AC slow charging method for electric vehicles

Abstract

The present invention relates to the technical field of charging methods, and in particular to an AC slow charging method for an electric vehicle, comprising the following steps: S1, a wake-up stage; S2, a charging condition determination stage; S3, an AC charging stage; S4, a charging stop and charging dormancy stage; during the AC charging stage, if an irrecoverable fault occurs in an OBC, the method proceeds to S5, an OBC fault processing stage; during step S3, the AC charging stage, if an electronic lock fails or a user presses an electronic lock switch, causing poor contact of the electronic lock switch, the method proceeds to S6, an electronic lock failure or pressing electronic lock processing stage; during step S3, the AC charging stage, if an irreversible fault occurs in a DC / DC or a BMS, the method proceeds to S7, a DC / DC or BMS fault processing stage; in the present invention, a CC / CP is controlled by a BMS, triggering AC charging, and information is exchanged between a VCU, the OBC, and a BCM to complete AC charging.

Description

Technical Field

[0001] The present invention relates to the technical field of charging methods, and in particular to an AC slow charging method for an electric vehicle. Background Art

[0002] As the number of electric vehicles increases every year, every electric vehicle may use AC slow charging. AC charging safety is particularly important at this time. How to provide a safe AC slow charging method for electric vehicles is a problem that needs to be solved. Summary of the Invention

[0003] The main purpose of the present invention is to provide an AC slow charging method for electric vehicles to solve the problem of how to provide a safe AC slow charging method for electric vehicles in the above-mentioned prior art.

[0004] In order to achieve the above object, the present invention provides an AC slow charging method for an electric vehicle, characterized in that it includes the following steps:

[0005] S1, awakening stage

[0006] S1a, the user inserts the charging gun and wakes up the BMS through CC / CP;

[0007] S1b, after successfully waking up the BMS, the BMS initializes self-test. After the self-test is completed, the VCU is awakened through CAN information. If the BMS fails to wake up, it determines whether the wake-up signal is valid. If the wake-up signal is valid, the BMS performs initialization self-test. If the wake-up signal is invalid, the BMS enters the sleep stage.

[0008] S1c, VCU performs initialization self-test. After the self-test is completed, it sends a wake-up signal to BMS and OBC through network management or output hard line. If the initialization self-test is not completed, the initialization self-test fails.

[0009] S1d, if the BMS receives a valid wake-up signal from the VCU, the BMS receives a constant-level CP signal output by the power supply device, checks the CC / CP status, and uploads the CP status duty cycle, frequency, peak voltage information, CC resistance status, maximum grid current, and maximum cable current to the CAN bus, and sends the CC status and CP status to the OBC. If the BMS receives an invalid wake-up signal from the VCU, it continues to wake up the VCU through CAN information. The OBC receives the wake-up command, initializes the self-test, and after the initialization and self-test are completed, uploads the OBC status and fault information to the VCU. The OBC receives the CC status and CP status provided by the BMS and reports the OBC working status to the OBC.

[0010] S2. Charging condition determination stage

[0011] S2a. If the BMS receives the OBC feedback signal and the PWM type CP signal output by the power supply device and detects the CP duty cycle, it executes the electronic lock closing command, and the electronic lock is closed and fed back to the VCU. If the BMS does not receive the OBC feedback signal and the PWM type CP signal output by the power supply device and detect the CP duty cycle, the BMS enters the sleep state.

[0012] S2b, after receiving the electronic lock closing signal, the VCU sends a signal to prohibit the motor from outputting torque, exits the "READY" state, and sends a high-voltage pre-charge command to the BMS;

[0013] S2c and BMS receive the high-voltage pre-charge command, perform pre-charge, and feedback the pre-charge completion to VCU;

[0014] S2d, VCU receives the pre-charge completion instruction and issues the power battery contactor closing instruction. After receiving the command, BMS closes the power battery contactor, closes the S2 switch, and sends the S2 switch status information to VCU and OBC;

