Torque distribution method and apparatus for braking energy recovery of multi-electric-motor electric drive axle, and vehicle

Abstract

A torque distribution method and apparatus for braking energy recovery of a multi-electric-motor electric drive axle, and a vehicle. The method comprises the following steps: acquiring a required torque for braking energy of an electric drive axle and the rotational speed of an output end of the electric drive axle; on the basis of the acquired required torque for the braking energy of the electric drive axle and the acquired rotational speed of the output end of the electric drive axle and taking into account rotational speeds of electric motors, calculating braking energy recovery rates of the electric drive axle under different electric-motor braking torque distribution ratios; and on the basis of the calculated braking energy recovery rates of the electric drive axle under the different electric-motor braking torque distribution ratios, selecting the electric-motor braking torque distribution ratio that enables the maximum braking energy recovery rate of the electric drive axle, and using same as the braking torque distribution ratio of the electric drive axle under the current operating condition.

Description

Multi-motor electric drive axle braking energy recovery torque distribution method, device and vehicle Technical Field

[0001] The present invention relates to the field of mechanical transmission technology, and in particular to a method and device for distributing braking energy recovery torque of a multi-motor electric drive axle, and a vehicle. Background Art

[0002] Braking energy recovery is one of the advantageous functions of the electric drive system. It aims to reduce the heat lost during braking. During operation, it will cause the moving vehicle to generate corresponding resistance to achieve the braking effect, and the recovered mechanical energy will be recovered and stored in the form of chemical energy, hydraulic energy, etc. for the next use of the car, which helps to improve the vehicle's braking safety and power consumption economy.

[0003] Current research on brake energy regeneration systems focuses primarily on improving braking safety, comfort, and energy recovery rates. This research primarily focuses on single-motor drive systems for passenger vehicles, with limited research on brake energy regeneration in multi-motor drive systems. Multi-motor electric axles are a viable option for commercial vehicle electric drive systems. While the presence of multiple motors offers a wider range of operational possibilities for brake energy regeneration, it also presents challenges in torque distribution.

[0004] Therefore, how to distribute the braking energy torque of a multi-motor electric drive axle is a problem that needs to be solved at present. Summary of the Invention

[0005] In order to solve the problem of how to distribute braking energy torque when a multi-motor drive system recovers braking energy, the present invention provides a method, device and vehicle for distributing braking energy recovery torque of a multi-motor electric drive axle.

[0006] In a first aspect, the technical solution of the present invention provides a method for distributing braking energy recovery torque of a multi-motor electric drive axle, comprising the following steps:

[0007] Obtain the electric drive axle braking energy required torque and the electric drive axle output speed;

[0008] Based on the obtained electric drive axle braking energy demand torque and the electric drive axle output end speed combined with the motor speed, the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios is calculated;

[0009] According to the calculated braking energy recovery rates of the electric drive axle under different motor braking torque distribution ratios, the motor braking torque distribution ratio that maximizes the braking energy recovery rate of the electric drive axle is selected as the braking torque distribution ratio of the electric drive axle under the current working condition.

[0010] As a preferred embodiment of the technical solution of the present invention, after the step of obtaining the braking energy demand torque of the electric drive bridge and the speed of the output end of the electric drive bridge, the following steps are included:

[0011] Get the motor speed and the braking torque allocated to the motor;

[0012] Configure the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle based on the acquired information;

[0013] According to the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle, a calculation model for the braking energy recovery rate of the electric drive axle is constructed.

[0014] As a preferred embodiment of the technical solution of the present invention, the step of configuring the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle according to the acquired information includes:

[0015] Construct the motor's braking torque-speed-energy conversion efficiency characteristic function;

[0016] Calculating the motor braking energy conversion efficiency based on the braking torque allocated to the motor and the motor speed in combination with the motor's braking torque-speed-energy conversion efficiency characteristic function; or,

[0017] The motor braking energy conversion efficiency is found in a two-dimensional table based on the braking torque allocated to the motor and the motor speed.

[0018] As a preferred embodiment of the technical solution of the present invention, the braking torque-speed-energy conversion efficiency characteristic function of the motor is:

[0019]

[0020] in, Indicates the motor speed, Indicates the speed of the electric drive axle output end; Indicates the variable coefficient; the variable coefficient is selected according to the motor model.

