Torque control method and device for switching two-wheel drive into four-wheel drive

Abstract

The invention discloses a torque control method and device for switching two-wheel drive to four-wheel drive, and the method comprises the steps: obtaining the current output torque of a synchronous motor, the current output torque of an asynchronous motor and the opening degree of an accelerator in a torque coordination state; according to the accelerator opening degree, the current output torque of the asynchronous motor and the current output torque of the synchronous motor, the torque descending slope of the synchronous motor and the torque ascending slope of the asynchronous motor are determined; and according to the torque descending slope, the torque ascending slope, the current output torque of the asynchronous motor and the current output torque of the synchronous motor, a first request torque sent to the asynchronous motor and a second request torque sent to the synchronous motor are determined respectively so as to control the asynchronous motor and the synchronous motor to operate. Therefore, under the torque coordination state of switching the two-wheel drive to the four-wheel drive, the torque rising slope and the torque falling slope are controlled, so that the torque falling slope and the torque rising slope are kept consistent, and the running smoothness of the vehicle is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and in particular to a torque control method and device for switching from two-wheel drive to four-wheel drive. Background Art

[0002] Synchronous motors have high manufacturing costs but high operating efficiency, while asynchronous motors have low manufacturing costs but low operating efficiency. In order to achieve four-wheel drive configuration while taking into account manufacturing costs, electric vehicle manufacturers usually choose asynchronous motors in the front and synchronous motors in the rear when selecting motors, thereby reducing the manufacturing cost of the entire vehicle.

[0003] However, the asynchronous motor has low efficiency due to low speed and low torque, which will affect the driving range. In order to improve the driving range of electric vehicles with front asynchronous and rear synchronous motors, the economic mode is usually set to two-wheel drive by default, that is, the front motor is in the off-control mode (only the controller has 12V low-voltage power supply, no high-voltage power supply). Only in some working conditions, the two-wheel drive is switched to four-wheel drive.

[0004] When switching from two-wheel drive to four-wheel drive, the requested torque is transferred from the rear motor to the front motor. The control process is relatively complicated. The downward slope of the rear motor torque is large, while the upward slope of the front motor torque is small. As a result, the superposition of the requested torques of the front and rear motors will form a pit, causing the vehicle to stall. Summary of the invention

[0005] In view of the above problems, a torque control method and device for switching from two-wheel drive to four-wheel drive are proposed to solve the problem of vehicle jerking at the moment of switching from two-wheel drive to four-wheel drive.

[0006] According to a first aspect of the present invention, a torque control method for switching from two-wheel drive to four-wheel drive is provided, comprising:

[0007] In the torque coordination state, the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening are obtained;

[0008] Determining a torque decreasing slope of the synchronous motor and a torque increasing slope of the asynchronous motor respectively according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor;

[0009] Determine a first request torque sent to the asynchronous motor and a second request torque sent to the synchronous motor according to a torque decrease slope of the synchronous motor, a torque increase slope of the asynchronous motor, a current output torque of the asynchronous motor, and a current output torque of the synchronous motor;

[0010] The asynchronous motor and the synchronous motor are controlled to operate according to the first request torque and the second request torque.

[0011] Optionally, the step of determining the torque decreasing slope of the synchronous motor and the torque increasing slope of the asynchronous motor respectively according to the throttle opening, the current output torque of the asynchronous motor, and the current output torque of the synchronous motor comprises:

[0012] Determining a torque rising slope of the asynchronous motor according to the current output torque of the asynchronous motor and the throttle opening;

[0013] The torque reduction slope of the synchronous motor is determined according to the current output torque of the asynchronous motor.

[0014] Optionally, determining the torque rising slope of the asynchronous motor according to the current output torque of the asynchronous motor and the throttle opening includes:

[0015] According to the current output torque of the asynchronous motor and the throttle opening, the torque rising slope of the asynchronous motor is searched in a preset first relationship table and matched; the first relationship table includes a first calibrated torque and a throttle opening, and the first relationship table also includes a calibrated rising slope corresponding to the first calibrated torque and the throttle opening.

[0016] Optionally, determining the torque reduction slope of the synchronous motor according to the current output torque of the asynchronous motor includes:

[0017] According to the current output torque of the synchronous motor, the torque decrease slope of the synchronous motor is obtained by searching in a preset second relationship table; the second relationship table includes a second calibrated torque and a calibrated decrease slope corresponding to the second calibrated torque.

