Electric automobile alternating current charging protection method and automobile

Abstract

The invention discloses an electric automobile alternating current charging protection method and an automobile. The method comprises the steps that in the charging process, a BMS detects a CP signal value through a whole automobile OBC, abnormal fluctuation monitoring is conducted on the detected CP signal value, and ending control is conducted on the charging process according to abnormal fluctuation of the CP signal obtained through monitoring. The method has the advantages that when the electric vehicle is slowly charged and encounters an external fault, the fault can be accurately recognized, charging can be forbidden, the safety of the high-voltage relay and the vehicle is protected, and the implementation method is simple. The charging process is dynamically monitored through identification of CC and CP signals, then the charging fault state is identified, the charging process is timely disconnected or recovered according to the fault state, the charging protection work is completed under the condition that the charging requirement of a user is met as much as possible, and the charging safety and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicle charging protection, and particularly to an AC charging control and protection method for electric vehicles and an electric vehicle. Background Art

[0002] With the shortage of petroleum energy and the aggravation of urban air pollution, more and more electric vehicles are accepted by the general public. As the "gas station" for electric vehicles, charging piles are also widely popularized with the application of electric vehicles.

[0003] The function of a charging pile is similar to that of a fuel dispenser in a gas station. It can be fixed on the ground or wall, installed in public buildings, residential community parking lots or charging stations, and can charge various models of electric vehicles according to different voltage levels. Slow charging means that the alternating current from the power grid is input into the slow charging port of the electric vehicle, and after the on-board charger inside the vehicle converts the alternating current into direct current, it is then input into the battery to complete the charging. The charging interface used is an AC charging pile interface.

[0004] Most of the slow charging pile products and electric vehicle products on the market are provided by different companies respectively, which means that the data generated during the charging process of the charging pile and the vehicle battery belong to different companies, and the data between the two is not interconnected and interactive. Currently, the conventional charging scheme between the charging pile and the vehicle battery is that the on-board charger (OBC) of the vehicle detects two hard wire signals, CC / CP, to determine whether the charging pile is fully connected. The OBC closes the S2 switch to tell the charging pile that the vehicle is ready for charging. During the charging process, the charging pile continuously outputs the CP duty cycle to ensure the normal output of the electric energy of the charging pile; when the vehicle OBC detects that the CC or CP signal is abnormal, the charging stops. When the user encounters a faulty slow charging pile during slow charging at night or when there is a power supply fault or abnormality in the power grid, it will cause the CP value detected by the OBC module to keep jumping back and forth repeatedly, which will cause the vehicle to be in a charge-no charge state and may keep cycling. In addition, considering that slow charging conditions generally occur at night and there is no user supervision, the main positive, main negative, and pre-charge relays in the vehicle battery pack will always be in a state of connecting, disconnecting, and reconnecting, and there is a risk of relay adhesion. For this technical problem, no effective solution has been proposed yet. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an AC charging protection method for electric vehicles and an electric vehicle, which can accurately identify faults and prohibit charging when external faults occur during slow charging of electric vehicles, protect the high-voltage relay and vehicle safety, and the implementation method is simple.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: An AC charging protection method for an electric vehicle, during the charging process, the BMS detects the CP signal value through the vehicle OBC, monitors the abnormal fluctuations of the detected CP signal value, and controls the end of the charging process according to the abnormal fluctuations of the CP signal obtained by the monitoring.

[0007] During the charging process, when it is monitored that the duty cycle of the CP signal changes suddenly and the CC signal remains valid all the time, the BMS controls the end of the charging process and monitors the CP signal value in real time. When the CP signal value returns to normal, at this time, the BMS controls the charging process to start and continue charging, and at the same time, the value of the number of charging abnormal fluctuations recorded in the BMS is incremented by one.

[0008] The BMS determines whether to end the charging according to the number of charging abnormal fluctuations recorded during this charging process. When the number of charging abnormal fluctuations is greater than the set number threshold, the BMS issues a charging end request, and at this time, the charging process is controlled to end.

[0009] After the charging process ends, the CC signal is monitored in real time. Only when it is detected that the CC signal is first disconnected and then reconnected, the BMS resumes the charging process and controls the start of charging according to the CC and CP signals.

[0010] When the number of charging abnormal fluctuations is greater than the set number threshold, calculate the time spent from the first abnormal fluctuation to the set threshold number of fluctuations. Only when the time is less than the set time threshold, it is judged to end the charging process, and the BMS issues a charging end request.

