Method and device for determining health degree of direct current contactor and electronic equipment

Abstract

The invention discloses a method and device for determining the health degree of a direct current contactor and electronic equipment. The method comprises the following steps: acquiring historical life data of the DC contactor; determining initial accumulated damage of the direct current contactor based on the historical life data; based on a single loss environmental influence coefficient, the initial accumulated damage is corrected, target accumulated damage of the direct current contactor is obtained, and the single loss environmental influence coefficient is used for reflecting the loss degree of the direct current contactor caused by environmental factors when the direct current contactor executes closing or opening operation; and determining the health degree of the DC contactor based on the target accumulated damage. The technical problem that the accuracy of the health degree determination result of the direct current contactor is low in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of power systems, and more specifically, to a method, apparatus, and electronic device for determining the health status of a DC contactor. Background Technology

[0002] DC contactors for new energy vehicles are mainly used in charging piles and electric vehicles. In charging piles, the closing of the DC contactor acts as a "bridge," connecting the charging pile and the electric vehicle. The closing of the DC contactor effectively protects the safety of both the charging pile and the electric vehicle. As one of the basic electrical components of charging equipment, the DC contactor in charging piles operates in complex environments, has diverse forms, and frequently exceeds its lifespan. The main reason for the excessive lifespan of DC contactors in charging piles is the lack of direct and simple methods for detecting their health and predicting their lifespan. The core issue in studying the health status of DC contactors in charging piles is determining their electrical lifespan. The electrical lifespan of a DC contactor can be determined by assessing its cumulative damage. However, the state parameters used in related technologies to characterize cumulative damage are mostly cumulative arc energy, release time, and release voltage, which can only be collected under specific equipment or high sampling frequencies. This poses a significant challenge to the real-time detection and accurate determination of cumulative damage in DC contactors, resulting in unsatisfactory accuracy in determining the health status of DC contactors in charging piles.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This application provides a method, apparatus, and electronic device for determining the health status of a DC contactor, in order to at least solve the technical problem of low accuracy in determining the health status of DC contactors in related technologies.

[0005] According to one aspect of the embodiments of this application, a method for determining the health of a DC contactor is provided, comprising: acquiring historical life data of the DC contactor; determining the initial cumulative damage of the DC contactor based on the historical life data; correcting the initial cumulative damage based on a single-loss environmental impact coefficient to obtain a target cumulative damage of the DC contactor, wherein the single-loss environmental impact coefficient is used to reflect the degree of wear and tear on the DC contactor by environmental factors when the DC contactor performs a closing or opening operation; and determining the health of the DC contactor based on the target cumulative damage.

[0006] According to another aspect of the embodiments of this application, a device for determining the health of a DC contactor is provided, comprising: a data acquisition module for acquiring historical life data of the DC contactor; an initial cumulative damage determination module for determining the initial cumulative damage of the DC contactor based on the historical life data; a target cumulative damage determination module for correcting the initial cumulative damage based on a single-loss environmental impact coefficient to obtain the target cumulative damage of the DC contactor, wherein the single-loss environmental impact coefficient is used to reflect the degree of wear and tear on the DC contactor by environmental factors when the DC contactor performs a closing or opening operation; and a health determination module for determining the health of the DC contactor based on the target cumulative damage.

[0007] According to another aspect of the embodiments of this application, a non-volatile storage medium is provided, which stores a plurality of instructions adapted for a method for determining the health of a DC contactor, any one of which is loaded by a processor.

[0008] According to another aspect of the embodiments of this application, an electronic device is provided, including: one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement any one of the following methods for determining the health of a DC contactor.

[0009] In this embodiment, historical lifespan data of a DC contactor is acquired; based on this data, the initial cumulative damage of the DC contactor is determined; the initial cumulative damage is corrected using a single-loss environmental impact coefficient to obtain the target cumulative damage of the DC contactor. The single-loss environmental impact coefficient reflects the degree of wear and tear on the DC contactor caused by environmental factors during closing or opening operations; and the health status of the DC contactor is determined based on the target cumulative damage. This achieves the goal of determining the initial cumulative damage of the DC contactor based on its historical lifespan data and correcting it using the single-loss environmental impact coefficient to obtain the target cumulative damage. This improves the accuracy of the health status determination results for the DC contactor, thereby solving the technical problem of low accuracy in determining the health status of DC contactors in related technologies. Attached Figure Description

[0010] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0011] Figure 1 This is a flowchart of an optional method for determining the health of a DC contactor according to an embodiment of this application;

[0012] Figure 2 This is a schematic diagram of an optional experimental platform provided according to an embodiment of this application;

[0013] Figure 3 This is a first schematic diagram of an optional method for determining the health of a DC contactor according to an embodiment of this application;

[0014] Figure 4 This is a second schematic diagram of an optional method for determining the health of a DC contactor according to an embodiment of this application;

[0015] Figure 5 This is a third schematic diagram of an optional method for determining the health of a DC contactor according to an embodiment of this application;

[0016] Figure 6 This is a schematic diagram of an optional DC contactor health determination device provided according to an embodiment of this application. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] According to an embodiment of this application, a method embodiment for determining the health of a DC contactor is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0020] Figure 1 This is a flowchart of an optional method for determining the health of a DC contactor according to an embodiment of this application, such as... Figure 1 As shown, the method includes the following steps:

[0021] Step S102: Obtain historical lifespan data of the DC contactor;

[0022] It is understandable that acquiring historical lifespan data of DC contactors under different operating conditions is crucial, including historical break voltage data, historical segmented current data, electrical life data, and environmental parameters. By collecting this historical lifespan data, the health of DC contactors can be assessed, enabling the development of more effective preventative maintenance strategies, reducing maintenance costs, and extending the service life of the contactors.

