CN114670669A - Torque distribution method and device for four-wheel drive electric vehicle and electric vehicle - Google Patents

Torque distribution method and device for four-wheel drive electric vehicle and electric vehicle Download PDF

Info

Publication number
CN114670669A
CN114670669A CN202111281806.9A CN202111281806A CN114670669A CN 114670669 A CN114670669 A CN 114670669A CN 202111281806 A CN202111281806 A CN 202111281806A CN 114670669 A CN114670669 A CN 114670669A
Authority
CN
China
Prior art keywords
torque
driving motor
current
distribution
determining
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202111281806.9A
Other languages
Chinese (zh)
Inventor
王琳琳
代康伟
梁海强
储琦
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing Electric Vehicle Co Ltd
Original Assignee
Beijing Electric Vehicle Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Beijing Electric Vehicle Co Ltd filed Critical Beijing Electric Vehicle Co Ltd
Priority to CN202111281806.9A priority Critical patent/CN114670669A/en
Publication of CN114670669A publication Critical patent/CN114670669A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/32—Control or regulation of multiple-unit electrically-propelled vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
    • B60L3/0061—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to electrical machines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/10—Vehicle control parameters
    • B60L2240/12—Speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • B60L2240/423—Torque
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

Abstract

The invention provides a torque distribution method and device for a four-wheel-drive electric automobile and the electric automobile, and relates to the technical field of electric automobiles. The method comprises the following steps: acquiring the current vehicle speed, the first allocation ratio and the maximum output torque of a driving motor; determining the current required torque according to the current vehicle speed; determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output torque of the driving motor; the first distribution ratio is a distribution ratio determined by an accelerator pedal opening degree look-up table; distributing the current required torque to a target required torque of the drive motor based on the optimal torque distribution coefficient. According to the technical scheme, on the premise of the distribution ratio determined by looking up the table of the opening degree of the accelerator pedal, the required torque of the driving motor is dynamically adjusted, so that the driving process is more stable.

