Vehicle state detection method, medium and vehicle

Abstract

This application discloses a vehicle condition detection method, medium, and vehicle, relating to the field of fault detection technology. The method includes: acquiring current and voltage data at the grounding point of the grounding circuit when a current step occurs in the grounding circuit; determining the transient equivalent resistance of the grounding point over at least two time windows based on the current and voltage data; wherein the transient equivalent resistance is the ratio of voltage change to current change, which can be decomposed into a contact resistance component and a parasitic inductance voltage component at the grounding point; calculating the transient equivalent resistance over at least two time windows to cancel out the parasitic inductance voltage component, thus obtaining the contact resistance component of the grounding point; and determining the contact state of the grounding point of the grounding circuit based on the contact resistance component. The technical solution of this application can detect early contact degradation problems in a timely manner, reducing the risk of missed detections.

Description

Technical Field

[0001] This application relates to the field of vehicle fault detection technology, specifically to a vehicle condition detection method, medium, and vehicle. Background Technology

[0002] In the high-voltage electrical system of new energy vehicles, in order to ensure the electrical safety and reliable operation of the vehicle, it is usually necessary to test the contact status of the grounding circuit in order to detect poor contact problems caused by loose bolts, oxidation and corrosion, etc.

[0003] In related technologies, the static voltage difference method is often used to evaluate the contact status of grounding circuits. This method collects the grounding point voltage under steady-state system conditions and judges the contact status according to a fixed threshold. However, in high-current circuits, the millivolt-level resistive voltage drop characterizing early contact degradation is easily overwhelmed by system noise, resulting in insufficient detection sensitivity, inaccurate judgment of contact status, and a high risk of missed detections. Summary of the Invention

[0004] In view of this, the embodiments of this application aim to provide a vehicle condition detection method, medium and vehicle, so as to improve the sensitivity and accuracy of grounding point condition detection and detect early contact deterioration problems in a timely manner.

[0005] In a first aspect, one embodiment of this application provides a vehicle state detection method, comprising: acquiring current data and voltage data at the grounding point of the grounding circuit when a current step occurs in the grounding circuit; determining the transient equivalent resistance of the grounding point in at least two time windows based on the current data and voltage data; wherein the transient equivalent resistance is the ratio of voltage change to current change, which can be decomposed into a contact resistance component and a parasitic inductance voltage component of the grounding point; canceling the parasitic inductance voltage component by numerically calculating the transient equivalent resistance in at least two time windows to obtain the contact resistance component of the grounding point; and determining the contact state of the grounding point of the grounding circuit based on the contact resistance component of the grounding point.

[0006] This application embodiment collects current and voltage data when the grounding circuit is in a current step state. Compared with the steady-state condition, the current change rate is larger under current step conditions. The larger current change amplifies the signal generated by the contact resistance, making the voltage change characterizing the contact resistance more prominent and effectively preventing early degradation signals from being drowned out by system noise. At the same time, by numerically calculating the transient equivalent resistance of at least two time windows, the interference of voltage components generated by parasitic inductance is canceled, and the contact resistance component that can accurately reflect the contact state of the grounding point is obtained, thereby accurately judging the contact state of the grounding point. Therefore, this application embodiment improves the sensitivity and accuracy of grounding point state detection, can detect early contact degradation problems in a timely manner, reduce the risk of missed detection, and effectively ensure the reliability and safety of the grounding circuit operation.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, at least two time windows include a rising edge time window and a falling edge time window in the same step event; by numerically calculating the transient equivalent resistance of at least two time windows, the parasitic inductance voltage component is canceled to obtain the contact resistance component of the grounding point, including: calculating the transient equivalent resistance of the rising edge time window and the arithmetic mean of the transient equivalent resistance of the falling edge time window to cancel the parasitic inductance voltage component and obtain the contact resistance component of the grounding point.

[0008] This embodiment of the application sets the time window for numerical calculation to the rising edge time window and the falling edge time window in the same step event. It utilizes the physical law that the parasitic inductance voltage components are in opposite directions while the contact resistance voltage components are in the same direction to calculate the arithmetic mean of the two transient equivalent resistances. This allows for the reliable cancellation of parasitic inductance voltage components with the simplest mathematical calculation, ensuring the accuracy and stability of the detection results. Furthermore, the calculation can be completed with a single current step event, eliminating the need to wait for multiple operating conditions. This avoids contact resistance drift caused by excessively long intervals, further improving the reliability and efficiency of the detection results.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, there are multiple grounding points; the contact state of the grounding points in the grounding circuit is determined based on the contact resistance components of the grounding points, including: for any grounding point, if the contact resistance component of the grounding point exceeds the target resistance component, the contact resistance component of the grounding point is numerically compared with the contact resistance components of the remaining grounding points, and the contact state of the grounding point is determined based on the comparison result.

[0010] In the case of multiple grounding points, when the contact resistance component of any grounding point exceeds the standard, its value is compared with the contact resistance components of the remaining grounding points. This can effectively distinguish whether the fault is caused by the deterioration of a single grounding point or by an abnormality in the entire grounding circuit, thus avoiding misjudgment and improving the accuracy of grounding point fault location.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: determining the target resistance component based on the cross-sectional area of ​​the conductor in the grounding circuit; wherein the cross-sectional area is negatively correlated with the target resistance component.

[0012] This application embodiment establishes a negative correlation between the target resistance component and the cross-sectional area of ​​the conductor, so that the determined target resistance component matches the physical specifications of the conductor. This ensures that the target resistance component is suitable for the detection requirements of the grounding point of the current grounding circuit, avoids misjudgment or missed detection due to the use of a fixed threshold, and further improves the accuracy of grounding point status determination.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the contact state of the grounding point is determined based on the comparison results, including: determining the maximum component from the contact resistance components of each remaining grounding point; if the contact resistance component of the grounding point exceeds the maximum component of the target multiple, and the difference between the contact resistance components of each remaining grounding point is less than the target difference, then the contact state is determined to be a fault state; wherein, the target multiple is greater than 1.

