A fault diagnosis method and device for electric vehicle current stagnation

Abstract

The present invention discloses a fault diagnosis method and device for electric vehicle current jam. The fault diagnosis method includes: in driving mode, when at least one state parameter of the electric vehicle changes, determining a first expected current range based on the state parameters before and after the change and the battery current before the change, wherein the state parameter includes at least one of the battery voltage, the vehicle speed, and the opening of the accelerator pedal. Determining whether current jam has occurred based on the first expected current range and the battery current after the change. If the number of current jams within a single preset cycle reaches a preset number, it is determined that the electric vehicle has a jam fault. If the number of current jams within a single preset cycle does not reach a preset number, it is determined that the electric vehicle has not a jam fault and the number of current jams is reset to zero. The solution of the present invention can reduce the amount of data required and the conditions for triggering judgment, and improve the accuracy of fault diagnosis.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of automobile control technology, and in particular to a fault diagnosis method and device for electric vehicle current stagnation. Background Art

[0002] In recent years, with the rapid development of energy storage technology, the electric vehicle industry has attracted more and more attention from companies and has become a hot industry.

[0003] In the on-board system of a traditional car, when the vehicle speed exceeds a preset value, the accelerator pedal opening signal is obtained, and then the opening signal is compared with the historical opening signal at the same vehicle speed to determine whether the accelerator pedal is stuck.

[0004] However, traditional stuck judgment methods have harsh triggering conditions, large data requirements and low accuracy, making them unsuitable for application in electric vehicles with higher safety requirements. Summary of the Invention

[0005] The present invention provides a method and device for diagnosing electric vehicle current stuck faults, so as to reduce data requirements and trigger judgment conditions, and improve the accuracy of fault diagnosis.

[0006] In a first aspect, an embodiment of the present invention provides a method for diagnosing a fault of electric vehicle current stuck, the method comprising:

[0007] In the driving mode, when at least one state parameter of the electric vehicle changes, determining a first expected current range based on the state parameters before and after the change and the battery current before the change, wherein the state parameter includes at least one of the battery voltage, the vehicle speed, and the opening of the accelerator pedal;

[0008] determining whether current jamming occurs according to the first expected current range and the changed battery current;

[0009] If the number of times the current is stuck reaches a preset number within a single preset cycle, it is determined that a stuck fault occurs in the electric vehicle;

[0010] If the number of current jams within a single preset cycle does not reach a preset number, it is determined that no jam fault occurs in the electric vehicle and the number of current jams is reset to zero.

[0011] Optionally, in the driving mode, when at least one state parameter of the electric vehicle changes, before determining the first expected current range based on the state parameters before and after the change and the battery current before the change, the method further includes:

[0012] In a standby state, whether the current jam occurs is determined based on the battery voltage and the battery current.

[0013] Optionally, after determining whether current jam occurs according to the battery voltage and the battery current, the method further includes:

[0014] Entering different operating modes of the electric vehicle according to at least one of the state parameters, wherein the operating modes include the driving mode and the charging mode;

[0015] In the charging mode, whether the current jam occurs is determined based on the battery voltage and the battery current.

[0016] Optionally, determining whether current jam occurs according to the battery voltage and the battery current includes:

[0017] detecting the battery voltage and battery current;

[0018] When the battery voltage undergoes a pulse change, determining whether the battery current changes with the battery voltage;

[0019] If the battery current does not change with the battery voltage, it is determined that current stuck occurs.

[0020] Optionally, when the battery voltage undergoes a pulse change, determining whether the battery current changes with the battery voltage includes:

[0021] When a change in the battery voltage within a preset period exceeds a preset voltage value, determining a second expected current range according to the battery voltage before and after the change and the battery current before the change;

[0022] If the changed battery current reaches the second expected current range, determining that the battery current changes with the battery voltage;

[0023] If the changed battery current does not reach the second expected current range, it is determined that the battery current does not change with the battery voltage.

[0024] Optionally, after determining that the electric vehicle has a stuck fault and determining that the electric vehicle has not a stuck fault, the method further includes:

[0025] Determining whether the electric vehicle has exited operation;

[0026] If the electric vehicle is out of operation, then the diagnostic method ends;

[0027] If the electric vehicle has not exited operation, the operation mode of the electric vehicle is returned to a different operation mode according to at least one of the state parameters.

[0028] Optionally, when the electric vehicle is in the driving mode and at least one state parameter of the electric vehicle changes, determining the first expected current range according to the state parameters before and after the change and the battery current includes:

[0029] When the vehicle speed changes, determining a first change ratio according to a ratio of the vehicle speeds before and after the change;

[0030] The first expected current range is determined according to the first change ratio and the battery current before the change.

[0031] Optionally, when the electric vehicle is in the driving mode and at least one state parameter of the electric vehicle changes, determining the first expected current range according to the state parameters before and after the change and the battery current includes:

[0032] When the opening changes, determining a second change ratio according to the ratio of the openings before and after the change;

[0033] The first expected current range is determined according to the second change ratio and the battery current before the change.