Description

Torque distribution method and device for four-wheel drive electric vehicle and electric vehicle
Technical Field
The invention relates to the technical field of electric automobiles, in particular to a torque distribution method and device for a four-wheel drive electric automobile and the electric automobile.
Background
Different from the traditional fuel oil automobile, the electric four-wheel drive automobile does not need to increase a complex four-wheel drive transmission device, omits devices such as an interaxle differential mechanism, a central transfer case, a transmission shaft and the like, can adopt a plurality of motors as power output, and can also adopt a flexible arrangement structure such as a hub motor structure, a single motor structure, a double motor structure and the like. The hub motor structure can save a large amount of space, but can cause the load of the wheel to be increased, reduce the driving safety and has higher cost; the single motor structure is not greatly different from the traditional fuel vehicle, a chassis can be shared, the development difficulty is low, but the whole vehicle structure is complex and the efficiency is low; the double-motor structure can be upgraded based on the existing chassis of the fuel vehicle, the front shaft and the rear shaft can be independently driven, the efficiency of the whole vehicle is high, and the large-scale mass production is facilitated.
At present, a framework of torque distribution and torque filtering processing of the dual-motor electric four-wheel drive vehicle or torque zero-crossing processing are emphasized, but the core content of dual-motor four-wheel drive control, namely the principle that the torque distribution should follow, is not clearly defined, and the high stability and the optimal energy consumption level of the four-wheel drive vehicle cannot be effectively solved.
Disclosure of Invention
The invention aims to provide a torque distribution method and device for a four-wheel-drive electric automobile and the electric automobile, so as to avoid the influence of low distribution efficiency caused by static torque distribution of the four-wheel-drive electric automobile.
To achieve the above object, an embodiment of the present invention provides a torque distribution method for a four-wheel drive electric vehicle, including:
acquiring the current vehicle speed, the first allocation ratio and the maximum output torque of a driving motor;
determining the current required torque according to the current vehicle speed;
determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output torque of the driving motor; the first distribution ratio is a distribution ratio determined by an accelerator pedal opening degree look-up table;
distributing the current required torque to a target required torque of the drive motor based on the optimal torque distribution coefficient.
Optionally, the determining a current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio, and the maximum output torque of the driving motor includes:
determining a preset distribution torque of the driving motor according to the current demand torque and the first distribution ratio;
determining a target output torque of the driving motor according to the preset distribution torque and the maximum output torque;
and determining the current optimal torque distribution coefficient of the driving motor according to the target output torque.
Optionally, the method further includes:
determining the driving state of the four-wheel drive electric vehicle according to the current vehicle speed; the current driving state comprises: driving state and idling state;
if the current driving state is a driving state, determining the optimal torque distribution coefficient of the current driving motor according to the current required torque, the first distribution ratio and the maximum output torque of the driving motor;
if the current driving state is an idle state, acquiring the maximum output efficiency of the driving motor;
and determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output efficiency of the driving motor.
Optionally, the determining a current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio, and the maximum output efficiency of the driving motor includes:
determining a preset distribution torque of the driving motor according to the current demand torque and the first distribution ratio;
acquiring a corresponding relation table of motor torque and motor rotating speed;
determining the preset distribution efficiency of the driving motor according to the preset distribution torque of the driving motor and the corresponding relation table;
Determining target output efficiency of the driving motor according to the preset distribution efficiency and the maximum output efficiency;
and determining the current optimal torque distribution coefficient of the driving motor according to the target output efficiency.
Optionally, obtaining the maximum output torque of the driving motor includes:
acquiring a normal reaction force and a tangential reaction force of a driving motor;
and determining the maximum output torque of the driving motor according to the normal reaction force and the tangential reaction force.
Optionally, acquiring the normal reaction force and the tangential reaction force of the driving motor comprises:
acquiring preset parameter information of the four-wheel drive electric vehicle; the preset parameter information includes: the normal reaction force of the static axle load of the driving motor, the air lift force of the driving motor, the gravity of the four-wheel drive electric automobile, the mass center height of the four-wheel drive electric automobile and the ground adhesion coefficient;
and determining the normal reaction force and the tangential reaction force of the driving motor according to the preset parameter information of the four-wheel drive electric automobile.
Optionally, the method further includes:
and determining that the higher the normal reaction force is, the larger the torque proportion of the corresponding driving motor is according to the normal reaction force.
Optionally, the method further includes:
acquiring motor state parameters of a driving motor, and judging whether the driving motor has a driving fault or not;
if yes, the optimal torque distribution coefficient is determined as the torque proportion which is output to distribute all the torque for driving the normal motor.
