Power system control method, control system and vehicle for hybrid vehicle

Abstract

This invention provides a powertrain control method, control system, and vehicle for a hybrid vehicle, relating to the field of vehicle control technology. The powertrain control method of this embodiment includes: determining whether a power battery has experienced a power-limited fault; when a power-limited fault is determined, performing torque control on a first motor and a second motor, while simultaneously disabling the anti-shake function of the second motor, so that the power generation of the first motor and the load power consumption remain consistent, and maintaining the current at the power battery bus terminal at zero; and performing voltage control on the first motor so that the difference between the actual voltage of the first motor and the set voltage is within a preset difference range. This control method can ensure normal vehicle operation while avoiding the problem of the vehicle being unable to drive or even experiencing power battery failure due to power-limited power, thus improving vehicle driving safety under power-limited conditions.

Description

[0001] This case is a divisional application of application number CN202210122532.7, filed on February 9, 2022, entitled "Powertrain Control Method, Control System and Vehicle for Hybrid Vehicles". Technical Field

[0002] This invention relates to the field of vehicle control technology, and in particular to a power system control method, control system, and vehicle for a hybrid vehicle. Background Technology

[0003] Currently, the battery technology for pure electric vehicles is complex and costly, thus hybrid systems are being widely promoted. Generally speaking, dual-motor hybrid systems have three motor modes: pure electric mode, series mode, and parallel mode. In series mode, the second motor drives the wheels, the clutch is not engaged, the engine charges the battery through the first motor, and the second motor drives the wheels. In parallel mode, the clutch is engaged, and the engine directly drives the wheels.

[0004] In actual use, when a power battery fails or its power is severely limited, the control system's handling of the power system is crucial, affecting the vehicle's safety and robustness.

[0005] When a vehicle is in extreme conditions, such as low temperatures (-30 to -35 degrees Celsius), the charging and discharging power of the power battery is significantly limited. It has been shown that below -35 degrees Celsius, the charging and discharging power of the power battery can be reduced to zero. Under these limited power conditions, the power battery cannot discharge to drive the secondary motor. Furthermore, even if the engine starts, the primary motor cannot charge the power battery. If the actual charging and discharging power of the power battery exceeds its limits, it will lead to battery failure. Summary of the Invention

[0006] One objective of the first aspect of the present invention is to provide a power system control method for hybrid vehicles, which solves the problem in the prior art where the power battery cannot be charged or discharged when a power limitation fault occurs, leading to battery failure.

[0007] Another objective of the first aspect of the present invention is to solve the problem of low vehicle safety caused by large voltage fluctuations in the first motor in the prior art.

[0008] A second aspect of the present invention is to provide a powertrain control system for a hybrid vehicle.

[0009] A third aspect of the present invention is to provide a vehicle that includes a powertrain control system for the hybrid vehicle.

[0010] Specifically, the present invention provides a powertrain control method for a hybrid vehicle, wherein the powertrain includes a power battery, an engine, a first motor, a second motor, a clutch, and a transmission, wherein the engine is connected to the first motor, the first motor is connected to the clutch and then to the transmission, and the second motor is directly connected to the transmission; the powertrain control method includes:

[0011] Determine whether the power battery has experienced a power limitation fault;

[0012] When the power battery is determined to have a power limitation fault, torque control is applied to the first motor and the second motor, and the anti-shake function of the second motor is turned off, so that the power generation of the first motor and the power consumption of the load are kept consistent, and the current at the bus terminal of the power battery is kept to zero.

[0013] The voltage of the first motor is controlled so that the difference between the actual voltage of the first motor and the set voltage is within a preset difference range.

[0014] The step of controlling the voltage of the first motor includes:

[0015] The on / off state of the vehicle's battery relay is obtained, and the battery relay switches between on and off at preset time intervals;

[0016] When the battery relay is in the closed state, the actual voltage of the first motor at the previous moment is used as the first target voltage at the current moment. The difference between the first target voltage and the actual voltage fed back at the current moment is used as the input of the closed-loop PID controller, thereby calculating the first target torque of the first motor at the current moment.