[0034] Optionally, when the battery voltage undergoes a pulse change, determining a second expected current range according to the battery voltage before and after the change and the battery current before the change includes:

[0035] When the battery voltage undergoes a pulse change, determining a third change ratio according to a ratio of the battery voltage before and after the change;

[0036] The second expected current range is determined according to the third change ratio and the battery current before the change.

[0037] In a second aspect, embodiments of the present invention further provide a device for diagnosing electric vehicle current stuck faults. The device comprises: a first expected current range determination unit, a current stuck determination unit, and a stuck fault judgment unit. The first expected current range determination unit is configured to, when at least one state parameter of the electric vehicle changes in driving mode, determine a first expected current range based on the state parameters before and after the change and the battery current before the change, wherein the state parameters include battery voltage, vehicle speed, and accelerator pedal opening. The current stuck determination unit is configured to determine whether current stuck occurs based on the first expected current range and the battery current after the change. The stuck fault judgment unit is configured to determine that a stuck fault has occurred in the electric vehicle if the number of current stuck events within a single preset cycle reaches a preset number, and to determine that no stuck fault has occurred in the electric vehicle and reset the number of current stuck events to zero if the number of current stuck events within a single preset cycle does not reach the preset number.

[0038] The present embodiment provides a method and device for diagnosing electric vehicle current stuck faults. During driving, if a state parameter changes, a first expected current range is determined based on the state parameters before and after the change and the battery current before the change. Current stuck is then determined based on the first expected current range and the battery current after the change. If the number of current stuck events in a single preset cycle reaches a preset number, the electric vehicle is determined to have a stuck fault. If the number of current stuck events in a single preset cycle does not reach the preset number, the electric vehicle is determined not to have a stuck fault within the preset cycle and the number of current stuck events is reset to zero. This facilitates diagnosis of stuck faults in the electric vehicle's driving mode. Each current stuck fault determination in this process is based solely on the state parameters and battery current before and after a single change, eliminating the need for extensive historical data comparison and reducing data requirements. Each current stuck fault determination is performed when the state parameter changes, eliminating the need to reach a certain speed and requiring a low triggering condition. The use of the preset cycle and number of current stuck faults in the stuck fault diagnosis process reduces false stuck alarms caused by sensor signal errors and improves fault diagnosis accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A flow chart of a method for diagnosing a current stuck fault in an electric vehicle provided by an embodiment of the present invention;

[0040] Figure 2 A flow chart of another method for diagnosing electric vehicle current stuck faults provided by an embodiment of the present invention;

[0041] Figure 3 A schematic flow chart of another method for diagnosing electric vehicle current stuck faults provided by an embodiment of the present invention;

[0042] Figure 4 A schematic flow chart of a method for determining a first expected current range in a driving mode provided by an embodiment of the present invention;

[0043] Figure 5 A schematic flow chart of a method for determining a first expected current range in a standby state or a charging mode provided by an embodiment of the present invention;

[0044] Figure 6 A schematic structural diagram of a fault diagnosis device for electric vehicle current stagnation provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0046] In order to solve the problem raised in the background art, an embodiment of the present invention provides a fault diagnosis method for electric vehicle current stagnation. Figure 1 A flow chart of a fault diagnosis method for electric vehicle current stuck provided by an embodiment of the present invention, referring to Figure 1 , the fault diagnosis methods for electric vehicle current stagnation include:

[0047] S101. In a driving mode, when at least one state parameter of an electric vehicle changes, determine a first expected current range according to the state parameters before and after the change and the battery current before the change.

[0048] Among them, the state parameter refers to the parameter value that can reflect the state of the electric vehicle such as the speed of travel and the battery power supply efficiency. The state parameter includes at least one of the battery voltage, vehicle speed and the opening of the accelerator pedal. The driving mode refers to the mode corresponding to the electric vehicle when the electric vehicle is in the process of moving. In this driving mode, the speed of the electric vehicle is not 0. The battery voltage refers to the voltage across the energy storage battery. The battery current refers to the power supply current of the energy storage battery in the electric vehicle to other electrical appliances or the charging current provided by the charger to the energy storage battery. The electrical appliances may include power motors, air conditioners, indicator lights and any other on-board electrical appliances. The first expected current range refers to the numerical range of the output current of the energy storage battery as the state parameters change.

[0049] Specifically, in driving mode, the vehicle control system can obtain the electric vehicle's speed via a speed sensor and the accelerator pedal position via a position sensor. The vehicle control system is in communication with the battery management system and can obtain battery status parameters such as the voltage and state of charge of the energy storage battery. Whether a status parameter has changed can be determined based on the relative relationship between the change in the status parameter (or the rate of change) and the corresponding threshold. The status parameter acquisition cycle can be set according to actual needs, or the determination can be made based on real-time status parameters. For example, if the real-time battery voltage changes by 3V within 5 seconds, exceeding the voltage threshold of 2V, the vehicle control system can determine that the battery voltage has changed. If it is determined that at least one status parameter of the electric vehicle has changed, the increase in the status parameter can be determined based on the status parameters before and after the change. Furthermore, based on the increase in the status parameter and the battery current before the change, a first expected current range for the battery current after the change can be determined. The first expected current range refers to the expected range of the battery current after the change caused by the change in the status parameter. For example, in driving mode, with other state parameters unchanged, if the speed of an electric vehicle decreases from 50 km / h to 40 km / h due to road conditions, the first expected current range after the speed change can be determined based on the relative relationship between battery current and vehicle speed obtained in an experiment. If, with other state variables unchanged, the percentage of vehicle speed reduction equals the percentage of battery current increase, and the battery current is 10 A at a speed of 50 km / h, the first expected current range can include 10*(1+1 / 5)=12 A. Preferably, the first expected range can be 11.5 A-12.5 A.