[0014] This application embodiment compares the contact resistance component of the grounding point to be detected with the maximum component, and judges the fault by combining the difference in contact resistance components of the remaining grounding points. When multiple grounding points coexist, it can accurately locate the grounding point that has deteriorated, avoid misjudging the overall circuit fault, and also eliminate the interference of the overall circuit abnormality on the judgment of single-point faults. It effectively improves the accuracy of fault location in multi-point grounding circuits, facilitates maintenance personnel to quickly troubleshoot and locate problems, and reduces the time cost of maintenance.

[0015] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: in response to the operating condition command of the vehicle controller, acquiring the current signal of the grounding circuit; determining the rate of change of the current signal; and determining that a current step has occurred in the grounding circuit when the rate of change of the current exceeds a target threshold.

[0016] This application embodiment predicts upcoming current changes by using the operating condition commands of the vehicle controller and initiates the data acquisition process in advance. This avoids missing current step events and eliminates the need for real-time monitoring of current changes in the circuit, reducing unnecessary invalid data acquisition and lowering system computing power consumption. At the same time, by filtering valid current step events through a current change rate threshold, it can eliminate small current fluctuations and random noise interference, avoid false triggering of detection, and further improve the stability and reliability of the detection process.

[0017] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: determining the execution time of the operating condition command and the abrupt change time of the current signal; determining the time difference between the execution time and the abrupt change time; determining that a current step occurs in the grounding circuit when the current change rate exceeds a target threshold, including: determining that a current step occurs in the grounding circuit when the current change rate exceeds the target threshold and the time difference is less than the target time difference.

[0018] This application combines the time difference between the execution time and the sudden change time with the current change rate to verify whether the current change is a real current step caused by the execution of the operating condition command, thereby eliminating interference such as random noise and false touch signals, effectively improving the accuracy of current step judgment, avoiding invalid detection, and ensuring the reliability of the entire detection process.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, before determining the transient equivalent resistance of the grounding point over at least two time windows based on the current data and voltage data, the method further includes: determining, based on the current data, whether there is an abnormal current jump exceeding the target jump threshold between consecutive sampling points within the time window; if there is an abnormal current jump, or the voltage data exceeds the target voltage range, then in the event of a current step in the grounding circuit, the current data and voltage data at the grounding point are re-acquired.

[0020] This application embodiment verifies the validity of current and voltage data collected within a time window, promptly identifies data with interference or abnormal collection, and ensures the quality of data used in subsequent calculations by triggering a re-sampling mechanism. This avoids the impact of low-quality data on the calculation results and improves the reliability and accuracy of the contact resistance component calculation results.

[0021] Secondly, this application provides a vehicle state detection device, comprising: a data acquisition module for acquiring current and voltage data at the grounding point of the grounding circuit when a current step occurs in the grounding circuit; a resistance determination module for determining the transient equivalent resistance of the grounding point in at least two time windows based on the current and voltage data; wherein the transient equivalent resistance is the ratio of voltage change to current change, which can be decomposed into a contact resistance component and a parasitic inductance voltage component of the grounding point; a numerical calculation module for canceling the parasitic inductance voltage component by numerically calculating the transient equivalent resistance in at least two time windows to obtain the contact resistance component of the grounding point; and a state determination module for determining the contact state of the grounding point of the grounding circuit based on the contact resistance component of the grounding point.

[0022] Thirdly, one embodiment of this application provides a computer-readable storage medium storing a computer program for performing the method in the first aspect or any possible implementation of the first aspect.

[0023] Fourthly, one embodiment of this application provides a vehicle, the vehicle comprising: a processor; a memory for storing processor-executable instructions; the processor being configured to execute the method in the first aspect or any possible implementation thereof.

[0024] Fifthly, one embodiment of this application provides a computer program product including instructions that, when executed on a vehicle, cause the vehicle to implement the method in the first aspect or any possible implementation of the first aspect.

[0025] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The diagram shown is a schematic flowchart of a vehicle state detection method provided in an embodiment of this application.

[0028] Figure 2 The diagram shown is a structural schematic of a vehicle condition detection device provided in an embodiment of this application.

[0029] Figure 3 The diagram shown is a structural schematic of a vehicle provided in an embodiment of this application. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0031] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0032] It should be understood that the term "and / or" used in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. Additionally, the term "based on" used in this document is not limited to relying solely on one object. For example, determining B based on A can mean: determining B based solely on A, or determining B partially based on A.

[0033] In the field of online monitoring of grounding circuits, the common practice in related technologies to assess the contact status of grounding points is to collect and analyze the electrical parameters of the grounding circuit. Specifically, the grounding point voltage under steady-state conditions is monitored and compared with a preset fixed threshold to determine whether poor contact has occurred. However, for early contact degradation, the increase in grounding point contact resistance is usually small, and the resulting voltage change is also at the millivolt level. In high-current circuits, this weak voltage change is easily masked by the system's own noise, leading to inaccurate judgments. For example, when the system noise amplitude is 20 millivolts, the early degradation signal with an amplitude of only about 5 millivolts will be submerged by the noise, resulting in insufficient detection sensitivity and inability to accurately identify early contact degradation problems. Moreover, it is also susceptible to electromagnetic compatibility interference and the influence of ambient temperature.

[0034] Furthermore, simply adjusting the measurement to acquire the grounding point voltage under transient conditions and comparing it with a fixed threshold, based on relevant technologies, still cannot solve the above problem. This is because parasitic inductance exists in the grounding circuit itself. When the current changes, the parasitic inductance generates an induced electromotive force (EMF). This induced EMF is superimposed on the voltage drop generated by the contact resistance, causing the measured voltage to fail to accurately reflect the voltage drop across the contact resistance, thus affecting the accuracy of the contact status assessment.

[0035] To address the aforementioned issues, this application utilizes the characteristic of a large rate of change of current during a current step to amplify the voltage signal of the contact resistance. Simultaneously, it uses numerical calculations at different time windows to cancel the induced voltage interference of parasitic inductance, ultimately obtaining a contact resistance component that accurately reflects the contact state of the grounding point. This solves the problems in related technologies where early degradation signals are easily submerged by noise and parasitic inductance interferes with detection results, thereby improving the sensitivity and accuracy of early degradation detection.

[0036] The following is combined with Figure 1 The vehicle status detection method provided in the embodiments of this application will be described in detail.

[0037] Figure 1 The diagram shown is a schematic flowchart of a vehicle state detection method provided in an embodiment of this application; as follows: Figure 1 As shown, the method includes the following steps.