[0023] Optionally, the above embodiments can be used to assess and determine the health status of the output contactor of the charging pile. The aforementioned output contactor refers to a DC contactor located at the output end of the charging pile, used to control the connection between the charging pile and the electric vehicle.

[0024] Step S104: Based on historical life data, determine the initial cumulative damage of the DC contactor;

[0025] Understandably, based on historical lifespan data of DC contactors, multiple individual damages under different conditions are identified. These individual damages are then accumulated to obtain the initial cumulative damage of the DC contactor. By determining the initial cumulative damage, the health of the DC contactor can be accurately assessed, thereby enabling preventative maintenance and fault prediction, and improving the efficiency and safety of the DC contactor.

[0026] In one optional embodiment, determining the initial cumulative damage of the DC contactor based on historical life data includes: determining multiple sets of historical operating data of the DC contactor included in the historical life data, and multiple single damages corresponding to the multiple sets of historical operating data, wherein each set of historical operating data includes historical break voltage data and historical segmented current data, and the multiple sets of historical operating data correspond one-to-one with the multiple single damages; and accumulating the multiple single damages to obtain the initial cumulative damage.

[0027] It is understood that the historical lifespan data of a DC contactor includes multiple sets of historical operating data, each set containing historical break-point voltage data and historical segmented current data. Based on the historical break-point voltage and segmented current data included in each set of historical operating data, the single-instance damage corresponding to each set of historical operating data is determined, thus obtaining multiple single-instance damages. These multiple single-instance damages are accumulated to obtain the initial cumulative damage of the DC contactor. By accumulating multiple single-instance damages, the degree of damage accumulation of the DC contactor can be quantified, providing basic data for predicting the remaining electrical life of the DC contactor.

[0028] In one optional embodiment, determining multiple sets of historical operating data of the DC contactor included in the historical life data, and multiple single damages corresponding to the multiple sets of historical operating data, includes: fitting the electrical life data, historical break voltage data, and segmented current data of the DC contactor included in the historical life data to obtain a bivariate function model of the DC contactor, wherein the bivariate function model is used to reflect the bivariate function relationship between the electrical life of the DC contactor and the break voltage and segmented current; determining the single erosion amount of the DC contactor contacts, wherein the single erosion amount represents the degree to which the contact material of the DC contactor is removed or damaged during each closing or opening operation; and determining the single damage of the DC contactor using the bivariate function model based on the historical break voltage data, historical segmented current data, and single erosion amount.

[0029] It is understandable that fitting the historical lifespan data, historical break voltage data, and segmented current data of the DC contactor included in the historical lifespan data yields a bivariate function model of the DC contactor. This model represents the trend of the DC contactor's electrical lifespan changing with the break voltage and segmented current. The single-pass erosion amount of the DC contactor's contacts is calculated, representing the degree to which contact material is removed or damaged during each closing or opening operation. Based on the historical break voltage data and historical segmented current data, combined with the single-pass erosion amount of the DC contactor's contacts, the aforementioned bivariate function model is used to determine the single-pass damage of the DC contactor under the given historical break voltage and segmented current data conditions. By establishing a bivariate function mathematical model between the break voltage and breaking current and the contactor's electrical lifespan, the degree of damage caused to the contactor by each operation can be more accurately assessed, thereby improving the accuracy of damage assessment.

[0030] In one optional embodiment, determining the single-pass erosion amount of the contacts of a DC contactor includes: performing an opening test on the DC contactor under rated breaking voltage and rated segmented current conditions to determine the distribution characteristics of the single-pass erosion amount of the contacts of the DC contactor; and determining the single-pass erosion amount based on the distribution characteristics.

[0031] It is understandable that the rated breaking voltage and rated breaking current of a DC contactor are determined. Under these conditions, a breaking test is performed on the DC contactor, and the test data on contact erosion after each breaking operation is recorded. The test data is analyzed and processed to determine the distribution characteristics of the single-pass erosion of the contacts. Based on these distribution characteristics, the single-pass erosion of the DC contactor contacts is determined. Determining the single-pass erosion of the DC contactor contacts through breaking tests allows for a more accurate assessment of the DC contactor's health and electrical life, preventing the DC contactor from operating under unsafe conditions, reducing safety risks caused by DC contactor failures, and ensuring the stable operation of the power grid and charging facilities.

