CN112009271A

CN112009271A - Power distribution method and device for four-wheel drive electric vehicle

Info

Publication number: CN112009271A
Application number: CN202010837437.6A
Authority: CN
Inventors: 范良明
Original assignee: Evergrande New Energy Automobile Investment Holding Group Co Ltd
Current assignee: Evergrande New Energy Automobile Investment Holding Group Co Ltd
Priority date: 2020-08-19
Filing date: 2020-08-19
Publication date: 2020-12-01
Also published as: WO2022037651A1

Abstract

The embodiment of the specification provides a power distribution method and device for a four-wheel drive electric vehicle, wherein at least two motors are mounted on the four-wheel drive electric vehicle. The method comprises the following steps: acquiring the required torque of a driver for operating the vehicle and the real-time rotating speed of the motor during the running of the vehicle; obtaining the loss power of the corresponding motor when different torques are generated under the real-time rotating speed from the loss power meter corresponding to each motor; according to the torque sum value as the required torque, randomly selecting one torque from the acquired torques corresponding to each motor to be combined, and calculating the loss power sum value corresponding to each torque combination; and determining the torque distribution proportion of the required torque in the at least two motors according to the loss power sum value corresponding to each torque combination, so that the loss power sum value corresponding to the determined torque distribution proportion meets the preset requirement, and the problem of low motor system efficiency of the four-wheel drive electric vehicle caused by the conventional torque distribution mode is solved.

Description

Power distribution method and device for four-wheel drive electric vehicle

Technical Field

The document relates to the technical field of vehicles, in particular to a power distribution method and device for a four-wheel-drive electric vehicle.

Background

At present, the power distribution mode of a four-wheel drive electric automobile is as follows: after the torque required by a driver is analyzed by a Vehicle Control Unit (VCU), the torque is simply distributed to the motors on the vehicle in equal proportion or other empirical proportion, and two motors, namely a front motor and a rear motor, are installed on a conventional four-wheel drive electric vehicle. The front and rear motors adjust output torque according to the VCU commands. The torque distribution mode can cause the efficiency of a motor system to be low, so that the energy consumption and the endurance of the whole vehicle are adversely affected.

Disclosure of Invention

The specification provides a power distribution method and a power distribution device for a four-wheel drive electric vehicle, which are used for solving the problem of low motor system efficiency of the four-wheel drive electric vehicle caused by the existing torque distribution mode.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

in a first aspect, the embodiments of the present specification provide a power distribution method for a four-wheel drive electric vehicle, where at least two electric motors are installed on the four-wheel drive electric vehicle. The method comprises the following steps:

acquiring the required torque of a driver for operating the vehicle and the real-time rotating speed of the motor during the running of the vehicle;

obtaining the loss power of the corresponding motor when different torques are generated under the real-time rotating speed from the loss power meter corresponding to each motor;

according to the torque sum value as the required torque, randomly selecting one torque from the acquired torques corresponding to each motor to be combined, and calculating the loss power sum value corresponding to each torque combination;

and determining the torque distribution proportion of the required torque in the at least two electric machines according to the loss power sum value corresponding to each torque combination, so that the loss power sum value corresponding to the determined torque distribution proportion meets the preset requirement.

In a second aspect, the embodiments of the present specification provide a power distribution device for a four-wheel drive electric vehicle, on which at least two electric motors are mounted. The device includes:

the data acquisition module is used for acquiring the required torque of a driver for operating the vehicle and the real-time rotating speed of the motor during the running period of the vehicle;

the torque acquisition module is used for acquiring the loss power of the corresponding motor when different torques are generated at the real-time rotating speed from the loss power meter corresponding to each motor;

the combined calculation module is used for selecting one torque from the acquired torques corresponding to each motor to be combined according to the torque sum value serving as the required torque, and calculating the loss power sum value corresponding to each torque combination;

and the torque distribution module determines the torque distribution proportion of the required torque in the at least two motors according to the loss power sum value corresponding to each torque combination, so that the loss power sum value corresponding to the determined torque distribution proportion meets a preset requirement.

The four-wheel drive electric vehicle is provided with at least two motors, and the required torque of a driver for operating the vehicle and the real-time rotating speed of the motors are acquired during the running of the vehicle; obtaining the loss power of the corresponding motor when different torques are generated at the real-time rotating speed from the loss power meter corresponding to each motor; according to the torque sum value as the required torque, randomly selecting one torque from the acquired torques corresponding to each motor to combine, and calculating the loss power sum value corresponding to each torque combination; according to the loss power and the value corresponding to each torque combination, the torque distribution proportion of the required torque in at least two motors is determined, so that the loss power and the value corresponding to the determined torque distribution proportion meet the preset requirement, the power of the whole vehicle is reasonably distributed, the motor system efficiency of the four-wheel-drive electric vehicle is improved, and the adverse effects on energy consumption and endurance are reduced.