[0038] Step S110: When a current step occurs in the grounding circuit, collect the current and voltage data at the grounding point of the grounding circuit.

[0039] In this context, "grounding circuit" refers to the current path formed by connecting high-voltage electrical components in a new energy vehicle's high-voltage system to the vehicle's ground. "Ground point" refers to the connection point in the grounding circuit that electrically connects the reference potential point of the high-voltage electrical component to the vehicle chassis to achieve the current loop. Examples of ground points include the battery negative terminal ground point, the motor housing ground point, and the fast charging port ground point. "Current step" refers to an event where the current in the grounding circuit changes rapidly and significantly. For example, a current step can be a transient change in current that occurs during processes such as drive start-up, energy recovery, and fast charging switching triggered by vehicle controller commands.

[0040] In some embodiments, there are multiple ways to determine whether a current step has occurred in the grounding circuit. For example, the drive signal of the power switch in the grounding circuit can be acquired, and a current step is determined to have occurred when the drive signal switches from an off state to an on state or from an on state to an off state; or, the bus voltage of the grounding circuit can be monitored, and a current step is determined to have occurred when the bus voltage experiences a transient fluctuation with an amplitude exceeding a preset threshold and a duration less than a preset duration.

[0041] In practice, current data at the grounding point can be directly reused from the vehicle's existing Hall current sensor. Voltage data can be collected by reusing the ground voltage analog-to-digital converter (ADC) channel of the microcontroller unit to acquire the voltage at the grounding point relative to the reference ground. Using this method, the entire process requires no additional sensors or excitation circuits, achieving non-invasive diagnostics.

[0042] Furthermore, after a current step, at least two time windows can be locked for current and voltage data acquisition. For example, the duration of the time window can be 5 to 10 milliseconds, and discrete data points of current and voltage within the time window can be acquired synchronously at a sampling frequency of 20 kHz.

[0043] Step S120: Based on the current data and voltage data, determine the transient equivalent resistance of the grounding point in at least two time windows; wherein, the transient equivalent resistance is the ratio of the voltage change to the current change, which can be decomposed into the contact resistance component and the parasitic inductance voltage component of the grounding point.

[0044] The transient equivalent resistance is the ratio of the voltage change to the corresponding current change at the grounding point within the time window. It can be characterized as the superposition of the contact resistance component and the parasitic inductance voltage component. The contact resistance component refers to the pure resistance portion related to the contact interface at the grounding point, and its value reflects the physical state of the grounding contact. This component is independent of the current direction and always exhibits a positive resistance. The parasitic inductance voltage component refers to the induced voltage generated by the parasitic inductance of the wiring harness when the current changes. The polarity of this component changes with the direction of the current change.

[0045] In practice, the current change within each time window is determined based on current data. Similarly, the voltage change within each time window is determined based on voltage data. For each time window, the ratio of the voltage change to the current change is calculated to obtain the instantaneous equivalent resistance. This instantaneous equivalent resistance includes both the contact resistance component at the grounding point and the parasitic inductance voltage component caused by the current change. For example, if the current changes by 100 amperes and the voltage changes by 50 millivolts within a time window, the instantaneous equivalent resistance for that time window is 0.5 milliohms. This 0.5 milliohm is not the actual contact resistance, but rather the superposition of the contact resistance and the equivalent resistance of the inductance voltage.

[0046] Step S130: By numerically calculating the transient equivalent resistance of at least two time windows, the parasitic inductance voltage component is canceled out, and the contact resistance component of the grounding point is obtained.

[0047] It should be noted that the polarity of the parasitic inductance voltage component depends on the sign of the rate of change of current; and the sign of the rate of change of current may differ in different time windows, causing the parasitic inductance voltage component to exhibit opposite polarities. The contact resistance component, however, is determined by the resistance itself, and its voltage change to current change ratio is always positive and its polarity remains constant. Based on these physical characteristics, the parasitic inductance voltage component can be canceled out and the contact resistance component extracted by numerically calculating the transient equivalent resistance of the two time windows.

[0048] Specifically, since the transient equivalent resistance has a linear relationship with the characteristic parameter (i.e., the ratio of the rate of change of current to the amount of change of current), the parasitic inductance voltage component in the transient equivalent resistance is proportional to the characteristic parameter, while the contact resistance component exists independently as a constant. Therefore, the transient equivalent resistance and its corresponding characteristic parameter for each time window can be calculated. By using the linear relationship between the transient equivalent resistance and the characteristic parameter to solve simultaneously or perform linear fitting, the parasitic inductance voltage component can be canceled, thus obtaining the contact resistance component.

[0049] It should be noted that the at least two time windows can be windows for different current step events, or they can belong to the same current step event. For example, a time window can be selected from two different drive start events, or different time windows can be selected from the same drive start event. Both methods can use numerical calculations to cancel the parasitic inductance voltage component and obtain the contact resistance component.

[0050] Step S140: Determine the contact state of the grounding point of the grounding circuit based on the contact resistance component of the grounding point.

[0051] The contact status reflects the degree of deterioration of the physical contact at the grounding point. For example, the contact status can include normal, slightly deteriorated, and severely faulty.

[0052] In this embodiment, the magnitude of the contact resistance component is related to the physical contact state of the grounding point. When the contact state is good, the contact resistance component is usually stable at an extremely low value (e.g., in the micro-ohm or milliohm range); if early deterioration occurs at the grounding point, such as loose bolts, oxidation or corrosion of the contact surface, the contact resistance component will increase. Therefore, the contact resistance component can be compared with a preset threshold to determine the contact state of the grounding point.

[0053] Specifically, if the contact resistance component is less than the first preset threshold, the grounding point is considered to be in normal contact condition; if the contact resistance component is greater than or equal to the first preset threshold and less than the second preset threshold, the grounding point is considered to be in slightly deteriorated contact condition, which can trigger the vehicle instrument panel to prompt the user to check during subsequent maintenance; if the contact resistance component is greater than or equal to the second preset threshold, the grounding point is considered to be in serious fault condition, which triggers the vehicle alarm to prompt the user to repair immediately to avoid safety hazards such as overheating and burning.