[0032] Alternatively, the amount of contact erosion can be measured in various ways, such as optical measurement, resistance measurement, and weight loss measurement. Optical measurement uses optical microscopy or electron microscopy to observe minute changes on the contact surface, offering high precision and high resolution. The increase in contact resistance is directly proportional to the degree of wear on the contact material. Resistance measurement indirectly assesses contact erosion by measuring the change in resistance of the contactor contact in the closed state, offering simplicity, speed, and wide applicability. Weight loss measurement directly measures the weight change of the contact material after multiple operations to quantify contact erosion, offering directness, accuracy, and high reliability.

[0033] Optionally, the test data recording the contact erosion after each interruption operation is preprocessed, including data cleaning and normalization. The preprocessed test data is then statistically analyzed and modeled to obtain the distribution characteristics of a single erosion event, including distribution fitting and parameter estimation. Distribution fitting refers to using statistical methods (such as normal distribution, Poisson distribution, Weibull distribution, etc.) to fit the preprocessed test data and determine the best-fitting distribution model. Parameter estimation refers to estimating distribution parameters, such as mean, standard deviation, and shape parameters, based on the selected distribution model. These parameters will be used to describe the distribution characteristics of a single erosion event. After completing the statistical analysis and modeling of the preprocessed test data, a distribution description is performed to determine the distribution characteristics of a single erosion event. The aforementioned distribution description refers to using the selected distribution model and parameter estimation results to describe the distribution characteristics of a single erosion event, including the distribution's central location (mean), shape (symmetry, maxima), and range (standard deviation or confidence interval).

[0034] In one optional embodiment, the breaking test of the DC contactor under rated break voltage and rated segmented current conditions includes: constructing an experimental platform, wherein the experimental platform includes a power source, a load, a protection unit, and a control unit; and conducting the breaking test of the DC contactor based on the experimental platform under rated break voltage and rated segmented current conditions.

[0035] It is understandable that to perform breaking tests on DC contactors, an experimental platform for breaking tests needs to be constructed. This platform includes a power source, a load, a protection unit, and a control unit. The power source simulates the charging equipment during normal operation, providing the DC contactor with the rated breaking voltage and rated segmented current. The load simulates the actual power demand during charging and can be a resistive, inductive, or capacitive load. The protection unit protects the experimental platform and operators during testing, including but not limited to overload protection, short-circuit protection, and overvoltage protection, ensuring timely power cut-off in case of abnormal situations to prevent equipment damage or personal injury. The control unit coordinates the entire experimental platform, including controlling the power source output, detecting electrical parameters (such as voltage, current, and arc energy) during the experiment, and recording experimental data. Using this experimental platform, breaking tests are performed on the DC contactor under rated breaking voltage and rated segmented current conditions to determine the distribution characteristics of the single-pass erosion of the DC contactor. By conducting breaking tests on the experimental platform, accurate performance data of the contactor under rated conditions can be obtained, providing a precise data basis for health assessment.

[0036] Optionally, Figure 2 This is a schematic diagram of an optional experimental platform provided according to an embodiment of this application, which can be adopted as follows: Figure 2 The experimental platform shown performs breaking tests on a DC contactor. Figure 2 The experimental platform shown includes a power source, a load, a protection unit, and a control unit. The power source simulates the charging equipment providing the rated break voltage and rated segmented current to the DC contactor during normal operation. The load simulates the actual power demand during charging. The protection unit protects the experimental platform and operators during testing. The control unit coordinates the operation of the experimental platform, including controlling the power source output, detecting electrical parameters (such as voltage, current, and arc energy) during the experiment, and recording experimental data.

[0037] Step S106: Based on the single-loss environmental impact coefficient, the initial cumulative damage is corrected to obtain the target cumulative damage of the DC contactor. The single-loss environmental impact coefficient is used to reflect the degree of damage to the DC contactor caused by environmental factors when the DC contactor performs closing or opening operations.

[0038] It is understandable that the degree of damage to a DC contactor during closing or opening operations is affected by surrounding environmental factors. To improve the accuracy of the target cumulative damage, it is necessary to consider the impact of environmental factors on the DC contactor. A single-loss environmental impact coefficient is determined, and this coefficient is used to correct the initial cumulative damage, yielding the target cumulative damage of the DC contactor. By considering the influence of environmental factors, the corrected target cumulative damage more accurately reflects the true damage state of the contactor, avoiding potential biases in assessments based solely on laboratory conditions or ignoring environmental factors.

[0039] Optionally, the aforementioned environmental factors may include temperature, humidity, vibration, pollution level, electromagnetic interference, etc.