[0050] For example, an electric vehicle is traveling steadily with a battery voltage of 18V, a speed of 50km / h, and an accelerator pedal opening of 30%. At this point, the battery current is 10A. Then, due to a downhill slope, the vehicle speed increases from 50km / h to 60km / h. If the battery voltage remains at 18V and the accelerator pedal opening remains at 30%, the first expected current range may include 10*(1-1 / 5)=8A.

[0051] S102: Determine whether current jamming occurs according to the first expected current range and the changed battery current.

[0052] Specifically, the relative relationship between the first expected current range and the changed battery current is compared, and the difference between the first expected current range and the changed battery current is calculated. Based on the relative relationship between the first expected current range and the changed battery current, it can be determined whether the electric vehicle has experienced current stuck. For example, if the changed battery current is not within the first expected current range, it indicates that the battery current has not changed with changes in the state parameter, and thus, it can be determined that the electric vehicle has experienced current stuck. If the changed battery current is within the first expected current range, it indicates that the battery current has changed with changes in the state parameter, and thus, it can be determined that the electric vehicle is operating normally and that current stuck has not occurred during this change in the state parameter. Current stuck can reflect a mismatch between the pedal depression angle and the pedal output signal, an abnormality in the transmission of the pedal output signal, an abnormality in the relative relationship between the voltage and current of the energy storage battery, an abnormality in the transmission of the vehicle speed signal, and a variety of other faults.

[0053] For example, if the battery current before a speed change is 8A, and the corresponding first expected current range after the change is 9.8A-10.2A, but the actual battery current after the change is 8.5A, and the changed battery current is not within the first expected current range, it can be further determined that the electric vehicle has experienced current stagnation during this speed change. The number of current stagnation events within a single preset cycle is incremented by one.

[0054] S103: Determine whether the preset period has ended based on the time.

[0055] Specifically, after each determination of whether current stuck occurs, it is necessary to determine whether the end of a preset period has been reached based on the time. If the end of the preset period has been reached, it is necessary to determine whether the number of current stuck events within a single preset period has reached a preset number. If the end of the preset period has not been reached, the process returns to step S101 to continue determining whether current stuck occurs and to accumulate the number of current stuck events within the preset period.

[0056] S104: Determine whether the number of current jams within a single preset cycle has reached a preset number.

[0057] S105: If the number of current jams within a single preset cycle reaches a preset number, it is determined that a jam fault occurs in the electric vehicle.

[0058] Among them, the preset period refers to the current jam counting period for judging whether a jam fault occurs, and the preset number of times refers to the current jam count threshold for judging whether an electric vehicle has a jam fault within a single preset period. The preset period and the preset number of times are both related to the acquisition error rate of the sensor device for obtaining status parameters on the electric vehicle.

[0059] Specifically, in the process of collecting state parameters, the sensor device on the electric vehicle will be affected by the driving mode, environment, its own structure and other factors, resulting in a certain error rate in the sensor signal obtained by the sensor device and uploaded to the vehicle control system. In order to avoid false alarms of jams caused by errors in the sensor signal, this application sets a preset cycle and preset number of times based on empirical values ​​and sensor signal error rate experiments. Within a single preset cycle, the preset number of times is made greater than the number of sensor signal errors measured experimentally to prevent false alarms of jams caused by sensor signal errors. Within a single preset cycle, if the number of current jams is greater than or equal to the preset number of times, the current jam is not caused by sensor signal errors, and it can be determined that the electric vehicle has a jam fault.

[0060] S106: If the number of current stuck events within a single preset cycle does not reach a preset number, it is determined that the electric vehicle does not have a stuck fault and the number of current stuck events is reset to zero.

[0061] Specifically, if the number of current stuck events within a single preset cycle does not reach the preset number, the current stuck event within that preset cycle can be determined to be caused by a sensor signal error, and the electric vehicle can be determined to have not experienced a stuck fault within that preset cycle. For example, the preset period can be 10 seconds, and the preset number of events can be 2. If the number of current stuck events within a single preset cycle does not reach the preset number, the current stuck count can be reset to zero, and the process proceeds to the next preset cycle.

[0062] The present embodiment provides a method for diagnosing electric vehicle current stuck faults. During driving, if a state parameter changes, a first expected current range is determined based on the state parameters before and after the change and the battery current before the change. Current stuck is then determined based on the first expected current range and the battery current after the change. If the number of current stuck events in a single preset cycle reaches a preset number, the electric vehicle is determined to have a stuck fault. If the number of current stuck events in a single preset cycle does not reach the preset number, the electric vehicle is determined not to have a stuck fault within the preset cycle and the number of current stuck events is reset to zero. This method enables the diagnosis of stuck faults in the electric vehicle driving mode. Each current stuck determination in this process is based solely on the state parameters and battery current before and after a single change, eliminating the need for extensive historical data comparison and reducing data requirements. Each current stuck determination is performed when the state parameter changes, without requiring a certain speed to be reached, and the triggering condition for the determination is relatively low. The use of the preset cycle and number of current stuck events in the stuck fault diagnosis process reduces false stuck alarms caused by sensor signal errors and improves the accuracy of fault diagnosis.