[0054] This application embodiment collects current and voltage data when the grounding circuit is in a current step state. Compared with the steady-state condition, the current change rate is larger under current step conditions. The larger current change amplifies the signal generated by the contact resistance, making the voltage change characterizing the contact resistance more prominent and effectively preventing early degradation signals from being drowned out by system noise. At the same time, by numerically calculating the transient equivalent resistance of at least two time windows, the interference of voltage components generated by parasitic inductance is canceled, and the contact resistance component that can accurately reflect the contact state of the grounding point is obtained, thereby accurately judging the contact state of the grounding point. Therefore, this application embodiment improves the sensitivity and accuracy of grounding point state detection, can detect early contact degradation problems in a timely manner, reduce the risk of missed detection, and effectively ensure the reliability and safety of the grounding circuit operation.

[0055] To further illustrate the specific implementation of canceling parasitic inductance voltage components through numerical calculation, this application also provides a preferred embodiment. As mentioned above, the at least two time windows can be selected in various ways. In this embodiment, the at least two time windows include the rising edge time window and the falling edge time window within the same step event. Optionally, the parasitic inductance voltage components are canceled by numerically calculating the transient equivalent resistances of the at least two time windows to obtain the contact resistance component of the grounding point. This includes: calculating the arithmetic mean of the transient equivalent resistance of the rising edge time window and the transient equivalent resistance of the falling edge time window to cancel the parasitic inductance voltage components and obtain the contact resistance component of the grounding point.

[0056] In practical applications, within the same step event, the current first experiences a rising phase (rising edge) and then a falling phase (falling edge). During data acquisition, one data acquisition time window can be set at the rising edge, resulting in the rising edge time window; another data acquisition time window can be set at the falling edge of the same step event, resulting in the falling edge time window.

[0057] Specifically, based on the current and voltage data collected during the rising edge time window, the ratio of voltage change to current change is determined as the transient equivalent resistance for the rising edge time window. Similarly, based on the current and voltage data collected during the falling edge time window, the transient equivalent resistance for the falling edge time window is determined. For example, the formula for the transient equivalent resistance is as follows: in, ΔV This represents the voltage change within the time window. ΔI This represents the change in current within the time window. R1 For transient equivalent resistance, R2 For contact resistance components, L For the parasitic inductance of the ground circuit, γ It is the ratio of the rate of change of current to the amount of change of current within the time window, i.e., the characteristic parameter.

[0058] For the rising edge time window, the rate of change of current is greater than 0, so the corresponding parasitic inductance voltage component is positive; for the falling edge time window, the rate of change of current is less than 0, so the parasitic inductance voltage component is negative. The contact resistance component remains positive and has the same magnitude in both time windows. Therefore, by taking the arithmetic mean of the two transient equivalent resistances, the parasitic inductance voltage components with opposite signs cancel each other out, and the final average value is the contact resistance component.

[0059] This embodiment of the application sets the time window for numerical calculation to the rising edge time window and the falling edge time window in the same step event. It utilizes the physical law that the parasitic inductance voltage components are in opposite directions while the contact resistance voltage components are in the same direction to calculate the arithmetic mean of the two transient equivalent resistances. This allows for the reliable cancellation of parasitic inductance voltage components with the simplest mathematical calculation, ensuring the accuracy and stability of the detection results. Furthermore, the calculation can be completed with a single current step event, eliminating the need to wait for multiple operating conditions. This avoids contact resistance drift caused by excessively long intervals, further improving the reliability and efficiency of the detection results.

[0060] To further optimize the accuracy of fault location in the above embodiments, when there are multiple grounding points in the grounding circuit, such as the battery negative grounding point, motor housing grounding point, fast charging interface grounding point, and other critical locations in new energy vehicles, this application also provides a preferred scheme for multi-point topology positioning. Optionally, there are multiple grounding points; the contact state of the grounding points in the grounding circuit is determined based on the contact resistance components of the grounding points, including: for any grounding point, if the contact resistance component of the grounding point exceeds the target resistance component, then the contact resistance component of the grounding point is numerically compared with the contact resistance components of the remaining grounding points, and the contact state of the grounding point is determined based on the comparison result.

[0061] Specifically, after calculating a contact resistance component for each grounding point, the contact resistance component of each grounding point can be compared with the target resistance component. It should be noted that the target resistance component can be preset according to the structure of the grounding point, or it can be a normal reference value generated statistically based on historical detection data from multiple detection cycles of the vehicle.

[0062] Furthermore, for each grounding point, if the contact resistance component of that grounding point exceeds the target resistance component, it indicates that the grounding point may be deteriorating. To ensure the accuracy of the contact status, this contact resistance component can be compared with the contact resistance components of the remaining grounding points other than that grounding point, and the contact status can be determined based on the comparison result.

[0063] For example, the contact resistance component of the grounding point is compared with the maximum component among the contact resistance components of all remaining grounding points. If the contact resistance component of the grounding point is greater than the maximum component, the contact condition is determined to be a fault condition.

[0064] In the case of multiple grounding points, when the contact resistance component of any grounding point exceeds the standard, its value is compared with the contact resistance components of the remaining grounding points. This can effectively distinguish whether the fault is caused by the deterioration of a single grounding point or by an abnormality in the entire grounding circuit, thus avoiding misjudgment and improving the accuracy of grounding point fault location.

[0065] In some embodiments, determining the contact state of a grounding point based on the comparison results includes: determining the maximum component from the contact resistance components of each remaining grounding point; if the contact resistance component of a grounding point exceeds the maximum component of a target multiple, and the difference between the contact resistance components of each remaining grounding point is less than the target difference, then the contact state is determined to be a fault state.

[0066] The target multiple is greater than 1. For example, the target multiple is 1.5. The maximum component is the maximum value of the contact resistance component at each remaining tower point. The variability can be calculated by dividing the standard deviation of the contact resistance component at each remaining grounding point by its average value, reflecting the dispersion of the contact resistance component at each remaining grounding point. The target variability can be set according to the actual situation.

[0067] In practice, the maximum component can be determined from the contact resistance components of each remaining grounding point; and the maximum component of the target multiple is compared with the contact resistance components of the grounding point. If the contact resistance component of the grounding point is greater than the maximum component of the target multiple, and the difference between the contact resistance components of the remaining grounding points is less than the preset target difference, it indicates that only the contact resistance component of the currently detected grounding point is abnormally large, and the other grounding points are all in the normal range, without general deterioration. In this case, the grounding point can be directly identified as the fault point, and its contact condition can be determined as faulty.