[0017] The first actual torque of the first motor at the current moment is obtained by adding the first feedforward torque of the first motor at the previous moment to the first target torque.

[0018] When the relay of the power battery is turned on, the second actual torque of the first motor is obtained by setting the voltage as the second target voltage at the current moment and using the same calculation method as the first actual torque.

[0019] While controlling the voltage of the first motor, it is determined whether the difference between the actual voltage of the first motor and the set voltage is within the set range. If not, an alarm is triggered after the set time threshold is exceeded.

[0020] Optionally, after determining whether the power battery has experienced a power-limited fault, the method further includes:

[0021] The power battery is determined to have a power limitation fault if all of the following conditions are met:

[0022] The maximum temperature of the power battery is less than a preset temperature threshold.

[0023] The maximum discharge power of the power battery is less than the first power threshold.

[0024] The absolute value of the maximum charging power of the power battery is less than the second power threshold.

[0025] Optionally, the vehicle further includes a DC-DC converter disposed between the first motor and the transmission;

[0026] The steps for torque control of the first motor and the second motor include:

[0027] The driving mode of the vehicle is obtained, wherein the driving mode includes pure electric driving mode, series driving mode, parallel driving mode and idle mode;

[0028] When the vehicle is in the pure electric drive mode, the series drive mode, or the idle mode, control the vehicle to enter the series drive mode; or when the vehicle is in the parallel drive mode, control the vehicle to maintain the parallel drive mode and limit the speed of the engine.

[0029] Torque control is performed on the engine, the first motor, and the second motor;

[0030] When the power output of the first motor corresponds to the sum of the power consumed at the low-voltage end of the DC-DC converter and the power consumed by the second motor, and the output or input current of the power battery is substantially zero, the torque of the first motor is applied to the crankshaft torque of the engine.

[0031] Optionally, the power system further includes a cooling system, which includes a cooling pump and is used to cool the first motor and the second motor.

[0032] The steps for torque control of the engine, the first motor, and the second motor include:

[0033] The engine speed is limited to a preset range;

[0034] When the engine speed is limited to a preset speed range, the vehicle is controlled to enter the parallel drive mode or the series drive mode.

[0035] Adjust the cooling pump speed to the maximum and control the voltage of the low-voltage end of the DC-DC converter to the first preset voltage (14V).

[0036] Control the torque adjustment of the second motor to the torque requested by the driver;

[0037] The output torque of the first motor is controlled and adjusted so that the power corresponding to the output torque of the first motor is the sum of the power consumed by the low-voltage end of the DC-DC converter and the power consumed by the second motor, while the output or input current of the power battery is controlled to be 0.

[0038] The control applies the actual torque of the first motor to the crankcase of the engine.

[0039] Optionally, the step of controlling the vehicle to enter the parallel drive mode or the series drive mode when the engine speed is limited within a preset range includes:

[0040] When the engine speed is within the preset range, determine whether the vehicle speed is greater than the preset speed;

[0041] When the vehicle speed is greater than the preset speed, the vehicle is controlled to enter the parallel drive mode;

[0042] When the vehicle speed is less than the preset speed, the vehicle is controlled to enter the series drive mode.

[0043] Optionally, the feedforward torque is the sum of the low-voltage load power of the DC-DC converter and the actual power of the second motor, divided by the actual speed of the first motor.

[0044] Optionally, after determining whether the fault of the power battery is a power-limited fault based on the fault signal, the method further includes:

[0045] When the fault of the power battery is determined to be the power limitation fault, the system receives the control signal sent by the power battery controller, controls the voltage of the power battery to be within a preset voltage threshold range, and controls the charging and discharging power of the power battery to be less than a preset power threshold.

[0046] In particular, the present invention also provides a powertrain control system for a hybrid vehicle, including a memory and a processor, wherein the memory stores a control program, and the control program, when executed by the processor, is used to implement the powertrain control method for the hybrid vehicle described above.