To achieve the above object, an embodiment of the present invention further provides a torque distribution device for a four-wheel drive electric vehicle, including:
the acquisition module is used for acquiring the current vehicle speed, the first distribution ratio and the maximum output torque of the driving motor;
the first determining module is used for determining the current required torque according to the current vehicle speed;
the second determination module is used for determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output torque of the driving motor; the first distribution ratio is a distribution ratio determined by an accelerator pedal opening degree look-up table;
and the distribution module is used for distributing the current required torque to the target required torque of the driving motor based on the optimal torque distribution coefficient.
In order to achieve the above object, an embodiment of the present invention further provides an electric vehicle, including the torque distribution device of the four-wheel drive electric vehicle as described above.
The technical scheme of the invention has the following beneficial effects:
in the technical scheme, the first allocation ratio is determined by looking up a table according to the opening degree of the accelerator pedal, the first allocation ratio is readjusted according to the current vehicle speed and the maximum output torque of the driving motor, namely, the optimal torque distribution coefficient of the current driving motor is determined, and finally, the current required torque is distributed to the target required torque of the driving motor based on the optimal torque distribution coefficient. The invention realizes dynamic adjustment of the distribution coefficient, realizes reappearance adjustment of the first distribution ratio under the condition that the first distribution ratio is reasonable without distributing torque, and avoids unstable phenomena such as wheel slipping or locking caused by unbalanced torque distribution.
Drawings
FIG. 1 is a schematic flow chart illustrating a torque distribution method for a four-wheel drive electric vehicle according to an embodiment of the present invention;
fig. 2 is a schematic block diagram of a torque distribution device of a four-wheel drive electric vehicle according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
In various embodiments of the present invention, it should be understood that the sequence numbers of the following processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
In addition, the terms "system" and "network" are often used interchangeably herein.
In the embodiments provided herein, it should be understood that "B corresponding to a" means that B is associated with a from which B can be determined. It should also be understood that determining B from a does not mean determining B from a alone, but may be determined from a and/or other information.
The invention provides a torque distribution method and device of a four-wheel drive electric vehicle and the electric vehicle, aiming at the problem of low distribution efficiency caused by static torque distribution of the four-wheel drive electric vehicle. For a four-wheel drive electric vehicle, the basic principle is to realize optimization of system efficiency on the premise of ensuring the running stability of the whole vehicle, namely, on one hand, the torque of a front driving motor or a rear driving motor needs to be reasonably distributed to avoid instability phenomena such as wheel slipping or locking, and on the other hand, the motor efficiency of double motors needs to be comprehensively considered to realize overall optimization.
As shown in fig. 1, a torque distribution method for a four-wheel drive electric vehicle according to an embodiment of the present invention includes:
step 100, obtaining a current vehicle speed, a first distribution ratio and a maximum output torque of a driving motor;
the implementation main body of the embodiment is a vehicle control unit, the vehicle control unit controls the front motor to output torque through the front motor controller, and similarly, the vehicle control unit controls the rear motor to output torque through the rear motor controller. Based on the structure, the maximum output torque of the driving motor is obtained, namely the maximum output torque of the front driving motor and the maximum output torque of the rear driving motor are respectively obtained.
Step 200, determining the current demand torque according to the current vehicle speed;
step 300, determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output torque of the driving motor; the first distribution ratio is a distribution ratio determined by an accelerator pedal opening degree look-up table;
in this embodiment, the first allocation ratio and the current required torque obtained in steps 100 and 200 may satisfy the allocation of the first torque, because the first allocation ratio is an allocation ratio determined by a look-up table of accelerator pedal opening degrees, that is, an allocation coefficient of the allocation ratio is fixed, that is, a torque ratio of the front and rear driving motors is allocated according to the first allocation ratio regardless of the current required state; the comparison with the maximum output torque of the driving motor is added, so that the first distribution ratio is modified to obtain the current optimal torque distribution coefficient of the driving motor, and the torque proportion of the front driving motor and the rear driving motor is determined according to the current demand states in different scenes.
It should be noted that the current demand state may have any one or any combination of motor failure, power limitation, demand stability, demand dynamics, and demand economy, for example. Therefore, the current demand state can be determined according to the motor state parameters and the driving state parameters; and setting the current demand state with the highest priority as a function demand state, and outputting the torque proportion of the front and rear driving motors corresponding to the function demand state. As a preferred embodiment, priority order may be set for all the current demand states, and the front-to-rear torque ratio may be set according to one of the current demand states having the highest priority.