[0068] Furthermore, if the contact resistance component of the grounding point is greater than the maximum component of the target multiple, but the other differences are greater than or equal to the target differences, it indicates that the contact resistance of multiple grounding points is discrete overall. This may be due to an abnormality in the entire grounding circuit (such as drift of the measurement reference point or general degradation of the grounding integrity of the system), rather than a single grounding point fault. In this case, the test can be repeated.

[0069] In addition, if the contact resistance component of the grounding point does not exceed the target resistance component, the contact status of the grounding point can be directly determined to be normal.

[0070] The maximum component is determined from the contact resistance components of each remaining grounding point; if the contact resistance component of a grounding point exceeds the maximum component of the target multiple, and the difference between the contact resistance components of each remaining grounding point is less than the target difference, then the contact condition is determined to be a fault condition.

[0071] This application embodiment compares the contact resistance component of the grounding point to be detected with the maximum component, and judges the fault by combining the difference in contact resistance components of the remaining grounding points. When multiple grounding points coexist, it can accurately locate the grounding point that has deteriorated, avoid misjudging the overall circuit fault, and also eliminate the interference of the overall circuit abnormality on the judgment of single-point faults. It effectively improves the accuracy of fault location in multi-point grounding circuits, facilitates maintenance personnel to quickly troubleshoot and locate problems, and reduces the time cost of maintenance.

[0072] Given the varying sensitivities of high-voltage line harnesses to contact resistance across different specifications, a target resistance component can be set based on the specific application to improve the accuracy and versatility of condition assessment. Optionally, the method further includes determining the target resistance component based on the cross-sectional area of ​​the conductor in the grounding circuit; wherein the cross-sectional area is negatively correlated with the target resistance component.

[0073] The conductor is the high-voltage wiring harness connecting the high-voltage electrical components to the grounding point. A larger cross-sectional area of ​​the harness allows for a larger rated current, lower internal resistance, and a lower overall circuit impedance. Therefore, with the same increase in contact resistance, the increase in contact resistance at the grounding point of a larger cross-sectional area conductor accounts for a larger proportion of the total circuit impedance, and its impact on system performance is more significant. To ensure judgment sensitivity, the target resistance component setting needs to be correspondingly reduced for conductors with larger cross-sectional areas.

[0074] In practice, a table mapping the cross-sectional area of ​​different conductors to the target resistance component can be pre-established. During testing, the target resistance component can be directly obtained from the table based on the cross-sectional area of ​​the conductor corresponding to the current grounding point. For example, for wire harnesses with a cross-sectional area of ​​20 to 25 square millimeters, the target resistance component can be set to 0.4 millivolts per ampere; while for wire harnesses with a cross-sectional area of ​​35 to 50 square millimeters, the target resistance component should be set to 0.25 millivolts per ampere.

[0075] This application embodiment establishes a negative correlation between the target resistance component and the cross-sectional area of ​​the conductor, so that the determined target resistance component matches the physical specifications of the conductor. This ensures that the target resistance component is suitable for the detection requirements of the grounding point of the current grounding circuit, avoids misjudgment or missed detection due to the use of a fixed threshold, and further improves the accuracy of grounding point status determination.

[0076] To further avoid the problem of being falsely triggered by non-realistic step events (such as noise interference), this application also provides a detection method. Specifically, the method further includes: in response to the operating condition command of the vehicle controller, acquiring the current signal of the grounding circuit; determining the rate of change of the current signal; and determining that a current step has occurred in the grounding circuit when the rate of change of the current exceeds a target threshold.

[0077] Specifically, the vehicle controller continuously issues various operating condition commands, such as torque output commands, gear shifting commands, and charging control commands. The execution of these commands usually directly leads to a significant change in the high-voltage circuit current. Therefore, an impending current step can be predicted based on the operating condition commands, triggering the acquisition of the current signal in the grounding circuit.

[0078] Furthermore, when the rate of change of current exceeds a preset target threshold (e.g., 150 amperes per millisecond), it indicates that the current change is significant and a current step has occurred in the grounding circuit. If the rate of change of current does not exceed the target threshold, it indicates that the current change is small and may be a normal small current fluctuation rather than a valid current step event that can be detected.

[0079] For example, in response to a sudden torque output command from the vehicle controller, the current signal acquisition of the grounding circuit is triggered. If the current change rate of the current signal is determined to be 200 amps per millisecond, which exceeds 150 amps per millisecond, it can be determined that there is a valid current step, and the subsequent contact resistance component calculation steps can be executed. If the detected current change rate is only 80 amps per millisecond, which does not exceed 150 amps per millisecond, it is determined that no valid current step has been generated, the data acquired this time is discarded, and the data is acquired again.

[0080] This application embodiment predicts upcoming current changes by using the operating condition commands of the vehicle controller and initiates the data acquisition process in advance. This avoids missing current step events and eliminates the need for real-time monitoring of current changes in the circuit, reducing unnecessary invalid data acquisition and lowering system computing power consumption. At the same time, by filtering valid current step events through a current change rate threshold, it can eliminate small current fluctuations and random noise interference, avoid false triggering of detection, and further improve the stability and reliability of the detection process.

[0081] To further enhance the anti-interference capability of current step event detection, a dual verification mechanism in the time dimension is introduced based on the above scheme. Optionally, the method also includes: determining the execution time of the operating condition command and the abrupt change time of the current signal; determining the time difference between the execution time and the abrupt change time; and determining that a current step has occurred in the grounding circuit when the current change rate exceeds a target threshold, including: determining that a current step has occurred in the grounding circuit when the current change rate exceeds the target threshold and the time difference is less than the target time difference.

[0082] The execution time refers to the instantaneous point in time when the operating condition command is executed. The abrupt change time refers to the instantaneous point in time when the current signal undergoes a rapid change. For example, the timestamp of the inflection point where the current value jumps from a steady state to a new steady state.

