CN114954027A - Control method and device for motor of electric automobile and vehicle - Google Patents

Control method and device for motor of electric automobile and vehicle Download PDF

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Publication number
CN114954027A
CN114954027A CN202110819569.0A CN202110819569A CN114954027A CN 114954027 A CN114954027 A CN 114954027A CN 202110819569 A CN202110819569 A CN 202110819569A CN 114954027 A CN114954027 A CN 114954027A
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China
Prior art keywords
torque
wheel speed
speed difference
safety
motor
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CN202110819569.0A
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Chinese (zh)
Inventor
张庆祝
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Great Wall Motor Co Ltd
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Great Wall Motor Co Ltd
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Priority to CN202110819569.0A priority Critical patent/CN114954027A/en
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    • 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
    • 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
    • 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
    • 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
    • B60L2240/46—Drive Train control parameters related to wheels
    • B60L2240/461—Speed
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The embodiment of the application relates to the technical field of automobiles, in particular to a control method and device for a motor of an electric automobile and a vehicle. Detecting wheel speed differences at two ends of a differential, and acquiring the maximum available torque of the motor according to the wheel speed differences of the wheel speeds at the two ends of the differential when the wheel speed differences are larger than or equal to a preset threshold; determining a safety pre-estimated torque according to the wheel speed difference and the maximum available torque; and outputting the safety predicted torque to a vehicle controller of the vehicle controller so as to reduce the current torque of the motor to the safety predicted torque. When the wheel speed difference is larger than or equal to the preset threshold value, the current torque and the wheel speed difference at two ends are larger, and the differential is easily damaged, so that the safety pre-estimated torque capable of enabling the differential to safely operate is calculated through the wheel speed difference, then the safety pre-estimated torque is output, the motor is driven to reduce the torque to the safety pre-estimated torque, the wheel speed difference at two ends is reduced, and the differential is protected.

Description

Control method and device for motor of electric automobile and vehicle
Technical Field
The embodiment of the application relates to the technical field of automobiles, in particular to a control method and device for a motor of an electric automobile and a vehicle.
Background
With the rapid development of new energy automobiles, driving motors with different powers and different rotating speed categories are widely applied, and besides hub motors, electric driving systems are equipped with reduction boxes for reducing speed and increasing torque. In order to reduce tire wear, downshift power and fuel consumption, enhance vehicle steering and braking capability, and be affected by cost, reduction gearboxes are generally equipped with differentials without differential locks. When the difference between the wheel speeds on the two sides is too large and the output torque of the motor is larger, the differential mechanism is damaged
In the prior art, the torque is generally limited by directly monitoring the torque by the vehicle controller, so that the interaction process of the vehicle controller about the torque is complex, and the defects that the method is difficult to realize, the calibration and debugging time of the whole vehicle is long and the like are caused.
Content of application
The embodiment of the application provides a control method and device for a motor of an electric automobile and a vehicle, and aims to solve the problem that the interaction process of a vehicle controller on torque is complex.
In a first aspect of the embodiments of the present application, a control method for a motor of an electric vehicle is provided, where the control method includes, based on a drive motor controller:
detecting wheel speed difference at two ends of a differential, and acquiring the maximum available torque of the motor according to the wheel speed difference when the wheel speed difference is greater than or equal to a preset threshold value;
determining a safe estimated torque according to the wheel speed difference and the maximum available torque;
and outputting the safe estimated torque to a vehicle controller of the vehicle controller so as to reduce the current torque of the motor to the safe estimated torque.
Optionally, determining a maximum available torque of the electric machine based on a wheel speed difference between the wheel speeds at the two ends of the differential, comprises:
determining the wheel speed difference of the wheel speeds of the two ends according to the wheel speeds of the two ends of the differential;
determining the maximum available torque corresponding to the wheel speed difference in a preset torque outer characteristic curve.
Optionally, determining a safe predicted torque according to the wheel speed difference and the maximum available torque comprises:
determining a torque limit coefficient and a time coefficient of the differential according to the wheel speed difference and a timer;
and determining the safety estimated torque of the differential according to the maximum available torque, the torque limiting coefficient and the time coefficient.
