Motor current control method, device, equipment, storage medium and vehicle

Abstract

The present invention provides a motor current control method, device, equipment, storage medium and vehicle, and relates to the field of vehicle technology. The method of the present invention includes: when the requested current of the motor is greater than a first preset current threshold, a frequency reduction control strategy is executed; when the cumulative time that the requested current is greater than the first preset current threshold exceeds the preset time, a derating control strategy is executed. The present invention improves the drivability and comfort of the vehicle by first executing a frequency reduction control strategy when the requested current of the motor is greater than the first preset current threshold, avoiding serious loss of power and meeting the peak torque demand; then, when the cumulative time that the requested current is greater than the first preset current threshold exceeds the preset time, a derating control strategy is executed. By reducing the rated power of the motor, the maximum output of the motor can be limited to a certain extent, avoiding overload operation of the motor under high temperature conditions, improving the reliability and life of the motor, and thus improving the safety of the vehicle.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a motor current control method, device, equipment, storage medium and vehicle. Background Art

[0002] The hybrid system has both an engine and an electric motor, allowing the vehicle to select the engine and / or electric motor as the power source under different driving conditions, thereby optimizing fuel economy. Especially in low-speed and city driving, the pure electric mode powered only by the electric motor can reduce fuel consumption, and the vehicle has zero emissions in pure electric mode, thus meeting the requirements of energy conservation and emission reduction.

[0003] In pure electric / series mode, when the hybrid system is in full throttle (i.e., the accelerator pedal is pressed to the maximum position) driving condition, the drive motor outputs at peak torque, causing the chip phase current of the drive motor to increase instantaneously to support the vehicle's full load operation needs. However, when the chip phase current is relatively large, it will cause switching tubes such as IGBT (Insulated Gate Bipolar Transistor) to have over-temperature risks, leading to key equipment failure and power electronic system collapse, thereby affecting the vehicle's drivability, comfort and safety. Summary of the invention

[0004] The problem solved by the present invention is how to avoid the risk of overheating of the switch tube so as to improve the drivability, comfort and safety of the vehicle.

[0005] In order to solve the above problems, the present invention provides a motor current control method, device, equipment, storage medium and vehicle.

[0006] In a first aspect, the present invention provides a motor current control method, comprising:

[0007] When the requested current of the motor is greater than a first preset current threshold, executing a frequency reduction control strategy;

[0008] When the accumulated time duration during which the requested current is greater than the first preset current threshold exceeds a preset time duration, a derating control strategy is executed.

[0009] Optionally, the executing the frequency reduction control strategy includes:

[0010] Execute random frequency reduction strategy or reduce frequency according to preset fixed frequency.

[0011] Optionally, executing a random frequency reduction strategy or performing frequency reduction according to a preset fixed frequency includes:

[0012] When the requested current is greater than the first preset current threshold, frequency reduction is performed according to the preset fixed frequency;

[0013] Determine whether NVH howling occurs. If the NVH howling occurs, execute the random frequency reduction strategy. If the NVH howling does not occur, still reduce the frequency according to the preset fixed frequency.

[0014] Optionally, executing the random frequency reduction strategy includes:

[0015] Setting a random frequency reduction range, and generating a random number within the random frequency reduction range;

[0016] The power supply frequency of the motor is adjusted according to the random number.

[0017] Optionally, executing the frequency reduction control strategy further includes:

[0018] When the requested current is greater than the first preset current threshold, starting timing to determine the accumulated time;

[0019] After starting the timing, if the requested current is greater than the first preset current threshold, increasing the accumulated time;

[0020] If the requested current is less than a second preset current threshold, reducing the accumulated time, wherein the second preset current threshold is less than the first preset current threshold;

[0021] If the requested current is in the hysteresis interval, the accumulated time is adjusted according to the change direction of the requested current, wherein the lower limit value of the hysteresis interval is the second preset current threshold value and the upper limit value of the hysteresis interval is the first preset current threshold value.

[0022] Optionally, adjusting the accumulated duration according to the change direction of the requested current includes:

[0023] When the requested current decreases from being greater than the first preset current threshold to being within the hysteresis interval, increasing the accumulated time;

[0024] When the requested current increases from being less than the second preset current threshold to being within the hysteresis interval, the accumulated time length is reduced.

[0025] Optionally, the executing the derating control strategy includes:

[0026] Set the derating ratio;

[0027] The supply voltage and / or current and / or frequency limit of the motor is adjusted according to the derating ratio.

