Torque distribution methods in electric vehicles and electric vehicles

Abstract

This application provides a torque distribution method for an electric vehicle and an electric vehicle itself. When the electric vehicle is in a forward-moving state, torque is distributed to a first motor and a second motor according to a first torque distribution relationship. The first torque distribution relationship is the correspondence between the vehicle speed, torque, and the torque distributed by the first and second motors when the total efficiency of the first and second motors is at its highest. The torque distributed by the first and second motors is either all positive or all negative. When the electric vehicle is not in a forward-moving state, torque is distributed to the first and second motors according to a second torque distribution relationship. The second torque distribution relationship is the correspondence between the vehicle speed, torque, and the torque distributed by the first and second motors when the total efficiency of the first and second motors is at its highest. The torque distributed by the first and second motors includes both positive and negative torque. This application can improve the efficiency of the electric vehicle's power system.

Description

Technical Field

[0001] This application relates to the field of automotive control technology, and more particularly to a torque distribution method for an electric vehicle and the electric vehicle itself. Background Technology

[0002] For dual-axle drive electric vehicles, the torque distribution between the two motors directly affects the vehicle's driving range and energy consumption. In actual operation, the motor's efficiency changes dynamically with factors such as vehicle speed and required torque. An unreasonable torque distribution may cause some motors to operate in the inefficient range for extended periods, wasting energy and affecting the overall vehicle's power performance.

[0003] Existing torque distribution methods typically distribute the required torque evenly among the two motors. This distribution method is simple and easy to implement, but it cannot guarantee that both motors will operate in the high-efficiency range, nor can it guarantee that the overall efficiency of the two motors will be maximized, thus increasing the energy consumption of electric vehicles. Summary of the Invention

[0004] This application provides a high-efficiency torque distribution method for electric vehicles and an electric vehicle.

[0005] This application provides a torque distribution method for an electric vehicle, the electric vehicle including a first motor and a second motor, the torque distribution method including:

[0006] The driving status, current speed, and required torque of the electric vehicle are obtained; the driving status includes forward movement and non-forward movement.

[0007] When the electric vehicle is in the forward state, torque is allocated to the first motor and the second motor through a first torque allocation relationship. The first torque allocation relationship is the correspondence between the vehicle speed, torque and the torque allocated to the first motor and the second motor when the total efficiency of the first motor and the second motor is the highest. The torque allocated to the first motor and the second motor is either both positive torque or both negative torque.

[0008] When the electric vehicle is in the non-forward state, torque is allocated to the first motor and the second motor through a second torque allocation relationship. The second torque allocation relationship is the correspondence between the vehicle speed, torque and the torque allocated to the first motor and the second motor when the total efficiency of the first motor and the second motor is at its highest. The torque allocated to the first motor and the second motor includes positive torque and negative torque.

[0009] Optionally, when the electric vehicle is in the forward state, distributing torque to the first motor and the second motor through a first torque distribution relationship includes:

[0010] When the electric vehicle is in the forward state, the current vehicle speed and the required torque are substituted into the first torque distribution relationship to obtain the corresponding torque distribution coefficient; the torque distribution coefficient is the ratio of the torque distributed by the first motor to the required torque;

[0011] According to the torque distribution coefficient, torque is distributed to the first motor and the second motor;

[0012] The first torque distribution relationship is: the correspondence between the vehicle speed, torque and torque distribution coefficient of the electric vehicle when the total efficiency of the first motor and the second motor is at its highest; the torque distribution coefficient indicates whether the torque distributed by the first motor and the second motor is either positive or negative.

[0013] Optionally, when the electric vehicle is in the forward state, substituting the current vehicle speed and the required torque into the first torque distribution relationship to obtain the corresponding torque distribution coefficient includes:

[0014] When the electric vehicle is in the forward state for a preset time, the current vehicle speed and the required torque are substituted into the first torque distribution relationship to obtain the corresponding torque distribution coefficient.

[0015] Optionally, distributing torque to the first motor and the second motor according to the torque distribution coefficient includes:

[0016] According to the torque distribution coefficient, the first torque allocated to the first motor and the second torque allocated to the second motor are determined;

[0017] The output torque of the first motor is controlled to gradually reach the first torque, and the output torque of the second motor is controlled to gradually reach the second torque.

[0018] Optionally, controlling the output torque of the first motor to gradually reach the first torque, and controlling the output torque of the second motor to gradually reach the second torque, includes:

[0019] The output torque of the first motor is controlled to gradually increase or decrease by a preset torque value until the first torque is reached, and the output torque of the second motor is controlled to gradually increase or decrease by the preset torque value until the second torque is reached.