Optionally, determining a torque limit coefficient and a time coefficient of the differential according to the wheel speed difference comprises:
substituting the wheel speed difference into a torque limiting coefficient chart to obtain the torque limiting coefficient corresponding to the wheel speed difference;
and when the wheel speed difference is larger than or equal to a preset threshold value, timing is started until the safety pre-estimated torque is determined, a time value is obtained, and the time value is substituted into a time coefficient chart to obtain the time coefficient corresponding to the time value.
Optionally, determining a safe predicted torque of the differential according to the maximum available torque, the torque limit coefficient and the time coefficient, includes:
and multiplying the maximum available torque, the torque limiting coefficient and the time coefficient to obtain the safety estimated torque of the differential.
Optionally, determining a safe predicted torque of the differential according to the maximum available torque, the torque limit coefficient and the time coefficient includes:
and multiplying the maximum available torque, the torque limiting coefficient and the time coefficient to obtain the safety estimated torque.
Optionally, outputting the safety predicted torque to a vehicle controller of a vehicle control unit so that the current torque of the motor is reduced to the safety predicted torque, including:
outputting the safety estimated torque to a vehicle control unit;
receiving a safety pre-estimated torque request returned by the vehicle control unit aiming at the safety pre-estimated torque;
and responding to the safety predicted torque request, and driving a motor to output the safety predicted torque based on the safety predicted torque reduction torque.
Optionally, after the motor controller reduces the output torque, the control method further includes:
and when the wheel speed difference is lower than a preset threshold value, outputting a preset torque to the vehicle controller so that a motor of the vehicle outputs the torque according to the preset torque, wherein the preset torque is a motor pre-execution torque which is not corrected according to the wheel speed difference.
A second aspect of the embodiments of the present application provides a control device for a motor of an electric vehicle, the control device including:
the acquisition module is used for detecting the wheel speeds at two ends of the differential mechanism, and acquiring the maximum available torque of the motor according to the wheel speed difference of the wheel speeds at the two ends of the differential mechanism when the wheel speed difference is greater than or equal to a preset threshold value;
the determining module is used for determining a safety estimated torque according to the wheel speed difference and the maximum available torque;
and the execution module is used for outputting the safety estimated torque to the vehicle controller of the vehicle controller so as to reduce the current torque of the motor to the safety estimated torque.
A third aspect of the embodiments of the present application provides an electronic device, including:
a memory for storing a computer program;
a processor for executing a computer program stored on the memory to implement the control method of any one of claims 1-7.
A fourth aspect of the embodiments of the present application provides a vehicle, characterized by comprising a control device configured to implement the control method described above.
Has the advantages that:
the application provides a control method and device for a motor of an electric automobile and a vehicle, wherein wheel speeds at two ends of a vehicle differential mechanism are obtained in real time in the vehicle running process, so that wheel speed differences at two ends are obtained, when the wheel speed differences are larger than or equal to a preset threshold value, the maximum available torque of the motor is obtained according to the wheel speed differences, and the safety pre-estimated torque is determined according to the wheel speed differences and the maximum available torque. When the wheel speed difference is larger than or equal to the preset threshold value, the current torque and the wheel speed difference at two ends are large, the differential mechanism is easily damaged, the safe estimated torque which can enable the differential mechanism to safely operate is calculated through the wheel speed difference, then the safe estimated torque is output, the motor is driven to reduce the torque to the safe estimated torque, the wheel speed difference at two ends is reduced, the differential mechanism is protected, the torque of the motor is detected and limited through the motor controller, the wheel speed difference is reduced, the differential mechanism can be effectively protected, the interaction process of the vehicle controller with respect to the torque can be reduced, and the whole vehicle calibration time and the test vehicle debugging time are reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive exercise.
