CN113733928B - Control method and device of vehicle, control equipment and automobile - Google Patents

Control method and device of vehicle, control equipment and automobile Download PDF

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Publication number
CN113733928B
CN113733928B CN202010461736.4A CN202010461736A CN113733928B CN 113733928 B CN113733928 B CN 113733928B CN 202010461736 A CN202010461736 A CN 202010461736A CN 113733928 B CN113733928 B CN 113733928B
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Prior art keywords
battery
vehicle
torque
discharge power
target
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CN113733928A (en
Inventor
张小帅
梁海强
储琦
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Beijing Electric Vehicle Co Ltd
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Beijing Electric Vehicle Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/10—Vehicle control parameters
    • B60L2240/12—Speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • B60L2240/423—Torque
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/54—Drive Train control parameters related to batteries
    • B60L2240/545—Temperature
    • 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
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

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

Abstract

The invention provides a control method and device of a vehicle, control equipment and an automobile, wherein the control method comprises the following steps: acquiring a vehicle running state of a target vehicle; determining a target torque according to the vehicle running state; transmitting the target torque to a motor control unit MCU so that the motor outputs the target torque; wherein the vehicle running state includes an accelerator pedal opening, a vehicle speed, and a temperature change rate of the battery. According to the scheme, the battery discharge power is processed, so that the test requirement can be met, and the drivability is improved; the uncomfortable driving experience caused by power fluctuation when the vehicle accelerates or climbs a slope in the running process of the vehicle in a high-temperature environment can be avoided; in addition, the temperature change rate is introduced to perform torsion limiting treatment on the over-temperature working condition in advance, so that the condition of overhigh battery temperature is avoided, and the safety of the vehicle battery is further protected.

Description

Control method and device of vehicle, control equipment and automobile
Technical Field
The present invention relates to the field of automobiles, and in particular, to a method and apparatus for controlling a vehicle, a control device, and an automobile.
Background
According to the highest speed test requirement in GB/T18385-2005 electric automobile dynamic performance test method, the highest speed of the automobile under the full throttle working condition is stable. However, due to the characteristics of the battery, the condition that the vehicle speed of the vehicle is not satisfied when the battery runs at the maximum power may be caused, that is, when the full throttle occurs in the test process, the discharge power of the battery may fluctuate due to the fluctuation of the battery temperature, so that the vehicle speed fluctuates, and finally, the test requirement of the vehicle speed stability cannot be satisfied.
In addition, the vehicle has a high power discharge demand of the battery when the vehicle starts the racetrack mode, and the battery is required to meet the conditions that allow a large power to be instantaneously discharged and ensure the thermal balance of the battery.
Disclosure of Invention
The embodiment of the invention provides a vehicle control method, a device, control equipment and an automobile, which are used for solving the problem of unstable speed of an electric automobile caused by battery heat balance in the prior art.
In order to solve the technical problems, the invention adopts the following technical scheme:
according to an aspect of the present invention, there is provided a control method of a vehicle, including:
acquiring a vehicle running state of a target vehicle;
determining a target torque according to the vehicle running state;
transmitting the target torque to a motor control unit MCU so that the motor outputs the target torque;
wherein the vehicle running state includes an accelerator pedal opening, a vehicle speed, and a temperature change rate of the battery.
Optionally, the determining the target torque according to the vehicle running state includes:
determining the required torque of the target vehicle according to the opening of the accelerator pedal and the vehicle speed, and determining a torque limiting coefficient corresponding to the current temperature change rate of the battery of the target vehicle according to the corresponding relation between the temperature change rate of the battery and the torque limiting coefficient;
and determining the target torque according to the torque limiting coefficient and the required torque.
Optionally, the determining the target torque according to the vehicle running state includes:
obtaining the maximum allowable discharge power of the battery of the target vehicle; wherein the maximum discharge power is calculated and obtained by a battery management system BMS according to the battery working state of the target vehicle;
judging whether a first mode of the target vehicle is started or not when the opening of the accelerator pedal is larger than or equal to a preset opening value;
if the first mode is not started, controlling the battery discharge power of the target vehicle not to exceed the maximum discharge power;
and determining a target torque according to the accelerator pedal opening, the battery discharging power and the battery working state.
