshold, and output the determination result and core abnormal value.

[0009] Fault handling module: After the fault handling is completed, the contactor control parameters are retested and the contactor operating status is reassessed. The detection process is optimized for abnormal fault judgment links and corresponding control parameters.

[0010] The beneficial effects of this invention are as follows: This invention provides a fault detection device for high and low voltage DC contactors. For a single high and low voltage DC contactor, it first classifies electrical attributes into coil current, main contact voltage, auxiliary contact status, and circuit continuity. Real-time data is collected using multi-channel electrical detection equipment. Then, parameters from the fault determination process are extracted to construct a dynamic evaluation model of control parameters and fault status, and a comprehensive fault risk index is calculated. The real-time collected parameters are substituted into the model, and the difference rate is calculated and compared with a threshold to determine the operating status, outputting the results and core anomalies. Finally, after fault handling, the parameters are retested, and the detection process for abnormal links is optimized. This invention, through quantitative determination based on a dynamic evaluation model and retesting and optimization after fault handling, achieves accurate detection of the contactor's operating status and effective fault handling, significantly improving the accuracy of fault detection and the reliability of contactor operation. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1This is a schematic diagram of the system structure connection of the present invention. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] See Figure 1 As shown, a fault detection device for high and low voltage DC contactors includes the following modules: Parameter acquisition module: used to classify the electrical attribute type of a single high and low voltage DC contactor into coil current parameters, main contact voltage parameters, auxiliary contact status parameters and circuit on / off parameters, and to acquire various control parameters of the contactor in real time using multi-channel electrical detection equipment.

[0015] In a specific embodiment, the parameter acquisition module performs the following process: for the acquisition of coil current, main contact voltage and auxiliary contact status control parameters, continuous acquisition is performed with the single on / off cycle of the contactor as the acquisition unit, and the acquisition frequency is not less than once per millisecond; for the circuit on / off control parameters, a batch acquisition method is adopted, and the frequency of batch acquisition matches the contactor operation cycle monitoring cycle. During the acquisition process, the acquisition time and corresponding detection point of various control parameters are recorded synchronously.

[0016] It should be noted that the coil current parameter refers to the current value, trend of change, and stability parameters of the high and low voltage DC contactor coil during the processes of energization, engagement, holding, and de-energization.

[0017] Main contact voltage parameters: These refer to the voltage values ​​across the main contacts of the high and low voltage DC contactor, the contact voltage drop, and the voltage state parameters during disconnection.

[0018] Auxiliary contact status parameters: refer to the on / off status, action sequence, and signal feedback status parameters of the auxiliary contacts of high and low voltage DC contactors.

[0019] Circuit on / off parameters: These refer to the on / off state and on / off reliability parameters of the main circuit and control circuit where the contactor is located.

[0020] Model building module: used to extract control parameters of each link in the contactor fault determination, build a dynamic evaluation model of control parameters and fault status, and calculate the comprehensive index of contactor fault risk.

[0021] In a specific embodiment, the test preparation setting process for constructing the control parameter-fault state dynamic evaluation model is as follows: construct a 1:1 standard simulated operating environment based on the actual operating electrical environment of the high and low voltage DC contactor, and obtain the safety thresholds of coil current parameters, main contact voltage parameters, auxiliary contact state parameters and circuit on / off parameters from the contactor design stage.

[0022] In a standard simulation environment, a control group and four types of control parameter experiments were set up. In the control group, all types of control parameters were within the safe threshold range. The four types of control parameter experiments were coil current experiments, main contact voltage experiments, auxiliary contact status experiments, and circuit on / off experiments. Multiple experimental groups were set up under each type of control parameter experiment. Each experimental group of each type of control parameter experiment had one type of control parameter as the independent variable that exceeded the safe threshold. The other types of control parameters were kept consistent with the control group. The independent variable was tested in multiple groups in a gradient-increasing manner.

[0023] Both the control group and the experimental group were set up as test groups with the same basic contactor specifications. Only one type of control parameter had a setting difference before the fault detection process was carried out.

[0024] It should be noted that the safety threshold is the range or benchmark value of various control parameters obtained from the contactor design stage that ensures its safe and stable operation. It is used to determine whether the control parameters are within the normal and safe range. Parameters within the threshold are considered normal, while those exceeding the threshold are considered abnormal.