Fig. 1 is a schematic flowchart of a control method according to an embodiment of the present application;
FIG. 2 is a schematic flow chart of determining a current torque as set forth in an embodiment of the present application;
FIG. 3 is a schematic flow chart of determining safe torque as set forth in an embodiment of the present application;
FIG. 4 is a graph of an external torque characteristic proposed by an embodiment of the present application;
FIG. 5 is a schematic flow chart of outputting a safety predicted torque according to an embodiment of the present application;
FIG. 6 is a block diagram of a control device according to an embodiment of the present application;
fig. 7 is a block diagram of an electronic device according to an embodiment of the present application.
Description of reference numerals: 5. a control device; 51. an acquisition module; 52. a determination module; 53. and executing the module.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
With the rapid development of new energy automobiles, driving motors with different powers and different rotating speed categories are widely applied, and an electric driving system is carried with a reduction gearbox for reducing speed and increasing torque. In order to reduce tire wear, downshift power and fuel consumption, enhance vehicle steering and braking capability, and be affected by cost, reduction gearboxes are generally equipped with differentials without differential locks. The differential gear box is limited by the capacity of the differential gear box, and when the difference value of the wheel speeds on the two sides is too large and the output torque of the motor is larger, the differential gear box can be damaged.
In the related art, for a reduction gearbox without a differential lock, the existing new energy automobile has the following processing modes aiming at differential protection:
1, no protection, purely depending on the capacity of the differential;
2, for the reduction gearbox with the gear-disengaging mechanism, emergency gear-disengaging is carried out when the bearing wheel speed difference and the bearing torque are reached according to the external characteristic curve of the differential mechanism;
and 3, the torque limitation of the whole vehicle controller on the motor torque is realized.
The vehicle control unit detects and controls a plurality of related parameters of the differential mechanism, and when the torque is limited by directly monitoring the torque through the vehicle control unit, the interaction process of the vehicle about the torque is easy to be complex, and further the method for protecting the differential mechanism is difficult to realize, the calibration and debugging time of the whole vehicle is long, the research and development efficiency is low, and the like.
In view of the above, referring to fig. 1, a first aspect of the embodiments of the present application provides a control method for a motor of an electric vehicle, based on a driving motor controller, the control method including:
s1, detecting the wheel speed difference at two ends of the differential, and acquiring the maximum available torque of the motor according to the wheel speed difference when the wheel speed difference is greater than or equal to a preset threshold value;
the method comprises the steps of monitoring the wheel speeds of two ends of a shaft through a motor controller, inputting the wheel speeds of the two ends into the motor controller, obtaining wheel speed differences of the two ends through calculation, determining the maximum available torque corresponding to the wheel speed differences according to an external torque characteristic curve, wherein the maximum available torque is measured by a laboratory, the maximum output torque of a motor, which can be borne by a differential mechanism under a certain wheel speed difference, is the maximum available torque of the motor, and the differential mechanism is easily damaged when the output torque of the motor exceeds the maximum available torque.
S2, determining a safe estimated torque according to the wheel speed difference and the maximum available torque;
the torque corresponding to the wheel speed difference preset threshold is a critical value of the torque which is easy to damage the differential mechanism under the current wheel speed difference, and the wheel speed difference threshold is set for different vehicles according to the performance of the differential mechanism and the working conditions of the vehicles.
When the wheel speed difference is larger than or equal to the preset threshold value, the wheel speed difference at two ends of the differential is too large, and the differential is easy to damage, so that the safe estimated torque for driving the differential to work safely is calculated through the maximum available torque and the wheel speed difference.
And S3, outputting the safety predicted torque to the vehicle controller of the vehicle controller so as to reduce the current torque of the motor to the safety predicted torque.
The safety pre-estimation torque is output to the vehicle control unit, the vehicle control unit outputs request information about the obtained safety pre-estimation torque to the motor controller, and the motor controller drives the motor to reduce the current torque of the motor to the safety pre-estimation torque, so that the wheel speed difference at two ends of the differential is reduced, and the differential is protected.
