CN117584755B - Multi-motor electric drive axle braking energy recovery torque distribution method and device and vehicle - Google Patents

Abstract

The invention belongs to the technical field of mechanical transmission, and particularly provides a multi-motor drive bridge braking energy recovery torque distribution method, a device and a vehicle, wherein the method comprises the following steps: acquiring the braking energy demand torque of the electric drive bridge and the rotating speed of an output end of the electric drive bridge; according to the acquired electric drive bridge braking energy demand torque and the electric drive bridge output end rotating speed combined with the rotating speed of the motor, calculating the braking energy recovery rate of the electric drive bridge under different motor braking torque distribution ratios; and selecting the motor braking torque distribution ratio which enables the braking energy recovery rate of the electric drive bridge to be maximum as the braking torque distribution ratio of the electric drive bridge under the current working condition according to the calculated braking energy recovery rates of the electric drive bridge under different motor braking torque distribution ratios. Under the condition of guaranteeing the braking requirement of the vehicle, the braking torque coordination and transfer among the plurality of motors are used for improving the braking energy recovery rate of the vehicle, and the cruising ability of the vehicle is improved.

Description

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

Technical Field

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

Background Art

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. The recovered mechanical energy will be stored in the form of chemical energy, hydraulic energy, etc. for the next use of the vehicle, which helps to improve the vehicle's braking safety and power consumption economy.

At present, the research on the brake energy recovery system is mainly aimed at improving its braking safety, comfort and energy recovery rate. The research object is mainly the single-motor drive system of passenger cars, and there is less research on the brake energy recovery of multi-motor drive systems. Multi-motor electric drive axles are one of the feasible routes for commercial vehicle electric drive systems. The existence of multiple motors provides more operational possibilities for the brake energy recovery of electric drive axles, but also brings challenges to its brake energy recovery torque distribution.

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

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.

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 bridge, comprising the following steps:

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.

As a preferred embodiment of the technical solution of the present invention, 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 includes:

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.

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:

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

Calculate the motor braking energy conversion efficiency based on the braking torque allocated to the motor and the motor speed combined with the motor braking torque-speed-energy conversion efficiency characteristic function; or,

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.

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:

η _M ＝p ₀₀ +p ₁₀ *n _M +p ₀₁ *T _M +p ₂₀ *n _M ² +p ₁₁ *n _M *T _M +p ₀₂ *T _M ² +p ₂₁ *n _M ² *T _M +p ₁₂ *n _M *T _M ² p ₀₃ *T _M ³ +p ₂₂ *n _M ² *T _M ² +p ₁₃ *n _M *T _M ² +p ₀₄ *T _M ⁴ +p ₂₃ *n _M ² *T _M ³ +p ₁₄ *n _M *T _M ⁴ +p ₀₅ *T _M ⁵

Among them, n _M represents the speed of the motor, n _W represents the speed of the output end of the electric drive bridge; p _{j, k} (j=1, 2; k=1, 2, 3, 4, 5) represents the variable coefficient; the variable coefficient is selected according to the motor model.

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:

Read the motor speed collected by the sensor; or,

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

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.

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

Among them, η _Axle represents the braking energy recovery rate of the electric drive axle, T _Mi represents the braking torque allocated to the motor, η _Mi represents the motor braking energy conversion efficiency, and T _W represents the braking energy demand torque of the electric drive axle.

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 according to 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:

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.

The multi-motor electric drive axle braking energy distribution method provided in the present application uses the constructed multi-motor electric drive axle braking energy recovery rate calculation model to calculate the braking energy recovery rate of the electric drive axle under different braking energy recovery torque distribution ratios, and gives the distribution ratio that makes the braking energy recovery rate the highest, thereby realizing the distribution of braking energy recovery torque between each motor of the multi-motor electric drive axle. While ensuring the braking needs of the vehicle, the braking energy recovery rate of the vehicle is improved by coordinating and transferring the braking torque between multiple motors, which helps to improve the vehicle's endurance.

In a second aspect, the technical solution of the present invention provides a multi-motor electric drive axle braking energy recovery torque distribution device, 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.

As a preferred embodiment of the technical solution of the present invention, the device further 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 according to the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle.

As a preferred embodiment of the technical solution of the present invention, a configuration module is used to construct a braking torque-speed-energy conversion efficiency characteristic function of the motor; the motor braking energy conversion efficiency is calculated according to 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,

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 rotation speed of the motor.

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: ηM＝p ₀₀ +p ₁₀ *n _M +p ₀₁ *T _M +p ₂₀ *n _M ² +p ₁₁ *n _M *T _M +p ₀₂ *T _M ² +p ₂₁ *n _M ² *T _M +p ₁₂ *n _M *T _M ² +p ₀₃ *T _M ³ +p ₂₂ *n _M ² *T _M ² +p ₁₃ *n _M *T _M ² +p ₀₄ *T _M ⁴ +p ₂₃ *n _M ² *T _M ³ +p ₁₄ *n _M *T _M ⁴ +p ₀₅ *T _M ⁵

Among them, n _M represents the speed of the motor, n _W represents the speed of the output end of the electric drive bridge; p _{j, k} (j=1, 2; k=1, 2, 3, 4, 5) represents the variable coefficient; the variable coefficient is selected according to the motor model.

As a preferred embodiment of the technical solution of the present invention, an acquisition module is used to read the rotational 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, which is used to calculate the motor rotational speed based on the reduction ratio from the motor to the output end of the electric drive bridge and the rotational speed of the output end of the electric drive bridge.

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

Among them, η _Axle represents the braking energy recovery rate of the electric drive axle, T _Mi represents the braking torque allocated to the motor, η _Mi represents the motor braking energy conversion efficiency, and T _W represents the braking energy demand torque of the electric drive axle.

As a preferred embodiment of the technical solution of the present invention, the first calculation module is used to input the electric drive bridge braking energy demand torque, 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.

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

It can be seen from the above technical solutions that the present invention has the following advantages: the present invention calculates the braking energy recovery rate of the electric drive bridge under different braking energy recovery torque distribution ratios through a multi-motor electric drive bridge braking energy recovery rate calculation model, and gives a distribution ratio that makes the braking energy recovery rate the highest. The distribution of braking energy recovery torque between each motor of the multi-motor electric drive bridge is realized, and the braking energy recovery rate of the vehicle is improved while ensuring the braking demand of the vehicle, which helps to improve the endurance of the vehicle.

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

It can be seen that compared with the prior art, the present invention has outstanding substantive features and significant progress, and the beneficial effects of its implementation are also obvious.

BRIEF DESCRIPTION OF THE DRAWINGS

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

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

FIG. 2 is a schematic flow chart of a method according to another embodiment of the present invention.

FIG. 3 is a schematic block diagram of an apparatus according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a multi-motor drive bridge provided in an embodiment of the present application.

DETAILED DESCRIPTION

In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work should fall within the scope of protection of the present invention.

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

Step 1: Obtain the electric drive axle braking energy demand torque and the electric drive axle output end speed;

Step 2: Calculate the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios based on the acquired electric drive axle braking energy demand torque and the electric drive axle output terminal speed combined with the motor speed;

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.

The braking energy recovery rate calculation model of the multi-motor electric drive axle is used to calculate the braking energy recovery rate of the electric drive axle under different braking energy recovery torque distribution ratios, and the distribution ratio that makes the braking energy recovery rate the highest is given. The braking energy recovery torque distribution between the motors of the multi-motor electric drive axle is realized, and the braking energy recovery rate of the vehicle is improved while ensuring the braking needs of the vehicle, which helps to improve the vehicle's endurance.

