CN112448636B - Method for controlling acceleration of electric vehicle - Google Patents
Method for controlling acceleration of electric vehicle Download PDFInfo
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- CN112448636B CN112448636B CN202011414606.1A CN202011414606A CN112448636B CN 112448636 B CN112448636 B CN 112448636B CN 202011414606 A CN202011414606 A CN 202011414606A CN 112448636 B CN112448636 B CN 112448636B
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- 238000000034 method Methods 0.000 title claims abstract description 29
- 238000004364 calculation method Methods 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/14—Estimation or adaptation of machine parameters, e.g. flux, current or voltage
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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
- B60L15/28—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 without contact making and breaking, e.g. using a transductor
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/0003—Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/34—Arrangements for starting
-
- 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
- B60L2240/14—Acceleration
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- 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)
- Electric Propulsion And Braking For Vehicles (AREA)
Abstract
The invention discloses a method for controlling the acceleration of an electric vehicle, which comprises the following steps: acquiring the highest speed limit of the electric vehicle, and setting an initial expected acceleration according to the highest speed limit of the electric vehicle; acquiring a target rotating speed, acquiring an actual rotating speed in a fixed time period, calculating an actual acceleration, and adjusting an expected acceleration according to the actual rotating speed; calculating a difference value between the target rotating speed and the actual rotating speed, and performing proportional integral operation to obtain a q-axis current given value; obtaining a q-axis current actual value, and obtaining a difference value of the q-axis current by making a difference between a q-axis current set value and the q-axis current actual value; limiting the amplitude of the difference value of the q-axis current according to the actual acceleration and the expected acceleration to obtain the amplitude limit value of the difference value of the q-axis current; the method realizes the control of the acceleration, so that the electric vehicle has uniform torque output in the acceleration process.
Description
Technical Field
The invention relates to the technical field of electric vehicle control, in particular to a method for controlling the acceleration of an electric vehicle.
Background
The electric vehicle is an important daily tool for riding instead of walk, and meets the requirement of people on short-distance running. It has the advantages of environmental protection, convenient use and the like.
Most electric vehicle manufacturers in the market neglect to improve the driving feeling of the electric vehicle, many electric vehicles accelerate quickly when starting, strong 'back pushing feeling' is brought to drivers, the feeling of poor vehicle control performance is brought, and even potential safety hazards are caused; and the driving feeling is affected by the weakness when the vehicle accelerates from a medium speed to a high speed. This is mainly caused by the uneven distribution of torque output, and directly corresponds to the control of q-axis current in a vector control system. At present, in a traditional brushless direct current motor vector control system for an electric vehicle, a q-axis current value is directly output for control after rotating speed conversion calculation, so that only control of a single speed loop can be realized, and acceleration cannot be controlled.
The invention further controls the output q-axis current value according to the acceleration and the expected acceleration so as to realize the control of the acceleration, so that the electric vehicle has uniform torque output in the acceleration process.
Disclosure of Invention
The invention aims to provide a method for controlling the acceleration of an electric vehicle, which further adjusts the current value of an output q-axis by adopting a root acceleration and an expected acceleration so as to solve the problem of uneven torque output distribution in the acceleration process of the electric vehicle in the prior art.
The invention provides a method for controlling the acceleration of an electric vehicle, which comprises the following steps:
step 1: acquiring the highest speed limit of the electric vehicle, and setting an initial expected acceleration according to the highest speed limit of the electric vehicle;
step 2: acquiring an actual rotating speed, calculating an actual acceleration, and adjusting an initial expected acceleration of which the expected acceleration is 1-2 times when the actual rotating speed is greater than or equal to a threshold;
and step 3: acquiring a target rotating speed from a rotating handle of the electric vehicle, calculating a difference value between the target rotating speed and an actual rotating speed, and performing proportional-integral operation on the difference value to obtain a q-axis current given value;
and 4, step 4: obtaining a q-axis current actual value, and obtaining a difference value of the q-axis current by making a difference between a q-axis current set value and the q-axis current actual value;
and 5: multiplying the ratio of the expected acceleration to the actual acceleration by the difference of the q-axis current to obtain a difference amplitude limit value of the q-axis current;
step 6: and the difference amplitude limit value of the q-axis current is subjected to proportional-integral operation to obtain the voltage of the q axis, and the PWM duty ratio in the motor vector control is controlled according to the voltage of the q axis, so that the acceleration process of the electric vehicle is completed.
Further, the specific setting method for setting the initial expected acceleration in the step 1 includes:
when the highest speed limit of the electric vehicle is 25km/h, the set range of the initial expected acceleration is 10-30 r/s 2 ；
When the highest speed limit of the electric vehicle is 50km/h, the set range of the initial expected acceleration is 20-50 r/s 2 ；
When the highest speed limit of the electric vehicle is more than 50km/h, the setting range of the initial expected acceleration is 25 to E80r/s 2 。
Further, the specific method for adjusting the expected acceleration according to the actual speed in step 2 is as follows:
when the highest speed limit of the electric vehicle is 25km/h and the actual speed is less than 5km/h, the expected acceleration is equal to the initial expected acceleration;
when the highest speed limit of the electric vehicle is 25km/h and the actual speed is not less than 5km/h, adjusting the expected acceleration to be 1-2 times of the initial expected acceleration;
when the highest speed limit of the electric vehicle is not less than 50km/h and the actual speed is less than 10km/h, the expected acceleration is equal to the initial expected acceleration;
and when the highest speed limit of the electric vehicle is not less than 50km/h and the actual speed is not less than 10km/h, adjusting the expected acceleration to be 1-2 times of the initial expected acceleration.
Further, the specific calculation method for obtaining the difference amplitude limit value of the q-axis current in the step 5 is as follows:
wherein, Δ i q Is the difference amplitude limit value of the q-axis current, Δ i q Is the difference of the q-axis current, a r For actual acceleration, a c Is the desired acceleration.
The invention has the beneficial effects that:
1. The initial expected acceleration is set according to the highest speed limit of the electric vehicle so as to meet the acceleration requirements of national standard electric vehicles with speed limit of 25km/h, portable electric motorcycles with speed limit of 50km/h and electric motorcycles with speed limit of more than 50 km/h.
2. The expected acceleration is adjusted according to the actual speed, so that the electric vehicle can obtain smooth starting acceleration and can also quickly accelerate.
3. The method for limiting the amplitude by adopting the difference value of the q-axis current can avoid the problem of over-quick acceleration when the electric vehicle starts, and can compensate the torque and improve the problem of weak acceleration when the electric vehicle accelerates from a medium speed to a high speed.
Drawings
The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:
fig. 1 is a general flowchart illustrating a method of controlling acceleration of an electric vehicle according to the present invention.
Fig. 2 is a system diagram illustrating a q-axis current control method in conventional vector control.
FIG. 3 is a system diagram illustrating a method for improving q-axis current control in vector control according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a method for controlling the acceleration of an electric vehicle, which comprises the following steps as shown in figure 1:
step S1: acquiring the highest speed limit of the electric vehicle, and setting an initial expected acceleration according to the highest speed limit of the electric vehicle;
the specific setting method for setting the initial expected acceleration comprises the following steps:
when the highest speed limit of the electric vehicle is 25km/h, the initial expected acceleration is 10-30 r/s 2 ；
When the highest speed limit of the electric vehicle is 50km/h, the initial expected acceleration is 20-50 r/s 2 ；
When the highest speed limit of the electric vehicle is more than 50km/h, the initial expected acceleration is 25-80 r/s 2 。
Step S2: acquiring an actual rotating speed, calculating an actual acceleration, and adjusting the expected acceleration to be 1-2 times of an initial expected acceleration when the actual rotating speed is greater than or equal to a threshold value;
the specific method for adjusting the expected acceleration according to the actual speed is as follows:
when the highest speed limit of the electric vehicle is 25km/h and the actual speed is less than 5km/h, the expected acceleration is equal to the initial expected acceleration;
when the highest speed limit of the electric vehicle is 25km/h and the actual speed is not less than 5km/h, adjusting the expected acceleration to be 1-2 times of the initial expected acceleration;
when the highest speed limit of the electric vehicle is not less than 50km/h and the actual speed is less than 10km/h, the expected acceleration is equal to the initial expected acceleration;
And when the highest speed limit of the electric vehicle is not less than 50km/h and the actual speed is not less than 10km/h, adjusting the expected acceleration to be 1-2 times of the initial expected acceleration.
Step S3: acquiring a target rotating speed from a rotating handle of the electric vehicle, calculating a difference value between the target rotating speed and an actual rotating speed, and performing proportional-integral operation on the difference value to obtain a q-axis current given value;
step S4: obtaining a q-axis current actual value, and obtaining a difference value of the q-axis current by making a difference between a q-axis current set value and the q-axis current actual value;
step S5: multiplying the ratio of the expected acceleration to the actual acceleration by the difference of the q-axis current to obtain a difference amplitude limit value of the q-axis current;
the specific calculation method for limiting the amplitude of the difference value of the q-axis current according to the actual acceleration and the expected acceleration comprises the following steps:
wherein, Δ i q Is the difference amplitude limit value of the q-axis current, Δ i q Is the difference of the q-axis current, a r For actual acceleration, a c Is the desired acceleration.
When the actual acceleration a r Greater than the desired acceleration a c When a is c /a r < 1, the difference of the q-axis currents is limited, resulting in Δ i q * <Δi q (ii) a When the actual acceleration a r Less than the periodThe expected acceleration a c When a is c /a r > 1, gives Δ i q *>Δi q 。
Step S6: and the difference amplitude limit value of the q-axis current is subjected to proportional-integral operation to obtain the voltage of the q-axis.
As shown in fig. 2, which shows a system diagram of a q-axis current control method in conventional vector control, a target rotation speed n is obtained first r And actual speed n, target speed n r Obtaining a q-axis current given value i by PI proportional integral operation of a difference value delta n between the current given value and the actual rotating speed n q_ref Q-axis current setpoint i q_ref And the actual value of q-axis current i q Obtaining the difference value delta i of the q-axis current by difference q ；Δi q Finally obtaining the voltage u of the q axis through PI proportional integral operation q 。
As shown in FIG. 3, a system diagram of a q-axis current control method in improved vector control according to the present invention is shown, first, a target rotation speed n is obtained r And an actual speed n, a target speed n r Obtaining a q-axis current given value i by PI proportional integral operation of a difference value delta n between the current given value and the actual rotating speed n q_ref Q-axis current setpoint i q_ref And the actual value of q-axis current i q Obtaining the difference value delta i of the q-axis current by difference q ，Δi q Multiplied by the desired acceleration a c And the actual acceleration a r The difference amplitude limit value delta i of the q-axis current is obtained by the ratio q * ，Δi q * Finally obtaining the voltage u of the q axis through PI proportional integral operation q . Wherein the actual acceleration a r Plus is derived from the actual speed n.
Fig. 3 makes an innovation on the basis of fig. 2, the example q-axis current being more controllable.
Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope defined by the appended claims.
Claims (4)
1. A method for controlling acceleration of an electric vehicle is characterized by comprising the following steps:
step 1: acquiring the highest speed limit of the electric vehicle, and setting an initial expected acceleration according to the highest speed limit of the electric vehicle;
step 2: acquiring an actual rotating speed, calculating an actual acceleration, and adjusting an initial expected acceleration of which the expected acceleration is 1-2 times when the actual rotating speed is greater than or equal to a threshold;
and step 3: acquiring a target rotating speed from a rotating handle of the electric vehicle, calculating a difference value between the target rotating speed and an actual rotating speed, and performing proportional-integral operation on the difference value to obtain a q-axis current given value;
and 4, step 4: obtaining a q-axis current actual value, and obtaining a difference value of the q-axis current by making a difference between a q-axis current set value and the q-axis current actual value;
and 5: multiplying the ratio of the expected acceleration to the actual acceleration by the difference of the q-axis current to obtain a difference amplitude limit value of the q-axis current;
step 6: and the difference amplitude limit value of the q-axis current is subjected to proportional-integral operation to obtain the voltage of the q axis, and the PWM duty ratio in the motor vector control is controlled according to the voltage of the q axis, so that the acceleration process of the electric vehicle is completed.
2. The method for controlling the acceleration of the electric vehicle as claimed in claim 1, wherein the specific setting method for setting the initial desired acceleration in step 1 comprises:
When the highest speed limit of the electric vehicle is 25km/h, the set range of the initial expected acceleration is 10-30 r/s 2 ；
When the highest speed limit of the electric vehicle is 50km/h, the set range of the initial expected acceleration is 20-50 r/s 2 ；
When the highest speed limit of the electric vehicle is more than 50km/h, the set range of the initial expected acceleration is 25-80 r/s 2 。
3. The method for controlling the acceleration of the electric vehicle as claimed in claim 1, wherein the specific method for adjusting the desired acceleration according to the actual speed in step 2 is as follows:
when the highest speed limit of the electric vehicle is 25km/h and the actual speed is less than 5km/h, the expected acceleration is equal to the initial expected acceleration;
when the highest speed limit of the electric vehicle is 25km/h and the actual speed is not less than 5km/h, adjusting the expected acceleration to be 1-2 times of the initial expected acceleration;
when the highest speed limit of the electric vehicle is not less than 50km/h and the actual speed is less than 10km/h, the expected acceleration is equal to the initial expected acceleration;
and when the highest speed limit of the electric vehicle is not less than 50km/h and the actual speed is not less than 10km/h, adjusting the expected acceleration to be 1-2 times of the initial expected acceleration.
4. The method for controlling the acceleration of the electric vehicle as claimed in claim 1, wherein the specific calculation method for obtaining the difference limiting value of the q-axis current in the step 5 is as follows:
Wherein,
limiting the magnitude of the difference, Δ i, of the q-axis current q Is the difference of the q-axis current, a r For actual acceleration, a c Is the desired acceleration.
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| CN202011414606.1A CN112448636B (en) | 2020-12-04 | 2020-12-04 | Method for controlling acceleration of electric vehicle |
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| JPH04112690A (en) * | 1990-09-03 | 1992-04-14 | Fanuc Ltd | Control method for servo motor |
| JP3747255B2 (en) * | 1999-04-23 | 2006-02-22 | 株式会社日立製作所 | Electric vehicle control device |
| JP4299793B2 (en) * | 2005-01-20 | 2009-07-22 | ファナック株式会社 | Control device |
| CN101535913B (en) * | 2006-10-31 | 2011-03-02 | 比亚迪股份有限公司 | Control method of electromotor |
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