Control Method, Device, Medium and Electric Vehicle of Electric Drive System

Abstract

The embodiments of the present application disclose a control method, device, medium and electric vehicle for an electric drive system, relating to the technical field of power control. The method includes: obtaining the ambient temperature and the motor stator temperature; determining the motor thermal management state of the electric drive system according to the ambient temperature and the motor stator temperature, where the motor thermal management state is used to represent the state of the motor affected by temperature; adjusting the operating mode of the powertrain of the electric drive system according to the motor thermal management state, where the operating mode of the powertrain is used to represent the driving method of the electric drive system; adjusting the torque distribution method of the electric drive system according to the ambient temperature and the motor stator temperature. This method can limit the temperature rise of the motor on the premise of meeting the driving requirements.

Description

Technical Field

[0001] The present application relates to the technical field of power control, and particularly to a control method, device, medium and electric vehicle for an electric drive system. Background Art

[0002] Hybrid electric vehicles generally have three power-train operation modes: pure electric, series and parallel; after years of development, the control strategies for power-train operation modes and torque distribution are basically mature.

[0003] In the related art, when the engine is not working, it can be driven by the main motor or the auxiliary motor alone, which is called the single-motor electric drive mode; and when it is driven by the main motor and the auxiliary motor together, it is called the dual-motor electric drive mode; both belong to the pure electric mode. When using the single-motor electric drive mode, the torque is distributed to the only motor in gear; when using the dual-motor electric drive mode, the torque is preferentially distributed to the main motor.

[0004] However, in the related art, there may be a problem of motor overheating when the environmental temperature is high or the working load is heavy under the torque distribution method. Summary of the Invention

[0005] Embodiments of the present application provide a control method, device, medium and electric vehicle for an electric drive system. The method can adjust the working power of the motor by reasonably distributing torque to the motor, thereby reducing the motor temperature. The technical solution includes:

[0006] According to one aspect of the present application, there is provided a control method for an electric drive system, the method including:

[0007] Obtain the environmental temperature and the motor stator temperature;

[0008] Determine the motor thermal management state of the electric drive system according to the environmental temperature and the motor stator temperature, where the motor thermal management state is used to represent the state generated by the motor affected by temperature;

[0009] Adjust the power-train operation mode of the electric drive system according to the motor thermal management state, where the power-train operation mode is used to represent the driving mode of the electric drive system;

[0010] Adjust the torque distribution method of the electric drive system according to the environmental temperature and the motor stator temperature.

[0011] According to another aspect of the present application, there is provided a control device for an electric drive system, the device including:

[0012] An input module, configured to obtain the environmental temperature and the motor stator temperature;

[0013] A thermal management module, configured to determine the motor thermal management state of the electric drive system according to the ambient temperature and the motor stator temperature, where the motor thermal management state is used to represent the state of the motor affected by temperature;

[0014] A powertrain coordination module, configured to adjust the powertrain operation mode of the electric drive system according to the motor thermal management state, where the powertrain operation mode is used to represent the driving mode of the electric drive system;

[0015] A torque distribution module, configured to adjust the torque distribution mode of the electric drive system according to the ambient temperature and the motor stator temperature.

[0016] According to another aspect of the present application, an electric vehicle is provided, which includes: a processor and a memory. At least one instruction, at least one program, a code set or an instruction set is stored in the memory, and the at least one instruction, at least one program, the code set or the instruction set is loaded and executed by the processor to implement the control method of the electric drive system in the above aspect.

[0017] According to another aspect of the present application, a computer storage medium is provided. At least one program code is stored in the computer-readable storage medium, and the program code is loaded and executed by the processor to implement the control method of the electric drive system in the above aspect.

[0018] According to another aspect of the present application, a computer program product or a computer program is provided. The above computer program product or computer program includes computer instructions, and the above computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the above computer instructions from the above computer-readable storage medium, and the processor executes the above computer instructions, so that the above computer device executes the control method of the electric drive system in the above aspect.