And 400, distributing the current required torque to the target required torque of the driving motor based on the optimal torque distribution coefficient.
In this embodiment, the current required torque is distributed in real time based on the optimal torque distribution coefficient, and the optimal torque distribution coefficient is determined according to the current required state of the four-wheel drive electric vehicle in actual running, so that the motor control realized according to the optimal torque distribution coefficient can flexibly adjust the vehicle state. Therefore, the torque proportion of the front and rear driving motors can be reasonably adjusted according to the actual running condition of the four-wheel drive electric automobile.
Optionally, the step 300 includes:
step 310, determining a preset distribution torque of the driving motor according to the current required torque and the first distribution ratio;
here, a preset distribution torque distributed in the case of the first distribution ratio is determined first from the current demand torque and the first distribution ratio. Step 320, determining a target output torque of the driving motor according to the preset distribution torque and the maximum output torque;
here, the maximum output torque of the front driving motor and the maximum output torque of the rear driving motor are determined among the maximum output torques that have been acquired, and the preset distribution torques of the front and rear driving motors that preset distribution torques one by one are compared, thereby determining the final target output torque.
And 330, determining the current optimal torque distribution coefficient of the driving motor according to the target output torque.
In this embodiment, the optimal torque distribution coefficient of the current drive motor is determined based on the determined front and rear target output torques. For example: when accelerating, if the total driving torque is 400Nm and the distribution ratio is 50:50, 200Nm should be distributed to the front and rear driving motors respectively, if the current maximum allowable driving force of the front axle is 150Nm and the rear axle is 200Nm, 150Nm of the front driving motor and 250Nm of the rear driving motor are determined, and the current optimal torque distribution coefficient of the driving motors is determined according to the target output torque, so that the torques of the front and rear driving motors are ensured to be within the allowable range, and the slip phenomenon can be prevented as far as possible.
It should be noted that, in the above steps, when stability is maintained during vehicle driving, the current optimal torque distribution coefficient of the driving motor is determined, and on the other hand, the motor efficiency of the dual motors is considered comprehensively to achieve overall optimization.
Optionally, the method further includes:
step 410, determining the driving state of the four-wheel drive electric vehicle according to the current vehicle speed; the current driving state comprises: driving state and idling state;
step 420, if the current driving state is the driving state, executing step 300;
step 430, if the current driving state is an idle state, acquiring the maximum output efficiency of the driving motor; here, the idling state is a low speed state during driving.
And step 440, determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output efficiency of the driving motor.
In this embodiment, in the vehicle in the idling state, it is considered that the motor efficiency is optimized. The basic idea of the principle of optimizing the motor efficiency is to concentrate the operating points of the motor as much as possible in the operating area with higher motor efficiency based on the corresponding relation table of the motor torque and the motor rotation speed, that is, determine the optimal torque distribution coefficient of the current driving motor according to the current required torque, the first distribution ratio and the maximum output efficiency of the driving motor, and preferably consider whether the current output efficiency is optimal or not, so as to adjust the first distribution ratio.
Specifically, the step 440 includes:
step 441, determining a preset distribution torque of the driving motor according to the current required torque and the first distribution ratio;
step 442, acquiring a corresponding relation table of the motor torque and the motor rotating speed;
in the table of correspondence between motor torque and motor speed, the motor efficiency is low at low rotational speed and low total driving torque, and the motor efficiency is high at medium-high rotational speed and medium-high torque, so the basic idea of motor efficiency principle distribution is to maintain the operating point of the motor in a high efficiency region, where the data of low rotational speed, low total driving torque, medium-high rotational speed and medium-high torque are all calibrated according to experiments, and no limitation is made here.
Step 443, determining a preset distribution efficiency of the driving motor according to a preset distribution torque of the driving motor and the corresponding relation table;
step 444, determining target output efficiency of the driving motor according to the preset distribution efficiency and the maximum output efficiency;
and step 445, determining the current optimal torque distribution coefficient of the driving motor according to the target output efficiency.
Here, it is preferable that the models of the front and rear drive motors are identical. It should be noted that, when the motor rotation speed is low (e.g. 500rpm), if the total torque demand requested by the driver is 50Nm (drive motor end torque), at this time, if 50Nm (drive motor end torque) is equally distributed to the two drive motors, the torque that each motor needs to execute is 25Nm, and it can be known by combining the 500rpm rotation speed and the correspondence table that the efficiency of the two motors is lower than that of 50Nm, so the optimal state should be that a single drive motor (front or rear drive motor) works, so that the single drive motor works in a high efficiency region, thereby avoiding the lower comprehensive efficiency when the two drive motors work simultaneously.
Therefore, based on the driving stability principle (step 100 to step 300) and the motor efficiency principle (step 410 to step 440), when executing the torque distribution strategy of the four-wheel drive electric vehicle, the driving stability principle should be used as a boundary condition, and the motor efficiency principle should be used as a specific control condition, so as to ensure that the vehicle can achieve better economy on a stable basis.
Optionally, the obtaining of the maximum output torque of the driving motor in step 100 includes:
acquiring a normal reaction force and a tangential reaction force of a driving motor;
and determining the maximum output torque of the driving motor according to the normal reaction force and the tangential reaction force.
It should be noted that, when the vehicle accelerates on a horizontal road, the vehicle load will be transferred to the rear axle, whereas when the vehicle decelerates, the vehicle load will be transferred to the front axle, so the maximum output torque of the driving motor is determined according to the normal reaction force and the tangential reaction force.
Specifically, the method further comprises:
and determining that the higher the normal reaction force is, the larger the torque proportion of the corresponding driving motor is according to the normal reaction force.
In this embodiment, the larger the normal force of the front and rear driving motors is, the larger the allowable driving force is, otherwise, instability such as wheel slip occurs. Therefore, the basic principle based on the principle of running stability is that the distributed torques of the front and rear driving motors cannot exceed the road adhesion limit, so that the vehicle instability is avoided.
Specifically, acquiring a normal reaction force and a tangential reaction force of a driving motor includes:
acquiring preset parameter information of the four-wheel drive electric vehicle; the preset parameter information includes: the normal reaction force of the static axle load of the driving motor, the air lift force of the driving motor, the gravity of the four-wheel drive electric automobile, the mass center height of the four-wheel drive electric automobile and the ground adhesion coefficient;
and determining the normal reaction force and the tangential reaction force of the driving motor according to the preset parameter information of the four-wheel drive electric automobile.
In this embodiment, the normal reaction force and the tangential reaction force of the drive motor may be determined according to equations 1 to 4.
Equation 1:
Figure BDA0003331371370000081
equation 2:
Figure BDA0003331371370000082
equation 3: fX1≤FZ1μ；
Equation 4: fX2≤FZ2μ；
Wherein, FZ1、FZ2Normal reaction force of static axle load corresponding to the front wheel and the rear wheel; fZs1、FZs2Normal reaction force of static axial load; fZw1、FZw2The air lift force of the front and rear driving motors; g is the gravity of the four-wheel drive electric automobile; h isgThe mass center of the four-wheel drive electric automobile is high; l is the automobile wheel base; fX1、FX2Tangential reaction forces corresponding to the front wheel and the rear wheel; mu is the ground adhesion coefficient.
In the embodiment, the normal reaction force and the tangential reaction force of the driving motor can be determined according to the formula, so that the maximum output torque of the driving motor can be determined, and the accuracy of calculating the optimal torque distribution coefficient is ensured.
Optionally, the method further includes:
acquiring motor state parameters of a driving motor, and judging whether the driving motor has a driving fault or not;
if yes, determining the optimal torque distribution coefficient as a torque proportion for distributing all the torque for the normally-driven motor.
Aiming at the motor state parameter of motor fault, the torque distribution method comprises the following steps: and determining the optimal torque distribution coefficient as a torque proportion for distributing all the torque for the motor which drives normally. That is, a single motor is used for driving, two different states of the front motor and the rear motor which are separately driven are further distinguished, and the motion state of the vehicle is controlled, wherein the torque distribution ratio is 0: 100 or 100: 0.
specifically, the Vehicle is provided with a Vehicle Control Unit (VCU), a battery controller, a front drive motor controller, a rear drive motor, and a rear drive motor controller. In the control strategy, a VCU (virtual vehicle Unit) needs to judge whether the whole vehicle is in a fault state or not according to the motor states fed back by front and rear motor controllers through a CAN (controller area network) network and whether a front and rear axle torque distribution strategy in the fault state needs to be executed or not; if the motor is not in the fault state, the next judgment is carried out, otherwise, the front and rear axle torque distribution coefficients are calculated according to the front and rear axle torque distribution strategy in the fault state, the VCU calculates the torque request of the front and rear motors at the moment and sends the torque request to the front and rear motor controllers through the CAN network, and the front and rear motor controllers respond to the torque request of the VCU.
In conclusion, based on the principle of driving stability, the phenomena of wheel slipping and locking can be effectively avoided, and the stability and the safety of the whole vehicle are improved; based on the principle of driving stability, the road adhesion grade can be fully utilized, and the acceleration and the dynamic property of the whole vehicle are effectively improved; based on the principle of motor efficiency, the torque can be reasonably distributed to the front driving motor and the rear driving motor, the efficiency of the front driving motor and the efficiency of the rear driving motor are fully utilized, and the best economy of the whole vehicle is realized.
As shown in fig. 2, an embodiment of the present invention further provides a torque distribution device for a four-wheel drive electric vehicle, including:
the acquisition module 10 is used for acquiring the current vehicle speed, the first allocation ratio and the maximum output torque of the driving motor;
the first determination module 20 is used for determining the current required torque according to the current vehicle speed;
the second determining module 30 is configured to determine an optimal torque distribution coefficient of the current driving motor according to the current required torque, the first distribution ratio, and the maximum output torque of the driving motor; the first distribution ratio is a distribution ratio determined by an accelerator pedal opening degree look-up table;
a distributing module 40 for distributing the current required torque to the target required torque of the driving motor based on the optimal torque distribution coefficient.
Optionally, the second determining module 30 includes:
the first determining unit is used for determining the preset distribution torque of the driving motor according to the current demand torque and the first distribution ratio;
a second determination unit, configured to determine a target output torque of the driving motor according to the preset distribution torque and the maximum output torque;
and the third determining unit is used for determining the current optimal torque distribution coefficient of the driving motor according to the target output torque.
Optionally, the apparatus further comprises:
the third determining module is used for determining the driving state of the four-wheel-drive electric vehicle according to the current vehicle speed; the current driving state comprises: driving state and idling state;
the first processing module is used for determining the optimal torque distribution coefficient of the current driving motor according to the current required torque, the first distribution ratio and the maximum output torque of the driving motor if the current driving state is the driving state;
the second obtaining module is used for obtaining the maximum output efficiency of the driving motor if the current driving state is an idle state;
and the second processing module is used for determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output efficiency of the driving motor.
Optionally, the second processing module includes:
the fourth determining unit is used for determining the preset distribution torque of the driving motor according to the current demand torque and the first distribution ratio;
the first acquisition unit is used for acquiring a corresponding relation table of motor torque and motor rotating speed;
the fifth determining unit is used for determining the preset distribution efficiency of the driving motor according to the preset distribution torque of the driving motor and the corresponding relation table;
a sixth determining unit, configured to determine a target output efficiency of the driving motor according to the preset distribution efficiency and the maximum output efficiency;
and the seventh determining unit is used for determining the current optimal torque distribution coefficient of the driving motor according to the target output efficiency.
Optionally, the obtaining module 10 includes:
a second acquisition unit for acquiring a normal reaction force and a tangential reaction force of the drive motor;
and the eighth determining unit is used for determining the maximum output torque of the driving motor according to the normal reaction force and the tangential reaction force.
Optionally, the second obtaining unit includes:
the first acquisition subunit is used for acquiring preset parameter information of the four-wheel drive electric vehicle; the preset parameter information includes: the normal reaction force of the static axle load of the driving motor, the air lift force of the driving motor, the gravity of the four-wheel drive electric automobile, the mass center height of the four-wheel drive electric automobile and the ground adhesion coefficient;
And the first determining subunit is used for determining the normal reaction force and the tangential reaction force of the driving motor according to the preset parameter information of the four-wheel drive electric automobile.
Optionally, the apparatus further comprises:
and the third processing module is used for determining that the higher the normal reaction force is, the larger the torque proportion of the corresponding driving motor is according to the normal reaction force.
Optionally, the apparatus further comprises:
the fourth processing module is used for acquiring motor state parameters of the driving motor and judging whether the driving motor has driving faults or not;
if yes, the optimal torque distribution coefficient is determined as the torque proportion which is output to distribute all the torque for driving the normal motor.
The embodiment of the invention also provides an electric automobile which comprises the torque distribution device of the four-wheel drive electric automobile.
In embodiments of the present invention, modules may be implemented in software for execution by various types of processors. An identified module of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions which may, for instance, be constructed as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but may comprise disparate instructions stored in different bits which, when joined logically together, comprise the module and achieve the stated purpose for the module.
Indeed, a module of executable code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Likewise, operational data may be identified within the modules and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.
When a module can be implemented by software, considering the level of existing hardware technology, a module implemented by software may build a corresponding hardware circuit to implement a corresponding function, without considering cost, and the hardware circuit may include a conventional Very Large Scale Integration (VLSI) circuit or a gate array and an existing semiconductor such as a logic chip, a transistor, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.
The exemplary embodiments described above are described with reference to the drawings, and many different forms and embodiments of the invention may be made without departing from the spirit and teaching of the invention, therefore, the invention is not to be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of elements may be exaggerated for clarity. The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Unless otherwise indicated, a range of values, when stated, includes the upper and lower limits of the range and any subranges therebetween.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (10)

1. A torque distribution method for a four-wheel drive electric vehicle is characterized by comprising the following steps:
acquiring the current vehicle speed, the first allocation ratio and the maximum output torque of a driving motor;
determining the current required torque according to the current vehicle speed;
determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output torque of the driving motor; the first distribution ratio is a distribution ratio determined by an accelerator pedal opening degree look-up table;
distributing the current required torque to a target required torque of the drive motor based on the optimal torque distribution coefficient.
2. The method of claim 1, wherein determining a current optimal torque distribution coefficient for the drive motor based on the current requested torque, the first distribution ratio, and the drive motor maximum output torque comprises:
Determining a preset distribution torque of the driving motor according to the current demand torque and the first distribution ratio;
determining a target output torque of the driving motor according to the preset distribution torque and the maximum output torque;
and determining the current optimal torque distribution coefficient of the driving motor according to the target output torque.
3. The method of claim 1, further comprising:
determining the driving state of the four-wheel drive electric vehicle according to the current vehicle speed; the current driving state comprises: driving state and idling state;
if the current driving state is a driving state, determining the optimal torque distribution coefficient of the current driving motor according to the current required torque, the first distribution ratio and the maximum output torque of the driving motor;
if the current driving state is an idle state, acquiring the maximum output efficiency of the driving motor;
and determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output efficiency of the driving motor.
4. The method of claim 3, wherein determining a current optimal torque distribution coefficient for the drive motor based on the current requested torque, the first distribution ratio, and a maximum output efficiency of the drive motor comprises:
Determining a preset distribution torque of the driving motor according to the current demand torque and the first distribution ratio;
acquiring a corresponding relation table of motor torque and motor rotating speed;
determining the preset distribution efficiency of the driving motor according to the preset distribution torque of the driving motor and the corresponding relation table;
determining the target output efficiency of the driving motor according to the preset distribution efficiency and the maximum output efficiency;
and determining the current optimal torque distribution coefficient of the driving motor according to the target output efficiency.
5. The method of claim 1, wherein obtaining a drive motor maximum output torque comprises:
acquiring a normal reaction force and a tangential reaction force of a driving motor;
and determining the maximum output torque of the driving motor according to the normal reaction force and the tangential reaction force.
6. The method of claim 5, wherein obtaining normal and tangential reaction forces of a drive motor comprises:
acquiring preset parameter information of the four-wheel drive electric vehicle; the preset parameter information includes: the normal reaction force of the static axle load of the driving motor, the air lift force of the driving motor, the gravity of the four-wheel drive electric automobile, the mass center height of the four-wheel drive electric automobile and the ground adhesion coefficient;
And determining the normal reaction force and the tangential reaction force of the driving motor according to the preset parameter information of the four-wheel drive electric automobile.
7. The method of claim 5, further comprising:
and determining that the higher the normal reaction force is, the larger the torque proportion of the corresponding driving motor is according to the normal reaction force.
8. The method of claim 1, further comprising:
acquiring motor state parameters of a driving motor, and judging whether the driving motor has a driving fault or not;
if yes, the optimal torque distribution coefficient is determined as the torque proportion which is output to distribute all the torque for driving the normal motor.
9. A torque distribution device for a four-wheel drive electric vehicle, comprising:
the acquisition module is used for acquiring the current vehicle speed, the first allocation ratio and the maximum output torque of the driving motor;
the first determining module is used for determining the current required torque according to the current vehicle speed;
the second determination module is used for determining the current optimal torque distribution coefficient of the driving motor according to the current required torque, the first distribution ratio and the maximum output torque of the driving motor; the first distribution ratio is a distribution ratio determined by an accelerator pedal opening degree look-up table;
And the distribution module is used for distributing the current required torque to the target required torque of the driving motor based on the optimal torque distribution coefficient.
10. An electric vehicle characterized by comprising the torque distribution device of the four-wheel drive electric vehicle as claimed in claim 9.
CN202111281806.9A 2021-11-01 2021-11-01 Torque distribution method and device for four-wheel drive electric vehicle and electric vehicle Pending CN114670669A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111281806.9A CN114670669A (en) 2021-11-01 2021-11-01 Torque distribution method and device for four-wheel drive electric vehicle and electric vehicle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111281806.9A CN114670669A (en) 2021-11-01 2021-11-01 Torque distribution method and device for four-wheel drive electric vehicle and electric vehicle