[0020] Optionally, the first torque distribution relationship is determined through the following steps:

[0021] Obtain the maximum speed of the electric vehicle;

[0022] Based on the maximum vehicle speed and the external characteristic curves of the first motor and the second motor, the minimum allowable torque and the maximum allowable torque that the first motor and the second motor are allowed to output when the vehicle speed of the electric vehicle is less than the maximum vehicle speed are determined. The minimum allowable torque is the sum of the minimum allowable torques of the first motor and the second motor, and the maximum allowable torque is the sum of the maximum allowable torques of the first motor and the second motor.

[0023] According to the first preset step size, the vehicle speed of the electric vehicle is grouped within the range of zero to the maximum vehicle speed, and the torque is grouped within the range of minimum allowable torque to maximum allowable torque;

[0024] The grouped electric vehicles are arranged and combined according to their speed and torque.

[0025] The torque distribution coefficients are grouped within a range of 0 to 1 according to a second preset step size.

[0026] For each set of vehicle speed and torque, calculate the total efficiency of the first motor and the second motor corresponding to each set of torque distribution coefficient;

[0027] The first torque distribution relationship exists between each group of vehicle speeds, torques, and the torque distribution coefficient corresponding to the highest overall efficiency.

[0028] Optionally, when the electric vehicle is in the non-forward state, distributing torque to the first motor and the second motor through a second torque distribution relationship includes:

[0029] When the electric vehicle is in the non-forward state, the current vehicle speed and the required torque are substituted into the second torque distribution relationship to obtain the corresponding distributed torque; the distributed torque is the torque allocated to the first motor.

[0030] According to the allocated torque, torque is allocated to the first motor and the second motor;

[0031] The second torque distribution relationship is: the correspondence between the vehicle speed, torque and distributed torque of the electric vehicle when the total efficiency of the first motor and the second motor is at its highest; the distributed torque refers to the torque distributed by the first motor and the second motor, including positive torque and negative torque.

[0032] Optionally, the second torque distribution relationship is determined through the following steps:

[0033] Obtain the maximum speed of the electric vehicle;

[0034] Based on the maximum vehicle speed and the external characteristic curves of the first motor and the second motor, determine the maximum allowable torque and the minimum allowable torque that the first motor and the second motor are allowed to output when the vehicle speed of the electric vehicle is less than the maximum vehicle speed. The maximum allowable torque is the sum of the maximum allowable torques of the first motor and the second motor, and the minimum allowable torque is the sum of the minimum allowable torques of the first motor and the second motor.

[0035] According to the first preset step size, the vehicle speed of the electric vehicle is grouped within the range of zero to the maximum vehicle speed, and the torque is grouped within the range of minimum allowable torque to maximum allowable torque;

[0036] The grouped electric vehicles are arranged and combined according to their speed and torque.

[0037] Based on the maximum vehicle speed, determine the maximum and minimum torque that the first motor is allowed to output;

[0038] According to the second preset step size, the allocated torque is grouped within the range from the minimum allowable output torque of the first motor to the maximum allowable output torque;

[0039] For each set of vehicle speed and torque, calculate the total efficiency of the first motor and the second motor corresponding to each set of allocated torque;

[0040] The second torque distribution relationship exists between each group of vehicle speeds, torques, and the allocated torque corresponding to the highest overall efficiency.

[0041] This application also provides a torque distribution device for an electric vehicle, including one or more processors for implementing the torque distribution method for an electric vehicle as described in any of the preceding claims.

[0042] This application also provides an electric vehicle, including:

[0043] First motor;

[0044] Second motor; and

[0045] The torque distribution device described above is electrically connected to the first motor and the second motor.

[0046] In some embodiments, when the electric vehicle is in a forward-moving state, torque is allocated to the first motor and the second motor according to a first torque distribution relationship. In the first torque distribution relationship, the torque allocated to the first motor and the second motor is either both positive torque or both negative torque, thereby maximizing the overall efficiency of the first motor and the second motor. When the electric vehicle is not in a forward-moving state, torque is allocated to the first motor and the second motor according to a second torque distribution relationship. In the second torque distribution relationship, the torque allocated to the first motor and the second motor includes both positive and negative torque, thereby maximizing the overall efficiency of the first motor and the second motor. When the electric vehicle is in a forward-moving state, one motor is allowed to output positive torque and the other motor to output negative torque. However, when the electric vehicle is not in a forward-moving state, both motors need to output either positive or negative torque. By allocating torque according to different torque distribution relationships based on the state of the electric vehicle, the overall efficiency of the first motor and the second motor can be kept at its highest regardless of the state of the electric vehicle, thereby improving the efficiency of the electric vehicle's power system and reducing energy consumption.

[0047] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0048] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0049] Figure 1 The diagram shown is a schematic representation of an embodiment of the electric vehicle of this application.

[0050] Figure 2 The diagram shown is a flowchart of one embodiment of the torque distribution method for electric vehicles according to this application.

[0051] Figure 3 The diagram shown is a structural block diagram of one embodiment of the torque distribution device of this application. Detailed Implementation

[0052] This application provides a torque distribution method for an electric vehicle and the electric vehicle itself. The torque distribution method and the electric vehicle of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0053] Figure 1 The diagram shown is a schematic representation of one embodiment of the electric vehicle 10 of this application. Figure 1 As shown, the electric vehicle 10 includes: a first motor 11, a second motor 12, and a torque distribution device 13.

[0054] The electric vehicle 10 includes a front axle and a rear axle. Figure 1 In the illustrated embodiment, the first motor 11 is located on the front axle of the electric vehicle 10, and the second motor 12 is located on the rear axle of the electric vehicle 10. The first motor 11 is a front-drive motor, and the second motor 12 is a rear-drive motor. In other embodiments, the first motor 11 is located on the rear axle of the electric vehicle 10, and the second motor 12 is located on the front axle of the electric vehicle 10.

[0055] The electric vehicle 10 operates in several modes, including forward and non-forward modes. Non-forward modes include steering and reversing modes. When the vehicle is in forward mode, the dual-axle powertrain can drive or brake on both axles simultaneously, drive or brake on a single axle, or drive on one axle while braking on the other. When the vehicle is in non-forward mode, the dual-axle motor cannot drive or brake on one axle.

[0056] The torque distribution device 13 is electrically connected to the first motor 11 and the second motor 12, and is used to implement the torque distribution method for the electric vehicle provided in this application. The torque distribution device 13 is used to distribute torque to the first motor 11 and the second motor 12. The torque distribution device 13 may include a first motor controller and a second motor controller, the first motor controller being electrically connected to the first motor 11 and the second motor controller being electrically connected to the second motor 12. The torque distribution device 13 may also be the VCU (Vehicle Control Unit) and / or TCU (Transmission Control Unit) of the electric vehicle 10. In some embodiments, the VCU determines the required torque of the vehicle and sends it to the TCU, which then performs torque distribution.

[0057] Figure 2 The diagram shown is a flowchart of one embodiment of the torque distribution method 20 for electric vehicles according to this application. Figure 2 As shown, the torque distribution method 20 for electric vehicles includes steps 21 to 24.

[0058] Step 21: Obtain the driving status, current speed, and required torque of the electric vehicle.

[0059] Driving status includes forward and non-forward states. The electric vehicle 10 includes various sensors, such as wheel speed sensors, steering angle sensors, acceleration sensors, and gear position sensors. The torque distribution device 13 can obtain the driving status of the electric vehicle based on signals from these sensors. For example, by combining data from the gear position sensor and wheel speed sensors, it can be determined whether the vehicle is in a forward or reverse (non-forward) state. By combining data from the steering angle sensor and wheel speed sensors, it can be determined whether the vehicle is turning. The current vehicle speed can be obtained through the wheel speed sensors. The required torque of the vehicle can be obtained through the accelerator pedal position sensor, brake pedal position sensor, and gear position sensor.

[0060] Step 22: Determine the driving status of the electric vehicle.

[0061] Based on the driving status of the electric vehicle obtained in step 21, different measures are taken when the electric vehicle is in a forward-moving state and not in a forward-moving state.

[0062] Step 23: When the electric vehicle is in a forward-moving state, torque is distributed to the first motor and the second motor through the first torque distribution relationship.

[0063] The first torque distribution relationship is the correspondence between the vehicle speed, torque, and the torque allocated to the first and second motors when the total efficiency of the first and second motors is at its highest. The torque allocated to both the first and second motors can be either positive or negative. This first torque distribution relationship ensures that the total efficiency of the first and second motors is maximized. It is a pre-determined distribution relationship obtained through experiments or experience. The first torque distribution relationship is stored in the torque distribution device 13. When the vehicle's driving state is detected as forward, the current vehicle speed and required torque are substituted into the first torque distribution relationship to obtain the torque allocated to the first and second motors corresponding to the current vehicle speed and required torque. Thus, when the vehicle is in a forward state, the total efficiency of the first and second motors is maximized, improving the efficiency of the vehicle's power system and reducing energy consumption.

[0064] Step 24: When the electric vehicle is not moving forward, torque is distributed to the first motor and the second motor through the second torque distribution relationship.

[0065] The second torque distribution relationship is the correspondence between the vehicle speed, torque, and the torque allocated to the first and second motors when the total efficiency of the first and second motors is at its highest. The torque allocated to the first and second motors includes both positive and negative torque. This second torque distribution relationship ensures that the total efficiency of the first and second motors is maximized. It is a pre-determined distribution relationship obtained through experiments or experience. The second torque distribution relationship is stored in the torque distribution device 13. When the vehicle's driving state is detected as non-forward, the current vehicle speed and required torque are substituted into the second torque distribution relationship to obtain the torque allocated to the first and second motors corresponding to the current vehicle speed and required torque. Thus, when the vehicle is in a non-forward state, the total efficiency of the first and second motors is maximized, improving the efficiency of the vehicle's power system and reducing energy consumption.

[0066] In the first torque distribution relationship and the second torque distribution relationship, for the same vehicle's current speed and required torque, the torque allocated to the first motor and the second motor can be the same or different.

[0067] When an electric vehicle is moving forward, one motor is allowed to output positive torque while the other outputs negative torque. However, when the electric vehicle is not moving forward, both motors need to output either positive or negative torque. Depending on the driving state of the electric vehicle, the torque allocated to the two motors may differ when the overall efficiency of the two motors is at its peak. When the electric vehicle is moving forward, and the overall efficiency of the powertrain is at its peak, both motors may output positive or negative torque, or one motor may output positive torque while the other outputs negative torque. When the electric vehicle is not moving forward, and the overall efficiency of the powertrain is at its peak, both motors may output positive or negative torque, but one motor cannot output positive torque while the other outputs negative torque. Therefore, if the same torque distribution relationship is applied to different driving states of the vehicle, it cannot be guaranteed that the powertrain efficiency will be maximized regardless of the vehicle's driving state.

[0068] By distributing torque according to different torque distribution relationships based on the state of the electric vehicle, the total efficiency of the first and second motors can be kept at its highest regardless of the state of the electric vehicle, which can improve the efficiency of the electric vehicle's power system and reduce energy consumption.

[0069] In some embodiments, step 23 includes: when the electric vehicle is in a forward state, substituting the current vehicle speed and required torque into a first torque distribution relationship to obtain a corresponding torque distribution coefficient; the torque distribution coefficient is the ratio of the torque allocated by the first motor to the required torque; according to the torque distribution coefficient, allocating torque to the first motor and the second motor; the first torque distribution relationship is: the correspondence between the vehicle speed, torque and torque distribution coefficient of the electric vehicle when the total efficiency of the first motor and the second motor is the highest; the torque distribution coefficient indicates that the torque allocated by the first motor and the second motor is either both positive torque or both negative torque.

[0070] When an electric vehicle is moving forward, the first and second motors can drive or brake simultaneously, meaning the torque allocated to both motors is either positive or negative. The first torque allocation relationship can be obtained experimentally or empirically. For example, for different vehicle speeds and required torques, the total efficiency of the first and second motors corresponding to different torque allocation coefficients can be calculated. The torque allocation coefficient corresponding to the highest total efficiency is then used as the torque allocation coefficient for that set of vehicle speeds and required torques, forming the first torque allocation relationship. Substituting the current vehicle speed and required torque into the first torque allocation relationship, the corresponding torque allocation coefficient can be obtained through methods such as table lookup and interpolation. For example, based on the current vehicle speed range and the required torque range, the corresponding torque allocation coefficient can be found in the first torque allocation relationship. In this way, torque can be easily and quickly allocated to the first and second motors to maximize overall efficiency.

[0071] In some embodiments, when the electric vehicle is in a forward state, substituting the current vehicle speed and the required torque into the first torque distribution relationship to obtain the corresponding torque distribution coefficient includes: when the electric vehicle is in a forward state for a preset time, substituting the current vehicle speed and the required torque into the first torque distribution relationship to obtain the corresponding torque distribution coefficient.

[0072] When an electric vehicle is moving forward, torque is not immediately distributed to the first and second motors according to the initial torque distribution relationship. Instead, torque distribution is performed only after the electric vehicle has been moving forward for a preset period of time. This prevents excessively frequent torque changes and improves the driving experience. The preset period can be calibrated according to the vehicle model or application scenario.

[0073] In some embodiments, allocating torque to the first motor and the second motor according to the torque allocation coefficient includes: determining the first torque allocated to the first motor and the second torque allocated to the second motor according to the torque allocation coefficient; controlling the output torque of the first motor to gradually reach the first torque, and controlling the output torque of the second motor to gradually reach the second torque.

[0074] In some embodiments, the time for the first motor to reach a first torque and the time for the second motor to reach a second torque are fixed values, during which the motor output torque is gradually converted into the target torque of the motor. In other embodiments, the step size of the motor output torque is fixed, and the motor output torque gradually reaches the target torque of the motor according to this step size.

[0075] In actual control, the rate of change of the motor's output torque can be detected in real time. If the rate of change exceeds a threshold, the motor's output torque is controlled to slow down the change, varying according to a preset step size. This prevents excessively frequent torque changes in the vehicle, extends the motor's lifespan, and improves the driving experience.

[0076] In some embodiments, controlling the output torque of the first motor to gradually reach a first torque and controlling the output torque of the second motor to gradually reach a second torque includes: controlling the output torque of the first motor to gradually increase or decrease a preset torque value until the first torque is reached, and controlling the output torque of the second motor to gradually increase or decrease a preset torque value until the second torque is reached.

[0077] The preset torque value indicates the magnitude of each adjustment. The preset torque value can be reasonably set based on the motor's performance parameters (such as maximum power, maximum torque, torque response speed, etc.), the vehicle's driving conditions (e.g., a smaller preset torque value at low speeds and a larger preset torque value at high speeds), and the accuracy requirements of the control system. If the preset torque value is set too large, it may cause excessively drastic adjustments to the motor's output torque, leading to unstable vehicle power output and even impacting the motor and vehicle's transmission system. If the preset torque value is set too small, although the adjustment process will be smoother, it may result in excessively long adjustment times, affecting the vehicle's real-time response to power demands.

[0078] If the current torque of the motor is greater than its target torque, the output torque of the motor is gradually reduced by a preset torque value until it reaches the target torque. If the current torque of the motor is less than its target torque, the output torque of the motor is gradually increased by a preset torque value until it reaches the target torque. In this way, the output torque of the motor can transition to the target value more smoothly, avoiding the adverse effects of sudden torque changes on the vehicle's power system and driving stability, and improving driving comfort.

[0079] In some embodiments, the first torque distribution relationship is determined through the following steps: obtaining the maximum speed of the electric vehicle; determining, based on the maximum speed and the external characteristic curves of the first and second motors, the minimum and maximum allowable torques that the first and second motors are allowed to output when the electric vehicle speed is less than the maximum speed, wherein the minimum allowable torque is the sum of the minimum allowable torques of the first and second motors, and the maximum allowable torque is the sum of the maximum allowable torques of the first and second motors; grouping the electric vehicle speeds within the range from zero to the maximum speed according to a first preset step size, and grouping the torques within the range from the minimum allowable torque to the maximum allowable torque; arranging and combining the grouped electric vehicle speeds and torques; grouping the torque distribution coefficients within the range from 0 to 1 according to a second preset step size; calculating the total efficiency of the first and second motors corresponding to each group of speeds and torques, respectively; and establishing a first torque distribution relationship between each group of speeds, torques, and the torque distribution coefficient corresponding to the highest total efficiency.

[0080] The torque distribution factor indicates how the required torque is allocated between the first and second motors. For example, if the required torque is 100 N·m, and the first motor receives 30 N·m of torque, then the torque distribution factor is 0.3. To ensure that the first and second motors output positive or negative torque simultaneously, the torque distribution factor ranges from [0, 1].

[0081] The maximum speed can be found by consulting the vehicle's technical manual.

[0082] The external characteristic curves of the first and second motors reflect the output capabilities of the motors under different operating conditions (such as different speeds), including the relationship between output torque and speed. By analyzing the external characteristic curves and combining them with the maximum vehicle speed, the allowable torque range of the first and second motors can be determined under all possible operating conditions where the vehicle speed is less than the maximum vehicle speed.

[0083] The relationship between the total efficiency of the first motor and the second motor, the torque distribution coefficient, the vehicle speed, and the required torque can be expressed by formulas (1) to (7).

[0084] η=(P fmec +P rmec ) / (P fele +P rele ) Formula (1)

[0085] P fmec =P fele *η fmec Formula (2)

[0086] P rmec =P rele *ηrmec Formula (3)

[0087] P fmec +P rmec =[n f (1-λ)T+n r Formula (4) is represented by [*λ*T] / 9550.

[0088] P fele +P rele =[η rmec *n f (1-λ)T+η fmec *n r λT] / (9550*η fmec *η rmec ) Formula (5)

[0089] v=0.12πrn / i Formula (6)

[0090] η={η f *η r [i f (1-λ)T+i r *λ*T]} / (η r *i f (1-λ)T+η f *i r Formula (7)

[0091] Where η is the overall efficiency, P fmec P is the mechanical power of the first motor. rmec P is the mechanical power of the second motor. fele P is the bus input power of the first motor. rele η is the bus input power of the second motor. fmec η is the efficiency of the first motor. rmec Let T be the efficiency of the second motor, T be the required torque, and n be the torque. f The first motor speed, n r Let λ be the speed of the second motor, λ be the torque distribution coefficient, v be the vehicle speed, r be the tire radius, and i be the reduction ratio. f i is the front axle reduction ratio. r This is the rear axle reduction ratio.

[0092] By substituting the vehicle speed, required torque, and different torque distribution coefficients into formula (7), we can obtain the total efficiency corresponding to different torque distribution coefficients under the current vehicle speed and required torque.

[0093] In determining the torque distribution coefficient with the highest overall efficiency, the vehicle speed, torque, and torque distribution coefficient are first divided into grids. For example, if the first preset step size is set to 10 km / h and the maximum vehicle speed is 120 km / h, then the grid points for vehicle speed are [10, 20, ... 110, 120]. The allowable torque output range of the first motor is [-200, 200], and the allowable torque output range of the second motor is [-300, 300]. Therefore, the range from the minimum allowable torque to the maximum allowable torque is [-500, 500], and the torque grid points are [-500, -490, ... 490, 500]. For the grouped vehicle speed and torque combinations, all possible combinations are enumerated, each representing a working condition that the vehicle might encounter during actual driving. In some embodiments, the rotational speeds of the first and second motors can be determined based on the vehicle speed. Using the external characteristic curves of the motors, the maximum motor torque corresponding to the current rotational speed can be obtained, thereby eliminating torque combinations that cannot be corresponding to the vehicle speed and reducing computational complexity. If the second preset step size is set to 0.1, then the torque distribution coefficient grid points are [0, 0.1, 0.2, ... 0.9, 1].

[0094] For each combination of vehicle speed and torque conditions, the total efficiency of the first and second motors corresponding to each torque distribution coefficient is calculated. That is, under each vehicle speed and torque condition, the above 10 different torque distribution schemes are considered. Substituting the vehicle speed, torque, and torque distribution coefficient into formula (7), the corresponding total efficiency can be obtained. For example, under the condition of vehicle speed of 60km / h and torque of 120N·m, when the torque distribution coefficient is 0.2, the total efficiency of the first and second motors is calculated to be 80%; when the torque distribution coefficient is 0.3, the total efficiency is 82%, etc.

[0095] For each vehicle speed and torque condition, identify the torque distribution coefficient that maximizes overall efficiency. This establishes a primary torque distribution relationship between each set of vehicle speeds, torques, and the torque distribution coefficient corresponding to the highest overall efficiency. This primary torque distribution relationship can be presented in the form of a table, curve, or mathematical model.

[0096] The above method can quickly and accurately determine the first torque distribution relationship, thereby improving the overall efficiency of the vehicle during operation.

[0097] In some embodiments, step 24 includes: when the electric vehicle is in a non-forward state, substituting the current vehicle speed and required torque into the second torque distribution relationship to obtain the corresponding distributed torque; the distributed torque is the torque allocated to the first motor; according to the distributed torque, the torque is allocated to the first motor and the second motor; the second torque distribution relationship is: the correspondence between the vehicle speed, torque and distributed torque of the electric vehicle when the total efficiency of the first motor and the second motor is the highest; the distributed torque indicates that the torque allocated to the first motor and the second motor includes positive torque and negative torque.

[0098] When an electric vehicle is not moving forward, the first and second motors can drive or brake simultaneously, or one motor can drive while the other brakes. This means the torque allocated to the first and second motors can be positive or negative. The second torque allocation relationship can be obtained experimentally or empirically. For example, for different vehicle speeds and required torques, the total efficiency of the first and second motors corresponding to different allocated torques can be calculated. The allocated torque corresponding to the highest total efficiency is then used as the allocated torque for that set of vehicle speeds and required torques, forming the second torque allocation relationship. Substituting the current vehicle speed and required torque into the second torque allocation relationship, the corresponding allocated torque can be obtained through methods such as table lookup and interpolation. For example, based on the current vehicle speed range and the required torque range, the corresponding allocated torque can be found in the second torque allocation relationship. In this way, torque can be easily and quickly allocated to the first and second motors to maximize overall efficiency.

[0099] In some embodiments, the second torque distribution relationship is determined through the following steps: obtaining the maximum speed of the electric vehicle; determining, based on the maximum speed and the external characteristic curves of the first and second motors, the maximum and minimum allowable torques that the first and second motors are allowed to output when the electric vehicle speed is less than the maximum speed, wherein the maximum allowable torque is the sum of the maximum allowable torques of the first and second motors, and the minimum allowable torque is the sum of the minimum allowable torques of the first and second motors; grouping the electric vehicle speeds within the range from zero to the maximum speed according to a first preset step size, and grouping the torques within the range from the minimum to the maximum allowable torque; arranging and combining the grouped electric vehicle speeds and torques; determining the maximum and minimum allowable torques that the first motor is allowed to output according to the maximum speed; grouping the allocated torques within the range from the minimum to the maximum allowable torques of the first motor according to a second preset step size; calculating the total efficiency of the first and second motors corresponding to each group of speeds and torques; and establishing a second torque distribution relationship between each group of speeds, torques, and the allocated torque corresponding to the highest total efficiency.

[0100] The relationship between the total efficiency of the first motor and the second motor, the distributed torque of the first motor, the distributed torque of the second motor, the vehicle speed, and the required torque can be expressed by formula (8).

[0101] η=(η f *i f *T f +η r *v*i r *T r ) / (i f *T f +i r *T r ) Formula (8)

[0102] Among them, T f T is the torque assigned to the first motor. r The torque allocated to the second motor.

[0103] The process of dividing the vehicle speed and required torque into a grid can be referred to above. Obtain the minimum and maximum torque of the first motor, and divide the allocated torque into a grid according to the second preset step size. For example, if the allowable output torque range of the first motor is [-200, 200], the second preset step size is 10 N·m, and the grid points for the allocated torque are [-200, -190, -180, ... 190, 200].

[0104] For each combination of vehicle speed and torque conditions, calculate the total efficiency of the first motor and the second motor corresponding to each set of distributed torque. Substituting the vehicle speed, torque, and distributed torque into formula (8), the corresponding total efficiency can be obtained.

[0105] For each vehicle speed and torque condition, identify the torque distribution that maximizes overall efficiency. A second torque distribution relationship is then established between each set of vehicle speeds, torques, and the torque distribution corresponding to the highest overall efficiency. This second torque distribution relationship can be presented in the form of a table, curve, or mathematical model.

[0106] Using the above method, the second torque distribution relationship can be determined relatively quickly and accurately, thereby improving the overall efficiency of the vehicle during operation.

[0107] In some embodiments, the torque distribution method 20 further includes: when one of the first motor and the second motor outputs positive torque and the other outputs negative torque, if the sum of the absolute values ​​of the torques output by the first motor and the second motor is greater than a torque threshold, controlling the first motor and the second motor to output torque in the same direction according to the required torque. This prevents excessive stretching of the vehicle chassis and improves vehicle safety.

[0108] Figure 3 The diagram shown is a structural block diagram of one embodiment of the torque distribution device of this application.

[0109] like Figure 3 As shown, the torque distribution device includes one or more processors 31 for implementing the torque distribution method 20 of the electric vehicle as described above.

[0110] In some embodiments, the torque distribution device may include a computer-readable storage medium 32, which may store a program that can be invoked by a processor 31, and may include a non-volatile storage medium. In some embodiments, the torque distribution device may include memory 33 and an interface 34. In some embodiments, the torque distribution device may also include other hardware depending on the specific application.

[0111] The computer-readable storage medium 32 of this application embodiment stores a program that, when executed by the processor 31, is used to implement the torque distribution method 20 of the electric vehicle as described above.

[0112] This application may take the form of a computer program product implemented on one or more computer-readable storage media 32 (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing program code. The computer-readable storage media 32 includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented using any method or technology. The information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media 32 include, but are not limited to: phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

Claims

1. A torque distribution method for an electric vehicle, characterized in that, The electric vehicle includes a first motor and a second motor, and the torque distribution method includes: The driving status, current speed, and required torque of the electric vehicle are obtained; the driving status includes forward movement and non-forward movement. When the electric vehicle is in the forward state, torque is allocated to the first motor and the second motor through a first torque allocation relationship. The first torque allocation relationship is the correspondence between the vehicle speed, torque and the torque allocated to the first motor and the second motor when the total efficiency of the first motor and the second motor is the highest. The torque allocated to the first motor and the second motor is either both positive torque or both negative torque. When the electric vehicle is in the non-forward state, torque is allocated to the first motor and the second motor through a second torque allocation relationship. The second torque allocation relationship is the correspondence between the vehicle speed, torque and the torque allocated to the first motor and the second motor when the total efficiency of the first motor and the second motor is at its highest. The torque allocated to the first motor and the second motor includes positive torque and negative torque.

2. The torque distribution method for an electric vehicle according to claim 1, characterized in that, When the electric vehicle is in the forward state, the process of allocating torque to the first motor and the second motor according to the current vehicle speed and the required torque through a first torque distribution relationship includes: When the electric vehicle is in the forward state, the current vehicle speed and the required torque are substituted into the first torque distribution relationship to obtain the corresponding torque distribution coefficient; the torque distribution coefficient is the ratio of the torque distributed by the first motor to the required torque; According to the torque distribution coefficient, torque is distributed to the first motor and the second motor; The first torque distribution relationship is: the correspondence between the vehicle speed, torque and torque distribution coefficient of the electric vehicle when the total efficiency of the first motor and the second motor is at its highest; the torque distribution coefficient indicates whether the torque distributed by the first motor and the second motor is either positive or negative.

3. The torque distribution method for an electric vehicle according to claim 2, characterized in that, When the electric vehicle is in the forward state, the current vehicle speed and the required torque are substituted into the first torque distribution relationship to obtain the corresponding torque distribution coefficient, including: When the electric vehicle is in the forward state for a preset time, the current vehicle speed and the required torque are substituted into the first torque distribution relationship to obtain the corresponding torque distribution coefficient.

4. The torque distribution method for an electric vehicle according to claim 2, characterized in that, The step of allocating torque to the first motor and the second motor according to the torque allocation coefficient includes: According to the torque distribution coefficient, the first torque allocated to the first motor and the second torque allocated to the second motor are determined; The output torque of the first motor is controlled to gradually reach the first torque, and the output torque of the second motor is controlled to gradually reach the second torque.

5. The torque distribution method for an electric vehicle according to claim 4, characterized in that, The step of controlling the output torque of the first motor to gradually reach the first torque, and controlling the output torque of the second motor to gradually reach the second torque, includes: The output torque of the first motor is controlled to gradually increase or decrease by a preset torque value until the first torque is reached, and the output torque of the second motor is controlled to gradually increase or decrease by the preset torque value until the second torque is reached.

6. The torque distribution method for an electric vehicle according to claim 2, characterized in that, The first torque distribution relationship is determined through the following steps: Obtain the maximum speed of the electric vehicle; Based on the maximum vehicle speed and the external characteristic curves of the first motor and the second motor, the minimum allowable torque and the maximum allowable torque that the first motor and the second motor are allowed to output when the vehicle speed of the electric vehicle is less than the maximum vehicle speed are determined. The minimum allowable torque is the sum of the minimum allowable torques of the first motor and the second motor, and the maximum allowable torque is the sum of the maximum allowable torques of the first motor and the second motor. According to the first preset step size, the vehicle speed of the electric vehicle is grouped within the range of zero to the maximum vehicle speed, and the torque is grouped within the range of minimum allowable torque to maximum allowable torque; The grouped electric vehicles are arranged and combined according to their speed and torque. The torque distribution coefficients are grouped within a range of 0 to 1 according to a second preset step size. For each set of vehicle speed and torque, calculate the total efficiency of the first motor and the second motor corresponding to each set of torque distribution coefficient; The first torque distribution relationship exists between each group of vehicle speeds, torques, and the torque distribution coefficient corresponding to the highest overall efficiency.

7. The torque distribution method for an electric vehicle according to claim 1, characterized in that, When the electric vehicle is in the non-forward state, the method of allocating torque to the first motor and the second motor through a second torque distribution relationship includes: When the electric vehicle is in the non-forward state, the current vehicle speed and the required torque are substituted into the second torque distribution relationship to obtain the corresponding distributed torque; the distributed torque is the torque allocated to the first motor. According to the allocated torque, torque is allocated to the first motor and the second motor; The second torque distribution relationship is: the correspondence between the vehicle speed, torque and distributed torque of the electric vehicle when the total efficiency of the first motor and the second motor is at its highest; the distributed torque refers to the torque distributed by the first motor and the second motor, including positive torque and negative torque.

8. The torque distribution method for an electric vehicle according to claim 7, characterized in that, The second torque distribution relationship is determined through the following steps: Obtain the maximum speed of the electric vehicle; Based on the maximum vehicle speed and the external characteristic curves of the first motor and the second motor, determine the maximum allowable torque and the minimum allowable torque that the first motor and the second motor are allowed to output when the vehicle speed of the electric vehicle is less than the maximum vehicle speed. The maximum allowable torque is the sum of the maximum allowable torques of the first motor and the second motor, and the minimum allowable torque is the sum of the minimum allowable torques of the first motor and the second motor. According to the first preset step size, the vehicle speed of the electric vehicle is grouped within the range of zero to the maximum vehicle speed, and the torque is grouped within the range of minimum allowable torque to maximum allowable torque; The grouped electric vehicles are arranged and combined according to their speed and torque. Based on the maximum vehicle speed, determine the maximum and minimum torque that the first motor is allowed to output; According to the second preset step size, the allocated torque is grouped within the range from the minimum allowable output torque of the first motor to the maximum allowable output torque; For each set of vehicle speed and torque, calculate the total efficiency of the first motor and the second motor corresponding to each set of allocated torque; The second torque distribution relationship exists between each group of vehicle speeds, torques, and the allocated torque corresponding to the highest overall efficiency.

9. A torque distribution device for an electric vehicle, characterized in that, It includes one or more processors for implementing the torque distribution method for the electric vehicle according to any one of claims 1-8.

10. An electric vehicle, characterized in that, include: First motor; Second motor; and The torque distribution device as described in claim 9 is electrically connected to the first motor and the second motor.

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