[0015] S2e: If the status information of the S2 switch is valid, the OBC receives the information that the S2 switch is closed, the power supply equipment contactor is closed, and the AC voltage starts to be output, and reports the AC port high-voltage interlock signal, OBC fault status and power supply equipment voltage to the VCU; if the status information of the S2 switch is invalid, the BMS enters the sleep state;

[0016] S3, AC charging stage

[0017] S3a, VCU receives the information reported by OBC, sends the slow charging start instruction to BMS and sends the DC output enable signal to DC / DC converter;

[0018] S3b. If the BMS receives a valid instruction to allow charging, it sends the charging mode, charging voltage, and charging current values ​​to the OBC. If the BMS receives an invalid instruction to allow charging, it enters a dormant state.

[0019] After receiving the charging working mode, S3c and OBC start working, perform charging, and report the charging status to BMS;

[0020] S3d and BMS estimate the remaining charging time and exchange charging information with OBC;

[0021] S3e and BMS determine whether the battery is fully charged. If not, the battery continues to charge. After the battery is fully charged, the BMS sends a full charge feedback to the VCU.

[0022] S4, charging stop and charging sleep stage

[0023] S4a, VCU receives the full charge command from BMS and sends the stop AC charging and clear AC charging instructions to BMS;

[0024] S4b, after receiving the stop charging command, BMS sends a clear charger working mode to OBC;

[0025] S4c, after receiving the clear working mode, OBC stops charging and reports the OBC standby state. If there is no other instruction within the set time, OBC enters the sleep state;

[0026] S4d, BMS receives the OBC standby status, executes the disconnection of S2 switch, and reports the S2 switch information to VCU;

[0027] S4e and VCU receive the S2 switch disconnection information, send a stop DCDC enable output signal to the DC / DC converter, and send a BMS contactor disconnection instruction to the BMS. If there is no other instruction within the set time, the VCU enters the sleep state;

[0028] S4f, after receiving the contactor disconnect command, BMS executes the contactor disconnection. If there is no other instruction within the set time, BMS enters the sleep state.

[0029] Furthermore, during step S3, the AC charging phase, if an unrecoverable fault occurs in the OBC, the process proceeds to S5, the OBC fault handling phase:

[0030] S5a, OBC reports the fault to VCU, VCU receives the OBC fault command and sends a stop charging instruction to BMS;

[0031] S5b. After receiving the stop charging command, the BMS sends a clear OBC working mode command to the OBC, turns off the S2 switch, and reports the S2 switch status to the VCU.

[0032] S5c, after OBC receives the clear working mode, if there is no other instruction within the set time, OBC enters the dormant state;

[0033] S5d, VCU receives the S2 switch disconnection information and sends the contactor disconnection instruction to the BMS. If there is no other instruction within the set time, the VCU enters the sleep state;

[0034] S5e: After receiving the contactor disconnect command, BMS executes the contactor disconnection. If there is no other command within the set time, BMS enters the sleep state.

[0035] Furthermore, during the AC charging phase in step S3, if the electronic lock fails or the user presses the electronic lock switch, causing poor contact of the electronic lock switch, the process proceeds to S6, the electronic lock failure or electronic lock pressing processing phase:

[0036] S6a, BMS checks for electronic lock failure and sends a command to clear the OBC working mode to the OBC;

[0037] S6b: After receiving the command to clear the OBC working mode, the OBC stops charging and reports the OBC standby state to the BMS. If there is no other command within the set time, the OBC enters the sleep state.

[0038] S6c, BMS receives the OBC standby status, unlocks the electronic lock, turns off the S2 switch, and reports the S2 switch status information to the VCU;

[0039] S6d, VCU receives the S2 switch disconnection information and sends a BMS contactor disconnection instruction to the BMS. If there is no other instruction within the set time, the VCU enters the sleep state;

[0040] S6e: After receiving the contactor disconnect command, BMS executes the contactor disconnection. If there is no other command within the set time, BMS enters the sleep state.