[0083] In practice, the timestamp of the issuance of the operating condition command is obtained and used as the execution time. Differential processing is performed on the current signal to identify the time point when the current signal amplitude changes abruptly, which is then taken as the abrupt change time. The absolute value of the difference between the two timestamps is calculated to obtain the time difference. When the time difference is less than the target time difference (e.g., 2ms) and the current change rate exceeds the target threshold, it indicates that the current abrupt change is a genuine current step caused by the execution of the operating condition command, rather than a random interference signal, thus initiating the subsequent data acquisition and calculation process.

[0084] If the time difference is greater than or equal to the target time difference, or the current change rate does not exceed the target threshold, it indicates that the current change is not a valid current step triggered by the operating condition command and does not meet the detection triggering condition. The current detection process will end directly and wait for the next operating condition command before re-judging.

[0085] For example, when the vehicle controller issues a torque increase command, if the current change rate is detected to reach 180 amperes per millisecond after 1ms, which meets the current change rate threshold requirement, and the time difference of 1ms is less than the target time difference of 2ms, then a valid current step is determined to have occurred, triggering subsequent detection and calculation; if the current change rate meets the requirement, but the time difference is 5ms, which is greater than the target time difference, then it indicates that the current change is unrelated to the operating condition command and is an interference signal, and detection is not triggered.

[0086] This application combines the time difference between the execution time and the sudden change time with the current change rate to verify whether the current change is a real current step caused by the execution of the operating condition command, thereby eliminating interference such as random noise and false touch signals, effectively improving the accuracy of current step judgment, avoiding invalid detection, and ensuring the reliability of the entire detection process.

[0087] To avoid using low-quality data containing abnormal data acquisition or external strong pulse interference in subsequent calculations, which could affect the accuracy of the contact resistance component, this application also introduces a data validity verification and resampling mechanism. Specifically, before determining the transient equivalent resistance of the grounding point over at least two time windows based on current and voltage data, the mechanism further includes: determining whether there is an abnormal current jump exceeding a target jump threshold between consecutive sampling points within the time window based on the current data; if an abnormal current jump exists, or the voltage data exceeds the target voltage range, then in the event of a current step in the grounding circuit, the current and voltage data at the grounding point are reacquired.

[0088] Continuous sampling points refer to adjacent sampling points collected sequentially within the same time window. The target jump threshold is used to determine the upper limit of the amplitude of any abnormal current change between continuous sampling points. For example, the target jump threshold is defined as the maximum allowable current change between continuous sampling points, such as 50A. The target voltage range refers to the reasonable range that the ground voltage should be within under normal operating conditions. For example, the target voltage range is 0~5V.

[0089] In practice, if the current jump amplitude between any two consecutive sampling points exceeds the target jump threshold, it indicates that the current data may be affected by external strong pulse interference, resulting in insufficient data validity. Similarly, if the collected voltage data exceeds the target voltage range for normal operation of the grounding point, it indicates that the acquisition process may be abnormal, leading to low data reliability. In such cases, the data re-acquisition process is triggered whenever any of the above abnormalities occur. Under the next current step change, current and voltage data are re-acquired until a continuous and smooth data segment is obtained.

[0090] Furthermore, if the number of resampling attempts exceeds the preset threshold and no data is obtained that does not exhibit abnormal current fluctuations and is within the target voltage range, the current detection process will be terminated, and a data acquisition anomaly fault code will be reported to the vehicle controller to remind the driver or maintenance personnel to check the acquisition circuit and avoid misjudgment due to invalid data.

[0091] For example, if, within the rising edge time window, there are multiple sets of consecutive sampling points experiencing abnormal current jumps exceeding 50A, or if the collected grounding voltage data exceeds the range of 0-5V, it is necessary to wait for the next current step event to occur before re-collecting the current and voltage data for that grounding point. If, after three resampling attempts, data meeting the validity requirements is still not obtained, the current detection is terminated, and a fault code indicating an abnormal acquisition is reported, prompting relevant personnel to investigate the hardware connections and signal transmission lines of the voltage and current acquisition circuit.

[0092] This application embodiment verifies the validity of current and voltage data collected within a time window, promptly identifies data with interference or abnormal collection, and ensures the quality of data used in subsequent calculations by triggering a re-sampling mechanism. This avoids the impact of low-quality data on the calculation results and improves the reliability and accuracy of the contact resistance component calculation results.

[0093] The embodiments of the vehicle condition detection method have been described in detail above. In order to enable those skilled in the art to further understand the technical solution of this method, the following section will provide a detailed explanation in the context of online monitoring of poor high-voltage grounding contact in new energy vehicles.

[0094] When a user presses the accelerator pedal while a new energy vehicle is in motion, the vehicle controller responds to the drive command and instantly sends a torque request to the ground circuit, and the power battery begins to supply a large current to the drive motor.

[0095] The vehicle's battery management system monitors the current signal in the high-voltage circuit in real time and continuously acquires the operating condition commands from the vehicle controller via the controller area network bus. When the rate of change of the current signal exceeds the preset 150A / ms, and the time difference between the moment of the current change and the moment of command execution by the vehicle controller does not exceed 2ms, it is confirmed that the current is in a step current condition. Then, based on the moment of command execution, a time window with a duration of 8 milliseconds is locked.

[0096] Within this time window, the ground voltage analog-to-digital converter channel of the Hall current sensor and the microcontroller unit is reused to synchronously acquire current and voltage data at the grounding point at a frequency of 20 kHz. Based on the directional characteristics of the current's sharp forward increase and reverse drop, the time window is divided into rising edge and falling edge time windows. The acquisition process does not require any additional sensors or excitation circuits on the vehicle, achieving non-intrusive monitoring at the pure software level.

[0097] Furthermore, the data acquired within the rising and falling edge time windows undergoes instruction verification. Specifically, it is determined whether there are abnormal current jumps exceeding the target threshold between consecutive sampling points within the rising and falling edge time windows, and whether the voltage data exceeds the target voltage range. If an abnormal current jump or exceeding the target voltage range occurs, it indicates that the current and voltage data are invalid data caused by instantaneous sensor anomalies or external strong pulse interference. The acquisition results will be discarded, and data acquisition will be retried when the next current step event occurs, thereby preventing inferior data from affecting the calculation results.

