CN113031673B - Temperature control method for pure electric vehicle driving system - Google Patents

Abstract

The invention provides a temperature control method for a pure electric vehicle driving system, which comprises the following steps: the method comprises the following steps of carrying out first working condition test, second working condition test, numerical value recording, logic setting, logic application and logic verification; the invention obtains the motor temperature threshold value and the maximum torque value of the motor through multiple working condition tests, obtains the output torque value of the motor linearly reduced under the optimization of the motor temperature through calculation, limits the specified temperature for starting to reduce the output torque value of the motor and the value for reducing the torque value, constructs software control logic, and records the software control logic into the controller, and verifies the logic reasonableness and reduces the failure rate of the whole vehicle through the test circulation of vehicle speed rapid acceleration and rapid deceleration.

Description

A kind of pure electric vehicle drive system temperature control method

technical field

The invention relates to the technical field of vehicle temperature control, in particular to a temperature control method for a driving system of a pure electric vehicle.

Background technique

With the popularization of new energy vehicles, the environment in which pure electric vehicles are used also changes. The improvement of the battery's ability to control the external temperature can make the external environment that pure electric vehicles adapt to become wider and wider, and the more pressure it can withstand. getting closer and closer to traditional vehicles;

The basic part of pure electric vehicles is the three-electric system, including motor, motor controller, battery, battery management system, vehicle controller, on-board charger and high and low voltage DC converter. When the vehicle is running, the drive motor outputs power to drive the vehicle. , the temperature of the drive system will increase accordingly. When it rises to a certain threshold, the motor will trigger a secondary fault, and the instrument will light up the turtle light and the motor over-temperature fault light, resulting in a decrease in the power of the vehicle, giving customers a better perception. Therefore, the present invention proposes a temperature control method for a pure electric vehicle drive system to solve the problems existing in the prior art.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention proposes a temperature control method for a pure electric vehicle drive system. The pure electric vehicle drive system temperature control method obtains the motor temperature threshold and the maximum torque value of the motor through multiple working condition tests, and obtains the motor temperature optimization through calculation. The output torque value of the lower motor linearly decreases, so as to limit the specified temperature to start reducing the output torque value of the motor, as well as the value of the lower torque value, build the software control logic, and program it into the controller, and after the rapid acceleration and rapid acceleration of the vehicle speed. The deceleration test cycle verifies the rationality of the logic and reduces the failure rate of the whole vehicle. It has been verified that the present invention can stably control the temperature of the motor and reduce the failure rate.

In order to achieve the purpose of the present invention, the present invention is achieved through the following technical solutions: a temperature control method for a pure electric vehicle drive system, comprising the following steps:

Step 1: The first working condition test

Test under working condition 1: select a road with a ramp, climb the vehicle with full throttle, climb the slope for 1km after stabilizing the vehicle speed, observe the motor temperature, when the motor temperature is higher than the threshold, reach the temperature at the fault point, and record the motor temperature threshold;

Step 2: The second working condition test

Test under working condition 2: drive the vehicle on a flat road, frequently perform rapid acceleration reduction of 0-50km/h, 50-0km/h, and drive for 50 cycles. When the motor temperature is higher than the threshold, trigger the motor to overheat In case of secondary temperature fault, the meter lights up the motor over-temperature fault light and the power-limiting turtle light, and records the motor temperature threshold;

Step 3: Record the value

Compare the motor temperature thresholds recorded in working condition 1 and working condition 2, and take the average to obtain the motor temperature threshold a. At the same time, record the peak torque of the motor in working conditions 1 and 2, and record the rated torque of the motor at the same time;

Step 4: Set the logic

Set the value for optimizing the motor temperature as b, then a-b is the temperature node when the motor torque is optimized, and calculate the difference c between the peak torque of the motor and the rated torque, so that when the motor temperature reaches a-b, the calculation is 1/b. The output torque value of the motor linearly decreases under temperature;

Step 5: Logic Application

After the above records, it is obtained that the motor temperature threshold is 140°C, the motor peak torque is 110Nm, and the motor rated torque is 40Nm. The integer b is taken as 10, that is, 10°C in advance is taken as an equal fraction, and 130°C is calculated as the temperature when the motor torque is optimized. , that is, the output torque value of the motor is reduced from 130°C, and the reduced torque value is calculated to be 7Nm/°C, so as to construct the software control logic;

Step 6: Logic Verification

Program the software control logic obtained in step 5 into the motor controller. The test conditions are 0 to 50km/h rapid acceleration, rapid deceleration to 5km/h, rapid acceleration to 50km/h, and 50 cycles of driving. , collect the power CAN data of the car, and check that the motor temperature is 134°C after fifty cycles, which has not reached the temperature threshold.

A further improvement is that: in the first step, a ramp with an inclination angle of 12° is selected for the vehicle to climb with full throttle.

A further improvement is that: in the second step, the meter lights up the motor over-temperature fault light and the power-limiting turtle light. After this phenomenon occurs, it means that the motor temperature is out of control, the temperature balance point cannot be reached, and the whole vehicle has a fault mode.

A further improvement is: in the step 3, the peak torque of the motor is the maximum torque value of the motor in working conditions 1 and 2.

A further improvement is that: in the fourth step, the calculation process is: take b as the denominator of the equal ratio, take c as the numerator, and use c/b to obtain the linearly decreasing output torque value of the motor at 1/b temperature.

A further improvement is: in the fifth step, the temperature calculation formula for optimizing the motor torque is: 140°C-10°C=130°C, and in the fifth step, the calculation formula for the reduced torque value is: (110Nm-40Nm)/10°C =7Nm/°C.

A further improvement is that: in the step 5, the reduced torque value is calculated to be 7Nm/°C, and the torque value is not limited by the speed condition of the motor.

A further improvement is: in the sixth step, the motor temperature reaches the equilibrium point at 134°C, and the motor overtemperature fault is not triggered in the whole process.

The beneficial effects of the present invention are as follows: the present invention obtains the motor temperature threshold and the maximum torque value of the motor through multiple working condition tests, and obtains the output torque value of the motor linearly decreased under the motor temperature optimization through calculation, thereby limiting the start of reducing the motor output torque. The specified temperature of the value, and the value of reducing the torque value, build the software control logic, and burn it into the controller, and go through the test cycle of rapid acceleration and rapid deceleration to verify the rationality of the logic and reduce the failure rate of the whole vehicle. Experience It proves that the present invention can stably control the temperature of the motor and reduce the failure rate.

Description of drawings

Fig. 1 is the flow chart of the present invention;

Fig. 2 is the test chart that the motor temperature of the present invention cannot be controlled;

FIG. 3 is a test chart of the motor temperature controlled data of the present invention.

Detailed ways

In order to deepen the understanding of the present invention, the present invention will be described in further detail below with reference to the embodiments. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

1, 2, and 3, this embodiment proposes a temperature control method for a pure electric vehicle drive system, including the following steps:

Step 1: The first working condition test

Test under working condition 1: select a ramp road with an inclination angle of 12°, climb the vehicle with full throttle, climb the slope for 1km after stabilizing the vehicle speed, observe the motor temperature, when the motor temperature is higher than the threshold, reach the fault point temperature, record Motor temperature threshold;

Step 2: The second working condition test

Test under working condition 2: drive the vehicle on a flat road, frequently perform rapid acceleration reduction of 0-50km/h, 50-0km/h, and drive for 50 cycles. When the motor temperature is higher than the threshold, trigger the motor to overheat In case of secondary temperature fault, the meter lights up the motor over-temperature fault light and the power-limiting turtle light. When this phenomenon occurs, it means that the motor temperature is out of control and cannot reach the temperature balance point. The vehicle has a fault mode, and the motor temperature threshold is recorded;

Step 3: Record the value

Compare the motor temperature thresholds recorded in working conditions 1 and 2, and take the average to obtain the motor temperature threshold a. At the same time, record the peak torque of the motor in working conditions 1 and 2, and take the peak torque from working conditions 1 and working conditions. The maximum torque value of the motor in 2, and at the same time record the rated torque of the motor;

Step 4: Set the logic

Set the value for optimizing the motor temperature as b, then a-b is the temperature node when the motor torque is optimized, and calculate the difference c between the peak torque of the motor and the rated torque, so that when the motor temperature reaches a-b, use b as the equal denominator, Taking c as the numerator and using c/b, the output torque value of the motor linearly decreases at one part of the temperature per b;

Step 5: Logic Application

After the above records, it is obtained that the motor temperature threshold is 140°C, the motor peak torque is 110Nm, and the motor rated torque is 40Nm. The integer b is taken as 10, that is, 10°C in advance is taken as an equal fraction, and 130°C is calculated as the temperature when the motor torque is optimized. , the calculation formula is: 140°C-10°C=130°C, that is, the motor output torque value is reduced from 130°C, and the reduced torque value is calculated to be 7Nm/°C. The calculation formula is: (110Nm-40Nm)/10°C=7Nm /℃, the torque value is not limited by the motor speed condition, so as to construct the software control logic;

Step 6: Logic Verification

Program the software control logic obtained in step 5 into the motor controller. The test conditions are 0 to 50km/h rapid acceleration, rapid deceleration to 5km/h, rapid acceleration to 50km/h, and 50 cycles of driving. , collect the power CAN data of the car, check that the motor temperature is 134 ℃ after 50 cycles, reaching the equilibrium point, but not reaching the temperature threshold, the whole process does not trigger the motor over-temperature fault.

Verification example: Fig. 2 is a test of the uncontrolled motor temperature, and Fig. 3 is a test of the motor temperature controlled data after applying the present invention.

The pure electric vehicle drive system temperature control method obtains the motor temperature threshold and the maximum torque value of the motor through multiple working condition tests, and obtains the output torque value of the motor linearly decreasing under the motor temperature optimization through calculation, so as to limit the start of reducing the motor output torque. The specified temperature of the value, and the value of reducing the torque value, build the software control logic, and burn it into the controller, and go through the test cycle of rapid acceleration and rapid deceleration to verify the rationality of the logic and reduce the failure rate of the whole vehicle. Experience It proves that the present invention can stably control the temperature of the motor and reduce the failure rate.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. a pure electric vehicle drive system temperature control method, is characterized in that, comprises the following steps: Step 1: The first working condition test Test under working condition 1: select a road with a ramp, climb the vehicle with full throttle, climb the slope for 1km after stabilizing the vehicle speed, observe the motor temperature, when the motor temperature is higher than the threshold, reach the temperature at the fault point, and record the motor temperature threshold; Step 2: The second working condition test Test under working condition 2: drive the vehicle on a flat road, frequently perform rapid acceleration reduction of 0-50km/h, 50-0km/h, and drive for 50 cycles. When the motor temperature is higher than the threshold, trigger the motor to overheat In case of secondary temperature fault, the meter lights up the motor over-temperature fault light and the power-limiting turtle light, and records the motor temperature threshold; Step 3: Record the value Compare the motor temperature thresholds recorded in working conditions 1 and 2, and take the average to obtain the motor temperature threshold a. At the same time, record the peak torque of the motor in working conditions 1 and 2. The peak torque of the motor takes working conditions 1 and 2. The maximum torque value of the motor in working condition 2, and the rated torque of the motor is recorded at the same time; Step 4: Set the logic Set the value for optimizing the motor temperature as b, then a-b is the temperature node when the motor torque is optimized, and calculate the difference c between the peak torque of the motor and the rated torque, so that when the motor temperature reaches a-b, the calculation is 1/b. The output torque value of the motor that decreases linearly under temperature, the calculation process is: take b as the denominator of the equal ratio, take c as the numerator, and use c/b to obtain the output torque value of the motor that decreases linearly at one part of the temperature per b; Step 5: Logic Application After the above records, it is obtained that the motor temperature threshold is 140°C, the motor peak torque is 110Nm, and the motor rated torque is 40Nm. The integer b is taken as 10, that is, 10°C in advance is taken as an equal fraction, and 130°C is calculated as the temperature when the motor torque is optimized. , that is, the output torque value of the motor is reduced from 130°C, and the reduced torque value is calculated to be 7Nm/°C, so as to construct the software control logic; Step 6: Logic Verification Program the software control logic obtained in step 5 into the motor controller. The test conditions are 0 to 50km/h rapid acceleration, rapid deceleration to 5km/h, rapid acceleration to 50km/h, and 50 cycles of driving. , collect the power CAN data of the car, and check that the motor temperature is 134°C after fifty cycles, which has not reached the temperature threshold. 2 . The temperature control method for a pure electric vehicle drive system according to claim 1 , wherein in the first step, a ramp with an inclination angle of 12° is selected for the vehicle to climb with full throttle. 3 . 3 . The method for controlling temperature of a pure electric vehicle drive system according to claim 1 , wherein in the second step, the meter lights the motor over-temperature fault light and the power-limiting turtle light. The temperature of the motor is not controlled, the temperature equilibrium point cannot be reached, and the whole vehicle has a failure mode. 4 . The temperature control method for a pure electric vehicle drive system according to claim 1 , wherein in the step 5, the temperature calculation formula when optimizing the motor torque is: 140°C-10°C=130°C, and In step 5, the calculation formula of the reduced torque value is: (110Nm-40Nm)/10℃=7Nm/℃. 5 . The temperature control method for a pure electric vehicle drive system according to claim 1 , wherein in the step 5, the reduced torque value is calculated to be 7Nm/°C, and the torque value is not limited by the motor speed condition. 6 . . 6 . The method for controlling the temperature of a pure electric vehicle drive system according to claim 1 , wherein in the sixth step, the motor temperature reaches an equilibrium point at 134° C., and the motor over-temperature fault is not triggered in the whole process. 7 .

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