Drawings

In order to more clearly illustrate one or more embodiments or prior art solutions of the present specification, the drawings that are needed in the description of the embodiments or prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present specification, and that other drawings can be obtained by those skilled in the art without inventive exercise.

Fig. 1 is a schematic view of an application scenario of a power distribution method of a four-wheel drive electric vehicle provided in an embodiment of the present specification;

FIG. 2 is a first schematic flow chart of a power distribution method for a four-wheel drive electric vehicle according to an embodiment of the present disclosure;

fig. 3 is a schematic flow chart of a power distribution method for a four-wheel drive electric vehicle according to an embodiment of the present disclosure;

FIG. 4 is a third schematic flow chart of a power distribution method for a four-wheel drive electric vehicle according to an embodiment of the present disclosure;

FIG. 5 is a fourth schematic flowchart of a power distribution method for a four-wheel drive electric vehicle according to an embodiment of the present disclosure;

FIG. 6 is a fifth schematic flowchart of a power distribution method for a four-wheel drive electric vehicle according to an embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of a power distribution device of a four-wheel drive electric vehicle according to an embodiment of the present disclosure.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the embodiments of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments that can be derived by a person skilled in the art from one or more of the embodiments described herein without making any inventive step shall fall within the scope of protection of this document.

Fig. 1 is a schematic view of an application scenario of a four-wheel drive electric vehicle power distribution method provided in an embodiment of the present specification, as shown in fig. 1, the scenario includes: the system comprises a vehicle control unit positioned on a vehicle, at least two motors (such as a motor 1, a motor 2, … and a motor n shown in figure 1, wherein n is an integer greater than 1) for receiving torque distributed by the vehicle control unit and driving the vehicle to run by using the torque, and a loss power meter. The loss power meter records corresponding loss power of each motor when the motor generates different torques, wherein the loss power is obtained through pre-testing.

Specifically, during the running of the vehicle, the vehicle control unit obtains the required torque of the driver for operating the vehicle and the real-time rotating speed of each motor, for example, during the running of the vehicle, the vehicle control unit may analyze an operation signal of the driver for operating the vehicle and a running state signal of the vehicle to obtain the required torque of the driver for operating the vehicle, where: the operation signal may include: operating at least one of an accelerator pedal, a gear and a brake pedal to generate an operating signal; the operation state signal of the vehicle may include: at least one signal of the running speed and the temperature of the vehicle; the vehicle control unit obtains the loss power of the corresponding motor when different torques are generated at the real-time rotating speed from the loss power meter corresponding to each motor, randomly selects one torque from the obtained torques corresponding to each motor to combine according to the torque sum value as the required torque, and calculates the loss power sum value corresponding to each torque combination; and determining the torque distribution proportion of the required torque in the at least two motors according to the loss power sum value corresponding to each torque combination, so that the loss power sum value corresponding to the determined torque distribution proportion meets the preset requirement.

The power loss when each motor generates different torques may be obtained by performing a bench test on the entire vehicle in advance and stored in a system of the vehicle, such as a vehicle controller or other storage media. For example, before the whole vehicle is taken out of a warehouse, the loss power of each motor generating different torques at different rotating speeds can be obtained through a bench test, and a loss power table can be constructed and stored in a system of the vehicle.

Further, the power loss of the motor when generating torque may include: the motor is in a working state and generates output loss power when outputting torque;

accordingly, the process of arbitrarily selecting one torque from the acquired torques corresponding to each motor to combine according to the torque sum as the required torque, and calculating the loss power sum corresponding to each torque combination may specifically be: and randomly selecting one output torque from the acquired output torques corresponding to each motor to combine according to the torque sum value as the required torque, and calculating the output loss power sum value corresponding to each torque combination.

Alternatively, the power loss when the motor generates torque may include: the motor is in a working state and generates output loss power when outputting torque; the motor is in a non-working state, and the dragging power is generated when the dragging torque is generated;

accordingly, the process of arbitrarily selecting one torque from the acquired torques corresponding to each motor to combine according to the torque sum as the required torque, and calculating the loss power sum corresponding to each torque combination may specifically be: and according to the torque sum value as the required torque, randomly selecting one output torque or dragging torque from the acquired output torque and dragging torque corresponding to each motor to combine, and calculating the loss power sum value corresponding to each torque combination.

Further, when the torque distribution proportion of the required torque in the at least two electric machines is determined according to the loss power sum value corresponding to each torque combination, so that the loss power sum value corresponding to the determined torque distribution proportion meets the preset requirement, one torque combination meeting the preset requirement can be selected from all torque combinations, and the torque distribution proportion corresponding to the torque combination is determined as the torque distribution proportion of the required torque in the at least two electric machines.

