Torque control system of electric vehicle

Abstract

The utility model discloses a torque control system of an electric vehicle. The torque control system comprises an accelerator pedal, a brake pedal, a motor assembly and a control module. The motor assembly is electrically connected with the accelerator pedal and the brake pedal and is used for outputting forward torque. The control module is electrically connected with the motor assembly, the accelerator pedal and the brake pedal. The control module is configured to obtain the vehicle speed of the electric vehicle and the pedal opening degree of an accelerator pedal and determine the target acceleration of the electric vehicle according to the vehicle speed and the pedal opening degree; calculating the target acceleration and the longitudinal acceleration of the electric vehicle to obtain an acceleration difference value; determining the torque variation according to the acceleration difference and the actual vehicle speed; and performing torque superposition calculation on the forward torque according to the torque variation, and controlling the motor assembly to correct the forward torque according to a calculation result. Therefore, according to the torque control system of the electric vehicle, calibration meters stored in the system can be reduced, and the calibration time is shortened.

Description

Technical Field

[0001] This utility model relates to a torque control system, and more particularly to a torque control system for an electric vehicle. Background Technology

[0002] Electric vehicles (EVs) or hybrid vehicles propel themselves by outputting torque through their internal drive system. Generally, EVs control torque output by incorporating driving modes and energy recovery levels, and then using different combinations of these settings and calibration tables to determine the final torque output. Because different driving modes and energy recovery levels require different calibration tables, the sheer number of calibration tables increases the memory requirements of the EV's internal controller and also prolongs calibration time.

[0003] Furthermore, existing electric vehicles control the motor to output corresponding torque based on the torque control commands given by the driver, thereby adjusting the vehicle's acceleration. In other words, when an electric vehicle is traveling on roads with varying gradients, the driver needs to frequently press the accelerator pedal to adjust the output torque and control the speed, increasing the complexity of vehicle control for the driver.

[0004] Therefore, how to improve the control architecture design of electric vehicles to overcome the above-mentioned defects has become one of the important issues to be addressed in this field. Utility Model Content

[0005] This utility model mainly provides a torque control system for electric vehicles to solve the technical problems of excessive workload for torque calibration in the existing control system of electric vehicles, and the need for drivers to frequently change the throttle opening.

[0006] To address the aforementioned technical problems, one technical solution adopted by this utility model is to provide a torque control system for an electric vehicle, comprising an accelerator pedal, a brake pedal, a motor assembly, and a control module. The motor assembly is electrically connected to the accelerator pedal and the brake pedal, and is used to output positive torque. The control module is electrically connected to the motor assembly, the accelerator pedal, and the brake pedal. The control module is configured to: acquire the vehicle speed and the accelerator pedal opening of the electric vehicle, and determine the target acceleration of the electric vehicle accordingly; calculate the acceleration difference between the target acceleration and the longitudinal acceleration of the electric vehicle; determine the torque change based on the acceleration difference and the actual vehicle speed; and perform torque superposition calculation on the positive torque based on the torque change, and control the motor assembly to correct the positive torque based on the calculation result.

[0007] Preferably, in the step of acquiring the vehicle speed and accelerator pedal opening of the electric vehicle and determining the target acceleration of the electric vehicle, the control module is further configured to: select an acceleration correspondence table corresponding to the current driving mode, wherein the acceleration correspondence table contains the correspondence between the vehicle speed, accelerator pedal opening and target acceleration; and determine the target acceleration corresponding to the current vehicle speed and current pedal opening from the acceleration correspondence table.

[0008] Preferably, in the step of determining the amount of torque change based on the acceleration difference and vehicle speed, the control module is further configured to: select a torque change correspondence table corresponding to the current driving mode, wherein the torque change correspondence table contains the correspondence between the vehicle speed, acceleration difference and torque change of the electric vehicle; and determine the amount of torque change corresponding to the current vehicle speed and acceleration difference from the torque change correspondence table.

[0009] Preferably, in the step of performing torque superposition calculation on the positive torque based on the torque change to control the motor assembly to correct the positive torque, the control module is further configured to: output a predetermined positive torque through torque superposition calculation; and determine that the predetermined positive torque is within the torque limit range.

