Power system control method and control system for dual-motor hybrid vehicle

Abstract

The application provides a power system control method and control system of a dual-motor hybrid vehicle, and relates to the technical field of vehicle control.The power system control method of the dual-motor hybrid vehicle comprises the following steps: obtaining a fault signal of a power battery of the vehicle; determining whether the fault of the power battery is a voltage control fault according to the fault signal; when it is determined that the fault of the power battery is the voltage control fault, controlling the voltage of a first motor, so that the power generation of the first motor and the load power consumption are consistent, and the power battery bus end current is kept to be zero.When the voltage fault of the power battery in the power system occurs, the voltage of the first motor of the vehicle is made to fluctuate within a certain range under the condition of ensuring the normal operation of the vehicle, the problem that the power system appears a serious fault due to exceeding the threshold value is avoided, and the safety of the vehicle is improved.

Description

[0001] This case is a divisional application with application number 202210122536.5, application date February 9, 2022, entitled "Powertrain Control Method and Control System for Dual-Motor Hybrid Vehicles". Technical Field

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

[0003] With increasingly stringent national regulations on fuel consumption and emissions, and the development of electrification systems, hybrid technology is key to achieving energy conservation and emission reduction, and both OEMs and component suppliers are seeking solutions. However, the battery technology for pure electric vehicles is currently complex and costly, hence the strong promotion of hybrid systems. Generally, 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] In practice, when a specific UDC (Voltage Direct Control) fault occurs in the power battery, if both motors continue to operate in torque control mode, the bus voltage can easily exceed the threshold due to the lack of the power battery as an energy "buffer," leading to an overvoltage fault. Therefore, the motors are requested to enter voltage control mode. However, directly controlling the motor voltage can easily cause problems such as battery overheating and severe voltage fluctuations. Summary of the Invention

[0006] One objective of the first aspect of the present invention is to provide a power system control method for a dual-motor hybrid vehicle, which solves the problem in the prior art where a power system failure occurs due to overvoltage caused by a voltage control failure of the power battery.

[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 dual-motor hybrid vehicle.

[0009] Specifically, the present invention provides a powertrain control method for a dual-motor hybrid vehicle. The powertrain of the vehicle includes a power battery, an engine, a first motor, a second motor, a clutch, and a transmission. 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:

[0010] Obtain fault signals from the vehicle's power battery;

[0011] Determine whether the fault of the power battery is a voltage control fault based on the fault signal;

[0012] When the fault of the power battery is determined to be the voltage control fault, the voltage of the first motor is controlled to ensure 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.

[0013] Optionally, the voltage control of the first motor includes the following steps:

[0014] The driving mode of the vehicle is obtained, wherein the driving mode includes pure electric driving mode, series driving mode and parallel driving mode;

[0015] When the vehicle is in the pure electric drive mode, series drive mode and parallel drive mode, the engine is controlled to be in the start state and the vehicle enters the parallel drive mode or the clutch slip control state.

[0016] Torque control is performed on the engine, the first motor, and the second motor;

[0017] When the torque of the second motor is completely unloaded and the output torque of the vehicle is entirely output by the engine, the voltage of the first motor is controlled.

[0018] Optionally, when the vehicle is in the pure electric drive mode, series drive mode, and parallel drive mode, the step of controlling the vehicle to enter the parallel drive mode drive state or the clutch slip control state includes:

[0019] When the vehicle is in the pure electric drive mode, the engine is requested to start. The vehicle's current speed is compared with a preset speed threshold, and the vehicle is controlled to enter either the parallel drive mode or the clutch slip control state.

[0020] When the vehicle is in the series drive mode, the engine is kept running, and the vehicle is controlled to enter the drive state of the parallel drive mode or the clutch slip control state by comparing the current vehicle speed with the preset vehicle speed threshold.

[0021] The preset speed threshold is the minimum speed at which the vehicle can enter the parallel drive mode.