[0063] Optionally, Figure 2 A flow chart of another electric vehicle current stuck fault diagnosis method provided by an embodiment of the present invention, referring to Figure 2 Based on the above embodiment, the fault diagnosis method for electric vehicle current stagnation may further include:

[0064] S201 : In a standby state or a charging mode, determine whether current jam occurs based on the battery voltage and the battery current.

[0065] The standby state refers to the waiting state of the electric vehicle after it is powered on. In the standby state, the speed of the electric vehicle is 0 and the energy storage battery is not charging. The charging mode refers to the mode in which the electric vehicle is connected to the charging device. In this state, the speed of the energy storage battery is 0 and the battery voltage is equal to the charging voltage.

[0066] Specifically, when the electric vehicle is in standby or charging mode, the battery voltage and battery current are obtained. If the battery voltage undergoes a pulse change, a determination is made as to whether the battery current varies with the battery voltage. A pulse change refers to a large voltage change within a short period of time. For example, a pulse change may be when the battery voltage changes by more than a preset voltage value within a preset time period. The preset time period may be 1 second, and the preset voltage value may be 10V. If the battery current varies with the battery voltage, then the battery current is not stuck. If the battery current does not vary with the battery voltage, then the battery current is stuck.

[0067] For example, when an electric vehicle is in standby mode and a user connects the electric vehicle to a charging device, the total voltage across the electric vehicle's energy storage battery may pulse. S201. In standby mode or charging mode, determining whether current jamming occurs based on the battery voltage and battery current may include: S2011. In standby mode, detecting whether the battery voltage of the electric vehicle undergoes pulse jamming. S2012. When the battery voltage undergoes pulse jamming, determining whether the battery current varies with the battery voltage. S2013. If the battery current does not vary with the battery voltage, determining that current jamming has occurred. S2014. If the battery current varies with the battery voltage, determining that current jamming has not occurred. Preferably, when the battery voltage undergoes pulse jamming, a second expected current range is determined based on the battery voltage before and after the variation and the battery current before the variation. If the variation in the battery current reaches the second expected current range, determining that the battery current has varied with the battery voltage. If the variation in the battery current does not reach the second expected current range, determining that the battery current has not varied with the battery voltage, and further determining that current jamming has occurred. The relationship between the battery voltage before and after the change, the battery current before the change, and the battery current after the change can be measured experimentally, so that the relationship can be used to determine the second expected current range.

[0068] S202: Determine whether the preset period has ended based on the time.

[0069] Specifically, after each determination of whether current stuck occurs, it is necessary to determine whether the end of a preset period has been reached based on the time. If the end of the preset period has been reached, it is necessary to determine whether the number of current stuck events within a single preset period has reached a preset number. If the end of the preset period has not been reached, the process returns to step S201 to continue determining whether current stuck occurs and to accumulate the number of current stuck events within the preset period.

[0070] S203: Determine whether the number of current jams in a single preset cycle has reached a preset number.

[0071] S204: If the number of current jams within a single preset cycle reaches a preset number, it is determined that a jam fault occurs in the electric vehicle.

[0072] S205: If the number of current stuck events within a single preset cycle does not reach the preset number, it is determined that the electric vehicle does not have a stuck fault and the number of current stuck events is reset to zero.

[0073] Steps S203 , S204 and S205 have the same contents as steps S104 , S105 and S106 , and are not described again here.

[0074] This embodiment provides a flow chart of a method for diagnosing electric vehicle current stuck faults. When the electric vehicle is in standby or charging mode, current stuck is determined based on the battery voltage and current. If the number of current stuck events reaches a preset number within a single preset cycle, a stuck fault is determined. If the number of current stuck events does not reach the preset number within a single preset cycle, the electric vehicle is determined not to have stuck, the number of current stuck events is reset to zero, and the next preset cycle is entered. Current stuck is determined based on the battery voltage and current. This method effectively detects stuck faults in the standby and charging modes of the electric vehicle. Each current stuck determination in this process is based solely on the battery voltage and current before and after a single change, eliminating the need for extensive historical data comparison and reducing data requirements. Each current stuck determination is performed when the state parameters change, eliminating the need to reach a certain speed and requiring a low triggering condition. The use of the preset cycle and number of current stuck detections reduces false stuck alarms caused by sensor signal errors and improves fault diagnosis accuracy.

[0075] Optionally, Figure 3 A flow chart of another method for diagnosing a fault of electric vehicle current stuck provided by an embodiment of the present invention is shown in FIG. Figure 3 Based on the above embodiment, the fault diagnosis method for electric vehicle current stagnation includes:

[0076] S301 : In a standby state, determine whether current jam occurs based on the battery voltage and the battery current.