Optionally, the battery operating state includes a battery temperature, a battery cell voltage, and a state of charge SOC.
Optionally, the first mode comprises a racetrack mode.
Optionally, the control method further includes:
according to the corresponding relation between the maximum discharge power and time, adjusting the maximum discharge power every other preset time length;
wherein the maximum discharge power after adjustment is smaller than the maximum discharge power before adjustment.
Optionally, the method further comprises:
stopping controlling the battery discharge power when the vehicle working condition changes;
the vehicle working condition change comprises the step of changing the opening rate of the accelerator pedal to exceed a preset value, the step of switching and the mode of switching.
According to another aspect of the present invention, there is provided a control device of a vehicle, including:
the data acquisition module is used for acquiring the vehicle running state of the target vehicle;
the torque determining module is used for determining target torque according to the running state of the vehicle;
the torque transmitting module is used for transmitting the target torque to the motor control unit MCU so that the motor outputs the target torque;
wherein the vehicle running state includes an accelerator pedal opening, a vehicle speed, and a temperature change rate of the battery.
According to another aspect of the present invention, there is provided a control apparatus including a memory, a processor, and a program stored on the memory and executable on the processor; the processor implements the control method as described above when executing the program.
According to another aspect of the present invention, there is provided an automobile including the control device as described above.
The beneficial effects of the invention are as follows:
according to the scheme, the battery discharge power is processed, so that the test requirement can be met, and the drivability is improved; the uncomfortable driving experience caused by power fluctuation when the vehicle accelerates or climbs a slope in the running process of the vehicle in a high-temperature environment can be avoided; in addition, the temperature change rate is introduced to perform torsion limiting treatment on the over-temperature working condition in advance, so that the condition of overhigh battery temperature is avoided, and the safety of the vehicle battery is further protected.
Drawings
FIG. 1 is a schematic diagram of a method for controlling the thermal balance of a battery according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a control device for battery thermal balance according to an embodiment of the present invention;
FIG. 3 is a system frame diagram of battery thermal balance control according to an embodiment of the present invention;
fig. 4 is a flowchart illustrating a battery discharge power process performed in the method for controlling battery thermal balance according to the embodiment of the present invention;
fig. 5 shows a flow chart of torque limiting by a temperature change rate in the method for controlling battery thermal balance according to the embodiment of the invention.
Detailed Description
The present invention will be described in detail below with reference to the drawings and the specific embodiments thereof in order to make the objects, technical solutions and advantages of the present invention more apparent.
The invention provides a vehicle control method and device, control equipment and an automobile aiming at the problem of unstable vehicle speed of an electric automobile caused by battery heat balance.
As shown in fig. 1, one embodiment of the present invention provides a control method for a vehicle, including:
s11: acquiring a vehicle running state of a target vehicle;
s12: determining a target torque according to the vehicle running state;
s13: the target torque is sent to the motor control unit MCU so that the motor outputs the target torque.
It should be noted that, in order to solve the problem of battery discharge power fluctuation caused by battery thermal balance, the vehicle controller (Vehicle Control Unit, abbreviated as VCU) may determine the output of the battery discharge power at this time according to the vehicle running state (i.e. the accelerator opening and other signal inputs of the vehicle), and finally determine the target torque, and then output the target torque to the motor control unit (Motor Control Unit, abbreviated as MCU). Optionally, the vehicle running state includes an accelerator pedal opening, a vehicle speed, and a temperature change rate of the battery.
That is, the target torque can be determined by the vehicle running state to achieve the purpose of controlling the vehicle speed.
Wherein, the following two schemes can be adopted for control: firstly, the battery discharging power is controlled so that the battery discharging power can only be reduced and cannot be increased under certain conditions, and the problem of battery heat balance is avoided; and secondly, torque limitation is carried out according to the temperature change rate of the battery so as to ensure the heat balance of the battery.