[0021] As a preferred embodiment of the technical solution of the present invention, in the step of obtaining the rotational speed of the motor and the braking torque allocated to the motor, the step of obtaining the rotational speed of the motor includes:

[0022] Read the motor speed collected by the sensor; or,

[0023] Get the reduction ratio from the motor to the output end of the electric drive bridge;

[0024] The motor speed is calculated based on the reduction ratio from the motor to the output end of the electric drive axle and the speed of the output end of the electric drive axle.

[0025] As a preferred embodiment of the technical solution of the present invention, the electric drive axle braking energy recovery rate calculation model is:

[0026]

[0027] in, Indicates the electric drive axle braking energy recovery rate, represents the braking torque assigned to the motor, Indicates the motor braking energy conversion efficiency, Indicates the electric drive axle braking energy required torque.

[0028] As a preferred embodiment of the technical solution of the present invention, the step of calculating the braking energy recovery rate of the electric drive bridge under different motor braking torque distribution ratios based on the obtained electric drive bridge braking energy demand torque and the electric drive bridge output terminal speed combined with the output speed of the motor includes:

[0029] The braking energy demand torque of the electric drive axle, the braking torque of the distribution motor and the motor braking energy conversion efficiency are input into the electric drive axle braking energy recovery rate calculation model to calculate the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios.

[0030] The multi-motor electric drive axle brake energy distribution method provided in this application utilizes a constructed multi-motor electric drive axle brake energy recovery rate calculation model to calculate the brake energy recovery rate of the electric drive axle under different brake energy recovery torque distribution ratios and determine the distribution ratio that maximizes the brake energy recovery rate. This method achieves the distribution of brake energy recovery torque between the motors of the multi-motor electric drive axle. While ensuring the vehicle's braking needs, the vehicle's brake energy recovery rate is improved by coordinating and transferring brake torque between multiple motors, thereby contributing to the vehicle's endurance.

[0031] In a second aspect, the technical solution of the present invention provides a multi-motor electric drive axle braking energy recovery torque distribution device, comprising an acquisition module, a first calculation module and a distribution ratio acquisition module;

[0032] An acquisition module is used to obtain the braking energy demand torque of the electric drive axle and the speed of the output end of the electric drive axle;

[0033] The first calculation module is used to calculate the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios based on the obtained electric drive axle braking energy demand torque and the electric drive axle output terminal speed combined with the output speed of the motor;

[0034] The distribution ratio acquisition module is used to select the motor braking torque distribution ratio that maximizes the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios based on the calculated braking energy recovery rate of the electric drive axle. The motor braking torque distribution ratio is used as the braking torque distribution ratio of the electric drive axle under the current working condition.

[0035] As a preferred embodiment of the technical solution of the present invention, the device further includes a configuration module and a model creation module;

[0036] The acquisition module is also used to obtain the rotational speed of the motor and the braking torque allocated to the motor;

[0037] A configuration module, used to configure the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle based on the acquired information;

[0038] The model creation module is used to build an electric drive axle braking energy recovery rate calculation model based on the braking torque-speed-energy conversion efficiency characteristics of each motor in the electric drive axle.

[0039] As a preferred embodiment of the technical solution of the present invention, a configuration module is configured to construct a braking torque-speed-energy conversion efficiency characteristic function of the motor; the motor braking energy conversion efficiency is calculated based on the braking torque assigned to the motor and the speed of the motor combined with the braking torque-speed-energy conversion efficiency characteristic function of the motor; or,

[0040] The configuration module is used to search the motor braking energy conversion efficiency in a two-dimensional table according to the braking torque allocated to the motor and the speed of the motor.

[0041] As a preferred embodiment of the technical solution of the present invention, the braking torque-speed-energy conversion efficiency characteristic function of the motor is:

[0042]

[0043] in, Indicates the motor speed, Indicates the speed of the electric drive axle output end; Indicates the variable coefficient; the variable coefficient is selected according to the motor model.

[0044] As a preferred embodiment of the technical solution of the present invention, an acquisition module is used to read the speed of the motor collected by the sensor and obtain the reduction ratio from the motor to the output end of the electric drive bridge; or the device includes a second calculation module for calculating the motor speed based on the reduction ratio from the motor to the output end of the electric drive bridge and the speed of the output end of the electric drive bridge.