[0025] Preferably, the specific process of the fault detection procedure is as follows: the control group and all experimental groups are placed in a standard simulated operating environment, and an electrical operation simulation test is conducted using a power supply system that matches the actual operating circuit of the contactor. The detection status standard indicators of the control group and the detection status indicators of each experimental group are detected simultaneously. The detection status indicators include fault location accuracy, fault response timeliness, and fault false alarm rate. The fault location accuracy is obtained through electrical testing instruments, the fault response timeliness is obtained through timing by a data acquisition terminal, and the fault false alarm rate is obtained by statistically comparing the total number of faults that actually occur in the contactor with the number of faults that the detection device fails to identify.

[0026] After detection, the detection status of each experimental group was rated and divided into three levels: excellent, medium and poor. The gradient value of the independent variable under the experiment of the control parameter for the experimental group with poor status is the initial outlier value of the experiment, that is, the value of the deviation from the safety threshold corresponding to the first occurrence of the poor status of the control parameter. The parameter difference between each outlier value and the control parameter of the control group was recorded simultaneously to generate the basic data of fault detection status corresponding to different gradient independent variables under the experiment of various control parameters, which serves as the basic training data for model construction.

[0027] It should be noted that the fault location accuracy parameter is calculated by comparing the judgment results of the detection device with the actual fault situation of the contactor, combined with the measured data of electrical testing instruments and fault verification equipment. Fault location accuracy = (number of times the fault was correctly located ÷ total number of times the fault was identified) × 100%.

[0028] Fault response timeliness parameter: refers to the time from the occurrence of a contactor fault to the detection device recognizing and outputting a fault signal, which is obtained through timing by the data acquisition terminal.

[0029] Fault underreporting rate parameter: The total number of faults that actually occurred in the contactor is statistically compared with the number of faults that were not identified by the detection device. Combined with the actual fault verification data and the device fault judgment record, the fault underreporting rate = (number of underreported faults ÷ total number of actual faults of the contactor) × 100%.

[0030] Preferably, the specific process of constructing the control parameter-fault state dynamic evaluation model is as follows: retrieve the detection data of each experimental group under various control parameter experiments, the control parameters of the control group, and the standard indicators of detection status from the database, calculate the control parameter difference rate of the abnormal value in each experimental group under various control parameter experiments relative to the control parameter of the control group, and the calculation formula is: control parameter difference rate = |actual detection value - control parameter value of the control group| ÷ control parameter value of the control group.

[0031] Calculate the single-index difference rate of the detection status index of each gradient experimental group under various control parameters relative to the standard detection status index of the control group. The single-index difference rate = |actual detection status index value - standard detection status index value| ÷ standard detection status index value. Assign weights based on the importance of each detection status index, with fault location accuracy 0.5, fault response timeliness 0.3, and fault false alarm rate 0.2. The weighted calculation yields the comprehensive difference rate = fault location accuracy difference rate × 0.5 + fault response timeliness difference rate × 0.3 + fault false alarm rate difference rate × 0.2.

[0032] A mapping table between the control parameter difference rate and the comprehensive difference rate under various control parameter experiments was established. The comprehensive difference rate was divided into three levels: excellent state, medium state, and poor state, corresponding to the ranges of 0-0.2, 0.2-0.7, and 0.7-1.0, respectively. The comprehensive fault risk index thresholds corresponding to each level were set: excellent state ≤ 0.2, medium state 0.2-0.7, and poor state > 0.7, forming a dynamic evaluation model of control parameters-fault state.

[0033] It should be noted that the control parameter difference rate is an indicator used to quantify the deviation of the experimental group's outlier value from the control group's safety threshold. The larger the value, the more serious the deviation of the outlier value from the standard. The calculation formula is: Control parameter difference rate = |Actual detected value - Control group control parameter value| ÷ Control group control parameter value.

[0034] Detection status indicators: These are three core indicators that represent the effectiveness of contactor fault detection, including fault location accuracy, fault response timeliness, and fault false alarm rate. They are key parameters for evaluating the effectiveness of the detection system.