[0019] The beneficial effects brought by the technical solutions provided in the embodiments of the present application at least include:

[0020] Adjust the powertrain operation mode of the electric drive system according to the motor thermal management state, and adjust the torque distribution mode of the electric drive system according to the ambient temperature and the motor stator temperature, so that on the premise of meeting the driving requirements, by reasonably controlling the operation mode of the electric drive system and the torque distribution modes of different motors, the temperature rise of the motor is restricted, thereby improving the driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 shows a schematic structural diagram of a hybrid vehicle provided by an embodiment of the present application;

[0023] Figure 2 shows a schematic flow diagram of a control method for an electric drive system provided by an embodiment of the present application;

[0024] Figure 3 shows a schematic flow diagram of a method for judging the state of an electric drive system provided by an embodiment of the present application;

[0025] Figure 4 shows a schematic flow diagram of a method for determining a control strategy of an electric drive system provided by an embodiment of the present application;

[0026] Figure 5 shows a schematic flow diagram of a torque distribution method for an electric drive system provided by an embodiment of the present application;

[0027] Figure 6 shows a schematic structural diagram of a control device for an electric drive system provided by an embodiment of the present application;

[0028] Figure 7 shows a schematic structural diagram of a hybrid control unit provided by an embodiment of the present application. Detailed Embodiments

[0029] To make the objectives, technical solutions, and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the accompanying drawings.

[0030] First, introduce the nouns involved in the embodiments of the present application:

[0031] Hybrid vehicle: refers to a hybrid electric vehicle (HEV), that is, an internal combustion engine (diesel engine or gasoline engine) and an electric motor are used as power sources. The hybrid vehicle includes at least one of a series hybrid vehicle, a parallel hybrid vehicle, and a series-parallel hybrid vehicle.

[0032] It should be noted that before and during the collection of relevant user data in this application, a prompt interface, a pop-up window, or a voice prompt message can be displayed. The prompt interface, pop-up window, or voice prompt message is used to prompt the user that their relevant data is currently being collected, so that this application only starts to execute the relevant steps for obtaining the user's relevant data after obtaining the user's confirmation operation on the prompt interface or the pop-up window. Otherwise (that is, when the user's confirmation operation on the prompt interface or the pop-up window is not obtained), the relevant steps for obtaining the user's relevant data are ended, that is, the user's relevant data is not obtained. In other words, all user data collected in this application is collected with the user's consent and authorization, and the collection, use, and processing of relevant user data need to comply with relevant laws, regulations, and standards in relevant countries and regions.

[0033] Figure 1 Fig. shows a schematic structural diagram of a hybrid vehicle provided by an embodiment of the present application. The hybrid vehicle includes a hybrid control unit 101, an engine 102, a main motor 103, and an auxiliary motor 104.

[0034] The hybrid control unit 101 is used to control the operation mode of the hybrid vehicle and the torque distribution mode of the power source.

[0035] The engine 102 is used to provide power for the hybrid vehicle. In the embodiment of the present application, the engine 102 is an internal combustion engine that converts the chemical energy of fuel into mechanical energy of piston movement and outputs power externally.

[0036] The main motor 103 and the auxiliary motor 104 constitute the electric drive system of the hybrid vehicle. The main motor 103 and the auxiliary motor 104 adjust the operation mode of the power assembly and the torque distribution mode according to the instructions of the hybrid control unit 101.

[0037] Figure 2 Fig. shows a schematic flow diagram of a control method for an electric drive system provided by an embodiment of the present application.

[0038] The method includes:

[0039] Step 202: Obtain the ambient temperature and the motor stator temperature.

[0040] Optionally, the ambient temperature is obtained through a temperature sensor, or the ambient temperature is obtained through a weather forecast app (application).

[0041] Optionally, the hybrid vehicle includes a main motor and an auxiliary motor. The motor stator temperature refers to the temperatures of both the main motor and the auxiliary motor, and the motor stator temperature can be obtained through a temperature sensor.

[0042] Step 204: Determine the motor thermal management status of the electric drive system according to the ambient temperature and the motor stator temperature. The motor thermal management status is used to represent the status of the motor affected by temperature.

[0043] Determine the thermal failure type of the motor of the electric drive system according to the motor stator temperature. The thermal failure type includes a thermally failed motor and a thermally limited motor; determine the status of the electric drive system according to the thermal failure type. Among them, the status of the electric drive system includes at least one of a failure status, a semi-failure status, a thermal protection status, and a normal temperature status.

[0044] Optionally, when the motor stator temperature is higher than the upper limit of the failure temperature, or when the motor torque capacity is lower than the product of the lower limit of the failure torque percentage and the maximum torque capacity, it is determined that the motor of the electric drive system is a thermally failed motor. Among them, the upper limit of the failure temperature and the lower limit of the failure torque percentage can be preset by technicians. In some other embodiments, the upper limit of the failure temperature, the lower limit of the failure torque percentage are related to the motor usage duration. For example, the upper limit of the failure temperature is negatively correlated with the motor usage duration, and the lower limit of the failure torque percentage is negatively correlated with the motor usage duration.

[0045] Optionally, when the motor stator temperature is higher than the upper limit of the temperature warning, it is determined that the motor of the electric drive system is a thermally limited motor.