Specifically, according to one embodiment of the present invention, the determining the target torque according to the running state of the vehicle includes:
determining the required torque of the target vehicle according to the opening of the accelerator pedal and the vehicle speed, and determining a torque limiting coefficient corresponding to the current temperature change rate of the battery of the target vehicle according to the corresponding relation between the temperature change rate of the battery and the torque limiting coefficient;
and determining the target torque according to the torque limiting coefficient and the required torque.
The corresponding relation between the temperature change rate of the battery and the torsion limiting coefficient can be obtained through a whole vehicle experiment to form a relation table, so that the torsion limiting is performed by utilizing the highest temperature change rate of the battery. That is, it is possible to secure the heat balance of the battery by performing torque limitation on the battery temperature increase when the battery is over-warmed, that is, when the rate of change in the temperature of the battery (the rate of battery temperature increase) is high. Specifically, the VCU may adjust the torque and then determine the target torque, and then output the target torque to the motor, so as to avoid excessive output power, thereby avoiding over-temperature of the battery and further avoiding fluctuation of the vehicle speed.
As shown in fig. 5, the temperature change rate of the battery may be calculated by a first formula:
wherein DeltaT represents the rate of change of the temperature of the battery, T t The temperature value at the time t is represented; t (T) t-1 The temperature value at the time t-1 is represented; dt represents the time interval between time t and time t-1.
And (3) carrying out table lookup (namely the relation table) according to delta T to obtain a torque limiting coefficient (namely a torque limiting coefficient), and sending the product of the torque limiting coefficient and the required torque as target torque to the motor for execution.
It should be noted that, for a battery product in which the battery temperature is greatly affected by the environment, the battery temperature also has an influence on the magnitude of the energy recovery torque, and may bring bad driving experience such as vehicle cocking during recovery. Therefore, the battery feedback power can be controlled under the energy recovery working condition, namely, the battery feedback power is only allowed to be reduced and cannot be increased by using a battery feedback power taking strategy, and the battery feedback power taking control is stopped after the energy recovery working condition exits.
By the method, when the temperature of the battery rises too fast, the torque is limited through the temperature change rate of the battery, so that the aim of controlling the heat balance of the battery is fulfilled.
According to another embodiment of the present invention, the determining the target torque according to the vehicle running state includes:
obtaining the maximum allowable discharge power of the battery of the target vehicle; wherein the maximum discharge power is calculated and obtained by a battery management system BMS according to the battery working state of the target vehicle;
judging whether a first mode of the target vehicle is started or not when the opening of the accelerator pedal is larger than or equal to a preset opening value;
if the first mode is not started, controlling the battery discharge power of the target vehicle not to exceed the maximum discharge power;
and determining a target torque according to the accelerator pedal opening, the battery discharging power and the battery working state.
Optionally, the first mode comprises a racetrack mode.
It should be noted that, as shown in fig. 3, the maximum allowable discharge power of the battery may be output to the VCU by a battery management system (Battery Management System, abbreviated as BMS), where the maximum discharge power is calculated by the battery management system BMS according to the battery operating state of the target vehicle, and optionally, the battery operating state includes a battery temperature, a battery cell voltage and a state of charge SOC. That is, the maximum discharge power may vary according to the battery operating state, and the BMS may update the maximum discharge power according to the variation of the battery operating state.
According to one embodiment of the present invention, the VCU may detect the vehicle operating condition, and when the accelerator opening is greater than or equal to a preset opening value, for example, when the accelerator opening is greater than or equal to 95% (the operating condition at this time may be regarded as full throttle operation), control the allowable discharge power of the battery. The preset opening value can be obtained through calibration according to actual conditions; in addition, since the vehicle in some special modes (i.e., the first mode) requires a large battery discharge power, such as the racetrack mode, it is necessary to determine the vehicle operation mode to perform the differential processing.