[0035] Single index difference rate: For a single type of detection status parameter, the index that quantifies the deviation of the experimental group from the baseline value of the control group is calculated by the following formula: Single index difference rate = |Actual detection status index value - Standard detection status index value| ÷ Standard detection status index value.

[0036] Overall Difference Rate: The overall difference index is calculated by weighting the individual index differences of the three types of detection status parameters (fault location accuracy, fault response timeliness, and fault false alarm rate) according to preset weights. The calculation formula is: Overall Difference Rate = Fault Location Accuracy Difference Rate × 0.5 + Fault Response Timeliness Difference Rate × 0.3 + Fault False Alarm Rate Difference Rate × 0.2. The larger the value, the more serious the overall deviation of the detection status from the benchmark.

[0037] The comprehensive fault risk index threshold is a critical value used to determine the actual operating status of high and low voltage DC contactors. It is set based on the comprehensive difference rate level classification under various control parameter experiments. Its range has a one-to-one correspondence with the comprehensive fault risk index and the contactor's operating status. The comprehensive fault risk index ranges from 0 to 1. The larger the value, the higher the overall fault risk of the contactor and the worse the operating status. The specific classification is as follows: Comprehensive difference rate 0-0.2 (excellent status): Comprehensive fault risk index ≤ 0.2 indicates that the deviation of various control parameters of the contactor from the standard reference value is extremely small, the detection status is optimal, and there is no fault risk; Comprehensive difference rate 0.2-0.7 (medium status): Comprehensive fault risk index 0.2-0.7 indicates that some control parameters of the contactor have moderate deviations, the detection status is average, and there is a critical fault risk; Comprehensive difference rate 0.7-1.0 (poor status): Comprehensive fault risk index > 0.7 indicates that the core control parameters of the contactor have serious deviations, the detection status is extremely poor, and there is a severe fault risk.

[0038] Preferably, the specific process for calculating the comprehensive index of contactor fault risk is as follows: the actual values ​​of various control parameters collected in real time are compared one by one with the safety thresholds of control parameters preset in the contactor design stage, and abnormal values ​​exceeding the safety thresholds are screened out; the control parameter difference rate of each group of abnormal values ​​under each type of control parameter experiment is calculated, the control parameter difference rate is input into the control parameter-fault state dynamic evaluation model, and the comprehensive difference rate corresponding to each group of abnormal values ​​under various types of control parameter experiments is obtained through the built-in mapping table of control parameter difference rate and comprehensive difference rate.

[0039] Based on the comprehensive difference rate of outliers in each group under each type of control parameter experiment, the comprehensive fault risk index is calculated using the following formula: In the formula This represents the comprehensive index of failure risk. Indicates the first Class of control parameter experiment The weighting coefficients for each outlier Indicates the first Class of control parameter experiment The overall difference rate of each outlier Indicates the subscript for the control parameter experimental type. =1, 2, 3, 4 correspond to coil current, main contact voltage, auxiliary contact status, and circuit continuity experiments, respectively; Indicates the first Outlier indices under control parameter experiments; Indicates the first The number of outliers in the class-controlled parameter experiment, and the number of outliers in the single-class experiment. =0; , and It is a positive integer.

[0040] It should be noted that the first Class of control parameter experiment The weighting coefficients of each outlier are as follows: (1) Based on the importance of the parameters: the basic weights are set according to the degree of influence of various control parameters on the safe operation of the contactor. For example, the coil current parameter is the core power parameter for the contactor to engage and hold. An abnormality may directly cause the contactor to fail to operate. The basic weight can be set to 0.35. The main contact voltage parameter directly reflects the reliability of the main circuit. An abnormality may easily cause short circuits and equipment damage. The basic weight can be set to 0.3. The auxiliary contact status parameter affects the accuracy of signal feedback. The basic weight can be set to 0.2. The circuit connection parameter reflects the overall circuit reliability. The basic weight can be set to 0.15. (2) Based on the severity of the abnormality: for multiple outliers under the same type of experiment, the weights are adjusted according to the difference rate of the control parameters (the degree of deviation from the standard value): the difference rate of the control parameters ≥ 0.7 (serious abnormality): the basic weight of the parameter is increased by 20%; the difference rate of the control parameters 0.2-0.7 (moderate abnormality): the basic weight of the parameter is maintained; the difference rate of the control parameters < 0.2 (mild abnormality): the basic weight of the parameter is reduced by 20%.

