CN114976370A - Battery pulse heating control system, method, vehicle and storage medium - Google Patents

Abstract

The invention discloses a battery pulse heating control system, a battery pulse heating control method, a vehicle and a storage medium, wherein the battery pulse heating control system comprises the following steps: after the start of pulse heating of the power battery is detected, detecting whether a hardware overcurrent fault occurs through a motor controller; if the motor controller does not report the hardware overcurrent fault, increasing the current of the power battery during pulse heating, wherein the specific mode of increasing the current of the power battery during pulse heating is as follows: reducing the PWM wave switching frequency f and increasing Ud and Uq, wherein Ud is direct axis voltage under a motor rotating coordinate system, and Uq is quadrature axis voltage under the motor rotating coordinate system; if the motor controller reports the hardware overcurrent fault, reducing the pulse heating current of the power battery, wherein the specific mode of reducing the pulse heating current of the power battery is as follows: increasing the PWM wave switching frequency f, decreasing Ud and Uq. The invention improves the pulse heating efficiency of the power battery and ensures the safety and reliability of the hardware of the motor controller.

Description

Battery pulse heating control system, method, vehicle and storage medium

technical field

The invention belongs to the technical field of rapid pulse heating of power batteries, and in particular relates to a battery pulse heating control system, method, vehicle and storage medium.

Background technique

The power battery of electric vehicles will have problems such as voltage drop and discharge capacity reduction under low temperature conditions, so it is necessary to quickly heat the battery to an appropriate temperature. By controlling the motor controller to adjust the PWM wave switching frequency and PWM duty cycle, the pulse current flowing through the battery is controlled to heat the cell. This method is more efficient and less expensive than traditional methods of heating by external heat conduction.

However, the current common pulse heating control method still has the following problems: the motor inductance is not the same when the motor rotor is in different positions, and because the sampling frequency of the current by the motor controller software is usually the PWM switching frequency, which is the center point of the PWM , and the maximum current of the pulse heating appears at the turn-off point of the PWM, which makes the software unable to accurately obtain the three-phase current during the pulse heating period, which is difficult to close-loop control. Therefore, the software leaves a certain margin in the control algorithm to limit the current size and prevent the hardware Damaged, eventually resulting in insufficient use of the motor controller to heat the battery during the pulse heating process.

Therefore, it is necessary to develop a new battery pulse heating control system, method, vehicle and storage medium.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a battery pulse heating control system, method, vehicle and storage medium, so as to improve the power battery pulse heating efficiency and ensure the safety and reliability of the motor controller hardware.

In the first aspect, a battery pulse heating control method according to the present invention includes the following steps:

After detecting the start of pulse heating of the power battery, check whether the hardware overcurrent fault occurs through the motor controller:

If the motor controller does not report a hardware overcurrent fault, the current during the pulse heating of the power battery is increased, wherein the specific method of increasing the current during the pulse heating of the power battery is: reducing the PWM wave switching frequency f, increasing Ud and Uq, where Ud is the direct-axis voltage in the motor rotating coordinate system, and Uq is the quadrature-axis voltage in the motor rotating coordinate system;

If the motor controller reports a hardware overcurrent fault, the current of the pulse heating of the power battery is reduced, wherein the specific method of reducing the current of the pulse heating of the power battery is: increasing the PWM wave switching frequency f, and reducing Ud and Uq ;

That is to find the PWM wave switching frequency f, Ud, Uq corresponding to the hardware maximum current through the hardware overcurrent fault state of the motor controller.

Optionally, in response to the motor controller reporting a hardware overcurrent fault, the number of faults is recorded.

Optionally, after it is detected that the pulse heating of the power battery starts, the method further includes:

Determine whether the number of failures is less than or equal to the preset number;

If the number of faults is less than or equal to the preset number of times, the motor controller will detect whether a hardware overcurrent fault occurs, and continue to adjust the PWM wave switching frequency f, Ud and Uq to find the hardware maximum current state;

If the number of failures is greater than the preset number, the current PWM wave switching frequencies f, Ud and Uq are considered to be the PWM wave switching frequencies f, Ud and Uq corresponding to the hardware maximum current, and the current PWM wave switching frequencies f, Ud and Uq are maintained; In order to prevent the overcurrent fault from being triggered by mistake, multiple judgments are adopted.

Optionally, also include:

Set the hardware overcurrent fault of the motor controller as a recoverable fault, and clear the fault before increasing the PWM wave switching frequency f and reducing Ud and Uq, and increase the number of faults by 1 at the same time.

Optionally, while increasing and decreasing the PWM wave switching frequency f, and adjusting Ud and Uq, the PWM duty cycle is kept within a preset value to ensure that the three-phase current ratio remains unchanged and the motor output torque is zero.

In the second aspect, a battery pulse heating control system according to the present invention includes a memory and a controller, wherein a computer-readable program is stored in the memory, and the computer-readable program can execute the present invention when called by the controller. The steps of the battery pulse heating control method.

In a third aspect, a vehicle according to the present invention adopts the battery pulse heating control system according to the present invention.

In a fourth aspect, a storage medium according to the present invention stores a computer-readable program therein, and the computer-readable program can execute the steps of the battery pulse heating control method according to the present invention when the computer-readable program is called.

The present invention has the following advantages: the present invention utilizes the hardware overcurrent protection mechanism of the motor controller to adjust the current of the power module in a closed loop, thereby realizing the maximum control of the battery pulse heating current, improving the power battery pulse heating efficiency, and ensuring the motor controller. Hardware security and reliability.

Description of drawings

FIG. 1 is a flowchart of the first embodiment.

FIG. 2 is a flowchart of the second embodiment.

3 is a schematic diagram of the three-phase current waveforms Ia, Ib, Ic, the DC current waveform, the PWM wave switching frequency f, the direct-axis voltage Ud, and the quadrature-axis voltage Uq in the second embodiment.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings.

Example 1

As shown in FIG. 1, in this embodiment, a battery pulse heating control method includes the following steps:

Step A1. After detecting the start of pulse heating of the power battery, check whether a hardware overcurrent fault occurs through the motor controller.

Step A2. If the motor controller does not report a hardware overcurrent fault, increase the current during the pulse heating of the power battery, and return to step A1; wherein, the specific method of increasing the current during the pulse heating of the power battery is: reducing The PWM wave switching frequency f increases Ud and Uq, where Ud is the direct axis voltage under the motor rotating coordinate system, and Uq is the quadrature axis voltage under the motor rotating coordinate system.

Step A3. If the motor controller reports a hardware overcurrent fault, reduce the current of the pulse heating of the power battery, and return to step A1; wherein, the specific method of reducing the current of the pulse heating of the power battery is: increasing the PWM wave switch Frequency f, reduce Ud and Uq.

In this embodiment, the PWM wave switching frequencies f, Ud and Uq are continuously adjusted according to the hardware overcurrent fault state detected by the motor controller, and the PWM wave switching frequencies f, Ud and Uq corresponding to the maximum hardware current are found. For NVH consideration, the PWM wave switching frequency f is a frequency range within which a larger current and better NVH experience can be obtained.

According to the formula Q=I ² Rt, it can be known that the calorific value Q of the internal resistance Rt of the battery is proportional to the square of the current I, so increasing the charging and discharging current of the battery during pulse heating can improve the efficiency of pulse heating. The rising slope of the pulse current is limited by the motor inductance. When the motor inductance is fixed, in order to increase the current, the current value can be increased by adjusting the switching frequency f of the PWM wave and the duty cycle. Among them, the duty ratio is calculated by Ud and Uq according to the principle of vector control from the bus voltage. In this embodiment, the maximum duty cycle of PWM is kept within a certain value (such as 90%) while increasing and decreasing the PWM wave switching frequency f, adjusting Ud and Uq, so as to ensure that the three-phase current ratio remains unchanged, and the motor The output torque is zero. By precisely controlling the switching frequency of the PWM and the duty cycle of the PWM, the method ensures the high efficiency of the pulse heating of the power battery.

In this embodiment, a battery pulse heating control system includes a memory and a controller, wherein a computer-readable program is stored in the memory, and the computer-readable program can be executed as described in this embodiment when called by the controller The steps of the battery pulse heating control method.

In this embodiment, a vehicle adopts the battery pulse heating control system as described in this embodiment.

In this embodiment, a storage medium stores a computer-readable program therein, and when the computer-readable program is invoked, the steps of the battery pulse heating control method described in this embodiment can be executed.

Embodiment 2

As shown in FIG. 2, in this embodiment, a battery pulse heating control method includes the following steps:

Step B1: After detecting the start of pulse heating of the power battery, determine whether the number of failures is less than or equal to the preset number of times, if the number of failures is less than or equal to the preset number of times, go to step B2; if the number of failures is greater than the preset number of times, go to step B3.

Step B2: Detect whether a hardware overcurrent fault occurs through the motor controller, and continue to adjust the PWM wave switching frequency f, Ud and Uq to find the hardware maximum current state; specifically:

If the motor controller does not report a hardware overcurrent fault, reduce the PWM wave switching frequency f, increase Ud and Uq, and return to step B1;

If the motor controller reports a hardware overcurrent fault, the fault is cleared, and the number of faults is increased by 1, the PWM wave switching frequency f is increased, Ud and Uq are decreased, and the process returns to step B1;

Step B3: The current PWM wave switching frequencies f, Ud and Uq are considered to be the PWM wave switching frequencies f, Ud and Uq corresponding to the hardware maximum current, and the current PWM wave switching frequencies f, Ud and Uq are maintained.

In this embodiment, the method of multiple judgments is adopted, the purpose of which is to prevent the overcurrent fault from being triggered by mistake, that is, after the start of pulse heating of the power battery is detected, and the number of faults is greater than the preset number, the current PWM wave switching frequency is maintained. f, Ud and Uq; otherwise, continuously adjust the PWM wave switching frequencies f, Ud and Uq until the PWM wave switching frequencies f, Ud and Uq corresponding to the maximum hardware current are found to ensure that the motor controller works at the maximum current state.

In this embodiment, the hardware overcurrent fault of the motor controller is set as a recoverable fault, and the number of faults is increased by 1 when the fault is cleared.

After continuously adjusting the PWM wave switching frequency, Ud and Uq, and after repeatedly triggering the hardware overcurrent fault and recovering, the method can lock the maximum current value that can be output in the current state and the corresponding PWM wave switching frequencies f, Ud and Uq. At this time, the hardware current of the motor controller will be near the maximum allowable current, and the pulse heating current of the power battery will reach the maximum.

As shown in Figure 3, from top to bottom are the corresponding relationship diagrams of the three-phase current waveforms Ia, Ib, Ic, the DC current waveform Idc, the PWM wave switching frequency f, the direct-axis voltage Ud, and the quadrature-axis voltage Uq. The abscissas in 3 all represent time. It can be seen from Figure 3 that after detecting the start of pulse heating of the power battery, the PWM wave switching frequency f is firstly searched downward, and the PWM wave switching frequency f is continuously reduced. When the PWM wave switching frequency f is reduced to a certain value If the current number of faults is less than the preset number, the fault will be cleared, the number of faults will be +1, and the switching frequency f of the PWM wave will be appropriately increased, and so on until the number of faults reaches the preset number. When the number of times is set, it means that the PWM wave switching frequency f, Ud and Uq corresponding to the hardware maximum current has been found.

The rest is the same as the first embodiment.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (8)

1. A battery pulse heating control method is characterized by comprising the following steps:

after the start of pulse heating of the power battery is detected, detecting whether a hardware overcurrent fault occurs through a motor controller;

if the motor controller does not report the hardware overcurrent fault, increasing the current of the power battery during pulse heating, wherein the specific mode of increasing the current of the power battery during pulse heating is as follows: reducing the PWM wave switching frequency f and increasing Ud and Uq, wherein Ud is direct axis voltage under a motor rotating coordinate system, and Uq is quadrature axis voltage under the motor rotating coordinate system;

if the motor controller reports the hardware overcurrent fault, reducing the pulse heating current of the power battery, wherein the specific mode of reducing the pulse heating current of the power battery is as follows: increasing the PWM wave switching frequency f and reducing Ud and Uq;

namely, the PWM wave switching frequencies f, Ud and Uq corresponding to the hardware maximum current are searched through the hardware overcurrent fault state of the motor controller.

2. The battery pulse heating control method according to claim 1, characterized in that: and recording the number of times of the faults when the motor controller reports the hardware overcurrent faults.

3. The battery pulse heating control method according to claim 2, characterized in that: after detecting that the pulse heating of the power battery is started, the method further comprises the following steps:

judging whether the failure times are less than or equal to preset times;

if the fault frequency is less than or equal to the preset frequency, detecting whether a hardware overcurrent fault occurs through the motor controller, continuously adjusting the PWM wave switching frequency f, the Ud and the Uq, and searching the maximum current state of the hardware;

and if the fault frequency is greater than the preset frequency, determining that the current PWM wave switching frequencies f, Ud and Uq are the PWM wave switching frequencies f, Ud and Uq corresponding to the maximum hardware current, and keeping the current PWM wave switching frequencies f, Ud and Uq.

4. The battery pulse heating control method according to claim 3, further comprising:

setting the overcurrent fault of the hardware of the motor controller as a recoverable fault, clearing the fault before increasing the switching frequency f of the PWM wave and reducing the Ud and the Uq, and adding 1 to the number of the faults.

5. The battery pulse heating control method according to claim 4, characterized in that: the PWM duty ratio is kept within a preset value while increasing and reducing the PWM wave switching frequency f and adjusting the Ud and the Uq so as to ensure that the proportion of three-phase current is unchanged and the output torque of the motor is zero.

6. A battery pulse heating control system, characterized by: comprising a memory and a controller, said memory having stored therein a computer readable program capable of executing the steps of the method of battery pulse heating control according to any one of claims 1 to 5 when invoked by the controller.

7. A vehicle, characterized in that: a battery pulse heating control system as defined in claim 6.

8. A storage medium, characterized by: stored with a computer readable program which when invoked is able to perform the steps of the battery pulse heating control method according to any one of claims 1 to 5.

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