[0046] 1. When all the motors of the electric drive system are thermally failed motors, it is determined that the electric drive system is in a failure status. In some embodiments, the electric drive system includes a main motor and a negative motor, and both the main motor and the auxiliary motor are thermally failed motors.

[0047] 2. When one motor of the electric drive system is a thermally failed motor, it is determined that the electric drive system is in a semi-failure status. In some embodiments, if only the main motor is a thermally failed motor, or only the auxiliary motor is a thermally failed motor, then the electric drive system is in a semi-failure status.

[0048] 3. When all the motors of the electric drive system are not thermally failed motors and at least one motor is a thermally limited motor, or when the ambient temperature is higher than the upper limit of the ambient high temperature and the transmission oil temperature exceeds the upper limit of the transmission high temperature, it is determined that the electric drive system is in a thermal protection status. Exemplarily, when the electric drive system is not in a failure status or a semi-failure status, there is 1 or 2 thermally limited motors in the electric drive system, or when the ambient temperature is higher than the upper limit of the ambient high temperature and the transmission oil temperature exceeds the upper limit of the transmission high temperature, then the electric drive system is in a thermal protection status.

[0049] 4. When the electric drive system is not in a failure status, a semi-failure status, and a thermal protection status, it is determined that the electric drive system is in a normal temperature status.

[0050] Step 206: Adjust the operating mode of the powertrain of the electric drive system according to the motor thermal management status, where the powertrain operating mode is used to represent the driving method of the electric drive system.

[0051] Optionally, when the motor thermal management status is the normal temperature state, it indicates that the motor temperature is normal and there is no need to adjust the operating mode of the powertrain of the electric drive system. Therefore, when the motor thermal management status is the normal temperature state, keep the operating mode of the powertrain of the electric drive system unchanged.

[0052] Optionally, when the motor thermal management status is the thermal protection state, it indicates that there is a motor in the electric drive system that is a thermally failed motor and its temperature is too high. To lower the temperature of this motor, other motors can be turned on, thereby reducing the workload of the aforementioned motor and achieving the effect of reducing the motor temperature. When the motor thermal management status is the thermal protection state, adjust the operating mode of the powertrain of the electric drive system to the dual-motor electric drive mode.

[0053] Optionally, when the motor thermal management status is the failure state, all motors in the electric drive system have the phenomenon of too high temperature. If the motors continue to work, it will pose a safety hazard, so it is necessary to turn off all motors of the electric drive system in a timely manner. Therefore, when the motor thermal management status is the failure state, disable the dual-motor electric drive mode.

[0054] Optionally, when the motor thermal management status is the semi-failure state, if the vehicle speed is lower than the lower limit of the parallel allowable vehicle speed, adjust the operating mode of the powertrain of the electric drive system to the dual-motor electric drive mode; if the vehicle speed is higher than the lower limit of the parallel allowable vehicle speed, adjust the operating mode of the powertrain of the electric drive system to the parallel mode. Optionally, in the semi-failure state, disable the series mode in the powertrain operating mode. The reason for disabling the series mode is that if the failed motor is the main motor, the series mode will cause the electric drive system to lose its driving ability; and if the failed motor is the auxiliary motor, the series mode will cause the electric drive system to lose its power generation ability, and both of the above situations will seriously affect the normal operation of the vehicle.

[0055] Step 208: Adjust the torque distribution method of the electric drive system according to the ambient temperature and the motor stator temperature.

[0056] Optionally, determine the maximum torque of the motor according to the ambient temperature, the motor stator temperature, and the motor peak torque; determine the torque distribution method of the electric drive system through the maximum torque of the motor.

[0057] Optionally, when the system demand torque is less than the maximum torque of the low-temperature motor, distribute the system demand torque to the low-temperature motor.

[0058] Optionally, when the system demand torque is greater than the sum of the maximum torque capabilities of the low-temperature motor and the high-temperature motor, control the low-temperature motor and the high-temperature motor to adopt the maximum torque capability;

[0059] Optionally, when the system required torque is greater than the maximum torque capacity of the low-temperature motor and less than the sum of the maximum torque capacities of the low-temperature motor and the high-temperature motor, control the low-temperature motor to adopt the maximum torque capacity, and control the high-temperature motor to supplement the interpolation of the system required torque and the maximum torque capacity.

[0060] In summary, in this embodiment, the powertrain operation mode of the electric drive system is adjusted according to the motor thermal management state, and the torque distribution mode of the electric drive system is adjusted according to the ambient temperature and the motor stator temperature, so that on the premise of meeting the driving requirements, by reasonably controlling the operation mode of the electric drive system and the torque distribution modes of different motors, the temperature rise of the motors is restricted, thereby improving the driving safety.

