CN107919827A - Electric automobile and control method and device of driving motor of electric automobile - Google Patents

Electric automobile and control method and device of driving motor of electric automobile Download PDF

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Publication number
CN107919827A
CN107919827A CN201711148690.5A CN201711148690A CN107919827A CN 107919827 A CN107919827 A CN 107919827A CN 201711148690 A CN201711148690 A CN 201711148690A CN 107919827 A CN107919827 A CN 107919827A
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China
Prior art keywords
driving motor
current
stator
axis
torque
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CN201711148690.5A
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Chinese (zh)
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CN107919827B (en
Inventor
曹永霞
刘立志
蒋荣勋
苏伟
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Beijing Electric Vehicle Co Ltd
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Beijing Electric Vehicle Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
    • H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
    • H02P25/022—Synchronous motors
    • H02P25/024—Synchronous motors controlled by supply frequency
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P2205/00—Indexing scheme relating to controlling arrangements characterised by the control loops
    • H02P2205/05—Torque loop, i.e. comparison of the motor torque with a torque reference
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P2207/00—Indexing scheme relating to controlling arrangements characterised by the type of motor
    • H02P2207/05—Synchronous machines, e.g. with permanent magnets or DC excitation
    • 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
    • Y02T10/64—Electric machine technologies in electromobility
    • 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)
  • Control Of Ac Motors In General (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The invention discloses an electric automobile and a control method and a control device of a driving motor of the electric automobile, wherein the method comprises the following steps: acquiring the rotating speed of a driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage of the driving motor; when the rotating speed of the driving motor is greater than the preset rotating speed, acquiring the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage; acquiring a torque difference value between the current output torque and a target torque; and controlling the driving motor according to the torque difference value. According to the method provided by the invention, the output torque of the driving motor can be conveniently and effectively acquired, and the driving motor is controlled according to the output torque, so that the safety of the electric automobile in the driving process can be improved.

Description

Electric automobile and control method and device of driving motor of electric automobile
Technical Field
The invention relates to the technical field of electric automobiles, in particular to a control method of a driving motor of an electric automobile, a non-transitory computer readable storage medium, a control device of the driving motor of the electric automobile and the electric automobile.
Background
The electric automobile driving motor and the controller can work under a severe environment, the running condition of the automobile is very complex, the phenomenon of out-of-control torque can occur to the electric automobile driving motor, although the probability of the phenomenon is low, once the phenomenon occurs, the electric automobile driving motor and the controller can cause great damage to people and the automobile, and particularly when the electric automobile runs at a high speed.
However, due to the limitations of cost and installation space, a torque sensor is generally not installed on an electric vehicle, so that the actual output torque of the motor cannot be detected in real time, and further, whether the torque of the motor is out of control cannot be judged, so that the safety of passengers cannot be guaranteed.
Disclosure of Invention
The present invention is directed to solving at least one of the technical problems in the art to some extent. Therefore, an object of the present invention is to provide a method for controlling a driving motor of an electric vehicle, which can conveniently and effectively obtain an output torque of the driving motor, and control the driving motor according to the output torque, so as to improve safety of the electric vehicle during driving.
A second object of the invention is to propose a non-transitory computer-readable storage medium.
The third purpose of the invention is to provide a control device of the driving motor of the electric automobile.
The fourth purpose of the invention is to provide an electric automobile.
In order to achieve the above object, a first embodiment of the present invention provides a method for controlling a driving motor of an electric vehicle, including the steps of: acquiring the rotating speed of a driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage of the driving motor; when the rotating speed of the driving motor is greater than a preset rotating speed, obtaining the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage; acquiring a torque difference value between the current output torque and a target torque; and controlling the driving motor according to the torque difference value.
According to the control method of the driving motor of the electric automobile, the rotating speed of the driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage of the driving motor are obtained, when the rotating speed of the driving motor is larger than the preset rotating speed, the current output torque of the driving motor is obtained according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage, the torque difference value between the current output torque and the target torque is obtained, and the driving motor is controlled according to the torque difference value. Therefore, the output torque of the driving motor can be conveniently and effectively acquired, and the driving motor is controlled according to the output torque, so that the safety of the electric automobile in the driving process can be improved.
In addition, the control method for the driving motor of the electric vehicle according to the above embodiment of the present invention may further have the following additional technical features:
in one embodiment of the present invention, obtaining the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the dc bus voltage includes: calculating the three-phase voltage of the driving motor according to the duty ratio of a switch tube control signal in the inverter, the voltage of the direct current and the dead time, the conduction time and the turn-off time of the switch tube control signal in the inverter; converting the three-phase voltage of the driving motor to obtain the stator voltage of the driving motor under a static rectangular coordinate system; converting the three-phase current of the driving motor to obtain the stator current of the driving motor under a static rectangular coordinate system; acquiring the resistance value of a stator phase winding in the driving motor according to the temperature of the driving motor; calculating the stator flux linkage of the driving motor according to the stator voltage under the static rectangular coordinate system of the driving motor, the stator current under the static rectangular coordinate system of the driving motor and the resistance value of a stator phase winding in the driving motor; and calculating the current output torque of the driving motor according to the stator flux linkage of the driving motor, the stator current of the driving motor under the static rectangular coordinate system and the pole pair number of the driving motor.
Specifically, the three-phase voltage of the driving motor is calculated according to the following formula:
wherein, V u 、V v 、V w Is the three-phase voltage, V, of the drive motor dc Is the DC bus voltage, D u 、D v 、D w Is the duty ratio of the control signal of the switch tube in the inverter, i u 、i v 、i w As three-phase current of the drive motor, T d 、T on 、T off The dead time, the conduction time and the turn-off time of the control signal of the switching tube in the inverter are respectively.
Further, the stator flux linkage of the drive motor is calculated according to the following formula:
therein, Ψ α 、Ψ β The alpha-axis and beta-axis components, u, of the stator flux linkage of the drive motor α 、u β Alpha-axis and beta-axis components, i, of the stator voltage of the drive motor, respectively α 、i β Are respectively the alpha-axis and beta-axis components, R, of the stator current of the drive motor s And the resistance value of the stator phase winding in the driving motor is obtained.
Further, the current output torque of the driving motor is calculated according to the following formula:
wherein, T e And p is the current output torque of the driving motor and is the pole pair number of the driving motor.
In one embodiment of the present invention, controlling the driving motor according to the torque difference value includes: judging whether the torque difference value is larger than a first threshold value or not; if the torque difference value is smaller than or equal to the first threshold value, maintaining the current state of the driving motor; if the torque difference value is larger than the first threshold value, further judging whether the torque difference value is smaller than a second threshold value, wherein the second threshold value is larger than the first threshold value; if the torque difference is smaller than the second threshold, reducing the direct-axis current and the quadrature-axis current of the driving motor by a first proportion; if the torque difference value is larger than or equal to the second threshold value, further judging whether the torque difference value is smaller than a third threshold value, wherein the third threshold value is larger than the second threshold value; if the torque difference is less than the third threshold, reducing the direct axis current and the quadrature axis current of the drive motor by a second proportion, wherein the second proportion is less than the first proportion; and if the torque difference value is larger than or equal to the third threshold value, controlling all upper bridge arms in the inverter to be closed and all lower bridge arms in the inverter to be opened, or controlling all lower bridge arms in the inverter to be closed and all upper bridge arms in the inverter to be opened.
In order to achieve the above object, a non-transitory computer readable storage medium is provided according to a second aspect of the present invention, wherein the computer program is stored on the non-transitory computer readable storage medium, and when the computer program is executed by a processor, the non-transitory computer readable storage medium implements the control method for the driving motor of the electric vehicle according to the first aspect of the present invention.
According to the non-transitory computer readable storage medium of the embodiment of the invention, the stored computer program is executed, so that the output torque of the driving motor can be conveniently and effectively acquired, and the driving motor is controlled according to the output torque, thereby improving the safety of the electric vehicle in the driving process.
In order to achieve the above object, a third embodiment of the present invention provides a control device for a driving motor of an electric vehicle, including: the device comprises a first acquisition module, a second acquisition module and a control module, wherein the first acquisition module is used for acquiring the rotating speed of a driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage of the driving motor; the second obtaining module is used for obtaining the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage when the rotating speed of the driving motor is greater than the preset rotating speed; the third obtaining module is used for obtaining a torque difference value between the current output torque and a target torque; and the control module is used for controlling the driving motor according to the torque difference value.
According to the control device of the driving motor of the electric automobile, the first obtaining module is used for obtaining the rotating speed of the driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage of the driving motor, the second obtaining module is used for obtaining the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage when the rotating speed of the driving motor is larger than the preset rotating speed, the third obtaining module is used for obtaining the torque difference value between the current output torque and the target torque, and the control module is used for controlling the driving motor according to the torque difference value. Therefore, the output torque of the driving motor can be conveniently and effectively acquired, and the driving motor is controlled according to the output torque, so that the safety of the electric automobile in the driving process can be improved.
In addition, the control device for the driving motor of the electric vehicle according to the above embodiment of the present invention may further have the following additional technical features:
in an embodiment of the present invention, the second obtaining module is specifically configured to: calculating the three-phase voltage of the driving motor according to the duty ratio of a switch tube control signal in an inverter, the voltage of the direct current and the dead time, the conduction time and the turn-off time of the switch tube control signal in the inverter; converting the three-phase voltage of the driving motor to obtain the stator voltage of the driving motor under a static rectangular coordinate system; converting the three-phase current of the driving motor to obtain the stator current of the driving motor under a static rectangular coordinate system; acquiring the resistance value of a stator phase winding in the driving motor according to the temperature of the driving motor; calculating a stator flux linkage of the driving motor according to the stator voltage under the static rectangular coordinate system of the driving motor, the stator current under the static rectangular coordinate system of the driving motor and the resistance value of a stator phase winding in the driving motor; and calculating the current output torque of the driving motor according to the stator flux linkage of the driving motor, the stator current of the driving motor under the static rectangular coordinate system and the pole pair number of the driving motor.
Specifically, the second obtaining module calculates the three-phase voltage of the driving motor according to the following formula:
wherein, V u 、V v 、V w Is the three-phase voltage, V, of the drive motor dc For the DC bus voltage, D u 、D v 、D w Is the duty ratio of the control signal of the switch tube in the inverter, i u 、i v 、i w As three-phase current of the drive motor, T d 、T on 、T off The dead time, the conduction time and the turn-off time of the switch tube control signal in the inverter are respectively.
Further, the second obtaining module calculates a stator flux linkage of the driving motor according to the following formula:
therein, Ψ α 、Ψ β The alpha-axis and beta-axis components, u, of the stator flux linkage of the drive motor α 、u β Alpha-axis and beta-axis components, i, of the stator voltage of the drive motor, respectively α 、i β Are respectively provided withIs the alpha-axis, beta-axis component, R, of the stator current of the drive motor s And the resistance value of the stator phase winding in the driving motor is obtained.
Further, the second obtaining module calculates a current output torque of the driving motor according to the following formula:
wherein, T e And p is the number of pole pairs of the driving motor, wherein the current output torque of the driving motor is the current output torque of the driving motor.
In an embodiment of the present invention, the control module is specifically configured to: judging whether the torque difference value is larger than a first threshold value or not; if the torque difference value is less than or equal to the first threshold value, maintaining the current state of the driving motor; if the torque difference value is larger than the first threshold value, further judging whether the torque difference value is smaller than a second threshold value, wherein the second threshold value is larger than the first threshold value; if the torque difference is smaller than the second threshold, reducing the direct-axis current and the quadrature-axis current of the driving motor by a first proportion; if the torque difference value is larger than or equal to the second threshold value, further judging whether the torque difference value is smaller than a third threshold value, wherein the third threshold value is larger than the second threshold value; if the torque difference is less than the third threshold, reducing the direct axis current and the quadrature axis current of the drive motor by a second proportion, wherein the second proportion is greater than the first proportion; and if the torque difference value is larger than or equal to the third threshold value, controlling all upper bridge arms in the inverter to be closed and all lower bridge arms in the inverter to be opened, or controlling all lower bridge arms in the inverter to be closed and all upper bridge arms in the inverter to be opened.
In order to achieve the above object, a fourth aspect of the present invention provides an electric vehicle.
The electric vehicle according to the embodiment of the present invention includes the control device for the driving motor of the electric vehicle according to the above embodiment of the present invention, and for the specific implementation, reference may be made to the above embodiment, and details are not repeated herein for avoiding redundancy.
According to the electric automobile provided by the embodiment of the invention, the output torque of the driving motor can be conveniently and effectively acquired, and the driving motor is controlled according to the output torque, so that the safety of the driving motor in the driving process can be improved.
Drawings
Fig. 1 is a flowchart of a control method of a driving motor of an electric vehicle according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an electric vehicle drive motor control system according to one embodiment of the present invention;
FIG. 3 is a schematic diagram of obtaining a current output torque of a drive motor according to one embodiment of the present invention;
FIG. 4 is a flowchart illustrating a method for controlling a driving motor of an electric vehicle according to an embodiment of the present invention;
fig. 5 is a block diagram schematically illustrating a control apparatus for a driving motor of an electric vehicle according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The following describes an electric vehicle and a control method and device of a drive motor thereof according to an embodiment of the present invention with reference to the accompanying drawings.
Fig. 1 is a flowchart of a control method of a driving motor of an electric vehicle according to an embodiment of the invention.
As shown in fig. 1, a method for controlling a driving motor of an electric vehicle according to an embodiment of the present invention includes the steps of:
s1, obtaining the rotating speed of a driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage of the driving motor.
In one embodiment of the invention, the drive motor may be a permanent magnet synchronous motor. As shown in fig. 2, a rotor angle θ of an IPMSM (Interior Permanent Magnet Synchronous Motor) can be obtained by performing position decoding on the IPMSM, and the rotation speed n of the drive Motor can be obtained by performing an operation such as integration on the rotor angle θ.
And S2, when the rotating speed of the driving motor is greater than the preset rotating speed, obtaining the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage.
The preset rotating speed can be calibrated according to actual conditions. When the rotating speed of the driving motor is greater than the preset rotating speed, namely the driving motor runs at a high speed, namely the electric automobile runs at a high speed, the current output torque of the driving motor can be obtained according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage.
In one embodiment of the present invention, the three-phase voltages of the driving motor may be calculated according to a duty ratio of the switching tube control signal in the inverter, a voltage of the direct current, and a dead time, a turn-on time, and a turn-off time of the switching tube control signal in the inverter.
The on-time of the switch tube control signal in the inverter may be a time for controlling the switch tube in the inverter to be on in one period, the off-time of the switch tube control signal in the inverter may be a time for controlling the switch tube in the inverter to be off in one period, the duty ratio of the switch tube control signal in the inverter may be a ratio of the on-time to the period of the switch tube control signal in the inverter in one period, and the dead time of the switch tube control signal in the inverter may be a time for the switch tube of the upper bridge arm and the switch tube of the corresponding lower bridge arm to be simultaneously off in one period. For example, the switching tubes in the inverter may be Insulated Gate Bipolar Transistors (IGBTs), and the switching tubes in the inverter may include a U-phase upper arm switching tube, a U-phase lower arm switching tube, a V-phase upper arm switching tube, a V-phase lower arm switching tube, a W-phase upper arm switching tube, and a W-phase lower arm switching tube. As shown in fig. 2, the switch tube control signal in the inverter may be a PWM (Pulse Width Modulation) signal output by a SVPWM (Space Vector Pulse Width Modulation) module, where the PWM _ UT signal may control the switch tube of the U-phase upper bridge arm to be turned on or off, the PWM _ UB signal may control the switch tube of the U-phase lower bridge arm to be turned on or off, the PWM _ VT signal may control the switch tube of the V-phase upper bridge arm to be turned on or off, the PWM _ VT signal may control the switch tube of the V-phase lower bridge arm to be turned on or off, the PWM _ WT signal may control the switch tube of the W-phase upper bridge arm to be turned on or off, and the PWM _ WT signal may control the switch tube of the W-phase lower bridge arm to be turned on or off. The on time of the corresponding switching tube controlled by the PWM signal in one period, that is, the on time of the switching tube control signal in one period, may be the on time of the switching tube control signal in the inverter, and the off time of the switching tube controlled by the PWM signal in one period, that is, the off time of the switching tube control signal in the inverter, may be the on time of the PWM signal in one period, that is, the off time of the switching tube control signal in the inverter.
As shown in fig. 3, the duty ratio D of the control signal is controlled by the switch tube in the inverter u 、D v 、D w The three-phase voltage V of the driving motor can be obtained by phase voltage calculation u 、V v 、V w . Specifically, the three-phase voltage of the driving motor may be calculated according to the following formula:
wherein, V u 、V v 、V w Three-phase voltage, V, for driving electric motors dc Is a DC bus voltage D u 、D v 、D w For duty cycle, i, of the control signal of the switching tube in the inverter u 、i v 、i w Three-phase current, T, for driving electric motors d 、T on 、T off The dead time, the conduction time and the turn-off time of the control signal of the switch tube in the inverter are respectively.
Further, the three-phase voltage of the driving motor can be converted to obtain the stator voltage of the driving motor under a static rectangular coordinate system. Specifically, as shown in fig. 3, a three-phase voltage V may be applied to the driving motor u 、V v 、V w Clark conversion is carried out to obtain alpha-axis and beta-axis components u of stator voltage of driving motor α 、u β . Thus, the alpha-axis component u and the beta-axis component u of the stator voltage of the driving motor can be obtained relatively accurately α 、u β 。
In other embodiments of the present invention, besides obtaining the stator voltage under the static rectangular coordinate system of the driving motor by the above-mentioned method, as shown in fig. 2, the specified value of the direct axis voltage of the driving motor can also be directly output by the PI controllerGiven value of sum-quadrature axis voltageThe direct-axis voltage set value of the drive motorGiven value of sum-quadrature axis voltageAfter Park transformation (the included angle between the direct axis and the quadrature axis can be a rotor angle theta obtained by decoding the position of the IPMSM), alpha-axis and beta-axis components u of the stator voltage of the driving motor can be obtained α 、u β 。
In one embodiment of the invention, the three-phase current of the driving motor can be converted to obtain the stator current of the driving motor under a static rectangular coordinate system. As shown in fig. 2, three-phase currents i to drive the motor can be applied u 、i v 、i w Clark conversion is carried out to obtain alpha-axis and beta-axis components i of stator current of driving motor α 、i β 。
In one embodiment of the present invention, the resistance Rs of the stator phase winding in the driving motor can be obtained according to the temperature T of the driving motor.
Specifically, the resistance Rs of the stator phase winding of the driving motor may vary with the temperature T of the driving motor, that is, there is a correspondence between the resistance Rs of the stator phase winding of the driving motor and the temperature T of the driving motor, that is, rs = f (T), and the correspondence may be stored in advance in the form of a table, and thus, as shown in fig. 3, the resistance Rs of the stator phase winding of the driving motor may be correspondingly obtained from the table according to the temperature T of the driving motor.
In one embodiment of the invention, the stator flux linkage of the driving motor can be calculated according to the stator voltage under the static rectangular coordinate system of the driving motor, the stator current under the static rectangular coordinate system of the driving motor and the resistance value of the stator phase winding in the driving motor.
As shown in fig. 3, the stator voltage of the driving motor is divided into α -axis and β -axis components u α 、u β Alpha-axis and beta-axis components i of stator current of driving motor α 、i β Resistance R of stator phase winding in driving motor s Performing flux linkage calculation to obtain stator flux linkage psi of the drive motor α 、Ψ β . Specifically, the stator flux linkage of the drive motor can be calculated by the following formula:
therein, Ψ α 、Ψ β Alpha-axis and beta-axis components, u, of the stator flux linkage of the drive motor, respectively α 、u β Alpha-axis and beta-axis components, i, of the stator voltage of the drive motor, respectively α 、i β Alpha-axis and beta-axis components, R, respectively, of the stator current of the drive motor s Is the resistance of the stator phase winding in the driving motor.
Further, the current output torque of the driving motor can be calculated according to the stator flux linkage of the driving motor, the stator current of the driving motor under the static rectangular coordinate system and the pole pair number of the driving motor.
As shown in fig. 3, the stator current of the drive motor in the above embodiment passes through the α -axis,Component of beta axis i α 、i β The alpha-axis and beta-axis components Ψ of the stator flux linkage of the drive motor α 、Ψ β And calculating the output torque of the pole pair number p of the driving motor to obtain the current output torque T of the driving motor e Specifically, the current output torque of the drive motor may be calculated according to the following formula:
wherein, T e P is the number of pole pairs of the drive motor for the current output torque of the drive motor.
And S3, acquiring a torque difference value between the current output torque and the target torque. Wherein, the target torque can be the rated torque of the driving motor of the electric automobile.
As shown in FIG. 3, the current output torque T may be adjusted e And target torque T cmd The torque deviation determination may be made, specifically, by calculating the current output torque T e Absolute value of (d) and target torque T cmd Obtaining the current output torque T by the difference of the absolute values of e And target torque T cmd Difference in torque Δ T between e I.e. Delta T e ＝|T e |-|T cmd |。
And S4, controlling the driving motor according to the torque difference value.
In one embodiment of the invention, the torque difference Δ T may be determined e Is greater than the first threshold Te1. If the torque difference Δ T e If the current output torque is smaller than or equal to the first threshold Te1, the current state of the driving motor is maintained, that is, the deviation between the current output torque of the driving motor and the target torque is small, or the absolute value of the current output torque of the driving motor is smaller than the absolute value of the target torque, and at this time, the driving motor operates normally, and the current state of the driving motor can be maintained.
If the torque difference Δ T e If the torque difference is larger than the first threshold Te1, the torque difference Delta T is further judged e Whether it is less than a second threshold Te2, where the second threshold Te2 is greater than the first threshold Te1.
If the torque difference Δ T e Less than the second threshold Te2, the direct-axis current and quadrature-axis current of the drive motor are reduced by the first proportion. If the torque difference Δ T e If the torque difference is larger than or equal to the second threshold Te2, the torque difference Delta T is further judged e Whether it is less than a third threshold Te3, where the third threshold Te3 is greater than the second threshold Te2.
If the torque difference Δ T e And if the second threshold Te3 is smaller than the third threshold Te, the direct-axis current and the quadrature-axis current of the driving motor are reduced by a second proportion.
Wherein, the second ratio is greater than the first ratio, that is, when the torque difference between the current output torque and the target torque of the driving motor is small, the direct-axis current and the quadrature-axis current of the driving motor can be reduced by a small margin, so that the output torque of the driving motor can be reduced by a small margin; when the torque difference between the current output torque and the target torque of the driving motor is large, the direct-axis current and the quadrature-axis current of the driving motor can be reduced by a large margin, so that the output torque of the driving motor can be reduced by a large margin.
Specifically, as shown in fig. 2, the limiting coefficients Kid _ limit and Kiq _ limit of the respective direct current and quadrature current may be output to the current distribution module by the control device to limit the direct current and quadrature current of the driving motor. For example, when the torque difference Δ T e When the first threshold Te1 is larger than the second threshold Te2, the first ratio may be 1/2, that is, the control module may output the limiting coefficients Kid _ limit and Kid _ limit, both of which have a magnitude of 1/2, to the current distribution module, so that the direct-axis current and the quadrature-axis current of the driving motor are 1/2 of the direct-axis current and the quadrature-axis current when the characteristics other than the driving motor are output. When the torque difference Δ T e When the second threshold Te2 is greater than or equal to the third threshold Te3 and less than the third threshold Te2, the second ratio may be 2/3, that is, the limiting coefficients Kid _ limit and Kiq _ limit, both of which have a magnitude of 1/3, may be output to the current distribution module through the control module, so that the direct-axis current and the quadrature-axis current of the driving motor are 1/3 of the direct-axis current and the quadrature-axis current when the characteristics other than the driving motor are output.
If the torque difference Δ T e And if the current is more than or equal to the third threshold Te3, controlling the upper bridge arm in the inverter to be completely closed or completely opened, or controlling the lower bridge arm in the inverter to be completely closed or completely opened, namely controlling the electric automobile to be safely stopped. Specifically, as shown in FIG. 2, when the torque difference Δ T is greater e When the current is more than or equal to the third threshold Te3, the control device can output a related instruction (ASC _ cmd is set to be 1) to the SVPWM module so that the SVPWM module outputs a PWM signal, and correspondingly, the upper bridge arm and the lower bridge arm in the inverter can be controlled to be completely closed and completely disconnected, or the lower bridge arm and the upper bridge arm in the inverter can be controlled to be completely closed and completely disconnected, so that the IPMSM is controlled to stop running, and the electric automobile is controlled to be safely stopped.
Therefore, when the current output torque of the driving motor deviates from the target torque, the driving motor can be effectively controlled according to the deviation, and the driving safety of passengers is ensured.
According to the control method of the driving motor of the electric automobile, the rotating speed of the driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage of the driving motor are obtained, when the rotating speed of the driving motor is larger than the preset rotating speed, the current output torque of the driving motor is obtained according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage, the torque difference value between the current output torque and the target torque is obtained, and the driving motor is controlled according to the torque difference value. Therefore, the output torque of the driving motor can be conveniently and effectively acquired, and the driving motor is controlled according to the output torque, so that the safety of the electric automobile in the driving process can be improved.
In an embodiment of the present invention, as shown in fig. 4, a method for controlling a driving motor of an electric vehicle according to an embodiment of the present invention includes the following steps:
s201, obtaining the rotating speed n of the driving motor and the three-phase current i of the driving motor u 、i v 、i w The temperature T of the driving motor and the direct current bus voltage Vdc of the driving motor.
S202, judging whether n > n1 exists or not. If yes, step S203, step S205, step S206 may be performed, respectively; if not, step S202 continues. And when n is greater than n1, the driving motor runs at a high speed, namely the electric automobile runs at a high speed.
S203, according to the duty ratio D of the control signal of the switch tube in the inverter u 、D v 、D w Voltage V of direct current dc And the dead time T of the control signal of the switch tube in the inverter d On-time T on And off time T off And calculating the three-phase voltage of the driving motor.
Specifically, the three-phase voltage of the driving motor may be calculated according to the following formula:
wherein, V u 、V v 、V w Three-phase voltage, V, for driving electric motors dc Is a DC bus voltage, D u 、D v 、D w For duty cycle, i, of switching tube control signals in inverters u 、i v 、i w Three-phase current, T, for driving electric motors d 、T on 、T off The dead time, the conduction time and the turn-off time of the control signal of the switch tube in the inverter are respectively.
And S204, converting the three-phase voltage of the driving motor to obtain the stator voltage of the driving motor under the static rectangular coordinate system. Wherein, clark conversion can be carried out on the three-phase voltage of the driving motor to obtain the alpha-axis and beta-axis components, namely u, of the stator voltage of the driving motor α 、u β 。
And S205, converting the three-phase current of the driving motor to obtain the stator current of the driving motor under the static rectangular coordinate system. Wherein, clark conversion can be carried out on the three-phase current of the driving motor to obtain the alpha-axis and beta-axis components, i.e. i, of the stator current of the driving motor α 、i β 。
And S206, acquiring the resistance Rs of the stator phase winding in the driving motor according to the temperature T of the driving motor.
And S207, calculating the stator flux linkage of the driving motor according to the stator voltage under the static rectangular coordinate system of the driving motor, the stator current under the static rectangular coordinate system of the driving motor and the resistance value of the stator phase winding in the driving motor. That is, the α -axis and β -axis components, i.e., u, of the stator voltage of the driving motor acquired in step S204 may be used α 、u β The α -axis and β -axis components of the stator current of the drive motor, i.e., i, obtained in step S205 α 、i β And calculating the stator flux linkage of the driving motor from the resistance value of the stator phase winding in the driving motor acquired in step S206.
Specifically, the stator flux linkage of the drive motor can be calculated by the following formula:
therein, Ψ α 、Ψ β Alpha-axis and beta-axis components, u, of the stator flux linkage of the drive motor, respectively α 、u β Alpha-axis and beta-axis components, i, of the stator voltage of the drive motor, respectively α 、i β Alpha-axis and beta-axis components, R, of the stator current of the drive motor, respectively s Is the resistance of the stator phase winding in the driving motor.
And S208, calculating the current output torque of the driving motor according to the stator flux linkage of the driving motor, the stator current of the driving motor under the static rectangular coordinate system and the pole pair number of the driving motor.
Specifically, based on the α -axis and β -axis components of the stator flux linkage of the drive motor, i.e., Ψ, obtained in step S207 α 、Ψ β The α -axis and β -axis components of the stator current of the drive motor, i.e., i, obtained in step S205 α 、i β And calculating the current output torque of the driving motor according to the following formula:
wherein, T e P is the number of pole pairs of the drive motor for the current output torque of the drive motor.
S209, calculate the value of Δ Te = | Te | Tcmd |.
S210, judging whether delta Te < Te1 exists or not. If yes, go to step S211; if not, step S212 is executed.
S211, the current state of the driving motor is maintained.
S212, whether delta Te < Te2 exists is judged. If so, go to step S213; if not, step S214 is performed.
S213, reducing the direct-axis current and the quadrature-axis current of the driving motor to 1/2 of the direct-axis current and the quadrature-axis current when the characteristics other than the driving motor are output.
And S214, judging whether delta Te < Te3 exists or not. If so, go to step S215; if not, step S216 is performed.
S215, reducing the direct-axis current and the quadrature-axis current of the driving motor to be 1/3 of the direct-axis current and the quadrature-axis current when the characteristics except the driving motor are output.
And S216, controlling all upper bridge arms in the inverter to be closed and all lower bridge arms in the inverter to be opened, or controlling all lower bridge arms in the inverter to be closed and all upper bridge arms in the inverter to be opened.
It should be noted that after step S211, step S213, step S215, or step S216 is completed, step S201 may be continuously executed to obtain the output torque of the driving motor in real time, and when the current output torque of the driving motor deviates from the target torque, the driving motor can be effectively controlled according to the magnitude of the deviation.
The invention also provides a non-transitory computer readable storage medium corresponding to the above embodiment.
A non-transitory computer-readable storage medium of an embodiment of the present invention stores a computer program, where when the program is executed by a processor, the method for controlling a driving motor of an electric vehicle according to the embodiment of the present invention may be implemented.
According to the non-transitory computer readable storage medium of the embodiment of the invention, the stored computer program is executed, so that the output torque of the driving motor can be conveniently and effectively acquired, and the driving motor is controlled according to the output torque, thereby improving the safety of the electric vehicle in the driving process.
The invention further provides a control device of the driving motor of the electric automobile, which corresponds to the embodiment.
As shown in fig. 5, the control apparatus for a driving motor of an electric vehicle according to an embodiment of the present invention may include a first obtaining module 100, a second obtaining module 200, a third obtaining module 300, and a control module 400.
The first obtaining module 100 is configured to obtain a rotation speed of the driving motor, a three-phase current of the driving motor, a temperature of the driving motor, and a dc bus voltage of the driving motor; the second obtaining module 200 is configured to obtain a current output torque of the driving motor according to a three-phase current of the driving motor, a temperature of the driving motor, and a dc bus voltage when a rotation speed of the driving motor is greater than a preset rotation speed; the third obtaining module 300 is configured to obtain a torque difference between the current output torque and the target torque; the control module 400 is configured to control the drive motor based on the torque difference.
In one embodiment of the invention, the drive motor may be a permanent magnet synchronous motor. As shown in fig. 2, the rotor angle θ of the driving motor can be obtained by position decoding of the IPMSM, and the rotation speed n of the driving motor can be obtained by integrating the rotor angle θ and the like.
The preset rotating speed can be calibrated according to actual conditions. When the rotation speed of the driving motor is greater than the preset rotation speed, that is, the driving motor runs at a high speed, that is, the electric vehicle runs at a high speed, the second obtaining module 200 may obtain the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor, and the dc bus voltage.
In an embodiment of the invention, the second obtaining module 200 may calculate the three-phase voltages of the driving motor according to a duty ratio of the switch tube control signal in the inverter, a voltage of the direct current, and a dead time, a turn-on time, and a turn-off time of the switch tube control signal in the inverter.
The on-time of the switch tube control signal in the inverter may be the on-time of the switch tube in the inverter controlled in one period, the off-time of the switch tube control signal in the inverter may be the off-time of the switch tube in the inverter controlled in one period, the duty ratio of the switch tube control signal in the inverter may be the ratio of the on-time to the total time of the switch tube control signal in the inverter controlled in one period, and the dead time of the switch tube control signal in the inverter may be the time of the switch tube of the upper arm and the switch tube of the corresponding lower arm being turned off simultaneously in one period. For example, as shown in fig. 2, the switching tubes in the inverter may be IGBTs, and the switching tubes in the inverter may include a U-phase upper bridge arm switching tube, a U-phase lower bridge arm switching tube, a V-phase upper bridge arm switching tube, a V-phase lower bridge arm switching tube, a W-phase upper bridge arm switching tube, and a W-phase lower bridge arm switching tube, and the switching tube control signal in the inverter may be a PWM signal output by the SVPWM module, where the PWM _ UT signal may control the U-phase upper bridge arm switching tube to be turned on or off, the PWM _ UB signal may control the U-phase lower bridge arm switching tube to be turned on or off, the PWM _ VT signal may control the V-phase upper bridge arm switching tube to be turned on or off, the PWM _ WT signal may control the W-phase upper bridge arm switching tube to be turned on or off, and the PWM _ WT signal may control the W-phase lower bridge arm switching tube to be turned on or off. The PWM signal in one cycle controls the on-time of the corresponding switching tube, that is, the time when the PWM signal in one cycle is a high level signal, may be the on-time of the switching tube control signal in the inverter, and the time when the PWM signal in one cycle controls the off-time of the corresponding switching tube, that is, the time when the PWM signal in one cycle is a low level signal, may be the off-time of the switching tube control signal in the inverter.
As shown in FIG. 3, the second obtaining module 200 obtains the duty ratio D of the control signal of the switch tube in the inverter through the comparison u 、D v 、D w The three-phase voltage V of the driving motor can be obtained by carrying out phase voltage calculation u 、V v 、V w . Specifically, the second obtaining module 200 may calculate the three-phase voltages of the driving motor according to the following formulas:
wherein, V u 、V v 、V w Three-phase voltage, V, for driving electric motors dc Is a DC bus voltage D u 、D v 、D w For duty cycle, i, of switching tube control signals in inverters u 、i v 、i w Three-phase current, T, for driving electric motors d 、T on 、T off The dead time, the conduction time and the turn-off time of the control signal of the switching tube in the inverter are respectively.
Further, the second obtaining module 200 may convert the three-phase voltage of the driving motor to obtain the stator voltage of the driving motor in the stationary rectangular coordinate system. Specifically, as shown in fig. 3, the second obtaining module 200 may obtain three-phase voltages V of the driving motor u 、V v 、V w Clark conversion is performed to obtain alpha-axis and beta-axis components u of stator voltage of drive motor α 、u β . Thus, the alpha-axis component u and the beta-axis component u of the stator voltage of the driving motor can be obtained relatively accurately α 、u β 。
In other embodiments of the present invention, besides obtaining the stator voltage under the static rectangular coordinate system of the driving motor by the above-mentioned method, as shown in fig. 2, the specified value of the direct axis voltage of the driving motor can also be directly output by the PI controllerGiven value of sum-quadrature axis voltageThe direct-axis voltage set value of the drive motorSum-quadrature voltage set pointThrough Park transformation (straight)The included angle between the axis and the intersecting axis can be a rotor angle theta) obtained by decoding the position of the IPMSM, and then the alpha-axis component u and the beta-axis component u of the stator voltage of the driving motor can be obtained α 、u β 。
In an embodiment of the present invention, the second obtaining module 200 may convert the three-phase current of the driving motor to obtain the stator current of the driving motor in the stationary rectangular coordinate system. As shown in fig. 2, the second obtaining module 200 may perform Clark transformation on the three-phase current of the driving motor to obtain α -axis and β -axis components i of the stator current of the driving motor α 、i β 。
In an embodiment of the invention, the second obtaining module 200 may obtain the resistance Rs of the stator phase winding in the driving motor according to the temperature T of the driving motor.
Specifically, the resistance Rs of the stator phase winding of the driving motor may vary with the temperature T of the driving motor, that is, there is a corresponding relationship between the resistance Rs of the stator phase winding of the driving motor and the temperature T of the driving motor, that is, rs = f (T), and the corresponding relationship may be stored in advance in a form of a table, so that, as shown in fig. 3, the second obtaining module 200 may correspondingly obtain the resistance Rs of the stator phase winding of the driving motor from the table according to the temperature of the driving motor.
In an embodiment of the invention, the second obtaining module 200 may calculate the stator flux linkage of the driving motor according to the stator voltage of the driving motor in the stationary rectangular coordinate system, the stator current of the driving motor in the stationary rectangular coordinate system, and the resistance value of the stator phase winding in the driving motor.
As shown in fig. 3, the second obtaining module 200 obtains the stator voltage of the driving motor by comparing the α -axis component u and the β -axis component u α 、u β Alpha-axis and beta-axis components i of stator current of drive motor α 、i β Resistance R of stator phase winding in driving motor s Performing flux linkage calculation to obtain stator flux linkage psi of the driving motor α 、Ψ β . Specifically, the second obtaining module 200 may calculate the stator flux linkage of the driving motor by the following formula:
therein, Ψ α 、Ψ β Alpha-axis and beta-axis components, u, of the stator flux linkage of the drive motor, respectively α 、u β Alpha-axis and beta-axis components, i, of the stator voltage of the drive motor, respectively α 、i β Alpha-axis and beta-axis components, R, respectively, of the stator current of the drive motor s Is the resistance of the stator phase winding in the driving motor.
Further, the second obtaining module 200 may calculate the current output torque of the driving motor according to the stator flux linkage, the stator current of the driving motor, and the pole pair number of the driving motor in the static rectangular coordinate system of the driving motor.
As shown in fig. 3, the second obtaining module 200 obtains the α -axis component and the β -axis component i of the stator current of the driving motor in the above embodiment α 、i β The alpha-axis and beta-axis components psi of the stator flux linkage of the drive motor α 、Ψ β And calculating the output torque of the pole pair number p of the driving motor to obtain the current output torque T of the driving motor e Specifically, the current output torque of the drive motor may be calculated according to the following formula:
wherein, T e P is the number of pole pairs of the drive motor for the current output torque of the drive motor.
In one embodiment of the present invention, as shown in FIG. 3, the third obtaining module 300 may obtain the current output torque T e And target torque T cmd The torque deviation determination may be made, specifically, the third obtaining module 300 may determine the current output torque T by calculating the current output torque T e Absolute value of (d) and target torque T cmd Obtaining the current output torque T by the difference of the absolute values of e And target torque T cmd Torque difference Δ T therebetween e I.e. Delta T e ＝|T e |-|T cmd L. the method is used for the preparation of the medicament. Wherein the target torque T cmd Can be the rated torque of the driving motor of the electric automobile.
In one embodiment of the invention, the control module 400 may determine the torque difference Δ T e Is greater than the first threshold Te1.
If the torque difference Δ T e If the current output torque is smaller than or equal to the first threshold Te1, the current state of the driving motor is maintained, that is, the deviation between the current output torque of the driving motor and the target torque is small, or the absolute value of the current output torque of the driving motor is smaller than the absolute value of the target torque, and at this time, the driving motor operates normally, and the current state of the driving motor can be maintained.
If the torque difference Δ T e If the torque difference is larger than the first threshold Te1, the torque difference delta T is further judged e Is less than a second threshold Te2, wherein the second threshold Te2 is greater than the first threshold Te1.
If the torque difference Δ T e When the second threshold Te2 is smaller, the direct-axis current and the quadrature-axis current of the driving motor are reduced by a first ratio. If the torque difference Δ T e If the torque difference is larger than or equal to the second threshold Te2, the torque difference Delta T is further judged e Whether it is less than a third threshold Te3, where the third threshold Te3 is greater than the second threshold Te2.
If the torque difference Δ T e If the second threshold value Te3 is smaller, the direct-axis current and the quadrature-axis current of the drive motor are reduced by a second ratio.
When the torque difference between the current output torque of the driving motor and the target torque is smaller, the direct-axis current and the quadrature-axis current of the driving motor can be reduced by smaller amplitude, so that the output torque of the driving motor can be reduced by smaller amplitude; when the torque difference between the current output torque and the target torque of the driving motor is large, the direct-axis current and the quadrature-axis current of the driving motor can be reduced by a large margin, so that the output torque of the driving motor can be reduced by a large margin.
Specifically, as shown in fig. 2, the control device (including the first acquiring module 100, the second acquiring module 200, the third acquiring module 300 and the control module 400) may output corresponding direct-axis current and alternating-axis currentAnd limiting coefficients Kid _ limit and Kiq _ limit of the shaft current are sent to the current distribution module to limit the direct shaft current and the quadrature shaft current of the driving motor. For example, when the torque difference Δ T e When the first threshold Te1 is larger than the second threshold Te2, the first ratio may be 1/2, that is, the control module may output the limiting coefficients Kid _ limit and Kid _ limit, both of which have a magnitude of 1/2, to the current distribution module, so that the direct-axis current and the quadrature-axis current of the driving motor are 1/2 of the direct-axis current and the quadrature-axis current when the characteristics other than the driving motor are output. When the torque difference Δ T e When the current is greater than or equal to the second threshold Te2 and less than the third threshold Te3, the second ratio may be 2/3, that is, the control module may output the limiting coefficients Kid _ limit and Kiq _ limit, both of which are 1/3, to the current distribution module, respectively, so that the direct-axis current and the quadrature-axis current of the driving motor are 1/3 of the direct-axis current and the quadrature-axis current when the characteristics other than the driving motor are output.
If the torque difference Δ T e And if the current is more than or equal to the third threshold Te3, controlling the upper bridge arm in the inverter to be completely closed or completely opened, or controlling the lower bridge arm in the inverter to be completely closed or completely opened, namely controlling the electric automobile to be safely stopped. Specifically, as shown in FIG. 2, when the torque difference Δ T is greater than the threshold value e When the current is more than or equal to the third threshold Te3, the control device can output a related instruction (ASC _ cmd is set to be 1) to the SVPWM module so that the SVPWM module outputs a PWM signal, and correspondingly, all upper bridge arms in the inverter can be controlled to be closed and all lower bridge arms in the inverter can be controlled to be opened, or all lower bridge arms in the inverter can be controlled to be closed and all upper bridge arms in the inverter can be controlled to control the IPMSM to stop running, so that the electric automobile can be controlled to be safely stopped.
Therefore, when the current output torque of the driving motor deviates from the target torque, the driving motor can be effectively controlled according to the deviation, and the driving safety of passengers is ensured.
According to the control device of the driving motor of the electric automobile, the first obtaining module is used for obtaining the rotating speed of the driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage of the driving motor, the second obtaining module is used for obtaining the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage when the rotating speed of the driving motor is larger than the preset rotating speed, the third obtaining module is used for obtaining the torque difference value between the current output torque and the target torque, and the control module is used for controlling the driving motor according to the torque difference value. Therefore, the output torque of the driving motor can be conveniently and effectively acquired, and the driving motor is controlled according to the output torque, so that the safety of the electric automobile in the driving process can be improved.
Corresponding to the embodiment, the invention further provides an electric automobile.
The electric vehicle according to the embodiment of the present invention includes the control device for the driving motor of the electric vehicle according to the above embodiment of the present invention, and for the specific implementation, reference may be made to the above embodiment, and details are not repeated herein for avoiding redundancy.
According to the electric automobile provided by the embodiment of the invention, the output torque of the driving motor can be conveniently and effectively acquired, and the driving motor can be effectively controlled according to the output torque, so that the safety of the driving motor in the driving process can be improved.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the present invention, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being permanently connected, detachably connected, or integral; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.
In the present invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the second feature or the first and second features may be indirectly contacting each other through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (14)

1. A control method of a driving motor of an electric automobile is characterized by comprising the following steps:
acquiring the rotating speed of a driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct current bus voltage of the driving motor;
when the rotating speed of the driving motor is greater than a preset rotating speed, acquiring the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage;
acquiring a torque difference value between the current output torque and a target torque;
and controlling the driving motor according to the torque difference value.
2. The method for controlling the driving motor of the electric vehicle according to claim 1, wherein obtaining the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the dc bus voltage comprises:
calculating the three-phase voltage of the driving motor according to the duty ratio of a switch tube control signal in the inverter, the voltage of the direct current and the dead time, the conduction time and the turn-off time of the switch tube control signal in the inverter;
converting the three-phase voltage of the driving motor to obtain the stator voltage of the driving motor under a static rectangular coordinate system;
converting the three-phase current of the driving motor to obtain the stator current of the driving motor under a static rectangular coordinate system;
acquiring the resistance value of a stator phase winding in the driving motor according to the temperature of the driving motor;
calculating a stator flux linkage of the driving motor according to the stator voltage under the static rectangular coordinate system of the driving motor, the stator current under the static rectangular coordinate system of the driving motor and the resistance value of a stator phase winding in the driving motor;
and calculating the current output torque of the driving motor according to the stator flux linkage of the driving motor, the stator current under the static rectangular coordinate system of the driving motor and the pole pair number of the driving motor.
3. The control method of the driving motor of the electric vehicle according to claim 2, wherein the three-phase voltage of the driving motor is calculated according to the following formula:
wherein, V u 、V v 、V w Is the three-phase voltage, V, of the drive motor dc For the DC bus voltage, D u 、D v 、D w Is the duty ratio of the control signal of the switch tube in the inverter, i u 、i v 、i w Is a three-phase current of the drive motor, T d 、T on 、T off The dead time, the conduction time and the turn-off time of the control signal of the switching tube in the inverter are respectively.
4. The control method of the electric vehicle driving motor according to claim 3, wherein the stator flux linkage of the driving motor is calculated according to the following formula:
therein, Ψ α 、Ψ β Are respectively shown asThe alpha-axis and beta-axis components, u, of the stator flux linkage of the drive motor α 、u β Alpha-axis and beta-axis components, i, of the stator voltage of the drive motor, respectively α 、i β Are respectively the alpha-axis and beta-axis components, R, of the stator current of the drive motor s And the resistance value of the stator phase winding in the driving motor is obtained.
5. The control method of the electric vehicle driving motor according to claim 4, wherein the current output torque of the driving motor is calculated according to the following formula:
wherein, T e And p is the current output torque of the driving motor and is the pole pair number of the driving motor.
6. The method for controlling the driving motor of the electric vehicle according to claim 5, wherein controlling the driving motor based on the torque difference value includes:
judging whether the torque difference value is larger than a first threshold value or not;
if the torque difference value is smaller than or equal to the first threshold value, maintaining the current state of the driving motor;
if the torque difference value is larger than the first threshold value, further judging whether the torque difference value is smaller than a second threshold value, wherein the second threshold value is larger than the first threshold value;
if the torque difference value is smaller than the second threshold value, reducing the direct-axis current and the quadrature-axis current of the driving motor by a first proportion;
if the torque difference value is larger than or equal to the second threshold value, further judging whether the torque difference value is smaller than a third threshold value, wherein the third threshold value is larger than the second threshold value;
if the torque difference is less than the third threshold, reducing the direct axis current and the quadrature axis current of the drive motor by a second proportion, wherein the second proportion is greater than the first proportion;
and if the torque difference value is larger than or equal to the third threshold value, controlling all upper bridge arms in the inverter to be closed and all lower bridge arms in the inverter to be opened, or controlling all lower bridge arms in the inverter to be closed and all upper bridge arms in the inverter to be opened.
7. A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that the program, when executed by a processor, implements the control method of the electric vehicle drive motor according to any one of claims 1 to 6.
8. A control device of a drive motor of an electric vehicle, characterized by comprising:
the device comprises a first acquisition module, a second acquisition module and a control module, wherein the first acquisition module is used for acquiring the rotating speed of a driving motor, the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage of the driving motor;
the second obtaining module is used for obtaining the current output torque of the driving motor according to the three-phase current of the driving motor, the temperature of the driving motor and the direct-current bus voltage when the rotating speed of the driving motor is greater than the preset rotating speed;
the third acquisition module is used for acquiring a torque difference value between the current output torque and a target torque;
and the control module is used for controlling the driving motor according to the torque difference value.
9. The control device of the electric vehicle driving motor according to claim 8, wherein the second obtaining module is specifically configured to:
calculating the three-phase voltage of the driving motor according to the duty ratio of a switch tube control signal in an inverter, the voltage of the direct current and the dead time, the conduction time and the turn-off time of the switch tube control signal in the inverter;
converting the three-phase voltage of the driving motor to obtain the stator voltage of the driving motor under a static rectangular coordinate system;
converting the three-phase current of the driving motor to obtain the stator current of the driving motor under a static rectangular coordinate system;
acquiring the resistance value of a stator phase winding in the driving motor according to the temperature of the driving motor;
calculating the stator flux linkage of the driving motor according to the stator voltage under the static rectangular coordinate system of the driving motor, the stator current under the static rectangular coordinate system of the driving motor and the resistance value of a stator phase winding in the driving motor;
and calculating the current output torque of the driving motor according to the stator flux linkage of the driving motor, the stator current of the driving motor under the static rectangular coordinate system and the pole pair number of the driving motor.
10. The control device of the electric vehicle driving motor according to claim 9, wherein the second obtaining module calculates the three-phase voltage of the driving motor according to the following formula:
wherein, V u 、V v 、V w Is the three-phase voltage, V, of the drive motor dc Is the DC bus voltage, D u 、D v 、D w Is the duty ratio of a switch tube control signal in the inverter, i u 、i v 、i w As three-phase current of the drive motor, T d 、T on 、T off The dead time, the conduction time and the turn-off time of the switch tube control signal in the inverter are respectively.
11. The control device of the electric vehicle driving motor according to claim 10, wherein the second obtaining module calculates a stator flux linkage of the driving motor according to the following formula:
therein, Ψ α 、Ψ β The alpha-axis and beta-axis components, u, of the stator flux linkage of the drive motor α 、u β Alpha-axis and beta-axis components, i, of the stator voltage of the drive motor, respectively α 、i β Are respectively the alpha-axis and beta-axis components, R, of the stator current of the drive motor s And the resistance value of the stator phase winding in the driving motor is obtained.
12. The control device of the electric vehicle driving motor according to claim 11, wherein the second obtaining module calculates the current output torque of the driving motor according to the following formula:
wherein, T e And p is the number of pole pairs of the driving motor, wherein the current output torque of the driving motor is the current output torque of the driving motor.
13. The control device of the electric vehicle driving motor according to claim 12, wherein the control module is specifically configured to:
judging whether the torque difference value is larger than a first threshold value or not;
if the torque difference value is less than or equal to the first threshold value, maintaining the current state of the driving motor;
if the torque difference value is larger than the first threshold value, further judging whether the torque difference value is smaller than a second threshold value, wherein the second threshold value is larger than the first threshold value;
if the torque difference value is smaller than the second threshold value, reducing the direct-axis current and the quadrature-axis current of the driving motor by a first proportion;
if the torque difference value is larger than or equal to the second threshold value, further judging whether the torque difference value is smaller than a third threshold value, wherein the third threshold value is larger than the second threshold value;
if the torque difference is less than the third threshold, reducing the direct axis current and the quadrature axis current of the drive motor by a second proportion, wherein the second proportion is greater than the first proportion;
and if the torque difference value is larger than or equal to the third threshold value, controlling all upper bridge arms in the inverter to be closed and all lower bridge arms in the inverter to be opened, or controlling all lower bridge arms in the inverter to be closed and all upper bridge arms in the inverter to be opened.
14. An electric vehicle characterized by comprising the control device of the electric vehicle drive motor according to any one of claims 8 to 13.
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