[0041] Furthermore, during step S3, the AC charging stage, if an irreversible fault occurs in the DC / DC or BMS, the process proceeds to S7, the DC / DC or BMS fault handling stage:

[0042] S7a: The VCU detects DC / DC or BMS fault information, sends a stop charging command to the BMS, sends a clear working mode command to the OBC, disconnects the S2 switch, and sends a contactor disconnect command to the BMS. If there are no other commands within the set time, the VCU enters the sleep state;

[0043] S7b: BMS receives the stop charging command and stops charging. After receiving the disconnect contactor command, it disconnects the contactor. If there is no other command within the set time, BMS enters the sleep state.

[0044] S7c: The OBC receives the command to clear the working mode and stops charging. If there is no other command within the set time, the OBC enters the sleep state.

[0045] The beneficial effects of the present invention are:

[0046] In the present invention, CC / CP is controlled by BMS, which triggers AC charging. VCU, OBC and BCM exchange information with each other to complete AC charging.

[0047] The present invention provides an AC slow charging method for electric vehicles; the safety of AC charging is improved through the technical solutions of waking up stage, charging condition judgment stage, AC charging stage, charging stop stage, charging dormancy stage, OBC upload is unrecoverable, user unlocks the electronic lock, DC / DC or BMS generates a fault and stops charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0049] Figure 1 is a schematic diagram of the awakening stage in an embodiment;

[0050] Figure 2 Schematic diagram of the charging condition determination stage in the embodiment;

[0051] Figure 3 Schematic diagram of the AC charging stage in the embodiment;

[0052] Figure 4 Schematic diagram of the charging stop and charging dormancy stages in the embodiment;

[0053] Figure 5 Schematic diagram of the OBC fault handling stage in the embodiment;

[0054] Figure 6 Schematic diagram of the processing stage of an electronic lock failure or pressing the electronic lock in the embodiment;

[0055] Figure 7 Schematic diagram of a DC / DC or BMS fault handling stage in an embodiment; DETAILED DESCRIPTION

[0056] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0057] like Figures 1 to 7 As shown, according to an embodiment of the present invention, a method for AC slow charging of an electric vehicle is provided, characterized in that it includes the following steps:

[0058] S1, awakening stage

[0059] S1a, the user inserts the charging gun and wakes up the BMS through CC / CP;

[0060] S1b, after successfully waking up the BMS, the BMS initializes self-test. After the self-test is completed, the VCU is awakened through CAN information. If the BMS fails to wake up, it determines whether the wake-up signal is valid. If the wake-up signal is valid, the BMS performs initialization self-test. If the wake-up signal is invalid, the BMS enters the sleep stage.

[0061] S1c, VCU performs initialization self-test. After the initialization self-test is completed, it sends a wake-up signal to BMS and OBC through network management or output hard line. If the initialization self-test is not completed, the initialization self-test fails.

[0062] S1d, if the BMS receives a valid wake-up signal from the VCU, the power supply device outputs a 12V constant-level CP signal. The BMS checks the CC / CP status and uploads the CP status duty cycle, frequency, peak voltage information, CC resistance status, maximum grid current, and maximum cable current to the CAN bus, and sends the CC status and CP status to the OBC. If the BMS receives an invalid wake-up signal from the VCU, it continues to wake up the VCU through CAN information. The OBC receives the wake-up command, initializes the self-test, and after the initialization and self-test are completed, uploads the OBC status and fault information to the VCU. The OBC receives the CC status and CP status provided by the BMS and reports the OBC working status to the OBC.

[0063] S2. Charging condition determination stage

[0064] S2a. If the BMS receives the OBC feedback signal and the PWM type CP signal output by the power supply device and detects the CP duty cycle, it executes the electronic lock closing command, and the electronic lock is closed and fed back to the VCU. If the BMS does not receive the OBC feedback signal and the PWM type CP signal output by the power supply device and detect the CP duty cycle, the BMS enters the sleep state and sends a fault message to the CAN bus. The electric vehicle dashboard displays a text prompt: The charging gun is abnormal, charging is prohibited;

[0065] S2b, after receiving the electronic lock closing signal, the VCU sends a signal to prohibit the motor from outputting torque, exits the "READY" state, and sends a high-voltage pre-charge command to the BMS;