[0040] Optionally, Figure 3 This is a first schematic diagram of an optional method for determining the health of a DC contactor according to an embodiment of this application, as shown below. Figure 3 The diagram illustrates the process for determining the target cumulative damage of a DC contactor. Figure 3 As shown, firstly, the output contactor (i.e., the DC contactor of the charging pile) is subjected to breaking tests under rated voltage and current conditions (i.e., rated break voltage and rated breaking current) until the end of its electrical life, obtaining the distribution characteristics of the single-time erosion of the contacts. Then, the output contactor is subjected to breaking tests under different break voltages and breaking currents until the end of its electrical life, obtaining a bivariate function model of the output contactor's electrical life with respect to break voltage U and breaking current I. Based on the single-time erosion, break voltage U, and breaking current I, the single-time damage 1 / L (dimension 1 / time) of the DC contactor under this break voltage and breaking current is obtained using the bivariate function model. Finally, the break voltage and breaking current at each break of the output contactor are recorded, the single-time damage is calculated, the single-time damage is accumulated, and corrected using the single-time loss environmental impact coefficient, thus obtaining the target cumulative damage L of the output contactor over its life cycle. dmg L dmg It can be obtained in the following way:

[0041]

[0042] Among them, L dmg For the target cumulative damage over the life cycle of the output contactor, L i Let γ represent the single-instance damage under the i-th group of port voltage and breaking current, n be the number of groups of port voltage and breaking current, and γ be the environmental impact coefficient of single-instance loss.

[0043] In an optional embodiment, before correcting the initial cumulative damage based on the single-loss environmental impact coefficient to obtain the target cumulative damage of the DC contactor, the method further includes: normalizing multiple environmental parameters included in the historical life data to obtain standard environmental parameters corresponding to each of the multiple environmental parameters; determining the weighting coefficients corresponding to each of the multiple environmental parameters; and determining the single-loss environmental impact coefficient based on the weighting coefficients corresponding to each of the multiple environmental parameters and the standard environmental parameters corresponding to each of the multiple environmental parameters.

[0044] It is understandable that this involves collecting various environmental parameters from historical lifespan data of DC contactors, cleaning these parameters to remove outliers and fill in any missing values. The cleaned environmental parameters are then normalized to eliminate the influence of numerical differences between parameters, resulting in standard environmental parameters for each parameter. Based on the degree of influence of each environmental parameter on DC contactor damage, weighting coefficients are determined for each parameter. Based on these weighting coefficients and the corresponding standard environmental parameters, a single-loss environmental impact coefficient is determined. By considering the influence of multiple environmental parameters on DC contactor damage and performing normalization, the accuracy and reliability of DC contactor health assessment results can be improved, providing a more scientific basis for the maintenance, design, and resource optimization of charging facilities.

[0045] Step S108: Determine the health status of the DC contactor based on the target cumulative damage.

[0046] It is understandable that the health status of a DC contactor is obtained by using a health assessment model based on the target cumulative damage. By quantifying the relationship between cumulative damage and contactor health status, real-time and accurate assessment of DC contactor health status can be achieved, avoiding the uncertainty of determining DC contactor health status solely based on static parameters or manual inspection.

[0047] In one optional embodiment, determining the health of a DC contactor based on target cumulative damage includes: determining the vibration entropy and contact resistance of the DC contactor, wherein the vibration entropy represents the degree of disorder of the vibration modes of the mechanical components inside the DC contactor, and the contact resistance refers to the resistance between the two contact surfaces of the DC contactor; and obtaining the health level based on the vibration entropy, contact resistance, and target cumulative damage using a health assessment model, wherein the health assessment model has pre-learned the correspondence between the vibration entropy, contact resistance, cumulative damage, and health level of the DC contactor.

[0048] It is understandable that the vibration entropy and contact resistance of a DC contactor need to be determined. Vibration entropy is an indicator that measures the degree of disorder in the vibration modes of the internal mechanical components of the contactor, and is directly related to the mechanical fatigue level of the contactor. Contact resistance is an important parameter for evaluating the electrical performance of the contactor, representing the resistance between the two contact surfaces. An increase in contact resistance usually indicates a more severe wear or corrosion of the contact material. Based on the target cumulative damage, vibration entropy, and contact resistance of the DC contactor, a health assessment model is used to evaluate the health of the DC contactor, thus obtaining the health status. The aforementioned health assessment model pre-learns the correspondence between the vibration entropy, contact resistance, cumulative damage, and health status of the DC contactor. By predicting the health status of the DC contactor, potential faults can be identified in advance, reducing downtime of charging facilities caused by sudden failure of the DC contactor and improving the availability and reliability of the system.

[0049] Optionally, Support Vector Machine (SVM), Random Forest, and Neural Networks (NN) models can be used as health assessment models. These models are trained on large datasets to learn the nonlinear relationship between contactor health and vibration entropy, contact resistance, and cumulative damage. SVM models are trained using labeled datasets and, during training, find a hyperplane (which may be a hyperplane in a high-dimensional feature space) that maximizes the margin between different health states, ensuring the model's generalization ability. Random Forest models integrate the predictions of multiple decision trees to achieve more stable and accurate classification or regression predictions. In health assessment models, Random Forest can handle multidimensional data to evaluate the health of DC contactors, making it suitable for scenarios requiring high accuracy and robustness. Neural Networks provide accurate health assessments and predictions by identifying the complex nonlinear relationships between equipment health and various input data.