[0018] Optionally, in the torque coordination state, obtaining the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening includes:

[0019] If an activation command for switching from two-wheel drive to four-wheel drive is detected, the torque coordination state is entered, and the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening are obtained.

[0020] Optionally, before the activation instruction of switching from two-wheel drive to four-wheel drive is detected, the method further includes:

[0021] If the operating condition of the vehicle is the target condition, an activation instruction for switching the two-wheel drive to the four-wheel drive is generated; the target condition includes a synchronous motor failure condition, a rear wheel slip condition, an intelligent driving function activation condition, and a sudden acceleration condition.

[0022] Optionally, the method further includes:

[0023] Acquiring the actual operating torque of the asynchronous motor and the duration of the torque coordination state;

[0024] If the actual operating torque of the asynchronous motor is greater than the preset transfer torque, or the duration is greater than the preset transfer judgment time, the torque coordination state is exited.

[0025] According to a second aspect of the present invention, there is provided a torque control device for switching from two-wheel drive to four-wheel drive, comprising:

[0026] An acquisition module, used to acquire the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening in the torque coordination state;

[0027] A slope module, used to determine a torque decreasing slope of the synchronous motor and a torque increasing slope of the asynchronous motor according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor;

[0028] a torque module, configured to determine a first request torque sent to the asynchronous motor and a second request torque sent to the synchronous motor according to a torque decrease slope of the synchronous motor, a torque increase slope of the asynchronous motor, a current output torque of the asynchronous motor, and a current output torque of the synchronous motor;

[0029] An operation module is used to control the operation of the asynchronous motor and the synchronous motor respectively according to the first request torque and the second request torque.

[0030] According to a third aspect of the present invention, a controller is provided, the controller comprising: a memory, a processor and a computer program stored in the memory and executable on the processor, the processor executing the aforementioned torque control method for switching from two-wheel drive to four-wheel drive.

[0031] According to a fourth aspect of the present invention, a vehicle is provided, the vehicle comprising a vehicle body and a controller installed in the vehicle body, wherein the controller executes the aforementioned torque control method for switching from two-wheel drive to four-wheel drive.

[0032] The above one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0033] The embodiments of the present specification provide a torque control method and device for switching from two-wheel drive to four-wheel drive, which obtains the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening in a torque coordination state; determines the torque decrease slope of the synchronous motor and the torque increase slope of the asynchronous motor according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor; determines a first request torque sent to the asynchronous motor and a second request torque sent to the synchronous motor according to the torque decrease slope of the synchronous motor, the torque increase slope of the asynchronous motor, the current output torque of the asynchronous motor and the current output torque of the synchronous motor; and controls the operation of the asynchronous motor and the synchronous motor according to the first request torque and the second request torque. In this way, in the torque coordination state of switching from two-wheel drive to four-wheel drive, by controlling the torque rising slope of the asynchronous motor and the torque falling slope of the synchronous motor, the torque falling slope of the synchronous motor torque is kept consistent with the torque rising slope of the asynchronous motor, and then the first requested torque and the second requested torque are calculated to control the operation of the asynchronous motor and the synchronous motor, which can avoid the formation of a pit after the superposition of the requested torques of the synchronous motor and the asynchronous motor at the moment of switching from two-wheel drive to four-wheel drive, thereby ensuring the smoothness of vehicle operation.

[0034] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Also, throughout the accompanying drawings, the same reference figures are used to represent the same components. In the drawings:

[0036] Figure 1 A flow chart of a torque control method for switching from two-wheel drive to four-wheel drive in an embodiment of the present invention is shown.

[0037] Figure 2 A block diagram of a torque control device for switching from two-wheel drive to four-wheel drive in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0041] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] The embodiment of the present invention provides a torque control method for switching from two-wheel drive to four-wheel drive, combining Figure 1 As shown in the flowchart, the torque control method for switching from two-wheel drive to four-wheel drive includes steps 101 to 104:

[0043] Step 101: Under the torque coordination state, obtain the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening;

[0044] In this embodiment, the vehicle is a pure electric vehicle, and dual motors are provided on the vehicle. The dual motors include an asynchronous motor provided at a front end position and a synchronous motor provided at a rear end position.

