Power battery parking heating locked-rotor protection method, vehicle controller and storage medium

Abstract

The invention provides a power battery parking heating locked-rotor protection method, a vehicle controller and a storage medium, and the method comprises the steps: obtaining the total heating heat damage of a motor before entering the current driving cycle parking heating, and judging whether the total heating heat damage of the motor is greater than a preset heat damage threshold value or not; if not, the motor is controlled to heat the power battery according to the normal heating current amplitude in the current driving circulating parking heating process; and if yes, the motor is controlled to heat the power battery according to the heating current amplitude obtained by derating the normal heating current amplitude in the current driving circulating parking heating process. According to the invention, the influence on the service life of the motor when the power battery is heated by the motor current can be effectively reduced, so that the reliability of the vehicle electric drive system is effectively enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and particularly to a method for protecting a power battery from overheating and stalling during parking heating, a vehicle controller, and a storage medium. Background Art

[0002] The current booming development of new energy vehicles has led to a large number of applications of lithium-ion-based power batteries. However, the performance of lithium batteries is greatly affected by temperature. In a low-temperature environment, the performance of power lithium batteries will deteriorate significantly, the charge and discharge capacity will decrease, and the working efficiency will be low, etc.

[0003] To improve the performance of vehicles used in cold regions, there are currently many technologies for heating power lithium batteries. For example, adjusting the D-axis current of the motor to generate heat in the motor winding to heat the battery coolant, and finally actively heating the power battery through the heated battery coolant. This method heats by increasing the magnitude of the stator current to increase the heat generated by the motor loss, but the DC heating current will cause the motor stator temperature to be relatively high. And when the vehicle is in a parked state, the motor loss is all used for heating, and the motor stator temperature rises faster. In addition, there is also a method of heating by alternating current. This method uses the motor inductance to generate a high-frequency alternating current to flow through the battery, and uses the internal resistance of the battery to generate heat to heat the battery. When heating the power battery, it uses the motor winding to access the three-phase inverter circuit connected to the power battery for charging and discharging cycles to excite the bus alternating current, thereby realizing the heating of the power battery. However, the disadvantage of this method is that a high-frequency large current flows through the motor winding, resulting in serious heating of the motor rotor and a rapid increase in the motor rotor temperature.

[0004] The above all use the motor current to heat the power battery, and these methods all have the problem that the temperature of the motor stator or rotor is too high during parking heating, which will reduce the motor life.

[0005] It should be noted that the information disclosed in the background art part of this invention is only intended to deepen the understanding of the general background art of the present invention, and should not be regarded as an admission or any form of suggestion that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for protecting a power battery from overheating and stalling during parking heating, a vehicle controller, and a storage medium, which can effectively reduce the impact on the motor life when heating the power battery through the motor current, thereby effectively enhancing the reliability of the vehicle electric drive system.

[0007] To achieve the above object, the present invention provides a method for protecting a power battery from overheating and stalling during parking heating, including: before entering the parking heating of the current driving cycle, obtaining the total heating thermal damage of the motor, and determining whether the total heating thermal damage of the motor is greater than a preset thermal damage threshold; if not, controlling the motor to heat the power battery according to the normal heating current amplitude during the parking heating of the current driving cycle; if so, controlling the motor to heat the power battery according to the heating current amplitude obtained by derating the normal heating current amplitude during the parking heating of the current driving cycle.

[0008] Optionally, the method for protecting a power battery from overheating and stalling during parking heating provided by the present invention further includes: obtaining the initial temperature of the motor when the parking heating of the current driving cycle is enabled, and continuously obtaining the temperature of the motor at each sampling moment during the parking heating of the current driving cycle; after exiting the parking heating of the current driving cycle, obtaining the temperature rise value of the motor during the parking heating of the current driving cycle according to the initial temperature of the motor and its highest temperature during the parking heating of the current driving cycle; obtaining the heating thermal damage of the motor during the parking heating of the current driving cycle according to the temperature rise value of the motor during the parking heating of the current driving cycle and the duration of the parking heating of the current driving cycle; and updating the total heating thermal damage of the motor according to the heating thermal damage of the motor during the parking heating of the current driving cycle.

[0009] Optionally, the step of obtaining the heating thermal damage of the motor during the parking heating of the current driving cycle according to the temperature rise value of the motor during the parking heating of the current driving cycle and the duration of the parking heating of the current driving cycle includes: querying in a pre-obtained mapping table of the heating thermal damage of the motor according to the temperature rise value of the motor during the parking heating of the current driving cycle and the duration of the parking heating of the current driving cycle, so as to obtain the heating thermal damage of the motor during the parking heating of the current driving cycle, wherein the mapping table of the heating thermal damage of the motor stores the mapping relationship between the heating thermal damage of the motor, the temperature rise value of the motor, and the duration of the parking heating.

[0010] Optionally, the total heating thermal damage of the motor includes at least one of the total DC current heating thermal damage and the total AC current heating thermal damage, wherein the total DC current heating thermal damage is the sum of the heating thermal damages of the stator of the motor from the first driving cycle parking DC current heating to the most recent driving cycle parking DC current heating, and the total AC current heating thermal damage is the sum of the heating thermal damages of the rotor of the motor from the first driving cycle parking AC current heating to the most recent driving cycle parking AC current heating; the preset thermal damage threshold includes at least one of the preset DC current heating thermal damage threshold and the preset AC current heating thermal damage threshold.