[0066] S2c and BMS receive the high-voltage pre-charge command, perform pre-charge, and feedback the pre-charge completion to VCU;

[0067] S2d, VCU receives the pre-charge completion instruction and issues the power battery contactor closing instruction. After receiving the command, BMS closes the power battery contactor, closes the S2 switch, and sends the S2 switch status information to VCU and OBC;

[0068] S2e: If the status information of the S2 switch is valid, the OBC receives the information that the S2 switch is closed, the power supply equipment contactor is closed, and the AC voltage starts to be output, and reports the AC port high-voltage interlock signal, OBC fault status and power supply equipment voltage to the VCU; if the status information of the S2 switch is invalid, the BMS enters the sleep state;

[0069] S3, AC charging stage

[0070] S3a, VCU receives the information reported by OBC, sends the slow charging start instruction to BMS and sends the DC output enable signal to DC / DC converter;

[0071] S3b. If the BMS receives a valid instruction to allow charging, it sends the charging mode, charging voltage, and charging current values ​​to the OBC. If the BMS receives an invalid instruction to allow charging, it enters a dormant state.

[0072] After receiving the charging working mode, S3c and OBC start working, perform charging, and report the charging status to BMS;

[0073] S3d and BMS estimate the remaining charging time and exchange charging information with OBC. The charging indicator light on the electric vehicle dashboard lights up and displays a text prompt that it is charging. It also displays the charging voltage, charging current, and remaining charging time.

[0074] S3e and BMS determine whether the battery is fully charged. If not, the battery continues to charge. After the battery is fully charged, the BMS sends a full charge feedback to the VCU.

[0075] S4, charging stop and charging sleep stage

[0076] S4a, VCU receives the full charge command from BMS and sends the stop AC charging and clear AC charging instructions to BMS;

[0077] S4b, after receiving the stop charging command, BMS sends a clear charger working mode to OBC;

[0078] S4c, after receiving the clear working mode, OBC stops charging and reports the OBC standby state. After a delay of 3s without other instructions, OBC enters the sleep state;

[0079] S4d, BMS receives the OBC standby status, executes the disconnection of S2 switch, and reports the S2 switch information to VCU;

[0080] S4e and VCU receive the S2 switch disconnection information, send a stop DCDC enable output signal to the DC / DC converter, and send a contactor disconnection instruction to the BMS. After a delay of 3 seconds and no other instructions, the VCU enters the sleep state;

[0081] S4f, after receiving the contactor disconnect command, BMS executes the contactor disconnection. After a delay of 3s, if there is no other instruction, BMS enters the sleep state.

[0082] During step S3, the AC charging phase, if an unrecoverable fault occurs in the OBC, the process proceeds to S5, the OBC fault handling phase:

[0083] S5a, OBC reports the fault to VCU, VCU receives the OBC fault command and sends a stop charging instruction to BMS;

[0084] S5b. After receiving the stop charging command, the BMS sends a clear OBC working mode command to the OBC, turns off the S2 switch, and reports the S2 switch status to the VCU.

[0085] S5c, after OBC receives the clear working mode, if there is no other instruction after a delay of 3s, OBC enters the sleep state;

[0086] S5d, VCU receives the S2 switch disconnection information and sends the contactor disconnection instruction to the BMS. After a delay of 3s, if there is no other instruction, the VCU enters the sleep state;

[0087] S5e: After receiving the contactor disconnect command, BMS executes the contactor disconnection. If there is no other command within the set time, BMS enters the sleep state.

[0088] During the AC charging phase in step S3, if the electronic lock fails or the user presses the electronic lock switch, causing poor contact of the electronic lock switch, the process proceeds to S6, the electronic lock failure or electronic lock pressing processing phase:

[0089] S6a, BMS checks for electronic lock failure and sends a command to clear the OBC working mode to the OBC;

[0090] S6b: After receiving the command to clear the OBC working mode, the OBC stops charging and reports the OBC standby state to the BMS. If there is no other command within the set time, the OBC enters the sleep state.