[0010] Preferably, the predetermined positive torque being within the torque limiting range means that the predetermined positive torque is greater than the lower limit and less than the upper limit; wherein, the upper limit is equal to the maximum positive torque that the motor assembly can output, and the lower limit is equal to the absolute value of the preset braking torque output by the motor assembly.

[0011] Preferably, when the driver releases the accelerator pedal and does not press the brake pedal, the preset braking torque is obtained by multiplying the maximum braking torque that the electric motor assembly can output by a braking torque setting percentage.

[0012] Preferably, the braking torque setting percentage is any value between 0 and 100%.

[0013] Preferably, the braking torque setting percentage is set by the driver using the electric vehicle's onboard information system.

[0014] Preferably, when the driver releases the accelerator pedal and immediately depresses the brake pedal, the preset braking torque is obtained by the control module through superposition calculation of braking torque based on the braking torque correspondence table.

[0015] Preferably, when the driver releases the accelerator pedal and then depresses the brake pedal after a period of time, the electric motor assembly outputs the current braking torque. If the current braking torque is greater than or equal to the target braking torque obtained by the control module according to the braking torque correspondence table, then the current braking torque is the preset braking torque. If the current braking torque is less than the target braking torque obtained by the control module according to the braking torque correspondence table, then the control module performs braking torque superposition calculation according to the braking torque setting percentage and braking torque correspondence table to control the electric motor assembly to correct the current braking torque so that it is equal to the target braking torque, and then the target braking torque is the preset braking torque.

[0016] The torque control system for electric vehicles provided by this invention controls the output torque of the electric vehicle by issuing acceleration control commands. The driver only needs to determine different target accelerations to calculate the most appropriate torque command value required by the vehicle at that moment. Therefore, it can significantly reduce the number of calibration tables stored in the system and reduce calibration time. Furthermore, since the output torque of the electric vehicle is adjusted and calculated according to the overall vehicle acceleration, it can reduce the impact of road surface changes, slopes, and vehicle load during vehicle operation. The driver no longer needs to frequently press the accelerator pedal according to road conditions, which helps to reduce the complexity of vehicle operation. Attached Figure Description

[0017] Figure 1 This is a functional block diagram of the electric vehicle torque control system of this utility model.

[0018] Figure 2 This is a functional block diagram of the control module of the electric vehicle torque control system of this utility model.

[0019] Figure 3 This is a diagram illustrating a driver operating an electric vehicle.

[0020] Figure 4 This is a schematic diagram of steps S1 to S4 of the torque control system of the electric vehicle of this utility model.

[0021] Figure 5 This is a schematic diagram of steps S11 to S12 of the torque control system for an electric vehicle according to this utility model.

[0022] Figure 6 This is a schematic diagram of the acceleration correspondence table of the torque control system of the electric vehicle of this utility model.

[0023] Figure 7 This is a schematic diagram of steps S31 to S32 of the torque control system of the electric vehicle of this utility model.

[0024] Figure 8 This is a schematic diagram of steps S41 to S42 of the torque control system of the electric vehicle of this utility model.

[0025] Figure 9 This is a schematic diagram of steps S101 to S109 of the torque control system for the electric vehicle of this utility model. Detailed Implementation

[0026] This document may use terms such as “first,” “second,” and “third” to describe various components, but these terms should not limit the scope of the components. These terms are primarily used to distinguish one component from another. Additionally, the term “or” as used herein may, depending on the context, include any combination of one or more related items listed.

[0027] Example

[0028] See Figure 1 As shown, this utility model provides a torque control system suitable for a mobile vehicle D. In a preferred embodiment of this utility model, the mobile vehicle D is illustrated as an electric vehicle. However, this utility model is not limited thereto; for example, the mobile vehicle D may also be a hybrid electric vehicle.