[0045] Among them, the torque coordination state refers to a short period of time after the vehicle switches from two-wheel drive to four-wheel drive. The length of this period is determined by the transfer torque and the transfer judgment time. The transfer torque is affected by the model of the asynchronous motor, and the transfer torque can be determined by a calibration experiment of gear knocking. For example, if the transfer torque is 16Nm, when the actual operating torque of the asynchronous motor is less than or equal to 16Nm, the torque rise slope of the asynchronous motor needs to be limited and should not be too large (for example, greater than 100Nm), otherwise gear knocking is likely to occur.

[0046] Two-wheel drive means that the power is output by a synchronous motor, and four-wheel drive means that the power is output by both a synchronous motor and an asynchronous motor.

[0047] When switching from two-wheel drive to four-wheel drive, the vehicle controller will request the torque to be transferred from the synchronous motor (the rear motor of the vehicle) to the asynchronous motor (the front motor of the vehicle).

[0048] It is not difficult to understand that when the torque coordination state is just entered, that is, the moment when the two-wheel drive switches to four-wheel drive, the output torque of the asynchronous motor is 0, after which the output torque of the asynchronous motor will increase and the output torque of the synchronous motor will decrease.

[0049] It should be noted that when the asynchronous motor starts to output torque, due to gear meshing, the torque rising slope of the asynchronous motor is smaller than the torque falling slope of the synchronous motor in the initial short period of time, which is easy to cause setbacks and affect the smoothness of vehicle operation. Before the output torque of the asynchronous motor reaches the transfer torque, if the torque rising slope of the asynchronous motor is too large (for example, the torque rising slope is greater than 100Nm / s), the gear meshing is prone to knocking.

[0050] Based on the above situation, in the torque coordination state, this embodiment obtains the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening, and then processes them, so as to limit the slope of the torque decrease slope of the synchronous motor and the torque increase slope of the asynchronous motor.

[0051] In one embodiment, in the torque coordination state, obtaining the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening may include:

[0052] If an activation command for switching from two-wheel drive to four-wheel drive is detected, the torque coordination state is entered, and the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening are obtained.

[0053] In this embodiment, the vehicle controller of the vehicle will detect the operating conditions of the vehicle. In most operating conditions, the synchronous motor is used for power output. In some target conditions, the asynchronous motor and the synchronous motor are required to jointly output power, and at this time, it is necessary to switch the two-wheel drive to the four-wheel drive. The vehicle controller will generate an activation instruction for switching the two-wheel drive to the four-wheel drive. Among them, the target conditions may include synchronous motor failure conditions, rear wheel slip conditions, intelligent driving function activation conditions, and rapid acceleration conditions.

[0054] Among them, under the condition of synchronous motor failure, the power output of the synchronous motor is affected. In order to ensure the power of the vehicle, the two-wheel drive needs to be switched to four-wheel drive. Under the condition of rear wheel slippage, the asynchronous motor needs to output power to stabilize the vehicle. Under the condition of rapid acceleration, the power demand increases, and in order to meet the torque demand, the two-wheel drive needs to be switched to four-wheel drive.

[0055] After detecting the presence of an activation command, the vehicle enters the torque coordination state and collects the current output torque of the synchronous motor, the current output torque of the asynchronous motor, and the throttle opening. At the same time, the timing is started to calculate the duration of the torque coordination state.

[0056] The current output torque of the synchronous motor refers to the output torque of the synchronous motor at the current acquisition time. The current output torque of the asynchronous motor refers to the output torque of the asynchronous motor at the current acquisition time. The throttle opening corresponds to the depth of the driver's accelerator pedal. The deeper the driver presses the accelerator pedal, the greater the throttle opening. In this embodiment, the acquisition is performed once every cycle time. The cycle time can be 10ms, 12ms, etc., which is not limited in this embodiment.