[0077] The standby state refers to the waiting state of the electric vehicle after it is powered on. In the standby state, the speed of the electric vehicle is 0 and the energy storage battery is not charged.

[0078] Specifically, when the electric vehicle is in standby mode, the battery voltage and battery current are obtained. If the battery voltage undergoes a pulse change, a determination is made as to whether the battery current varies with the battery voltage. A pulse change refers to an excessively large voltage change within a short period of time. For example, a pulse change may be when the battery voltage changes by more than a preset voltage value within a preset time period. The preset time period may be 1 second, and the preset voltage value may be 10V. If the battery current varies with the battery voltage, then the battery current is not stuck. If the battery current does not vary with the battery voltage, then the battery current is stuck.

[0079] For example, when an electric vehicle is in standby mode and a user connects the electric vehicle to a charging device, the total voltage across the electric vehicle's energy storage battery may fluctuate in a pulsed manner. S301: In the standby mode, determining whether current jamming occurs based on the battery voltage and battery current may include: in the standby mode, detecting whether the battery voltage of the electric vehicle fluctuates in a pulsed manner. When the battery voltage fluctuates in a pulsed manner, determining whether the battery current fluctuates with the battery voltage. If the battery current fluctuates with the battery voltage, current jamming is determined to have occurred. If the battery current does not fluctuate with the battery voltage, current jamming is determined to have not occurred. Preferably, when the battery voltage fluctuates in a pulsed manner, a second expected current range is determined based on the battery voltages before and after the change and the battery current before the change. If the change in battery current reaches the second expected current range, it is determined that the battery current has fluctuated with the battery voltage. If the change in battery current does not reach the second expected current range, it is determined that the battery current has not fluctuated with the battery voltage, and further, current jamming is determined to have occurred. The relationship between the battery voltages before and after the change, the battery current before the change, and the battery current after the change can be measured experimentally, and this relationship can be used to determine the second expected current range.

[0080] S302: Enter different operating modes of the electric vehicle according to at least one state parameter.

[0081] The operating modes include driving mode and charging mode.

[0082] Specifically, the state parameters of the electric vehicle include gear state, battery voltage, vehicle speed and accelerator pedal opening. For example, when it is detected that the vehicle speed is not equal to 0 or the gear state is not neutral, it can be determined that the electric vehicle has entered the driving mode. When it is detected that the battery voltage increases to a preset voltage value (the preset voltage value can be equal to the charging voltage provided by the charging pile), it can be determined that the electric vehicle has entered the charging mode. If the driving mode or charging mode has not been entered, it can be returned to step S301 to repeat the judgment of whether the electric vehicle has current stagnation in the standby state ( Figure 3 Only the case of entering driving mode or charging mode from standby mode is shown).

[0083] S303: In the charging mode, determine whether current jam occurs based on the battery voltage and battery current.

[0084] Specifically, similar to the standby mode, in charging mode, the battery voltage and battery current need to be obtained. If the battery voltage undergoes a pulse change, a determination is made as to whether the battery current varies with the battery voltage. A pulse change refers to an excessively large voltage change within a short period of time. For example, a pulse change may be when the battery voltage changes by more than a preset voltage value within a preset time period. The preset time period may be 1 second, and the preset voltage value may be 10V. If the battery current varies with the battery voltage, then the battery current is not stuck. If the battery current does not vary with the battery voltage, then the battery current is stuck.

[0085] For example, when an electric vehicle is in charging mode, if a user disconnects the electric vehicle from the charging device, the total voltage across the electric vehicle's energy storage battery may pulse. S303. In charging mode, determining whether current jamming occurs based on the battery voltage and battery current may include: S3031. In charging mode, detecting whether the battery voltage of the electric vehicle undergoes pulse jams. S3032. When the battery voltage undergoes pulse jams, determining whether the battery current varies with the battery voltage. S3033. If the battery current does not vary with the battery voltage, determining that current jamming occurs. S3034. If the battery current varies with the battery voltage, determining that current jamming does not occur. Preferably, when the battery voltage undergoes pulse jams, a second expected current range is determined based on the battery voltages before and after the change and the battery current before the change. If the battery current after the change reaches the second expected current range, determining that the battery current has varied with the battery voltage. If the battery current after the change does not reach the second expected current range, determining that the battery current has not varied with the battery voltage, and further determining that current jamming occurs. The relationship between the battery voltage before and after the change, the battery current before the change, and the battery current after the change can be measured experimentally, so that the relationship can be used to determine the second expected current range.

[0086] S304: In the driving mode, when at least one state parameter changes, determine a first expected current range according to the state parameters before and after the change and the battery current before the change.

[0087] S305: Determine whether current jamming occurs according to the first expected current range and the changed battery current.

[0088] S306: Determine whether the preset period has ended based on the time.

[0089] S307: Determine whether the number of current jams within a single preset cycle has reached a preset number.

[0090] S308: If the number of current jams within a single preset cycle reaches a preset number, it is determined that a jam fault occurs in the electric vehicle.

[0091] S309: If the number of current stuck events within a single preset cycle does not reach the preset number, it is determined that the electric vehicle does not have a stuck fault and the number of current stuck events is reset to zero.