An embodiment of the present invention provides a method for distributing braking energy recovery torque of a multi-motor electric drive bridge, as shown in FIG4 , wherein the electric drive bridge includes at least two motors, which are connected to the output end of the electric drive bridge through a reduction mechanism, as shown in FIG2 , and the method includes:

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

Generally, the external characteristics are obtained by bench testing or simulating the energy conversion efficiency of each motor when it works at different braking torques and speeds. Specifically, the braking torque-speed-energy conversion efficiency characteristic function of the motor obtained by the test is:

η _M ＝p ₀₀ +p ₁₀ *n _M +p ₀₁ *T _M +p ₂₀ *n _M ² +p ₁₁ *n _M *T _M +p ₀₂ *T _M ² +p ₂₁ *n _M ² *T _M +p ₁₂ *n _M *T _M ² +p ₀₃ *T _M ³ +p ₂₂ *n _M ² 2*T _M ² +p ₁₃ *n _M *T _M ² +p ₀₄ *T _M ⁴ +p ₂₃ * n _M ² *T _M ³ +p ₁₄ *n _M *T _M ⁴ +p ₀₅ *T _M ⁵

Wherein, n _M = represents the rotation speed of the motor, n _W represents the rotation speed of the output end of the electric drive bridge; p _{j, k} (j = 1, 2; k = 1, 2, 3, 4, 5) represents the variable coefficient.

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.

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

Table 1

p00 p10 p01 p20 p11 p02 p21 p12 50kW motor 1 0.8765 -3.809e-06 0.003645 -1.869e-10 4.49e-07 -7.501e-05 -1.589e-11 -4.232e-09 70kW motor 2 0.9236 -3.945e-05 0.00262 2.89e-09 1.093e-06 -5.96e-05 -7.604e-11 -8.763e-09 p03 p22 p13 p04 p23 p14 p05 - 50kW motor 1 6.086e-07 1.352e-13 2.199e-11 -2.255e-09 -7.865e-16 -2.92e-14 3.046e-12 - 70kW motor 2 4.987e-07 5.428e-13 3.165e-11 -1.837e-09 -1.537e-15 -3.317e-14 2.437e-12 -

Substitute the above variable coefficients into the motor braking torque-speed-energy conversion efficiency characteristic function, and then in the subsequent steps, the energy conversion efficiency can be calculated based on the obtained motor speed and motor torque.

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:

Table 2

Torque 12 89.81% 93.76% 95.05% 95.82% 96.18% Torque 11 90.42% 94.06% 95.23% 95.96% 96.32% 95.97% Torque 10 90.98% 94.33% 95.38% 96.05% 96.35% 96.26% 95.42% Torque 9 91.48% 94.54% 95.49% 96.11% 96.42% 96.36% 95.90% Torque 8 91.98% 94.75% 95.64% 96.18% 96.42% 96.45% 96.12% 95.45% 94.24% Torque 7 92.47% 94.92% 95.70% 96.17% 96.40% 96.43% 96.24% 95.79% 95.18% Torque 6 92.90% 95.06% 95.75% 96.18% 96.31% 96.39% 96.26% 95.98% 95.53% 94.98% 94.56% Torque 5 93.35% 95.18% 95.73% 96.08% 96.12% 96.16% 96.18% 95.85% 95.59% 95.35% 95.17% 94.95% Torque 4 93.70% 95.22% 95.62% 95.86% 95.82% 95.74% 95.84% 95.72% 95.47% 95.39% 95.44% 95.57% Torque 3 94.20% 95.13% 95.35% 95.53% 95.26% 95.12% 95.16% 95.09% 94.91% 95.00% 95.26% 95.80% Torque 2 94.28% 94.75% 94.69% 94.60% 93.88% 93.91% 93.34% 93.80% 93.76% 94.16% 94.75% 95.58% Torque 1 93.49% 92.84% 92.02% 91.68% 90.98% 89.80% 89.50% 89.93% 90.24% 91.25% 92.40% 93.87% Speed 1 Speed 2 Speed 3 Speed 4 Speed 5 Speed 6 Speed 7 Speed 8 Speed 9 Speed 10 Speed 11 Speed 12

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.

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.

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.

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

Among them, η _Axle represents the electric drive axle braking energy recovery rate, T _Mi and η _Mi represent the braking torque allocated to the motor and the motor braking energy conversion efficiency respectively, and T _W represents the electric drive axle braking energy demand torque.

It should be noted here that due to the limitation of motor energy conversion efficiency, the motor's braking recovery energy will not be fully 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 energy due to motor iron loss, copper loss, etc. The conversion efficiency of this process is represented by η _M.