Specifically, according to one embodiment of the present invention, the battery discharge power may be processed according to the battery discharge power processing flowchart shown in fig. 4, so as to achieve the purpose of controlling the heat balance of the battery:
s41: starting;
s42: judging whether the current gear of the vehicle is a driving gear, if so, executing S44; if not, then S43 is executed;
s43: controlling the discharge power output of the battery to be 0;
s44: judging whether the accelerator pedal opening is greater than or equal to 95%, if so, executing S46; if not, executing S45;
s45: the battery discharge power is normally output, namely, special treatment is not carried out on the battery discharge power;
s46: judging whether the track mode is started, if yes, executing S48; if not, then S47 is performed;
s47: the battery discharge power is not allowed to be increased and output;
s48: the battery discharge power is amplified and output instantly;
s49: and (5) ending.
That is, when the accelerator opening is 95% or more and the racing mode is not on, the battery discharge power is controlled to be only allowed to be lowered and not to be raised, so that the purposes of battery heat balance and no fluctuation of the vehicle speed in the climbing test are achieved. On the other hand, when the accelerator opening is greater than or equal to 95%, and the racing mode is already on, the current battery discharge power is allowed to output greater power to meet the greater battery discharge power demand of the vehicle in the racing mode.
Wherein, the control of the battery discharge power only allows the decrease and not the increase, and can be realized by the following ways:
optionally, the control method further includes: according to the corresponding relation between the maximum discharge power and time, adjusting the maximum discharge power every other preset time length; wherein the maximum discharge power after adjustment is smaller than the maximum discharge power before adjustment.
That is, when the accelerator opening is greater than or equal to 95%, that is, when the vehicle is running at full throttle, it is necessary to adjust the maximum discharge power at intervals of a preset time to control the battery discharge power to be gradually reduced, achieving the effect of allowing only a descent and not allowing an ascent, thereby controlling the battery heat balance. Specifically, the corresponding relation between the maximum discharge power and time can be obtained according to experiments, namely, how long the maximum discharge power of a certain value is allowed to be maintained without affecting the vehicle speed fluctuation, and the corresponding time is taken as the preset time length, that is, the preset time length can be calibrated according to actual conditions. When the duration of the allowable hold is reached, a reduction control of the maximum discharge power is required to control the battery discharge power output of the vehicle.
In addition, the preset duration can be displayed on the instrument in a countdown mode to prompt a driver how long the current battery discharge power can be kept, so that the driver can prepare a certain thought for the reduction control of the battery discharge power by the vehicle, and driving experience can be improved.
Accordingly, similar control can be performed on the vehicle in the case of the track mode being turned on to avoid problems in battery thermal balance. Specifically, in the racetrack mode, the instantaneous power of the battery is relatively high, and at this time, the BMS can calculate the time for high-power stable output and output the time to the VCU, and the VCU outputs the time signal to the meter. This time gradually decreases when the battery thermal balance does not allow the battery management unit to output such a large power until the transition to the normal output power state. That is, in the racetrack mode, the battery discharge power is allowed to be instantaneously amplified, and the battery discharge power can be also controlled to be reduced after the vehicle is operated for a period of time at high power, so as to prevent the occurrence of a problem in battery heat balance.
In summary, according to the requirements of GB/T18385-2005 electric vehicle dynamic performance test method, the battery discharge power processing strategy provided by the embodiment of the invention can be used when the highest vehicle speed test is carried out, namely, the battery power is only allowed to be reduced but not allowed to be increased under the full throttle working condition, so as to ensure the stability of the vehicle speed.
Optionally, the control method further includes:
stopping controlling the battery discharge power when the vehicle working condition changes;
the vehicle working condition change comprises the step of changing the opening rate of the accelerator pedal to exceed a preset value, the step of switching and the mode of switching.
It should be noted that, in order to avoid the power shortage caused by the lack of recovery of the power after the power is taken out in other working conditions, a recovery strategy after the battery discharge power treatment may be set, which mainly includes a recovery strategy set according to the change of the accelerator pedal and the change of the working conditions, for example, the recovery of the battery discharge power may be allowed when the accelerator pedal is released.