[0057] Step 102: determining a torque decreasing slope of the synchronous motor and a torque increasing slope of the asynchronous motor respectively according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor;

[0058] In this embodiment, during the torque transfer process, the torque change of the synchronous motor is controlled by the torque drop slope. The torque change of the asynchronous motor is controlled by the torque rise slope. The slope control is divided into two stages, namely, in the torque coordination state, the torque rise slope of the asynchronous motor is limited to be not too large, and at the same time, the torque drop slope of the synchronous motor torque is kept consistent with the torque rise slope of the asynchronous motor. After the torque coordination state ends, the normal torque rise / fall slope is used to control the slope of the asynchronous motor and the synchronous motor.

[0059] In the torque coordination state, this embodiment determines the torque rising slope of the asynchronous motor according to the current output torque of the asynchronous motor and the throttle opening; and determines the torque falling slope of the synchronous motor according to the current output torque of the asynchronous motor.

[0060] Among them, the torque rising slope is positive, and the torque falling slope is negative. The torque rising slope refers to the rising rate of change of the output torque of the asynchronous motor. The larger the value of the torque rising slope, the faster the output torque of the asynchronous motor rises.

[0061] The torque drop slope refers to the rate of change of the torque drop of the synchronous motor. The larger the absolute value of the torque drop slope, the faster the output torque of the synchronous motor drops.

[0062] In one embodiment, when determining the torque rising slope, the following steps may be referred to:

[0063] According to the current output torque of the asynchronous motor and the throttle opening, the torque rising slope of the asynchronous motor is searched in a preset first relationship table and matched; the first relationship table includes a first calibrated torque and a throttle opening, and the first relationship table also includes a calibrated rising slope corresponding to the first calibrated torque and the throttle opening.

[0064] It should be noted that if it is the first collection moment in the torque coordination state, the current output torque of the asynchronous motor is 0. The vehicle controller will collect and obtain once every cycle time. If it is the nth collection moment in the torque coordination state, the current output torque of the asynchronous motor is not 0, where n is an integer greater than 1.

[0065] The first relationship table can be obtained according to the calibration experiment. The horizontal axis of the first relationship table is the first calibrated torque, which corresponds to the current output torque of the asynchronous motor at the current acquisition time. If the current acquisition time is not the first acquisition time, the current output torque of the asynchronous motor at the current acquisition time can also be understood as the first requested torque calculated at the previous acquisition time. The vertical axis of the first relationship table is the throttle opening. When the current output torque and throttle opening of the asynchronous motor are determined, the first relationship table is searched, the current output torque of the asynchronous motor is matched with the first calibrated torque, and the throttle opening is matched with the throttle opening in the table, so as to determine the calibrated rising slope, and then the calibrated rising slope is used as the torque rising slope.

[0066] In one embodiment, when determining the torque reduction slope, the following steps may be referred to:

[0067] According to the current output torque of the synchronous motor, the torque decrease slope of the synchronous motor is obtained by searching in a preset second relationship table; the second relationship table includes a second calibrated torque and a calibrated decrease slope corresponding to the second calibrated torque.

[0068] It should be noted that the second relationship table can be obtained according to the calibration experiment. The second calibration torque of the second relationship table corresponds to the current output torque of the synchronous motor at this acquisition time. If the current acquisition time is not the first acquisition time, the current output torque of the synchronous motor at this acquisition time can also be understood as the second request torque calculated at the previous acquisition time. When the current output torque of the synchronous motor is determined, the second relationship table is searched, and the current output torque of the synchronous motor is matched with the second calibration torque to determine the calibration descent slope, and then the calibration descent slope is used as the torque descent slope.

[0069] Step 103: determining a first request torque sent to the asynchronous motor and a second request torque sent to the synchronous motor according to a torque decrease slope of the synchronous motor, a torque increase slope of the asynchronous motor, a current output torque of the asynchronous motor, and a current output torque of the synchronous motor;

[0070] In this embodiment, in the torque coordination state, the absolute value of the torque rising slope is equal to the absolute value of the torque falling slope, so that before the output torque of the asynchronous motor is less than the preset transfer torque, the output torque of the asynchronous motor matches the output torque of the synchronous motor, and the reduced output torque of the synchronous motor is made as equal as possible to the increased output torque of the synchronous motor, so as to avoid setbacks and gear knocking, thereby ensuring smooth operation of the vehicle.

[0071] In the torque coordination state, the second requested torque is calculated according to the torque decreasing slope of the synchronous motor and the current output torque of the synchronous motor, and the first requested torque is calculated according to the torque increasing slope of the asynchronous motor and the current output torque of the asynchronous motor.