[0041] Fault determination module: It is used to input the real-time collected control parameters into the control parameter-fault state dynamic evaluation model, calculate the control parameter difference rate by comparing various control parameters with the corresponding safety thresholds, obtain the comprehensive difference rate by combining the built-in control parameter difference rate and comprehensive difference rate mapping table, and finally determine the actual operating status of the contactor based on the comprehensive fault risk index threshold, and output the determination result and core abnormal value.

[0042] In a specific embodiment, the fault determination module performs the following process: it substitutes the real-time collected actual values ​​of various control parameters into the control parameter-fault state dynamic evaluation model, compares them one by one with the preset control parameter safety threshold range in the model, and selects control parameters that exceed the threshold range as actual detected abnormal values.

[0043] For the selected actual outliers, the control parameter difference rate is calculated using the following formula: |Actual Detection Value - Control Parameter Value of Control Group| ÷ Control Parameter Value of Control Group, where the control parameter value of the control group is the baseline parameter value of the control group in the standard simulation environment during the model building phase.

[0044] The calculated control parameter difference rate of the actual detected anomaly value is matched with the control parameter difference rate-comprehensive difference rate mapping table built into the model to obtain the comprehensive difference rate corresponding to each actual detected anomaly value. Then, based on the weight coefficients preset by the model, the comprehensive fault risk index of the contactor is calculated to determine the actual operating status of the contactor.

[0045] It should be noted that the actual detected abnormal values ​​are those values ​​of the control parameters collected in real time that exceed the safety threshold range of the contactor control parameters. According to the parameter type, they can be divided into actual detected abnormal values ​​of coil current and actual detected abnormal values ​​of main contact voltage, etc.

[0046] Preferably, the specific process for determining the actual operating status of the contactor is as follows: compare the actual calculated comprehensive fault risk index with the threshold range of the comprehensive fault risk index preset by the model; if the comprehensive fault risk index is ≤0.2, the contactor is determined to be in normal operating status.

[0047] When the comprehensive fault risk index is between 0.2 and 0.7 or greater than 0.7, the contactor is determined to be in an abnormal operating state. For contactors determined to be abnormal, all actual detected abnormal values ​​and their corresponding control parameter difference rates and comprehensive difference rates are extracted from the database. The abnormal values ​​are sorted from high to low according to the comprehensive difference rate, and the actual detected abnormal values ​​with a comprehensive difference rate ≥ 0.7 are selected as the core abnormal values.

[0048] The system outputs the judgment conclusion of the abnormal operation status of the contactor, and synchronously outputs the control parameter experiment type to which the core abnormal value belongs, the control parameter difference rate of each core abnormal value, and the corresponding comprehensive difference rate.

[0049] It should be noted that the core outlier is the key parameter with the highest impact on the contactor's fault status, selected from all actual detected outliers. The selection criterion is "overall difference rate ≥ 0.7", which is the core cause of abnormal contactor operation.

[0050] Judgment conclusion: Based on the comparison between the comprehensive fault risk index and the threshold range of the comprehensive fault risk index, the qualitative judgment result of the contactor's operating status includes only two categories: "normal operating status" and "abnormal operating status".

[0051] Fault handling module: After the fault handling is completed, the contactor control parameters are retested and the contactor operating status is reassessed. The detection process is optimized for abnormal fault judgment links and corresponding control parameters.

[0052] In a specific embodiment, the fault handling module performs the following process: after the actual operating state of the contactor is determined to be abnormal, the corresponding fault-related link is directly located based on the control parameter type to which the core abnormal value belongs, and a fault handling operation is performed on that link.

[0053] After the fault is resolved, the actual values ​​of various control parameters of the contactor are collected again in real time to recalculate the comprehensive fault risk index and determine whether the contactor's operating status has returned to normal.

[0054] Simultaneously calculate the overall difference rate deviation between the core abnormal value after fault handling and before handling. The formula is: Overall difference rate deviation = |Overall difference rate after handling - Overall difference rate before handling| ÷ Overall difference rate before handling. If the contactor is re-determined to be operating normally and the overall difference rate deviation of the core abnormal value is ≤0.1, it indicates that the fault has been effectively resolved, and this optimization step ends.