[0011] Optionally, for each driving cycle parking DC current heating, obtain the heating thermal damage of the stator of the motor during this driving cycle parking DC current heating according to the temperature rise value of the stator of the motor during this driving cycle parking DC current heating and the duration of this driving cycle parking DC current heating; for each driving cycle parking AC current heating, obtain the heating thermal damage of the rotor of the motor during this driving cycle parking AC current heating according to the temperature rise value of the rotor of the motor during this driving cycle parking AC current heating and the duration of this driving cycle parking AC current heating.

[0012] Optionally, the step of obtaining the heating thermal damage of the stator of the motor during this driving cycle parking DC current heating according to the temperature rise value of the stator of the motor during this driving cycle parking DC current heating and the duration of this driving cycle parking DC current heating includes: for each driving cycle parking DC current heating, query in the pre-obtained mapping table of the heating thermal damage of the motor stator according to the temperature rise value of the stator of the motor during this driving cycle parking DC current heating and the duration of this driving cycle parking DC current heating, so as to obtain the heating thermal damage of the stator of the motor during this driving cycle parking DC current heating, wherein the mapping table of the heating thermal damage of the motor stator stores the mapping relationship between the heating thermal damage of the motor stator, the temperature rise value of the motor stator, and the duration of the parking DC current heating.

[0013] Optionally, the step of obtaining the heating thermal damage of the rotor of the motor during this driving cycle parking AC current heating according to the temperature rise value of the rotor of the motor during this driving cycle parking AC current heating and the duration of this driving cycle parking AC current heating includes: for each driving cycle parking AC current heating, query in the pre-obtained mapping table of the heating thermal damage of the motor rotor according to the temperature rise value of the rotor of the motor during this driving cycle parking AC current heating and the duration of this driving cycle parking AC current heating, so as to obtain the heating thermal damage of the rotor of the motor during this driving cycle parking AC current heating, wherein the mapping table of the heating thermal damage of the motor rotor stores the mapping relationship between the heating thermal damage of the motor rotor, the temperature rise value of the motor rotor, and the duration of the parking AC current heating.

[0014] Optionally, controlling the motor to heat the power battery with the heating current amplitude obtained by derating the normal heating current amplitude during the current driving cycle parking heating includes: If the current driving cycle parking heating adopts the DC current heating mode, controlling the motor to derate the normal heating current amplitude according to the real-time temperature of the stator of the motor during the current driving cycle parking heating, and heating the power battery with the heating current amplitude obtained by the derating process; If the current driving cycle parking heating adopts the AC current heating mode, controlling the motor to derate the normal heating current amplitude according to the real-time temperature of the rotor of the motor during the current driving cycle parking heating, and heating the power battery with the heating current amplitude obtained by the derating process.

[0015] To achieve the above object, the present invention also provides a vehicle controller, including a processor and a memory, with a computer program stored on the memory. When the computer program is executed by the processor, the power battery parking heating lock-rotor protection method described above is implemented.

[0016] To achieve the above object, the present invention also provides a readable storage medium, with a computer program stored therein. When the computer program is executed by a processor, the power battery parking heating lock-rotor protection method described above is implemented.

[0017] Compared with the prior art, the power battery parking heating lock-rotor protection method, vehicle controller, and storage medium provided by the present invention have the following beneficial effects:

[0018] The power battery parking heating lock-rotor protection method provided by the present invention first obtains the total heating thermal damage of the motor before entering the current driving cycle parking heating, and then determines whether the total heating thermal damage of the motor is greater than a preset thermal damage threshold; If the total heating thermal damage of the motor is less than or equal to the preset thermal damage threshold, controlling the motor to heat the power battery with the normal heating current amplitude during the current driving cycle parking heating; If the total heating thermal damage of the motor is greater than the preset thermal damage threshold, controlling the motor to heat the power battery with the heating current amplitude obtained by derating the normal heating current amplitude during the current driving cycle parking heating. Thus, it can be seen that by adopting the power battery parking heating lock-rotor protection method provided by the present invention, not only can the impact on the motor life caused by heating the power battery through the motor current be effectively reduced, thereby effectively enhancing the reliability of the vehicle electric drive system, but also the heating efficiency can be maximized while protecting the motor, improving the heating effect of the power battery.

[0019] Since the vehicle controller and readable storage medium provided by the present invention and the power battery parking heating locked-rotor protection method provided by the present invention belong to the same inventive concept, the vehicle controller and readable storage medium provided by the present invention at least have all the beneficial effects of the power battery parking heating locked-rotor protection method provided by the present invention. For specific details, reference can be made to the relevant descriptions in the above text. Therefore, the beneficial effects of the vehicle controller and readable storage medium provided by the present invention will not be elaborated one by one herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flowchart of the power battery parking heating locked-rotor protection method provided by an embodiment of the present invention;

[0021] Figure 2 It is an overall flowchart of the power battery parking heating locked-rotor protection method provided by an embodiment of the present invention;

[0022] Figure 3 It is a schematic block diagram of a vehicle controller provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The power battery parking heating locked-rotor protection method, vehicle controller and storage medium proposed by the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and all use non-precise scales, only for the convenience of clearly assisting in explaining the purpose provided by the present invention. In order to make the purpose, features and advantages of the present invention more obvious and understandable, please refer to the accompanying drawings. It should be noted that the structures, scales, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions of the implementation of the present invention. Any modification of the structure, change of the proportional relationship or adjustment of the size, under the condition of being the same or approximate to the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope covered by the technical content disclosed by the present invention.