[0028] In a second aspect, the present invention provides a motor current control device, comprising:

[0029] A frequency reduction module, configured to execute a frequency reduction control strategy when the requested current of the motor is greater than a first preset current threshold;

[0030] The derating module is used to execute a derating control strategy when the cumulative time duration during which the requested current is greater than the first preset current threshold exceeds a preset time duration.

[0031] In a third aspect, the present invention provides an electronic device, including a memory and a processor;

[0032] The memory is used to store computer programs;

[0033] The processor is used to implement the above motor current control method when executing the computer program.

[0034] In a fourth aspect, the present invention provides a storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the above motor current control method is implemented.

[0035] In a fifth aspect, the present invention provides a vehicle, comprising the above motor current control device and / or the above electronic device.

[0036] The present invention first executes a frequency reduction control strategy when the requested current of the motor is greater than a first preset current threshold value, thereby only reducing the power supply frequency of the motor without changing the motor current, thereby avoiding serious loss of power and meeting the peak torque demand, thereby improving the drivability and comfort of the vehicle; then, when the cumulative time when the requested current is greater than the first preset current threshold value exceeds the preset time, the derating control strategy is executed. By reducing the rated power of the motor, the maximum output of the motor can be limited to a certain extent, avoiding overload operation of the motor under high temperature conditions, improving the reliability and life of the motor, and thus improving the safety of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the flow of a motor current control method according to an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of the architecture of a dual-motor hybrid system according to an embodiment of the present invention;

[0039] Figure 3 is a system block diagram of a motor current control device according to an embodiment of the present invention;

[0040] Figure 4 is a system block diagram of an electronic device according to an embodiment of the present invention;

[0041] Figure 5 A system block diagram of a storage medium according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] Combination Figure 2 As shown, the present invention can be applied to a dual-motor hybrid system. In the dual-motor hybrid system, the motor has three working modes: pure electric mode, series mode and parallel mode. In the parallel mode, the P2 motor drives the wheels through the transmission ratio system (RatioSystem), the clutch (C0) is not engaged, and the engine (ENG) charges the battery (Battery) through the P1 motor. In the parallel mode, the clutch (C0) is engaged, and the engine directly drives the wheels. When the driver steps on the accelerator, the control unit of the hybrid system (such as PCM, Powertrain Control Module, powertrain control module) will intelligently adjust the working mode of the engine and the motor according to the current driving conditions and system status. For example, when driving at high speed, accelerating suddenly or other situations requiring greater power, the engine provides the main power output. At this time, the motor needs to assist in providing additional power, resulting in an instantaneous increase in the chip phase current of the motor, and there is a risk of overheating.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0044] like Figure 1 As shown, an embodiment of the present invention provides a motor current control method, comprising:

[0045] When the requested current of the motor is greater than the first preset current threshold, the frequency reduction control strategy is executed.

[0046] Specifically, under full throttle driving conditions, the PCM provides maximum power and torque to meet the driver's needs. At this time, the chip phase current of the P2 motor is relatively large (for example, reaching 370Arms), which is usually reflected in the increase of the requested current of the motor. For example, the requested current is greater than the first preset current threshold (usually 90% of the maximum current), resulting in the risk of over-temperature of switching tubes such as IGBT. If the rating is directly reduced to 50%, the power loss is relatively serious. Therefore, a frequency reduction control strategy is first adopted. Under the frequency reduction control strategy, the operation of the motor will be affected, which is mainly manifested in the reduction of operating speed and output power. However, since the frequency reduction amplitude is usually small, it can still meet the peak torque demand.

[0047] Among them, PCM dynamically adjusts the drive motor by real-time monitoring of various sensor signals (such as air flow sensor, oil pressure sensor, oxygen sensor, etc.) to adapt to different driving conditions and power requirements. PCM achieves different driving modes and requirements by adjusting the working parameters of the drive motor, one of which is peak torque, which is the maximum torque value that the drive motor can provide under specific working conditions. This value is usually reached when the engine crankshaft speed reaches a certain level, depending on the design and manufacture of the drive motor.

[0048] Among them, the chip phase current refers to the current passing through the motor phase (usually three phases). In an AC motor, the current circulates between three different phases, and the magnitude and direction of the phase current depend on the working state, load, and control strategy of the motor. In general, an increase in phase current is usually associated with an increase in peak torque. When the motor is running, by increasing the phase current, the magnetic field strength generated by the motor can be increased, thereby achieving greater torque at the effective working point.

[0049] Among them, the functions of PCM include:

[0050] (1) Transmission Control: The PCM controls the shifting operation of the automatic transmission and adjusts the transmission operation according to driving conditions and driver needs.

[0051] (2) Motor control: The motor current can be controlled according to the motor torque request to ensure the motor torque output.

[0052] (3) Fault diagnosis: The PCM has a fault diagnosis function that can monitor the operating status of the vehicle system and generate a fault code when a problem is found to help technicians identify and repair the problem.

[0053] Among them, IGBT is a transistor commonly used in power electronic devices. In the power electronic system of a vehicle, IGBT is usually used to control parts such as motors and inverters. When the current increases instantaneously, the IGBT may be subjected to a certain thermal load, resulting in an over-temperature risk. IGBT generates power loss when it is in the on state, and its magnitude is proportional to the current. Therefore, an increase in current will cause an instantaneous increase in power loss, causing the IGBT to generate more heat. Due to the power loss, the temperature of the IGBT may increase instantaneously. If this temperature increase exceeds the rated operating temperature range of the IGBT, it may cause an over-temperature problem. If the IGBT overheats and causes a failure, it may cause a series of serious consequences, some of which may include:

[0054] (1) Equipment failure: IGBT may fail or be damaged under over-temperature conditions, which may cause the failure of key components such as motor drive, inverter, power supply, etc., and thus cause the vehicle to fail to work properly.

[0055] (2) System crash: IGBT failure may cause the entire power electronics system to crash, which may cause the vehicle to lose power, braking and other important functions, increasing the risk of driving safety.

[0056] (3) Fire risk: Overheating of the IGBT may cause surrounding electronic components and wire insulation materials to become unstable, increasing the risk of fire.

[0057] (4) High repair costs: IGBTs are expensive components in vehicle power electronics systems. If they are damaged due to over-temperature failures, the cost of replacement and repair may be high, putting pressure on vehicle maintenance and repair budgets.

[0058] (5) Safety risks: When a vehicle is driving, IGBT overheating may cause power loss or brake system failure, thereby increasing the risk of traffic accidents and posing a threat to the safety of the driver and other road users.

[0059] When the accumulated time duration during which the requested current is greater than the first preset current threshold exceeds a preset time duration, a derating control strategy is executed.

[0060] Specifically, when the cumulative time that the requested current is greater than the first preset current threshold exceeds the preset time (for example, 10s), there is a risk of overheating in the switching tube and a derating control strategy needs to be adopted. By reducing the rated power of the motor, the maximum output of the motor can be limited to a certain extent, avoiding overload operation of the motor under high temperature conditions and improving the reliability and life of the motor.

[0061] This embodiment first executes a frequency reduction control strategy when the requested current of the motor is greater than a first preset current threshold value, thereby only reducing the power supply frequency of the motor without changing the motor current, thereby avoiding serious loss of power and meeting the peak torque demand, thereby improving the drivability and comfort of the vehicle; then, when the cumulative duration of the requested current being greater than the first preset current threshold value exceeds the preset duration, a derating control strategy is executed. By reducing the rated power of the motor, the maximum output of the motor can be limited to a certain extent, avoiding overload operation of the motor under high temperature conditions, improving the reliability and life of the motor, and thus improving the safety of the vehicle.

[0062] Optionally, the executing the frequency reduction control strategy includes:

[0063] Execute random frequency reduction strategy or reduce frequency according to preset fixed frequency.

[0064] Specifically, in the frequency reduction control strategy, a random frequency reduction strategy can be adopted, or the frequency can be reduced according to a preset fixed frequency (that is, the frequency is reduced according to a preset fixed frequency, and the preset fixed frequency is less than the current power supply frequency of the motor). Considering the NVH (Noise, Vibration, Harshness) noise problem, a random frequency reduction strategy is usually adopted for frequency reduction.

[0065] Optionally, executing a random frequency reduction strategy or performing frequency reduction according to a preset fixed frequency includes:

[0066] When the requested current is greater than the first preset current threshold, the frequency is reduced according to the preset fixed frequency.

[0067] Specifically, when the requested current of the motor is greater than a first preset current threshold, the frequency is first reduced according to a preset fixed frequency.

[0068] Determine whether NVH howling occurs. If the NVH howling occurs, execute the random frequency reduction strategy. If the NVH howling does not occur, still reduce the frequency according to the preset fixed frequency.

[0069] Specifically, it is then determined whether NVH howling occurs. If NVH howling occurs, it means that frequency reduction according to the preset fixed frequency has caused NVH noise problems. At this time, a random frequency reduction strategy is executed. If NVH howling does not occur, frequency reduction is still performed according to the preset fixed frequency.

[0070] Optionally, executing the random frequency reduction strategy includes:

[0071] A random frequency reduction range is set, and a random number is generated within the random frequency reduction range.

[0072] Specifically, the random frequency reduction range is first set to determine the upper and lower limits of the power supply frequency, that is, the frequency range in which the motor can be randomly adjusted during operation; at each frequency reduction time interval, a random number is generated (by using a random number generator or other randomization algorithm), and the random number is within the random frequency reduction range.

[0073] The power supply frequency of the motor is adjusted according to the random number.

[0074] Specifically, the generated random number is mapped to the power supply frequency range of the motor, and then the frequency of the motor is adjusted to the corresponding frequency (the corresponding frequency is less than the current frequency), so that the motor changes randomly within the specified frequency range to achieve the purpose of frequency reduction.

[0075] Optionally, executing the frequency reduction control strategy further includes:

[0076] When the requested current is greater than the first preset current threshold, timing is started to determine the accumulated time.

[0077] Specifically, when the requested current is greater than a first preset current threshold (usually 90% of the maximum current), timing starts to determine the current accumulated duration.

[0078] After the timing starts, if the requested current is greater than the first preset current threshold, the accumulated time is increased.

[0079] Specifically, if the requested current is greater than a first preset current threshold (usually 90% of the maximum current), the accumulated time is increased. For example, the timing is started from 0s, and the accumulated time is increased as long as the requested current is greater than the first preset current threshold.

[0080] If the requested current is less than a second preset current threshold, the accumulated time is reduced, wherein the second preset current threshold is less than the first preset current threshold.

[0081] Specifically, if the requested current is less than the second preset current threshold (usually 80% of the maximum current), the accumulated time is reduced. For example, when the accumulated time is 8s, as long as the requested current is less than the second preset current threshold, the accumulated time is reduced to 7s or 6s.

[0082] If the requested current is in the hysteresis interval, the accumulated time is adjusted according to the change direction of the requested current, wherein the lower limit value of the hysteresis interval is the second preset current threshold value and the upper limit value of the hysteresis interval is the first preset current threshold value.

[0083] Specifically, if the requested current is in the hysteresis range, that is, 80% to 90% of the maximum current, the accumulated time is adjusted according to the change direction of the requested current, and the specific content is shown below.

[0084] Optionally, adjusting the accumulated duration according to the change direction of the requested current includes:

[0085] When the requested current decreases from being greater than the first preset current threshold to being within the hysteresis interval, the accumulated time is increased.

[0086] Specifically, if the requested current is reduced from 95% of the maximum current to 85% of the maximum current, the accumulated time is increased.

[0087] When the requested current increases from being less than the second preset current threshold to being within the hysteresis interval, the accumulated time length is reduced.

[0088] Specifically, if the requested current increases from 75% of the maximum current to 85% of the maximum current, the accumulated time is reduced; by setting the hysteresis interval, problems such as misidentification caused by the change in current direction within the hysteresis interval can be avoided. For example, the requested current decreases from 95% of the maximum current to 85% of the maximum current, and then continues to decrease. As long as it does not decrease to less than the second preset current threshold (usually 80% of the maximum current), even if the requested current increases from 85% of the maximum current to 86% (i.e., the current changes direction, but the requested current is within the hysteresis interval), the accumulated time continues to increase.

[0089] Optionally, the executing the derating control strategy includes:

[0090] Set the derating ratio.

[0091] Specifically, the derating ratio is first set, for example, the rated power of the motor is adjusted to 50% of the original power.

[0092] The supply voltage and / or current and / or frequency limit of the motor is adjusted according to the derating ratio.

[0093] Specifically, after setting the derating ratio, it is necessary to adjust the motor's supply voltage, current (for example, the current is adjusted to 50% of the original) and / or frequency limit accordingly to ensure that the motor operates at the new rated power, such as adjusting the settings of the motor driver to ensure that the motor operates under the new parameters.

[0094] Another embodiment of the present invention provides a motor current control device, comprising:

[0095] A frequency reduction module, configured to execute a frequency reduction control strategy when the requested current of the motor is greater than a first preset current threshold;

[0096] The derating module is used to execute a derating control strategy when the cumulative time duration during which the requested current is greater than the first preset current threshold exceeds a preset time duration.

[0097] Another embodiment of the present invention provides an electronic device, including a memory 402 and a processor 401 (which may be connected to each other via a bus 400);

[0098] The memory is used to store computer programs;

[0099] The processor is used to implement the above motor current control method when executing the computer program.

[0100] Another embodiment of the present invention provides a storage medium having a computer program stored thereon. When the computer program is executed by a processor, the above motor current control method is implemented.

[0101] Another embodiment of the present invention provides a vehicle, comprising the above motor current control device and / or the above electronic device.

[0102] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A motor current control method, characterized in that: include: When the requested current of the motor is greater than a first preset current threshold, executing a frequency reduction control strategy; When the cumulative time duration during which the requested current is greater than the first preset current threshold exceeds a preset time duration, executing a derating control strategy; Wherein, the motor current control method further includes: When the requested current is greater than the first preset current threshold, starting timing to determine the accumulated time; After starting the timing, if the requested current is greater than the first preset current threshold, increasing the accumulated time; If the requested current is less than a second preset current threshold, reducing the accumulated time, wherein the second preset current threshold is less than the first preset current threshold; If the requested current is in the hysteresis interval, the accumulated time is adjusted according to the change direction of the requested current, wherein the lower limit value of the hysteresis interval is the second preset current threshold value and the upper limit value of the hysteresis interval is the first preset current threshold value.

2. The motor current control method according to claim 1, characterized in that: The execution of the frequency reduction control strategy includes: Execute random frequency reduction strategy or reduce frequency according to preset fixed frequency.

3. The motor current control method according to claim 2, characterized in that: The executing of the random frequency reduction strategy or frequency reduction according to a preset fixed frequency includes: When the requested current is greater than the first preset current threshold, frequency reduction is performed according to the preset fixed frequency; Determine whether NVH howling occurs. If the NVH howling occurs, execute the random frequency reduction strategy. If the NVH howling does not occur, still reduce the frequency according to the preset fixed frequency.

4. The motor current control method according to claim 2 or 3, characterized in that: The implementation of the random frequency reduction strategy includes: Setting a random frequency reduction range, and generating a random number within the random frequency reduction range; The power supply frequency of the motor is adjusted according to the random number.

5. The motor current control method according to claim 1, characterized in that: The adjusting the accumulated duration according to the change direction of the requested current includes: When the requested current decreases from being greater than the first preset current threshold to being within the hysteresis interval, increasing the accumulated time; When the requested current increases from being less than the second preset current threshold to being within the hysteresis interval, the accumulated time length is reduced.

6. The motor current control method according to claim 1, characterized in that: The execution of the derating control strategy includes: Set the derating ratio; The supply voltage and / or current and / or frequency limit of the motor is adjusted according to the derating ratio.

7. A motor current control device, characterized in that: include: A frequency reduction module, configured to execute a frequency reduction control strategy when the requested current of the motor is greater than a first preset current threshold; A derating module, configured to execute a derating control strategy when the cumulative duration for which the requested current is greater than the first preset current threshold exceeds a preset duration; Wherein, the derating module is also used for: When the requested current is greater than the first preset current threshold, starting timing to determine the accumulated time; After starting the timing, if the requested current is greater than the first preset current threshold, increasing the accumulated time; If the requested current is less than a second preset current threshold, reducing the accumulated time, wherein the second preset current threshold is less than the first preset current threshold; If the requested current is in the hysteresis interval, the accumulated time is adjusted according to the change direction of the requested current, wherein the lower limit value of the hysteresis interval is the second preset current threshold value and the upper limit value of the hysteresis interval is the first preset current threshold value.

8. An electronic device, characterized in that: including memory and processor; The memory is used to store computer programs; The processor is used to implement the motor current control method as described in any one of claims 1-6 when executing the computer program.

9. A storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by the processor, the motor current control method according to any one of claims 1 to 6 is implemented.

10. A vehicle, characterized in that: It comprises the motor current control device as claimed in claim 7 and / or the electronic device as claimed in claim 8.

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