[0011] Monitor the CP signal value. When the change in the duty cycle of the CP signal exceeds the normal duty cycle and reaches the set range, it is judged that the CP signal fluctuates abnormally.

[0012] After the BMS issues a charging end request, a notice of abnormal charging end is sent to the user through the vehicle network.

[0013] During the charging process, monitor the fluctuation state of the CC signal through the BMS. When it is detected that either the CC or CP signal fluctuates, identify the state of the charging gun through the vehicle-mounted sensor. When it is judged that the fluctuation of the CC or CP signal is caused by the vibration of the charging gun at this time, the BMS requests the end of charging, and at the same time monitors the vibration of the charging gun. After the vibration of the charging gun ends, the BMS controls the start of the charging process, and judges whether the CC and CP signals are restored. If restored, the BMS issues a charging request, otherwise, keep the charging state disconnected.

[0014] When the charging gun vibrates, control the vehicle-mounted camera to start video acquisition of the position of the charging gun, and use the image recognition algorithm to identify the people around the charging gun. When people are identified, a voice reminder signal to drive them away is sent through the vehicle-mounted voice.

[0015] A car, and the AC charging protection method when the car is being charged.

[0016] The advantages of the present invention are that when an electric vehicle encounters an external fault during slow charging, it can accurately identify the fault and prohibit charging, protect the high-voltage relay and the vehicle safety, and the implementation method is simple. By identifying the CC and CP signals, the charging process is dynamically monitored and the charging fault state is identified. The charging process is disconnected or restored in time according to the fault state, and the charging protection work is completed while meeting the user's charging needs as much as possible, thereby improving the safety and reliability of charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0018] Figure 1 It is a schematic diagram of the flow of the charging protection method of the present invention. DETAILED DESCRIPTION

[0019] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0020] The purpose of the present invention is to provide an AC charging protection strategy for electric vehicles to overcome the problems existing in the prior art. The present invention can prohibit charging when an external fault occurs during slow charging of the electric vehicle, protect the high-voltage relay and the vehicle safety, and the implementation method is simple. To achieve the above purpose, the present invention adopts the following technical solutions:

[0021] At present, the conventional charging scheme between the charging pile and the vehicle battery is to use the vehicle's OBC module to detect the two hard-wired signals CC / CP at the pile end to determine whether the charging pile is fully connected. The OBC tells the charging pile that the vehicle is ready to charge by closing the S2 switch. During the charging process, the charging pile continuously outputs the CP duty cycle to ensure the normal output of the charging pile's power; when the vehicle's OBC detects an abnormality in the CC or CP signal, charging stops. When the user encounters a faulty slow charging pile or a power grid failure, the CP value detected by the vehicle's OBC may repeatedly change from valid to invalid, which will cause the vehicle to be in a state of repeated charging-stop charging. In addition, considering that slow charging conditions are generally more common at night and there is no user supervision, the vehicle's high-voltage relay is closed and disconnected countless times throughout the night, and there is a risk of relay adhesion.

[0022] The present invention detects the CP signal sent by the vehicle OBC during slow charging through the BMS. For example, during slow charging, if the BMS detects that the duty cycle of CP suddenly fluctuates abnormally and CC remains connected, such as when the duty cycle of CP mutates multiple times and CC always remains connected, when it reaches the fifth time, the BMS charging status sends a charging end. If it is necessary to enter the next charging cycle, the CC signal needs to be manually disconnected. By detecting the CP signal sent by the vehicle OBC during slow charging, for example, during slow charging, if the BMS detects that the duty cycle of CP suddenly changes and CC remains connected, such as when the duty cycle of CP mutates multiple times and CC always remains connected, when it reaches the fifth time, the BMS charging status sends a charging end. If it is necessary to enter the next charging cycle, the CC signal needs to be manually disconnected. This method can avoid the reverse charging power-off caused by grid-side or charging-pile-side faults during charging, the charging safety hazards caused by repeated cycles, and the adhesion of relay contacts.

[0023] As Figure 1 shown, first, normally enter AC charging. After inserting the charging gun into the vehicle-mounted charging port, the vehicle-mounted charging program starts to interact to complete AC charging. Enter AC charging and start charging.

[0024] After entering charging, the vehicle OBC module receives the control of the BMS to detect the current CC and CP values. The BMS judges the CC and CP signal values of the detected charging gun. When the detected CC and CP signal values are normal, continue to monitor and judge the CC and CP values through the OBC.