Further, in the process of executing the power distribution method for the four-wheel drive electric vehicle, if the loss power of the corresponding motor when the corresponding motor generates different torques at the real-time rotating speed is obtained from the loss power table corresponding to each motor, and all the formed torque combinations cannot meet the preset requirement, after the loss power of the corresponding motor when the corresponding motor generates different torques at the real-time rotating speed is obtained from the loss power table corresponding to each motor, the following steps can be executed: calculating the torque and the loss power corresponding to each acquired motor by adopting a linear interpolation method to obtain corresponding interpolation torque and interpolation loss power; and then, according to the torque sum value as the required torque, randomly selecting one torque from the acquired torque corresponding to each motor and the interpolated torque obtained based on the torques for combination, and calculating the loss power sum value corresponding to each torque combination to finally form the torque combination meeting the preset requirement.

Further, the preset requirements may include: the sum of the power losses corresponding to the determined torque distribution ratios is less than a preset threshold value or is the smallest of the sum of the power losses corresponding to all the torque distribution ratios.

The technical solution of the present specification is further illustrated by the following examples.

Example one

Based on the above application scenario architecture, fig. 2 is a first flowchart illustrating a power distribution method for a four-wheel drive electric vehicle according to an embodiment of the present disclosure, where the method in fig. 2 can be executed by the vehicle control unit in fig. 1, and the four-wheel drive electric vehicle is installed with at least two motors, as shown in fig. 2, the method includes the following steps:

and S102, acquiring the required torque of the driver for operating the vehicle and the real-time rotating speed of the motor during the running of the vehicle.

The required torque of the driver for operating the vehicle reflects the driving intention of the driver for the vehicle, and can be obtained by analyzing the operation behavior of the driver for the vehicle and the running state of the vehicle.

For example, during the running of the vehicle, an operation signal of the driver operating the vehicle and a running state signal of the vehicle are analyzed to obtain the required torque of the driver operating the vehicle.

Wherein the operation signal may include: operating at least one of an accelerator pedal, a gear and a brake pedal to generate an operating signal; the operation state signal of the vehicle may include: at least one of a running speed of the vehicle and a temperature of the vehicle.

Generally, during the running of the vehicle, the real-time rotating speeds of the motors on the same vehicle are the same, and the rotating speeds are consistent with the rotating speeds of the wheels, so that the real-time rotating speeds of the motors can be obtained by monitoring the real-time rotating speeds of the wheels of the vehicle.

And S104, obtaining the loss power of the corresponding motor when different torques are generated at the real-time rotating speed from the loss power meter corresponding to each motor.

In a specific embodiment, in order to conveniently query the loss power of each motor on the vehicle when the motor generates different torques, the loss power of each motor when the motor generates different torques at different rotating speeds can be obtained in advance, and a loss power table corresponding to the corresponding motor is constructed. The power loss table describes the power loss of each motor when the motor generates different torques at different rotation speeds in a discrete value manner.

Based on the method, during the running of the vehicle, after the real-time rotating speed of each motor on the vehicle is obtained, the loss power of each motor when different torques are generated at the real-time rotating speed can be obtained by inquiring the loss power table corresponding to each motor.

And S106, taking the torque sum value as the required torque, randomly selecting one torque from the acquired torques corresponding to each motor to combine, and calculating the loss power sum value corresponding to each torque combination.

After determining the power loss of each motor when different torques are generated at the real-time rotating speed, one torque can be arbitrarily selected from the torques corresponding to each motor to be combined, and the sum of the torques contained in the combination is the required torque. In this combination, a plurality of such torque combinations can be constructed, and each torque combination includes only one torque corresponding to each motor, and the sum of the torques is the above-mentioned required torque. And adding the lost power of the motors in each combination when the motors generate corresponding torque to obtain the corresponding lost power sum value of each combination.

And S108, determining the torque distribution proportion of the required torque in at least two motors according to the loss power sum value corresponding to each torque combination, so that the loss power sum value corresponding to the determined torque distribution proportion meets the preset requirement.

Based on the loss power and the value corresponding to each torque combination, the distribution condition of the corresponding loss power and value when the required torque is distributed in the at least two motors in different torque distribution proportions can be analyzed, and the torque distribution proportion corresponding to the loss power and the value meeting the preset requirement can be determined.

Wherein, the preset requirement may include: the sum of the power losses corresponding to the determined torque distribution ratios is less than a preset threshold value or is the smallest of the sum of the power losses corresponding to all the torque distribution ratios.