[0055] If the contactor is still determined to be abnormal, or the overall difference rate deviation of the core abnormal value is >0.1, then the detection process of the fault-related link corresponding to the core abnormal value is optimized. After adjusting the process parameters, the above collection, judgment and processing steps are repeated until the actual operating status of the contactor returns to normal and the overall difference rate deviation of the core abnormal value is ≤0.1.

[0056] It should be noted that the overall difference rate deviation value is an indicator that quantifies the change in the degree of influence of core anomalies before and after fault handling. The calculation formula is: Overall difference rate deviation value = |Overall difference rate after handling - Overall difference rate before handling| ÷ Overall difference rate before handling. The larger the overall difference rate deviation value, the more significant the decrease in the degree of influence of core anomalies after fault handling. Combined with the operation status judgment results, it can accurately determine whether the fault has been effectively resolved.

[0057] Process parameters: These refer to the core technical indicators and operating parameters that need to be strictly controlled during the execution of the testing process. They are the specific adjustment objects for the systematic optimization of the testing process, such as current sampling frequency, voltage detection calibration coefficient, and loop detection cycle.

[0058] The contactor’s actual operating status has returned to normal: This means that after the fault is handled, the contactor is verified by both key monitoring data and overall monitoring data and meets two core standards: (1) the recalculated comprehensive fault risk index is ≤0.2; (2) the comprehensive difference rate deviation of core abnormal values ​​is ≤0.1, indicating that the fault handling is effective and the detection system is working normally as a whole.

[0059] The database is used to store various control parameters, detection status indicators, control parameter difference rates, comprehensive difference rates, comprehensive fault risk index, and basic data on fault detection status. It is also used to store safety thresholds and comprehensive fault risk index thresholds.

[0060] The examples described in this invention are not limited to the specific embodiments listed above. The examples are merely illustrative to facilitate understanding of the invention and do not constitute a limitation on the scope of protection of this invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of this invention should be included within the scope of protection.

[0061] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in this specification, they should all fall within the protection scope of the present invention.

Claims

1. A fault detection device for high and low voltage DC contactors, characterized in that, Includes the following modules: Parameter acquisition module: Used for a single high and low voltage DC contactor, it classifies the parameters into coil current parameters, main contact voltage parameters, auxiliary contact status parameters and circuit on / off parameters according to electrical attribute type, and uses multi-channel electrical detection equipment to acquire various control parameters of the contactor in real time; Model building module: used to extract control parameters of each link in the contactor fault determination, build a dynamic evaluation model of control parameters and fault status, and calculate the comprehensive index of contactor fault risk; Fault determination module: It is used to input the real-time collected control parameters into the control parameter-fault state dynamic evaluation model, calculate the control parameter difference rate by comparing various control parameters with the corresponding safety thresholds, obtain the comprehensive difference rate by combining the built-in control parameter difference rate and comprehensive difference rate mapping relationship table, and finally determine the actual operating status of the contactor based on the comprehensive fault risk index threshold, and output the determination result and core abnormal value. Fault handling module: After the fault handling is completed, the contactor control parameters are retested and the contactor operating status is reassessed. The detection process is optimized for abnormal fault judgment links and corresponding control parameters.

2. The high and low voltage DC contactor fault detection device according to claim 1, characterized in that, The specific process of the parameter acquisition module is as follows: For the acquisition of coil current, main contact voltage and auxiliary contact status control parameters, continuous acquisition is performed using the single on / off cycle of the contactor as the acquisition unit, with an acquisition frequency of no less than once per millisecond; for circuit on / off control parameters, a batch acquisition method is adopted, and the batch acquisition frequency matches the contactor operation cycle monitoring cycle. During the acquisition process, the acquisition time and corresponding detection point of various control parameters are recorded synchronously.

3. The high and low voltage DC contactor fault detection device according to claim 1, characterized in that, The specific process for test preparation settings for constructing the control parameter-fault state dynamic evaluation model is as follows: Based on the actual operating electrical environment of high and low voltage DC contactors, a 1:1 standard simulated operating environment is constructed to obtain the safety thresholds of coil current parameters, main contact voltage parameters, auxiliary contact status parameters, and circuit on / off parameters from the contactor design stage. In a standard simulation environment, a control group and four types of control parameter experiments were set up. In the control group, all types of control parameters were within the safe threshold range. The four types of control parameter experiments were coil current experiments, main contact voltage experiments, auxiliary contact status experiments, and circuit continuity experiments. Multiple experimental groups were set up under each type of control parameter experiment. Each experimental group of each type of control parameter experiment had one type of control parameter as the independent variable and exceeded the safe threshold. The other types of control parameters were kept consistent with the control group. The independent variable was tested in multiple groups in a gradient-increasing manner. Both the control group and the experimental group were set up as test groups with the same basic contactor specifications. Only one type of control parameter had a setting difference before the fault detection process was carried out.

4. The high and low voltage DC contactor fault detection device according to claim 3, characterized in that, The specific process for performing the fault detection procedure is as follows: The control group and all experimental groups were placed in a standard simulated operating environment and electrical operation simulation tests were conducted using a power supply system that matched the actual operating circuit of the contactor. The detection status standard indicators of the control group and the detection status indicators of each experimental group were detected simultaneously. The detection status indicators included fault location accuracy, fault response timeliness and fault false alarm rate. Fault location accuracy is obtained through electrical testing instruments, fault response timeliness is obtained through data acquisition terminal timing, and fault false alarm rate is obtained by statistically comparing the total number of faults actually occurring in the contactor with the number of faults not identified by the detection device. After detection, the detection status of each experimental group was rated and divided into three levels: excellent, medium and poor. The gradient value of the independent variable under the experiment of the control parameter for the experimental group with poor status is the initial outlier value of the experiment, that is, the value of the deviation from the safety threshold corresponding to the first occurrence of the poor status of the control parameter. The parameter difference between each outlier value and the control parameter of the control group was recorded simultaneously to generate the basic data of fault detection status corresponding to different gradient independent variables under the experiment of various control parameters, which serves as the basic training data for model construction.

5. A high- and low-voltage DC contactor fault detection device according to claim 4, characterized in that, The specific process for constructing the control parameter-fault state dynamic evaluation model is as follows: The database is used to retrieve the detection data of each experimental group under various control parameters, the control parameters of the control group, and the standard indicators of the detection status. The control parameter difference rate of the outliers in each experimental group under various control parameters is calculated relative to the control parameters of the control group. The calculation formula is: Control parameter difference rate = |actual detection value - control parameter value of the control group| ÷ control parameter value of the control group. Calculate the single-index difference rate of the detection status index of each gradient experimental group under various control parameters relative to the standard index of the control group. The single-index difference rate is: |actual detection status index value - standard detection status index value| ÷ standard detection status index value. Weights are assigned based on the importance of each detection status indicator, with fault location accuracy at 0.5, fault response timeliness at 0.3, and fault false alarm rate at 0.

2. The weighted calculation yields the comprehensive difference rate = fault location accuracy difference rate × 0.5 + fault response timeliness difference rate × 0.3 + fault false alarm rate difference rate × 0.

2. A mapping table between the control parameter difference rate and the comprehensive difference rate under various control parameter experiments was established. The comprehensive difference rate was divided into three levels: excellent state, medium state, and poor state, corresponding to the ranges of 0-0.2, 0.2-0.7, and 0.7-1.0, respectively. The comprehensive fault risk index thresholds corresponding to each level were set: excellent state ≤ 0.2, medium state 0.2-0.7, and poor state > 0.7, forming a dynamic evaluation model of control parameters-fault state.

6. A high- and low-voltage DC contactor fault detection device according to claim 5, characterized in that, The specific process for calculating the comprehensive index of contactor failure risk is as follows: The actual values ​​of various control parameters collected in real time are compared one by one with the safety thresholds of control parameters preset during the contactor design stage, and abnormal values ​​that exceed the safety thresholds are filtered out. Calculate the control parameter difference rate of each group of outliers under each type of control parameter experiment, input the control parameter difference rate into the control parameter-fault state dynamic evaluation model, and obtain the comprehensive difference rate corresponding to each group of outliers under each type of control parameter experiment through the built-in control parameter difference rate and comprehensive difference rate mapping table of the model. Based on the comprehensive difference rate of outliers in each group under each type of control parameter experiment, the comprehensive fault risk index is calculated using the following formula: In the formula This represents the comprehensive index of failure risk. Indicates the first Class of control parameter experiment The weighting coefficients of each anomaly detection parameter. Indicates the first Class of control parameter experiment The overall difference rate of each outlier Indicates the subscript for the control parameter experimental type. =1, 2, 3, 4 correspond to coil current, main contact voltage, auxiliary contact status, and circuit continuity experiments, respectively; Indicates the first Outlier indices under control parameter experiments; Indicates the first The number of outliers in the class-controlled parameter experiment, and the number of outliers in the single-class experiment. =0; , and It is a positive integer.

7. A high- and low-voltage DC contactor fault detection device according to claim 1, characterized in that, The specific process of the fault determination module is as follows: The actual values ​​of various control parameters collected in real time are substituted into the dynamic evaluation model of control parameters-fault status, and compared with the preset safety threshold range of control parameters in the model one by one. Control parameters that exceed the threshold range are selected as actual abnormal values. For the selected actual outliers, the control parameter difference rate is calculated using the following formula: |Actual detected value - Control parameter value of control group| ÷ Control parameter value of control group, where the control parameter value of control group is the baseline parameter value of the control group in the standard simulation environment during the model building phase. The calculated control parameter difference rate of the actual detected anomaly value is matched with the control parameter difference rate-comprehensive difference rate mapping table built into the model to obtain the comprehensive difference rate corresponding to each actual detected anomaly value. Then, based on the weight coefficients preset by the model, the comprehensive fault risk index of the contactor is calculated to determine the actual operating status of the contactor.

8. A high- and low-voltage DC contactor fault detection device according to claim 7, characterized in that, The specific process for determining the actual operating status of the contactor is as follows: Compare the actual calculated comprehensive fault risk index with the threshold range of the comprehensive fault risk index preset by the model. If the comprehensive fault risk index is ≤0.2, the contactor is determined to be in normal operating condition. When the comprehensive fault risk index is between 0.2 and 0.7 or greater than 0.7, the contactor is determined to be in an abnormal operating state. For contactors identified as abnormal, all actual detected abnormal values ​​and their corresponding control parameter difference rates and overall difference rates are extracted from the database. The values ​​are sorted from high to low according to the overall difference rate, and actual detected abnormal values ​​with an overall difference rate ≥ 0.7 are selected as core abnormal values. The system outputs the judgment conclusion of the abnormal operation status of the contactor, and synchronously outputs the control parameter experiment type to which the core abnormal value belongs, the control parameter difference rate of each core abnormal value, and the corresponding comprehensive difference rate.

9. A high- and low-voltage DC contactor fault detection device according to claim 1, characterized in that, The specific process of the fault handling module is as follows: Once the actual operating status of the contactor is determined to be abnormal, the corresponding fault-related link is directly located based on the control parameter type to which the core abnormal value belongs, and fault handling operations are performed on that link. After the fault is resolved, the actual values ​​of various control parameters of the contactor are collected again in real time to recalculate the comprehensive fault risk index and determine whether the contactor's operating status has returned to normal. Simultaneously calculate the overall difference rate deviation between the core abnormal value after fault handling and before handling. The formula is: Overall difference rate deviation = |Overall difference rate after handling - Overall difference rate before handling| ÷ Overall difference rate before handling. If the contactor is re-determined to be operating normally and the overall difference rate deviation of the core abnormal value is ≤0.1, it indicates that the fault has been effectively resolved, and this optimization step ends. If the contactor is still determined to be abnormal, or the overall difference rate deviation of the core abnormal value is >0.1, then the detection process of the fault-related link corresponding to the core abnormal value is optimized. After adjusting the process parameters, the above collection, judgment and processing steps are repeated until the actual operating status of the contactor returns to normal and the overall difference rate deviation of the core abnormal value is ≤0.

1.

10. A high- and low-voltage DC contactor fault detection device according to claim 1, characterized in that, The database is used to store various control parameters, detection status indicators, control parameter difference rates, comprehensive difference rates, comprehensive fault risk index, and basic data on fault detection status. It is also used to store safety thresholds and comprehensive fault risk index thresholds.

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