[0022] Optionally, the power system further includes a DC-DC converter and a cooling system, wherein the DC-DC converter is disposed between the first motor and the transmission; the cooling system includes a cooling pump for cooling the first motor and the second motor;

[0023] The steps for torque control of the engine, the first motor, and the second motor include:

[0024] Limit the engine speed, and control the vehicle to enter the parallel drive mode or the clutch slip control state based on the vehicle speed after the engine speed is limited.

[0025] Adjust the speed of the cooling pump to the maximum, and control the voltage of the low-voltage end of the DC-DC converter to the first preset voltage;

[0026] The control switches the torque of the second motor to the torque of the engine, while simultaneously controlling the torque of the second motor to decrease to 0.

[0027] The power corresponding to the torque of the first motor is controlled to be the power consumed at the low voltage end of the DC-DC converter, so that the current of the power battery is basically 0.

[0028] The actual torque of the first motor is added to the crankshaft torque of the engine as a compensation torque.

[0029] Optionally, when the vehicle speed is greater than a preset threshold, the vehicle is controlled to enter the driving state of the parallel drive mode; wherein, the step of controlling the vehicle to enter the driving state of the parallel drive mode includes: after requesting the vehicle to enter the parallel drive mode, sequentially controlling and adjusting the output shaft speed of the first motor, the engine speed and the clutch speed, and engaging the clutch so that the input shaft speed of the transmission is equivalent to the speed of the second motor;

[0030] When the vehicle speed is less than the preset threshold, the vehicle is requested to enter the clutch slip control state of the parallel drive mode. The clutch slip control state is such that the clutch is not fully engaged so that there is a speed difference between the output shaft of the engine and the transmission.

[0031] Optionally, the vehicle mode also includes an idle mode;

[0032] When the vehicle is in idle mode, torque control is performed on the engine, the first motor, and the second motor;

[0033] When the torque of the second motor is completely unloaded and the output torque of the vehicle is entirely output by the engine, the voltage of the first motor is controlled.

[0034] Optionally, the power system further includes a DC-DC converter and a cooling system, wherein the DC-DC converter is disposed between the first motor and the transmission; the cooling system includes a cooling pump for cooling the first motor and the second motor;

[0035] When the vehicle is in idle mode, the steps for torque control of the engine, the first motor, and the second motor include:

[0036] The speed of the cooling pump is controlled to the maximum, and the voltage at the low-voltage end of the DC-DC converter is controlled to the first preset voltage.

[0037] The control switches the torque of the second motor to the torque of the engine, while simultaneously controlling the torque of the second motor to decrease to 0.

[0038] The power corresponding to the torque of the first motor is controlled to be the power consumed at the low voltage end of the DC-DC converter, so that the current of the power battery is basically 0.

[0039] The actual torque of the first motor is added to the torque of the engine as a compensation torque.

[0040] Optionally, when the torque of the second motor is completely unloaded and the vehicle's output torque is entirely output by the first motor, the step of voltage control of the first motor includes:

[0041] Obtain the open / closed state of the vehicle's battery relay;

[0042] 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 first target voltage and the first actual voltage fed back at the current moment are input into the closed-loop PID controller to calculate the first target torque of the first motor at the current moment.

[0043] The first feedforward torque of the first motor at the previous moment is added to the first target torque to obtain the first actual torque of the first motor at the current moment.

[0044] 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; until the actual voltage of the first motor is within the range of the preset voltage.

[0045] Optionally, after determining whether the fault of the power battery is a voltage control fault based on the fault signal, the method further includes:

[0046] When the fault of the power battery is determined to be the voltage control fault, the system receives the control signal sent by the power battery controller, controls the voltage of the first motor 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.

[0047] In particular, the present invention also provides a control system for the power system of a dual-motor 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 vehicle power system voltage control method described above in the case of a power battery failure.