S300: Obtaining the electric drive axle braking energy demand torque and the electric drive axle output end speed.

In the specific implementation process, the electric drive axle braking energy demand torque is generally obtained by detecting the travel of the brake pedal, and can also be obtained through future road condition information obtained by predictive driving. The specific acquisition process will not be explained in detail in this embodiment. The speed of the output end of the electric drive axle is obtained by a speed sensor arranged at the output end.

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

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 bridge is distributed to each motor. For example, the braking energy demand torque of a dual-motor electric drive bridge is 5000Nm, and the braking torque data distributed to the two motors are shown in Table 3:

Table 3

Allocation ratio 100:0 90:10 … 10:90 0:100 Braking torque assigned to motor 1/Nm 5000 4500 … 500 0 Braking torque allocated to motor 2/Nm 0 500 … 4500 5000

The obtained electric drive axle output speed is 200rpm.

Specifically, the implementation process of the braking energy recovery rate in this step is explained below with a distribution ratio of 90:10.

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 speed of motor A is calculated to be 3000 rpm, and the speed of motor B is calculated to be 4000 rpm.

The braking torque of motor A is 4500/15=300Nm, and the braking torque of motor B is 500/20=25Nm. According to 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 about 95%, and the energy conversion efficiency of motor B is about 91%. According to the electric drive axle braking energy recovery rate calculation model constructed in S300, the braking energy recovery rate of the electric drive axle under the motor braking torque distribution ratio is calculated as:

In the specific implementation process, the braking energy recovery rates under all possible motor braking torque distribution ratios are calculated.

S500: 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.

During 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.

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

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.

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;

The acquisition module is also used to acquire the rotation speed of the motor and the braking torque allocated to the motor; and to acquire the braking energy demand torque of the electric drive axle and the rotation speed of the output end of the electric drive axle;

A configuration module, 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;

The model creation module is used to construct a calculation model for the braking energy recovery rate of the electric drive axle according to the braking torque-speed-energy conversion efficiency characteristics of each motor of the electric drive axle.

A second calculation module is used to calculate the rotation speed of each motor according to 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;

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.

The second calculation module calculates the speed of motor A and the speed of motor B according to 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, according to the braking torque-speed-energy conversion efficiency characteristics of the motor 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 the table. The braking energy recovery rate of the electric drive axle under the motor braking torque distribution ratio is calculated according to 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.

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.

During the specific implementation process, according to 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.

It should be noted that the device also includes a distribution information output module, which is used to send the selected braking torque distribution ratio of the electric drive axle under the current working condition to the control system of the vehicle for motor torque distribution control.

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.

It should be understood that the order of execution of the steps in the above embodiment does not necessarily 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 embodiment of the present invention.

An embodiment of a multi-motor electric drive axle braking energy recovery torque distribution device is provided in an embodiment disclosed in the present invention. The device and the multi-motor electric drive axle braking energy recovery torque distribution method in the above-mentioned embodiments belong to the same inventive concept. For details not described in detail in the embodiment of the multi-motor electric drive axle braking energy recovery torque distribution device, reference can be made to the embodiment of the above-mentioned multi-motor electric drive axle braking energy recovery torque distribution method.

The multi-motor electric drive axle braking energy recovery torque distribution method is a combination of the units and algorithm steps of each example described in the embodiments disclosed herein, which 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.

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, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software, which can be collectively referred to as "circuit", "module" or "system" here.

Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the 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 these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims (6)

1. A method for distributing torque of braking energy recovery of a multi-motor electric drive bridge, characterized in that it comprises the following steps: 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 in combination 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 method for distributing braking energy recovery torque of a multi-motor electric drive axle according to claim 1 is characterized in that 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 comprises: 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 is characterized in that the step of calculating the braking energy recovery rate of the electric drive axle under different motor braking torque distribution ratios according to 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 comprises: 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 according to 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, 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 an electric drive axle braking energy recovery rate calculation model 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 the braking energy recovery torque of a multi-motor electric drive axle by the method described in any one of claims 1 to 3.