In a conventional operation, the vehicle controller generally distributes the required torque of the driver to at least two electric machines on the vehicle by adopting a simple equal proportion or other preset empirical proportions, but the torque distribution mode does not consider the difference of the loss power of each electric machine when different torques are generated, so that the sum of the loss power which is generated at the end and is generated at the same time is higher, and the efficiency of the electric machine system is lower.

In contrast, according to the power distribution method for the four-wheel-drive electric vehicle shown in this embodiment, the vehicle control unit can quickly calculate the torque distribution proportion of the required torque between the motors according to the loss power and the value meeting the preset requirement by obtaining the loss power when the motors generate different torques in advance and setting the condition requirement met by the loss power and the value in advance, so that when the motors receive the torque issued by the vehicle control unit according to the torque distribution proportion to drive the vehicle, the generated loss power and the value meet the preset requirement, and the efficiency of the motor system can be adjusted in a targeted manner.

According to the power distribution method for the four-wheel drive electric vehicle, at least two motors are mounted on the four-wheel drive electric vehicle, and the required torque of a driver for operating the vehicle and the real-time rotating speed of the motors are acquired during the running of the vehicle; obtaining the loss power of the corresponding motor when different torques are generated at the real-time rotating speed from the loss power meter corresponding to each motor; according to the torque sum value as the required torque, randomly selecting one torque from the acquired torques corresponding to each motor to combine, and calculating the loss power sum value corresponding to each torque combination; according to the loss power and the value corresponding to each torque combination, the torque distribution proportion of the required torque in at least two motors is determined, so that the loss power and the value corresponding to the determined torque distribution proportion meet the preset requirement, the power of the whole vehicle is reasonably distributed, the motor system efficiency of the four-wheel-drive electric vehicle is improved, and the adverse effects on energy consumption and endurance are reduced.

Example two

The embodiment expands and supplements the power distribution method of the four-wheel drive electric vehicle shown in fig. 2 on the basis of the first embodiment.

In an embodiment, the power loss of the motor when generating torque may include: the motor is in a working state and generates output loss power when outputting torque; accordingly, as shown in fig. 3, step S106 may include:

s106-2, according to the torque sum value as the required torque, one output torque is selected from the obtained output torques corresponding to each motor to be combined, and the output loss power sum value corresponding to each torque combination is calculated.

The output torque is defined as the torque actively output by the motor in a working state, and can be divided into positive and negative output torques according to different directions of the output torque of the motor; the motor outputs a specified torque in an operating state with a power loss, which is referred to as output loss power in the present embodiment. Table 1 and table 2 correspond to the tables for the loss of output power of the front and rear motors of the vehicle, respectively.

Table 1 front motor output power loss table

TABLE 2 rear motor output power loss table

When the loss power of each motor generating different torques is obtained in advance, each motor can be placed in a working state to obtain the output loss power of each motor generating different output torques at different rotating speeds.

Correspondingly, when the step is realized, one output torque can be selected from the torques generated by each motor at the real-time rotating speed and acquired from the loss power table to be combined according to the torque sum value as the required torque, and the loss power sum value corresponding to each combination is calculated. The sum of the power losses is actually the sum of the output power losses for each combination.

In another embodiment, the power loss of the motor when generating torque may include: the motor is in a working state and generates output loss power when outputting torque; the motor is in a non-working state, and the dragging power is generated when the dragging torque is generated; accordingly, as shown in fig. 4, step S106 may include:

s106-4, according to the torque sum value as the required torque, one output torque or dragging torque is selected randomly from the output torques and dragging torques corresponding to the motors to be combined, and the loss power sum value corresponding to each torque combination is calculated.

Wherein, the definition of the output torque and the output loss power is referred to the above content; the dragging torque is defined as the torque passively generated by the motor in the non-working state, and is the torque that needs to be overcome when the vehicle achieves normal operation, that is, the other motors of the vehicle need to additionally generate power for overcoming the torque, and the power is regarded as a power loss for the other motors as a whole. In the present embodiment, the power at which the drag torque is generated is referred to as drag power, and the drag power can be directly regarded as a loss power. Since the drag torque is the torque that the vehicle needs to overcome in achieving normal operation, it can be equated to a negative output torque in the positive and negative of the torque. Tables 3 and 4 correspond to the drag power loss tables of the front and rear motors of the vehicle, respectively.

Table 3 front motor dragging power meter

Rotational speed r/min	0	50	80	100	120	150	180	200	230	250	280	300	350	400	1350
																Drag power kW	0.00	0.02	0.04	0.05	0.06	0.08	0.10	0.12	0.14	0.16	0.18	0.20	0.24	0.29	2.40
Drag torque Nm	4.7	4.7	4.7	4.9	5.1	5.3	5.5	5.7	5.9	6.0	6.2	6.4	6.7	7.0	17.0

Table 4 rear motor dragging power meter

When the loss power of each motor generating different torques is obtained in advance, each motor can be placed in a working state to obtain the output loss power of each motor generating different output torques at different rotating speeds; and each motor can be placed in a non-working state to obtain the dragging power of each motor when the motor generates dragging torque at different rotating speeds.