[0048] In this solution, fault signals from the vehicle's power battery are typically acquired by the power battery controller continuously monitoring various data points of the power battery and sending the detected signals to the vehicle controller. When the power battery controller detects an abnormal voltage in the power battery (higher or lower than the normal output voltage), the vehicle controller, upon receiving this signal, determines that a voltage control fault has occurred in the power battery. The vehicle controller then controls the voltage of the first motor to ensure that the power generation of the first motor and the power consumption of the load are consistent, while maintaining zero current at the battery bus terminal. This design allows the voltage of the vehicle's first motor to fluctuate within a certain range when a voltage fault occurs in the power battery, while ensuring normal vehicle operation. This prevents the voltage from exceeding a threshold and causing serious power system malfunctions, thus improving vehicle safety.

[0049] In this embodiment, when the power battery relay is closed, the first actual torque is calculated using the actual voltage of the first motor at the previous moment as the first target voltage at the current moment. After determining whether the first actual torque is within the preset actual torque range, the set torque is continuously adjusted as the second target torque when the relay is opened to obtain the second actual torque. This process is repeated continuously. When the second 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. This avoids the power generation of the first motor and the power consumption of the load being equal when the vehicle's power battery fails, keeping the current at the battery bus terminal at 0, while the actual voltage of the first motor is maintained within the threshold range of the target voltage.

[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 6 This is a schematic flowchart illustrating the voltage control steps of a first 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 of a control method for the power system of a dual-motor hybrid vehicle according to another specific embodiment of the present invention;

[0060] Figure 9 This is a schematic flowchart illustrating the steps of torque control of an engine, a first motor, and a second motor according to another specific embodiment of the present invention.

[0061] Figure 10This is a schematic flowchart illustrating the voltage control steps for the first motor when the torque of the second motor is completely unloaded and the vehicle's output torque is entirely output by the first motor, according to a specific embodiment of the present invention. Detailed Implementation

[0062] 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.

[0063] Specifically, such as Figure 5 As shown, the powertrain control method for a dual-motor hybrid vehicle in this embodiment may include:

[0064] Step S100: Obtain the fault signal of the vehicle's power battery;

[0065] Step S200: Determine whether the fault of the power battery is a voltage control fault based on the fault signal;

[0066] In step S300, when it is determined that the fault of the power battery is a voltage control fault, the voltage of the first motor is controlled so that the power generation of the first motor and the power consumption of the load are kept consistent, and the current at the power battery bus terminal is kept zero.

[0067] Specifically, in this embodiment, fault signals from the vehicle's power battery are typically acquired by the power battery controller continuously monitoring various data points of the power battery and sending the detected signals to the vehicle controller. When the power battery controller detects an abnormal voltage in the power battery (higher or lower than the normal output voltage), the vehicle controller, upon receiving this signal, can determine that a voltage control fault has occurred in the power battery. The vehicle controller then controls the voltage of the first motor to ensure that the power generation of the first motor and the power consumption of the load remain consistent, while maintaining zero current at the battery bus terminal. This design allows the voltage of the vehicle's first motor to fluctuate within a certain range while ensuring normal vehicle operation when a voltage fault occurs in the power battery of the power system in this embodiment. This prevents the voltage from exceeding a threshold and causing serious power system malfunctions, thereby improving vehicle safety.

[0068] Generally, when the vehicle controller determines that the power battery has a voltage fault based on the received fault signal, it will control the voltage of the first motor and the voltage and charging / discharging power of the power battery simultaneously. Specifically, it will control the voltage of the power battery to fluctuate within a certain range, namely a set voltage threshold. This set voltage threshold can be set according to the situation. At the same time, it will limit the charging / discharging power of the power battery to a preset power threshold range, which can be 7kW. In this way, the voltage and charging / discharging power of the power battery are kept within a certain range, avoiding situations where the power battery overvoltage or excessive charging / discharging power could lead to combustion or even explosion.

[0069] As a specific embodiment of the present invention, such as Figure 6 As shown, in step S300 of this embodiment, voltage control of the first motor may include the following steps:

[0070] Step S301: Obtain the vehicle's drive mode, wherein the drive mode may include pure electric drive mode, series drive mode, and parallel drive mode.