Specifically, the recovery condition after allowing the battery discharge power to be processed may be set as: the battery discharge power is recovered when the accelerator pedal opening is changed, and it should be noted that the range of the accelerator pedal opening change can be defined according to the specific situation, for example, 50% change is recovered; or, allowing the battery discharge power to recover when the vehicle working condition changes, wherein the vehicle working condition changes comprise gear switching or mode switching, driving and recovery switching and the like.
That is, by the above arrangement, the situation that the power is insufficient due to the fact that the power cannot be recovered after the power is taken down can be avoided.
It is worth mentioning that when the battery characteristics are different (whether the battery is a liquid cooling battery or an air cooling battery), the battery temperature fluctuation condition is different, and the control method provided by the embodiment of the invention can enable the vehicle to meet the highest vehicle speed requirement of GB T18385-2005 electric vehicle dynamic performance test method under working conditions such as high temperature and high load, and meanwhile, the phenomenon of vehicle groveling can be avoided, and driving experience is ensured. In addition, because there is a direct relationship between battery temperature and battery power, the battery power processing strategy can also be implemented by processing the battery temperature.
In the embodiment of the invention, the battery discharge power is processed, so that the test requirement can be met, and the drivability is improved; the uncomfortable driving experience caused by power fluctuation when the vehicle accelerates or climbs a slope in the running process of the vehicle in a high-temperature environment can be avoided; in addition, the temperature change rate is introduced to perform torsion limiting treatment on the over-temperature working condition in advance, so that the condition of overhigh battery temperature is avoided, and the safety of the vehicle battery is further protected.
As shown in fig. 2, an embodiment of the present invention further provides a control device for a vehicle, including:
a data acquisition module 21 for acquiring a vehicle running state of the target vehicle;
a torque determination module 22 for determining a target torque based on the vehicle operating state;
a torque transmitting module 23 for transmitting the target torque to the motor control unit MCU so that the motor outputs the target torque.
It should be noted that, in order to solve the problem of battery discharge power fluctuation caused by battery thermal balance, the VCU may determine the output of the battery discharge power at this time according to the vehicle running state (i.e., the opening of the accelerator pedal and other signal inputs of the whole vehicle), and finally determine the target torque, and then output the target torque to the MCU. Optionally, the vehicle running state includes an accelerator pedal opening, a vehicle speed, and a temperature change rate of the battery.
That is, the target torque can be determined by the vehicle running state to achieve the purpose of controlling the vehicle speed.
Wherein, the following two schemes can be adopted for control: firstly, the battery discharging power is controlled so that the battery discharging power can only be reduced and cannot be increased under certain conditions, and the problem of battery heat balance is avoided; and secondly, torque limitation is carried out according to the temperature change rate of the battery so as to ensure the heat balance of the battery.
Specifically, according to one embodiment of the present invention, the torque determination module 22 includes:
the power determining unit is used for determining the required torque of the target vehicle according to the opening of the accelerator pedal and the vehicle speed, and determining the torque limiting coefficient corresponding to the current temperature change rate of the battery of the target vehicle according to the corresponding relation between the temperature change rate of the battery and the torque limiting coefficient;
and the first torque unit is used for determining the target torque according to the torque limiting coefficient and the required torque.
The corresponding relation between the temperature change rate of the battery and the torsion limiting coefficient can be obtained through a whole vehicle experiment to form a relation table, so that the torsion limiting is performed by utilizing the highest temperature change rate of the battery. That is, it is possible to secure the heat balance of the battery by performing torque limitation on the battery temperature increase when the battery is over-warmed, that is, when the rate of change in the temperature of the battery (the rate of battery temperature increase) is high. Specifically, the VCU may adjust the torque and then determine the target torque, and then output the target torque to the motor, so as to avoid excessive output power, thereby avoiding over-temperature of the battery and further avoiding fluctuation of the vehicle speed.
As shown in fig. 5, the temperature change rate of the battery may be calculated by a first formula:
wherein DeltaT represents the rate of change of the temperature of the battery, T t The temperature value at the time t is represented; t (T) t-1 The temperature value at the time t-1 is represented; dt represents the time interval between time t and time t-1.
And (3) carrying out table lookup (namely the relation table) according to delta T to obtain a torque limiting coefficient (namely a torque limiting coefficient), and sending the product of the torque limiting coefficient and the required torque as target torque to the motor for execution.
It should be noted that, for a battery product in which the battery temperature is greatly affected by the environment, the battery temperature also has an influence on the magnitude of the energy recovery torque, and may bring bad driving experience such as vehicle cocking during recovery. Therefore, the battery feedback power can be controlled under the energy recovery working condition, namely, the battery feedback power is only allowed to be reduced and cannot be increased by using a battery feedback power taking strategy, and the battery feedback power taking control is stopped after the energy recovery working condition exits.
Through the scheme, when the temperature of the battery rises too fast, the torque is limited through the temperature change rate of the battery, so that the purpose of controlling the heat balance of the battery is achieved.
According to another embodiment of the present invention, the torque determination module 22 includes:
a power determining unit, configured to obtain a maximum discharge power currently allowed by a battery of the target vehicle; wherein the maximum discharge power is calculated and obtained by a battery management system BMS according to the battery working state of the target vehicle;
a mode judging unit configured to judge whether a first mode of the target vehicle is on when the accelerator pedal opening is greater than or equal to a preset opening value;
a power control unit configured to control a battery discharge power of the target vehicle not to exceed the maximum discharge power if the first mode is not turned on;
and the second torque unit is used for determining target torque according to the opening degree of the accelerator pedal, the battery discharging power and the battery working state.
Optionally, the first mode comprises a racetrack mode.
It should be noted that, as shown in fig. 3, the maximum allowable discharge power of the battery may be output to the VCU by a battery management system (Battery Management System, abbreviated as BMS), where the maximum discharge power is calculated by the battery management system BMS according to the battery operating state of the target vehicle, and optionally, the battery operating state includes a battery temperature, a battery cell voltage and a state of charge SOC. That is, the maximum discharge power may vary according to the battery operating state, and the BMS may update the maximum discharge power according to the variation of the battery operating state.
According to one embodiment of the present invention, the VCU may detect the vehicle operating condition, and when the accelerator opening is greater than or equal to a preset opening value, for example, when the accelerator opening is greater than or equal to 95% (the operating condition at this time may be regarded as full throttle operation), control the allowable discharge power of the battery. The preset opening value can be obtained through calibration according to actual conditions; in addition, since the vehicle in some special modes (i.e., the first mode) requires a large battery discharge power, such as the racetrack mode, it is necessary to determine the vehicle operation mode to perform the differential processing.
Specifically, according to one embodiment of the present invention, the battery discharge power may be processed according to the battery discharge power processing flowchart shown in fig. 4, so as to achieve the purpose of controlling the heat balance of the battery:
s41: starting;
s42: judging whether the current gear of the vehicle is a driving gear, if so, executing S44; if not, then S43 is executed;
s43: controlling the discharge power output of the battery to be 0;
s44: judging whether the accelerator pedal opening is greater than or equal to 95%, if so, executing S46; if not, executing S45;
s45: the battery discharge power is normally output, namely, special treatment is not carried out on the battery discharge power;
s46: judging whether the track mode is started, if yes, executing S48; if not, then S47 is performed;
s47: the battery discharge power is not allowed to be increased and output;
s48: the battery discharge power is amplified and output instantly;
s49: and (5) ending.
That is, when the accelerator opening is 95% or more and the racing mode is not on, the battery discharge power is controlled to be only allowed to be lowered and not to be raised, so that the purposes of battery heat balance and no fluctuation of the vehicle speed in the climbing test are achieved. On the other hand, when the accelerator opening is greater than or equal to 95%, and the racing mode is already on, the current battery discharge power is allowed to output greater power to meet the greater battery discharge power demand of the vehicle in the racing mode.
Wherein, the control of the battery discharge power only allows the decrease and not the increase, and can be realized by the following ways:
optionally, the control device further includes:
the power adjustment module is used for adjusting the maximum discharge power every preset time length according to the corresponding relation between the maximum discharge power and time; wherein the maximum discharge power after adjustment is smaller than the maximum discharge power before adjustment.