[0025] If there is a problem with the CP low-voltage signal line at the pile end or the power supply at the pile end, resulting in an abnormal change in the CP value and the charging gun remains connected (the CC value is normal), when the BMS detects an abnormal change in the CP value and CC remains unchanged, the BMS stops charging and records it as 1 time; then, it continuously monitors in real time whether the power supply fault / low-voltage harness fault at the pile end is restored and the CP value returns to normal; when the BMS detects that CC remains unchanged and CP returns to the normal value, it resumes the charging request.

[0026] After the resume charging request, continue to monitor the CC and CP values through the OBC. When there is a problem with the CP low-voltage signal line at the pile end or the power supply at the pile end, resulting in abnormal changes in the CP value and the charging gun remains connected; when the BMS detects abnormal changes in the CP value and the CC remains unchanged, the BMS stops charging and records it twice; when the power supply fault / low-voltage harness fault at the pile end is restored and the CP value returns to normal; when the BMS detects that the CC remains unchanged and the CP returns to the normal value, the resume charging request is restored, and the above operations are repeated to monitor the CP and CC values. During a single AC charging process (the CC connection is not disconnected), the BMS can restore the charging request after the CP value has been abnormally restored 5 times. If the 6th CP value abnormality occurs, the charging stop record event flag bit is set, and the clearing condition is to disconnect the CC connection. When there are more than 5 abnormal fluctuations, it is judged that there is a fault on the charging side at this time, which causes the charging to be repeatedly disconnected, easily leading to charging faults and even relay contact adhesion. Therefore, at this time, the fault is judged, and the BMS directly requests to end the charging, and the charging cannot be restored after the end of the charging. In the connection state of the CC signal feedback in this time, that is, when the charging gun is continuously connected, recharging is not allowed. Only when the CC signal is disconnected and then reconnected is it allowed to resume the charging process, thus realizing reliable protection of charging and avoiding relay adhesion caused by repeated disconnection of charging.

[0027] In this embodiment, it mainly utilizes the interaction of the CC and CP signal values between the charging gun and the vehicle after the charging gun is inserted into the charging port. By collecting the status of the CC and CP signal values, it is judged whether there are abnormal fluctuations in the vehicle's charging and whether the plug connection of the charging gun is normal, and then it is judged whether to perform charging protection. In a method for protecting AC charging of an electric vehicle in this application, during the charging process, the BMS detects the CP signal value through the vehicle OBC, monitors the abnormal fluctuations of the detected CP signal value, and controls the end of the charging process according to the abnormal fluctuations of the CP signal obtained by the monitoring. During the charging process, the vehicle OBC module will monitor the CC and CP signal values. Under normal circumstances, the CC value will remain constant during the charging process, which means that the charging gun has been connected to the charging port all the time. The CP value will remain unchanged or change slowly according to the charging strategy but will not mutate or fluctuate greatly. Therefore, the current charging state can be judged according to the characteristics of the CC value and the CP value, and then the charging protection control can be realized.

[0028] During the charging process, when it is monitored that the duty cycle of the CP signal changes suddenly and the CC signal remains valid all the time, the BMS controls the end of the charging process and monitors the CP signal value in real time. When the CP signal value returns to normal, the BMS then controls the start of the charging process to continue charging, and at the same time, the value of the number of abnormal charging fluctuations recorded in the BMS is incremented by one. A variable count is set in the BMS. The variable count is used to record the abnormal charging fluctuation value during this charging process. After the vehicle OBC module first detects the CC value, the variable count is initialized to 0 at this time; after the BMS starts the charging program, the vehicle starts charging, and the BMS monitors the CC value and the CP value; when it is monitored that the CC value remains unchanged all the time (i.e., the charging gun remains normally connected) and an abnormal fluctuation of the CP value is detected, the BMS will then control the count to increment by one; then the BMS will control the charging to pause according to the abnormal fluctuation of the CP value, and resume charging after the CP value is restored and the CC value remains in the connected state.

[0029] During a charging process, as long as the CC remains connected, it is regarded as one charging process. During one charging process, the CP fluctuation value each time is monitored. Each time there is a fluctuation, the abnormal fluctuation of the CP value during one charging process is counted by incrementing count by one. When the count is greater than 5, that is, when the count value is equal to 6, the BMS directly issues a request to end the charging, and the charging is ended through interaction with the charging pile. At this time, ending the charging instead of pausing the charging is adopted to avoid the charging safety hazards caused by the repeated fluctuations of the CP value during one charging. Repeated fluctuations of the CP value during one charging process indicate that there is an abnormality in the charging pile or the power grid on the power supply side. At this time, it is necessary to end the charging to avoid the safety hazards brought by abnormal charging and the impact on the vehicle's relay.