[0024] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element. The singular forms "a", "an" and "the" include plural referents, the term "or" is generally used in the sense of "and / or", the term "several" is generally used in the sense of "at least one", the term "at least two" is generally used in the sense of "two or more", and in addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features.

[0025] In addition, in the description of this specification, descriptions with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0026] For the convenience of understanding, the research background of the present invention will be briefly described first.

[0027] The temperature rise of the motor will affect the motor performance. For the permanent magnet of the permanent magnet synchronous motor used in the electric drive system, the increase in the rotor temperature will cause the magnetic flux density to decrease, resulting in a reduction in the rotor torque and the resulting efficiency response, and even affecting the insulation life and leading to insulation failure. The stator temperature is limited by the motor enameled wire, and serious thermal aging will affect the life of the enameled wire, resulting in cracking of the enameled wire, etc. The loss generated by the motor current during parking is used for heating, causing the temperature of the motor stator or rotor to rise, thus having a greater impact on the motor life.

[0028] Based on this, the core idea of the present invention is to provide a method for protecting a power battery from overheating and stalling during parking, a vehicle controller, and a storage medium. By statistically analyzing the heating thermal damage caused to the motor (electric drive system) throughout the entire life cycle of the motor, it is possible to achieve overheating and stalling protection for the power battery during parking, reduce the impact on the motor life when heating the power battery through the motor current, and enhance the reliability of the vehicle's electric drive system.

[0029] It should be noted that the method for protecting a power battery from overheating and stalling during parking provided by the present invention can be applied to the vehicle controller provided by the present invention. The vehicle controller can be configured on a vehicle, and the vehicle controller can be a hardware device with various operating systems. The vehicle can include general motor vehicles, such as passenger vehicles including sports utility vehicles (SUVs), buses, trucks, and various commercial vehicles, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, etc. In addition, it should be noted that as understood by those skilled in the art, the "heating with direct current during driving cycle parking" referred to in the present invention means heating during driving cycle parking using a direct current heating mode, and the "heating with alternating current during driving cycle parking" referred to in the present invention means heating during driving cycle parking using an alternating current heating mode. Additionally, it should be noted that as understood by those skilled in the art, the "heating thermal damage" referred to in the present invention means the cumulative effect of material property degradation and life attenuation caused by the temperature rise of the stator or rotor during the parking heating process of the motor. Its core connotation is to evaluate the consumption of the overall life of the motor by quantifying the damage degree of temperature and time to key components of the motor (such as permanent magnets and insulating materials).

[0030] To achieve the above idea, the present invention provides a method for protecting a power battery from overheating and stalling during parking. Please refer to Figure 1 , which is a flowchart of the method for protecting a power battery from overheating and stalling during parking provided by an embodiment of the present invention. As shown in Figure 1 , the method for protecting a power battery from overheating and stalling during parking includes the following steps: Step S100: Before entering the current driving cycle parking heating, obtain the total heating thermal damage of the motor, and determine whether the total heating thermal damage of the motor is greater than a preset thermal damage threshold; if the total heating thermal damage of the motor is less than or equal to the preset thermal damage threshold, then execute Step S200; Step S200: Control the motor to heat the power battery at the normal heating current amplitude during the current driving cycle parking heating; if the total heating thermal damage of the motor is greater than the preset thermal damage threshold, then execute Step S300; Step S300: Control the motor to heat the power battery at the heating current amplitude obtained by derating the normal heating current amplitude during the current driving cycle parking heating.

[0031] Thus, when the total heating thermal damage of the motor is less than or equal to the preset thermal damage threshold, the motor is controlled to heat the power battery according to the normal heating current amplitude. When the total heating thermal damage of the motor is greater than the preset thermal damage threshold, the motor is controlled to heat the power battery according to the heating current amplitude obtained by derating the normal heating current amplitude. This can not only effectively reduce the impact on the motor life when heating the power battery through the motor current, thereby effectively enhancing the reliability of the vehicle electric drive system, but also maximize the heating efficiency while protecting the motor and improve the heating effect of the power battery.

[0032] It should be noted that, as can be understood by those skilled in the art, if the current driving cycle parking heating is the first driving cycle parking heating in the entire life cycle of the motor, then before entering the current driving cycle parking heating, the total heating thermal damage of the motor is 0. It should also be noted that, as can be understood by those skilled in the art, the present invention does not limit the specific value of the preset thermal damage threshold, and the preset thermal damage threshold can be determined according to factors such as the service life of the motor.

[0033] In some exemplary embodiments, the total heating thermal damage of the motor includes at least one of the total DC current heating thermal damage and the total AC current heating thermal damage. Among them, the total DC current heating thermal damage is the sum of the heating thermal damages of the stator of the motor from the first driving cycle parking DC current heating to the most recent driving cycle parking DC current heating, and the total AC current heating thermal damage is the sum of the heating thermal damages of the rotor of the motor from the first driving cycle parking AC current heating to the most recent driving cycle parking AC current heating; the preset thermal damage threshold includes at least one of the preset DC current heating thermal damage threshold and the preset AC current heating thermal damage threshold.