That is, when the accelerator opening is greater than or equal to 95%, that is, when the vehicle is running at full throttle, it is necessary to adjust the maximum discharge power at intervals of a preset time to control the battery discharge power to be gradually reduced, achieving the effect of allowing only a descent and not allowing an ascent, thereby controlling the battery heat balance. Specifically, the corresponding relation between the maximum discharge power and time can be obtained according to experiments, namely, how long the maximum discharge power of a certain value is allowed to be maintained without affecting the vehicle speed fluctuation, and the corresponding time is taken as the preset time length, that is, the preset time length can be calibrated according to actual conditions. When the duration of the allowable hold is reached, a reduction control of the maximum discharge power is required to control the battery discharge power output of the vehicle.
In addition, the preset duration can be displayed on the instrument in a countdown mode to prompt a driver how long the current battery discharge power can be kept, so that the driver can prepare a certain thought for the reduction control of the battery discharge power by the vehicle, and driving experience can be improved.
Accordingly, similar control can be performed on the vehicle in the case of the track mode being turned on to avoid problems in battery thermal balance. Specifically, in the racetrack mode, the instantaneous power of the battery is relatively high, and at this time, the BMS can calculate the time for high-power stable output and output the time to the VCU, and the VCU outputs the time signal to the meter. This time gradually decreases when the battery thermal balance does not allow the battery management unit to output such a large power until the transition to the normal output power state. That is, in the racetrack mode, the battery discharge power is allowed to be instantaneously amplified, and the battery discharge power can be also controlled to be reduced after the vehicle is operated for a period of time at high power, so as to prevent the occurrence of a problem in battery heat balance.
In summary, according to the requirements of GB/T18385-2005 electric vehicle dynamic performance test method, the battery discharge power processing strategy provided by the embodiment of the invention can be used when the highest vehicle speed test is carried out, namely, the battery power is only allowed to be reduced but not allowed to be increased under the full throttle working condition, so as to ensure the stability of the vehicle speed.
Optionally, the control device further includes:
the power recovery module is used for stopping controlling the battery discharge power when the working condition of the vehicle changes;
the vehicle working condition change comprises the step of changing the opening rate of the accelerator pedal to exceed a preset value, the step of switching and the mode of switching.
It should be noted that, in order to avoid the power shortage caused by the lack of recovery of the power after the power is taken out in other working conditions, a recovery strategy after the battery discharge power treatment may be set, which mainly includes a recovery strategy set according to the change of the accelerator pedal and the change of the working conditions, for example, the recovery of the battery discharge power may be allowed when the accelerator pedal is released.
Specifically, the recovery condition after allowing the battery discharge power to be processed may be set as: the battery discharge power is recovered when the accelerator pedal opening is changed, and it should be noted that the range of the accelerator pedal opening change can be defined according to the specific situation, for example, 50% change is recovered; or, allowing the battery discharge power to recover when the vehicle working condition changes, wherein the vehicle working condition changes comprise gear switching or mode switching, driving and recovery switching and the like.
That is, by the above arrangement, the situation that the power is insufficient due to the fact that the power cannot be recovered after the power is taken down can be avoided.
It is worth mentioning that when the battery characteristics are different (whether the battery is a liquid cooling battery or an air cooling battery), the battery temperature fluctuation condition is different, and the control device provided by the embodiment of the invention can enable the vehicle to meet the highest vehicle speed requirement of GB T18385-2005 electric vehicle dynamic performance test method under working conditions such as high temperature and high load, meanwhile, the phenomenon that the vehicle is prone to nest can be avoided, and the driving experience is ensured. In addition, because there is a direct relationship between battery temperature and battery power, the battery power processing strategy can also be implemented by processing the battery temperature.
In the embodiment of the invention, the battery discharge power is processed, so that the test requirement can be met, and the drivability is improved; the uncomfortable driving experience caused by power fluctuation when the vehicle accelerates or climbs a slope in the running process of the vehicle in a high-temperature environment can be avoided; in addition, the temperature change rate is introduced to perform torsion limiting treatment on the over-temperature working condition in advance, so that the condition of overhigh battery temperature is avoided, and the safety of the vehicle battery is further protected.