[0030] For the judgment of the abnormal fluctuation of the CP value, in this embodiment, the duty cycle of the CP signal is used for judgment. When the duty cycle of the CP signal fluctuates greatly, it is judged that the CP signal has an abnormal fluctuation. The abnormal fluctuation can be judged according to the fluctuation magnitude or the fluctuation percentage of the duty cycle, thus realizing the judgment of the abnormal fluctuation of the CP signal. The CP signal value is monitored. When the change of the CP signal duty cycle exceeds the normal duty cycle and reaches the set range, it is judged that the CP signal fluctuates abnormally.

[0031] In a preferred solution of this embodiment, when the number of abnormal charging fluctuations is greater than the set number threshold, calculate the time spent from the first abnormal fluctuation to the fluctuation between the set number threshold fluctuations. Only when the time is less than the set time threshold, it is determined to end the charging process, and the BMS sends a charging end request. The BMS determines whether to end the charging based on the number of charging abnormal fluctuations recorded during this charging process. When the number of charging abnormal fluctuations is greater than the set number threshold, the BMS sends a charging end request, and at this time, the charging process is controlled to end. During a charging process, the time may be very long. To more accurately identify and end the charging process, not only the count value is judged, but also the time spent from counting the count value from 1 to 6, that is, when the number of abnormal fluctuations reaches 6 times and the time spent between the first abnormal fluctuation and the sixth abnormal fluctuation is less than the time threshold, then at this time, the BMS issues an instruction to end the charging request, so as to end the charging more accurately. Because in this solution, a charging process is judged according to the CC signal value to maintain the connection. If the CC remains unchanged all the time and the time is stretched very long, then the time between CP fluctuations is also very long, and accurate judgment cannot be achieved. This solution not only judges the count value but also adds a judgment on the time spent between the count value taking values from 1 to 6. It is required that the time is relatively short to judge the faults on the grid or charging pile side. When the spent time is less than the set time threshold, the BMS judges to end this charging process, and the BMS sends a charging end request, and ends this charging through the interaction with the charging pile.

[0032] After the charging process ends, the CC signal is monitored in real time. Only when it is detected that the CC signal is first disconnected and then reconnected, the BMS resumes the charging process and controls the charging to start according to the CC and CP signals. Because after the BMS requests to end the charging, charging cannot be resumed this time until it is monitored that the CC signal value is first disconnected and then restored. Because the CC value represents whether the charging gun is disconnected or not, only when it is detected according to the CC value that the charging gun is disconnected and then restored is charging allowed to be resumed. This can meet the requirement that after a charging ends, the user manually resumes the charging process.

[0033] In order to timely remind the user of the current charging status, when the vehicle charging ends due to an abnormality, the user needs to be notified to remind the user to handle it in time to avoid user experience problems caused by the user not knowing that the charging has ended. To implement the alarm notification, after the BMS sends a charging end request, a notification of abnormal charging end is sent to the user through the vehicle network. Through the vehicle network, a corresponding charging protection reminder is sent to the vehicle user's mobile phone APP via the TBOX, so as to effectively remind the user.

[0034] In a preferred embodiment of this solution, during the charging process, the BMS monitors the fluctuation state of the CC signal. When any fluctuation of the CC or CP signal is detected, the in-vehicle sensor is used to identify the state of the charging gun. When it is determined that the CC or CP signal fluctuation is caused by the vibration of the charging gun at this time, the BMS requests the charging to end and simultaneously monitors the vibration of the charging gun. After the vibration of the charging gun ends, the BMS controls the start of the charging process and determines whether the CC and CP signals are restored. If they are restored, the BMS issues a charging request; otherwise, the charging state remains disconnected. Since the abnormal fluctuation of the CP signal may be caused by a fault on the charging pile side or by the illegal unplugging of the charging gun by a person, and similarly, the abnormal fluctuation of the CC signal may also be the signal fluctuation caused by the illegal unplugging by a person. Therefore, when any abnormal fluctuation of the CC or CP signal is detected, it is necessary to determine whether there is a human-generated unplugging phenomenon at this time. To detect this phenomenon, the in-vehicle panoramic camera is used to collect the video image at the charging gun, identify the position of the charging gun, compare the position of the charging gun between the previous two frames of images, and determine whether the charging gun vibrates based on the fluctuation of the charging gun position in the front and rear two frames of images. When it is determined to be a fluctuation, to avoid the charging risk brought by this charging fluctuation, the charging is first disconnected, and then the vibration signal is monitored. When it is monitored that the vibration of the charging gun ends, the charging process is started again, and it is determined whether the CC and CP signals are restored. Because if the vibration is caused by a human factor, if the CC signal is still detected after the vibration ends and the vibration ends, it means that the interference factor of the human plugging and unplugging ends. At this time, an attempt is made to resume charging, and the CC and CP signal values are collected to determine whether to continue charging and control the charging process according to the CC and CP signal values.

[0035] In this application, when the charging gun vibrates, the in-vehicle camera is controlled to start video collection of the position of the charging gun, and the image recognition algorithm is used to identify the people around the charging gun. When people are recognized, a voice reminder signal to drive them away is sent through the in-vehicle voice. The voice signal can emit an alarm sound through the in-vehicle voice, in-vehicle speaker, etc. to drive away the people around the charging gun, avoid or reduce the charging safety problems caused by the illegal unplugging of the charging gun, give an alarm and drive away in time, and after the CC and CP signals return to normal after driving away, resume the charging process, reduce the charging safety hazards caused by external human interference, and resume the charging process after the safety hazards end to ensure the charging needs of users.

[0036] In the charging protection method of this embodiment, this charging protection method is applied to an automobile. The automobile has a charging safety protection function, which can effectively avoid the repeated charging and power-off of the automobile caused by a power supply side fault during charging, and thus avoid problems such as the adhesion of relay contacts caused by repeated power-on and power-off, improving the charging safety.

[0037] Obviously, the specific implementation of the present invention is not limited by the above-mentioned manner. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. An electric vehicle AC charging protection method, characterized in that: During the charging process, the BMS detects the CP signal value through the vehicle OBC, monitors the abnormal fluctuation of the detected CP signal value, and controls the end of the charging process according to the abnormal fluctuation of the monitored CP signal.

2. An electric vehicle AC charging protection method as claimed in claim 1, characterized in that: During the charging process, when the CP signal duty cycle is monitored to change suddenly and the CC signal remains valid, the BMS controls the charging process to end and monitors the CP signal value in real time. When the CP signal value returns to normal, the BMS controls the charging process to start and continue charging. At the same time, the number of abnormal charging fluctuations recorded in the BMS is increased by one.

3. An electric vehicle AC charging protection method as claimed in claim 2, characterized in that: The BMS determines whether to end charging based on the number of abnormal charging fluctuations recorded during this charging process. When the number of abnormal charging fluctuations is greater than the set threshold, the BMS issues a charging end request, and the charging process is controlled to end.

4. An AC charging protection method for electric vehicles as claimed in claim 3, characterized in that: After the charging process is completed, the CC signal is monitored in real time. Only when it is detected that the CC signal is disconnected and then connected, the BMS resumes the charging process and controls the charging to start according to the CC and CP signals.

5. An electric vehicle AC charging protection method as claimed in claim 3, characterized in that: When the number of abnormal charging fluctuations is greater than the set threshold, the time taken from the first abnormal fluctuation to the set threshold fluctuation is calculated. Only when the time is less than the set time threshold is the charging process judged to be terminated, and the BMS issues a charging end request.

6. An electric vehicle AC charging protection method according to any one of claims 1 to 5, characterized in that: The CP signal value is monitored, and when the CP signal duty cycle changes beyond the normal duty cycle and reaches the set range, it is determined that the CP signal fluctuation is abnormal.

7. An electric vehicle AC charging protection method according to any one of claims 1 to 5, characterized in that: After the BMS issues a request to end charging, a notification of abnormal charging end is sent to the user through the Internet of Vehicles.

8. An electric vehicle AC charging protection method according to any one of claims 1 to 5, characterized in that: During the charging process, the BMS monitors the CC signal fluctuation status. When any fluctuation of the CC or CP signal is detected, the status of the charging gun is identified by the on-board sensor. When it is determined that the CC or CP signal fluctuation is caused by the vibration of the charging gun, the BMS requests the end of charging and monitors the vibration of the charging gun at the same time. When the vibration of the charging gun ends, the BMS controls the start of the charging process to determine whether the CC and CP signals are restored. If restored, the BMS issues a charging request, otherwise the charging state remains disconnected.

9. An electric vehicle AC charging protection method as claimed in claim 8, characterized in that: When the charging gun vibrates, the on-board camera is controlled to start video acquisition of the charging gun position, and the image recognition algorithm is used to identify the portraits around the charging gun. When the portrait is recognized, a voice reminder signal to drive away is issued through the on-board voice.

10. An automobile, characterized in that: The automobile adopts the AC charging protection method as described in any one of claims 1-9 when charging.

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