A plug-in hybrid electric vehicle fast charging and discharging control system and method

Abstract

The present invention provides a plug-in hybrid electric vehicle fast charging and discharging control system and method, which belongs to the automotive field. The system includes: a motor controller, a vehicle controller, a battery management system, a DC / DC converter, and an air-conditioning controller; the battery management system can be communicatively connected to the charging pile, and the battery management system is communicatively connected to the air-conditioning controller and the vehicle controller respectively; the vehicle controller is communicatively connected to the air-conditioning controller, the DC / DC converter, and the motor controller respectively. The present invention takes into account the handbrake state to avoid safety accidents caused by the vehicle sliding downhill during charging; when the vehicle slides downhill, the present invention introduces the vehicle speed state and terminates charging in time, avoiding charging safety accidents and greatly improving the user's charging experience; during the power-off process, the present invention needs to disconnect the fast charging relay first, and then disconnect the main positive, main negative or heating relay in sequence to avoid the danger of power-off.

Description

Technical Field

[0001] The present invention belongs to the field of automobiles, and in particular relates to a plug-in hybrid electric vehicle fast charging and discharging control system and method. Background Art

[0002] With the development of society and economy and the advancement of science and technology, the automotive industry has experienced rapid growth. However, gasoline vehicles use fossil fuels, which are non-renewable resources. They also emit large amounts of polluting gases, such as CO and NOx, which can cause environmental pollution. Therefore, the automotive industry is inevitably moving towards energy-saving and environmentally friendly new energy vehicles.

[0003] To promote the rapid development of the new energy vehicle industry, plug-in hybrid electric vehicles (PHEVs) have emerged. These vehicles offer excellent energy efficiency, possessing both an engine and an electric motor as their power sources. Under low-speed conditions on urban roads, they can operate in pure electric mode, achieving zero emissions and reducing fuel consumption. They are an effective way to address the environmental pollution caused by fossil energy shortages and exhaust emissions. Consequently, PHEVs have gradually become a new energy vehicle model that the country is vigorously promoting.

[0004] PHEVs place higher demands on battery power density, energy density, range, lifespan, and cost than hybrid electric vehicles (HEVs). Battery technology is crucial to the adoption and widespread adoption of PHEVs. PHEV batteries have significantly greater capacity than HEV batteries, so only vehicles equipped with fast-charging capabilities can meet user needs.

[0005] The fast charging strategy should ensure the safety of vehicle charging and discharging while meeting regulations. However, excessive focus on charging safety may also lead to designs that affect the user experience. For example, to prevent the vehicle from rolling down a slope during charging, the current charging strategy is bundled with the parking brake status. As a result, if the vehicle's parking brake fails or is not pulled, the charging process cannot be started, affecting the charging experience of users who do not pull the parking brake.

[0006] Therefore, it is necessary to design a strategy to change the handbrake judgment state in the PHEV fast charging process to vehicle speed judgment, so as to further improve the user experience of PHEV fast charging and increase the charging success rate. Summary of the Invention

[0007] The purpose of the present invention is to solve the difficulties existing in the above-mentioned prior art, and to provide a plug-in hybrid electric vehicle fast charging and power-on control system and method, which detects the working status of the fast charging pile, battery management system, charging status, vehicle speed, parking brake signal and other states, divides the system working status during the fast charging process of the whole vehicle, improves the fault tolerance performance of the fast charging and power-on process of the whole vehicle, and formulates different control methods for multi-dimensional fast charging scenarios to make safe and reliable control requests for the fast charging system, thereby improving the safety and robustness of the fast charging and power-on process of the whole vehicle.

[0008] The present invention is achieved through the following technical solutions:

[0009] A first aspect of the present invention provides a plug-in hybrid electric vehicle fast charging and discharging control system, the system comprising: a motor controller, a vehicle controller, a battery management system, a DC / DC converter, and an air conditioning controller;

[0010] The battery management system can be connected to the charging pile in communication, and the battery management system is connected to the air conditioning controller and the vehicle controller respectively;

[0011] The vehicle controller is communicatively connected with the air-conditioning controller, the DC / DC converter, and the motor controller respectively.