The embodiment of the invention also provides a control device which comprises a memory, a processor and a program which is stored in the memory and can run on the processor; the processor implements the control method as described above when executing the program.
The embodiment of the invention also provides an automobile, which comprises the control device.
In the embodiment of the invention, the requirements of GB T18385-2005 electric automobile dynamic performance test method can be met aiming at different battery characteristics.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that various modifications and changes can be made without departing from the principles of the present invention, and such modifications and changes are intended to be within the scope of the present invention.

Claims (9)

1. A control method of a vehicle, characterized by comprising:
acquiring a vehicle running state of a target vehicle;
determining a target torque according to the vehicle running state;
transmitting the target torque to a motor control unit MCU so that the motor outputs the target torque;
wherein the vehicle running state includes an accelerator pedal opening, a vehicle speed, and a temperature change rate of the battery;
the determining the target torque according to the running state of the vehicle comprises the following steps:
determining the required torque of the target vehicle according to the opening of the accelerator pedal and the vehicle speed, and determining a torque limiting coefficient corresponding to the current temperature change rate of the battery of the target vehicle according to the corresponding relation between the temperature change rate of the battery and the torque limiting coefficient;
and determining the target torque according to the torque limiting coefficient and the required torque.
2. The control method according to claim 1, characterized in that the determining a target torque according to the vehicle running state includes:
obtaining the maximum allowable discharge power of the battery of the target vehicle; wherein the maximum discharge power is calculated and obtained by a battery management system BMS according to the battery working state of the target vehicle;
judging whether a first mode of the target vehicle is started or not when the opening of the accelerator pedal is larger than or equal to a preset opening value;
if the first mode is not started, controlling the battery discharge power of the target vehicle not to exceed the maximum discharge power;
and determining a target torque according to the accelerator pedal opening, the battery discharging power and the battery working state.
3. The control method according to claim 2, wherein the battery operating state includes a battery temperature, a battery cell voltage, and a state of charge SOC.
4. The control method of claim 2, wherein the first mode comprises a racetrack mode.
5. The control method according to claim 2, characterized in that the control method further comprises:
according to the corresponding relation between the maximum discharge power and time, adjusting the maximum discharge power every other preset time length;
wherein the maximum discharge power after adjustment is smaller than the maximum discharge power before adjustment.
6. The control method according to claim 2, characterized by further comprising:
stopping controlling the battery discharge power when the vehicle working condition changes;
the vehicle working condition change comprises the step of changing the opening rate of the accelerator pedal to exceed a preset value, the step of switching and the mode of switching.
7. A control device for a vehicle, comprising:
the data acquisition module is used for acquiring the vehicle running state of the target vehicle;
the torque determining module is used for determining target torque according to the running state of the vehicle;
the torque transmitting module is used for transmitting the target torque to the motor control unit MCU so that the motor outputs the target torque; wherein the vehicle running state includes an accelerator pedal opening, a vehicle speed, and a temperature change rate of the battery;
the torque determination module includes:
the power determining unit is used for determining the required torque of the target vehicle according to the opening of the accelerator pedal and the vehicle speed, and determining the torque limiting coefficient corresponding to the current temperature change rate of the battery of the target vehicle according to the corresponding relation between the temperature change rate of the battery and the torque limiting coefficient;
and the first torque unit is used for determining the target torque according to the torque limiting coefficient and the required torque.
8. A control device comprising a memory, a processor, and a program stored on the memory and executable on the processor; the control method according to any one of claims 1 to 6 is realized when the processor executes the program.
9. An automobile comprising the control device according to claim 7.
CN202010461736.4A 2020-05-27 2020-05-27 Control method and device of vehicle, control equipment and automobile Active CN113733928B (en)

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CN108162968A (en) * 2016-12-05 2018-06-15 郑州宇通客车股份有限公司 Power output control method and device, power back off control method and device
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