[0061] Figure 3 The flowchart of a method for judging the state of an electric drive system provided by an embodiment of the present application is shown. The method includes:

[0062] Step 301: Judge whether both the main and auxiliary motors fail.

[0063] If both the main and auxiliary motors fail, execute step 302;

[0064] If both the main and auxiliary motors do not fail, execute step 303.

[0065] Optionally, when the motor stator temperature is higher than the upper limit of the failure temperature, or the motor torque capacity is lower than the product of the lower limit of the failure torque percentage and the maximum torque capacity, determine that the motor of the electric drive system is a thermally failed motor.

[0066] Optionally, the lower limit of the failure torque percentage includes the lower limit of the main motor failure torque percentage and the lower limit of the auxiliary motor failure torque percentage. The lower limit of the main motor failure torque percentage and the lower limit of the auxiliary motor failure torque percentage may be the same or different.

[0067] Step 302: Determine that the electric drive system is in a failure state.

[0068] Step 303: Judge whether only one motor fails.

[0069] If only one motor fails, execute step 304;

[0070] If no motor fails, execute step 305.

[0071] Step 304: Determine that the electric drive system is in a semi-failure state.

[0072] Step 305: Judge whether there is a thermally limited motor.

[0073] If there is a thermally limited motor, execute step 306;

[0074] If there is no motor with thermal limit, step 307 is executed.

[0075] Optionally, when the temperature of the motor stator is higher than the upper limit of temperature warning, it is determined that the motor of the electric drive system is a motor with thermal limit. Herein, the upper limit of temperature warning is less than the upper limit of failure temperature.

[0076] Step 306: Determine that the electric drive system is in a thermal protection state.

[0077] In some other embodiments, when the ambient temperature is higher than the upper limit of ambient high temperature and the transmission oil temperature exceeds the upper limit of transmission high temperature, it is determined that the electric drive system is in a thermal protection state.

[0078] Step 307: Determine that the electric drive system is in a normal temperature state.

[0079] In summary, this embodiment provides a method for identifying the thermal management state of an electric drive system, which can identify the states and temperatures of the motors in the electric drive system for subsequent powertrain coordination and torque distribution, and prevent the motors in the electric drive system from having too high temperature or abnormal operation.

[0080] Figure 4 The flow diagram of a method for determining the control strategy of an electric drive system provided by an embodiment of the present application is shown. The method includes:

[0081] Step 401: Determine whether the electric drive system is in a normal temperature state.

[0082] If the electric drive system is in a normal temperature state, step 402 is executed;

[0083] If the electric drive system is not in a normal temperature state, step 403 is executed.

[0084] Step 402: Do not adjust the operating mode of the powertrain.

[0085] When the electric drive system is in a normal temperature state,

[0086] Step 403: Determine whether the electric drive system is in a thermal protection state.

[0087] If the electric drive system is in a thermal protection state, step 404 is executed;

[0088] If the electric drive system is not in a thermal protection state, step 405 is executed.

[0089] Step 404: Adopt a thermal protection adjustment strategy.

[0090] Optionally, when the electric drive system is in a thermal protection state, if the target of the original powertrain operating mode is a single-motor electric drive mode, it is adjusted to a dual-motor electric drive mode.

[0091] Step 405: Determine whether the electric drive system is in a semi-failure state.

[0092] If the electric drive system is in a semi-failure state, then execute Step 406;

[0093] If the electric drive system is not in a semi-failure state, then execute Step 407.

[0094] Step 406: Adopt a semi-failure mode adjustment strategy.

[0095] Optionally, set the powertrain operation mode to the parallel mode.

[0096] Optionally, disable the series mode. The reason for disabling the series mode is that if the failed motor is the main motor, the series mode will lose its driving ability; and if the failed motor is the auxiliary motor, the series mode will lose its power generation ability.

[0097] Step 407: Adopt a failure mode adjustment strategy.

[0098] Optionally, the powertrain operation mode further disables the dual-motor electric drive mode to avoid damaging the electric drive system.

[0099] In summary, the embodiments of the present application provide a method for determining the powertrain operation mode. This method can control the operation modes of different motors in a hybrid vehicle, provide the working modes of the motors at different temperatures, help reduce the working temperature of the motors, and improve the driving safety.

[0100] The embodiments of the present application suppress the motor temperature rise through torque distribution. If the motor torque is not restricted enough, the effect of suppressing the temperature rise cannot be achieved; while if the motor torque is overly restricted, the power performance will be affected. Therefore, it is very important to determine the maximum torque capacity of the motor under the current working conditions.