[0072] Step 104 : Controlling the asynchronous motor and the synchronous motor to operate respectively according to the first requested torque and the second requested torque.

[0073] In the torque coordination state, the second requested torque is calculated according to the torque decline slope of the synchronous motor and the current output torque of the synchronous motor, and sent to the synchronous motor control unit. The synchronous motor control unit controls the operation of the synchronous motor in the next cycle time according to the second requested torque. At the same time, the first requested torque is calculated according to the torque rise slope of the asynchronous motor and the current output torque of the asynchronous motor, and sent to the asynchronous motor control unit. The asynchronous motor control unit controls the operation of the asynchronous motor in the next cycle time according to the received first requested torque. The synchronous motor outputs power according to the second requested torque, and the asynchronous motor outputs power according to the first requested torque.

[0074] In addition, the actual operating torque of the asynchronous motor and the duration of the torque coordination state are obtained.

[0075] If the actual operating torque of the asynchronous motor is greater than the preset transfer torque, or the duration is greater than the preset transfer judgment time, the torque coordination state is exited. The transfer torque is mainly related to the asynchronous motor model. Different asynchronous motors may have different calibrated transfer torques. The transfer torque can be determined by a calibration experiment of gear knocking. For example, if the transfer torque is 16Nm, when the actual operating torque of the asynchronous motor is less than or equal to 16Nm, the torque rise slope of the asynchronous motor needs to be limited and should not be too large (for example, greater than 100Nm), otherwise gear knocking is likely to occur.

[0076] The actual operating torque of the asynchronous motor refers to the actual output torque measured after the asynchronous motor operates according to the first requested torque.

[0077] Among them, the actual operating torque of the asynchronous motor is greater than the preset transfer torque, which means that the torque of the asynchronous motor can be increased rapidly at this time and is no longer likely to cause gear knocking.

[0078] However, it should be noted that in certain working conditions, if the asynchronous motor is urgently needed for power output, it is not enough to simply consider whether it will cause gear knocking. For example, in the case of synchronous motor failure or rear wheel slip, safety considerations take precedence. Even if the actual operating torque of the asynchronous motor has not reached the transfer torque, as long as the duration is greater than the preset transfer judgment time, the torque coordination state needs to be exited.

[0079] After exiting the torque coordination state, the synchronous motor and the asynchronous motor are no longer subject to slope restrictions, and the slopes of the synchronous motor and the asynchronous motor can be controlled according to the normal descending slope and ascending slope. At this time, even if the torque ascending slope of the asynchronous motor is large, there is no need to worry about gear knocking.

[0080] For example:

[0081] The horizontal axis of Table 1 (first relationship table), i.e., the first calibration torque, is calibrated to [-100, -50, -20, -10, 0, 10, 16, 30, 100] in combination with the specific vehicle model and asynchronous motor model through calibration experiments, and the coordinates of the throttle opening on the vertical axis are calibrated to [0%, 20%, 40%, 60%, 80%] in combination with the specific vehicle model and asynchronous motor model. Table 2 (second relationship table) is calibrated in combination with the specific vehicle model and motor model, as shown in Table 2 below.

[0082] At 60% throttle opening, at the moment of activation command of switching from two-wheel drive to four-wheel drive, t=0, the current output torque of the asynchronous motor starts from 0, and then gradually increases to the motor distributed torque of 16Nm (the motor distributed torque is determined by the current vehicle speed and throttle opening). The current output torque of the synchronous motor starts to drop from 300Nm to 284Nm.

[0083] In the torque coordination state, according to the current output torque and throttle opening of the asynchronous motor, the torque rising slope is matched in Table 1 (the torque rising slope is 100Nm / s obtained by interpolation table lookup), and after the torque rising slope is controlled, the first request torque of the asynchronous motor is calculated and output to the asynchronous motor control unit through the bus for controlling the operation of the asynchronous motor. At the same time, the current output torque of the synchronous motor is matched in Table 2 to obtain the torque falling slope (the torque falling slope is -100Nm / s obtained by interpolation table lookup). After the torque falling slope is controlled, the second request torque of the synchronous motor is calculated and output to the synchronous motor control unit through the bus for controlling the operation of the synchronous motor.