[0034] Since DC current heating mainly affects the stator and AC current heating mainly affects the rotor, by separately counting the DC current heating thermal damage and the AC current heating thermal damage, it is possible to accurately track the independent damages of the two parking heating methods to the stator and the rotor, and avoid the failure of the protection strategy caused by mixed statistics; since the temperature resistance thresholds of the stator enameled wire and the rotor permanent magnet are different, by separately setting the DC current heating thermal damage threshold and the AC current heating thermal damage threshold, differential protection standards can be formulated according to material characteristics (such as the heat resistance grade of the enameled wire and the Curie temperature of the permanent magnet), and avoid overprotection or underprotection caused by a single threshold. In summary, by separately counting the DC current heating thermal damage and the AC current heating thermal damage and separately setting the corresponding thresholds, the present invention can distinguish the differential effects of the heating methods on the stator and the rotor, achieve more scientific thermal damage accumulation, more accurate life protection, and more flexible derating control, and ultimately improve the reliability and service life of the electric drive system (motor).

[0035] Specifically, if the parking heating in the current driving cycle uses direct current heating, the total direct current heating thermal damage of the motor can be obtained before enabling the parking heating, and it is determined whether the total direct current heating thermal damage of the motor is greater than the preset direct current heating thermal damage threshold. If the total direct current heating thermal damage of the motor is less than or equal to the preset direct current heating thermal damage threshold, the electric drive system can perform normal parking heating (i.e., the motor heats the power battery according to the normal heating current amplitude). If the total direct current heating thermal damage of the motor is greater than the preset direct current heating thermal damage threshold, the current amplitude during normal heating is derated to reduce the impact of heating on the motor life. If the parking heating in the current driving cycle uses alternating current heating, the total alternating current heating thermal damage of the motor can be obtained before enabling the parking heating, and it is determined whether the total alternating current heating thermal damage of the motor is greater than the preset alternating current heating thermal damage threshold. If the total alternating current heating thermal damage of the motor is less than or equal to the preset alternating current heating thermal damage threshold, the electric drive system can perform normal parking heating (i.e., the motor heats the power battery according to the normal heating current amplitude). If the total alternating current heating thermal damage of the motor is greater than the preset alternating current heating thermal damage threshold, the current amplitude during normal heating is derated to reduce the impact of heating on the motor life.

[0036] It should be noted that, as can be understood by those skilled in the art, the present invention does not limit the specific values of the preset direct current heating thermal damage threshold and the preset alternating current heating thermal damage threshold. The preset direct current heating thermal damage threshold can be determined according to factors such as the service life of the stator of the motor, and the preset alternating current heating thermal damage threshold can be determined according to factors such as the service life of the rotor of the motor.

[0037] In some exemplary embodiments, for each parking direct current heating in a driving cycle, according to the temperature rise value of the stator of the motor during the parking direct current heating in this driving cycle and the duration of the parking direct current heating in this driving cycle, the heating thermal damage of the stator of the motor during the parking direct current heating in this driving cycle is obtained; for each parking alternating current heating in a driving cycle, according to the temperature rise value of the rotor of the motor during the parking alternating current heating in this driving cycle and the duration of the parking alternating current heating in this driving cycle, the heating thermal damage of the rotor of the motor during the parking alternating current heating in this driving cycle is obtained.

[0038] The aging rate of the stator enameled wire caused by parking DC current heating is usually related to the temperature rise and heating time. Therefore, for each driving cycle's parking DC current heating, based on the temperature rise value of the motor's stator during this driving cycle's parking DC current heating and the duration of this driving cycle's parking DC current heating, the heating thermal damage of the motor's stator during this driving cycle's parking DC current heating can be accurately obtained. Similarly, the aging rate of the rotor permanent magnet caused by parking AC current heating is usually related to the temperature rise and heating time. Therefore, for each driving cycle's parking AC current heating, based on the temperature rise value of the motor's rotor during this driving cycle's parking AC current heating and the duration of this driving cycle's parking AC current heating, the heating thermal damage of the motor's rotor during this driving cycle's parking AC current heating can be accurately obtained.

[0039] In some exemplary embodiments, for each driving cycle's parking DC current heating, based on the temperature rise value of the motor's stator during this driving cycle's parking DC current heating and the duration of this driving cycle's parking DC current heating, obtaining the heating thermal damage of the motor's stator during this driving cycle's parking DC current heating includes: for each driving cycle's parking DC current heating, based on the temperature rise value of the motor's stator during this driving cycle's parking DC current heating and the duration of this driving cycle's parking DC current heating, querying in a pre-obtained mapping table of the heating thermal damage of the motor stator to obtain the heating thermal damage of the motor's stator during this driving cycle's parking DC current heating, wherein the mapping table of the heating thermal damage of the motor stator stores the mapping relationship between the heating thermal damage of the motor stator and the temperature rise value of the motor stator and the duration of the parking DC current heating.

[0040] Thus, for each driving cycle's parking DC current heating, by determining the heating thermal damage of the motor stator by looking up the table according to the temperature rise value of the motor stator and the duration of the parking DC current heating, the accuracy of the obtained heating thermal damage of the motor stator can be further ensured. It should be noted that, as can be understood by those skilled in the art, the mapping table of the heating thermal damage of the motor stator can be obtained through experimental calibration. It should also be noted that, as can be understood by those skilled in the art, for each driving cycle's parking DC current heating, the temperature rise value of the motor stator during this driving cycle's parking DC current heating refers to the difference between the highest temperature and the initial temperature of the motor stator during this driving cycle's parking DC current heating.

[0041] In some exemplary embodiments, for each driving cycle's parking alternating current heating, obtaining the heating thermal damage of the rotor of the motor during this driving cycle's parking alternating current heating according to the temperature rise value of the rotor of the motor during this driving cycle's parking alternating current heating and the duration of this driving cycle's parking alternating current heating includes: for each driving cycle's parking alternating current heating, querying in a pre-obtained mapping table of the heating thermal damage of the motor rotor according to the temperature rise value of the rotor of the motor during this driving cycle's parking alternating current heating and the duration of this driving cycle's parking alternating current heating, so as to obtain the heating thermal damage of the rotor of the motor during this driving cycle's parking alternating current heating, wherein the mapping table of the heating thermal damage of the motor rotor stores the mapping relationship between the heating thermal damage of the motor rotor, the temperature rise value of the motor rotor, and the duration of the parking alternating current heating.

[0042] Thus, for each driving cycle's parking alternating current heating, by determining the heating thermal damage of the motor rotor by looking up the table according to the temperature rise value of the motor rotor and the duration of the parking alternating current heating, the accuracy of the obtained heating thermal damage of the motor rotor can be further ensured. It should be noted that, as can be understood by those skilled in the art, the mapping table of the heating thermal damage of the motor rotor can be obtained through experimental calibration. It should be noted that, as can be understood by those skilled in the art, for each driving cycle's parking alternating current heating, the temperature rise value of the rotor of the motor during this driving cycle's parking alternating current heating refers to the difference between the highest temperature and the initial temperature of the rotor of the motor during this driving cycle's parking alternating current heating.

[0043] In some exemplary embodiments, controlling the motor to heat the power battery with a heating current amplitude obtained by derating the normal heating current amplitude during the current driving cycle's parking heating includes: if the current driving cycle's parking heating adopts a direct current heating mode, controlling the motor to derate the normal heating current amplitude according to the real-time temperature of the stator of the motor during the current driving cycle's parking heating, and heating the power battery with the heating current amplitude obtained by the derating process; if the current driving cycle's parking heating adopts an alternating current heating mode, controlling the motor to derate the normal heating current amplitude according to the real-time temperature of the rotor of the motor during the current driving cycle's parking heating, and heating the power battery with the heating current amplitude obtained by the derating process.

[0044] Thus, such a setting can quickly adjust the current amplitude according to the real-time temperatures of the stator and the rotor, avoid the stator and the rotor from being in the high-temperature range for a long time, reduce the accumulation of thermal fatigue of the stator and the rotor, delay the aging of the stator insulation and the attenuation of the rotor magnetic performance, so that not only the service life of the motor can be extended, but also the safety and user experience under complex working conditions can be improved.

[0045] In some exemplary embodiments, the power battery parking heating and locked-rotor protection method provided by the present invention further includes: obtaining the initial temperature of the motor when parking heating is enabled in the current driving cycle, and obtaining the temperature of the motor at each sampling moment during parking heating in the current driving cycle in real time; after exiting the parking heating in the current driving cycle, obtaining the temperature rise value of the motor during parking heating in the current driving cycle according to the initial temperature of the motor and its highest temperature during parking heating in the current driving cycle; obtaining the heating thermal damage of the motor during parking heating in the current driving cycle according to the temperature rise value of the motor during parking heating in the current driving cycle and the duration of parking heating in the current driving cycle; and updating the total heating thermal damage of the motor according to the heating thermal damage of the motor during parking heating in the current driving cycle.

[0046] Specifically, if the parking heating in the current driving cycle adopts the DC current heating mode, the initial temperature of the stator of the motor when the parking heating in the current driving cycle is enabled can be obtained, and the temperature of the stator of the motor at each sampling moment during the parking heating in the current driving cycle can be obtained in real time. After exiting the parking heating in the current driving cycle, according to the initial temperature of the stator of the motor and its highest temperature during the parking heating in the current driving cycle, the temperature rise value of the stator of the motor during the parking heating in the current driving cycle is obtained. According to the temperature rise value of the stator of the motor during the parking heating in the current driving cycle and the duration of the parking heating in the current driving cycle, the heating thermal damage of the stator of the motor during the parking heating in the current driving cycle is obtained; according to the heating thermal damage of the stator of the motor during the parking heating in the current driving cycle, the total DC current heating thermal damage of the motor is updated. If the parking heating in the current driving cycle adopts the AC current heating mode, the initial temperature of the rotor of the motor when the parking heating in the current driving cycle is enabled can be obtained, and the temperature of the rotor of the motor at each sampling moment during the parking heating in the current driving cycle can be obtained in real time. After exiting the parking heating in the current driving cycle, according to the initial temperature of the rotor of the motor and its highest temperature during the parking heating in the current driving cycle, the temperature rise value of the rotor of the motor during the parking heating in the current driving cycle is obtained. According to the temperature rise value of the rotor of the motor during the parking heating in the current driving cycle and the duration of the parking heating in the current driving cycle, the heating thermal damage of the rotor of the motor during the parking heating in the current driving cycle is obtained; according to the heating thermal damage of the rotor of the motor during the parking heating in the current driving cycle, the total AC current heating thermal damage of the motor is updated.

[0047] In some exemplary embodiments, obtaining the heating thermal damage of the motor during the parking heating in the current driving cycle according to the temperature rise value of the motor during the parking heating in the current driving cycle and the duration of the parking heating in the current driving cycle includes: querying in a pre-obtained motor heating thermal damage mapping table according to the temperature rise value of the motor during the parking heating in the current driving cycle and the duration of the parking heating in the current driving cycle to obtain the heating thermal damage of the motor during the parking heating in the current driving cycle, wherein the heating thermal damage mapping table stores the mapping relationship between the heating thermal damage of the motor, the temperature rise value of the motor, and the duration of the parking heating.

[0048] Specifically, if the parking heating in the current driving cycle adopts the DC current heating mode, then according to the temperature rise value of the stator of the motor during the parking heating in the current driving cycle and the duration of the parking heating in the current driving cycle, query in the pre-obtained motor stator heating thermal damage mapping table to obtain the heating thermal damage of the stator of the motor during the parking heating in the current driving cycle. If the parking heating in the current driving cycle adopts the AC current heating mode, then according to the temperature rise value of the rotor of the motor during the parking heating in the current driving cycle and the duration of the parking heating in the current driving cycle, query in the pre-obtained motor rotor heating thermal damage mapping table to obtain the heating thermal damage of the rotor of the motor during the parking heating in the current driving cycle.

[0049] Please continue to refer to Figure 2 , which is the overall flowchart of the power battery parking heating locked-rotor protection method provided by an embodiment of the present invention. As Figure 2 shown, the power battery parking heating locked-rotor protection method provided by the present invention specifically includes the following steps:

[0050] 1) Determine whether the parking heating is enabled. When enabled, record the initial temperature T0 at the moment when the electric drive system enters the parking heating (if DC current heating is adopted, record the initial temperature of the motor stator; if AC current heating is adopted, record the initial temperature of the motor rotor).

[0051] 2) During the parking heating process, collect the temperature value at each moment (if DC current heating is adopted, it is the temperature value of the motor stator; if AC current heating is adopted, it is the temperature value of the motor rotor), and take the maximum value among them to obtain the highest temperature value T max (if DC current heating is adopted, it is the highest temperature value of the motor stator; if AC current heating is adopted, it is the highest temperature value of the motor rotor).

[0052] 3) After exiting the parking heating, according to the initial temperature T0 and the highest temperature T max , calculate the temperature rise value ΔT = T max - T0.

[0053] 4) According to the calibration table obtained from experimental tests (if DC current heating is adopted, it is the motor stator heating thermal damage mapping table; if AC current heating is adopted, it is the motor rotor heating thermal damage mapping table), obtain the heating thermal damage ΔX by looking up the table with the temperature rise value ΔT and the heating time t of this time (if DC current heating is adopted, it is the heating thermal damage of the motor stator; if AC current heating is adopted, it is the heating thermal damage of the motor rotor).

[0054] Although the impact of the temperature rise of the parking heating motor stator and rotor on the motor life accumulates in each driving cycle, since the parts of the motor affected by the temperature rise of the stator and rotor are different, it is necessary to count and set thresholds separately for DC current heating and AC current heating. When the electric drive system is powered off, the total DC current heating thermal damage value of the first driving cycle parking DC current heating to the current driving cycle parking DC current heating / the total AC current heating thermal damage value of the first driving cycle parking AC current heating to the current driving cycle parking AC current heating will be stored in the memory (such as EEPROM, Electrically Erasable Programmable Read-Only Memory). When the power is turned on again and enters the next driving cycle, the MCU (Microcontroller Unit) reads the cumulative heating total thermal damage X i-1,sum (If DC current heating is used, it is the total DC current heating thermal damage; if AC current heating is used, it is the total AC current heating thermal damage) from the memory.

[0055] 5) According to the parking heating thermal damage ΔX obtained in step 4) (if DC current heating is used, it is the heating thermal damage of the motor stator; if AC current heating is used, it is the heating thermal damage of the motor rotor), according to the following formula (1), the new cumulative parking heating total thermal damage X i,sum (If DC current heating is used, it is the total DC current heating thermal damage; if AC current heating is used, it is the total AC current heating thermal damage) of the electric drive system is obtained and stored in the memory such as EEPROM (Electrically Erasable Programmable Read-Only Memory), waiting to be read when the next driving cycle is powered on (i.e., the current X i,sum becomes the X of the next driving cycle i-1,sum ).

[0056] X i,sum =X i-1,sum +ΔX (1)

[0057] 6) Before each entry into parking heating, that is, before step 1) is performed, it is necessary to judge whether the cumulative parking heating total thermal damage X i-1,sum (If DC current heating is used, it is the total DC current heating thermal damage; if AC current heating is used, it is the total AC current heating thermal damage) of the electric drive system exceeds the preset heating thermal damage threshold X max (If DC current heating is used, it is the preset DC current heating thermal damage threshold; if AC current heating is used, it is the preset AC current heating thermal damage threshold). If the cumulative total thermal damage value does not exceed the threshold, the electric drive system can perform normal parking heating; if the cumulative total thermal damage value exceeds the threshold X max, the amplitude of the heating current during normal heating is derated according to the stator temperature or rotor temperature of the motor (if DC current heating is used, it is the stator temperature; if AC current heating is used, it is the rotor temperature) to reduce the impact of heating on the motor life.

[0058] Based on the same inventive concept, the present invention also provides a vehicle controller. Please refer to Figure 3 , which is a schematic block diagram of the vehicle controller provided by an embodiment of the present invention. As Figure 3 shown, the vehicle controller includes a processor 101 and a memory 103. A computer program is stored on the memory 103. When the computer program is executed by the processor 101, the power battery parking heating locked-rotor protection method described above is implemented. Since the vehicle controller provided by the present invention and the power battery parking heating locked-rotor protection method provided by the present invention belong to the same inventive concept, the vehicle controller provided by the present invention has at least all the beneficial effects of the power battery parking heating locked-rotor protection method provided by the present invention. For details, reference can be made to the relevant descriptions above. Therefore, the beneficial effects of the vehicle controller provided by the present invention will not be elaborated one by one here.

[0059] As Figure 3 shown, the vehicle controller further includes a communication interface 102 and a communication bus 104. Among them, the processor 101, the communication interface 102, and the memory 103 complete communication with each other through the communication bus 104. The communication bus 104 includes but is not limited to a CAN bus, etc. For the sake of convenience of representation, only a thick line is used in the figure, but it does not mean that there is only one bus or one type of bus. The communication interface 102 is used for communication between the above vehicle controller (such as a motor controller) and other vehicle controllers (such as a vehicle controller, a battery management controller, etc., not shown in the figure). The communication bus 104 connects the above vehicle controller (such as a motor controller) and other vehicle controllers (such as a vehicle controller, a battery management controller, etc., not shown in the figure) and other scattered nodes into a closed-loop system, enabling each vehicle controller to perform communication and data transmission in multiple working states (parking state, charging state, starting state, running state, vehicle forward and reverse states, feedback braking state, mechanical braking state, general fault state, major fault state), so as to realize the control function of the vehicle.

[0060] The processor 101 mentioned in the present invention may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The processor 101 is the control center of the vehicle controller, and connects various parts of the entire vehicle controller through various interfaces and lines.

[0061] The memory 103 can be used to store the computer program. The processor 101 realizes various functions of the vehicle controller by running or executing the computer program stored in the memory 103 and calling the data stored in the memory 103. The memory 103 may include non-volatile and / or volatile memory. The non-volatile memory may include read-only memory (ROM), programmable memory (PROM), electrically programmable memory (EPROM), electrically erasable programmable memory (EEPROM), or flash memory. The volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, random access memory is available in many forms, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous random access memory (SDRAM), double data rate synchronous random access memory (DDR SDRAM), enhanced synchronous random access memory (ESDRAM), synchronous link (Synchlink) dynamic random access memory (SLDRAM), memory bus (Rambus) direct random access memory (RDRAM), direct memory bus dynamic random access memory (DRDRAM), and memory bus dynamic random access memory (RDRAM), etc.

[0062] The present invention also provides a readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the power battery parking heating locked-rotor protection method described above can be implemented. Since the readable storage medium provided by the present invention and the power battery parking heating locked-rotor protection method provided by the present invention belong to the same inventive concept, the readable storage medium provided by the present invention has at least all the beneficial effects of the power battery parking heating locked-rotor protection method provided by the present invention. For specific details, reference can be made to the relevant descriptions above. Therefore, the beneficial effects of the readable storage medium provided by the present invention will not be elaborated one by one here.

[0063] It should be noted that the readable storage medium provided by the present invention can adopt any combination of one or more computer-readable media. The readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples (non-exhaustive list) of the computer-readable storage medium include: an electrical connection with one or more wires, a portable computer hard disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, the computer-readable storage medium can be any tangible medium that contains or stores a program, and this program can be used by or in combination with an instruction execution system, apparatus, or device.

[0064] Furthermore, the computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, in which the computer-readable program code is carried. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, and this computer-readable medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted by any appropriate medium, including but not limited to wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0065] In summary, compared with the prior art, the power battery parking heating locked-rotor protection method, vehicle controller, and storage medium provided by the present invention have the following beneficial effects:

[0066] Before entering the parking heating in the current driving cycle, the present invention first obtains the total heating thermal damage of the motor, and then determines whether the total heating thermal damage of the motor is greater than a preset thermal damage threshold; if the total heating thermal damage of the motor is less than or equal to the preset thermal damage threshold, the motor is controlled to heat the power battery according to the normal heating current amplitude during the parking heating in the current driving cycle; if the total heating thermal damage of the motor is greater than the preset thermal damage threshold, the motor is controlled to heat the power battery according to the heating current amplitude obtained by derating the normal heating current amplitude during the parking heating in the current driving cycle. Thereby, not only can the influence on the motor life caused by heating the power battery through the motor current be effectively reduced, thus effectively enhancing the reliability of the vehicle electric drive system, but also the heating efficiency can be maximized while protecting the motor, and the heating effect of the power battery can be improved.

[0067] It should be noted that computer program code for performing the operations of the present invention can be written in one or more programming languages or combinations thereof. The programming languages include object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, by using an Internet service provider to connect through the Internet).

[0068] It should be noted that the devices and methods disclosed in the embodiments of this article can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of devices, methods, and computer program products according to multiple embodiments of this article. In this regard, each block in the flowchart or block diagram may represent a module, program, or part of the code, and the module, program segment, or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, as well as the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions. Additionally, in the various embodiments of this article, the functional modules can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0069] It should also be noted that the above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure belong to the protection scope of the present invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations fall within the scope of the present invention and its equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A method for protecting a power battery from parking, heating and stalling, characterized in that: include: Before entering the parking heating of the current driving cycle, obtaining the total heating thermal damage of the motor, and determining whether the total heating thermal damage of the motor is greater than a preset thermal damage threshold; If not, controlling the motor to heat the power battery according to a normal heating current amplitude in the parking heating of the current driving cycle; If so, the motor is controlled to heat the power battery according to the heating current amplitude obtained by derating the normal heating current amplitude during parking heating in the current driving cycle.

2. The power battery parking heating and stall protection method according to claim 1, characterized in that: The method further comprises: Acquire the initial temperature of the motor when parking heating is enabled in the current driving cycle, and acquire the temperature of the motor at each sampling moment in the parking heating in the current driving cycle in real time; After exiting the parking heating in the current driving cycle, obtaining a temperature rise value of the motor in the parking heating in the current driving cycle according to the initial temperature of the motor and the highest temperature of the motor in the parking heating in the current driving cycle; Obtaining heating thermal damage of the motor in the current driving cycle parking heating according to a temperature rise value of the motor in the current driving cycle parking heating and a duration of the current driving cycle parking heating; According to the heating thermal damage of the motor in parking heating in the current driving cycle, the total heating thermal damage of the motor is updated.

3. The power battery parking heating and stall protection method according to claim 2, characterized in that: The step of obtaining the heating thermal damage of the motor in the current driving cycle parking heating according to the temperature rise value of the motor in the current driving cycle parking heating and the duration of the current driving cycle parking heating includes: According to the temperature rise value of the motor in the parking heating of the current driving cycle and the duration of the parking heating of the current driving cycle, a query is performed in a pre-acquired motor heating thermal damage mapping table to obtain the heating thermal damage of the motor in the parking heating of the current driving cycle, wherein the heating thermal damage mapping table stores a mapping relationship between the heating thermal damage of the motor and the temperature rise value of the motor and the duration of the parking heating.

4. The power battery parking heating and stall protection method according to claim 1, characterized in that: The total heating thermal damage of the motor includes at least one of total DC current heating thermal damage and total AC current heating thermal damage, wherein the total DC current heating thermal damage is the sum of heating thermal damages of the stator of the motor from the first driving cycle parking DC current heating to the most recent driving cycle parking DC current heating, and the total AC current heating thermal damage is the sum of heating thermal damages of the rotor of the motor from the first driving cycle parking AC current heating to the most recent driving cycle parking AC current heating; The preset thermal damage threshold includes at least one of a preset direct current heating thermal damage threshold and a preset alternating current heating thermal damage threshold.

5. The power battery parking heating and stall protection method according to claim 4, characterized in that: For each driving cycle parking DC current heating, according to the temperature rise value of the stator of the motor in the driving cycle parking DC current heating and the duration of the driving cycle parking DC current heating, the heating thermal damage of the stator of the motor in the driving cycle parking DC current heating is obtained; For each driving cycle parking AC current heating, the heating thermal damage of the rotor of the motor during this driving cycle parking AC current heating is obtained according to the temperature rise value of the rotor of the motor during this driving cycle parking AC current heating and the duration of this driving cycle parking AC current heating.

6. The power battery parking heating and stall protection method according to claim 5, characterized in that: The step of obtaining the heating thermal damage of the stator of the motor during the driving cycle parking DC current heating according to the temperature rise value of the stator of the motor during the driving cycle parking DC current heating and the duration of the driving cycle parking DC current heating for each driving cycle parking DC current heating comprises: For each driving cycle parking DC current heating, according to the temperature rise value of the stator of the motor in the driving cycle parking DC current heating and the duration of the driving cycle parking DC current heating, a query is performed in a pre-acquired motor stator heating thermal damage mapping table to obtain the heating thermal damage of the stator of the motor in the driving cycle parking DC current heating, wherein the motor stator heating thermal damage mapping table stores a mapping relationship between the heating thermal damage of the motor stator and the temperature rise value of the motor stator and the duration of the parking DC current heating.

7. The power battery parking heating and stall protection method according to claim 5, characterized in that: The step of obtaining the heating heat damage of the rotor of the motor during the driving cycle parking AC current heating according to the temperature rise value of the rotor of the motor during the driving cycle parking AC current heating and the duration of the driving cycle parking AC current heating for each driving cycle parking AC current heating comprises: For each driving cycle parking AC current heating, according to the temperature rise value of the rotor of the motor in the driving cycle parking AC current heating and the duration of the driving cycle parking AC current heating, a query is performed in a pre-acquired motor rotor heating thermal damage mapping table to obtain the heating thermal damage of the rotor of the motor in the driving cycle parking AC current heating, wherein the motor rotor heating thermal damage mapping table stores a mapping relationship between the heating thermal damage of the motor rotor and the temperature rise value of the motor rotor and the duration of the parking AC current heating.

8. The power battery parking heating and stall protection method according to claim 4, characterized in that: The controlling the motor to heat the power battery according to a heating current amplitude obtained by de-rating a normal heating current amplitude during parking heating in the current driving cycle includes: If the parking heating in the current driving cycle adopts the DC current heating mode, the motor is controlled to derate the normal heating current amplitude according to the real-time temperature of the stator of the motor in the parking heating in the current driving cycle, and the power battery is heated according to the heating current amplitude obtained by the derated processing; If the current driving cycle parking heating adopts the AC current heating mode, the motor is controlled to derate the normal heating current amplitude according to the real-time temperature of the rotor of the motor during the current driving cycle parking heating, and the power battery is heated according to the heating current amplitude obtained by the derated processing.

9. A vehicle controller, characterized in that: The invention comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the power battery parking heating and stall protection method according to any one of claims 1 to 8 is implemented.

10. A readable storage medium, characterized in that: The readable storage medium stores a computer program, and when the computer program is executed by the processor, the power battery parking heating and stall protection method according to any one of claims 1 to 8 is implemented.

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