[0101] The motor stator temperature is an important motor thermal performance characteristic value, and too high ambient temperature and transmission oil temperature will accelerate the trend of motor temperature rise; therefore, the correction offset value can be obtained by looking up a table according to the ambient temperature and transmission oil temperature. The sum of this correction offset value and the motor stator temperature is the corrected motor stator temperature. When the corrected motor stator temperature is lower than the temperature warning upper limit, the motor maximum torque is determined to be the motor peak torque; when the corrected motor stator temperature is higher than the failure temperature upper limit, the motor maximum torque is determined to be zero; when the corrected motor stator temperature is lower than the failure temperature upper limit and higher than the temperature warning upper limit, the motor maximum torque is determined to be the linear interpolation between the motor peak torque and zero.

[0102] Figure 5 The flow diagram of a torque distribution method for an electric drive system provided by the embodiments of the present application is shown. This method includes:

[0103] Step 501: Determine whether the system required torque is less than the maximum torque capacity of the low-temperature motor.

[0104] If the system required torque is less than the maximum torque capacity of the low-temperature motor, then execute Step 502;

[0105] If the system required torque is greater than the maximum torque capacity of the low-temperature motor, then execute Step 503.

[0106] Step 502: The low-temperature motor undertakes the required torque and the high-temperature motor is idle.

[0107] In this case, the system required torque of the electric drive system is all borne by the low-temperature motor; at this time, the working load of the high-temperature motor is 0, and the motor can achieve rapid cooling with the help of the cooling system.

[0108] Step 503: Determine whether the system required torque is greater than the maximum torque capacity of the dual motors.

[0109] If the system required torque is greater than the maximum torque capacity of the dual motors, then execute Step 504;

[0110] If the system required torque is less than the maximum torque capacity of the dual motors, then execute Step 505.

[0111] Step 504: Both dual motors use the maximum torque.

[0112] Step 505: The low-temperature motor undertakes the maximum torque and the high-temperature motor undertakes the remaining part.

[0113] In this case, the low-temperature motor will exert its maximum torque capacity, while the high-temperature motor only supplements the remaining part; actually, the working load of the high-temperature motor will be lower than that of the low-temperature motor, so it helps to slow down the temperature rise of the high-temperature motor.

[0114] In some embodiments, if the hybrid vehicle adopts a parallel mode: the system required torque is preferentially allocated to the engine; if the system required torque exceeds the engine capacity, the remaining part is the required torque of the electric drive system. The torque distribution strategy between the two motors in the electric drive system is the same as the torque distribution strategy of the dual-motor electric drive mode in the above thermal protection state. Since the system required torque is first allocated to the engine and then to the electric drive system, the overall working load of the electric drive system becomes smaller, which is more conducive to motor cooling. On the other hand, the torque distribution strategies of the single-motor electric drive mode and the series mode are not affected.

[0115] In summary, the embodiment of the present application provides a torque distribution method for an electric drive system. This method can allocate torque to the main and auxiliary motors based on the system required torque, so that on the premise of meeting the system required torque, the respective loads of the main and auxiliary motors will not exceed the maximum torque capacity, and it can also meet the temperature limit requirements of the motors to ensure driving safety.

[0116] Figure 6 The figure shows a schematic structural diagram of a control device for an electric drive system provided by an exemplary embodiment of the present application. This system can be implemented as all or part of a computer device through software, hardware, or a combination of both. The device 600 includes:

[0117] An input module 601, configured to obtain the ambient temperature and the motor stator temperature;

[0118] A thermal management module 602, configured to determine the motor thermal management state of the electric drive system according to the ambient temperature and the motor stator temperature, and the motor thermal management state is used to represent the state generated by the motor affected by temperature;

[0119] A powertrain coordination module 603, configured to adjust the powertrain operation mode of the electric drive system according to the motor thermal management state, and the powertrain operation mode is used to represent the driving method of the electric drive system;

[0120] A torque distribution module 604, configured to adjust the torque distribution method of the electric drive system according to the ambient temperature and the motor stator temperature.

[0121] In an alternative design, the thermal management module 602 is further configured to determine the thermal failure type of the motor of the electric drive system according to the motor stator temperature, and the thermal failure type includes a thermally failed motor and a thermally limited motor; when all the motors of the electric drive system are the thermally failed motors, it is determined that the electric drive system is in a failure state; when one motor of the electric drive system is the thermally failed motor, it is determined that the electric drive system is in a semi-failure state; when all the motors of the electric drive system are not the thermally failed motors and at least one motor is a thermally limited motor, or, when the ambient temperature is higher than the ambient high temperature upper limit and the transmission oil temperature exceeds the transmission high temperature upper limit, it is determined that the electric drive system is in a thermal protection state; when the electric drive system is not in the failure state, the semi-failure state, and the thermal protection state, it is determined that the electric drive system is in a normal temperature state.

[0122] In an alternative design, the thermal management module 602 is further configured to determine that the motor of the electric drive system is the thermally failed motor when the motor stator temperature is higher than the failure temperature upper limit, or when the motor torque capacity is lower than the product of the failure torque percentage lower limit and the maximum torque capacity; when the motor stator temperature is higher than the temperature warning upper limit, it is determined that the motor of the electric drive system is the thermally limited motor.

[0123] In an alternative design, the powertrain coordination module 603 is further configured to keep the powertrain operation mode of the electric drive system unchanged when the motor thermal management state is a normal temperature state; adjust the powertrain operation mode of the electric drive system to a dual-motor electric drive mode when the motor thermal management state is a thermal protection state; disable the dual-motor electric drive mode when the motor thermal management state is a failure state; and if the vehicle speed is lower than the lower limit of the parallel operation allowable speed, adjust the powertrain operation mode of the electric drive system to the dual-motor electric drive mode when the motor thermal management state is a semi-failure state; and if the vehicle speed is higher than the lower limit of the parallel operation allowable speed, adjust the powertrain operation mode of the electric drive system to a parallel mode.

[0124] In an alternative design, the electric drive system includes a low-temperature motor and a high-temperature motor; the electric drive system adopts a dual-motor electric drive mode; the torque distribution module 604 is further configured to determine the maximum motor torque according to the ambient temperature, the motor stator temperature, and the motor peak torque; distribute the system demand torque to the low-temperature motor when the system demand torque is less than the maximum motor torque of the low-temperature motor; control the low-temperature motor and the high-temperature motor to adopt the maximum torque capacity when the system demand torque is greater than the sum of the maximum torque capacities of the low-temperature motor and the high-temperature motor; and control the low-temperature motor to adopt the maximum torque capacity and control the high-temperature motor to supplement the interpolation between the system demand torque and the maximum torque capacity when the system demand torque is greater than the maximum torque capacity of the low-temperature motor and less than the sum of the maximum torque capacities of the low-temperature motor and the high-temperature motor.

[0125] In an alternative design, the torque distribution module 604 is further configured to determine a correction bias value according to the ambient temperature and the transmission oil temperature; calculate the sum of the correction bias value and the motor stator temperature to obtain a corrected motor stator temperature; determine the motor maximum torque as the motor peak torque when the corrected motor stator temperature is lower than the temperature warning upper limit; determine the motor maximum torque as zero when the corrected motor stator temperature is higher than the failure temperature upper limit; and determine the motor maximum torque as a linear interpolation between the motor peak torque and zero when the corrected motor stator temperature is lower than the failure temperature upper limit and higher than the temperature warning upper limit.

[0126] In summary, in this embodiment, the powertrain operation mode of the electric drive system is adjusted according to the motor thermal management state, and the torque distribution method of the electric drive system is adjusted according to the ambient temperature and the motor stator temperature, so that on the premise of meeting the driving requirements, by reasonably controlling the operation mode of the electric drive system and the torque distribution methods of different motors, the temperature rise of the motor is restricted, thereby improving the driving safety.

[0127] Figure 7 It is a schematic structural diagram of a hybrid control unit shown according to an exemplary embodiment. The hybrid control unit 700 includes a Central Processing Unit (CPU) 701, a system memory 704 including a Random Access Memory (RAM) 702 and a Read-Only Memory (ROM) 703, and a system bus 705 connecting the system memory 704 and the central processing unit 701. The hybrid control unit 700 also includes a Basic Input / Output System (Input / Output, I / O system) 706 for facilitating the transfer of information between various components within the computer device, and a mass storage device 707 for storing an operating system 713, application programs 714, and other program modules 715.

[0128] The Basic Input / Output System 706 includes a display 708 for displaying information and input devices 709 such as a mouse and a keyboard for user input of information. Both the display 708 and the input devices 709 are connected to the central processing unit 701 through an input / output controller 710 connected to the system bus 705. The Basic Input / Output System 706 may also include an input / output controller 710 for receiving and processing inputs from multiple other devices such as a keyboard, a mouse, or an electronic stylus. Similarly, the input / output controller 710 also provides output to a display screen, a printer, or other types of output devices.

[0129] The mass storage device 707 is connected to the central processing unit 701 through a mass storage controller (not shown) connected to the system bus 705. The mass storage device 707 and its associated computer device-readable medium provide non-volatile storage for the hybrid control unit 700. That is to say, the mass storage device 707 may include computer device-readable media (not shown) such as a hard disk or a Compact Disc Read-Only Memory (CD-ROM) drive.

[0130] Without loss of generality, the computer device-readable medium may include a computer device storage medium and a communication medium. The computer device storage medium includes volatile and non-volatile, removable and non-removable media implemented by any method or technology for storing information such as computer device-readable instructions, data structures, program modules, or other data. The computer device storage medium includes RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), CD-ROM, digital video disc (DVD), or other optical storage, magnetic tape cartridges, tapes, disk storage, or other magnetic storage devices. Of course, those skilled in the art will know that the computer device storage medium is not limited to the above several types. The above system memory 704 and mass storage device 707 can be collectively referred to as memory.

[0131] According to various embodiments of the present disclosure, the hybrid control unit 700 may also operate by connecting to a remote computer device on a network such as the Internet. That is, the hybrid control unit 700 may be connected to the network 711 through the network interface unit 712 connected to the system bus 705, or in other words, the network interface unit 712 may also be used to connect to other types of networks or remote computer device systems (not shown).

[0132] The memory also includes one or more programs. The one or more programs are stored in the memory, and the central processing unit 701 implements all or part of the steps of the above control method for the electric drive system by executing the one or more programs.

[0133] The present application also provides a computer-readable storage medium storing at least one instruction, at least one segment of a program, a code set, or an instruction set. The at least one instruction, at least one segment of the program, the code set, or the instruction set is loaded and executed by a processor to implement the control method for the electric drive system provided in the above method embodiments.

[0134] The present application also provides a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, causing the computer device to execute the control method for the electric drive system provided in the above aspect embodiments.

[0135] The serial numbers of the embodiments of the present application above are only for description and do not represent the superiority or inferiority of the embodiments.

[0136] Those of ordinary skill in the art can understand that all or part of the steps to implement the above embodiments can be completed by hardware, or can be completed by instructing relevant hardware through a program. The program can be stored in a computer-readable storage medium. The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disc, etc.

[0137] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A control method for an electric drive system, characterized in that The electric drive system includes a low-temperature motor and a high-temperature motor; the electric drive system adopts a dual-motor electric drive mode; the method includes: Obtain the ambient temperature and the stator temperature of the motor. Determine the thermal failure type of the motor of the electric drive system according to the stator temperature of the motor, where the thermal failure type includes a thermally failed motor and a thermally limited motor. When all the motors of the electric drive system are the thermally failed motors, determine that the electric drive system is in a failed state; when one motor of the electric drive system is the thermally failed motor, determine that the electric drive system is in a semi-failed state; when all the motors of the electric drive system are not the thermally failed motors and at least one motor is a thermally limited motor, or when the ambient temperature is higher than the ambient high-temperature upper limit and the transmission oil temperature exceeds the transmission high-temperature upper limit, determine that the electric drive system is in a thermal protection state; when the electric drive system is not in the failed state, the semi-failed state, and the thermal protection state, determine that the electric drive system is in a normal temperature state; the failed state, the semi-failed state, the thermal protection state, and the normal temperature state are all motor thermal management states. Adjust the operating mode of the powertrain of the electric drive system according to the motor thermal management state, where the powertrain operating mode is used to represent the driving method of the electric drive system. Determine the correction offset value according to the ambient temperature and the transmission oil temperature. Calculate the sum of the correction offset value and the stator temperature of the motor to obtain the corrected stator temperature of the motor. When the corrected stator temperature of the motor is lower than the temperature warning upper limit, determine that the maximum torque of the motor is the peak torque of the motor. When the corrected stator temperature of the motor is higher than the failure temperature upper limit, determine that the maximum torque of the motor is zero. When the corrected stator temperature of the motor is lower than the failure temperature upper limit and higher than the temperature warning upper limit, determine that the maximum torque of the motor is a linear interpolation between the peak torque of the motor and zero. When the system demand torque is less than the maximum torque of the low-temperature motor, allocate the system demand torque to the low-temperature motor. When the system demand torque is greater than the sum of the maximum torque capabilities of the low-temperature motor and the high-temperature motor, control the low-temperature motor and the high-temperature motor to adopt the maximum torque capabilities. When the system demand torque is greater than the maximum torque capability of the low-temperature motor and less than the sum of the maximum torque capabilities of the low-temperature motor and the high-temperature motor, control the low-temperature motor to adopt the maximum torque capability, and control the high-temperature motor to supplement the difference between the system demand torque and the maximum torque capability.