The method comprises the steps of obtaining wheel speeds at two ends of a vehicle differential in real time in the running process of a vehicle, obtaining wheel speed difference at the two ends, obtaining the maximum available torque of a motor according to the wheel speed difference when the wheel speed difference is larger than or equal to a preset threshold value, and determining the safe estimated torque according to the wheel speed difference and the maximum available torque. When the wheel speed difference is larger than or equal to the preset threshold value, the current torque and the wheel speed difference at two ends are large, the differential mechanism is easily damaged, the safe estimated torque which can enable the differential mechanism to safely operate is calculated through the wheel speed difference, then the safe estimated torque is output, the motor is driven to reduce the torque to the safe estimated torque, the wheel speed difference at two ends is reduced, the differential mechanism is protected, the torque of the motor is detected and limited through the motor controller, the wheel speed difference is reduced, the differential mechanism can be effectively protected, the interaction process of the vehicle controller with respect to the torque can be reduced, and the whole vehicle calibration time and the test vehicle debugging time are reduced.
Wherein, referring to fig. 2, determining the maximum available torque of the motor according to the wheel speed difference comprises:
s101, determining a wheel speed difference of two end wheel speeds according to the two end wheel speeds of the differential;
the wheel speeds of the two ends of the shaft are monitored through the motor controller, the wheel speeds of the two ends are input into the motor controller, the wheel speeds of the two ends are subtracted, and an absolute value of a numerical value is obtained and serves as a wheel speed difference.
And S102, determining the maximum available torque corresponding to the wheel speed difference in a preset torque outer characteristic curve.
In the present embodiment, the maximum available torque is T max The torque outer characteristic curve is a curve diagram corresponding to the wheel speed difference and the maximum torque which can be borne by the wheel speed difference, and the maximum bearing torques corresponding to different wheel speed differences are calibrated one by one through experiments to form a curve diagram, namely the torque outer characteristic curve of the wheel speed difference.
Referring to fig. 4, in one embodiment, the torque outer characteristic curve is shown in fig. 4, wherein the difference in rotational speed on the ordinate and on the first row of the lower map is the wheel speed difference in the present application, and the corresponding torque on the abscissa and on the second row of the lower map is the maximum available torque in the present application. The greater the wheel speed difference, the less the maximum available torque that the differential can withstand.
And substituting the wheel speed difference into the torque external characteristic curve after obtaining the wheel speed difference to obtain a torque threshold value corresponding to the wheel speed difference, namely the maximum available torque which can be borne by the differential mechanism at present.
Referring to FIG. 3, in some embodiments, determining a safe predicted torque based on the wheel speed differential and the maximum available torque includes:
s201, determining a torque limit coefficient and a time coefficient of a differential according to a wheel speed difference and a timer;
when calculating the safe estimated torque, the maximum available torque to be executed by the motor needs to be corrected according to the current wheel speed difference and the time when the wheel speed difference is greater than or equal to the preset threshold value, so that a target torque capable of reducing the current wheel speed difference when the torque of the motor is reduced is obtained, and the required target torque is the safe estimated torque.
Wherein, confirm torque limiting coefficient, time coefficient of the differential gear according to the difference of wheel speed, include:
and substituting the wheel speed difference into a torsion limiting coefficient chart to obtain a torsion limiting coefficient corresponding to the wheel speed difference.
The torque limiting factor is μ in this embodiment l Calculating and processing the torque external characteristic curve of the wheel speed difference by an interpolation method to obtain a torque limiting coefficient chart of the wheel speed difference and the torque limiting coefficient, substituting the wheel speed difference into the torque limiting coefficient chart to obtain the torque limiting coefficient mu corresponding to the current wheel speed difference l 。
Referring to table 1, in one embodiment, the torque limiting coefficient table is shown in table 1, wherein the rotational speed difference in the first row is the wheel speed difference in rpm, the second row is another unit Kp/h for wheel speed difference, and the third row is the torque limiting coefficient value corresponding to different wheel speed differences. The greater the wheel speed difference, the less the maximum available torque that the differential can withstand, and therefore the less the safety prediction torque that needs to be performed.
TABLE 1
Differential wheel speed/rpm ≤50 100 150 200 250 300 350 400 450 ≥500
Differential rotational speed/Kp/h ≤6.01 12.03 18.04 24.05 30.07 36.08 42.09 48.1 54.12 ≥60.13
Coefficient of torque limitation 1 0.965 0.912 0.842 0.754 0.649 0.526 0.386 0.228 0
And when the wheel speed difference is greater than or equal to a preset threshold value, timing is started through a timer until the safety pre-estimated torque is determined to obtain a time value, and the time value is substituted into a time coefficient chart to obtain a time coefficient corresponding to the time value.