[0012] A second aspect of the present invention provides a method for controlling fast charging and discharging of a plug-in hybrid electric vehicle, wherein the method controls fast charging and discharging according to the working status of the charging pile, the battery management system, the charging status of the power battery, and the vehicle status.

[0013] Preferably, the method includes: a fast charging power-on step and a fast charging power-off step.

[0014] Preferably, the fast charging step includes:

[0015] S101, initialization after inserting the gun;

[0016] S102, detecting the voltage of a detection point on the charging pile;

[0017] S103, determine whether there is a charging prohibition fault, if so, enter the fast charging power-off step, if not, enter S104;

[0018] S104: Determine whether the vehicle's parking brake is engaged. If so, proceed to S105; if not, determine subsequent operations based on the vehicle speed.

[0019] S105: Determine whether the vehicle is in the high-voltage power-on Ready state. If yes, the vehicle first powers off the high voltage and then returns to S103. If not, proceed to S106.

[0020] S106, close the pre-charge relay and the main negative relay, and at the same time, the charging pile switches to the vehicle's high-voltage relay closed state;

[0021] S107, determine whether the pre-charge is successful. If so, the pre-charge failure count is cleared and the process proceeds to S108; if not, disconnect the pre-charge relay and the main negative relay in sequence, and add 1 to the pre-charge failure count. After the set time, reclose the pre-charge relay and the main negative relay, and then determine whether the pre-charge failure count is ≥ 3 times. If so, an alarm is issued and the process proceeds to the fast charge power-off step; if not, return to S107;

[0022] S108, first close the main positive relay, then open the pre-charge relay, and then close the fast charge relay;

[0023] S109, sending heating or no heat management status;

[0024] S110: If the first condition or the second condition is met, the vehicle controller controls the DC / DC converter to operate and controls the PTC power value;

[0025] S111: The power battery starts fast charging.

[0026] Preferably, the subsequent operation is determined according to the vehicle speed in S104 as follows:

[0027] If 0 < vehicle speed < 1km / h and duration T1 > 1s, or vehicle speed ≥ 1km / h, then enter the fast charging step;

[0028] If the vehicle speed = 0 km / h and the duration time T2 ≥ 2 s, then proceed to S105;

[0029] If the vehicle speed continues to fluctuate and the duration T3 ≥ 3 minutes, the fast charging and discharging step will be entered.

[0030] Preferably, the determination of whether the pre-charging is successful in S107 is as follows:

[0031] Determine whether the difference between the external voltage and the internal voltage of the battery is ≤ the set value. If so, it is determined that the pre-charge is successful. If not, it is determined that the pre-charge is unsuccessful.

[0032] Preferably, in S110:

[0033] The first condition is: the vehicle controller receives the "power connection" signal;

[0034] The second condition is: the vehicle controller receives the "battery pack heating relay status = 1" signal and the "battery pack thermal management status = heating" signal.

[0035] Preferably, in S110, the vehicle controller controls the operation of the DC / DC converter, and the operation of controlling the PTC power value includes:

[0036] The vehicle controller sends the "DCDC enable signal = 1 (enable)" signal and the "DC / DC converter request voltage = 13.8V" signal;

[0037] The vehicle controller sends the PTC power limit values for the passenger compartment electric heater and the water flow electric heater.

[0038] Preferably, the fast charging and discharging steps include:

[0039] S201, determine whether the charging end condition is met, if so, control the vehicle to enter S202, otherwise, return to S201;

[0040] S202, the battery management system sends a signal to the vehicle controller;

[0041] S203, the vehicle controller sends a "vehicle operation mode = power off" signal, a "DCDC enable signal = 0 (disabled)" signal, a "DC / DC converter request voltage = 0V" signal, and a high-voltage component shutdown signal;

[0042] S204: Determine whether the absolute value of the total current of the battery pack is ≥10A and the duration T4 is ≥5s. If so, the battery pack sends a level 6 fault and then proceeds to S205. If not, the vehicle controller sends a "battery high voltage power on / off command = request to disconnect the high voltage switch" signal and then proceeds to S205.