Correspondingly, when the step is realized, one torque (output torque or dragging torque) can be selected from the torques generated by each motor at the real-time rotating speed and acquired from the loss power table according to the torque sum value as the required torque, and the loss power sum value corresponding to each combination is calculated.

For example, when only the output torque is included in the combination, the sum of the lost power is actually the sum of the output lost power corresponding to each combination; when both the output torque and the drag torque are included in the combination, the sum of the power loss is actually the sum of the output power loss and the drag power corresponding to each combination.

Further, as shown in fig. 5, the step S108 may include the following steps:

and S108-2, selecting one torque combination meeting the preset requirement from all the torque combinations, and determining the torque distribution proportion corresponding to the torque combination as the torque distribution proportion of the required torque in at least two motors.

For example, after a plurality of combinations constructed by using the torque sum as the required torque are obtained, the loss power sum corresponding to each combination may be screened according to a preset requirement to determine combinations from the combinations, in which the loss power sum satisfies the preset requirement, and then a torque ratio between the electric machines corresponding to one combination is selected from any one of the determined combinations as a torque distribution ratio of the required torque in the at least two electric machines.

In addition, in the process of executing step S108-2, if all the formed torque combinations cannot meet the preset requirement based on the lost power when the corresponding motors generate different torques at the real-time rotation speed obtained from the lost power tables corresponding to the motors, the method steps shown in fig. 6 may be executed to compensate for the problem, that is, after step S104, the following steps are executed:

and S105, calculating the torque and the loss power corresponding to each acquired motor by adopting a linear interpolation method to obtain corresponding interpolation torque and interpolation loss power.

In practical application, because each loss power meter stores the loss power of each motor when different torques are generated at different rotating speeds in a discrete value mode, the loss power meter cannot realize the exhaustion of all data. Therefore, in the process of inquiring the loss power table to obtain the loss power of each motor when generating the torque, the loss power of the motor when generating any torque at any rotating speed can be obtained by calculating the discrete values recorded in the loss power table by adopting a line interpolation method, so that the obtaining requirement of all data is met.

Correspondingly, the step S106 may specifically include:

and S106-6, arbitrarily selecting one torque from the acquired torques corresponding to each motor and the interpolated torques obtained based on the torques to combine according to the torque sum value as the required torque, and calculating the loss power sum value corresponding to each torque combination.

The obtained torque is the torque generated by each motor at the real-time rotating speed and obtained from the loss power table corresponding to each motor, and the interpolated torque is the torque obtained by calculating the torque directly obtained from the loss power table through a meridian interpolation method. When the torques are combined, the two torques can be combined as the torques corresponding to the motors.

The interpolation torque obtained after calculation by the meridian interpolation method participates in the torque combination, and the defect that the torque combination meeting the preset requirement cannot be formed possibly due to the fact that the data volume recorded in the loss power meter is limited can be overcome.

After step S106-6, execution may continue with step S108-2.

Based on the four-wheel drive electric vehicle power distribution method shown in the above embodiment, taking the four-wheel drive electric vehicle with two motors (front and rear motors) as an example, a method for seeking a torque distribution ratio with the minimum total loss power in a practical application scene is given as an example:

for example, the driver-requested required torque is T_dThe real-time rotating speed of the motor is n, and the torque (output torque and dragging torque) of the front motor is T_fAnd the rear motor torque (output torque, drag torque) is T_rThe power loss (output loss power, drag power) of the front motor is P_fThe power loss (output loss power, drag power) of the rear motor is P_rTotal power loss of P_t. Wherein T is_d＝T_f+T_r，P_t＝P_f+P_r. By calculating the total power loss P at all forward and backward torque distribution possibilities_tAnd find such that P_tThe smallest allocation pattern.

Example 1: t is_dWhen n is 200, the front and rear motor power losses under different torque distribution modes are obtained through linear interpolation calculation, and the total power loss table is obtained through summation, wherein n is 200:

TABLE 4 Total Power loss Table

T_d	T_f	T_r	P_f	P_r	P_t
						200.0	206.0	-6.0 (drag)	0.63	0.13	0.76
200.0	200.0	0.0	0.62	0.63	1.25
						200.0	150.0	50.0	0.57	0.71	1.28
200.0	100.0	100.0	0.52	0.79	1.31
						200.0	50.0	150.0	0.47	0.87	1.34
200.0	0.0	200.0	0.41	0.95	1.36
						200.0	-5.7 (drag)	205.7	0.12	0.96	1.08

As can be seen from the table, in this condition, the total power loss is minimal when the rear motor is not operating (i.e., going into a motoring condition), and the front motor outputs 206 Nm.

Example 2: t is_dWhen n is 300 and 2000, the front and rear motor power losses under different torque distribution modes are obtained through linear interpolation calculation, and the total power loss table is obtained through summation:

TABLE 5 Total Power loss Table

T_d	T_f	T_r	P_f	P_r	P_t
						2000.0	2006.0	-6.0 (drag)	5.88	0.13	6.01
2000.0	2000.0	0.0	5.87	0.85	6.72
						2000.0	1900.0	100.0	5.54	1.04	6.58
2000.0	1800.0	200.0	5.21	1.22	6.43
						2000.0	1700.0	300.0	4.87	1.53	6.40
2000.0	1600.0	400.0	4.54	1.66	6.20
						2000.0	1500.0	500.0	4.21	1.91	6.11
2000.0	1400.0	600.0	3.88	2.15	6.03
						2000.0	1300.0	700.0	3.55	2.41	5.96
2000.0	1200.0	800.0	3.21	2.67	5.88
						2000.0	1100.0	900.0	2.88	2.94	5.82
2000.0	1000.0	1000.0	2.55	3.21	5.76
						2000.0	900.0	1100.0	2.31	3.51	5.82
2000.0	800.0	1200.0	2.07	3.81	5.88
						2000.0	700.0	1300.0	1.84	4.10	5.94
2000.0	600.0	1400.0	1.61	4.40	6.01
						2000.0	500.0	1500.0	1.41	4.70	6.11
2000.0	400.0	1600.0	1.21	5.00	6.21
						2000.0	300.0	1700.0	1.02	5.29	6.31
2000.0	200.0	1800.0	0.86	5.59	6.45
						2000.0	100.0	1900.0	0.73	5.89	6.62
2000.0	0.0	2000.0	0.60	6.19	6.79
						2000.0	-5.7 (drag)	2005.7	0.12	6.2	6.32

It can be seen from the table that when the front and rear motors respectively output 1000Nm under the working condition, the total power loss is minimum.

The torque distribution table of the front motor and the rear motor with the minimum total power loss obtained by the method is as follows:

TABLE 6-1 front Motor Torque distribution Table with minimum Total Power loss

TABLE 6-2 rear Motor Torque distribution Table with minimum Total Power loss

And finally, the front motor controller and the rear motor controller respectively control the torque output of the front motor and the rear motor according to the torque distributed in the table by the VCU, so that the power distribution of the whole vehicle is optimized.

EXAMPLE III

On the basis of the same technical concept, the embodiment of the present specification further provides a four-wheel drive electric vehicle power distribution device corresponding to the four-wheel drive electric vehicle power distribution method described in fig. 2 to fig. 6. Fig. 7 is a schematic block composition diagram of a four-wheel drive electric vehicle power distribution device provided in an embodiment of the present specification, where at least two electric motors are installed, the device being configured to perform the four-wheel drive electric vehicle power distribution method described in fig. 2 to 6, and as shown in fig. 7, the device includes:

the data acquisition module 201 is used for acquiring the required torque of a driver for operating the vehicle and the real-time rotating speed of the motor during the running of the vehicle;

the torque acquisition module 202 is used for acquiring the loss power of the corresponding motor when different torques are generated at the real-time rotating speed from the loss power meter corresponding to each motor;

the combination calculation module 203 is used for selecting one torque from the acquired torques corresponding to each motor to be combined according to the torque sum value as the required torque, and calculating the loss power sum value corresponding to each torque combination;

the torque distribution module 204 determines a torque distribution proportion of the required torque in the at least two motors according to the loss power sum value corresponding to each torque combination, so that the loss power sum value corresponding to the determined torque distribution proportion meets a preset requirement.

Alternatively, the power loss of the motor when generating torque may include: the motor is in a working state and generates output loss power when outputting torque;

accordingly, the combination calculation module 203 arbitrarily selects one output torque from the acquired output torques corresponding to each motor to combine, and calculates the sum of the output loss power corresponding to each torque combination, with the sum of the torques as the required torque.

Alternatively, the power loss of the motor when generating torque may include: the motor is in a working state and generates output loss power when outputting torque; the motor is in a non-working state, and the dragging power is generated when the dragging torque is generated;

correspondingly, the combination calculating module 203 selects an output torque or a drag torque from the output torque and the drag torque corresponding to each of the acquired motors to be combined according to the torque sum value as the required torque, and calculates a loss power sum value corresponding to each torque combination.