The time coefficient is μ in this embodiment t When the wheel speed difference is greater than or equal to a preset threshold value, namely the wheel speed difference exceeds a safety range, in the case that the damage to the differential is larger as the running time of the differential is longer, the wheel speed difference is required to be reduced as soon as possible, so that the torque capable of reducing the current wheel speed difference when the torque of the motor is reduced is required to be dynamically corrected through the time length of the wheel speed difference exceeding the safety range, counting is started when the wheel speed difference exceeds the safety range, the time value of the wheel speed difference exceeding the safety range is obtained, and the time coefficient mu is obtained according to the interval of the time value in the time coefficient chart t 。
Referring to table 2, in an embodiment, the time coefficient table is shown in table 2, where the time in the first row is the time value of the present application when the wheel speed difference exceeds the safety range, and is measured in seconds, the time coefficient in the second row is the value of the time coefficient of the corresponding point of the interval where the time value is located, and the larger the time value is, the more the wheel speed difference needs to be reduced as soon as possible, so the smaller the safety predicted torque needs to be executed.
TABLE 2
Time value/s t≤0.5 0.5＜t≤1 1＜t≤2.5 2.5＜t≤5 5＜t≤7.5 t＞7.5
Time coefficient 1 0.8 0.5 0.2 0.05 0
S202, determining the safety predicted torque of the differential according to the maximum available torque, the torque limiting coefficient and the time coefficient.
Wherein, according to the maximum available torque, the torque limiting coefficient and the time coefficient, the safety estimated torque of the differential is determined, and the method comprises the following steps: and multiplying the maximum available torque, the torque limiting coefficient and the time coefficient to obtain the safety estimated torque of the differential.
The maximum available torque T to be obtained max Passing the torque limiting coefficient mu l And a time coefficient mu t And (3) correcting, namely:
T＝T max ·μ l ·μ t
thereby obtaining the safety estimated torque T.
Referring to fig. 5, in some embodiments, outputting the safety predicted torque to the vehicle controller unit to reduce the current torque of the motor to the full predicted torque includes:
s301, outputting a safety estimated torque to the vehicle control unit;
s302, receiving a safety pre-estimated torque request returned by the vehicle control unit aiming at the safety pre-estimated torque;
after the safety predicted torque is obtained, the motor controller cannot directly execute the safety predicted torque, so that the obtained safety predicted torque is transmitted to the vehicle control unit, and then a request instruction for executing the safety predicted torque is sent to the motor controller through the vehicle control unit.
And S303, responding to the safety predicted torque request, driving the motor to reduce the torque based on the safety predicted torque and output the torque to the safety predicted torque.
And after the motor controller obtains a request instruction of the vehicle control unit about the safe estimated torque, driving the motor to execute the safe estimated torque according to the request instruction.
Along with the time when the wheel speed difference is larger than or equal to the preset threshold value is continuously prolonged, the safety predicted torque is gradually reduced until the current torque is smaller than the maximum available torque, so that the motor is reduced from the current torque to the safety predicted torque, the wheel speed difference of the differential is reduced, and the differential is protected.
In some embodiments, after the motor controller reduces the output torque, the control method further comprises:
and S4, when the wheel speed difference is lower than a preset threshold value, outputting a preset torque to the vehicle controller so that the motor of the vehicle outputs the torque according to the preset torque, wherein the preset torque is a motor pre-execution torque which is not corrected according to the wheel speed difference.
After the current torque is reduced, the wheel speed difference of the differential mechanism is reduced, and the differential mechanism enters a safe state, so that the motor of the vehicle can perform torque according to the motor which is not corrected according to the wheel speed difference, and the vehicle can recover power.