[0091] S6c, BMS receives the OBC standby status, unlocks the electronic lock, turns off the S2 switch, and reports the S2 switch status information to the VCU;

[0092] S6d, VCU receives the S2 switch disconnection information and sends the BMS a command to disconnect the BMS contactor. After a delay of 3s, if there is no other command, the VCU enters the sleep state;

[0093] S6e, after BMS receives the contactor disconnect command, it executes the contactor disconnection. After a delay of 3s, if there is no other instruction, BMS enters the sleep state.

[0094] During step S3, the AC charging phase, if an irreversible fault occurs in the DC / DC or BMS, the process proceeds to S7, the DC / DC or BMS fault handling phase:

[0095] S7a: The VCU detects DC / DC or BMS fault information, sends a stop charging command to the BMS, sends a clear working mode command to the OBC, turns off the S2 switch, and sends a contactor disconnect command to the BMS. If there is no other command after a delay of 3 seconds, the VCU enters the sleep state.

[0096] S7b: BMS receives the stop charging command and stops charging. After receiving the disconnect contactor command, it disconnects the contactor. After a delay of 3 seconds and no other instructions, BMS enters the sleep state.

[0097] S7c: OBC receives the command to clear the working mode and stops charging. After a delay of 3 seconds and no other instructions, OBC enters the sleep state.

[0098] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for AC slow charging of electric vehicles, characterized in that: The following steps are involved: S1, awakening stage S1a, the user inserts the charging gun and wakes up the BMS through CC / CP; S1b, after successfully waking up the BMS, the BMS initializes self-test. After the self-test is completed, the VCU is awakened through CAN information. If the BMS fails to wake up, it determines whether the wake-up signal is valid. If the wake-up signal is valid, the BMS performs initialization self-test. If the wake-up signal is invalid, the BMS enters the sleep stage. S1c, VCU performs initialization self-test. After the self-test is completed, it sends a wake-up signal to BMS and OBC through network management or output hard line. If the initialization self-test is not completed, the initialization self-test fails. S1d, if the BMS receives a valid wake-up signal from the VCU, the BMS receives a constant-level CP signal output by the power supply device, checks the CC / CP status, and uploads the CP status duty cycle, frequency, peak voltage information, CC resistance status, maximum grid current, and maximum cable current to the CAN bus, and sends the CC status and CP status to the OBC. If the BMS receives an invalid wake-up signal from the VCU, it continues to wake up the VCU through CAN information. The OBC receives the wake-up command, initializes the self-test, and after the initialization and self-test are completed, uploads the OBC status and fault information to the VCU. The OBC receives the CC status and CP status provided by the BMS and reports the OBC working status to the OBC. S2. Charging condition determination stage S2a. If the BMS receives the OBC feedback signal and the PWM type CP signal output by the power supply device and detects the CP duty cycle, it executes the electronic lock closing command, and the electronic lock is closed and fed back to the VCU. If the BMS does not receive the OBC feedback signal and the PWM type CP signal output by the power supply device and detect the CP duty cycle, the BMS enters the sleep state. S2b, after receiving the electronic lock closing signal, the VCU sends a signal to prohibit the motor from outputting torque, exits the "READY" state, and sends a high-voltage pre-charge command to the BMS; S2c and BMS receive the high-voltage pre-charge command, perform pre-charge, and feedback the pre-charge completion to VCU; S2d, VCU receives the pre-charge completion instruction and issues the power battery contactor closing instruction. After receiving the command, BMS closes the power battery contactor, closes the S2 switch, and sends the S2 switch status information to VCU and OBC; S2e: If the status information of the S2 switch is valid, the OBC receives the information that the S2 switch is closed, the power supply equipment contactor is closed, and the AC voltage starts to be output, and reports the AC port high-voltage interlock signal, OBC fault status and power supply equipment voltage to the VCU; if the status information of the S2 switch is invalid, the BMS enters the sleep state; S3, AC charging stage S3a, VCU receives the information reported by OBC, sends the slow charging start instruction to BMS and sends the DC output enable signal to DC / DC converter; S3b. If the BMS receives a valid instruction to allow charging, it sends the charging mode, charging voltage, and charging current values ​​to the OBC. If the BMS receives an invalid instruction to allow charging, it enters a dormant state. After receiving the charging working mode, S3c and OBC start working, perform charging, and report the charging status to BMS; S3d and BMS estimate the remaining charging time and exchange charging information with OBC; S3e and BMS determine whether the battery is fully charged. If not, the battery continues to charge. After the battery is fully charged, the BMS sends a full charge feedback to the VCU. S4, charging stop and charging sleep stage S4a, VCU receives the full charge command from BMS and sends the stop AC charging and clear AC charging instructions to BMS; S4b, after receiving the stop charging command, BMS sends a clear charger working mode to OBC; S4c, after receiving the clear working mode, OBC stops charging and reports the OBC standby state. If there is no other instruction within the set time, OBC enters the sleep state; S4d, BMS receives the OBC standby status, executes the disconnection of S2 switch, and reports the S2 switch information to VCU; S4e and VCU receive the S2 switch disconnection information, send a stop DCDC enable output signal to the DC / DC converter, and send a BMS contactor disconnection instruction to the BMS. If there is no other instruction within the set time, the VCU enters the sleep state; S4f, after receiving the contactor disconnect command, BMS executes the contactor disconnection. If there is no other instruction within the set time, BMS enters the sleep state.