[0098] After data verification, the transient equivalent resistance at the rising edge is calculated based on the voltage and current changes corresponding to the rising edge time window. Similarly, the transient equivalent resistance at the falling edge is calculated based on the voltage and current changes corresponding to the falling edge time window. Both of these transient equivalent resistances can be physically decomposed into two parts: a contact resistance component reflecting the true physical state of the grounding point, and a parasitic inductance voltage component introduced by the induced voltage generated by the parasitic inductance of the high-voltage harness during current transients.

[0099] Then, the transient equivalent resistance at the rising edge and the transient equivalent resistance at the falling edge are added together, and half of the absolute value is taken as the contact resistance component. During this calculation, the positive induced voltage generated by the parasitic inductance at the rising edge of the current and the reverse induced voltage generated at the falling edge of the current cancel each other out during the addition process. The contact resistance voltage is retained because its direction is always consistent with the current direction.

[0100] The vehicle's grounding circuit has grounding points at several key locations, including the battery negative terminal, motor housing, and fast charging port. The aforementioned data acquisition and contact resistance component determination process was performed for each grounding point. For each grounding point, a corresponding target resistance component was determined as a warning threshold based on the cross-sectional area of ​​the high-voltage harness conductor it connects to. For example, for a 25 square millimeter cross-sectional area motor high-voltage harness, the corresponding threshold is 0.4 mV / A; for a 50 square millimeter cross-sectional area fast charging harness, the corresponding threshold is 0.25 mV / A. By setting the threshold according to the negative correlation between cross-sectional area and target resistance component, it can be ensured that the judgment threshold for different harness specifications matches their actual needs, avoiding misjudgments caused by fixed thresholds.

[0101] Furthermore, if the contact resistance component of the motor housing grounding point exceeds the target resistance component, it does not simply issue a single circuit bus alarm. Instead, it compares the contact resistance component of that motor housing grounding point with the contact resistance components of other grounding points in the same grounding circuit, such as the battery negative grounding point and the fast charging port grounding point. Through analysis, it is found that only the component of the motor housing grounding point is high, while the values ​​of other grounding points remain normal. This accurately pinpoints the poor contact fault to the motor housing grounding point.

[0102] Finally, a tiered warning signal is output via the bus. For example, a level-two warning is issued for the early deterioration of the motor housing grounding point, alerting maintenance personnel to the issue. Simultaneously, complete data from this fault detection, including current step waveform characteristics, contact resistance components at each grounding point, and the final conclusion, is written into non-volatile memory for easy future reference. The entire process, from current step triggering to warning location completion, takes less than ten milliseconds, is completely unnoticed by the user, and does not affect the vehicle's normal driving operation.

[0103] In this scenario, the embodiment of this application achieves accurate identification and location of an initial contact degradation point within 8 milliseconds without any hardware modifications, and can identify resistance degradation at the level of 0.1mΩ; thus avoiding accidents caused by overheating or even burnout due to deterioration of contact resistance, and improving the safety and reliability of vehicle use.

[0104] The above text combined Figure 1 The present application describes in detail the vehicle state detection method embodiments, which are illustrated below in conjunction with... Figure 2 This application provides a detailed description of embodiments of the vehicle condition detection device. It should be understood that the descriptions of the vehicle condition detection method embodiments correspond to the descriptions of the vehicle condition detection device embodiments; therefore, any parts not described in detail can be found in the preceding method embodiments.

[0105] Figure 2 The diagram shown is a structural schematic of a vehicle condition detection device provided in an embodiment of this application. Figure 2As shown, the vehicle condition detection device 20 provided in this application embodiment includes: The data acquisition module 210 is used to acquire current and voltage data at the grounding point of the grounding circuit when a current step occurs in the grounding circuit. The resistance determination module 220 is used to determine the transient equivalent resistance of the grounding point in at least two time windows based on current data and voltage data; wherein, the transient equivalent resistance is the ratio of voltage change to current change, which can be decomposed into the contact resistance component and the parasitic inductance voltage component of the grounding point. The numerical calculation module 230 is used to cancel the parasitic inductance voltage component by performing numerical calculation on the transient equivalent resistance of at least two time windows, and obtain the contact resistance component of the grounding point. The status determination module 240 is used to determine the contact status of the grounding point of the grounding circuit based on the contact resistance component of the grounding point.

[0106] In one embodiment of this application, at least two time windows include the rising edge time window and the falling edge time window in the same step event; the numerical calculation module 230 is further configured to calculate the transient equivalent resistance of the rising edge time window and the arithmetic mean of the transient equivalent resistance of the falling edge time window to offset the parasitic inductance voltage component and obtain the contact resistance component of the grounding point.

[0107] In one embodiment of this application, there are multiple grounding points; the state determination module 240 is further configured to, for any grounding point, if the contact resistance component of the grounding point exceeds the target resistance component, compare the contact resistance component of the grounding point with the contact resistance components of the remaining grounding points, and determine the contact state of the grounding point based on the comparison result.

[0108] In one embodiment of this application, the state determination module 240 is further configured to determine the target resistance component based on the cross-sectional area of ​​the conductor in the grounding circuit; wherein the cross-sectional area is negatively correlated with the target resistance component.

[0109] In one embodiment of this application, the state determination module 240 is further configured to determine the maximum component from the contact resistance components of each remaining grounding point; if the contact resistance component of the grounding point exceeds the maximum component of the target multiple, and the difference between the contact resistance components of each remaining grounding point is less than the target difference, then the contact state is determined to be a fault state.

[0110] In one embodiment of this application, the device further includes: a signal acquisition module, configured to acquire the current signal of the grounding circuit in response to the operating condition command of the vehicle controller; determine the rate of change of the current signal; and determine that a current step has occurred in the grounding circuit when the rate of change of the current exceeds a target threshold.

[0111] In one embodiment of this application, the signal acquisition module is further configured to: determine the execution time of the operating condition command and the abrupt change time of the current signal; determine the time difference between the execution time and the abrupt change time; and determine that a current step has occurred in the grounding circuit when the current change rate exceeds a target threshold and the time difference is less than the target time difference.

[0112] In one embodiment of this application, the device further includes: a reacquisition module, used to determine whether there is an abnormal current jump exceeding a target jump threshold between consecutive sampling points within a time window, based on the current data, before determining the transient equivalent resistance of the grounding point within at least two time windows based on the current data and voltage data; if there is an abnormal current jump, or the voltage data exceeds the target voltage range, then in the event of a current step in the grounding circuit, the current data and voltage data at the grounding point are reacquisitioned.