[0029] Mainly, the torque control system of the electric vehicle of this utility model includes: a control module 1, a motor assembly 2, an accelerator pedal 3, and a brake pedal 4. The control module 1 is electrically connected to the motor assembly 2, the accelerator pedal 3, and the brake pedal 4, and the motor assembly 2 is electrically connected to the accelerator pedal 3 and the brake pedal 4. For example, the motor assembly 2 can be an electric motor. When the driver presses the accelerator pedal 3, the motor assembly 2 outputs positive torque to drive the electric vehicle to accelerate. For example, the accelerator pedal 3 can be an accelerator pedal or a combination of accelerator and accelerator pedal. Specifically, if the vehicle D is an electric vehicle, the accelerator pedal 3 can be an accelerator pedal; if the vehicle D is a hybrid vehicle, the accelerator pedal 3 can be a combination of accelerator and accelerator pedal. The electric vehicle torque control system further includes a vehicle speed sensor 5, an acceleration sensor 6, and a torque sensor 7. The vehicle speed sensor 5 is used to detect the vehicle speed, and the acceleration sensor 6 is used to detect the longitudinal acceleration of the electric vehicle.

[0030] See Figure 2As shown, the control module 1 may include a microcontroller 11 and a vehicle control unit (VCU) 12, but this invention is not limited thereto. For example, the control module 1 may further include an electronic control unit (ESC) controller 13, a motor control unit (MCU) 14, and a storage unit 15, etc. The storage unit 15 may include, but is not limited to, random access memory (RAM), flash memory, and solid-state drive (SSD), etc. In this invention, the control module 1 can be regarded as an assembly of all control components, signal processing components, and storage components in the vehicle. The control module 1 can be used for vehicle control and for calculating, processing, and storing vehicle operating data or parameters. For example, the control module 1 can receive various sensing signals output by various sensing components in the vehicle to obtain vehicle information, and further read and analyze them to output corresponding control signals to relevant components to command them to perform corresponding actions.

[0031] Continue reading Figure 1 To further understand the torque control system of the electric vehicle of this utility model, the process steps S1 to S4 of the torque control system of this utility model will be further described below, which can be referred to in conjunction with the following text. Figure 4 As shown:

[0032] Step S1: Obtain the vehicle speed and accelerator pedal opening of the electric vehicle, and determine the target acceleration of the electric vehicle accordingly.

[0033] Step S2: Calculate the target acceleration and the longitudinal acceleration of the electric vehicle to obtain the acceleration difference.

[0034] Step S3: Determine the torque change based on the acceleration difference and the actual vehicle speed.

[0035] Step S4: Calculate the positive torque by superimposing the torque based on the torque change, and control the motor assembly to correct the positive torque based on the calculation results.

[0036] See Figure 4 and Figure 5 And refer to Figure 1 As shown. In step S1, when the driver presses the accelerator pedal 3 to accelerate the electric vehicle, the control module 1 detects and obtains the pedal opening of the accelerator pedal 3 through the accelerator pedal position sensor 31, and detects and obtains the vehicle speed through the vehicle speed sensor 5. Next, the control module 1 selects the acceleration correspondence table corresponding to the current driving mode (step S11), and then determines the target acceleration corresponding to the current vehicle speed and the current accelerator pedal opening from the acceleration correspondence table (step S12).

[0037] See Figure 6 As shown, the acceleration correspondence table contains the correspondence between the electric vehicle's speed, the accelerator pedal opening, and the target acceleration. The electric vehicle of this invention can have multiple driving modes, such as ECO mode, normal mode, and sport mode. Specifically, different driving modes have different acceleration correspondence tables. Multiple acceleration correspondence tables, as well as the torque change correspondence table and braking torque correspondence table mentioned below, can all be stored in the storage unit 15 of the control module 1 (see...). Figure 2 ).

[0038] For example, when the driver is driving the electric vehicle in normal mode, control module 1 selects the acceleration correspondence table corresponding to normal mode. The vertical axis number of the acceleration correspondence table represents the pedal opening T of the accelerator pedal 3 (see reference). Figure 3 The horizontal axis of the acceleration correspondence table represents the vehicle speed of the electric vehicle, in kph (kilometers per hour). See also... Figure 3 As shown, the range of pedal opening T can be between 0% and 100%. 0% indicates that the accelerator pedal 3 is completely released and not pressed, while 100% indicates that the accelerator pedal 3 is pressed to the bottom, that is, fully pressed.

[0039] It should be noted that, Figure 6 The acceleration correspondence table shown does not display all acceleration values ​​(unit: km / h²), but only provides a portion of the figures for illustrative purposes. It should also be noted that... Figure 6 The acceleration values ​​in the acceleration correspondence table shown are for reference only, and this utility model does not impose any limitations on them.

[0040] For example, if the driver depresses the accelerator pedal 3 to a pedal opening T of 20%, the electric vehicle accelerates from a standstill (0 kph) to 40 kph. At this point, the electric vehicle has a positive target acceleration. During acceleration, the value of the target acceleration can be determined by the control module 1 based on an acceleration correspondence table. By looking up the table, the control module 1 selects the target acceleration corresponding to the current vehicle speed and the current pedal opening. With the pedal opening T maintained at 20%, as the vehicle speed gradually increases from 0 kph to the predetermined target speed (40 kph), the target acceleration will gradually decrease. Figure 6 As shown, the target acceleration decreased from 1.5 km / h², 1.2 km / h², 1 km / h²... to 0.

[0041] Continue reading Figure 6If the driver further increases the vehicle speed to 60 kph, they can depress the accelerator pedal 3, increasing the pedal opening T to 30%. At this point, the target acceleration increases from 0 km / h² to 0.7 km / h². Then, while maintaining the pedal opening T at 30%, as the vehicle speed is gradually increased from 40 kph to another predetermined target speed (60 kph), the target acceleration decreases from 0.7 km / h², 0.5 km / h², and so on, until it reaches 0.

[0042] On the other hand, if the driver wants to reduce the vehicle speed, for example from 40 kph to 0 kph, they can fully release the accelerator pedal 3, causing the pedal opening T to immediately decrease from 20% to 0. At this time, the electric vehicle has a reverse target acceleration (i.e., Figure 6 The negative acceleration values ​​in the data are as follows: the target acceleration increases from 0, -0.1 km / h², -0.2 km / h², ... to -0.9 km / h². Then, with the pedal opening T maintained at 0, as the vehicle speed gradually decreases from 40 kph to the predetermined target speed (0 kph, i.e., a complete stop), the target acceleration decreases from -0.9 km / h², -0.8 km / h², -0.7 km / h², ... to 0.

[0043] See Figure 4 and Figure 7 And refer to Figure 1 After selecting the corresponding target acceleration from the acceleration correspondence table, control module 1 subtracts the target acceleration from the longitudinal acceleration obtained by acceleration sensor 6 to calculate the acceleration difference (step S2). Based on the acceleration difference and the actual speed of the electric vehicle, it determines the torque change (step S3). In step S3, control module 1 selects the torque change correspondence table corresponding to the current driving mode (step S31), and then determines the torque change corresponding to the current speed and acceleration difference from the torque change correspondence table (step S32).

[0044] The torque change correspondence table contains the relationship between the electric vehicle's speed, acceleration difference, and torque change. Different electric vehicles have different torque change correspondence tables for different driving modes. When the driver is driving the electric vehicle in normal mode, control module 1 selects the torque change correspondence table corresponding to normal mode. By looking up the table, control module 1 can select the torque change corresponding to the acceleration difference and the current vehicle speed (for ease of explanation, this is referred to as the first torque change).

[0045] See Figure 8As shown, the control module 1 performs torque superposition calculation on the positive torque based on the torque change, and controls the motor assembly 2 to correct the positive torque based on the calculation result (step S4). In step S4, the control module 1 outputs a predetermined positive torque through torque superposition calculation (step S41), and determines that the predetermined positive torque is within the torque limit range (step S42).

[0046] In detail, the control module 1 controls the motor assembly 2 to adjust the output positive torque based on the selected first torque change amount. That is, the current output positive torque is added to the first torque change amount to obtain the corrected predetermined positive torque (for ease of explanation, it is called the first predetermined positive torque).

[0047] The electric vehicle increases its speed by outputting a first predetermined positive torque through the motor assembly 2. Then, the control module 1 obtains the increased speed and uses a lookup table (acceleration correspondence table) to obtain another target acceleration, and calculates another acceleration difference accordingly. Next, it obtains another torque change (called the second torque change) by looking up a table (torque change correspondence table). Based on the second torque change, the control module 1 controls the motor assembly 2 to adjust the previously output first predetermined positive torque, adding the second torque change to the first predetermined positive torque to obtain a revised positive torque. In this way, the control module 1 can repeatedly perform torque superposition calculations on the positive torque output by the motor assembly 2, continuously correcting the desired positive torque output by the motor assembly 2.

[0048] Therefore, the electric vehicle torque control system of this utility model utilizes a torque superposition calculation method. When the driver presses the accelerator pedal 3, the system determines the required acceleration of the entire vehicle based on the pedal opening T and calculates the output torque. If the driver uses a fixed pedal opening T to drive the electric vehicle, it will maintain a constant speed when the vehicle accelerates to the set target speed, eliminating the need to control the accelerator pedal to maintain a constant speed, unlike existing cars (whether gasoline or electric). Furthermore, because the torque control system adjusts the output torque according to the actual vehicle condition, the driver's driving comfort will not differ significantly when the vehicle load changes or when encountering changes in road slope. The driver's perception of the vehicle's driving state, such as the acceleration felt when pressing the accelerator pedal, will not differ noticeably, making the vehicle easier to control.

[0049] It should be noted that before the motor assembly 2 outputs the predetermined positive torque, the control module 1 first determines that the predetermined positive torque is within the torque limit range. (See also...) Figure 9As shown, the torque limiting range refers to the predetermined positive torque being greater than the lower limit and less than the upper limit. The upper limit is the maximum positive torque that the motor assembly 2 can output, and the lower limit is the absolute value of the preset braking torque output by the motor assembly 2.

[0050] The lower limit of the positive torque is calculated by the integrated system of the vehicle controller 12, motor controller 14, and battery management system (BMS) (not shown) in the electric vehicle's control module 1. Generally, the lower limit of the positive torque output by the electric vehicle must be greater than or at least equal to the preset braking torque output by the electric vehicle. See also... Figure 9 As shown, the preset braking torque is mainly generated when the electric vehicle decelerates. When the driver releases the accelerator pedal 3, or even further depresses the brake pedal 4 to decelerate the electric vehicle (the control module 1 can detect the pedal opening of the brake pedal 4 through the brake pedal position sensor 41), the control module 1 activates the regenerative braking function. At this time, the motor assembly 2 reverses its running direction and outputs the preset braking torque to drive the electric vehicle to decelerate. During the deceleration process, the motor assembly 2 acts as a generator, converting the energy of the electric vehicle into electrical energy and storing it in the electric vehicle's battery (not shown in the figure), which is the so-called energy recovery.

[0051] The deceleration scenarios for electric vehicles can be mainly divided into those with the brake pedal pressed and those without. These will be explained in detail below.

[0052] See Figure 1 and Figure 2 As shown, for example, when the driver releases the accelerator pedal 3 but does not press the brake pedal 4, the preset braking torque is obtained by multiplying the maximum braking torque that the electric motor assembly 2 can output by a braking torque setting percentage. The braking torque setting percentage can be set by the driver through the electric vehicle's in-vehicle information system (IVI), and the braking torque setting percentage can be any value from 0 to 100%. The in-vehicle information system is mainly integrated into the vehicle's display (not shown), which provides the driver with multimedia, navigation, music, and communication functions, as well as allows the driver to adjust the aforementioned braking torque setting percentage.

[0053] Existing electric vehicles also provide drivers with a calibrated braking torque output from the electric motor. Electric vehicles offer several regenerative braking calibration levels (e.g., 20%, 50%, 70%, etc.) in their onboard information systems, allowing drivers to adjust the braking torque value by selecting different calibration levels. However, since the braking torque corresponding to these calibration levels is a fixed value preset by the manufacturer, drivers can only select, not freely adjust, to their desired braking torque value. In other words, drivers can only select one level to adjust the braking torque to a fixed ratio, while other ratio ranges not provided in the onboard information system are unavailable. In contrast, the electric vehicle torque control system of this invention provides stepless braking torque setting, allowing drivers to adjust the desired braking torque value according to their personal preferences, improving ride comfort during deceleration.

[0054] Regarding situations where the driver presses the brake pedal when an electric vehicle decelerates, this can be further divided into the following two situations, which can be referred to... Figure 9 As shown: the driver releases the accelerator pedal 3 and immediately presses the brake pedal 4; and the driver releases the accelerator pedal 3 and then presses the brake pedal 4 after a period of time.

[0055] See Figure 9 In steps S102 and S104, when the driver releases the accelerator pedal 3 and immediately depresses the brake pedal 4 (step S102), the preset braking torque is obtained by the control module 1 through braking torque superposition calculation based on the braking torque correspondence table (step S104). The braking torque correspondence table represents the correspondence between the braking torque setting percentage and the braking torque value. When the driver releases the accelerator pedal 3 and immediately depresses the brake pedal 4, the electric motor assembly 2 immediately switches from outputting positive torque to outputting reverse torque, i.e., braking torque. At this time, the control module 1 calculates the preset braking torque value to be output based on the braking torque setting percentage set by the driver according to the braking torque correspondence table. Then, the control module 1 performs superposition calculation on the braking torque by looking up a table (torque change correspondence table) and controls the electric motor assembly 2 to continuously correct the braking torque until the corrected braking torque equals the preset braking torque value obtained from the braking torque correspondence table before outputting it.

[0056] In detail, when the driver releases the accelerator pedal 3 and then presses the brake pedal 4 after a period of time (step S101), the electric motor assembly 2 has already output the current braking torque since the accelerator pedal 3 has been released for a period of time (step S103). At this time, the control module 1 compares the current braking torque with the target braking torque obtained by the control module 1 according to the braking torque correspondence table to determine whether the current braking torque is less than the target braking torque (step S105).

[0057] If the control module 1 determines that the current braking torque is not less than (i.e., greater than or equal to) the target braking torque, then the current braking torque is the preset braking torque (step S109). In other words, the current braking torque does not need to be corrected, and the motor assembly 2 directly outputs the current braking torque as the preset braking torque.

[0058] On the other hand, if the control module 1 determines that the current braking torque is less than the target braking torque, the control module 1 performs a braking torque superposition calculation based on the braking torque correspondence table to control the motor assembly 2 to correct the current braking torque so that it equals the target braking torque. The target braking torque is then the preset braking torque (step S107). Specifically, the control module 1 calculates the preset braking torque value to be output based on the braking torque setting percentage set by the driver, according to the braking torque correspondence table. Then, the control module 1 performs a superposition calculation on the braking torque using a lookup table (torque change correspondence table), and controls the motor assembly 2 to continuously correct the braking torque until the corrected braking torque equals the preset braking torque value obtained from the braking torque correspondence table before outputting it.

[0059] Beneficial effects of the embodiments

[0060] The torque control system for electric vehicles provided by this invention controls the output torque of the electric vehicle by issuing acceleration control commands. The driver only needs to determine different target accelerations to calculate the most appropriate torque command value required by the vehicle at that moment. Therefore, it can significantly reduce the number of calibration tables stored in the system, reduce calibration time, and reduce the amount of in-vehicle memory used. Furthermore, since the output torque of the electric vehicle is adjusted and calculated according to the overall vehicle acceleration, it can reduce the impact of road surface changes, slopes, and vehicle load during vehicle operation. The driver no longer needs to frequently press the accelerator pedal according to road conditions, which helps to reduce the complexity of vehicle operation.

[0061] Furthermore, in existing technologies, the braking torque corresponding to the regenerative braking calibration level of electric vehicles is set by the vehicle manufacturer, and the driver can only select but not freely adjust to the desired braking torque value. In contrast, the electric vehicle torque control system of this invention provides stepless braking torque setting, allowing the driver to adjust the desired braking torque value according to personal preference. In other words, the braking torque required for energy recovery by the electric vehicle torque control system of this invention is calculated by the system, rather than being a pre-designed calibration parameter.

[0062] Therefore, the braking torque required for energy recovery in the electric vehicle torque control system of this invention can be appropriately adjusted based on the calculation results, achieving stepless switching of energy recovery. For example, when the electric vehicle decelerates for energy recovery on a downhill section, the vehicle will not experience different deceleration sensations due to differences in vehicle load and road slope, allowing the driver to experience selectable ride comfort. Furthermore, because the electric vehicle torque control system of this invention can freely adjust the braking torque for energy recovery, it can achieve maximum energy recovery while maintaining ride comfort, thus improving the overall vehicle energy consumption performance.

Claims

1. A torque control system for an electric vehicle, characterized in that, The torque control system of the electric vehicle comprises: an accelerator pedal; a brake pedal; an electric motor assembly electrically connected to the accelerator pedal and the brake pedal, the electric motor assembly being configured to output a forward torque; and a control module electrically connected to the electric motor assembly, the accelerator pedal and the brake pedal, the control module being configured to: obtain an actual vehicle speed of the electric vehicle and a pedal opening of the accelerator pedal, and determine a target acceleration of the electric vehicle based on the actual vehicle speed and the pedal opening; calculate a difference between the target acceleration and a longitudinal acceleration of the electric vehicle, to obtain an acceleration difference; determine a torque variation based on the acceleration difference and the actual vehicle speed; and perform a torque superposition calculation on the forward torque based on the torque variation, and control the electric motor assembly to correct the forward torque based on a result of the torque superposition calculation.

2. The torque control system of an electric vehicle according to claim 1, characterized by, In the step of obtaining the vehicle speed of the electric vehicle and the pedal opening of the accelerator pedal, and determining the target acceleration of the electric vehicle based on the vehicle speed and the pedal opening, the control module is further configured to: select an acceleration corresponding relationship table corresponding to a current driving mode, wherein the acceleration corresponding relationship table comprises a corresponding relationship among the vehicle speed of the electric vehicle, the pedal opening of the accelerator pedal and the target acceleration; and determine the target acceleration corresponding to the current vehicle speed and the current pedal opening from the acceleration corresponding relationship table. In the step of determining the torque variation based on the acceleration difference and the vehicle speed, the control module is further configured to:

3. The torque control system of claim 2, wherein select a torque variation corresponding relationship table corresponding to the current driving mode, wherein the torque variation corresponding relationship table comprises a corresponding relationship among the vehicle speed of the electric vehicle, the acceleration difference and the torque variation; and determine the torque variation corresponding to the current vehicle speed and the acceleration difference from the torque variation corresponding relationship table. In the step of performing the torque superposition calculation on the forward torque based on the torque variation, and controlling the electric motor assembly to correct the forward torque based on a result of the torque superposition calculation, the control module is further configured to: output a predetermined forward torque via the torque superposition calculation; and 4. The torque control system of claim 3, wherein, determine that the predetermined forward torque is within a torque limit range. The predetermined forward torque being within the torque limit range means that the predetermined forward torque is greater than a lower limit value and less than an upper limit value; wherein the upper limit value is equal to a maximum forward torque that the electric motor assembly can output, and the lower limit value is equal to an absolute value of a preset brake torque output by the electric motor assembly. When the driver releases the accelerator pedal and does not step on the brake pedal, the preset brake torque is obtained by multiplying a maximum brake torque that the electric motor assembly can output by a brake torque setting percentage.

5. The torque control system of claim 4, wherein, The brake torque setting percentage is any value in a range from 0 to 100%.

6. The torque control system of claim 5, wherein, The brake torque setting percentage is set by the driver through a vehicle information system of the electric vehicle.

7. The torque control system of claim 6, wherein, When the driver releases the accelerator pedal and immediately steps on the brake pedal, the preset brake torque is obtained by performing a brake torque superposition calculation by the control module based on a brake torque corresponding relationship table.

8. The torque control system of claim 6, wherein, ​ 9. The torque control system of the electric vehicle according to claim 5, wherein, ​ 10. The torque control system of claim 5, wherein, When the driver releases the accelerator pedal for a period of time and then steps on the brake pedal, the motor assembly outputs a current brake torque, wherein: If the current brake torque is greater than or equal to a target brake torque obtained by the control module according to a brake torque corresponding relationship table, the current brake torque is the preset brake torque; If the current brake torque is less than the target brake torque obtained by the control module according to the brake torque corresponding relationship table, the control module performs brake torque superposition calculation according to a brake torque setting percentage and the brake torque corresponding relationship table to control the motor assembly to correct the current brake torque so that it is equal to the target brake torque, and the target brake torque is the preset brake torque.

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