[0047] In particular, the present invention also provides a vehicle including the powertrain control system of the hybrid vehicle described above.

[0048] In this solution, when the power battery experiences a power limitation fault, torque control is applied to the first motor and the second motor, and the voltage of the first motor is further controlled. This ensures the normal operation of the vehicle while preventing the vehicle from becoming inoperable or even causing the power battery to fail due to power limitation, thereby improving the vehicle's driving safety under power limitation conditions.

[0049] In this solution, by continuously adjusting the target voltage value, the actual torque after adjustment is within the preset actual torque range, thus achieving the objective of this embodiment. That is, the torque of the first motor is within the preset actual torque range, so that when the vehicle's power battery experiences a power limitation fault, the power generation of the first motor and the power consumption of the load are balanced, keeping the current at the battery bus terminal at 0. At the same time, the actual voltage of the first motor is maintained within the threshold range of the target voltage, avoiding the problem of low vehicle safety caused by large voltage fluctuations of the first motor.

[0050] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0051] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0052] Figure 1 This is a schematic structural diagram of the power system of a dual-motor hybrid vehicle according to a specific embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram of the power transmission path for driving a vehicle in a series drive mode according to a specific embodiment of the present invention.

[0054] Figure 3 This is a schematic diagram of the power transmission path for driving a vehicle in a parallel drive mode according to a specific embodiment of the present invention.

[0055] Figure 4 This is a schematic diagram of the power transmission path for driving a vehicle in pure electric drive mode according to a specific embodiment of the present invention.

[0056] Figure 5 This is a schematic flowchart of a control method for the power system of a dual-motor hybrid vehicle according to a specific embodiment of the present invention;

[0057] Figure 6This is a schematic flowchart illustrating the steps of torque control of a first motor and a second motor according to a specific embodiment of the present invention.

[0058] Figure 7 This is a schematic flowchart illustrating the steps of torque control of an engine, a first motor, and a second motor according to a specific embodiment of the present invention.

[0059] Figure 8 This is a schematic flowchart illustrating the steps of controlling the voltage of a first motor according to another specific embodiment of the present invention. Detailed Implementation

[0060] As a specific embodiment of the present invention, the powertrain control method for a dual-motor hybrid vehicle in this embodiment is based on a dual-motor hybrid vehicle 100. For example... Figure 1 As shown, the dual-motor hybrid vehicle 100 may include a power battery 10, an engine 20, a first motor 30, a second motor 40, a clutch 50, and a transmission 60. The engine 20 is connected to the first motor 30, the first motor 30 is connected to the clutch 50 and then to the transmission 60, and the second motor 40 is directly connected to the transmission 60. Furthermore, the driving modes of this dual-motor hybrid vehicle may include parallel drive mode, series drive mode, pure electric drive mode, and idle mode. In series drive mode, as... Figure 2 As shown, the first motor 30 supplies power to the second motor 40, which in turn directly drives the transmission 60, thus propelling the vehicle. In parallel drive mode, as... Figure 3 As shown, engine 20 drives first motor 30, which in turn drives transmission 60, thereby propelling the vehicle. In pure electric drive mode, as... Figure 4 As shown, the power battery 10 can directly charge the second motor 40, and then use the second motor 40 to drive the transmission 60 to run, thereby driving the vehicle to move.

[0061] Specifically, such as Figure 5 As shown, the powertrain control method for a hybrid vehicle in this embodiment may include:

[0062] Step S100: Determine whether the power battery has a power limitation fault. If yes, proceed to step S200; otherwise, end the program.

[0063] Step S200: When it is determined that the power battery has a power limitation fault, torque control is performed on the first motor and the second motor, and the anti-shake function of the second motor is turned off so that the power generation of the first motor and the power consumption of the load are consistent, and the current at the power battery bus terminal is kept to zero.

[0064] Step S300 performs voltage control on the first motor so that the difference between the actual voltage of the first motor and the set voltage is within a preset difference range.

[0065] In this embodiment, when the power battery experiences a power limitation fault, torque control is applied to the first motor and the second motor, and the voltage of the first motor is further controlled. This ensures the normal operation of the vehicle while preventing the vehicle from being unable to drive or even causing the power battery to fail due to power limitation, thereby improving the vehicle's driving safety under power limitation conditions.

[0066] The process may further include, after step S100: when it is determined that the fault of the power battery is a power-limited fault, receiving a control signal sent by the power battery controller, controlling the voltage of the power battery within a preset voltage threshold range, and controlling the charging and discharging power of the power battery to be less than a preset power threshold.

[0067] As a specific embodiment of the present invention, step S100 of this embodiment, after determining whether the power battery has experienced a power limitation fault, may further include:

[0068] A power battery is considered to have a power limitation fault if all of the following conditions are met:

[0069] The maximum temperature of the power battery is lower than the preset temperature threshold. The maximum discharge power of the power battery is lower than the first power threshold. The absolute value of the maximum charging power of the power battery is lower than the second power threshold.

[0070] In this embodiment, the power battery can only be determined to have a power-limited fault if it simultaneously meets the above conditions. Specifically, the preset temperature threshold is -30 degrees Celsius, and the battery's charge and discharge power ratings are both below the threshold. The first and second power thresholds are both less than 7 kW.

[0071] Generally, the vehicle controller continuously monitors the status of the power battery and transmits this signal to the control system in this embodiment. When the control system in this embodiment determines that the power battery has a power-limited fault based on the signal from the vehicle controller, it controls the voltage of the first motor and also controls the voltage and charging / discharging power of the power battery. Specifically, it controls the voltage of the power battery to fluctuate within a certain range, specifically a set voltage threshold. This set voltage threshold can be set according to the situation. At the same time, it limits the charging / discharging power of the power battery to within a preset power threshold range. In this way, it ensures that the voltage and charging / discharging power of the power battery are within a certain range, avoiding situations where the power battery is over-voltage or the charging / discharging power is too high, which could lead to combustion or even explosion.

[0072] As a specific embodiment of the present invention, the vehicle of this embodiment also includes a DC-DC converter, which is disposed between the first motor and the transmission. This DC-DC converter converts high voltage to low voltage.

[0073] Specifically, such as Figure 6 As shown, in step S200, the step of torque control of the first motor and the second motor may include:

[0074] Step S201: Obtain the vehicle's drive mode, which includes pure electric drive mode, series drive mode, parallel drive mode and idle mode.

[0075] Step S202: When the vehicle is in pure electric drive mode, series drive mode or idle mode, control the vehicle to enter series drive mode; or when the vehicle is in parallel drive mode, control the vehicle to maintain parallel drive mode and limit the engine speed.

[0076] Step S203: Perform torque control on the engine, the first motor, and the second motor;

[0077] In step S204, when the power corresponding to the generating torque of the first motor is the sum of the power consumed at the low-voltage end of the DC-DC converter and the power consumed by the second motor, and the output or input current of the power battery is basically 0, the torque of the first motor is applied to the crankshaft torque of the engine.

[0078] Specifically, because the power battery cannot charge the second motor when it experiences a power limitation fault, it is necessary to switch to the appropriate drive mode when the vehicle is in different drive modes to meet the vehicle's normal operating requirements.

[0079] In this embodiment, the purpose of obtaining the vehicle's drive mode in step S201 is to perform different controls based on each different drive mode. Generally, the drive mode is controlled by the vehicle controller, so it can be obtained directly from the vehicle controller.

[0080] In step S202, when the vehicle is in series drive mode, pure electric drive mode, or idle mode, the vehicle drive mode can be switched to or maintained in series drive mode. This ensures that the first motor generates electricity to the second motor and the vehicle's electrical components, thereby keeping the bus current at zero to ensure normal vehicle power consumption and operation. When the vehicle is in parallel drive mode, since the vehicle does not need to use a power battery, it can maintain parallel drive mode. However, if the vehicle speed is too high and the energy requirements are high, it may easily switch to other drive modes; therefore, speed limiting is necessary.

[0081] In step S203, the torque control of the engine, the first motor and the second motor mainly involves switching the torque between each other during the drive mode switching process, which requires active control.

[0082] In step S204, the main purpose is to ensure that after the vehicle switches to a suitable driving mode, the power generated by the first motor can supply the entire vehicle, and the current at the power battery should be kept as low as possible to avoid damage to the power battery.

[0083] As a specific embodiment of the present invention, the power system of this embodiment further includes a cooling system, which includes a cooling pump and is used to cool the first motor and the second motor.

[0084] Specifically, such as Figure 7 As shown, step S203, the step of torque control of the engine, the first motor, and the second motor includes:

[0085] Step S2031: Limit the engine speed within a preset speed range;

[0086] Step S2032: When the engine speed is limited to a preset speed range, control the vehicle to enter parallel drive mode or series drive mode.

[0087] Step S2033: Adjust the cooling pump speed to the maximum and control the voltage of the low-voltage end of the DC-DC converter to the first preset voltage (14V).

[0088] Step S2034: Control the torque adjustment of the second motor to the torque requested by the driver;

[0089] Step S2035: Control and adjust the output torque of the first motor so that the power corresponding to the output torque of the first motor is the sum of the power consumed by the low voltage end of the DC-DC converter and the power consumed by the second motor, while controlling the output or input current of the power battery to be 0.

[0090] Step S2036: Control the actual torque of the first motor to be added to the crankcase of the engine.

[0091] In step S2031 of this embodiment, the preset speed range can be 0-5000 rpm.

[0092] When the engine speed is limited to a preset range, the vehicle's drive mode is controlled according to the vehicle's speed, so that the drive can better meet the vehicle's needs.

[0093] In step S2033, the adjustment of the cooling pump is to cool the first motor and the second motor, preventing them from overheating. This embodiment also maintains the voltage at the low-voltage end of the DC-DC converter at a first preset voltage, which is approximately 14V. This first preset voltage is set based on the actual vehicle's electrical voltage.

[0094] As a specific embodiment of the present invention, step S2032 of controlling the vehicle to enter parallel drive mode or series drive mode when the engine speed is limited to a preset range includes:

[0095] When the engine speed is within a preset range, determine whether the vehicle speed is greater than the preset speed;

[0096] When the vehicle speed exceeds the preset speed, the vehicle is controlled to enter parallel drive mode;

[0097] When the vehicle speed is less than the preset speed, the vehicle is controlled to enter the series drive mode.

[0098] The preset speed is usually 20km / h. This preset speed is the threshold speed for entering parallel drive mode.

[0099] As a specific embodiment of the present invention, such as Figure 8 As shown, step S300 of this embodiment, which controls the voltage of the first motor, includes:

[0100] Step S301: Obtain the open / closed state of the vehicle's battery relay. The battery relay switches between open and closed at preset intervals.

[0101] Step S302: When the battery relay is in the closed state, the actual voltage of the first motor at the previous moment is used as the first target voltage at the current moment. The difference between the first target voltage and the actual voltage fed back at the current moment is used as the input of the closed-loop PID controller, thereby calculating the first target torque of the first motor at the current moment.

[0102] Step S303: The first actual torque of the first motor at the current moment is obtained by adding the first feedforward torque of the first motor at the previous moment to the first feedforward torque.

[0103] Step S304: When the relay of the power battery is turned on, the second actual torque of the first motor is obtained by using the set voltage as the second target voltage at the current moment and the same calculation method as the first actual torque mentioned above.

[0104] Step S305: While performing the above actions, determine whether the difference between the actual voltage and the set voltage of the first motor is within the set range. If not, an alarm is triggered after the set time threshold is exceeded.

[0105] In step S302 of this embodiment, the actual torque equals the target torque plus the feedforward torque. The feedforward torque is equal to the sum of the low-voltage load power of the DC-DC converter and the actual power of the second motor, divided by the actual speed of the first motor. This ensures that the power generation of the first dispensing machine and the power consumption of the load are balanced, and keeps the current at the power battery bus terminal at 0. At this time, the engine torque is equal to the torque of the first motor multiplied by -1.

[0106] Similarly, when the power battery relay is open, using the same calculation method as above, the actual torque of the first motor at this time is equal to the sum of the feedforward torque and the torque calculated by the closed-loop PID controller. The feedforward torque is also the sum of the low-voltage load power of the DC-DC converter and the actual power of the second motor, divided by the actual speed of the first motor. This yields the actual torque when the power battery relay is open.

[0107] By continuously adjusting the target voltage value, the actual torque output when the relay is open and closed will not be exactly the same due to the adjustment of the set voltage. When the adjusted actual torque is within the preset actual torque range, the purpose of this embodiment is achieved, that is, the torque of the first motor is within the preset actual torque range, so that when the vehicle's power battery experiences a power limitation fault, the power generation of the first motor and the power consumption of the load are balanced, keeping the current at the battery bus terminal at 0, and at the same time, the actual voltage of the first motor is maintained within the threshold range of the target voltage, avoiding the problem of low vehicle safety caused by large voltage fluctuations of the first motor.

[0108] Specifically, if the difference between the actual voltage of the first motor and the set voltage is not within the preset range after adjustment, a fault alarm will be triggered. This indirectly indicates that the power limitation fault of the power battery cannot be eliminated by control adjustment. The driver or maintenance personnel need to be aware of the fault and carry out proactive maintenance to ensure the safety of the vehicle.

[0109] The control method in this embodiment proposes a power closed-loop control strategy when the charging and discharging power limit of the power battery is severely restricted, even to zero. This avoids the problems of the power battery being too low to drive the vehicle at low temperatures, and the vehicle being unable to drive due to a fault caused by exceeding the battery power limit at low temperatures. This improves the vehicle's safety and low-temperature driving performance.

[0110] As a specific embodiment of the present invention, this embodiment also provides a powertrain control system for a hybrid vehicle, including a memory and a processor. The memory stores a control program, which, when executed by the processor, is used to implement the powertrain control method for the hybrid vehicle described above. The processor can be a central processing unit (CPU), a digital processing unit, etc. The processor sends and receives data through a communication interface. The memory is used to store the program executed by the processor. The memory is any medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer; it can also be a combination of multiple memories. The aforementioned computational program can be downloaded from a computer-readable storage medium to a corresponding computing / processing device or downloaded to a computer or external storage device via a network (e.g., the Internet, a local area network, a wide area network, and / or a wireless network).

[0111] As a specific embodiment of the present invention, this embodiment may also provide a vehicle that may include the power system control system of the hybrid vehicle described above.

[0112] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A powertrain control method for a hybrid vehicle, wherein the powertrain includes a power battery, an engine, a first motor, a second motor, a clutch, and a transmission, wherein, The engine is connected to the first motor, the first motor is connected to the transmission after being connected to the clutch, and the second motor is directly connected to the transmission; characterized in that the power system control method includes: Determine whether the power battery has experienced a power limitation fault; When the power battery is determined to have a power limitation fault, torque control is applied to the first motor and the second motor, and the anti-shake function of the second motor is turned off, so that the power generation of the first motor and the power consumption of the load are kept consistent, and the current at the bus terminal of the power battery is kept to zero. The voltage of the first motor is controlled so that the difference between the actual voltage of the first motor and the set voltage is within a preset difference range. The steps for controlling the voltage of the first motor include: The on / off state of the vehicle's battery relay is obtained, and the battery relay switches between on and off at preset time intervals; When the battery relay is in the closed state, the actual voltage of the first motor at the previous moment is used as the first target voltage at the current moment. The difference between the first target voltage and the actual voltage fed back at the current moment is used as the input of the closed-loop PID controller, thereby calculating the first target torque of the first motor at the current moment. The first actual torque of the first motor at the current moment is obtained by adding the first feedforward torque of the first motor at the previous moment to the first target torque. When the relay of the power battery is turned on, the second actual torque of the first motor is obtained by setting the voltage as the second target voltage at the current moment and using the same calculation method as the first actual torque. While controlling the voltage of the first motor, it is determined whether the difference between the actual voltage of the first motor and the set voltage is within the set range. If not, an alarm is triggered after the set time threshold is exceeded.

2. The powertrain control method for a hybrid vehicle according to claim 1, characterized in that, After determining whether the power battery has experienced a power limitation fault, the method further includes: The power battery is determined to have a power limitation fault if all of the following conditions are met: The maximum temperature of the power battery is less than a preset temperature threshold. The maximum discharge power of the power battery is less than the first power threshold. The absolute value of the maximum charging power of the power battery is less than the second power threshold.

3. The powertrain control method for a hybrid vehicle according to claim 2, characterized in that, The vehicle also includes a DC-DC converter, which is disposed between the first motor and the transmission. The steps for torque control of the first motor and the second motor include: The driving mode of the vehicle is obtained, wherein the driving mode includes pure electric driving mode, series driving mode, parallel driving mode and idle mode; When the vehicle is in the pure electric drive mode, the series drive mode, or the idle mode, control the vehicle to enter the series drive mode; or when the vehicle is in the parallel drive mode, control the vehicle to maintain the parallel drive mode and limit the speed of the engine. Torque control is performed on the engine, the first motor, and the second motor; When the power output of the first motor corresponds to the sum of the power consumed at the low-voltage end of the DC-DC converter and the power consumed by the second motor, and the output or input current of the power battery is substantially zero, the torque of the first motor is applied to the crankshaft torque of the engine.

4. The powertrain control method for a hybrid vehicle according to claim 3, characterized in that, The power system also includes a cooling system, which includes a cooling pump and is used to cool the first motor and the second motor. The steps for torque control of the engine, the first motor, and the second motor include: The engine speed is limited to a preset range; When the engine speed is limited to a preset speed range, the vehicle is controlled to enter the parallel drive mode or the series drive mode. Adjust the cooling pump speed to the maximum and control the voltage at the low-voltage end of the DC-DC converter to a first preset voltage; Control the torque adjustment of the second motor to the torque requested by the driver; The output torque of the first motor is controlled and adjusted so that the power corresponding to the output torque of the first motor is the sum of the power consumed by the low-voltage end of the DC-DC converter and the power consumed by the second motor, while the output or input current of the power battery is controlled to be 0. The control applies the actual torque of the first motor to the crankcase of the engine.

5. The powertrain control method for a hybrid vehicle according to claim 4, characterized in that, The step of controlling the vehicle to enter the parallel drive mode or the series drive mode when the engine speed is limited to a preset range includes: When the engine speed is within the preset range, determine whether the vehicle speed is greater than the preset speed; When the vehicle speed is greater than the preset speed, the vehicle is controlled to enter the parallel drive mode; When the vehicle speed is less than the preset speed, the vehicle is controlled to enter the series drive mode.

6. The powertrain control method for a hybrid vehicle according to claim 1, characterized in that, The feedforward torque is the sum of the low-voltage load power of the DC-DC converter and the actual power of the second motor, divided by the actual speed of the first motor.

7. The powertrain control method for a hybrid vehicle according to claim 1, characterized in that, After determining whether the fault of the power battery is a power-limited fault based on the fault signal, the following steps are also included: When the fault of the power battery is determined to be the power limitation fault, the system receives the control signal sent by the power battery controller, controls the voltage of the power battery to be within a preset voltage threshold range, and controls the charging and discharging power of the power battery to be less than a preset power threshold.

8. A powertrain control system for a hybrid vehicle, characterized in that, It includes a memory and a processor, wherein the memory stores a control program, which, when executed by the processor, is used to implement the powertrain control method for the hybrid vehicle according to any one of claims 1-7.

9. A vehicle, characterized in that, Includes the powertrain control system of the hybrid vehicle as described in claim 8.

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