[0071] Step S302: When the vehicle is in pure electric drive mode, series drive mode and parallel drive mode, control the engine to be in the start state and the vehicle to enter the parallel drive mode or the clutch slip control state in the parallel drive mode.

[0072] In step S301, since the vehicle needs to use the power battery as a power source in both pure electric drive mode and series drive mode, and the power battery has already experienced a voltage fault, it is necessary to disconnect the power battery.

[0073] In step S302, when the vehicle is in pure electric drive mode and series drive mode, both drive modes are switched to parallel drive mode. When the vehicle is in parallel drive mode, the drive mode is kept unchanged.

[0074] When the vehicle's drive mode is switched from pure electric drive mode or series drive mode to parallel drive mode, in order to ensure a smooth entry into parallel drive mode, the engine is first requested to start. If the vehicle speed is greater than the minimum speed threshold (20km / h) for entering parallel mode when the engine starts, then the vehicle can directly switch to parallel mode. However, if the vehicle speed is less than the minimum speed threshold when the engine starts, then in order to prevent the vehicle from stalling, the clutch slip control state is requested to enter parallel mode. This ensures that the vehicle enters the parallel state and also ensures that there is a speed difference between the engine and the transmission input shaft.

[0075] Step S303: Perform torque control on the engine, the first motor, and the second motor;

[0076] In step S303, since the vehicle's driving mode has entered the parallel driving mode, if the vehicle switches from the pure electric driving mode or the series driving mode to the parallel driving mode, the output torque of the vehicle's engine, first motor and second motor also needs to be changed accordingly to ensure the normal use and operation of the vehicle.

[0077] In step S304, when the torque of the second motor is completely unloaded and the vehicle's output torque is entirely output by the engine, the voltage of the first motor is controlled.

[0078] In step S304, since the vehicle is driving normally, when the first motor and the second motor switch torque during normal driving, voltage sudden changes or large fluctuations are likely to occur. Therefore, it is necessary to control the voltage of the first motor to prevent the voltage of the first motor from exceeding the preset range, which would cause the vehicle to be unable to move normally.

[0079] As a specific embodiment of the present invention, step S302 of this embodiment, which controls the vehicle to enter the parallel drive mode driving state or the clutch slip control state of the parallel drive mode when the vehicle is in pure electric drive mode, series drive mode, and parallel drive mode, includes:

[0080] When the vehicle is in pure electric drive mode, an engine start request is made. The vehicle's current speed is compared to a preset speed threshold, and the system controls the vehicle to either enter parallel drive mode or the clutch slip control state of parallel drive mode.

[0081] When the vehicle is in series drive mode, keep the engine running, compare the current vehicle speed with the preset vehicle speed threshold, and control the vehicle to enter the drive state of parallel drive mode or the clutch slip control state.

[0082] The preset speed threshold is the minimum speed at which a vehicle can enter parallel drive mode.

[0083] In this embodiment, since the engine is not started when the vehicle is in pure electric drive mode, it is necessary to prioritize requesting the engine to start, and then compare the vehicle speed with a speed threshold to control whether the vehicle enters parallel drive mode or slicker control mode. When the vehicle is in series mode, the engine is already running, so it is necessary to keep the engine running, and then compare the vehicle speed with a speed threshold to control whether the vehicle enters parallel drive mode or the slicker control mode within parallel drive mode.