[0092] Among them, steps S304, S305, S306, S307, S308 and S309 have the same contents as steps S101, S102, S103, S104, S105 and S106, respectively, and are not repeated here.

[0093] The present embodiment provides a fault diagnosis method for electric vehicle current jam, which determines whether current jam occurs based on whether the battery current changes with the pulse change of the battery voltage when the electric vehicle is in a standby state or a charging state, and determines that a jam fault has occurred in the electric vehicle when the current jam reaches a preset number of times within a preset cycle. This method realizes the judgment of a jam fault of an electric vehicle in a standby state or a charging state, can complete fault diagnosis in advance when the electric vehicle is not driving, and can remind the user to conduct troubleshooting to prevent safety problems caused by current jam during driving, thereby improving the safety of the electric vehicle, so that the current jam diagnosis covers all operating modes of the electric vehicle, and improves the coverage of the fault diagnosis.

[0094] Optionally, continue with reference to Figure 3 After determining that the electric vehicle has not experienced a stuck fault and resetting the number of current stuck events to zero at S309 if the number of current stuck events within a single preset cycle has not reached a preset number, the method may further include determining whether the electric vehicle has exited operation. If the electric vehicle has exited operation, the diagnostic method terminates. If the electric vehicle has not exited operation, the method returns to entering a different electric vehicle operation mode based on at least one state parameter.

[0095] Specifically, at the end of each preset cycle, i.e., after determining whether the electric vehicle has experienced a stuck fault or not, it can also be determined whether the electric vehicle has exited operation. The determination criteria may include whether a shutdown signal has been received. The shutdown signal is a signal triggered by reversing the electric vehicle key and can control the entire vehicle control system to stop operation. If a shutdown signal is received, it can be determined that the electric vehicle is about to exit operation. If a shutdown signal is not received, it can be determined that the electric vehicle is still operating normally (standby mode, driving mode, or charging mode). If the electric vehicle has not exited operation, the process returns to step S302, re-enters a different electric vehicle operating mode based on at least one state parameter, and performs a new preset cycle of current stuck counting.

[0096] Optionally, Figure 4 A flow chart of a method for determining a first expected current range in a driving mode provided by an embodiment of the present invention, referring to Figure 4 Based on the above embodiment, in the driving mode, the method for determining the first expected current range according to the state parameters before and after the change and the battery current includes:

[0097] S401: In driving mode, determine whether the vehicle speed has changed.

[0098] S402: When the vehicle speed changes, determine a first change ratio based on the ratio of the vehicle speeds before and after the change.

[0099] Specifically, in driving mode, when a vehicle speed change is determined, the vehicle speeds before and after the change can be compared to obtain a first change ratio. The first change ratio can indicate the degree of change in the vehicle speed. For example, if the vehicle speed before the change is 50 km / h and the vehicle speed after the change is 60 km / h, the first change ratio can be 5 / 6.

[0100] S403: Determine a first expected current range according to the first change ratio and the battery current before the change.

[0101] Specifically, the first change ratio is related to the degree of change in the battery current. Therefore, the first expected current range can be calculated based on the first change ratio and the battery current before the speed change. For example, if the battery current before the speed change was 6A, and the first change ratio of the speed is 5 / 6, and other state parameters remain unchanged, 6A can be multiplied by 5 / 6 to obtain 5A. 5A is within the first expected current range, and the first expected current range can be determined to be 4.8A-5.2A based on experimental results or empirical values.

[0102] S404: In the driving mode, determine whether the opening of the accelerator pedal changes.

[0103] Specifically, in driving mode, the battery current normally changes with the accelerator pedal opening, so it is possible to determine whether current stagnation occurs when the accelerator pedal opening changes.

[0104] S405 . When the opening changes, determine a second change ratio according to the ratio of the openings before and after the change.

[0105] Specifically, in driving mode, when it is determined that the accelerator pedal opening has changed, the openings before and after the change can be compared to obtain a second change ratio. The second change ratio can represent the degree of change in the accelerator pedal opening. For example, if the accelerator pedal opening before the change is 50% (the depression depth is 50% of the total depression depth) and the accelerator pedal opening after the change is 65%, the second change ratio can be 10 / 13.

[0106] S406: Determine a first expected current range according to the second change ratio and the battery current before the change.

[0107] Specifically, the second change ratio is related to the degree of change in the battery current. Therefore, the first expected current range can be calculated based on the second change ratio and the battery current before the accelerator pedal depth change. For example, if the battery current before the accelerator pedal opening changes is 6A, and the second change ratio of the accelerator pedal opening is 6 / 5, and other state parameters remain unchanged, 6A can be divided by 6 / 5 to obtain 5A. 5A is within the first expected current range. Based on experimental results or empirical values, the first expected current range can be determined to be 4.8A-5.2A.

[0108] The present embodiment provides a fault diagnosis method for electric vehicle current jam. In driving mode, a first expected current range is determined based on the ratio of the vehicle speed and the accelerator pedal opening, as well as the battery current before the change. Whether current jam has occurred is then determined based on the relationship between the actual battery current after the change and the first expected current range. This enables the judgment of electric vehicle current jam during driving, and further completes the jam fault determination. This method uses less data and does not require recording a large amount of historical data for comparison, thereby improving the simplicity of the fault diagnosis method.

[0109] Optionally, Figure 5 A flow chart of a method for determining a first expected current range in a standby state or charging mode provided by an embodiment of the present invention, with reference to Figure 5 Based on the above embodiment, in the standby state or charging mode, when the battery voltage undergoes a pulse change, determining the second expected current range based on the battery voltage before and after the change and the battery current before the change includes:

[0110] S501: In a standby state or a charging mode, determine whether a pulse change occurs in the battery voltage.

[0111] Specifically, in standby mode or charging mode, the battery current normally changes with the pulse change of the battery voltage. Therefore, it is possible to determine whether current stagnation occurs when the battery voltage pulses.

[0112] S502: When a pulse change occurs in the battery voltage, determine a third change ratio according to a ratio of the battery voltage before and after the change.

[0113] Specifically, in standby mode or charging mode, when it is determined that a pulse change has occurred in the battery voltage, the battery voltage before and after the change can be compared to obtain a third change ratio. The third change ratio can represent the degree of change in the battery voltage. For example, if the battery voltage before the change is 200V and the battery voltage after the change is 380V, the third change ratio can be 10 / 19.

[0114] S503: Determine a second expected current range according to the third change ratio and the battery current before the change.

[0115] Specifically, the third change ratio is related to the degree of change in the battery current, so the second expected current range can be calculated based on the third change ratio and the battery current before the battery voltage changes. For example, if the battery current before the battery voltage pulse changes is 10A, and the third change ratio of the battery voltage is 10 / 19, when other state parameters remain unchanged, 10A can be divided by 10 / 19 to obtain 19A. 19A is within the second expected current range, and 18A-20A can be determined as the second expected current range based on experimental results or empirical values. In addition, the vehicle control system can also directly determine the second expected current range based on the type of charging pile connected. For example, when the charging pile is a constant current charging pile, the second expected current range can be the charging current range of the constant current charging pile.

[0116] The electric vehicle current stuck fault diagnosis method provided in this embodiment can diagnose electric vehicle stuck faults using corresponding state parameters in different modes or states. In driving mode, current stuck is determined in response to changes in vehicle speed or accelerator pedal opening. A first expected current range is determined based on the vehicle speed or accelerator pedal opening before and after the change and the battery current before the change. Current stuck is then determined based on the first expected current range and the battery current after the change. In standby or charging mode, current stuck is determined in response to changes in battery voltage pulses. A second expected current range is determined based on the battery voltage before and after the change and the battery current before the change. Current stuck is then determined based on the second expected current range and the battery current after the change. This method enables current stuck detection and counting in various modes and states, improving the accuracy of fault diagnosis and comprehensively enhancing the safety of electric vehicles.

[0117] An embodiment of the present invention further provides a fault diagnosis device for electric vehicle current stagnation. Figure 6 A schematic diagram of a fault diagnosis device for electric vehicle current jamming provided by an embodiment of the present invention, referring to Figure 6 The electric vehicle current stuck fault diagnosis device 600 includes: a first expected current range determination unit 601, a current stuck determination unit 602, and a stuck fault judgment unit 603. The first expected current range determination unit 601 is configured to, in driving mode, determine a first expected current range based on the state parameters before and after the change and the battery current before the change when at least one state parameter changes. The state parameter includes at least one of battery voltage, vehicle speed, and accelerator pedal opening. The current stuck determination unit 602 is configured to determine whether current stuck occurs based on the first expected current range and the changed battery current. The stuck fault judgment unit 603 is configured to determine that the electric vehicle has a stuck fault if the number of current stuck events within a single preset cycle reaches a preset number, and to determine that the electric vehicle has not suffered a stuck fault and reset the number of current stuck events to zero if the number of current stuck events within a single preset cycle does not reach the preset number.

[0118] Optionally, based on the aforementioned embodiment, the electric vehicle current stuck fault diagnosis device further includes: a mode determination module configured to enter different operating modes of the electric vehicle based on at least one state parameter, wherein the operating modes include driving mode and charging mode. The current stuck determination unit is further configured to determine whether current stuck occurs based on the battery voltage and battery current in the standby mode, and to determine whether current stuck occurs based on the battery voltage and battery current in the charging mode.