[0050] Optionally, but not limited to, a health assessment model can be used to determine the correspondence between the vibration entropy, contact resistance, cumulative damage and health of a DC contactor, as shown in Table 1 below.

[0051] Table 1 Relationship between Cumulative Damage and Health Status

[0052]

[0053] Optionally, a health assessment model based on cumulative damage can be established. This model calculates the single-instance loss (I / L) by online acquisition of the break voltage and breaking current, and continuously accumulates the single-instance damage to obtain the total cumulative damage. Combining historical lifespan data of the output contactor, a cumulative damage model (i.e., a bivariate function model) is established using thin-plate spline interpolation. The single-instance damage is determined by the single-instance erosion of the DC contactor, as well as the break voltage and breaking current on both sides at the breaking point. Accumulating the single-instance damage and combining it with changes in performance parameters (i.e., vibration entropy and contact resistance) yields the health status of the output contactor. When the cumulative lifespan damage value reaches 90%, the vibration entropy increases, and the contact resistance exceeds 1.5 times the level of the stable period, the contactor is considered close to failure and needs replacement.

[0054] Through the above steps S102-S108, the initial cumulative damage of the DC contactor can be determined based on the historical life data of the DC contactor, and the target cumulative damage can be obtained by correcting the initial cumulative damage using the single loss environmental impact coefficient. This achieves the technical effect of improving the accuracy of the health determination result of the DC contactor, and thus solves the technical problem of low accuracy of the health determination result of the DC contactor in related technologies.

[0055] Based on the above embodiments and optional embodiments, this application proposes an optional implementation method for determining the health of the output contactor (i.e., DC contactor) of a charging pile.

[0056] DC contactors for new energy vehicles are mainly used in charging piles and electric vehicles. In charging piles, the closing of the DC contactor acts as a "bridge," connecting the charging pile and the electric vehicle. The closing of the DC contactor effectively protects the safety of both the charging pile and the electric vehicle. Unlike traditional DC contactors, DC contactors for new energy vehicles have stricter requirements for temperature range, vibration resistance, and protection. The normal operating temperature range for DC contactors for new energy vehicles is -20 to 45℃, with a minimum temperature of -40℃ and a maximum temperature of 85℃. For rain protection, the DC contactor for new energy vehicles has an IP67 protection rating, meaning that short-term rain ingress will not affect its normal operation. To cope with different road conditions, DC contactors for new energy vehicles must have a certain degree of vibration resistance to prevent damage from impacts caused by road bumps.

[0057] The performance of components in DC contactors used in new energy vehicles differs from that of traditional DC contactors. For example, the arc-extinguishing chamber material must be heat-resistant, have high mechanical strength, stable chemical properties, corrosion resistance, and high dielectric strength; the terminals must have high conductivity, good weldability, high purity, and corrosion resistance; the magnetic yoke requires corrosion resistance, good oxidation resistance, and high magnetic permeability; the permanent magnet used to accelerate the arc movement must be stable, not easily oxidized, have good dielectric properties, and high magnetic permeability; the arc-extinguishing medium and the arc-extinguishing chamber welding gasket must respectively have stable performance, good arc-extinguishing effect, low coefficient of expansion, and good weldability; and the epoxy materials used for sealing must be resistant to high pressure, impact, aging, high shear and peel strength, high and low temperatures, low coefficient of linear expansion, and high adhesive strength.

[0058] As a fundamental electrical component of charging equipment, the DC contactor in charging piles operates in complex environments with diverse forms, and its use beyond its lifespan is a prominent issue. Fault statistics show that accidents caused by DC contactor failures are frequent and have significant impacts. The excessive use of DC contactors in charging piles is due to two main reasons: firstly, some users prioritize use over maintenance of switching devices, failing to recognize contactors as electrical components with a limited lifespan requiring maintenance; secondly, there is a lack of direct and convenient methods for testing DC contactor performance and predicting their lifespan. For the health status assessment technology of DC contactors in charging facilities, the core issue is studying their electrical lifespan. Therefore, it is essential to establish an experimental platform for testing the electrical lifespan of DC contactors, measuring their performance parameters, and conducting health prediction research.

[0059] The failure mechanism of DC contactors is usually due to the erosion effect of DC arc on the contacts of DC contactors. The state parameters selected in related technologies to characterize the cumulative damage of DC contactors are mostly cumulative arc energy, release time, release voltage, etc. These parameters can only be collected under specific equipment or high sampling frequency, making them difficult to apply in the field and difficult to achieve online detection.

[0060] Based on the above optional embodiments, a method for assessing the cumulative damage of DC charging pile output contactors based on break voltage and breaking current is provided, which solves the problems of unsatisfactory accuracy of current DC charging pile output contactor health assessment results and difficulty in reproducing the assessment.