Optionally, the torque distribution module 204 selects one torque combination satisfying a preset requirement from all the torque combinations, and determines a torque distribution ratio corresponding to the torque combination as a torque distribution ratio of the required torque in the at least two electric machines.

Optionally, the power distribution device for the four-wheel drive electric vehicle may further include:

the interpolation calculation module is used for calculating the acquired torque and loss power corresponding to each motor by adopting a linear interpolation method after acquiring the loss power of the corresponding motor when the corresponding motor generates different torques at the real-time rotating speed from the loss power table corresponding to each motor if the loss power of the corresponding motor when the corresponding motor generates different torques at the real-time rotating speed cannot meet the preset requirement on the basis of all formed torque combinations;

accordingly, the combination calculation module 203 arbitrarily selects one torque from the acquired torques corresponding to each motor and the interpolated torques obtained based on the torques to combine, with the torque sum as the required torque, and calculates the loss power sum corresponding to each torque combination to form the torque combination satisfying the preset requirement. Optionally, the data obtaining module 201 analyzes an operation signal of the vehicle operated by the driver and an operation state signal of the vehicle during the operation of the vehicle, so as to obtain the required torque of the vehicle operated by the driver.

Optionally, the operation signal may include: operating at least one of an accelerator pedal, a gear and a brake pedal to generate an operating signal; the running state signal of the vehicle may include: at least one of a running speed of the vehicle and a temperature of the vehicle.

and the data table building module is used for obtaining the loss power of each motor when different torques are generated at different rotating speeds and building a loss power table corresponding to the corresponding motor.

Optionally, the preset requirement may include: the sum of the power losses corresponding to the determined torque distribution ratios is less than a preset threshold value or is the smallest of the sum of the power losses corresponding to all the torque distribution ratios.

The four-wheel drive electric vehicle power distribution device provided by the embodiment of the specification is provided with at least two motors, and the required torque of a driver for operating the vehicle and the real-time rotating speed of the motors are acquired during the running of the vehicle; obtaining the loss power of the corresponding motor when different torques are generated at the real-time rotating speed from the loss power meter corresponding to each motor; according to the torque sum value as the required torque, randomly selecting one torque from the acquired torques corresponding to each motor to combine, and calculating the loss power sum value corresponding to each torque combination; according to the loss power and the value corresponding to each torque combination, the torque distribution proportion of the required torque in at least two motors is determined, so that the loss power and the value corresponding to the determined torque distribution proportion meet the preset requirement, the power of the whole vehicle is reasonably distributed, the motor system efficiency of the four-wheel-drive electric vehicle is improved, and the adverse effects on energy consumption and endurance are reduced.

It should be noted that the embodiment of the power distribution device for the four-wheel drive electric vehicle in this specification and the embodiment of the power distribution method for the four-wheel drive electric vehicle in this specification are based on the same inventive concept, so that the specific implementation of this embodiment can refer to the implementation of the power distribution method for the four-wheel drive electric vehicle, and repeated details are not repeated.

The foregoing description has been directed to specific embodiments of this disclosure. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may also be possible or may be advantageous.

In the 30 s of the 20 th century, improvements in a technology could clearly be distinguished between improvements in hardware (e.g., improvements in circuit structures such as diodes, transistors, switches, etc.) and improvements in software (improvements in process flow). However, as technology advances, many of today's process flow improvements have been seen as direct improvements in hardware circuit architecture. Designers almost always obtain the corresponding hardware circuit structure by programming an improved method flow into the hardware circuit. Thus, it cannot be said that an improvement in the process flow cannot be realized by hardware physical modules. For example, a Programmable Logic Device (PLD), such as a Field Programmable Gate Array (FPGA), is an integrated circuit whose Logic functions are determined by programming the Device by a user. A digital system is "integrated" on a PLD by the designer's own programming without requiring the chip manufacturer to design and fabricate application-specific integrated circuit chips. Furthermore, nowadays, instead of manually making an Integrated Circuit chip, such Programming is often implemented by "logic compiler" software, which is similar to a software compiler used in program development and writing, but the original code before compiling is also written by a specific Programming Language, which is called Hardware Description Language (HDL), and HDL is not only one but many, such as abel (advanced Boolean Expression Language), ahdl (alternate Hardware Description Language), traffic, pl (core universal Programming Language), HDCal (jhdware Description Language), lang, Lola, HDL, laspam, hardward Description Language (vhr Description Language), vhal (Hardware Description Language), and vhigh-Language, which are currently used in most common. It will also be apparent to those skilled in the art that hardware circuitry that implements the logical method flows can be readily obtained by merely slightly programming the method flows into an integrated circuit using the hardware description languages described above.

The controller may be implemented in any suitable manner, for example, the controller may take the form of, for example, a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro) processor, logic gates, switches, an Application Specific Integrated Circuit (ASIC), a programmable logic controller, and an embedded microcontroller, examples of which include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicone Labs C8051F320, the memory controller may also be implemented as part of the control logic for the memory. Those skilled in the art will also appreciate that, in addition to implementing the controller as pure computer readable program code, the same functionality can be implemented by logically programming method steps such that the controller is in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Such a controller may thus be considered a hardware component, and the means included therein for performing the various functions may also be considered as a structure within the hardware component. Or even means for performing the functions may be regarded as being both a software module for performing the method and a structure within a hardware component.

The systems, devices, modules or units illustrated in the above embodiments may be implemented by a computer chip or an entity, or by a product with certain functions. One typical implementation device is a computer. In particular, the computer may be, for example, a personal computer, a laptop computer, a cellular telephone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

For convenience of description, the above devices are described as being divided into various units by function, and are described separately. Of course, the functions of the units may be implemented in the same software and/or hardware or in multiple software and/or hardware when implementing the embodiments of the present description.

One skilled in the art will recognize that one or more embodiments of the present description may be provided as a method, system, or computer program product. Accordingly, one or more embodiments of the present description may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the description may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The description has been presented with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the description. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium.

Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media 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 technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

One or more embodiments of the present description may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. One or more embodiments of the specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above description is only an example of this document and is not intended to limit this document. Various modifications and changes may occur to those skilled in the art from this document. Any modifications, equivalents, improvements, etc. which come within the spirit and principle of the disclosure are intended to be included within the scope of the claims of this document.

Claims

1. A power distribution method for a four-wheel drive electric vehicle having at least two electric machines mounted thereon, the method comprising:

2. The method of claim 1, wherein the power lost when the motor is generating torque comprises: the motor is in a working state and generates output loss power when outputting torque;

the step of calculating the sum of the loss power corresponding to each torque combination includes the steps of:

and taking the sum of the torques as the required torque, randomly selecting one output torque from the acquired output torques corresponding to each motor to combine, and calculating the sum of the output loss power corresponding to each torque combination.

3. The method of claim 1, wherein the power lost when the motor is generating torque comprises: the motor is in a working state and generates output loss power when outputting torque; the motor is in a non-working state, and the dragging power is generated when the dragging torque is generated;

and taking the sum of the torques as the required torque, randomly selecting one output torque or dragging torque from the output torque and the dragging torque corresponding to each acquired motor for combination, and calculating the sum of the loss power corresponding to each torque combination.

4. The method of claim 1, wherein determining a torque distribution ratio of the required torques in the at least two electric machines according to the power loss sum value corresponding to each torque combination, such that the determined torque distribution ratio satisfies a preset requirement comprises:

and selecting one torque combination meeting the preset requirement from all the torque combinations, and determining the torque distribution proportion corresponding to the torque combination as the torque distribution proportion of the required torque in the at least two motors.

5. The method of claim 4, wherein the method further comprises:

if all the formed torque combinations cannot meet the preset requirement based on the lost power of the corresponding motors when different torques are generated at the real-time rotating speed from the lost power tables corresponding to the motors, after the lost power of the corresponding motors when different torques are generated at the real-time rotating speed is obtained from the lost power tables corresponding to the motors, the method further comprises the following steps:

calculating the torque and the loss power corresponding to each acquired motor by adopting a linear interpolation method to obtain corresponding interpolation torque and interpolation loss power;

and taking the sum of the torques as the required torque, randomly selecting one torque from the acquired torque corresponding to each motor and the interpolated torque obtained based on the torques for combination, and calculating the sum of the loss power corresponding to each torque combination.

6. The method of claim 1, wherein the obtaining the driver's requested torque to operate the vehicle during operation of the vehicle comprises:

during the running of the vehicle, an operation signal of the driver for operating the vehicle and a running state signal of the vehicle are analyzed, and the required torque of the driver for operating the vehicle is obtained.

7. The method of claim 6, wherein the operational signal comprises: operating at least one of an accelerator pedal, a gear and a brake pedal to generate an operating signal; the running state signal of the vehicle includes: at least one of a running speed of the vehicle and a temperature of the vehicle.

8. The method of claim 1, wherein the method further comprises:

and obtaining the loss power of each motor when different torques are generated at different rotating speeds, and constructing the loss power table corresponding to the corresponding motor.

9. The method of claims 1-8, wherein the preset requirements include: the sum of the power losses corresponding to the determined torque distribution ratios is less than a preset threshold value or is the smallest of the sum of the power losses corresponding to all the torque distribution ratios.

10. A four-wheel drive electric vehicle power distribution device, at least two motors are installed on the four-wheel drive electric vehicle, the device comprises: