CN113525096A - Method for calculating available residual power of pure electric vehicle - Google Patents
Method for calculating available residual power of pure electric vehicle Download PDFInfo
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- CN113525096A CN113525096A CN202110649092.6A CN202110649092A CN113525096A CN 113525096 A CN113525096 A CN 113525096A CN 202110649092 A CN202110649092 A CN 202110649092A CN 113525096 A CN113525096 A CN 113525096A
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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
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Abstract
A method for calculating available residual power of a pure electric vehicle comprises the following steps: judging an automobile running mode, calculating available residual power in a driving mode, calculating available residual power in a feeding mode, calculating and displaying available residual power in a power-on mode, judging the running mode of the electric automobile by the vehicle controller according to an accelerator signal sent by an accelerator pedal, the current speed and the SOC of an automobile battery, and calculating the available residual power by adopting different methods in different running modes of the automobile; meanwhile, in the available residual power calculation of the automobile driving mode, the conditions that the fault exists in the whole vehicle and the fault does not exist in the whole vehicle are calculated. The design not only solves the problem that the display of the residual power is inaccurate when the motor runs at low speed, but also can accurately calculate and display the residual power of the whole automobile when the automobile has faults.
Description
Technical Field
The invention relates to power calculation of a pure electric vehicle, in particular to a method for calculating available residual power of the pure electric vehicle, which is particularly suitable for calculating the available residual power of the pure electric vehicle.
Background
According to the requirements of a new 'electric automobile instrument' standard, a vehicle instrument should indicate or display the instantaneous power output by a vehicle driving system, and should indicate or display the available residual power of the vehicle driving system at the same time, and the available residual power of the driving system should be indicated or displayed by the vehicle instrument; the second method is ((current maximum available torque of motor-current output torque) × current rotation speed of motor)/9550.
The first existing technology has the problems that the peak power is not constant when the motor is at low speed and cannot reach the peak power of the motor, and the problem of maximum power output limitation when the vehicle fails and reduces the power cannot be considered; the second technical method has a problem that the controller can output a large torque when the vehicle is stationary, but since the rotation speed is zero, the remaining power display is also zero. In order to solve the existing technical problem, a method for calculating the available residual power of the pure electric vehicle is provided, which can not only consider the inaccurate display of the residual power when the motor is at a low speed, but also consider the inaccurate current-limiting of a battery during a fault or the inaccurate currently output available residual power during the power-limiting of the whole vehicle.
Disclosure of Invention
The invention aims to solve the problem of inaccurate display of residual power when a motor is at a low speed and the power is limited when a finished automobile fails in the prior art, and provides a method for calculating the available residual power of a driving system by considering the power change of the motor at the low speed and the power limitation of the finished automobile.
In order to achieve the above purpose, the technical solution of the invention is as follows: a method for calculating available residual power of a pure electric vehicle is based on a residual power display system consisting of a vehicle control unit, a motor controller, a motor, a battery management system, a display instrument and an accelerator pedal;
the whole vehicle controller is in signal connection with the battery management system and the display instrument through a first CAN (controller area network) line;
the whole vehicle controller is in signal connection with the motor controller through a second CAN (controller area network) wire, and a motor control end of the motor controller is connected with a control signal input end of a motor;
the accelerator signal input end of the whole vehicle controller is connected with the accelerator signal output end of an accelerator pedal;
the method for calculating the available residual power comprises the following steps:
step one, judging an electric automobile operation mode:
after the electric automobile is started, the vehicle control unit, the motor controller, the motor, the battery management system, the display instrument and the accelerator pedal are electrified;
the whole vehicle controller judges the running mode of the electric vehicle according to the real-time vehicle speed, the vehicle battery SOC and an accelerator signal sent by an accelerator pedal;
when the running mode of the electric automobile is the driving mode, the step II of calculating the available residual power in the driving mode is carried out;
when the running mode of the electric automobile is a feeding mode, the step three is carried out, and the available residual power in the feeding mode is calculated;
when the running mode of the electric automobile is the power-on mode, the step four is carried out, and the available residual power in the power-on mode is calculated;
step two, calculating available residual power in a driving mode:
a1, the vehicle control unit simultaneously obtains the current maximum output power of the motor, the current maximum available torque, the current battery allowable discharge power and the current motor torque:
a. acquiring the current maximum output power of the motor and the current maximum available torque:
the motor controller queries a motor external characteristic data table according to the current rotating speed of the motor to obtain the current maximum output power and the current maximum available torque of the motor, and sends the current maximum output power and the current maximum available torque of the motor to the vehicle control unit, and the vehicle control unit obtains the current maximum output power and the current maximum available torque of the motor;
b. obtaining the current battery allowable discharge power:
the battery management system sends the current battery voltage and the current battery allowable discharge current to the vehicle control unit, and after the vehicle control unit obtains the current battery voltage and the current battery allowable discharge current, the current battery allowable discharge power is calculated according to the following formula:
the current battery allowed discharge power is equal to the current battery voltage multiplied by the current battery allowed discharge current;
c. obtaining the current motor torque:
the accelerator pedal sends an accelerator opening signal to the vehicle control unit, the vehicle control unit acquires the current accelerator opening, the motor controller sends a rotating speed signal to the vehicle control unit, and the vehicle control unit acquires the current rotating speed;
the vehicle control unit queries a given torque table according to the current rotating speed and the current accelerator opening degree to obtain corresponding given motor torque, wherein the given motor torque is the current motor torque;
a2, calculating the current maximum output power of the system:
after the vehicle control unit obtains the current allowable discharge power of the battery and the current maximum output power of the motor:
d. if the current electric automobile has no fault, calculating to obtain the current maximum output power of the system according to the following formula:
the current maximum output power of the system is Min { the current battery allowed discharge power and the current motor maximum output power };
e. if the current electric automobile has faults, calculating to obtain the current maximum output power of the system according to the following formula:
the current maximum output power of the system is Min (the current battery allowed discharge power, and the current maximum output power of the motor is multiplied by N)
N is a work limiting coefficient, and is more than or equal to 0 and less than or equal to 1;
a3, calculating available residual power of the electric automobile:
after the vehicle control unit obtains the current maximum output power of the system, the available residual power is calculated according to the following formula:
available remaining power { (current maximum available torque-current motor torque)/current maximum available torque } × (current maximum available torque) × system current maximum output power;
after the available residual power is obtained, the vehicle control unit sends the available residual power data to a display instrument;
step three, available residual power calculation in the feeding mode:
the vehicle control unit takes the peak power of the motor as available residual power and sends the available residual power to a display instrument;
step four, available residual power calculation in the power-on mode:
the vehicle control unit takes the peak power of the motor as available residual power and sends the available residual power to a display instrument;
step five, displaying:
and after the display instrument receives the available residual power sent by the vehicle control unit, displaying the available residual power.
The value method of the N of the power limiting coefficient is as follows:
dividing the faults of the electric automobile into four fault levels of a first-level fault of the whole automobile, a second-level fault of the whole automobile, a third-level fault of the whole automobile and a fourth-level fault of the whole automobile, wherein the value of the power limiting coefficient N is determined by the fault level, and the higher the fault level is, the more serious the fault is, the smaller the value of N is;
when the electric automobile has a fault, the vehicle control unit judges the fault level corresponding to the fault of the electric automobile:
f. when the fault grade corresponding to the fault existing in the electric automobile is the first-level fault of the whole automobile, the power limiting coefficient N takes a value of 1;
g. when the fault grade corresponding to the fault existing in the electric automobile is the secondary fault of the whole automobile, the power limiting coefficient N takes the value of 0.5;
h. and when the fault grade corresponding to the fault existing in the electric automobile is a finished automobile three-level fault or a finished automobile four-level fault, the power limiting coefficient N takes a value of 0.
When the fault grade corresponding to the fault of the electric automobile is a secondary fault of the whole automobile, the whole automobile controller limits the torque of the motor through the motor controller;
when the grade corresponding to the electric vehicle fault is a finished vehicle three-grade fault or a finished vehicle four-grade fault, the finished vehicle controller controls the motor to stop through the motor controller.
When the electric automobile has a primary fault, a secondary fault, a tertiary fault or a quaternary fault, the vehicle controller sends an alarm signal to the display instrument.
Step two, available residual power calculation under the driving mode: c) and in the process of obtaining the current motor torque, the vehicle control unit queries a given torque table according to the current rotating speed and the current accelerator opening degree to obtain the corresponding given motor torque, and then sends the given motor torque to the motor controller, and the motor controller controls the motor to operate under the given motor torque.
In the step one, judging the running mode of the electric automobile, the whole vehicle controller judges the running mode of the electric automobile according to the real-time speed, the SOC of the automobile battery and an accelerator signal sent by an accelerator pedal, and the step one comprises the following steps:
when the speed of the electric automobile is zero, the electric automobile is in a power-on mode;
when the speed of the electric automobile is not zero and the following conditions are met, the running mode of the electric automobile is a feeding mode; when the speed of the electric automobile is not zero and any one of the following conditions is not met, the running mode of the electric automobile is a driving mode;
i, the whole vehicle controller does not receive an accelerator signal sent by an accelerator pedal;
II, the SOC of the battery of the electric automobile is lower than a set value of the residual electric quantity;
and III, the speed of the electric automobile is greater than the set speed.
The set value of the residual electric quantity is 98 percent; the set speed is 10 km/h.
And the vehicle control unit calculates the available residual power once every 100 ms.
The external characteristic data table of the motor comprises the maximum power and the maximum available torque of the engine corresponding to the motor 3 at different rotating speeds, and the external characteristic data table of the motor is exemplified as follows:
external characteristic data table of motor
Data in the external motor characteristic data table is obtained by calibrating the motor 3, and the external motor characteristic data table is stored in the motor controller 2.
The given torque table is exemplified as follows:
given torque meter
The given torque value in the given torque meter is set according to the requirements of the vehicle dynamic performance, the economic performance and the driving feeling, and the given torque meter is stored in the vehicle controller 1.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the method for calculating the available residual power of the pure electric vehicle, the vehicle controller calculates the current maximum output power of the system according to the obtained current battery allowable discharge power and the current maximum output power of the motor, and then calculates the available residual power of the electric vehicle according to the current maximum available torque, the current motor torque and the current maximum output power of the system. Therefore, the method can accurately calculate and display the available residual power of the electric automobile under the condition that the maximum output power of the motor is not constant when the electric automobile runs at a low speed.
2. According to the method for calculating the available residual power of the pure electric vehicle, the vehicle controller judges the running mode of the electric vehicle through the signal sent by the accelerator pedal 6, the current vehicle speed and the vehicle battery SOC, judges that the electric vehicle is in the driving mode, the feeding mode or the power-on mode, and calculates the available residual power of the electric vehicle in different modes according to different running modes of the electric vehicle, so that the problem that the residual power displayed when the electric vehicle is in the feeding mode is inaccurate or the residual power displayed is zero when the electric vehicle does not start to run after being powered on in the prior art is solved. Therefore, the method calculates the available residual power of the electric automobile in different modes according to different modes of the electric automobile, so that the available residual power can be displayed more accurately.
3. The method for calculating the available residual power of the pure electric vehicle considers the influence of the special state of the vehicle caused by fault shutdown or limited work operation on the available residual power, determines the value of the limited work coefficient N according to the whole vehicle fault level of the electric vehicle under the condition that the vehicle has a fault, and substitutes the value of the limited work coefficient N into the calculation, so that the available residual power of the electric vehicle can be accurately calculated and displayed under the special condition that the vehicle has the fault. Therefore, the work limit coefficient N is substituted for calculation in the method, so that the available residual power of the electric automobile can be accurately calculated and displayed under the special condition of vehicle failure.
Drawings
Fig. 1 is a schematic diagram of the available residual power of the motor.
Fig. 2 is a schematic diagram of the hardware architecture of the present invention.
Fig. 3 is a flow chart of the remaining power calculation.
Fig. 4 is a flowchart of the calculation of the remaining power available in the driving mode.
In the figure: the system comprises a vehicle control unit 1, a motor controller 2, a motor 3, a battery management system 4, a display instrument 5 and an accelerator pedal 6.
Detailed Description
The present invention will be described in further detail with reference to the following description and embodiments in conjunction with the accompanying drawings.
Referring to fig. 1 to 4, the method for calculating the available residual power of the pure electric vehicle is based on a residual power display system composed of a vehicle control unit 1, a motor controller 2, a motor 3, a battery management system 4, a display instrument 5 and an accelerator pedal 6;
the vehicle control unit 1 is in signal connection with the battery management system 4 and the display instrument 5 through a first CAN line;
the vehicle control unit 1 is in signal connection with the motor controller 2 through a second CAN (controller area network) line, and a motor control end of the motor controller 2 is connected with a control signal input end of the motor 3;
an accelerator signal input end of the whole vehicle controller 1 is connected with an accelerator signal output end of an accelerator pedal 6;
the method for calculating the available residual power comprises the following steps:
step one, judging an electric automobile operation mode:
after the electric automobile is started, the vehicle control unit 1, the motor controller 2, the motor 3, the battery management system 4, the display instrument 5 and the accelerator pedal 6 are powered on;
the vehicle control unit 1 judges the running mode of the electric vehicle according to the real-time vehicle speed, the vehicle battery SOC and an accelerator signal sent by an accelerator pedal 6;
when the running mode of the electric automobile is the driving mode, the step II of calculating the available residual power in the driving mode is carried out;
when the running mode of the electric automobile is a feeding mode, the step three is carried out, and the available residual power in the feeding mode is calculated;
when the running mode of the electric automobile is the power-on mode, the step four is carried out, and the available residual power in the power-on mode is calculated;
step two, calculating available residual power in a driving mode:
a1, the vehicle control unit 1 simultaneously obtains the current maximum output power of the motor, the current maximum available torque, the current battery allowable discharge power and the current motor torque:
a. acquiring the current maximum output power of the motor and the current maximum available torque:
the motor controller 2 queries a motor external characteristic data table according to the current rotating speed of the motor to obtain the current maximum output power and the current maximum available torque of the motor, and sends the current maximum output power and the current maximum available torque of the motor to the vehicle control unit 1, and the vehicle control unit 1 obtains the current maximum output power and the current maximum available torque of the motor;
b. obtaining the current battery allowable discharge power:
the battery management system 4 sends the current battery voltage and the current battery allowable discharge current to the vehicle control unit 1, and after the vehicle control unit 1 obtains the current battery voltage and the current battery allowable discharge current, the current battery allowable discharge power is calculated according to the following formula:
the current battery allowed discharge power is equal to the current battery voltage multiplied by the current battery allowed discharge current;
c. obtaining the current motor torque:
the accelerator pedal 6 sends an accelerator opening signal to the vehicle control unit 1, the vehicle control unit 1 acquires the current accelerator opening, the motor controller 2 sends a rotating speed signal to the vehicle control unit 1, and the vehicle control unit 1 acquires the current rotating speed;
the vehicle control unit 1 queries a given torque table according to the current rotating speed and the current accelerator opening degree to obtain a corresponding given motor torque, wherein the given motor torque is the current motor torque;
a2, calculating the current maximum output power of the system:
after the vehicle control unit 1 obtains the current battery allowable discharge power and the current maximum output power of the motor:
d. if the current electric automobile has no fault, calculating to obtain the current maximum output power of the system according to the following formula:
the current maximum output power of the system is Min { the current battery allowed discharge power and the current motor maximum output power };
e. if the current electric automobile has faults, calculating to obtain the current maximum output power of the system according to the following formula:
the current maximum output power of the system is Min (the current battery allowed discharge power, and the current maximum output power of the motor is multiplied by N)
N is a work limiting coefficient, and is more than or equal to 0 and less than or equal to 1;
a3, calculating available residual power of the electric automobile:
after obtaining the current maximum output power of the system, the vehicle control unit 1 calculates the available remaining power according to the following formula:
available remaining power { (current maximum available torque-current motor torque)/current maximum available torque } × (current maximum available torque) × system current maximum output power;
after the available residual power is obtained, the vehicle control unit 1 sends the available residual power data to the display instrument 5;
step three, available residual power calculation in the feeding mode:
the vehicle control unit 1 takes the peak power of the motor 3 as available residual power and sends the available residual power to the display instrument 5;
step four, available residual power calculation in the power-on mode:
the vehicle control unit 1 takes the peak power of the motor 3 as available residual power and sends the available residual power to the display instrument 5;
step five, displaying:
and after receiving the available residual power sent by the vehicle control unit 1, the display instrument 5 displays the available residual power.
The value method of the N of the power limiting coefficient is as follows:
dividing the faults of the electric automobile into four fault levels of a first-level fault of the whole automobile, a second-level fault of the whole automobile, a third-level fault of the whole automobile and a fourth-level fault of the whole automobile, wherein the value of the power limiting coefficient N is determined by the fault level, and the higher the fault level is, the more serious the fault is, the smaller the value of N is;
when the electric automobile has a fault, the vehicle control unit 1 judges the fault level corresponding to the fault of the electric automobile:
f. when the fault grade corresponding to the fault existing in the electric automobile is the first-level fault of the whole automobile, the power limiting coefficient N takes a value of 1;
g. when the fault grade corresponding to the fault existing in the electric automobile is the secondary fault of the whole automobile, the power limiting coefficient N takes the value of 0.5;
h. and when the fault grade corresponding to the fault existing in the electric automobile is a finished automobile three-level fault or a finished automobile four-level fault, the power limiting coefficient N takes a value of 0.
When the fault grade corresponding to the fault existing in the electric automobile is a secondary fault of the whole automobile, the whole automobile controller 1 limits the torque of the motor 3 through the motor controller 2;
when the grade corresponding to the electric vehicle fault is a finished vehicle three-grade fault or a finished vehicle four-grade fault, the finished vehicle controller 1 controls the motor 3 to stop through the motor controller 2.
When the electric automobile has a primary fault, a secondary fault, a tertiary fault or a quaternary fault, the vehicle controller 1 sends an alarm signal to the display instrument 5.
Step two, available residual power calculation under the driving mode: c) in the process of obtaining the current motor torque, the vehicle control unit 1 queries a given torque table according to the current rotating speed and the current accelerator opening degree to obtain the corresponding given motor torque, and then sends the given motor torque to the motor controller 2, and the motor controller 2 controls the motor 3 to operate under the given motor torque.
In the step one, judging the running mode of the electric automobile, the whole vehicle controller 1 judges the running mode of the electric automobile according to the real-time speed, the SOC of the automobile battery and the accelerator signal sent by the accelerator pedal 6, and comprises the following steps:
when the speed of the electric automobile is zero, the electric automobile is in a power-on mode;
when the speed of the electric automobile is not zero and the following conditions are met, the running mode of the electric automobile is a feeding mode; when the speed of the electric automobile is not zero and any one of the following conditions is not met, the running mode of the electric automobile is a driving mode;
i, the vehicle control unit 1 does not receive an accelerator signal sent by an accelerator pedal 6;
II, the SOC of the battery of the electric automobile is lower than a set value of the residual electric quantity;
and III, the speed of the electric automobile is greater than the set speed.
The set value of the residual electric quantity is 98 percent; the set speed is 10 km/h.
The vehicle control unit 1 calculates the available remaining power once every 100 ms.
The external characteristic data table of the motor comprises a table of maximum power and maximum available torque of the engine corresponding to the motor 3 at different rotating speeds, and the external characteristic data table of the motor is exemplified as follows:
external characteristic data table of motor
The data in the external characteristic data table of the motor is obtained by calibrating the motor 3, and the external characteristic data table of the motor is stored in the motor controller 2.
The given torque table comprises given torque values corresponding to different rotation speeds and different accelerator opening degrees of the motor 3, and the given torque table is exemplified as follows:
given torque meter
The given torque value in the given torque meter is set according to the requirements of the vehicle dynamic performance, the economic performance and the driving feeling, and the given torque meter is stored in the vehicle controller 1.
The principle of the invention is illustrated as follows:
the SOC is a State of Charge of the automobile battery, namely State of Charge, SOC for short, and is a ratio of the remaining capacity to the battery capacity, and is used for reflecting the remaining capacity of the battery.
When the electric automobile operates in the feeding mode, the motor 3 is in a power generation state.
The peak power of the motor 3 is the maximum output power that the motor 3 can reach in a short time.
The electric automobile can have various faults, the faults of the electric automobiles of different types are divided into four fault levels of a primary fault of the whole automobile, a secondary fault of the whole automobile, a tertiary fault of the whole automobile and a quaternary fault of the whole automobile according to the severity, and each fault corresponds to one fault level;
the value of the power limiting coefficient N is determined by the fault grade, the higher the fault grade is, the more serious the fault is, and the smaller the value of N is;
the different electric vehicle faults and fault levels corresponding to the faults are as follows:
example 1:
a method for calculating available residual power of a pure electric vehicle is based on a residual power display system consisting of a vehicle control unit 1, a motor controller 2, a motor 3, a battery management system 4, a display instrument 5 and an accelerator pedal 6;
the vehicle control unit 1 is in signal connection with the battery management system 4 and the display instrument 5 through a first CAN line;
the vehicle control unit 1 is in signal connection with the motor controller 2 through a second CAN (controller area network) line, and a motor control end of the motor controller 2 is connected with a control signal input end of the motor 3;
an accelerator signal input end of the whole vehicle controller 1 is connected with an accelerator signal output end of an accelerator pedal 6;
the method for calculating the available residual power comprises the following steps:
step one, judging an electric automobile operation mode:
after the electric automobile is started, the vehicle control unit 1, the motor controller 2, the motor 3, the battery management system 4, the display instrument 5 and the accelerator pedal 6 are powered on;
the vehicle control unit 1 judges the running mode of the electric vehicle according to an accelerator signal, a real-time vehicle speed and the vehicle battery SOC sent by an accelerator pedal 6;
when the running mode of the electric automobile is the driving mode, the step II of calculating the available residual power in the driving mode is carried out;
when the running mode of the electric automobile is a feeding mode, the step three is carried out, and the available residual power in the feeding mode is calculated;
when the running mode of the electric automobile is the power-on mode, the step four is carried out, and the available residual power in the power-on mode is calculated;
step two, calculating available residual power in a driving mode:
a1, the vehicle control unit 1 simultaneously obtains the current maximum output power of the motor, the current maximum available torque, the current battery allowable discharge power and the current motor torque:
a. acquiring the current maximum output power of the motor and the current maximum available torque:
the motor controller 2 queries a motor external characteristic data table according to the current rotating speed of the motor to obtain the current maximum output power and the current maximum available torque of the motor, and sends the current maximum output power and the current maximum available torque of the motor to the vehicle control unit 1, and the vehicle control unit 1 obtains the current maximum output power and the current maximum available torque of the motor;
b. obtaining the current battery allowable discharge power:
the battery management system 4 sends the current battery voltage and the current battery allowable discharge current to the vehicle control unit 1, and after the vehicle control unit 1 obtains the current battery voltage and the current battery allowable discharge current, the current battery allowable discharge power is calculated according to the following formula:
the current battery allowed discharge power is equal to the current battery voltage multiplied by the current battery allowed discharge current;
c. obtaining the current motor torque:
the accelerator pedal 6 sends an accelerator opening signal to the vehicle control unit 1, the vehicle control unit 1 acquires the current accelerator opening, the motor controller 2 sends a rotating speed signal to the vehicle control unit 1, and the vehicle control unit 1 acquires the current rotating speed;
the vehicle control unit 1 queries a given torque table according to the current rotating speed and the current accelerator opening degree to obtain a corresponding given motor torque, wherein the given motor torque is the current motor torque;
a2, calculating the current maximum output power of the system:
after the vehicle control unit 1 obtains the current battery allowable discharge power and the current maximum output power of the motor:
d. if the current electric automobile has no fault, calculating to obtain the current maximum output power of the system according to the following formula:
the current maximum output power of the system is Min { the current battery allowed discharge power and the current motor maximum output power };
e. if the current electric automobile has faults, calculating to obtain the current maximum output power of the system according to the following formula:
the current maximum output power of the system is Min (the current battery allowed discharge power, and the current maximum output power of the motor is multiplied by N)
N is a work limiting coefficient, and is more than or equal to 0 and less than or equal to 1;
a3, calculating available residual power of the electric automobile:
after obtaining the current maximum output power of the system, the vehicle control unit 1 calculates the available remaining power according to the following formula:
available remaining power { (current maximum available torque-current motor torque)/current maximum available torque } × (current maximum available torque) × system current maximum output power;
after the available residual power is obtained, the vehicle control unit 1 sends the available residual power data to a display instrument (5);
step three, available residual power calculation in the feeding mode:
the vehicle control unit 1 takes the peak power of the motor 3 as available residual power and sends the available residual power to the display instrument 5;
step four, available residual power calculation in the power-on mode:
the vehicle control unit 1 takes the peak power of the motor 3 as available residual power and sends the available residual power to the display instrument 5;
step five, displaying:
after receiving the available residual power sent by the vehicle control unit 1, the display instrument 5 displays the available residual power;
the value method of the N of the power limiting coefficient is as follows:
dividing the faults of the electric automobile into four fault levels of a first-level fault of the whole automobile, a second-level fault of the whole automobile, a third-level fault of the whole automobile and a fourth-level fault of the whole automobile, wherein the value of the power limiting coefficient N is determined by the fault level, and the higher the fault level is, the more serious the fault is, the smaller the value of N is;
when the electric automobile has a fault, the vehicle control unit 1 judges the fault level corresponding to the fault of the electric automobile:
f. when the fault grade corresponding to the fault existing in the electric automobile is the first-level fault of the whole automobile, the power limiting coefficient N takes a value of 1;
g. when the fault grade corresponding to the fault existing in the electric automobile is the secondary fault of the whole automobile, the power limiting coefficient N takes the value of 0.5;
h. when the fault level corresponding to the fault of the electric automobile is a finished automobile three-level fault or a finished automobile four-level fault, the power limiting coefficient N takes a value of 0;
when the fault grade corresponding to the fault existing in the electric automobile is a secondary fault of the whole automobile, the whole automobile controller 1 limits the torque of the motor 3 through the motor controller 2;
when the grade corresponding to the electric vehicle fault is a finished vehicle three-grade fault or a finished vehicle four-grade fault, the finished vehicle controller 1 controls the motor 3 to stop through the motor controller 2;
when the electric automobile has a primary fault, a secondary fault, a tertiary fault or a quaternary fault, the vehicle controller 1 sends an alarm signal to the display instrument 5.
Example 2:
example 2 is substantially the same as example 1 except that:
step two, available residual power calculation under the driving mode: c) in the process of obtaining the current motor torque, the vehicle control unit 1 queries a given torque table according to the current rotating speed and the current accelerator opening degree to obtain the corresponding given motor torque, and then sends the given motor torque to the motor controller 2, and the motor controller 2 controls the motor 3 to operate under the given motor torque.
In the step one, judging the running mode of the electric automobile, the vehicle control unit 1 judges the running mode of the electric automobile according to an accelerator signal, a real-time speed and an automobile battery SOC sent by an accelerator pedal 6:
when the speed of the electric automobile is zero, the electric automobile is in a power-on mode;
when the speed of the electric automobile is not zero and the following conditions are met, the running mode of the electric automobile is a feeding mode; when the speed of the electric automobile is not zero and any one of the following conditions is not met, the running mode of the electric automobile is a driving mode;
i, the vehicle control unit 1 does not receive an accelerator signal sent by an accelerator pedal 6;
II, the SOC of the battery of the electric automobile is lower than a set value of the residual electric quantity;
III, the speed of the electric automobile is greater than a set speed;
the set value of the residual electric quantity is 98 percent; the set speed is 10 km/h;
the vehicle control unit 1 calculates available residual power once every 100 ms;
the external characteristic data table of the motor comprises a table of maximum power and maximum available torque of the engine corresponding to the motor 3 at different rotating speeds, and the external characteristic data table of the motor is exemplified as follows:
external characteristic data table of motor
The data in the external characteristic data table of the motor is obtained by calibrating the motor 3, and the external characteristic data table of the motor is stored in the motor controller 2.
The given torque table comprises given torque values corresponding to different rotation speeds and different accelerator opening degrees of the motor 3, and the given torque table is exemplified as follows:
given torque meter
The given torque values corresponding to different rotating speeds and different accelerator opening degrees of the motor 3 are set according to the requirements of the power performance, the economic performance and the driving feeling of the whole vehicle, and the given torque meter is stored in the whole vehicle controller 1.
Example 3:
after the electric automobile is ignited and started, in the driving process, the vehicle controller 1 receives an accelerator signal sent by an accelerator pedal 6, the speed of the electric automobile is not zero, at the moment, the automobile is in a driving mode,
at this time, the motor controller 2 queries the motor external characteristic data table according to the current rotating speed 2000r/min of the motor to obtain the current maximum available torque of 320N · m and the current maximum output power of the motor of 67KW, and sends the current maximum available torque of 320N · m and the current maximum output power of the motor of 67KW to the vehicle control unit 1;
the motor external characteristic data table is exemplified as follows:
external characteristic data table of motor
Meanwhile, the battery management system 4 sends the current battery allowable discharge current of 240A and the current battery voltage of 540V to the vehicle control unit 1, and the vehicle control unit 1 performs the following steps: the current battery allowable discharge power is current battery voltage × current battery allowable discharge current, and the current battery allowable discharge power can be calculated to be 540V × 240A — 130 KW;
meanwhile, the vehicle control unit 1 receives that the current rotating speed of the motor sent by the motor controller 2 is 2000r/min, the accelerator pedal 6 sends the current accelerator opening of 80% to the vehicle control unit 1, and the vehicle control unit 1 queries a given torque table according to the current rotating speed of 2000r/min and the accelerator opening of 80% to obtain the current motor torque of 288 N.m;
the given torque table is exemplified as follows:
given torque meter
If the current vehicle has no fault, the vehicle control unit 1 is according to: the current maximum output power of the system is Min (the current battery allowed discharge power and the current motor maximum output power),
the current maximum output power of the system can be calculated to be 67 KW;
If the current vehicle has a main circuit reverse differential pressure fault, because the main circuit reverse differential pressure fault is a vehicle secondary fault, the power limiting coefficient N is 0.5, and the vehicle control unit 1 is according to the following steps: the current maximum output power of the system is Min (the current battery allowed discharge power, the current motor maximum output power multiplied by N),
the current maximum output power of the system can be calculated to be 33.5 KW;
When the speed of the electric automobile is not zero and the following conditions are met, the vehicle control unit 1 judges that the running mode of the electric automobile is a feeding mode;
1) the vehicle control unit 1 does not receive an accelerator signal sent by the accelerator pedal 6;
2) the SOC of the battery of the electric automobile is lower than 98 percent;
3) and the speed of the electric automobile is more than 10 km/h.
At this time, the vehicle control unit 1 sends the peak power of the motor 3, that is, the maximum value of the output power of the motor 3 is 120KW to the display instrument 5, and the display instrument 5 displays that the available residual power is 120 KW.
After the electric automobile is started and powered on, when the whole automobile is in a static state, the running mode of the electric automobile is the power-on mode, the vehicle controller 1 sends the peak power of the motor 3, namely the maximum value of the output power of the motor 3 is 120KW to the display instrument 5, and the display instrument 5 displays that the available residual power is 120 kW.
Claims (10)
1. A method for calculating available residual power of a pure electric vehicle is characterized by comprising the following steps:
the method is based on a residual power display system consisting of a vehicle control unit (1), a motor controller (2), a motor (3), a battery management system (4), a display instrument (5) and an accelerator pedal (6);
the vehicle control unit (1) is in signal connection with the battery management system (4) and the display instrument (5) through a first CAN line;
the vehicle control unit (1) is in signal connection with the motor controller (2) through a second CAN (controller area network) line, and a motor control end of the motor controller (2) is connected with a control signal input end of the motor (3);
the accelerator signal input end of the whole vehicle controller (1) is connected with the accelerator signal output end of an accelerator pedal (6);
the method for calculating the available residual power comprises the following steps:
step one, judging an electric automobile operation mode:
after the electric automobile is started, the vehicle control unit (1), the motor controller (2), the motor (3), the battery management system (4), the display instrument (5) and the accelerator pedal (6) are powered on;
the whole vehicle controller (1) judges the running mode of the electric vehicle according to the real-time vehicle speed, the vehicle battery SOC and an accelerator signal sent by an accelerator pedal (6);
when the running mode of the electric automobile is the driving mode, the step II of calculating the available residual power in the driving mode is carried out;
when the running mode of the electric automobile is a feeding mode, the step three is carried out, and the available residual power in the feeding mode is calculated;
when the running mode of the electric automobile is the power-on mode, the step four is carried out, and the available residual power in the power-on mode is calculated;
step two, calculating available residual power in a driving mode:
a1, the vehicle control unit (1) simultaneously acquires the current maximum output power of the motor, the current maximum available torque, the current battery allowable discharge power and the current motor torque:
a. acquiring the current maximum output power of the motor and the current maximum available torque:
the motor controller (2) queries a motor external characteristic data table according to the current rotating speed of the motor to obtain the current maximum output power and the current maximum available torque of the motor, and sends the current maximum output power and the current maximum available torque of the motor to the vehicle control unit (1), and the vehicle control unit (1) obtains the current maximum output power and the current maximum available torque of the motor;
b. obtaining the current battery allowable discharge power:
the battery management system (4) sends the current battery voltage and the current battery allowable discharge current to the vehicle control unit (1), and after the vehicle control unit (1) obtains the current battery voltage and the current battery allowable discharge current, the current battery allowable discharge power is calculated according to the following formula:
the current battery allowed discharge power is equal to the current battery voltage multiplied by the current battery allowed discharge current;
c. obtaining the current motor torque:
the accelerator pedal (6) sends an accelerator opening degree signal to the vehicle control unit (1), the vehicle control unit (1) acquires the current accelerator opening degree, the motor controller (2) sends a rotating speed signal to the vehicle control unit (1), and the vehicle control unit (1) acquires the current rotating speed;
the vehicle control unit (1) queries a given torque table according to the current rotating speed and the current accelerator opening degree to obtain corresponding given motor torque, wherein the given motor torque is the current motor torque;
a2, calculating the current maximum output power of the system:
after the vehicle control unit (1) obtains the current battery allowable discharge power and the current motor maximum output power:
d. if the current electric automobile has no fault, calculating to obtain the current maximum output power of the system according to the following formula:
the current maximum output power of the system is Min { the current battery allowed discharge power and the current motor maximum output power };
e. if the current electric automobile has faults, calculating to obtain the current maximum output power of the system according to the following formula:
the current maximum output power of the system is Min (the current battery allowed discharge power, and the current maximum output power of the motor is multiplied by N)
N is a work limiting coefficient, and is more than or equal to 0 and less than or equal to 1;
a3, calculating available residual power of the electric automobile:
after the vehicle control unit (1) obtains the current maximum output power of the system, the available residual power is calculated according to the following formula:
available remaining power { (current maximum available torque-current motor torque)/current maximum available torque } × (current maximum available torque) × system current maximum output power;
after the available residual power is obtained, the vehicle control unit (1) sends the available residual power data to a display instrument (5);
step three, available residual power calculation in the feeding mode:
the vehicle control unit (1) takes the peak power of the motor (3) as available residual power and sends the available residual power to the display instrument (5);
step four, available residual power calculation in the power-on mode:
the vehicle control unit (1) takes the peak power of the motor (3) as available residual power and sends the available residual power to the display instrument (5);
step five, displaying:
and after the display instrument (5) receives the available residual power sent by the vehicle control unit (1), the available residual power is displayed.
2. The method for calculating the available residual power of the pure electric vehicle according to claim 1, characterized in that:
the value method of the N of the power limiting coefficient is as follows:
dividing the faults of the electric automobile into four fault levels of a first-level fault of the whole automobile, a second-level fault of the whole automobile, a third-level fault of the whole automobile and a fourth-level fault of the whole automobile, wherein the value of the power limiting coefficient N is determined by the fault level, and the higher the fault level is, the more serious the fault is, the smaller the value of N is;
when the electric automobile has a fault, the vehicle control unit (1) judges the fault level corresponding to the fault of the electric automobile:
f. when the fault grade corresponding to the fault existing in the electric automobile is the first-level fault of the whole automobile, the power limiting coefficient N takes a value of 1;
g. when the fault grade corresponding to the fault existing in the electric automobile is the secondary fault of the whole automobile, the power limiting coefficient N takes the value of 0.5;
h. and when the fault grade corresponding to the fault existing in the electric automobile is a finished automobile three-level fault or a finished automobile four-level fault, the power limiting coefficient N takes a value of 0.
3. The method for calculating the available residual power of the pure electric vehicle according to claim 2, characterized in that:
when the fault grade corresponding to the fault existing in the electric automobile is a secondary fault of the whole automobile, the whole automobile controller (1) limits the torque of the motor (3) through the motor controller (2);
when the grade corresponding to the electric vehicle fault is a finished vehicle three-grade fault or a finished vehicle four-grade fault, the finished vehicle controller (1) controls the motor (3) to stop through the motor controller (2).
4. The method for calculating the available residual power of the pure electric vehicle according to claim 3, characterized in that:
when the electric automobile has a primary fault, a secondary fault, a tertiary fault or a quaternary fault, the vehicle controller (1) sends an alarm signal to the display instrument (5).
5. The method for calculating the available residual power of the pure electric vehicle according to any one of claims 1 to 4, characterized in that:
step two, available residual power calculation under the driving mode: c) in the process of obtaining the current motor torque, the vehicle control unit (1) queries a given torque table according to the current rotating speed and the current accelerator opening degree to obtain the corresponding given motor torque, the given motor torque is sent to the motor controller (2), and the motor controller (2) controls the motor (3) to operate under the given motor torque.
6. The method for calculating the available residual power of the pure electric vehicle according to claim 5, characterized in that:
in the step one, judging the running mode of the electric automobile, the whole vehicle controller (1) judges the running mode of the electric automobile according to the real-time speed, the SOC of the automobile battery and the throttle signal sent by the throttle pedal (6) and comprises the following steps:
when the speed of the electric automobile is zero, the electric automobile is in a power-on mode;
when the speed of the electric automobile is not zero and the following conditions are met, the running mode of the electric automobile is a feeding mode, and when the speed of the electric automobile is not zero and any one of the following conditions is not met, the running mode of the electric automobile is a driving mode;
i, the whole vehicle controller (1) does not receive an accelerator signal sent by an accelerator pedal (6);
II, the SOC of the battery of the electric automobile is lower than a set value of the residual electric quantity;
and III, the speed of the electric automobile is greater than the set speed.
7. The method for calculating the available residual power of the pure electric vehicle according to claim 6, characterized in that:
the set value of the residual electric quantity is 98 percent; the set speed is 10 km/h.
8. The method for calculating the available residual power of the pure electric vehicle according to claim 7, characterized in that:
the vehicle control unit (1) calculates available residual power once every 100 ms.
9. The method for calculating the available residual power of the pure electric vehicle according to claim 8, wherein the method comprises the following steps:
the external characteristic data table of the motor comprises the maximum power and the maximum available torque of the engine corresponding to the motor (3) under different rotating speeds, and the external characteristic data table of the motor is exemplified as follows:
external characteristic data table of motor
Data in the external characteristic data table of the motor are obtained by calibrating the motor (3), and the external characteristic data table of the motor is stored in the motor controller (2).
10. The method for calculating the available residual power of the pure electric vehicle according to claim 9, wherein the method comprises the following steps:
the given torque table is exemplified as follows:
given torque meter
The given torque value in the given torque meter is set according to the requirements of the vehicle dynamic performance, the economic performance and the driving feeling, and the given torque meter is stored in the vehicle controller (1).
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| CN113910912A (en) * | 2021-11-16 | 2022-01-11 | 重庆金康赛力斯新能源汽车设计院有限公司 | Display method of power of electric automobile and vehicle-mounted electronic equipment |
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