2. The method according to claim 1, wherein The determining the thermal failure type of the motor of the electric drive system according to the ambient temperature and the stator temperature of the motor includes: When the stator temperature of the motor is higher than the failure temperature upper limit, or when the motor torque capability is lower than the product of the lower limit of the failure torque percentage and the maximum torque capability, determine that the motor of the electric drive system is the thermally failed motor. When the stator temperature of the motor is higher than the temperature warning upper limit, determine that the motor of the electric drive system is the thermally limited motor.

3. The method according to claim 1 or 2, characterized in that, Adjusting the operation mode of the powertrain of the electric drive system according to the motor thermal management state includes: When the motor thermal management state is a normal temperature state, keeping the operation mode of the powertrain of the electric drive system unchanged; When the motor thermal management state is a thermal protection state, adjusting the operation mode of the powertrain of the electric drive system to a dual-motor electric drive mode; When the motor thermal management state is a failure state, disabling the dual-motor electric drive mode; When the motor thermal management state is a semi-failure state, if the vehicle speed is lower than the lower limit of the parallel allowable vehicle speed, adjusting the operation mode of the powertrain of the electric drive system to the dual-motor electric drive mode; if the vehicle speed is higher than the lower limit of the parallel allowable vehicle speed, adjusting the operation mode of the powertrain of the electric drive system to the parallel mode.

4. A control device for an electric drive system, characterized in that, The electric drive system includes a low-temperature motor and a high-temperature motor; the electric drive system adopts a dual-motor electric drive mode; the device includes: An input module for obtaining the ambient temperature and the motor stator temperature; A thermal management module for determining the thermal failure type of the motor of the electric drive system according to the motor stator temperature, the thermal failure type including a thermally failed motor and a thermally limited motor; when all the motors of the electric drive system are the thermally failed motors, determining that the electric drive system is in a failure state; when one motor of the electric drive system is the thermally failed motor, determining that the electric drive system is in a semi-failure state; when all the motors of the electric drive system are not the thermally failed motors and at least one motor is a thermally limited motor, or, when the ambient temperature is higher than the ambient high-temperature upper limit and the transmission oil temperature exceeds the transmission high-temperature upper limit, determining that the electric drive system is in a thermal protection state; when the electric drive system is not in the failure state, the semi-failure state and the thermal protection state, determining that the electric drive system is in a normal temperature state; the failure state, the semi-failure state, the thermal protection state and the normal temperature state are all motor thermal management states; A powertrain coordination module for adjusting the operation mode of the powertrain of the electric drive system according to the motor thermal management state, the operation mode of the powertrain being used to represent the driving mode of the electric drive system; A torque distribution module, configured to determine a correction bias value according to the ambient temperature and the transmission oil temperature; calculate the sum of the correction bias value and the motor stator temperature to obtain a corrected motor stator temperature; determine the maximum motor torque as the motor peak torque when the corrected motor stator temperature is lower than the temperature warning upper limit; determine the maximum motor torque as zero when the corrected motor stator temperature is higher than the failure temperature upper limit; determine the maximum motor torque as a linear interpolation between the motor peak torque and zero when the corrected motor stator temperature is lower than the failure temperature upper limit and higher than the temperature warning upper limit; allocate the system demand torque to the low-temperature motor when the system demand torque is less than the maximum motor torque of the low-temperature motor; control the low-temperature motor and the high-temperature motor to adopt the maximum torque capacity when the system demand torque is greater than the sum of the maximum torque capacities of the low-temperature motor and the high-temperature motor; and control the low-temperature motor to adopt the maximum torque capacity and control the high-temperature motor to supplement the difference between the system demand torque and the maximum torque capacity when the system demand torque is greater than the maximum torque capacity of the low-temperature motor and less than the sum of the maximum torque capacities of the low-temperature motor and the high-temperature motor.

5. An electric vehicle, characterized in that, At least one program code is stored in the electric vehicle, and the program code is loaded and executed by a processor to implement the control method of the electric drive system according to any one of claims 1 to 3.

6. A computer program product comprising a computer program or instructions, characterized in that, When the computer program or instruction is executed by a processor, it implements the control method of the electric drive system according to any one of claims 1 to 3.

7. A computer-readable storage medium, characterized in that, At least one program code is stored in the computer-readable storage medium, and the program code is loaded and executed by a processor to implement the control method of the electric drive system according to any one of claims 1 to 3.

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