[0043] S205: First disconnect the fast charge relay, then disconnect the main positive relay, main negative relay, or heating relay. If the network sleep state is met, the battery management system goes into sleep mode.

[0044] S206. The vehicle controller sends a "motor active discharge request = request" signal. If the key is in the OFF position, the vehicle operation mode is the sleep mode. If the network sleep state is met, the vehicle controller goes into sleep mode.

[0045] Preferably, the operation of determining whether the charging end condition is met in S201 includes:

[0046] If any of the following conditions is met, the charging end condition is determined to be met:

[0047] The vehicle is fully charged;

[0048] The charging gun has been unplugged;

[0049] The vehicle has a charging fault.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] (1) The present invention takes into account the parking brake state to avoid safety accidents caused by the vehicle sliding down the slope during charging;

[0052] (2) When the vehicle rolls down a slope, the present invention introduces the vehicle speed status and terminates charging in time, thus avoiding charging safety accidents and greatly improving the user's charging experience;

[0053] (3) To avoid overcharging when the battery is fully charged, the present invention determines the battery SOC value before charging; during fast charging, the temperature of the battery pack is monitored to ensure that the battery pack temperature is within a safe and optimal range; before closing the fast charging relay, a pre-charged battery pack internal and external voltage difference test is performed to ensure fast charging safety; during the power-off process, the fast charging relay needs to be disconnected first, and then the main positive, main negative or heating relays are disconnected in sequence to avoid the danger of power off. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A structural diagram of the system of the present invention;

[0055] Figure 2 Power-on flow chart in the method of the present invention;

[0056] Figure 3 Power-off flow chart in the method of the present invention. DETAILED DESCRIPTION

[0057] The present invention is further described in detail below with reference to the accompanying drawings:

[0058] The present invention provides a plug-in hybrid electric vehicle fast charging and discharging control system. Figure 1 As shown, the system includes: a motor controller (MCU), a vehicle control unit (HCU), a battery management system (BMS), a DC / DC converter (DCDC), and an air conditioning controller (AC). The battery management system can communicate with a charging pile (such as a DC fast charging pile), and the battery management system can communicate with the air conditioning controller and the vehicle control unit respectively. The vehicle control unit can communicate with the air conditioning controller, DC / DC converter, and motor controller respectively.

[0059] Specifically, the signals sent by the charging pile to the battery management system include: charger handshake, charger identification, charger maximum output capacity, charger output readiness status, charger charging status, and charger charging suspension. The signals sent by the battery management system to the charging pile include: vehicle handshake, battery management system and vehicle identification messages, power battery charging parameters, battery charging readiness status, battery charging requirements, overall battery charging status, power battery status information, single power battery voltage, power battery reserved messages, and battery management system charging suspension.

[0060] The information sent by the battery management system to the vehicle controller includes: battery management system fast charge connection status, battery pack pre-charge relay status, battery pack main positive relay status, battery pack main negative relay status, battery pack heating relay status, battery pack fast charge relay status, battery pack total current, battery management system charge current request, battery management system charge voltage request, battery pack key status, battery management system pre-charge status, battery management system operating status, battery pack thermal management status, battery pack status = power connection, and battery pack fault level. Signals sent by the vehicle controller to the battery management system include: vehicle operating mode and battery high-voltage power on and off instructions.

[0061] The signals sent by the battery management system to the air conditioning controller include: battery pack thermal management status.

[0062] The signals sent by the vehicle controller to the air conditioning controller include: electric compressor power limit and PTC power limit.

[0063] The signals sent by the vehicle controller to the DC / DC converter include: DC / DC converter enable and DC / DC converter voltage request. The signals sent by the DC / DC converter to the vehicle controller include: DC / DC converter status.

[0064] The signal sent by the vehicle controller to the motor controller includes: a motor active discharge request.

[0065] The present invention also provides a method for controlling fast charging and powering on and off of a plug-in hybrid electric vehicle. The method controls fast charging and powering on and off according to the working status of the charging pile, the battery management system (battery management system system), the charging status of the power battery, and the vehicle status (vehicle speed, parking brake signal), thereby improving the fault tolerance performance of the fast charging and powering on and off process of the entire vehicle, and formulating different control processes for the multi-dimensional scenarios of fast charging, making safe and reliable control requests to the fast charging system, and improving the safety and robustness of fast charging and powering on and off of the entire vehicle.

[0066] The method comprises: a fast charging power-on step and a fast charging power-off step.

[0067] like Figure 2 As shown, the fast charging step includes:

[0068] S101, initialization after inserting the gun:

[0069] After the fast charging gun is inserted into the charging pile (i.e., plug-in gun), the charging gun wakes up the network; the battery management system (BMS) and vehicle controller (VCU) on the vehicle are woken up and initialized, and the low-voltage self-test passes;

[0070] S102: Detect the voltage at the detection point on the charging pile:

[0071] If the voltage at test point 1 on the charging pile is 4V (according to the standard "GBT 18487.1-2015 Electric Vehicle Conductive Charging System Part 1: General Requirements" B3.2, the voltage value of test point 1 is used to determine whether the vehicle plug and vehicle socket are fully connected. If it is not 4V, it means that the vehicle charging interface is not connected), the charging pile sends a charger recognition message (CRM) stop signal. At this time, the battery management system sends a charging handshake recognition success (BRM) stop signal, indicating that the charging handshake is successful;

[0072] If the voltage of detection point 2 on the charging pile (detection points 1 and 2 are two detection points on the existing charging pile) is 6V (according to the standard "GBT 18487.1-2015 Electric Vehicle Conductive Charging System Part 1: General Requirements" B3.3, if the voltage of detection point 2 is not 6V, it means that the fast charging connection cable is not connected and charging cannot be performed.), that is, it is confirmed that the fast charging connection cable is connected, then the battery management system sends a "fast charging connection status (CC2) = 1 (connected)" signal. At the same time, after the battery management system receives the charger identification message (CRM) signal sent by the charging pile and the SOC real value and SOC display value of the power battery are both less than 100% (these two values are calculated internally by the battery management system), the battery management system sends a "fast charging ready" signal;

[0073] The above signals are all specified in the standard "GBT 27930-2015, 'Communication Protocol between Off-Board Conductive Chargers and Battery Management Systems for Electric Vehicles.'" The charger will only send a charger identification message stop signal after the charger and battery management system have successfully completed the charging handshake identification process. The charger will only send a charger identification message after the handshake message identification process between the charger and battery management system has been successfully completed.

[0074] S103: Determine whether there is a charging prohibition fault. If yes, proceed to the fast charging power-off step. If not, proceed to S104, as follows:

[0075] After the vehicle controller receives the "fast charging connection status (CC2) = 1 (connected)" signal and the "fast charging rechargeable" signal sent by the battery management system, it uses existing technology to detect the charging status and charging faults to determine whether there is a charging prohibition fault. If so, it enters the fast charging power-off step. If not, it enters S104.

[0076] S104: Determine whether the vehicle's parking brake is engaged. If so, proceed to S105; if not, determine subsequent operations based on the vehicle speed.

[0077] The subsequent operations are determined according to the vehicle speed as follows:

[0078] If 0 < vehicle speed < 1km / h and duration T1 > 1s, or vehicle speed ≥ 1km / h, then enter the fast charge and power-off step. This is done by judging the vehicle speed to determine whether the vehicle is slipping (sliding down a slope). Once slipping occurs, the entire vehicle will be prohibited from charging, i.e., enter the fast charge and power-off step;

[0079] If the vehicle speed is 0 km / h and the duration T2 is ≥ 2 seconds, then the process proceeds to S105. The vehicle speed is 0 for 2 seconds, which indicates that the vehicle is stationary. Even if the driver does not apply the handbrake, the vehicle is stationary (if the vehicle is on a level surface, the vehicle will not roll away without applying the handbrake), charging is permitted, so the process proceeds to S105.

[0080] If the vehicle speed continues to fluctuate (if the vehicle speed is constantly changing, it is determined to be a continuous fluctuation.) and the duration T3 ≥ 3min (after charging, if the vehicle speed fluctuation continues for more than 3 minutes, the vehicle may slip and no longer meet the charging conditions), then enter the fast charging and discharging step.

[0081] S105. Determine whether the vehicle is in the high-voltage powered-on Ready state (the vehicle controller can detect the READY state signal). If so, the vehicle first powers down the high voltage (the vehicle controller first requests the battery management system to disconnect the high-voltage relay, and the battery management system then executes the high-voltage relay disconnection action, and the vehicle powers down the high voltage), and then returns to S103. If not, enter S106.

[0082] S106: The vehicle controller sets the vehicle operation mode to "charging" and sends a battery high-voltage power-on / power-off command ("request to close the high-voltage switch"). After receiving the "request to close the high-voltage switch" from the vehicle controller, the battery management system closes the pre-charge relay and the main negative relay. At the same time, the charging station switches to the vehicle's high-voltage relay closed state.

[0083] S107, the battery management system determines whether the pre-charge is successful. If so, the pre-charge failure count is cleared, and then enters S108; if not, the battery management system disconnects the pre-charge relay and the main negative relay in sequence, and adds 1 to the pre-charge failure count. After a set time (for example, 500ms), the pre-charge relay and the main negative relay are reclosed, and then it is determined whether the pre-charge failure count is ≥ 3 times. If so, an alarm is issued (for example, "pre-charge failure" (pre-charge status)" && "battery pack alarm level = 9"), the alarm does not sleep or eliminate, and enters the fast charge power-off step at the same time; if not, it returns to S107. After the fault is cleared, the whole vehicle is powered on again, the historical fault is cleared, the pre-charge failure count is cleared, and the whole vehicle is allowed to go through the charging process again.

[0084] The specific steps for determining whether pre-charging is successful are as follows:

[0085] Determine whether the difference between the external voltage and the internal voltage of the battery is ≤ the set value (for example, 8V. The set value is to be calibrated and needs to be selected based on the characteristics of the power battery pack and the environment of the high-voltage circuit of the whole vehicle. It needs to be selected after multiple tests. The set value of each manufacturer may be different). If yes, it is determined that the pre-charge is successful. If not, it is determined that the pre-charge is unsuccessful.

[0086] S108: The battery management system first closes the main positive relay, then opens the pre-charge relay, then closes the fast charge relay, and finally sends a "power connection" signal to the vehicle controller;

[0087] S109. The battery management system sends a heating or no-heat management state according to the battery pack temperature (the battery pack temperature is detected by the battery management system);

[0088] S110: If the first condition or the second condition is met, the vehicle controller controls the DCDC operation and the PTC power value, as follows:

[0089] The first condition is: the vehicle controller receives the "power connection" signal;

[0090] The second condition is: the vehicle controller receives the "battery pack heating relay status = 1" signal and the "battery pack thermal management status = heating" signal, among which the "battery pack heating relay status = 1" signal is sent by the battery management system.

[0091] The vehicle controller controls the DCDC operation and the PTC power value, including the following operations:

[0092] The vehicle controller sends the "DCDC enable signal = 1 (enable)" signal and the "DC / DC converter request voltage = 13.8V" signal. These signals and values are sent to the DC / DC converter DCDC;

[0093] The vehicle controller sends the PTC power limit values for the passenger compartment electric heater and the water flow electric heater. These signals and values are sent to the air conditioning controller AC;

[0094] S111: The power battery starts fast charging.

[0095] like Figure 3 As shown, the fast charging power-off steps include:

[0096] S201, determine whether the charging end condition is met, if so, control the vehicle to enter S202, otherwise, return to S201;

[0097] The operations for determining whether the charging end condition is met include:

[0098] If any of the following conditions is met, the charging end condition is determined to be met:

[0099] The vehicle is fully charged;

[0100] The charging gun has been unplugged;

[0101] The vehicle has a charging fault.

[0102] Charging failures include: charger failure, battery management system failure, motor controller failure, and high-voltage interlock failure. In addition, the vehicle controller determines whether the vehicle is fully charged.

[0103] S202: The battery management system sends a signal to the vehicle controller. Different signals are sent based on the conditions in S201. Specifically, if the vehicle controller determines that vehicle charging is complete, the battery management system sends a signal indicating "charging complete" and "not charging" and sets the thermal management signal to "no request." If other conditions are met, the battery management system sends a signal indicating "charging interrupted or faulty, resulting in power off" and "not charging" and sets the thermal management signal to "no request."

[0104] S203: The vehicle controller sends a "vehicle operation mode = power off" signal (this signal is sent to the CAN network and can be received by all modules connected to the CAN network), a "DCDC enable signal = 0" signal (i.e., disabled or not working), and a "DC / DC converter request voltage = 0V" signal (sent to the DC / DC converter DCDC). The vehicle controller sends a high-voltage component shutdown signal, which includes a "electric compressor power limit = 0" signal, an "air conditioner PTC power limit = 0" signal, and a "water PTC power limit = 0" signal. These signals are sent to the air conditioner controller AC.

[0105] S204: Determine whether the absolute value of the total current of the battery pack is ≥10A and the duration T4 is ≥5s. If so, the battery pack sends a level 6 fault (i.e., a power-off timeout fault) and then proceeds to S205. If not, the vehicle controller sends a "battery high-voltage power-on and power-off command = request to disconnect the high-voltage switch" signal and then proceeds to S205.

[0106] S205: First disconnect the fast charge relay, then disconnect the main positive relay, main negative relay, or heating relay. If the network sleep state is met, the battery management system goes into sleep mode.

[0107] S206: The vehicle controller sends a "Motor Active Discharge Request = Request" signal. If the key is in the OFF position, the vehicle is in sleep mode. If the network sleep condition is met, the vehicle controller goes into sleep mode. The vehicle power mode signal sent from the PEPS module includes an OFF position signal. If this signal is received, indicating that the key is in the OFF position, the vehicle controller will go into sleep mode. If the key is not in the OFF position, the vehicle controller will not go into sleep mode.

[0108] The present invention ensures charging safety while improving the multi-dimensional charging experience by judging the "handbrake" or "vehicle speed" status; the power battery pre-charging system ensures the reliability and safety of the high-voltage power-on control of plug-in hybrid vehicles, avoids the MSD switch of the circuit from burning out, and maintains battery safety. In the process of disconnecting the high-voltage switch in the fast charging and power-off step, the main positive relay is disconnected first, and then the main negative relay is disconnected. This avoids the main positive relay from being impacted by large currents, which affects the life of the main positive relay, avoids the MSD switch of the circuit from burning out, and maintains battery safety. The present invention does not have a separate control module, which reduces costs.

[0109] The above technical solution is only one embodiment of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A method for controlling fast charging and discharging of a plug-in hybrid electric vehicle, characterized by: The method controls fast charging and discharging according to the working status of the charging pile, the battery management system, the charging status of the power battery, and the vehicle status, wherein the vehicle status includes the vehicle speed and the parking brake signal; When fast charging is controlled based on the vehicle status, if the vehicle's parking brake is not applied, fast charging is controlled based on the vehicle speed. The method comprises: a fast charging power-on step and a fast charging power-off step; The fast charging step includes: S101, initialization after inserting the gun; S102, detecting the voltage of a detection point on the charging pile; S103, determine whether there is a charging prohibition fault, if so, enter the fast charging power-off step, if not, enter S104; S104: Determine whether the vehicle's parking brake is engaged. If so, proceed to S105. If not, determine subsequent operations based on the vehicle speed, as follows: If 0 < vehicle speed < 1 km / h and duration T1 > 1s, or vehicle speed ≥ 1 km / h, then enter the fast charging step; If the vehicle speed = 0 km / h and the duration T2 ≥ 2s, proceed to S105; If the vehicle speed continues to fluctuate and the duration T3 ≥ 3 min, the system will enter the fast charging and discharging step; S105: Determine whether the vehicle is in the high-voltage power-on Ready state. If yes, the vehicle first powers off the high voltage and then returns to S103. If not, proceed to S106. S106, close the pre-charge relay and the main negative relay, and at the same time, the charging pile switches to the vehicle's high-voltage relay closed state; S107, determine whether the pre-charge is successful. If so, the pre-charge failure count is cleared and the process proceeds to S108; if not, disconnect the pre-charge relay and the main negative relay in sequence, and add 1 to the pre-charge failure count. After the set time, reclose the pre-charge relay and the main negative relay, and then determine whether the pre-charge failure count is ≥ 3 times. If so, an alarm is issued and the process proceeds to the fast charge power-off step; if not, return to S107; S108, first close the main positive relay, then open the pre-charge relay, and then close the fast charge relay; S109, sending heating or no heat management status; S110: If the first condition or the second condition is met, the vehicle controller controls the DC / DC converter to operate and controls the PTC power value; S111: The power battery starts fast charging.

2. The plug-in hybrid electric vehicle fast charging and discharging control method according to claim 1, characterized in that: Whether the pre-charging is successful is determined in S107 as follows: Determine whether the difference between the external voltage and the internal voltage of the battery is ≤ the set value. If so, it is determined that the pre-charge is successful. If not, it is determined that the pre-charge is unsuccessful.

3. The plug-in hybrid electric vehicle fast charging and discharging control method according to claim 1, characterized in that: In S110: The first condition is: the vehicle controller receives the "power connection" signal; The second condition is: the vehicle controller receives the "battery pack heating relay status = 1" signal and the "battery pack thermal management status = heating" signal.

4. The plug-in hybrid electric vehicle fast charging and discharging control method according to claim 1, characterized in that: The vehicle controller in S110 controls the operation of the DC / DC converter and the PTC power value, including the following operations: The vehicle controller sends the "DCDC enable signal = 1" signal and the "DC / DC converter request voltage = 13.8V" signal; The vehicle controller sends the PTC power limit values for the passenger compartment electric heater and the water flow electric heater.

5. The plug-in hybrid electric vehicle fast charging and discharging control method according to claim 1, characterized in that: The steps for fast charging and powering off include: S201, determine whether the charging end condition is met, if so, control the vehicle to enter S202, otherwise, return to S201; S202, the battery management system sends a signal to the vehicle controller; S203, the vehicle controller sends a "vehicle operation mode = power off" signal, a "DCDC enable signal = 0" signal, a "DC / DC converter request voltage = 0V" signal, and a high-voltage component shutdown signal; S204: Determine whether the absolute value of the total current of the battery pack is ≥10A and the duration T4 is ≥5s. If so, the battery pack sends a level 6 fault and the process proceeds to S205. If not, the vehicle controller sends a "battery high voltage power on / off command = request to disconnect the high voltage switch" signal and the process proceeds to S205. S205: First disconnect the fast charge relay, then disconnect the main positive relay, main negative relay, or heating relay. If the network sleep state is met, the battery management system goes into sleep mode. S206. The vehicle controller sends a "motor active discharge request = request" signal. If the key is in the OFF position, the vehicle operation mode is sleep mode. If the network sleep state is met, the vehicle controller goes into sleep mode.

6. The plug-in hybrid electric vehicle fast charging and discharging control method according to claim 5, characterized in that: The operation of determining whether the charging end condition is met in S201 includes: If any of the following conditions is met, the charging end condition is determined to be met: The vehicle is fully charged; The charging gun has been unplugged; The vehicle has a charging fault.

7. A plug-in hybrid electric vehicle fast charging and discharging control system, characterized by: The system includes: a motor controller, a vehicle controller, a battery management system, a DC / DC converter, and an air conditioning controller; The battery management system can be connected to the charging pile in communication, and the battery management system is connected to the air conditioning controller and the vehicle controller respectively; The vehicle controller is respectively connected to the air-conditioning controller, DC / DC converter, and motor controller; The system controls the fast charging and discharging of the plug-in hybrid electric vehicle by the method according to any one of claims 1 to 6.

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