Motor torque degradation control method and vehicle

Abstract

The application provides a motor torque degradation control method and a vehicle, and relates to the technical field of vehicles.The motor torque degradation control method comprises the following steps: monitoring whether a torque degradation condition is triggered; when the torque degradation condition is triggered, determining a target torque according to a change value of an abnormal factor corresponding to the torque degradation condition, and adjusting the target torque according to a friction torque and a load torque, so as to avoid the target torque fluctuating between an upper limit value and a lower limit value of jitter.The application monitors the torque degradation condition, enters a torque degradation control mode when the torque degradation condition is triggered, determines the target torque according to the change value of the abnormal factor corresponding to the torque degradation condition, and adjusts the target torque according to the friction torque and the load torque, so as to avoid the torque range causing the motor rotor to jitter, avoid the target torque fluctuating near zero torque and causing the rotor to abnormally jitter, and further improve driving comfort and vehicle stability.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and more specifically, to a method for controlling motor torque degradation and a vehicle. Background Technology

[0002] Inside electric vehicles, the electric drive system often fails due to overheating, overcurrent, overspeed, and overvoltage. To avoid these failures, monitoring strategies are usually added to the software to monitor temperature, current, speed, and voltage signals. When these signal values ​​enter a specific range, the torque is reduced.

[0003] However, current torque degradation strategies can cause abnormal rotor vibration due to fluctuations near zero torque, which may lead to problems such as reduced driving comfort and decreased vehicle stability. Summary of the Invention

[0004] The problem addressed by this invention is how to avoid abnormal jitter during torque degradation.

[0005] To address the aforementioned problems, this invention provides a method for controlling motor torque degradation and a vehicle.

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

[0007] Monitor whether the torque degradation condition is triggered;

[0008] When the torque degradation condition is triggered, the target torque is determined based on the change value of the abnormal factor corresponding to the torque degradation condition, and the target torque is adjusted according to the friction torque and load torque to avoid the target torque fluctuating between the upper limit and lower limit of the jitter.

[0009] Optionally, whether the monitored torque degradation condition is triggered includes:

[0010] Monitor whether the motor's temperature, current, speed, and voltage meet the triggering conditions for the corresponding torque degradation condition.

[0011] Optionally, the triggering conditions for monitoring whether the temperature, current, speed, and voltage of the motor meet the corresponding torque degradation conditions include:

[0012] The torque degradation condition is determined to be triggered when at least one of the following conditions is met: the temperature is greater than a preset temperature, the current is greater than a preset current, the rotational speed is greater than a preset rotational speed, and the voltage is greater than a preset voltage.

[0013] Optionally, determining the target torque based on the change value of the anomaly factor corresponding to the torque degradation condition includes:

[0014] The target torque is determined based on the change value, the degradation factor, and the required torque.

[0015] Optionally, determining the target torque based on the change value, the degradation factor, and the required torque includes:

[0016] The corresponding target torque calculation formula is determined based on the aforementioned anomaly factor;

[0017] Based on the target torque calculation formula, the target torque is determined according to the change value, the degradation coefficient, and the required torque.

[0018] Optionally, adjusting the target torque based on the friction torque and the load torque includes:

[0019] The vibration determination value is determined based on the target torque, the friction torque, and the load torque;

[0020] When the vibration determination value is within the preset range, the target torque is adjusted.

[0021] Optionally, adjusting the target torque when the vibration determination value is within a preset range includes:

[0022] When the jitter determination value is between the upper limit of jitter and the lower limit of jitter, the target torque is reduced.

[0023] Optionally, adjusting the target torque when the vibration determination value is within a preset range further includes:

[0024] The reduction value of the target torque is determined based on the upper limit value of the jitter and the lower limit value of the jitter.

[0025] Optionally, adjusting the target torque based on the friction torque and the load torque further includes:

[0026] Based on the dynamic equations of the electric drive system, the load torque is determined according to the motor torque, motor speed, friction torque, and moment of inertia.

[0027] In a second aspect, the present invention provides a vehicle including a computer-readable storage medium storing a computer program and a processor, wherein the computer program is read and executed by the processor to implement the above-described motor torque degradation control method.