[0113] This application embodiment collects current and voltage data when the grounding circuit is in a current step state. Compared with the steady-state condition, the current change rate is larger under current step conditions. The larger current change amplifies the signal generated by the contact resistance, making the voltage change characterizing the contact resistance more prominent and effectively preventing early degradation signals from being drowned out by system noise. At the same time, by numerically calculating the transient equivalent resistance of at least two time windows, the interference of voltage components generated by parasitic inductance is canceled, and the contact resistance component that can accurately reflect the contact state of the grounding point is obtained, thereby accurately judging the contact state of the grounding point. Therefore, this application embodiment improves the sensitivity and accuracy of grounding point state detection, can detect early contact degradation problems in a timely manner, reduce the risk of missed detection, and effectively ensure the reliability and safety of the grounding circuit operation.

[0114] It is worth noting that in the above embodiments of the vehicle status detection device, the various units and modules included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of each functional unit are only for easy differentiation and are not used to limit the scope of protection of the present invention.

[0115] Below, for reference Figure 3 To describe the vehicle according to embodiments of this application. Figure 3 The diagram shown is a structural schematic of a vehicle provided in an exemplary embodiment of this application.

[0116] like Figure 3 As shown, vehicle 30 includes one or more processors 301 and memory 302.

[0117] The processor 301 may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the vehicle 30 to perform desired functions.

[0118] The memory 302 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory. Non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 301 may execute the program instructions to implement the vehicle state detection methods of the various embodiments of this application described above and / or other desired functions.

[0119] In one example, vehicle 30 may also include input device 303 and output device 304, which are interconnected via a bus system and / or other forms of connection mechanism (not shown).

[0120] The input device 303 may include, for example, a keyboard, a mouse, etc.

[0121] The output device 304 can output various information to the outside. The output device 304 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0122] Of course, for the sake of simplicity, Figure 3 Only some of the components of vehicle 30 relevant to this application are shown in this illustration; components such as buses, input / output interfaces, etc., are omitted. In addition, vehicle 30 may include any other suitable components depending on the specific application.

[0123] In addition to the methods and apparatus described above, embodiments of this application may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the vehicle state detection methods according to various embodiments of this application as described above.

[0124] Computer program products can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0125] Furthermore, embodiments of this application may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps in the vehicle state detection methods according to various embodiments of this application described above.

[0126] Computer-readable storage media may take the form of any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may, for example, include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0127] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details of the above application are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0128] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0129] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0130] The above description of the claimed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be applied within the widest scope consistent with the principles and novel features of this application.

[0131] The above description has been given for illustrative and descriptive purposes. Furthermore, this description is not intended to limit the embodiments of this application to the forms described herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A vehicle condition detection method, characterized in that, include: When a current step occurs in the grounding circuit, collect the current and voltage data at the grounding point of the grounding circuit; Based on the current data and the voltage data, the transient equivalent resistance of the grounding point is determined in at least two time windows; wherein, the transient equivalent resistance is the ratio of the voltage change to the current change, and can be decomposed into the contact resistance component and the parasitic inductance voltage component of the grounding point. The contact resistance component of the grounding point is obtained by numerically calculating the transient equivalent resistance of at least two time windows to cancel out the parasitic inductance voltage component. The contact state of the grounding point in the grounding circuit is determined based on the contact resistance component of the grounding point.

2. The method of claim 1, wherein, The at least two time windows include the rising edge time window and the falling edge time window in the same step event; The step of numerically calculating the transient equivalent resistance of at least two time windows to cancel out the parasitic inductance voltage component and obtaining the contact resistance component of the grounding point includes: The transient equivalent resistance of the rising edge time window and the transient equivalent resistance of the falling edge time window are calculated as an arithmetic mean to cancel out the parasitic inductance voltage component, thereby obtaining the contact resistance component of the grounding point.

3. The method of claim 1, wherein, The number of grounding points is multiple; determining the contact state of the grounding points in the grounding circuit based on the contact resistance components of the grounding points includes: For any of the grounding points, if the contact resistance component of the grounding point exceeds the target resistance component, the contact resistance component of the grounding point is compared with the contact resistance components of the remaining grounding points, and the contact state of the grounding point is determined based on the comparison result.

4. The method of claim 3, wherein, Also includes: The target resistance component is determined based on the cross-sectional area of ​​the conductor in the grounding circuit; The cross-sectional area is negatively correlated with the target resistance component.

5. The method of claim 3, wherein, Determining the contact state of the grounding point based on the comparison result includes: The maximum component is determined from the contact resistance components of each of the remaining grounding points; If the contact resistance component at the grounding point exceeds the maximum component of the target multiple, and the difference between the contact resistance components of each of the remaining grounding points is less than the target difference, then the contact state is determined to be a fault state. Wherein, the target multiple is greater than 1.

6. The method of claim 1, wherein, Also includes: In response to the operating condition commands of the vehicle controller, the current signal of the grounding circuit is acquired; Determine the rate of change of the current signal; If the rate of change of current exceeds the target threshold, it is determined that a current step has occurred in the grounding circuit.

7. The method of claim 6, wherein, Also includes: Determine the execution time of the operating condition command and the abrupt change time of the current signal; Determine the time difference between the execution time and the mutation time; The step of determining that a current step has occurred in the grounding circuit when the rate of change of current exceeds a target threshold includes: If the rate of change of current exceeds the target threshold and the time difference is less than the target time difference, it is determined that a current step has occurred in the grounding circuit.

8. The method of claim 1, wherein, Before determining the transient equivalent resistance of the grounding point over at least two time windows based on the current data and the voltage data, the method further includes: Based on the current data, determine whether there is an abnormal current jump exceeding the target jump threshold between consecutive sampling points within the time window; If there is an abnormal current jump, or if the voltage data exceeds the target voltage range, then if a current step occurs in the grounding circuit, the current and voltage data at the grounding point will be re-acquired.

9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program for executing the vehicle state detection method according to any one of claims 1 to 8.

10. A vehicle characterized by comprising: include: processor; Memory used to store the processor's executable instructions; The processor is used to execute the vehicle state detection method according to any one of claims 1 to 8.

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