[0119] The present embodiment provides a method and device for diagnosing electric vehicle current stuck faults. During driving, if a state parameter changes, a first expected current range is determined based on the state parameters before and after the change and the battery current before the change. Current stuck is then determined based on the first expected current range and the battery current after the change. If the number of current stuck events in a single preset cycle reaches a preset number, the electric vehicle is determined to have a stuck fault. If the number of current stuck events in a single preset cycle does not reach the preset number, the electric vehicle is determined not to have a stuck fault within the preset cycle and the number of current stuck events is reset to zero. This facilitates the diagnosis of electric vehicle stuck faults. Each current stuck fault determination in this process is based solely on the state parameters before and after a single change and the battery current, eliminating the need for extensive historical data comparison and reducing data requirements. Each current stuck fault determination is performed when the state parameter changes, eliminating the need to reach a certain speed and requiring a low threshold for triggering the determination. The preset period and number of current stuck faults employed in the stuck fault diagnosis process reduce false stuck alarms caused by sensor signal errors, thereby improving the accuracy of fault diagnosis. The aforementioned product can implement the method provided by any embodiment of the present invention and possesses the corresponding functional modules and beneficial effects of the method. Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations, and substitutions are possible for those skilled in the art without departing from the scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A fault diagnosis method for electric vehicle current stagnation, characterized in that: include: Entering different operating modes of the electric vehicle according to at least one state parameter, wherein the operating modes include a driving mode and a charging mode, and the state parameter includes at least one of a battery voltage, a vehicle speed, and an accelerator pedal opening; In the charging mode, determining whether current jam occurs based on the battery voltage and the battery current specifically includes detecting the battery voltage and the battery current; when the battery voltage undergoes a pulse change, determining whether the battery current changes with the battery voltage; and determining that current jam occurs if the battery current does not change with the battery voltage; In the driving mode, when at least one state parameter of the electric vehicle changes, a first expected current range is determined according to the state parameters before and after the change and the battery current before the change; determining whether current jamming occurs according to the first expected current range and the changed battery current; If the number of times the current is stuck reaches a preset number within a single preset cycle, it is determined that a stuck fault occurs in the electric vehicle; If the number of current jams within a single preset cycle does not reach a preset number, it is determined that no jam fault occurs in the electric vehicle and the number of current jams is reset to zero.

2. The electric vehicle current stuck fault diagnosis method according to claim 1, characterized in that: Before entering different operation modes of the electric vehicle according to at least one state parameter, the method further includes: In the standby state, whether current jamming occurs is determined based on the battery voltage and the battery current.

3. The fault diagnosis method for electric vehicle current stagnation according to claim 1, characterized in that: When the battery voltage undergoes a pulse change, determining whether the battery current changes with the battery voltage includes: When a change in the battery voltage within a preset period exceeds a preset voltage value, determining a second expected current range according to the battery voltage before and after the change and the battery current before the change; If the changed battery current reaches the second expected current range, determining that the battery current changes with the battery voltage; If the changed battery current does not reach the second expected current range, it is determined that the battery current does not change with the battery voltage.

4. The electric vehicle current stuck fault diagnosis method according to claim 1, characterized in that: After determining that the electric vehicle has a stuck fault and determining that the electric vehicle has not a stuck fault, the method further includes: Determining whether the electric vehicle has exited operation; If the electric vehicle is out of operation, then the diagnostic method ends; If the electric vehicle has not exited operation, the operation mode of the electric vehicle is returned to a different operation mode according to at least one of the state parameters.

5. The fault diagnosis method for electric vehicle current stagnation according to claim 1, characterized in that: When at least one state parameter of the electric vehicle changes in a driving mode, determining a first expected current range based on the state parameters before and after the change and the battery current includes: When the vehicle speed changes, determining a first change ratio according to a ratio of the vehicle speeds before and after the change; The first expected current range is determined according to the first change ratio and the battery current before the change.

6. The electric vehicle current stuck fault diagnosis method according to claim 1, characterized in that: When at least one state parameter of the electric vehicle changes in a driving mode, determining a first expected current range based on the state parameters before and after the change and the battery current includes: When the opening of the accelerator pedal changes, determining a second change ratio according to a ratio of the openings of the accelerator pedal before and after the change; The first expected current range is determined according to the second change ratio and the battery current before the change.

7. The electric vehicle current stuck fault diagnosis method according to claim 3, characterized in that: When the battery voltage undergoes a pulse change, determining a second expected current range according to the battery voltage before and after the change and the battery current before the change includes: When the battery voltage undergoes a pulse change, determining a third change ratio according to a ratio of the battery voltage before and after the change; The second expected current range is determined according to the third change ratio and the battery current before the change.

8. A fault diagnosis device for electric vehicle current stagnation, characterized in that: include: a first expected current range determining unit, configured to determine the first expected current range according to the state parameters before and after the change and the battery current before the change when at least one state parameter of the electric vehicle changes in the driving mode, wherein the state parameters include the battery voltage, the vehicle speed, and the opening of the accelerator pedal; a current jam determining unit, configured to determine whether current jam occurs according to the first expected current range and the changed battery current; a stuck fault judgment unit, configured to determine that a stuck fault has occurred in the electric vehicle if the number of times the current is stuck reaches a preset number within a single preset cycle, and to determine that no stuck fault has occurred in the electric vehicle and reset the number of current stuck times to zero if the number of times the current is stuck does not reach the preset number within a single preset cycle; The current jam determination unit is further configured to enter different operating modes of the electric vehicle based on at least one state parameter, wherein the operating modes include a driving mode and a charging mode, and the state parameter includes at least one of a battery voltage, a vehicle speed, and an accelerator pedal opening; in the charging mode, determining whether the current jam occurs based on the battery voltage and the battery current, specifically comprising detecting the battery voltage and the battery current; when the battery voltage undergoes a pulse change, determining whether the battery current changes with the battery voltage; and determining that current jam occurs if the battery current does not change with the battery voltage.

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