2. The AC slow charging method for electric vehicles according to claim 1, characterized in that: During step S3, the AC charging phase, if an unrecoverable fault occurs in the OBC, the process proceeds to S5, the OBC fault handling phase: S5a, OBC reports the fault to VCU, VCU receives the OBC fault command and sends a stop charging instruction to BMS; S5b. After receiving the stop charging command, the BMS sends a clear OBC working mode command to the OBC, turns off the S2 switch, and reports the S2 switch status to the VCU. S5c, after OBC receives the clear working mode, if there is no other instruction within the set time, OBC enters the dormant state; S5d, VCU receives the S2 switch disconnection information and sends the contactor disconnection instruction to the BMS. If there is no other instruction within the set time, the VCU enters the sleep state; S5e: After receiving the contactor disconnect command, BMS executes the contactor disconnection. If there is no other command within the set time, BMS enters the sleep state.

3. The AC slow charging method for electric vehicles according to claim 1, characterized in that: During the AC charging phase in step S3, if the electronic lock fails or the user presses the electronic lock switch, causing poor contact of the electronic lock switch, the process proceeds to S6, the electronic lock failure or electronic lock pressing processing phase: S6a, BMS checks for electronic lock failure and sends a command to clear the OBC working mode to the OBC; S6b: After receiving the command to clear the OBC working mode, the OBC stops charging and reports the OBC standby state to the BMS. If there is no other command within the set time, the OBC enters the sleep state. S6c, BMS receives the OBC standby status, unlocks the electronic lock, turns off the S2 switch, and reports the S2 switch status information to the VCU; S6d, VCU receives the S2 switch disconnection information and sends a BMS contactor disconnection instruction to the BMS. If there is no other instruction within the set time, the VCU enters the sleep state; S6e: After receiving the contactor disconnect command, BMS executes the contactor disconnection. If there is no other command within the set time, BMS enters the sleep state.

4. The AC slow charging method for electric vehicles according to claim 1, characterized in that: During step S3, the AC charging phase, if an irreversible fault occurs in the DC / DC or BMS, the process proceeds to S7, the DC / DC or BMS fault handling phase: S7a: The VCU detects DC / DC or BMS fault information, sends a stop charging command to the BMS, sends a clear working mode command to the OBC, disconnects the S2 switch, and sends a contactor disconnect command to the BMS. If there are no other commands within the set time, the VCU enters the sleep state; S7b: BMS receives the stop charging command and stops charging. After receiving the disconnect contactor command, it disconnects the contactor. If there is no other command within the set time, BMS enters the sleep state. S7c: The OBC receives the command to clear the working mode and stops charging. If there is no other command within the set time, the OBC enters the sleep state.

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