Based on the same inventive concept, a second aspect of the embodiments of the present application provides a control device for a motor of an electric vehicle, and referring to fig. 6, the control device 5 includes:
the obtaining module 51 is configured to detect a wheel speed difference between two ends of the differential, and obtain a maximum available torque of the motor according to the wheel speed difference when the wheel speed difference is greater than or equal to a preset threshold;
in one embodiment, the acquisition module includes a motor controller for detecting a wheel speed at both ends of the differential and determining a wheel speed differential based on the wheel speeds at both ends.
A determination module 52, configured to determine a safety predicted torque according to the wheel speed difference and the maximum available torque;
and the execution module 53 is configured to output the safety predicted torque to the vehicle controller of the vehicle controller, so that the current torque of the motor is reduced to the safety predicted torque.
In some embodiments, the determination module 52 and the execution module 53 are integrated on a drive motor controller, such that the above-described method is performed by the motor controller.
The obtaining module 51 is further configured to perform the following steps:
determining the wheel speed difference of the wheel speeds of the two ends according to the wheel speeds of the two ends of the differential;
the maximum available torque corresponding to the wheel speed difference is determined in a preset torque outer characteristic curve.
The determination module 52 is further configured to perform the following steps:
determining a torque limiting coefficient and a time coefficient of the differential according to the wheel speed difference and the timer;
and determining the safety predicted torque of the differential according to the maximum available torque, the torque limiting coefficient and the time coefficient.
The determination module 52 is further configured to perform the following steps:
substituting the wheel speed difference into a torsion limiting coefficient chart to obtain a torsion limiting coefficient corresponding to the wheel speed difference;
and when the wheel speed difference is greater than or equal to a preset threshold value, timing is started until the safety pre-estimated torque is determined, a time value is obtained, and the time value is substituted into a time coefficient chart to obtain a time coefficient corresponding to the time value.
The determination module 52 is further configured to perform the following steps:
and multiplying the maximum available torque, the torque limiting coefficient and the time coefficient to obtain the safety estimated torque of the differential.
The execution module 53 is further configured to perform the following steps:
outputting a safety estimated torque to the vehicle control unit;
receiving a safety pre-estimated torque request returned by the vehicle control unit aiming at the safety pre-estimated torque;
and responding to the safety predicted torque request, and driving the motor to reduce the torque and output the torque to the safety predicted torque based on the safety predicted torque.
The execution module 53 is further configured to perform the following steps:
and when the wheel speed difference is lower than a preset threshold value, outputting a preset torque to the vehicle controller so that a motor of the vehicle outputs the torque according to the preset torque, wherein the preset torque is a motor pre-execution torque which is not corrected according to the wheel speed difference.
Based on the same inventive concept, an embodiment of the present application further provides an electronic device, and with reference to fig. 7, the electronic device includes:
a memory for storing a computer program;
a processor for executing a computer program stored on the memory to implement the control method described above.
Based on the same inventive concept, the embodiment of the application also provides a vehicle, which comprises the control device, and the control device is used for realizing the control method.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.
As will be appreciated by one of skill in the art, embodiments of the present application may be provided as a method, apparatus, or computer program product. Accordingly, embodiments of the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present application 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.
Embodiments of the present application are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the application. 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 terminal to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal, 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 terminal 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 terminal to cause a series of operational steps to be performed on the computer or other programmable terminal to produce a computer implemented process such that the instructions which execute on the computer or other programmable terminal provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present application have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the true scope of the embodiments of the application.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal 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 terminal. 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 terminal that comprises the element.
It should also be noted that, in this document, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the present application. Moreover, relational terms such as "first" and "second" are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions or neither should the relative importance be understood or implied. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal 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 terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or terminal equipment comprising the element.
The technical solutions provided by the present application are described in detail above, and the principles and embodiments of the present application are described herein by using specific examples, which are only used to help understanding the present application, and the content of the present description should not be construed as limiting the present application. While various modifications of the illustrative embodiments and applications will be apparent to those skilled in the art based upon this disclosure, it is not necessary or necessary to exhaustively enumerate all embodiments, and all obvious variations and modifications can be resorted to, falling within the scope of the disclosure.

Claims (10)

1. A control method of a motor of an electric vehicle, characterized by comprising:
detecting wheel speed difference at two ends of a differential, and acquiring the maximum available torque of the motor according to the wheel speed difference when the wheel speed difference is greater than or equal to a preset threshold value;
determining a safe estimated torque according to the wheel speed difference and the maximum available torque;
and outputting the safety predicted torque to a vehicle control unit so as to reduce the current torque of the motor to the safety predicted torque.
2. The control method of claim 1, wherein determining a maximum available torque of the electric machine based on the wheel speed differential comprises:
determining the wheel speed difference of the wheel speeds of the two ends according to the wheel speeds of the two ends of the differential;
determining the maximum available torque corresponding to the wheel speed difference in a preset torque outer characteristic curve.
3. The control method of claim 1, wherein determining a safe predicted torque based on the wheel speed differential and the maximum available torque comprises:
determining a torque limit coefficient and a time coefficient of the differential according to the wheel speed difference and a timer;
and determining the safe predicted torque of the differential according to the maximum available torque, the torque limiting coefficient and the time coefficient.
4. The control method of claim 3, wherein determining a torque limit coefficient and a time coefficient for the differential from the wheel speed differential comprises:
substituting the wheel speed difference into a torque limiting coefficient chart to obtain the torque limiting coefficient corresponding to the wheel speed difference;
and when the wheel speed difference is larger than or equal to a preset threshold value, timing is started until the safety pre-estimated torque is determined, a time value is obtained, and the time value is substituted into a time coefficient chart to obtain the time coefficient corresponding to the time value.
5. The control method of claim 3, wherein determining a safe predicted torque for the differential based on the maximum available torque, the torque limit factor, and the time factor comprises:
and multiplying the maximum available torque, the torque limiting coefficient and the time coefficient to obtain the safety estimated torque.
6. The control method according to claim 3, wherein outputting the safety pre-estimated torque to a vehicle control unit to reduce a current torque of the motor to the safety pre-estimated torque includes:
outputting the safety estimated torque to a vehicle controller;
receiving a safety pre-estimated torque request returned by the vehicle control unit aiming at the safety pre-estimated torque;
and responding to the safety predicted torque request, and driving a motor to output the safety predicted torque based on the safety predicted torque reduction torque.
7. The control method according to claim 1, wherein after the motor controller reduces the output torque, the control method further comprises:
and when the wheel speed difference is lower than a preset threshold value, outputting a preset torque to the vehicle controller so that a motor of the vehicle outputs the torque according to the preset torque, wherein the preset torque is a motor pre-execution torque which is not corrected according to the wheel speed difference.
8. A control device of a motor of an electric vehicle, characterized by comprising:
the acquisition module is used for detecting the wheel speed difference at the two ends of the differential mechanism, and acquiring the maximum available torque of the motor according to the wheel speed difference when the wheel speed difference is greater than or equal to a preset threshold value;
the determining module is used for determining a safety estimated torque according to the wheel speed difference and the maximum available torque;
and the execution module is used for outputting the safety predicted torque to the vehicle control unit so as to reduce the current torque of the motor to the safety predicted torque.
9. An electronic device, comprising:
a memory for storing a computer program;
a processor for executing a computer program stored on the memory to implement the control method of any one of claims 1-7.
10. A vehicle characterized by comprising the control apparatus of claim 8 for implementing the control method of any one of claims 1 to 7.
CN202110819569.0A 2021-07-20 2021-07-20 Control method and device for motor of electric automobile and vehicle Pending CN114954027A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110819569.0A CN114954027A (en) 2021-07-20 2021-07-20 Control method and device for motor of electric automobile and vehicle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110819569.0A CN114954027A (en) 2021-07-20 2021-07-20 Control method and device for motor of electric automobile and vehicle

Publications (1)

Publication Number Publication Date
CN114954027A true CN114954027A (en) 2022-08-30

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110819569.0A Pending CN114954027A (en) 2021-07-20 2021-07-20 Control method and device for motor of electric automobile and vehicle

Country Status (1)

Country Link
CN (1) CN114954027A (en)

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