[0028] This invention monitors torque degradation conditions and enters a torque degradation control mode when the conditions are triggered. It determines the target torque based on the change value of the abnormal factor corresponding to the torque degradation conditions, and then adjusts the target torque based on the friction torque and load torque. This avoids the torque range that causes motor rotor vibration and prevents abnormal rotor vibration caused by fluctuations near zero torque, thereby improving driving comfort and vehicle stability. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating the motor torque degradation control method according to an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of the torque degradation strategy according to an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the system structure of electronic devices in a vehicle according to an embodiment of the present invention. Detailed Implementation

[0032] Abnormal vibrations in the electric drive system can have a series of negative effects on the vehicle. Factors affecting this can include the motor, electronic control system, and transmission system. The following are some possible impacts:

[0033] (1) Decreased driving comfort: Vibration can cause an unpleasant shuddering sensation during vehicle operation, reducing driving comfort.

[0034] (2) Reduced vehicle stability: Vibration may affect the stability of the vehicle, especially when driving at high speed or on curves, and may increase the risk of loss of control, especially in emergency situations.

[0035] (3) Damage to motor and transmission system: Long-term abnormal vibration may put additional pressure on the motor and transmission system, leading to wear and damage to parts.

[0036] (4) Decreased energy efficiency: Vibration may lead to a decrease in energy efficiency because some energy is converted into vibration instead of driving the vehicle, which may result in a waste of battery energy and reduce the range of electric vehicles.

[0037] (5) System errors and faults: Abnormal jitter may be a manifestation of internal problems in the electric drive system, such as motor controller failure, sensor problems, etc., which may lead to system errors and faults and affect the performance of the entire electric drive system.

[0038] (6) Driver fatigue: Continuous shaking may cause driver fatigue, requiring more effort to maintain control of the vehicle, which may affect the driver's attention and reaction time.

[0039] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0040] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0041] like Figure 1 As shown, an embodiment of the present invention provides a method for motor torque degradation control, including:

[0042] Monitor whether the torque degradation condition is triggered.

[0043] Specifically, under normal operating conditions, the motor controller periodically monitors torque degradation conditions.

[0044] When the torque degradation condition is triggered, the target torque is determined based on the change value of the abnormal factor corresponding to the torque degradation condition, and the target torque is adjusted according to the friction torque and load torque to avoid the target torque fluctuating between the upper limit and lower limit of the jitter.

[0045] Specifically, in torque degradation control mode, the target torque is determined based on the change value of the abnormal factor. To avoid fluctuations near zero torque, the target torque is further adjusted based on the friction torque and load torque (calculated based on the undegraded state). This avoids the torque range that causes motor rotor vibration, preventing fluctuations near zero torque (between the upper and lower limits of vibration) that could lead to abnormal rotor vibration (near zero torque, the system may become particularly sensitive, and small torque fluctuations can be enough to affect rotor stability; when the frequency of torque fluctuations approaches the system's resonant frequency, it can easily cause vibration amplification, resulting in vibration). Since the time consumed by the motor controller to calculate and control the torque is very short, the speed change of the entire vehicle is very small during this period, which can be understood as relatively steady state, meaning the load torque is a relatively constant value.

[0046] During normal operation of the electric drive system, the motor controller controls the motor's output torque based on both the vehicle controller's required torque and the actual conditions of the electric drive system itself. This torque drives the reducer, which in turn drives the transmission shaft, ultimately propelling the vehicle. The dynamic equations of the electric drive system in this process are as follows:

[0047]

[0048] T b =Bω; (2)

[0049] Where J represents the system's moment of inertia, ω represents the rotor's angular velocity, and T... e T represents motor torque (or motor torque). b T represents frictional torque. l B represents the load torque, and B represents the coefficient of friction.

[0050] Based on formula (1), it can be seen that the angular acceleration of the motor rotor is the result of the combined action of the motor torque, friction torque, and load torque, where the friction torque T is... b The proportionality coefficient is directly proportional to the actual rotational speed, which is the friction coefficient B. The vibration of the motor is mainly due to the frequent commutation of the rotor's angular acceleration, that is, the angular acceleration is sometimes positive and sometimes negative. According to formula (1), the sign of the angular acceleration depends on (T). e -T b -T l The sign of (T) is positive or negative, and the frequent changes in sign are due to (T) e -T b -T l The value of (T) fluctuates around zero; therefore, avoid (T) e -T b -T l Fluctuating the value of ) around zero is an effective way to suppress rotor fluctuations.

[0051] Among them, motor torque refers to the torque generated by the motor, enabling it to rotate or provide mechanical output; friction torque is the torque generated due to friction between mechanical components, including bearing friction, gear friction, and friction between other moving parts. Friction torque is the source of energy loss in a mechanical system and can slow down the system's movement, requiring the motor to generate more torque to overcome it; load torque is the torque from external mechanical loads that the motor must overcome, including torque caused by devices, tools, mechanical equipment, etc. connected to the motor. Load torque is the additional torque that the motor must provide to drive the load.

[0052] Optionally, whether the monitored torque degradation condition is triggered includes:

[0053] Monitor whether the motor's temperature, current, speed, and voltage meet the triggering conditions for the corresponding torque degradation condition.

[0054] Specifically, the common triggering conditions include the following four:

[0055] (1) Overheating: The temperature of the controller IGBT (Insulated-Gate Bipolar Transistor) and the motor stator winding is too high, for example, the IGBT temperature is higher than 80 to 90 degrees Celsius and the motor temperature is higher than 130 to 140 degrees Celsius.

[0056] (2) Overcurrent: The current through the controller IGBT and the motor stator winding is too large, for example, the RMS value (Root Meam Square) of the three-phase current is greater than 95% of the IGBT's allowable current limit.

[0057] (3) Overspeed: The rotor speed of the motor is too high, for example, the speed of the motor exceeds the maximum speed limit of the motor, such as 16,500 rpm.

[0058] (4) Overvoltage: The bus voltage applied to the IGBT is too high, for example, the bus voltage exceeds 5% to 15% of the motor's rated voltage.

[0059] Optionally, the triggering conditions for monitoring whether the temperature, current, speed, and voltage of the motor meet the corresponding torque degradation conditions include:

[0060] The torque degradation condition is determined to be triggered when at least one of the following conditions is met: the temperature is greater than a preset temperature, the current is greater than a preset current, the rotational speed is greater than a preset rotational speed, and the voltage is greater than a preset voltage.

[0061] Specifically, the system will enter a degraded state when at least one of the following conditions is met: temperature is greater than preset temperature (overheating), current is greater than preset current (overcurrent), speed is greater than preset speed (overspeed), and voltage is greater than preset voltage (overvoltage).

[0062] Optionally, determining the target torque based on the change value of the anomaly factor corresponding to the torque degradation condition includes:

[0063] The target torque is determined based on the change value, the degradation factor, and the required torque.

[0064] Specifically, in combination Figure 2 As shown, taking the overheating of the motor stator winding triggering degradation as an example, the actual temperature of the stator winding is T. act The temperature limit for triggering stator winding degradation is T. max The formula for calculating the target torque (or degraded torque) is:

[0065] T ini =p×(T) max -T act )×T req (3)

[0066] Among them, Tini T represents the target torque based on overtemperature. req This represents the required torque, which, under sufficient control precision, equals the actual torque. p represents the degradation factor, which makes p × (T) max -T act The value of ) is in the range [0, 1].

[0067] Optionally, determining the target torque based on the change value, the degradation factor, and the required torque includes:

[0068] The corresponding target torque calculation formula is determined based on the aforementioned anomaly factor.

[0069] Specifically, the target torque calculation formula is first determined based on the abnormal factors, such as the calculation formula (1) corresponding to the abnormal factor (temperature) mentioned above. The formulas corresponding to other abnormal factors can be derived from the formula (1) mentioned above.

[0070] Based on the target torque calculation formula, the target torque is determined according to the change value, the degradation coefficient, and the required torque.

[0071] Specifically, the target torque is determined by substituting the change value, degradation coefficient, and required torque into the target torque calculation formula corresponding to the corresponding anomaly factor.

[0072] Optionally, adjusting the target torque based on the friction torque and the load torque includes:

[0073] The vibration judgment value is determined based on the target torque, the friction torque, and the load torque.

[0074] Specifically, the vibration judgment value is determined based on the target torque, friction torque, and load torque, i.e.: (T ini -T b -T l ).

[0075] When the vibration determination value is within the preset range, the target torque is adjusted.

[0076] Specifically, in combination Figure 2 As shown, when the jitter judgment value (T) ini -T b -T l When it enters a specific preset range, adjust the target torque so that (T) ini -T b -T l It will not fluctuate near zero, thus not causing angular velocity fluctuations.

[0077] Optionally, adjusting the target torque when the vibration determination value is within a preset range includes:

[0078] When the jitter determination value is between the upper limit of jitter and the lower limit of jitter, the target torque is reduced.

[0079] Specifically, in combination Figure 2 As shown, since when the jitter judgment value (T) ini -T b -T l ) at the upper limit of jitter ΔT u and jitter lower limit ΔT l This will cause jitter when the time is between, therefore when the jitter judgment value (T) is between ini -T b -T l ) at the upper limit of jitter ΔT u and jitter lower limit ΔT l When in between, lower the target torque.

[0080] Optionally, adjusting the target torque when the vibration determination value is within a preset range further includes:

[0081] The reduction value of the target torque is determined based on the upper limit value of the jitter and the lower limit value of the jitter.

[0082] Specifically, the downward adjustment of the target torque is determined by the upper limit of the vibration ΔT. u and jitter lower limit ΔT l The target torque is determined by the downward adjustment value ΔT. e =ΔT u -ΔT l .

[0083] Optionally, adjusting the target torque based on the friction torque and the load torque further includes:

[0084] Based on the dynamic equations of the electric drive system, the load torque is determined according to the motor torque, motor speed, friction torque, and moment of inertia.

[0085] Specifically, the load torque can be determined by combining the above formula (2), and the details will not be repeated here.

[0086] Another embodiment of the present invention provides a vehicle including a computer-readable storage medium storing a computer program and a processor, wherein the computer program is read and executed by the processor to implement the above-described motor torque degradation control method.

[0087] Another embodiment of the present invention provides an electronic device, combined with Figure 3As shown, the electronic device includes a central processing unit (CPU) 301, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 302 or a program loaded from a storage section 308 into a random access memory (RAM) 303. The RAM 303 also stores various programs and data required for the operation of the electronic device. The CPU 301, ROM 302, and RAM 303 are interconnected via a bus 304. An input / output (I / O) interface 305 is also connected to the bus 304. In some embodiments, the following components are connected to the I / O interface 305: an input section 306 including a keyboard, mouse, etc.; an output section 307 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 308 including a hard disk, etc.; and a communication section 309 including a network interface card such as a LAN card, modem, etc. The communication section 309 performs communication processing via a network such as the Internet. A driver 310 is also connected to the I / O interface 305 as needed. Removable media 311, such as disks, optical disks, magneto-optical disks, semiconductor memories, etc., are mounted on drive 310 as needed so that computer programs read from them can be installed into storage section 308 as needed. In particular, according to embodiments of the invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the invention include a computer program product comprising a computer program carried on a machine-readable medium containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 309, and / or installed from removable media 311. When the computer program is executed by central processing unit (CPU) 301, the functions defined in the electronic device of the invention are performed.

[0088] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for motor torque degradation control, characterized in that, include: Monitor whether the torque degradation condition is triggered; When the torque degradation condition is triggered, the target torque is determined based on the change value of the abnormal factor corresponding to the torque degradation condition, and the target torque is adjusted according to the friction torque and load torque to avoid the target torque from fluctuating between the upper limit and lower limit of the jitter. The step of adjusting the target torque based on the friction torque and the load torque includes: The vibration determination value is determined based on the target torque, the friction torque, and the load torque; When the vibration determination value is within a preset range, adjust the target torque; Wherein, adjusting the target torque when the vibration determination value is within a preset range includes: When the jitter determination value is between the upper limit of jitter and the lower limit of jitter, the target torque is reduced; The step of adjusting the target torque when the vibration determination value is within a preset range further includes: The reduction value of the target torque is determined based on the upper limit value of the jitter and the lower limit value of the jitter.

2. The motor torque degradation control method according to claim 1, characterized in that, Whether the monitored torque degradation condition is triggered includes: Monitor whether the motor's temperature, current, speed, and voltage meet the triggering conditions for the corresponding torque degradation condition.

3. The motor torque degradation control method according to claim 2, characterized in that, The triggering conditions for monitoring whether the motor's temperature, current, speed, and voltage meet the corresponding torque degradation conditions include: The torque degradation condition is determined to be triggered when at least one of the following conditions is met: the temperature is greater than a preset temperature, the current is greater than a preset current, the rotational speed is greater than a preset rotational speed, and the voltage is greater than a preset voltage.

4. The motor torque degradation control method according to claim 1, characterized in that, Determining the target torque based on the change value of the anomaly factor corresponding to the torque degradation condition includes: The target torque is determined based on the change value, the degradation factor, and the required torque.

5. The motor torque degradation control method according to claim 4, characterized in that, Determining the target torque based on the change value, degradation factor, and required torque includes: The corresponding target torque calculation formula is determined based on the aforementioned anomaly factor; Based on the target torque calculation formula, the target torque is determined according to the change value, the degradation coefficient, and the required torque.

6. The motor torque degradation control method according to claim 1, characterized in that, The adjustment of the target torque based on the friction torque and the load torque further includes: Based on the dynamic equations of the electric drive system, the load torque is determined according to the motor torque, motor speed, friction torque, and moment of inertia.

7. A vehicle, characterized in that, The method includes a computer-readable storage medium storing a computer program and a processor, wherein the computer program is read and executed by the processor to implement the motor torque degradation control method as described in any one of claims 1 to 6.

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