Publications (1)

Publication Number Publication Date
CN114670669A true CN114670669A (en) 2022-06-28

Family

ID=82070699

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111281806.9A Pending CN114670669A (en) 2021-11-01 2021-11-01 Torque distribution method and device for four-wheel drive electric vehicle and electric vehicle

Country Status (1)

Country Link
CN (1) CN114670669A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106515509A (en) * 2017-01-03 2017-03-22 重庆长安汽车股份有限公司 Driving system for electric four-wheel-drive vehicle and torque distribution method of driving system
CN108248453A (en) * 2016-12-27 2018-07-06 比亚迪股份有限公司 Identify road surface method, apparatus and automobile
CN111746295A (en) * 2019-03-29 2020-10-09 北京新能源汽车股份有限公司 Distributed drive control method and device for electric automobile
WO2021171050A1 (en) * 2020-02-26 2021-09-02 日産自動車株式会社 Method for controlling electric vehicle, and electric vehicle

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108248453A (en) * 2016-12-27 2018-07-06 比亚迪股份有限公司 Identify road surface method, apparatus and automobile
CN106515509A (en) * 2017-01-03 2017-03-22 重庆长安汽车股份有限公司 Driving system for electric four-wheel-drive vehicle and torque distribution method of driving system
CN111746295A (en) * 2019-03-29 2020-10-09 北京新能源汽车股份有限公司 Distributed drive control method and device for electric automobile
WO2021171050A1 (en) * 2020-02-26 2021-09-02 日産自動車株式会社 Method for controlling electric vehicle, and electric vehicle

Similar Documents

Publication Publication Date Title
CN108602452B (en) Controller and method for a motor vehicle
US6867509B1 (en) Control apparatus for transmission-equipped hybrid vehicle, and control method for the same
CN110014851B (en) Method for distributing torque between front and rear double-motor four-wheel drive vehicle axles
US11254220B2 (en) Controller for a motor vehicle and method
US20050099146A1 (en) Hybrid vehicle
CN104175902A (en) Torque distribution control method for electric-wheel automobile hub motor torque distribution system
WO2023138608A1 (en) Vehicle start control method and apparatus, and vehicle
US20080249695A1 (en) Torque split strategy for a belt alternator starter (bas) hybrid
CN108454615B (en) A kind of planet parallel-serial hybrid power driver demand torque estimation method
CN108248599A (en) Hydraulic hybrid regeneration brake system and control method based on double accumulators
CN108297736A (en) A kind of bi-motor distributed-driving electric automobile and motor control strategy
CN109240125B (en) Method for calculating two-shaft required torque of gearbox of hybrid vehicle
CN111002867A (en) Electric power distribution method and device of hybrid power system and hybrid power automobile
CN108177649B (en) Gear shifting method and device for hybrid electric vehicle
CN112622634B (en) Torque control method and system of electric automobile
WO2023169314A1 (en) Four-wheel drive hybrid vehicle control method and apparatus, vehicle, and storage medium
CN114670669A (en) Torque distribution method and device for four-wheel drive electric vehicle and electric vehicle
JP2021164365A (en) Vehicular control device
CN111332275A (en) Engineering vehicle distributed control system and control method
US9789864B2 (en) Devices and methods for distributing an overall target torque specification
CN108725427B (en) Control method for auxiliary engine stop of clutch-free hybrid electric vehicle brake
CN105460005A (en) System and method for controlling powertrain in vehicle
CN113753014B (en) Engine and ISG coordinated speed regulation control method in gear shifting process under hybrid architecture
JP2006312959A (en) Power generation control method and engine control device
CN114103623B (en) Pure electric mode torque distribution method of dual-motor hybrid drive system

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination