CN107919827B - 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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CN107919827B
CN107919827B CN201711148690.5A CN201711148690A CN107919827B CN 107919827 B CN107919827 B CN 107919827B CN 201711148690 A CN201711148690 A CN 201711148690A CN 107919827 B CN107919827 B CN 107919827B
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driving motor
current
stator
axis
torque
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CN107919827A (en
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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 the electric vehicle, so that the actual output torque of the motor cannot be detected in real time, and 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 to some extent, one of the technical problems in the art described above. 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, an embodiment of a first aspect of the present invention provides a method for controlling a driving motor of an electric vehicle, including 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.
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 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.
Specifically, the three-phase voltage of the driving motor is calculated according to the following formula:
Figure BDA0001473022050000021
wherein, Vu、Vv、VwIs the three-phase voltage, V, of the drive motordcFor the DC bus voltage, Du、Dv、DwIs the duty ratio of the control signal of the switch tube in the inverter, iu、iv、iwIs a three-phase current of the drive motor, Td、Ton、ToffThe dead time, the conduction time and the turn-off time of the switch tube control signal in the inverter are respectively.
Further, the stator flux linkage of the driving motor is calculated according to the following formula:
Figure BDA0001473022050000022
therein, Ψα、Ψβα -axis, β -axis components, u, respectively, of the stator flux linkage of the drive motorα、uβα -axis, β -axis components, i, respectively, of the stator voltage of the drive motorα、iβα -axis, β -axis components, R, respectively, of the stator current of the drive motorsAnd the resistance value of the stator phase winding in the driving motor is obtained.
Further, the current output torque of the drive motor is calculated according to the following formula:
Figure BDA0001473022050000031
wherein, TeAnd 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 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 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 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 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 second obtaining module calculates the three-phase voltage of the driving motor according to the following formula:
Figure BDA0001473022050000041
wherein, Vu、Vv、VwIs the three-phase voltage, V, of the drive motordcFor the DC bus voltage, Du、Dv、DwIs the duty ratio of the control signal of the switch tube in the inverter, iu、iv、iwIs a three-phase current of the drive motor, Td、Ton、ToffThe 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:
Figure BDA0001473022050000042
therein, Ψα、Ψβα -axis, β -axis components, u, respectively, of the stator flux linkage of the drive motorα、uβα -axis, β -axis components, i, respectively, of the stator voltage of the drive motorα、iβα -axis, β -axis components, R, respectively, of the stator current of the drive motorsAnd 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:
Figure BDA0001473022050000043
wherein, TeAnd 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 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.
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 the specific implementation manner thereof may refer to the above embodiment, and is not described herein again to avoid 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, the method for controlling a driving motor of an electric vehicle according to an embodiment of the present invention includes the following steps:
and S1, acquiring 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.
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, 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 DC 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 voltage of the driving motor may be calculated according to a duty ratio of a switching tube control signal in the inverter, a voltage of the direct current, and a dead time, an on time, and an 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 the 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 the 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 the 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 the 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 Pulse Width Modulation (PWM) signal output by an SVPWM (Space vector Pulse Width Modulation) module, where the PWM _ UT signal may control the switching tube of the upper bridge arm in the U-phase to be turned on or off, the PWM _ UB signal may control the switching tube of the lower bridge arm in the U-phase to be turned on or off, the PWM _ VT signal may control the switching tube of the upper bridge arm in the V-phase to be turned on or off, the PWM _ VT signal may control the switching tube of the lower bridge arm in the V-phase to be turned on or off, the PWM _ WT signal may control the switching tube of the upper bridge arm in the W-phase to be turned on or off, and the PWM _ WT signal may control the switching tube of the lower bridge arm in the W-phase 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 inverteru、Dv、DwThe three-phase voltage V of the driving motor can be obtained by carrying out phase voltage calculationu、Vv、Vw. Specifically, the three-phase voltage of the driving motor may be calculated according to the following formula:
Figure BDA0001473022050000061
wherein, Vu、Vv、VwThree-phase voltage, V, for driving electric motorsdcIs a DC bus voltage Du、Dv、DwFor duty cycle, i, of the control signal of the switching tube in the inverteru、iv、iwThree-phase current, T, for driving electric motorsd、Ton、ToffThe 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, three-phase voltages V of the driving motor may be appliedu、Vv、VwClark conversion is performed to obtain α -axis and β -axis components u of stator voltage of driving motorα、uβAccordingly, α -axis and β -axis components u of the stator voltage of the drive motor can be obtained more accuratelyα、uβ。
In other embodiments of the present invention, in addition to obtaining the stator voltage under the stationary rectangular coordinate system of the driving motor by the above-mentioned manner, as shown in fig. 2, the given value of the direct-axis voltage of the driving motor can be directly output by the PI controller
Figure BDA0001473022050000075
Sum-quadrature voltage set point
Figure BDA0001473022050000072
The direct-axis voltage set value of the driving motor
Figure BDA0001473022050000073
Sum-quadrature voltage set point
Figure BDA0001473022050000074
α shaft and β shaft components u of stator voltage of the driving motor can be obtained after Park transformation (the included angle between a direct shaft and a quadrature shaft can be a rotor angle theta obtained by decoding the position of the IPMSM)α、uβ。
In the present inventionIn one embodiment, the three-phase current of the driving motor can be converted to obtain the stator current of the driving motor in a static rectangular coordinate system. As shown in fig. 2, three-phase currents i to drive the motor can be appliedu、iv、iwClark conversion is carried out to obtain α -axis and β -axis components i of stator current of a driving motorα、iβ。
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 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 correspondence relationship may be stored in advance in the form of a graph, and thus, as shown in fig. 3, the resistance Rs of the stator phase winding of the driving motor may be obtained from the graph correspondingly 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 component u passes through α -axis and β -axis of the stator voltage of the driving motorα、uβα -axis and β -axis components i of stator current of driving motorα、iβResistance R of stator phase winding in driving motorsPerforming flux linkage calculation to obtain stator flux linkage psi of the driving motorα、Ψβ. Specifically, the stator flux linkage of the drive motor can be calculated by the following formula:
Figure BDA0001473022050000071
therein, Ψα、Ψβα -axis and β -axis components, u, of the stator flux linkage of the drive motor, respectivelyα、uβα -axis and β -axis components, i, of the stator voltage of the drive motor, respectivelyα、iβα -axis, β -axis components, R, respectively, of the stator current of the drive motorsIs 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 α -axis and β -axis components i of the stator current passing through the drive motor in the above-described embodimentα、iβα -axis, β -axis component Ψ of the stator flux linkage of the drive motorα、ΨβAnd calculating the output torque of the pole pair number p of the driving motor to obtain the current output torque T of the driving motoreSpecifically, the current output torque of the drive motor may be calculated according to the following formula:
Figure BDA0001473022050000081
wherein, TeP is the number of pole pairs of the drive motor for the current output torque of the drive motor.
S3, a torque difference between the current output torque and the target torque is obtained. 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 adjustedeAnd target torque TcmdThe torque deviation determination may be made, specifically, by calculating the current output torque TeAbsolute value of (d) and target torque TcmdObtaining the current output torque T by the difference of the absolute values ofeAnd target torque TcmdDifference in torque Δ T betweeneI.e. Delta Te＝|Te|-|Tcmd|。
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 determinedeIf it is greater than the first threshold Te 1. If the torque difference Δ TeIs less than or equal to the first threshold Te1, the current state of the drive motor, that is, the current output torque and target of the drive motor is maintainedThe deviation of 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 the moment, the driving motor normally runs and can keep the current state of the driving motor.
If the torque difference Δ TeIf the torque difference value is larger than the first threshold Te1, the torque difference value Delta T is further judgedeIs less than a second threshold Te2, wherein the second threshold Te2 is greater than the first threshold Te 1.
If the torque difference Δ TeLess than the second threshold Te2, the direct-axis current and quadrature-axis current of the drive motor are reduced by the first ratio. If the torque difference Δ TeWhen the torque difference value is larger than or equal to the second threshold value Te2, the torque difference value Delta T is further judgedeIs less than a third threshold Te3, wherein the third threshold Te3 is greater than the second threshold Te 2.
If the torque difference Δ TeLess than the third threshold Te3, the direct axis current and quadrature axis current of the drive motor are reduced by a second ratio.
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 Kid _ limit of the respective direct-axis current and quadrature-axis current can be output to the current distribution module by the control device to limit the direct-axis current and the quadrature-axis current of the driving motor. For example, when the torque difference Δ TeWhen the first ratio is greater than the first threshold Te1 and less than the second threshold Te2, the first ratio may be 1/2, that is, the limiting coefficients Kid _ limit and Kiq _ limit, both of which are 1/2, may be output to the current distribution module by the control 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 TeWhen 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 limiting coefficients Kid _ limit and Kiq _ limit, both of which are 1/3, may be output to the current distribution module by 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 TeAnd if the current is larger 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 greatereWhen the current is greater 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 opened, or the lower bridge arm and the upper bridge arm in the inverter can be controlled to be completely closed and completely opened, so that the IPMSM can be controlled to stop running, and 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 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 motoru、iv、iwThe temperature T of the driving motor and the direct current bus voltage Vdc of the driving motor.
S202, judging whether n > n1 exists. If yes, step S203, step S205, step S206 may be performed, respectively; if not, step S202 continues. The n1 can be a preset rotating speed, the preset rotating speed n1 can be calibrated according to actual conditions, 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 inverteru、Dv、DwVoltage V of direct currentdcAnd the dead time T of the control signal of the switch tube in the inverterdOn time TonAnd off time ToffAnd 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:
Figure BDA0001473022050000101
wherein, Vu、Vv、VwThree-phase voltage, V, for driving electric motorsdcIs a DC bus voltage, Du、Dv、DwFor duty cycle, i, of the control signal of the switching tube in the inverteru、iv、iwThree-phase current, T, for driving electric motorsd、Ton、ToffThe dead time, the conduction time and the turn-off time of the control signal of the switch tube in the inverter are respectively.
S204, converting the three-phase voltage of the driving motor to obtain the stator voltage of the driving motor under a static rectangular coordinate system, wherein Clark conversion can be carried out on the three-phase voltage of the driving motor to obtain α -axis and β -axis components of the stator voltage of the driving motor, namely uα、uβ。
S205, three phases of the motor are drivenThe three-phase current of the driving motor can be subjected to Clark conversion to obtain α -axis and β -axis components, i.e. i, of the stator current of the driving motorα、iβ。
And S206, acquiring the resistance Rs of the stator phase winding in the driving motor according to the temperature T of the driving motor.
S207, calculating the stator flux linkage of the driving motor according to the stator voltage of the driving motor in the static rectangular coordinate system, the stator current of the driving motor in the static rectangular coordinate system and the resistance value of the stator phase winding in the driving motor, namely, the α -axis and β -axis components of the stator voltage of the driving motor, namely, u, obtained in the step S204α、uβα -axis, β -axis components, i.e., i, of the stator current of the drive motor acquired by step S205α、iβAnd calculating the stator flux linkage of the drive motor from the resistance values of the stator phase windings in the drive motor obtained in step S206.
Specifically, the stator flux linkage of the drive motor can be calculated by the following formula:
Figure BDA0001473022050000102
therein, Ψα、Ψβα -axis and β -axis components, u, of the stator flux linkage of the drive motor, respectivelyα、uβα -axis and β -axis components, i, of the stator voltage of the drive motor, respectivelyα、iβα -axis, β -axis components, R, respectively, of the stator current of the drive motorsIs 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, the α -axis and β -axis components, i.e., Ψ, of the stator flux linkage of the drive motor obtained in step S207α、Ψβα -axis, β -axis components, i.e., i, of the stator current of the drive motor acquired by step S205α、iβAnd calculating the current output torque of the driving motor according to the following formula:
Figure BDA0001473022050000111
wherein, TeP 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 | quantity | Tcmd |.
S210, determine whether Δ Te < Te1 exists. If yes, go to step S211; if not, step S212 is performed.
S211, the current state of the driving motor is maintained.
S212, it is determined whether Δ Te < Te2 exists. If so, go to step S213; if not, step S214 is performed.
S213 reduces the direct axis current and quadrature axis current of the drive motor to 1/2 of the direct axis current and quadrature axis current when the characteristic output other than the drive motor is output.
S214, it is determined whether Δ Te < Te3 exists. If so, go to step S215; if not, step S216 is performed.
S215, 1/3 of the direct axis current and the quadrature axis current when the direct axis current and the quadrature axis current of the driving motor are reduced to the characteristic output other than the driving motor.
And S216, controlling all upper bridge arms and all lower bridge arms in the inverter to be closed, or controlling all lower bridge arms and all upper bridge arms in the inverter to be closed.
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 may 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 one 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 a switch tube control signal in the inverter, a voltage of the direct current, and a dead time, an on time, and an 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. 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 second obtaining module 200 obtains the duty ratio D of the control signal of the switch tube in the inverter through the comparisonu、Dv、DwThe phase voltage calculation can be carried outObtaining the three-phase voltage V of the driving motoru、Vv、Vw. Specifically, the second obtaining module 200 may calculate the three-phase voltages of the driving motor according to the following formulas:
Figure BDA0001473022050000121
wherein, Vu、Vv、VwThree-phase voltage, V, for driving electric motorsdcIs a DC bus voltage Du、Dv、DwFor duty cycle, i, of the control signal of the switching tube in the inverteru、iv、iwThree-phase current, T, for driving electric motorsd、Ton、ToffThe 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 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 motoru、Vv、VwClark conversion is performed to obtain α -axis and β -axis components u of stator voltage of driving motorα、uβAccordingly, α -axis and β -axis components u of the stator voltage of the drive motor can be obtained more accuratelyα、uβ。
In other embodiments of the present invention, in addition to obtaining the stator voltage under the stationary rectangular coordinate system of the driving motor by the above-mentioned manner, as shown in fig. 2, the given value of the direct-axis voltage of the driving motor can be directly output by the PI controller
Figure BDA0001473022050000132
Sum-quadrature voltage set point
Figure BDA0001473022050000133
The direct-axis voltage set value of the driving motor
Figure BDA0001473022050000134
Sum-quadrature voltage set point
Figure BDA0001473022050000135
α shaft and β shaft components u of stator voltage of the driving motor can be obtained after Park transformation (the included angle between a direct shaft and a quadrature shaft can be a rotor angle theta obtained by decoding the position of the IPMSM)α、uβ。
In one 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 conversion 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 motorα、iβ。
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 the form of a table, so that 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, as shown in fig. 3.
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 acquisition module 200 passes the α -axis, β -axis components u of the stator voltage to the drive motorα、uβα -axis and β -axis components i of stator current of driving motorα、iβResistance R of stator phase winding in driving motorsPerforming flux linkage calculation to obtain stator flux linkage psi of the driving motorα、Ψβ. Specifically, the second acquisitionThe module 200 may calculate the stator flux linkage of the drive motor by the following equation:
Figure BDA0001473022050000131
therein, Ψα、Ψβα -axis and β -axis components, u, of the stator flux linkage of the drive motor, respectivelyα、uβα -axis and β -axis components, i, of the stator voltage of the drive motor, respectivelyα、iβα -axis, β -axis components, R, respectively, of the stator current of the drive motorsIs 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 component i of the stator current of the driving motor through α -axis and β -axisα、iβα -axis, β -axis component Ψ of the stator flux linkage of the drive motorα、ΨβAnd calculating the output torque of the pole pair number p of the driving motor to obtain the current output torque T of the driving motoreSpecifically, the current output torque of the drive motor may be calculated according to the following formula:
Figure BDA0001473022050000141
wherein, TeP 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 TeAnd target torque TcmdThe 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 TeAbsolute value of (d) and target torque TcmdObtaining the current output torque T by the difference of the absolute values ofeAnd target torque TcmdDifference in torque Δ T betweeneI.e. Delta Te＝|Te|-|TcmdL. Wherein the target torque TcmdCan 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 TeIf it is greater than the first threshold Te 1.
If the torque difference Δ TeIf the current state of the driving motor is less 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 less than the absolute value of the target torque, and the driving motor operates normally at this time, so that the current state of the driving motor can be maintained.
If the torque difference Δ TeIf the torque difference value is larger than the first threshold Te1, the torque difference value Delta T is further judgedeIs less than a second threshold Te2, wherein the second threshold Te2 is greater than the first threshold Te 1.
If the torque difference Δ TeLess than the second threshold Te2, the direct-axis current and quadrature-axis current of the drive motor are reduced by the first ratio. If the torque difference Δ TeWhen the torque difference value is larger than or equal to the second threshold value Te2, the torque difference value Delta T is further judgedeIs less than a third threshold Te3, wherein the third threshold Te3 is greater than the second threshold Te 2.
If the torque difference Δ TeLess than the third threshold Te3, the direct axis current and quadrature axis current of the drive motor are reduced by a second ratio.
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 control device (including the first acquiring module 100, the second acquiring module 200, the first acquiring module, the second acquiring module, the third acquiring module, the fourth acquiring module, the fifth acquiring module, the sixth acquiring module,The third obtaining module 300 and the control module 400) may output the limiting coefficients Kid _ limit and Kiq _ limit of the respective direct-axis current and quadrature-axis current to the current distribution module to limit the direct-axis current and the quadrature-axis current of the driving motor. For example, when the torque difference Δ TeWhen the first ratio is greater than the first threshold Te1 and less than the second threshold Te2, the first ratio may be 1/2, that is, the limiting coefficients Kid _ limit and Kiq _ limit, both of which are 1/2, may be output to the current distribution module by the control 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 TeWhen 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 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 TeAnd if the current is larger 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 greatereWhen the current is greater 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 can be controlled to stop running, and 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.
The invention further provides an electric automobile corresponding to the embodiment.
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 the specific implementation manner thereof may refer to the above embodiment, and is not described herein again to avoid 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 implicitly indicating 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 expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. 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 being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first 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 is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, 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 (12)

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, 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, 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 direct-current bus voltage comprises:
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;
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;
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 control method of the driving motor of the electric vehicle according to claim 1, wherein the three-phase voltage of the driving motor is calculated according to the following formula:
Figure FDA0002252261530000011
wherein, Vu、Vv、VwIs the three-phase voltage, V, of the drive motordcFor the DC bus voltage, Du、Dv、DwIs the duty ratio of the control signal of the switch tube in the inverter, iu、iv、iwIs a three-phase current of the drive motor, Td、Ton、ToffThe dead time, the conduction time and the turn-off time of the switch tube control signal in the inverter are respectively.
3. The control method of the electric vehicle driving motor according to claim 2, wherein the stator flux linkage of the driving motor is calculated according to the following formula:
Figure FDA0002252261530000021
therein, Ψα、Ψβα -axis, β -axis components, u, respectively, of the stator flux linkage of the drive motorα、uβα -axis, β -axis components, i, respectively, of the stator voltage of the drive motorα、iβα -axis, β -axis components, R, respectively, of the stator current of the drive motorsAnd the resistance value of the stator phase winding in the driving motor is obtained.
4. The control method of the electric vehicle driving motor according to claim 3, wherein the current output torque of the driving motor is calculated according to the following formula:
Figure FDA0002252261530000022
wherein, TeAnd 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.
5. The method for controlling the driving motor of the electric vehicle according to claim 4, wherein 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 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.
6. 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 5.
7. 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 configured to obtain a 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 when the rotation speed of the driving motor is greater than a preset rotation speed, where 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;
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;
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.
8. The control device of the electric vehicle driving motor according to claim 7, wherein the second obtaining module calculates the three-phase voltage of the driving motor according to the following formula:
Figure FDA0002252261530000031
wherein, Vu、Vv、VwIs the three-phase voltage, V, of the drive motordcFor the DC bus voltage, Du、Dv、DwIs the duty ratio of the control signal of the switch tube in the inverter, iu、iv、iwIs a three-phase current of the drive motor, Td、Ton、ToffThe dead time, the conduction time and the turn-off time of the switch tube control signal in the inverter are respectively.
9. The control device of the electric vehicle driving motor according to claim 8, wherein the second obtaining module calculates the stator flux linkage of the driving motor according to the following formula:
Figure FDA0002252261530000032
therein, Ψα、Ψβα -axis, β -axis components, u, respectively, of the stator flux linkage of the drive motorα、uβα -axis and β -axis minutes of stator voltage of the driving motor respectivelyAmount, iα、iβα -axis, β -axis components, R, respectively, of the stator current of the drive motorsAnd the resistance value of the stator phase winding in the driving motor is obtained.
10. The control device of the electric vehicle driving motor according to claim 9, wherein the second obtaining module calculates the current output torque of the driving motor according to the following formula:
Figure FDA0002252261530000041
wherein, TeAnd 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.
11. The control device of the electric vehicle driving motor according to claim 10, 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 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.
12. An electric vehicle characterized by comprising the control device of the electric vehicle drive motor according to any one of claims 7 to 11.
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