[0045] As a preferred embodiment of the technical solution of the present invention, the electric drive axle braking energy recovery rate calculation model is:

[0046]

[0047] in, Indicates the electric drive axle braking energy recovery rate, represents the braking torque assigned to the motor, Indicates the motor braking energy conversion efficiency, Indicates the electric drive axle braking energy required torque.

[0048] As a preferred embodiment of the technical solution of the present invention, the first calculation module is used to input the braking energy demand torque of the electric drive bridge, the braking torque allocated to the motor and the motor braking energy conversion efficiency into the electric drive bridge braking energy recovery rate calculation model, and calculate the braking energy recovery rate of the electric drive bridge under different motor braking torque distribution ratios.

[0049] In a third aspect, the technical solution of the present invention provides a vehicle, which distributes the braking energy recovery torque of the multi-motor electric drive axle through the method described in the first aspect.

[0050] As can be seen from the above technical solution, the present invention has the following advantages: Using a multi-motor electric drive axle brake energy recovery rate calculation model, the present invention calculates the brake energy recovery rate of the electric drive axle under different brake energy recovery torque distribution ratios and determines the distribution ratio that maximizes the brake energy recovery rate. This achieves the distribution of brake energy recovery torque between the motors of the multi-motor electric drive axle, improving the vehicle's brake energy recovery rate while ensuring the vehicle's braking requirements, thereby contributing to improved vehicle endurance.

[0051] In addition, the present invention has a reliable design principle, a simple structure and a very broad application prospect.

[0052] It can be seen that compared with the prior art, the present invention has outstanding substantial features and significant progress, and the beneficial effects of its implementation are also obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0054] FIG1 is a schematic flow chart of a method according to an embodiment of the present invention.

[0055] FIG2 is a schematic flow chart of a method according to another embodiment of the present invention.

[0056] FIG3 is a schematic block diagram of an apparatus according to an embodiment of the present invention.

[0057] FIG4 is a schematic diagram of a multi-motor drive bridge provided in an embodiment of the present application. DETAILED DESCRIPTION

[0058] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0059] As shown in FIG1 , an embodiment of the present invention provides a method for distributing braking energy recovery torque of a multi-motor electric drive axle, comprising the following steps:

[0060] Step 1: Obtain the braking energy required torque of the electric drive axle and the speed of the electric drive axle output end;

[0061] Step 2: Based on the obtained electric drive axle braking energy demand torque and the electric drive axle output end speed combined with the motor speed, calculate the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios;

[0062] Step 3: Based on the calculated braking energy recovery rates of the electric drive axle under different motor braking torque distribution ratios, select the motor braking torque distribution ratio that maximizes the braking energy recovery rate of the electric drive axle as the braking torque distribution ratio of the electric drive axle under the current working condition.

[0063] The multi-motor electric axle's brake energy recovery rate calculation model calculates the brake energy recovery rate of the electric axle under different brake energy recovery torque distribution ratios and determines the distribution ratio that maximizes the brake energy recovery rate. This achieves the distribution of brake energy recovery torque between the motors of the multi-motor electric axle, improving the vehicle's brake energy recovery rate while ensuring the vehicle's braking needs, thereby enhancing the vehicle's range.

[0064] An embodiment of the present invention provides a method for distributing braking energy recovery torque in a multi-motor electric drive bridge, as shown in FIG4 . The electric drive bridge includes at least two motors connected to the output end of the electric drive bridge via a reduction mechanism, as shown in FIG2 . The method includes:

[0065] S100: Configuring the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle and the reduction ratio information from each motor to the output end of the electric drive axle.

[0066] Generally, the external characteristics of each motor are obtained by bench testing or simulation of the energy conversion efficiency when the motor is working under different braking torques and speeds. Specifically, the braking torque-speed-energy conversion efficiency characteristic function of the motor obtained by the test is:

[0067]

[0068] in, Indicates the motor speed, Indicates the speed of the electric drive axle output end; represents the coefficient of the variable.

[0069] In the specific implementation process, a mapping relationship between variable coefficients and motor models is preset, and the corresponding variable coefficients are selected according to the motor model used.