[0084] When the actual operating torque of the asynchronous motor is greater than the preset transfer torque of 16Nm, or the duration of the torque coordination state exceeds the transfer judgment time of 0.16s, the torque coordination state is exited, that is, the torque transfer slope control is exited. After that, the slope change of the asynchronous motor torque is normally controlled by Table 1 and Table 3. The slope change of the synchronous motor torque is normally controlled by Table 4 and Table 5. Thus, the new first request torque of the asynchronous motor and the new second request torque of the synchronous motor are obtained, and output to the asynchronous motor and the synchronous motor for execution through the bus.

[0085]

[0086] Table 1 - First relationship table

[0087] The second calibration torque -300 -100 -30 0 10 16 180 300 500 Slope -750 -500 -300 -100 -100 -250 -500 -900 -1200

[0088] Table 2 - Second relationship table

[0089] Rated torque -300 -100 -30 -10 10 30 180 300 500 Slope -750 -500 -300 -100 -100 -250 -500 -900 -1200

[0090] Table 3-Normal torque drop rate of asynchronous motor

[0091]

[0092] Table 4-Normal rising slope of synchronous motor torque

[0093] Rated torque -300 -100 -30 0 10 16 180 300 500 Slope -750 -500 -300 -100 -100 -250 -500 -900 -1200

[0094] Table 5-Normal decrease slope of synchronous motor torque

[0095] In summary, the embodiment of the present specification provides a torque control method for switching from two-wheel drive to four-wheel drive, which obtains the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening in the torque coordination state; determines the torque decrease slope of the synchronous motor and the torque increase slope of the asynchronous motor according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor; determines the first request torque sent to the asynchronous motor and the second request torque sent to the synchronous motor according to the torque decrease slope of the synchronous motor, the torque increase slope of the asynchronous motor, the current output torque of the asynchronous motor and the current output torque of the synchronous motor; and controls the operation of the asynchronous motor and the synchronous motor according to the first request torque and the second request torque. In this way, in the torque coordination state of switching from two-wheel drive to four-wheel drive, by controlling the torque rising slope of the asynchronous motor and the torque falling slope of the synchronous motor, the torque falling slope of the synchronous motor torque is kept consistent with the torque rising slope of the asynchronous motor, and then the first requested torque and the second requested torque are calculated to control the operation of the asynchronous motor and the synchronous motor, which can avoid the formation of pits after the superposition of the requested torques of the synchronous motor and the asynchronous motor at the moment of switching from two-wheel drive to four-wheel drive, and avoid gear knocking, thereby ensuring the smoothness of vehicle operation.

[0096] Based on the same inventive concept, Figure 2 As shown, an embodiment of the present invention further provides a torque control device for switching from two-wheel drive to four-wheel drive, comprising:

[0097] An acquisition module, used to acquire the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening in the torque coordination state;

[0098] A slope module, used to determine a torque decreasing slope of the synchronous motor and a torque increasing slope of the asynchronous motor according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor;

[0099] a torque module, configured to determine a first request torque sent to the asynchronous motor and a second request torque sent to the synchronous motor according to a torque decrease slope of the synchronous motor, a torque increase slope of the asynchronous motor, a current output torque of the asynchronous motor, and a current output torque of the synchronous motor;

[0100] An operation module is used to control the operation of the asynchronous motor and the synchronous motor respectively according to the first request torque and the second request torque.

[0101] Optionally, the slope module is also used to:

[0102] Determining a torque rising slope of the asynchronous motor according to the current output torque of the asynchronous motor and the throttle opening;

[0103] The torque reduction slope of the synchronous motor is determined according to the current output torque of the asynchronous motor.

[0104] Optionally, the slope module is also used to:

[0105] According to the current output torque of the asynchronous motor and the throttle opening, the torque rising slope of the asynchronous motor is searched in a preset first relationship table and matched; the first relationship table includes a first calibrated torque and a throttle opening, and the first relationship table also includes a calibrated rising slope corresponding to the first calibrated torque and the throttle opening.

[0106] Optionally, the slope module is also used to:

[0107] According to the current output torque of the synchronous motor, the torque decrease slope of the synchronous motor is obtained by searching in a preset second relationship table; the second relationship table includes a second calibrated torque and a calibrated decrease slope corresponding to the second calibrated torque.

[0108] Optionally, the acquisition module is also used to:

[0109] If an activation command for switching from two-wheel drive to four-wheel drive is detected, the torque coordination state is entered, and the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening are obtained.

[0110] Optionally, the acquisition module is also used to:

[0111] If the operating condition of the vehicle is the target condition, an activation instruction for switching the two-wheel drive to the four-wheel drive is generated; the target condition includes a synchronous motor failure condition, a rear wheel slip condition, an intelligent driving function activation condition, and a sudden acceleration condition.

[0112] Optionally, the runtime module is also used to:

[0113] Acquiring the actual operating torque of the asynchronous motor and the duration of the torque coordination state;

[0114] If the actual operating torque of the asynchronous motor is greater than the preset transfer torque, or the duration is greater than the preset transfer judgment time, the torque coordination state is exited.

[0115] In summary, the embodiment of the present specification provides a torque control device for switching from two-wheel drive to four-wheel drive, which obtains the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening in the torque coordination state; determines the torque decrease slope of the synchronous motor and the torque increase slope of the asynchronous motor according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor; determines the first requested torque sent to the asynchronous motor and the second requested torque sent to the synchronous motor according to the torque decrease slope of the synchronous motor, the torque increase slope of the asynchronous motor, the current output torque of the asynchronous motor and the current output torque of the synchronous motor; and controls the operation of the asynchronous motor and the synchronous motor according to the first requested torque and the second requested torque. In this way, in the torque coordination state of switching from two-wheel drive to four-wheel drive, by controlling the torque rising slope of the asynchronous motor and the torque falling slope of the synchronous motor, the torque falling slope of the synchronous motor torque is kept consistent with the torque rising slope of the asynchronous motor, and then the first requested torque and the second requested torque are calculated to control the operation of the asynchronous motor and the synchronous motor, which can avoid the formation of a pit after the superposition of the requested torques of the synchronous motor and the asynchronous motor at the moment of switching from two-wheel drive to four-wheel drive, thereby ensuring the smoothness of vehicle operation.

[0116] Technicians in the relevant field can clearly understand that for the convenience and simplicity of description, the specific working process of the torque control device for switching from two-wheel drive to four-wheel drive described above can refer to the corresponding process in the aforementioned method, and will not be elaborated here.

[0117] Based on the same inventive concept, an embodiment of the present invention also provides a controller, which includes a torque control device for switching from two-wheel drive to four-wheel drive, a memory, a processor and a communication unit. The memory stores machine-readable instructions executable by the processor. When the controller is running, the processor and the memory communicate through a bus, the processor executes the machine-readable instructions, and executes the torque control method for switching from two-wheel drive to four-wheel drive.

[0118] The memory, processor and communication unit components are electrically connected to each other directly or indirectly to achieve signal transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses or signal lines. The torque control device for switching from two-wheel drive to four-wheel drive includes at least one software function module that can be stored in the memory in the form of software or firmware. The processor is used to execute the executable module stored in the memory (for example, the software function module or computer program included in the torque control device for switching from two-wheel drive to four-wheel drive).

[0119] Among them, the memory can be, but is not limited to, random access memory (Random Access Memory, RAM), read only memory (Read Only Memory, ROM), programmable read-only memory (Programmable Read-Only Memory, PROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, EPROM), electrically erasable read-only memory (Electric Erasable Programmable Read-Only Memory, EEPROM), etc.

[0120] In some embodiments, the processor is used to perform one or more functions described in this embodiment. In some embodiments, the processor may include one or more processing cores (eg, a single-core processor (S) or a multi-core processor (S)).

[0121] In this embodiment, the memory is used to store the program, and the processor is used to execute the program after receiving the execution instruction. The process definition method disclosed in any implementation of this embodiment can be applied to the processor, or implemented by the processor.

[0122] The communication unit is used to establish a communication connection between the controller and other devices through the network, and to send and receive data through the network.

[0123] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the controller described above can refer to the corresponding process in the aforementioned method, and will not be elaborated here.

[0124] Based on the same inventive concept, an embodiment of the present invention further provides a vehicle, including a vehicle body and a controller installed in the vehicle body, the vehicle is a pure electric vehicle, and a synchronous motor and an asynchronous motor are installed in the vehicle. The controller is used to implement the above-mentioned torque control method for switching from two-wheel drive to four-wheel drive.

[0125] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the controller of the vehicle described above can refer to the corresponding process in the aforementioned method, and will not be elaborated here.

[0126] The above are only various embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A torque control method for switching from two-wheel drive to four-wheel drive, characterized in that: include: In the torque coordination state, the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening are obtained; Determining a torque decreasing slope of the synchronous motor and a torque increasing slope of the asynchronous motor respectively according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor; Determine a first request torque sent to the asynchronous motor and a second request torque sent to the synchronous motor according to a torque decrease slope of the synchronous motor, a torque increase slope of the asynchronous motor, a current output torque of the asynchronous motor, and a current output torque of the synchronous motor; The asynchronous motor and the synchronous motor are controlled to operate according to the first request torque and the second request torque.

2. The method according to claim 1, characterized in that The step of determining the torque decreasing slope of the synchronous motor and the torque increasing slope of the asynchronous motor respectively according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor comprises: Determining a torque rising slope of the asynchronous motor according to the current output torque of the asynchronous motor and the throttle opening; The torque reduction slope of the synchronous motor is determined according to the current output torque of the asynchronous motor.

3. The method according to claim 2, characterized in that Determining the torque rising slope of the asynchronous motor according to the current output torque of the asynchronous motor and the throttle opening includes: According to the current output torque of the asynchronous motor and the throttle opening, the torque rising slope of the asynchronous motor is searched in a preset first relationship table and matched; the first relationship table includes a first calibrated torque and a throttle opening, and the first relationship table also includes a calibrated rising slope corresponding to the first calibrated torque and the throttle opening.

4. The method according to claim 2, characterized in that: The step of determining the torque reduction slope of the synchronous motor according to the current output torque of the asynchronous motor comprises: According to the current output torque of the synchronous motor, the torque decrease slope of the synchronous motor is obtained by searching in a preset second relationship table; the second relationship table includes a second calibrated torque and a calibrated decrease slope corresponding to the second calibrated torque.

5. The method according to claim 1, characterized in that: The step of obtaining the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening in the torque coordination state includes: If an activation command for switching from two-wheel drive to four-wheel drive is detected, the torque coordination state is entered, and the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening are obtained.

6. The method according to claim 5, characterized in that Before the activation instruction of switching from two-wheel drive to four-wheel drive is detected, the method further includes: If the operating condition of the vehicle is the target condition, an activation instruction for switching the two-wheel drive to the four-wheel drive is generated; the target condition includes a synchronous motor failure condition, a rear wheel slip condition, an intelligent driving function activation condition, and a sudden acceleration condition.

7. The method according to claim 1, characterized in that The method further comprises: Acquiring the actual operating torque of the asynchronous motor and the duration of the torque coordination state; If the actual operating torque of the asynchronous motor is greater than the preset transfer torque, or the duration is greater than the preset transfer judgment time, the torque coordination state is exited.

8. A torque control device for switching from two-wheel drive to four-wheel drive, characterized in that: include: An acquisition module, used to acquire the current output torque of the synchronous motor, the current output torque of the asynchronous motor and the throttle opening in the torque coordination state; A slope module, used to determine a torque decreasing slope of the synchronous motor and a torque increasing slope of the asynchronous motor according to the throttle opening, the current output torque of the asynchronous motor and the current output torque of the synchronous motor; a torque module, configured to determine a first request torque sent to the asynchronous motor and a second request torque sent to the synchronous motor according to a torque decrease slope of the synchronous motor, a torque increase slope of the asynchronous motor, a current output torque of the asynchronous motor, and a current output torque of the synchronous motor; An operation module is used to control the operation of the asynchronous motor and the synchronous motor respectively according to the first request torque and the second request torque.

9. A controller, characterized in that: The controller includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the torque control method for switching from two-wheel drive to four-wheel drive described in any one of claims 1-7 is implemented.

10. A vehicle, characterized in that: The vehicle includes a vehicle body and a controller installed in the vehicle body, wherein the controller executes the torque control method for switching from two-wheel drive to four-wheel drive as described in any one of claims 1-7.

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