[0061] Figure 4 This is a second schematic diagram of an optional method for determining the health of a DC contactor according to an embodiment of this application, as shown below. Figure 4 The diagram shows the process flow for determining the health status of the DC contactor in a charging pile. Figure 4As shown, firstly, the signal acquisition unit collects the break-point voltage data and segmented current data of the DC contactor as input feature quantities. Using the DC contactor health assessment model, the health level of the DC contactor is determined based on the collected break-point voltage and segmented current data. Based on this health level, maintenance strategies are determined for the DC contactor, such as replacing the DC contactor of the charging equipment when the health level is below 60%, and maintaining close monitoring of the break-point voltage and segmented current. The above-mentioned DC contactor health determination process includes two parts: determining the electrical life of the DC contactor and determining its health level.

[0062] To determine the electrical life of a DC contactor, firstly, the DC contactor (i.e., the output contactor of the charging pile) is subjected to breaking tests under rated voltage and current conditions (i.e., rated break voltage and rated breaking current) until the end of its electrical life, obtaining the distribution characteristics of single-pass contact erosion. Then, the output contactor is subjected to breaking tests under different break voltages and breaking currents until the end of its electrical life, resulting in a bivariate function model of the output contactor's electrical life versus break voltage U and breaking current I (i.e., dual characteristics). This bivariate function model is then used to determine the electrical life of the output contactor under different break voltages U and breaking currents I (i.e., dual characteristics).

[0063] To assess the health of a DC contactor, the target cumulative damage over its lifespan is obtained by accumulating single-instance damages obtained from a bivariate function model and correcting them using the environmental impact coefficient of single-instance losses. Based on this target cumulative damage, and combined with changes in performance parameters (i.e., vibration entropy and contact resistance), the health of the output contactor is calculated.

[0064] Figure 5 This is a third schematic diagram of an optional method for determining the health of a DC contactor according to an embodiment of this application, as shown below. Figure 5 This paper illustrates the process of determining the health status of DC contactors in charging piles. Based on the contactor's break voltage data, segmented current data, and the number of breaks (electrical life), a cumulative damage model (i.e., a bivariate function model) is determined. Using this model, the target cumulative damage (i.e., lifetime cumulative damage) is determined. Combined with changes in performance parameters (i.e., vibration entropy and contact resistance), a health status assessment model (i.e., a health state model) is used to obtain the contactor's health status. Based on this health status, guidance is provided for operation and maintenance, fault detection, and the operation and maintenance strategy is determined. When the lifetime cumulative damage value reaches 90%, the vibration entropy increases, and the contact resistance exceeds 1.5 times the steady-state period, the contactor is considered close to failure and needs replacement.

[0065] Adopting such Figure 2 The experimental platform shown performs breaking tests on a DC contactor. Figure 2The experimental platform shown includes a power source, a load, a protection unit, and a control unit. The power source simulates the charging equipment providing the rated break voltage and rated segmented current to the DC contactor during normal operation. The load simulates the actual power demand during charging. The protection unit protects the experimental platform and operators during testing. The control unit coordinates the operation of the experimental platform, including controlling the power source output, detecting electrical parameters (such as voltage, current, and arc energy) during the experiment, and recording experimental data.

[0066] like Figure 3 As shown, firstly, the output contactor is subjected to breaking tests under rated voltage and current (i.e., rated break voltage and rated breaking current) until the end of its electrical life, obtaining the distribution characteristics of single-time contact erosion. Then, the output contactor is subjected to breaking tests under different break voltages and breaking currents until the end of its electrical life, obtaining a bivariate function model of the output contactor's electrical life with respect to break voltage U and breaking current I. Based on the single-time erosion, break voltage U, and breaking current I, the single-time damage 1 / L (dimension 1 / time) of the DC contactor under this break voltage and breaking current is obtained using the bivariate function model. Finally, the break voltage and breaking current at each break of the output contactor are recorded, the single-time damage is calculated, the single-time damage is accumulated, and corrected using the single-time loss environmental influence coefficient, thus obtaining the target cumulative damage L of the output contactor over its life cycle. dmg L dmg It is obtained in the following way:

[0067]

[0068] Among them, L dmg For the target cumulative damage over the life cycle of the output contactor, L i Let γ represent the single-instance damage under the i-th group of port voltage and breaking current, n be the number of groups of port voltage and breaking current, and γ be the environmental impact coefficient of single-instance loss.

[0069] A health assessment model based on cumulative damage is established. The single-instance loss (1 / L) is calculated by online acquisition of the break voltage and breaking current, and the cumulative total damage is obtained by continuously accumulating single-instance damage. Combining historical life data of the output contactor, a cumulative damage model (i.e., a bivariate function model) is established using thin-plate spline interpolation fitting. Single-instance damage is determined by the single-instance erosion of the DC contactor, as well as the break voltage and breaking current on both sides at the breaking point. The health of the output contactor is obtained by accumulating single-instance damage and combining it with changes in performance parameters (i.e., vibration entropy and contact resistance). When the cumulative damage value reaches 90%, the vibration entropy increases, and the contact resistance exceeds 1.5 times the steady-state period, the contactor is considered close to failure and needs replacement.