[0084] As a specific embodiment of the present invention, whether the vehicle enters parallel drive mode or the sliding control state of parallel drive mode depends mainly on the comparison between the vehicle speed and a preset vehicle speed threshold when the engine is running. When the vehicle speed is greater than the preset threshold, the vehicle is controlled to enter the driving state of parallel drive mode. Specifically, the steps of controlling the vehicle to enter the driving state of parallel drive mode include: after requesting the vehicle to enter parallel drive mode, sequentially controlling and adjusting the output shaft speed of the first motor, the engine speed, and the clutch speed, and engaging the clutch so that the input shaft speed of the transmission is comparable to the speed of the second motor. When the vehicle speed is less than the preset threshold, the vehicle is requested to enter the clutch sliding control state of parallel drive mode, wherein the clutch sliding control state of parallel drive mode is such that the clutch is not fully engaged so that there is a speed difference between the output shaft of the engine and the output shaft of the transmission. The purpose of switching the vehicle control to the sliding control state of parallel drive mode is to prevent the engine speed from being too low and causing the engine to stall when entering parallel drive mode.

[0085] As a specific embodiment of the present invention, such as Figure 7 As shown, the power system in this embodiment further includes a DC-DC converter and a cooling system. The DC-DC converter is disposed between the first motor and the transmission. The cooling system includes a cooling pump and is used to cool the first motor and the second motor.

[0086] Step S303 in this embodiment, the step of torque control of the engine, the first motor and the second motor, may include:

[0087] Step S3031: Limit the engine speed and control the vehicle to enter the parallel drive mode or clutch slip control state based on the vehicle speed after the engine speed is limited.

[0088] Step S3032: Adjust the speed of the cooling pump to the maximum and control the voltage of the low-voltage end of the current converter to the first preset voltage (14V).

[0089] In step S3033, the torque of the second motor is exchanged with the torque of the engine, while the torque of the second motor is reduced to 0.

[0090] Step S3034: Control the power corresponding to the torque of the first motor to be the power consumed at the low-voltage end of the current converter, so that the current of the power battery is basically 0.

[0091] In step S3035, the actual torque of the first motor is added to the engine torque as a compensation torque.

[0092] In step S3031, when torque control of the engine, the first motor, and the second motor is required, the engine speed must first be limited, for example, to 3000 rpm. After the engine speed is limited, the vehicle speed is compared with a preset vehicle speed threshold to control whether the vehicle enters parallel mode or the sliding diaphragm control state in parallel mode. This process is the same as the aforementioned control process and will not be described again here.

[0093] In this embodiment, step S303, which involves torque control of the engine, the first motor, and the second motor, refers to the change in torque of the engine, the first motor, and the second motor during the vehicle's transition from other starting modes to parallel mode. This torque change ensures that the output torque of the entire power system remains constant, thus guaranteeing normal vehicle operation and smooth switching of drive modes.

[0094] As a specific embodiment of the present invention, the vehicle mode of this embodiment also includes an idle mode;

[0095] As one embodiment of the present invention, such as Figure 8 As shown, this embodiment may further include:

[0096] Step SS301: Obtain the vehicle's drive mode, where the drive mode may include idle mode;

[0097] Step SS302: When the vehicle is in idle mode, torque control is performed on the engine, the first motor, and the second motor.

[0098] In step SS303, when the torque of the second motor is completely unloaded and the vehicle's output torque is entirely supplied by the output, the voltage of the first motor is controlled.

[0099] As a specific embodiment of the present invention, such as Figure 9As shown, the power system in this embodiment may further include a DC-DC converter and a cooling system. The DC-DC converter is disposed between the first motor and the transmission. The cooling system includes a cooling pump and is used to cool the first motor and the second motor.

[0100] Specifically, step SS302 of this embodiment, which involves torque control of the engine, the first motor, and the second motor when the vehicle is in idle mode, includes:

[0101] Step SS3021: Control the speed of the cooling pump to the maximum and control the voltage of the low-voltage end of the current converter to the first preset voltage (14V).

[0102] Step SS3022: Control the exchange of torque between the second motor and the engine, while simultaneously controlling the torque of the second motor to decrease to 0.

[0103] Step SS3023: Control the power corresponding to the torque of the first motor to be the power consumed at the low voltage end of the current converter, so that the current of the power battery is basically 0.

[0104] Step SS3024: The actual torque of the first motor is added to the crankshaft torque of the engine as a compensation torque.

[0105] In this embodiment, when the vehicle is in idle mode, the difference from the above-mentioned drive mode is that the vehicle has no speed in idle mode, so there is no need to switch the mode to parallel mode. Similarly, when controlling the torque, there is no need to limit the engine speed, and there is no need to switch to parallel mode or diaphragm control state.

[0106] As a specific embodiment of the present invention, such as Figure 10 As shown, step S304 of this embodiment, when the torque of the second motor is completely unloaded and the vehicle's output torque is entirely output by the first motor, includes the following steps for voltage control of the first motor:

[0107] Step S3041: Obtain the open / closed state of the vehicle's battery relay. The battery relay switches between open and closed at preset intervals.

[0108] Step S3042: 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 first target voltage and the first actual voltage fed back at the current moment are input into the closed-loop PID controller to calculate the first target torque of the first motor at the current moment.

[0109] Step S3043: Add the first feedforward torque of the first motor at the previous moment to the first target torque to obtain the first actual torque of the first motor at the current moment.

[0110] Step S3044: 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 as described above.

[0111] Step S3045: Repeat the above steps until the actual voltage of the first motor is within the preset voltage range.

[0112] Specifically, in step S3044 of this embodiment, the second actual torque of the first motor is obtained by using the set voltage as the second target voltage and following the same calculation method as the first actual torque. This specifically includes using the set voltage as the second target voltage, inputting the second target voltage and the second actual voltage fed back at the current moment into the closed-loop PID controller, thereby calculating the second target torque of the first motor at the current moment.

[0113] Specifically, because the set voltage is adjusted, the output second actual torque will not be exactly the same as the first actual torque. When the second 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, which avoids the power generation of the first motor and the power consumption of the load being equal when the vehicle's power battery fails, keeping the current at the battery bus terminal at 0, while the actual voltage of the first motor is maintained within the threshold range of the target voltage.

[0114] After step S3044, when the value of the first actual torque calculated from the first motor's actual voltage at the previous moment as the first target voltage at the current moment is not within the preset actual torque range, an alarm is triggered to inform the driver or maintenance personnel of the fault.

[0115] As a specific embodiment of the present invention, this embodiment also provides a powertrain control system for a dual-motor 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 dual-motor 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).

[0116] 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 dual-motor hybrid vehicle described above.

[0117] 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 dual-motor hybrid vehicle, characterized in that, The vehicle's power system includes a power battery, an engine, a first motor, a second motor, a clutch, a transmission, a DC-DC converter, and a cooling system. The engine is connected to the first motor, the first motor is connected to the clutch and then to the transmission, the second motor is directly connected to the transmission, and the DC-DC converter is located between the first motor and the transmission. The cooling system includes a cooling pump and is used to cool the first motor and the second motor. The power system control method includes: Obtain fault signals from the vehicle's power battery; Determine whether the fault of the power battery is a voltage control fault based on the fault signal; When the fault of the power battery is determined to be the voltage control fault, the voltage of the first motor is controlled so that the power generation of the first motor and the power consumption of the load are kept consistent, and the current at the power battery bus terminal is kept to zero. When the vehicle is in idle mode, torque control is performed on the engine, the first motor, and the second motor, including: controlling the speed of the cooling pump to the maximum and controlling the voltage of the low-voltage end of the DC-DC converter to a first preset voltage; controlling the exchange of the torque of the second motor with the torque of the engine, while controlling the torque of the second motor to drop to 0; controlling the power corresponding to the torque of the first motor to be the power consumed by the low-voltage end of the DC-DC converter, so that the current of the power battery is 0; and adding the actual torque of the first motor as a compensation torque to the torque of the engine.

2. The power system control method for a dual-motor hybrid vehicle according to claim 1, characterized in that, The voltage control of the first motor includes the following steps: The driving mode of the vehicle is obtained, wherein the driving mode includes pure electric driving mode, series driving mode and parallel driving mode; When the vehicle is in the pure electric drive mode, series drive mode and parallel drive mode, the engine is controlled to be in the starting state and the vehicle enters the parallel drive mode or the clutch slip control state. Torque control is performed on the engine, the first motor, and the second motor; When the torque of the second motor is completely unloaded and the output torque of the vehicle is entirely output by the engine, the voltage of the first motor is controlled.

3. The power system control method for a dual-motor hybrid vehicle according to claim 2, characterized in that, When the vehicle is in the pure electric drive mode, series drive mode, and parallel drive mode, the step of controlling the vehicle to enter the parallel drive mode drive state or the clutch slip control state of the parallel drive mode includes: When the vehicle is in the pure electric drive mode, the engine is requested to start. Based on a comparison between the vehicle's current speed and a preset speed threshold, the vehicle is controlled to enter either the parallel drive mode or the clutch slip control state. When the vehicle is in the series drive mode, the engine is kept running, and the vehicle is controlled to enter the drive state of the parallel drive mode or the clutch slip control state by comparing the current vehicle speed with the preset vehicle speed threshold. The preset speed threshold is the minimum speed at which the vehicle can enter the parallel drive mode.

4. The power system control method for a dual-motor hybrid vehicle according to claim 3, characterized in that, The steps for torque control of the engine, the first motor, and the second motor include: Limit the engine speed, and control the vehicle to enter the parallel drive mode or the clutch slip control state based on the vehicle speed after the engine speed is limited. Adjust the speed of the cooling pump to the maximum, and control the voltage of the low-voltage end of the DC-DC converter to the first preset voltage; The control switches the torque of the second motor to the torque of the engine, while simultaneously controlling the torque of the second motor to decrease to 0. The charging power corresponding to the torque of the first motor is controlled to be the power consumed at the low voltage end of the DC-DC converter, so that the current of the power battery is basically 0. The actual torque of the first motor is added to the torque of the engine as a compensation torque.

5. The power system control method for a dual-motor hybrid vehicle according to claim 3 or 4, characterized in that, When the vehicle speed exceeds a preset threshold, the vehicle is controlled to enter the parallel drive mode. The step of controlling the vehicle to enter the parallel drive mode includes: after requesting the vehicle to enter the parallel drive mode, the output shaft speed of the first motor, the engine speed, and the clutch speed are sequentially controlled and adjusted, and the clutch is engaged so that the input shaft speed of the transmission is equivalent to the speed of the second motor. When the vehicle speed is less than the preset threshold, the vehicle is requested to enter the clutch slip control state. The clutch slip control state of the parallel drive mode is that the clutch is not fully engaged so that there is a speed difference between the output shaft of the engine and the transmission.

6. The power system control method for a dual-motor hybrid vehicle according to claim 1, characterized in that, When the vehicle is in idle mode, the torque of the second motor is completely unloaded, and the output torque of the vehicle is entirely output by the engine, the voltage of the first motor is controlled.

7. The power system control method for a dual-motor hybrid vehicle according to any one of claims 2-4 and 6, characterized in that, When the torque of the second motor is completely unloaded and the vehicle's output torque is entirely supplied by the engine, the steps for voltage control 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 first target voltage and the first actual voltage fed back at the current moment are input into the closed-loop PID controller to calculate the first target torque of the first motor at the current moment. The first feedforward torque of the first motor at the previous moment is added to the first target torque to obtain the first actual torque of the first motor at the current moment. 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. Until the actual voltage of the first motor is within the preset voltage range.

8. The power system control method for a dual-motor hybrid vehicle according to claim 7, characterized in that, After determining whether the fault of the power battery is a voltage control fault based on the fault signal, the process further includes: When the fault of the power battery is determined to be a voltage control fault, the system receives a control signal sent by the power battery controller and controls the voltage of the first motor to be within a preset voltage threshold range.

9. A control system for the power system of a dual-motor 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 dual-motor hybrid vehicle according to any one of claims 1-8.

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