[0070] Specifically, a feasible mapping relationship between variable coefficients and motor models is shown in Table 1:

[0071] Table 1

[0072]

[0073] Substitute the above variable coefficients into the motor braking torque-speed-energy conversion efficiency characteristic function, and then in the subsequent steps, substitute the obtained motor speed and motor torque into the function to calculate the energy conversion efficiency.

[0074] In some embodiments, the braking torque-speed-energy conversion efficiency characteristics of the motor can also be represented by a two-dimensional lookup table. Specifically, a feasible two-dimensional lookup table is shown in Table 2:

[0075] Table 2

[0076]

[0077] In a specific implementation process, the braking energy conversion efficiency value of the motor can be found through the above table according to the braking torque allocated to the motor and the speed of the motor.

[0078] It should be noted that the motor speed can be directly obtained by reading the motor speed information collected in real time by the motor itself, or it can be calculated based on the reduction ratio information from the motor to the electric drive axle output end and the wheel speed information at the electric drive axle output end.

[0079] S200: Constructing a calculation model for the braking energy recovery rate of the electric drive axle based on the braking torque-speed-energy conversion efficiency characteristics of each motor.

[0080] Specifically, the electric drive axle braking energy recovery rate calculation model is expressed by the following formula:

[0081]

[0082] in, Indicates the electric drive axle braking energy recovery rate, represents the braking torque assigned to the motor, Indicates the motor braking energy conversion efficiency, Indicates the electric drive axle braking energy required torque.

[0083] It should be noted here that due to the limitation of motor energy conversion efficiency, not all of the motor's braking energy will be converted into electrical energy and transmitted to the battery system. Specifically, part of the motor's braking energy will be converted into electrical energy and transmitted to the battery system, and part will be lost in the form of heat due to motor iron loss, copper loss, etc. The conversion efficiency of this process is calculated using express.

[0084] S300: Obtaining the electric drive axle braking energy required torque and the electric drive axle output end speed.

[0085] In practice, the electric drive axle's braking energy demand torque is typically determined by detecting brake pedal travel. It can also be determined through predictive driving to obtain future road condition information. The specific acquisition process is not detailed in this embodiment. The electric drive axle's output speed is obtained using a speed sensor located at the output end.

[0086] S400: Based on the established electric drive bridge braking energy recovery rate calculation model, the obtained electric drive bridge braking energy demand torque and the electric drive bridge output terminal speed, and the configured reduction ratio information of each motor to the output terminal, the braking energy recovery rate of the electric drive bridge under different motor braking torque distribution ratios is calculated.

[0087] In the specific implementation process, the braking torque distribution ratio between each motor changes according to the set step size (such as 10%), and the braking energy demand torque of the electric drive axle is distributed to each motor. For example, if the braking energy demand torque of a dual-motor electric drive axle is 5000Nm, the braking torque data distributed to the two motors are shown in Table 3:

[0088] Table 3

[0089]

[0090] The obtained electric drive axle output speed is 200 rpm.

[0091] Specifically, the following illustrates the implementation process of the braking energy recovery rate in this step with a distribution ratio of 90:10.

[0092] The reduction ratio from motor A to the output end configured in S200 is 15, and the reduction ratio from motor B to the output end is 20. The calculated rotation speed of motor A is 3000 rpm, and the rotation speed of motor B is 4000 rpm.

[0093] The braking torque of motor A is 4500 / 15=300Nm, and the braking torque of motor B is 500 / 20=25Nm. Based on the braking torque-speed-energy conversion efficiency characteristics of the motors configured in S100, it can be calculated or looked up in a table that the energy conversion efficiency of motor A is approximately 95%, and the energy conversion efficiency of motor B is approximately 91%.

[0094] The braking energy recovery rate of the electric drive axle under the motor braking torque distribution ratio is calculated based on the electric drive axle braking energy recovery rate calculation model constructed in S300 as follows:

[0095]

[0096] During the specific implementation process, the braking energy recovery rates under all possible motor braking torque distribution ratios are calculated.

[0097] S500: Based on the calculated braking energy recovery rates of the electric drive axle under different motor braking torque distribution ratios, selecting the motor braking torque distribution ratio that maximizes the braking energy recovery rate of the electric drive axle as the braking torque distribution ratio of the electric drive axle under the current working condition.

[0098] In the specific implementation process, according to the braking energy recovery rates under all possible motor braking torque distribution ratios calculated in step S400, the distribution ratio that maximizes the braking energy recovery rate is selected as the braking torque distribution ratio of the electric drive axle under the current working condition.

[0099] S600: Sending kinetic energy recovery torque distribution information of each motor mechanism of the electric drive axle.

[0100] The braking torque distribution ratio of the electric drive axle under the current working condition obtained by the above selection is sent to the control system for motor torque distribution control.

[0101] As shown in FIG3 , an embodiment of the present invention provides a multi-motor electric drive axle braking energy recovery torque distribution device, including an acquisition module, a configuration module, a first calculation module, a model creation module, a first calculation module, and a distribution ratio acquisition module;

[0102] The acquisition module is also used to obtain the motor speed and the braking torque allocated to the motor; and obtain the braking energy demand torque of the electric drive bridge and the speed of the output end of the electric drive bridge;

[0103] A configuration module is used to configure the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle and the reduction ratio of each motor to the output end of the electric drive axle according to the acquired information;

[0104] The model creation module is used to build an electric drive axle braking energy recovery rate calculation model based on the braking torque-speed-energy conversion efficiency characteristics of each motor in the electric drive axle.

[0105] A second calculation module is used to calculate the rotation speed of each motor based on the reduction ratio from each motor to the output end of the electric drive bridge and the rotation speed of the output end of the electric drive bridge;

[0106] The first calculation module is used to calculate the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios based on the obtained electric drive axle braking energy demand torque and the electric drive axle output terminal speed combined with the output speed of the motor;

[0107] The distribution ratio acquisition module is used to select the motor braking torque distribution ratio that maximizes the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios based on the calculated braking energy recovery rate of the electric drive axle. The motor braking torque distribution ratio is used as the braking torque distribution ratio of the electric drive axle under the current working condition.

[0108] The second calculation module calculates the speed of motor A and the speed of motor B based on the reduction ratio of motor A to the output end and the reduction ratio of motor B to the output end configured in the configuration module. Enter the first calculation module to calculate: the braking torque of motor A and the braking torque of motor B. Further, based on the braking torque-speed-energy conversion efficiency characteristics of the motors configured in the configuration module, the energy conversion efficiency of motor A and the energy conversion efficiency of motor B can be calculated or looked up in a table. The braking energy recovery rate of the electric drive axle under the motor braking torque distribution ratio is calculated based on the electric drive axle braking energy recovery rate calculation model constructed in the model construction module. In the specific implementation process, the braking energy recovery rate under all possible motor braking torque distribution ratios is calculated.

[0109] According to the braking energy recovery rates of the electric drive axle under different motor braking torque distribution ratios calculated by the first calculation module, the motor braking torque distribution ratio that maximizes the braking energy recovery rate of the electric drive axle is selected as the braking torque distribution ratio of the electric drive axle under the current working condition.

[0110] During the specific implementation process, based on the braking energy recovery rates under all possible motor braking torque distribution ratios calculated by the first calculation module, the distribution ratio that maximizes the braking energy recovery rate is selected as the braking torque distribution ratio of the electric drive axle under the current working condition.

[0111] It should be noted that the device also includes a distribution information output module for sending the selected braking torque distribution ratio of the electric drive axle under the current working condition to the vehicle control system for motor torque distribution control.

[0112] An embodiment of the present invention provides a vehicle, which includes the multi-motor electric drive axle braking energy recovery torque distribution device described in the above embodiment; or the vehicle performs multi-motor electric drive axle braking energy recovery torque distribution through the method described in the above embodiment.

[0113] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0114] The disclosed embodiment of the present invention provides an embodiment of a multi-motor electric drive axle braking energy recovery torque distribution device. This device and the multi-motor electric drive axle braking energy recovery torque distribution method of the above-mentioned embodiments belong to the same inventive concept. For details not fully described in the embodiment of the multi-motor electric drive axle braking energy recovery torque distribution device, refer to the embodiment of the above-mentioned multi-motor electric drive axle braking energy recovery torque distribution method.

[0115] The multi-motor electric drive axle braking energy recovery torque distribution method is a unit and algorithm step of each example described in combination with the embodiments disclosed in this article. It can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0116] Those skilled in the art will appreciate that various aspects of the multi-motor electric drive axle braking energy recovery torque distribution method can be implemented as a system, method, or program product. Therefore, various aspects of the present disclosure can be specifically implemented in the following forms: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation that combines hardware and software aspects, which may be collectively referred to herein as a "circuit," "module," or "system."

[0117] Although the present invention has been described in detail with reference to the accompanying drawings and in conjunction with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any person skilled in the art who can easily conceive of changes or substitutions within the technical scope disclosed in the present invention shall be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope of protection of the claims.

Claims

1. A method for distributing braking energy recovery torque of a multi-motor electric drive bridge, characterized in that: The steps include: Obtain the electric drive axle braking energy demand torque and the electric drive axle output end speed; According to the acquired electric drive axle braking energy demand torque and the electric drive axle output end speed combined with the motor speed, the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios is calculated; According to the calculated braking energy recovery rates of the electric drive axle under different motor braking torque distribution ratios, the motor braking torque distribution ratio that maximizes the braking energy recovery rate of the electric drive axle is selected as the braking torque distribution ratio of the electric drive axle under the current working condition; The steps of obtaining the electric drive axle braking energy demand torque and the electric drive axle output end speed include: Obtain the motor speed and the braking torque allocated to the motor; Configure the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle according to the acquired information; According to the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle, a calculation model for the braking energy recovery rate of the electric drive axle is constructed; The steps of configuring the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle according to the acquired information include: Construct the motor's braking torque-speed-energy conversion efficiency characteristic function; Calculating the motor braking energy conversion efficiency according to the braking torque allocated to the motor and the speed of the motor combined with the motor braking torque-speed-energy conversion efficiency characteristic function; The motor's braking torque-speed-energy conversion efficiency characteristic function: ,in, Indicates the motor speed, Indicates the variable coefficient preset according to the motor model. ； Electric drive axle braking energy recovery rate calculation model: ,in, Indicates the electric drive axle braking energy recovery rate, represents the braking torque assigned to the motor, Indicates the motor braking energy conversion efficiency, Indicates the electric drive axle braking energy demand torque.

2. The multi-motor electric drive axle braking energy recovery torque distribution method according to claim 1 is characterized in that: The steps of configuring the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle according to the acquired information include: The motor braking energy conversion efficiency is found in a two-dimensional table based on the braking torque allocated to the motor and the motor speed.

3. The multi-motor electric drive axle braking energy recovery torque distribution method according to claim 1 or 2, characterized in that: The steps of calculating the braking energy recovery rate of the electric drive bridge under different motor braking torque distribution ratios according to the obtained electric drive bridge braking energy demand torque and the electric drive bridge output end speed combined with the output speed of the motor include: The braking energy demand torque of the electric drive axle, the braking torque allocated to the motor and the motor braking energy conversion efficiency are input into the electric drive axle braking energy recovery rate calculation model to calculate the braking energy recovery rate of the electric drive axle under different motor braking torque allocation ratios.

4. A multi-motor electric drive axle braking energy recovery torque distribution device, characterized in that: The device adopts the multi-motor electric drive axle braking energy recovery torque distribution method as claimed in any one of claims 1 to 3, including an acquisition module, a first calculation module and a distribution ratio acquisition module; An acquisition module is used to acquire the braking energy demand torque of the electric drive axle and the output speed of the electric drive axle; The first calculation module is used to calculate the braking energy recovery rate of the electric drive bridge under different motor braking torque distribution ratios according to the acquired electric drive bridge braking energy demand torque and the electric drive bridge output terminal speed combined with the output speed of the motor; The distribution ratio acquisition module is used to select the motor braking torque distribution ratio that maximizes the braking energy recovery rate of the electric drive axle according to the calculated braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios, as the braking torque distribution ratio of the electric drive axle under the current working condition.

5. The multi-motor electric drive axle braking energy recovery torque distribution device according to claim 4 is characterized in that: The device also includes a configuration module and a model creation module; The acquisition module is also used to acquire the rotation speed of the motor and the braking torque allocated to the motor; A configuration module, used to configure the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle according to the acquired information; The model creation module is used to construct a calculation model for the braking energy recovery rate of the electric drive axle based on the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle.

6. A vehicle, characterized in that: The vehicle distributes multi-motor electric drive axle braking energy recovery torque through the method described in any one of claims 1-3.

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