[0070] The correlation between vibration entropy, contact resistance, cumulative damage and health of DC contactors is determined using a health assessment model. An example of the correlation can be shown in Table 1 above.

[0071] The above optional implementation methods achieve at least the following effects: by combining historical life data of DC contactors to determine the health status of DC contactors, the rationality and accuracy of the determination of cumulative damage of DC contactors can be improved, and the accuracy of the health status assessment results can be improved; by using the single-loss environmental impact coefficient to correct the initial cumulative damage of DC contactors to obtain the target cumulative damage, the influence of environmental factors on the health status of DC contactors is fully considered, further improving the accuracy and reliability of the health status assessment results of DC contactors of charging piles, and providing a more scientific basis for the maintenance, design and resource optimization of charging facilities.

[0072] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0073] This embodiment also provides a device for determining the health of a DC contactor, which is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the terms "module" and "device" can refer to a combination of software and / or hardware that performs a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0074] According to an embodiment of this application, an apparatus embodiment for implementing a method for determining the health status of a DC contactor is also provided. Figure 6 This is a schematic diagram of a DC contactor health determination device according to an embodiment of this application, as shown below. Figure 6 As shown, the above-mentioned DC contactor health determination device includes a data acquisition module 602, an initial cumulative damage determination module 604, a target cumulative damage determination module 606, and a health determination module 608. The device will be described below.

[0075] Data acquisition module 602 is used to acquire historical lifespan data of DC contactors;

[0076] The initial cumulative damage determination module 604 is connected to the data acquisition module 602 and is used to determine the initial cumulative damage of the DC contactor based on historical life data.

[0077] The target cumulative damage determination module 606 is connected to the initial cumulative damage determination module 604. It is used to correct the initial cumulative damage based on the single loss environmental impact coefficient to obtain the target cumulative damage of the DC contactor. The single loss environmental impact coefficient is used to reflect the degree of damage to the DC contactor caused by environmental factors when the DC contactor performs closing or opening operations.

[0078] The health determination module 608 is connected to the target cumulative damage determination module 606 and is used to determine the health of the DC contactor based on the target cumulative damage.

[0079] This application provides a device for determining the health of a DC contactor. A data acquisition module 602 is used to acquire historical lifespan data of the DC contactor. An initial cumulative damage determination module 604, connected to the data acquisition module 602, is used to determine the initial cumulative damage of the DC contactor based on the historical lifespan data. A target cumulative damage determination module 606, connected to the initial cumulative damage determination module 604, is used to correct the initial cumulative damage based on a single-loss environmental impact coefficient to obtain the target cumulative damage of the DC contactor. The single-loss environmental impact coefficient reflects the degree of wear and tear on the DC contactor caused by environmental factors during closing or opening operations. A health determination module 608, connected to the target cumulative damage determination module 606, is used to determine the health of the DC contactor based on the target cumulative damage. This achieves the goal of determining the initial cumulative damage of the DC contactor based on its historical lifespan data and correcting the initial cumulative damage using the single-loss environmental impact coefficient to obtain the target cumulative damage. This improves the accuracy of the health determination results for the DC contactor and solves the technical problem of low accuracy in determining the health of DC contactors in related technologies.

[0080] It should be noted that the above modules can be implemented by software or hardware. For example, for the latter, it can be implemented in the following ways: the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0081] It should be noted that the data acquisition module 602, the initial cumulative damage determination module 604, the target cumulative damage determination module 606, and the health determination module 608 mentioned above correspond to steps S102 to S108 in the embodiments. The instances and application scenarios implemented by the above modules and corresponding steps are the same, but are not limited to the content disclosed in the above embodiments. It should be noted that the above modules, as part of the device, can run in a computer terminal.

[0082] It should be noted that the optional or preferred implementation methods of this embodiment can be found in the relevant descriptions in the embodiments, and will not be repeated here.

[0083] The aforementioned DC contactor health determination device may further include a processor and a memory. The data acquisition module 602, the initial cumulative damage determination module 604, the target cumulative damage determination module 606, and the health determination module 608 are all stored as program units in the memory, and the processor executes the aforementioned program units stored in the memory to realize the corresponding functions.

[0084] The processor contains a core that retrieves the corresponding program unit from memory. One or more cores may be configured. Memory may include non-persistent memory in computer-readable media, random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory includes at least one memory chip.

[0085] This application provides a non-volatile storage medium storing a program that, when executed by a processor, implements a method for determining the health status of a DC contactor.

[0086] This application provides an electronic device including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs the following steps: acquiring historical lifespan data of a DC contactor; determining the initial cumulative damage of the DC contactor based on the historical lifespan data; correcting the initial cumulative damage based on a single-loss environmental impact coefficient to obtain the target cumulative damage of the DC contactor, wherein the single-loss environmental impact coefficient reflects the degree of wear and tear on the DC contactor during closing or opening operations; and determining the health status of the DC contactor based on the target cumulative damage. The device described herein may be a server, PC, etc.

[0087] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having the following method steps: acquiring historical life data of a DC contactor; determining the initial cumulative damage of the DC contactor based on the historical life data; correcting the initial cumulative damage based on a single-loss environmental impact coefficient to obtain the target cumulative damage of the DC contactor, wherein the single-loss environmental impact coefficient is used to reflect the degree of wear and tear on the DC contactor by environmental factors when the DC contactor performs closing or opening operations; and determining the health status of the DC contactor based on the target cumulative damage.

[0088] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0089] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0090] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0091] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0092] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0093] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0094] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0095] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0096] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0097] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for determining the health status of a DC contactor, characterized in that, include: Obtain historical lifespan data for DC contactors; Based on the historical lifespan data, the initial cumulative damage of the DC contactor is determined; Based on the single-loss environmental impact coefficient, the initial cumulative damage is corrected to obtain the target cumulative damage of the DC contactor. The single-loss environmental impact coefficient is used to reflect the degree of damage to the DC contactor caused by environmental factors when the DC contactor performs a closing or opening operation. The health status of the DC contactor is determined based on the target cumulative damage.

2. The method according to claim 1, characterized in that, The determination of the initial cumulative damage of the DC contactor based on the historical lifespan data includes: The historical life data includes multiple sets of historical operating data of the DC contactor, and multiple single damages corresponding to the multiple sets of historical operating data. Each set of historical operating data includes historical break voltage data and historical segmented current data. The multiple sets of historical operating data correspond one-to-one with the multiple single damages. The initial cumulative damage is obtained by accumulating the multiple single damages.

3. The method according to claim 2, characterized in that, The determination of the multiple sets of historical operating data of the DC contactor included in the historical life data, and the multiple single damages corresponding to the multiple sets of historical operating data, includes: The electrical life data of the DC contactor, the historical break voltage data, and the segmented current data included in the historical life data are fitted to obtain a bivariate function model of the DC contactor. The bivariate function model is used to reflect the bivariate function relationship between the electrical life of the DC contactor and the break voltage and segmented current. Determine the single erosion amount of the contacts of the DC contactor, wherein the single erosion amount represents the degree to which the contact material is removed or damaged during each closing or opening operation of the contacts of the DC contactor; Based on the historical break voltage data, the historical segmented current data, and the single erosion amount, the single damage to the DC contactor is determined using the binary function model.

4. The method according to claim 3, characterized in that, Determining the amount of erosion of the contacts of the DC contactor in a single instance includes: Under the conditions of rated break voltage and rated segmented current, the DC contactor is subjected to a breaking test to determine the distribution characteristics of the single erosion amount of the contact of the DC contactor. The amount of erosion per incident is determined based on the distribution characteristics.

5. The method according to claim 4, characterized in that, The breaking test of the DC contactor under rated breaking voltage and rated segmented current conditions includes: An experimental platform is constructed, comprising a power source, a load, a protection unit, and a control unit. Under the conditions of the rated break voltage and the rated segmented current, the DC contactor is subjected to the breaking test based on the experimental platform.

6. The method according to claim 1, characterized in that, Determining the health status of the DC contactor based on the target cumulative damage includes: Determine the vibration entropy and contact resistance of the DC contactor, wherein the vibration entropy represents the degree of disorder of the vibration modes of the mechanical components inside the DC contactor, and the contact resistance refers to the resistance between the two contact surfaces of the DC contactor; Based on the vibration entropy, the contact resistance, and the target cumulative damage, a health assessment model is used to obtain the health status, wherein the health assessment model has pre-learned the correspondence between the vibration entropy, the contact resistance, the cumulative damage, and the health status of the DC contactor.

7. The method according to any one of claims 1 to 6, characterized in that, Before correcting the initial cumulative damage based on the single-loss environmental impact coefficient to obtain the target cumulative damage of the DC contactor, the method further includes: The various environmental parameters included in the historical lifespan data are normalized to obtain the standard environmental parameters corresponding to each of the various environmental parameters. Determine the weighting coefficients corresponding to the various environmental parameters; The environmental impact coefficient of a single loss is determined based on the weighting coefficients corresponding to the various environmental parameters and the standard environmental parameters corresponding to the various environmental parameters.

8. A device for determining the health status of a DC contactor, characterized in that, include: The data acquisition module is used to acquire historical lifespan data of the DC contactor; An initial cumulative damage determination module is used to determine the initial cumulative damage of the DC contactor based on the historical life data. The target cumulative damage determination module is used to correct the initial cumulative damage based on the single-loss environmental impact coefficient to obtain the target cumulative damage of the DC contactor. The single-loss environmental impact coefficient is used to reflect the degree of damage to the DC contactor caused by environmental factors when the DC contactor performs a closing or opening operation. A health determination module is used to determine the health of the DC contactor based on the target cumulative damage.

9. A non-volatile storage medium, characterized in that, The non-volatile storage medium stores multiple instructions adapted for loading by a processor and executing the method for determining the health of a DC contactor as described in any one of claims 1 to 7.

10. An electronic device, characterized in that, include: One or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method for determining the health of a DC contactor as described in any one of claims 1 to 7.

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