Motor power limiting method and device, equipment and storage medium

Abstract

The invention relates to a motor power limiting method and device, equipment and a storage medium. The method comprises the steps that a motor index value of a current vehicle is acquired; determining the current fault level of the motor according to the motor index value; under the condition that the current fault level is a target fault level, determining a first limit value of the input power of the motor according to the current fault level; and adjusting the output power of a battery according to the first limit value so as to limit the input power of the motor based on the first limit value. According to the method, the current fault level of the motor can be detected, and the input power of the motor is adjusted when the current fault level is the target fault level, so that accidents caused by overlarge output power of the motor are avoided, and the personal safety of a user is protected.

Description

Technical Field

[0001] This application relates to the field of computer technology, and in particular, to a method, device, equipment, and storage medium for limiting the power of an electric motor. Background Art

[0002] With the development of technology, electric vehicles have become increasingly important in the transportation field due to their environmental protection and high efficiency advantages, and have become the first choice for many consumers' daily travel. However, just like traditional fuel vehicles may encounter engine failures, electric vehicles also face the potential risk of electric motor failures. Once the electric motor suddenly fails, if the handling is slightly off, it is very easy to cause a fire, and in more serious cases, it will lead to a series of chain accidents, posing a huge threat to the life and property safety of users. Therefore, how to scientifically and effectively control the electric motor has become a key problem that needs to be solved urgently. Summary of the Invention

[0003] This application provides a method, device, equipment, and storage medium for limiting the power of an electric motor. The method can detect the current fault level of the electric motor, and when the current fault level is the target fault level, adjust the input power of the electric motor to avoid accidents caused by excessive output power of the electric motor, protecting the personal safety of users.

[0004] In a first aspect, this application provides a method for limiting the power of an electric motor, the method comprising:

[0005] Obtain the motor index value of the current vehicle;

[0006] Determine the current fault level of the electric motor according to the motor index value;

[0007] When the current fault level is the target fault level, determine a first limit value of the input power of the electric motor according to the current fault level;

[0008] Adjust the output power of the battery according to the first limit value to limit the input power of the electric motor based on the first limit value.

[0009] Optionally, the determining the current fault level of the electric motor according to the motor index value includes:

[0010] Determine the fault score corresponding to each motor index value;

[0011] Determine the target score according to the fault score corresponding to each motor index value and the weight;

[0012] Determine the current fault level of the electric motor according to the target score.

[0013] Optionally, determining the first limit value of the motor input power according to the current fault level includes:

[0014] Determining a second limit value of the motor output power according to the current fault level and a first corresponding relationship, where the first corresponding relationship is used to indicate the mapping relationship between the fault level and the output power limit value;

[0015] Determining a first reference value of the motor input power according to the second limit value and a preset loss power;

[0016] Determining the first limit value of the motor input power according to the first reference value.

[0017] Optionally, determining the first limit value of the motor input power according to the first reference value includes:

[0018] Determining a target operating parameter according to the current fault level and a second corresponding relationship, where the second corresponding relationship is the mapping relationship between the fault level and the optimal operating parameter;

[0019] Determining a second reference value of the motor input power according to the target operating parameter;

[0020] Determining the first limit value of the motor input power according to the first reference value and the second reference value.

[0021] Optionally, adjusting the output power of the battery according to the first limit value includes:

[0022] Determining a third limit value according to the first limit value and the fixed power required by other devices, where the third limit value is the limit value of the battery output power;

[0023] Adjusting the output power of the battery according to the third limit value.

[0024] Optionally, adjusting the output power of the battery according to the third limit value includes:

[0025] Determining the difference between the battery output peak and the third limit value;

[0026] Determining the target attenuation duration required by the battery according to the difference;

[0027] Adjusting the attenuation duration of the battery according to the target attenuation duration, so that the battery adjusts the output power of the battery to the third limit value according to the target attenuation duration.

[0028] Optionally, the method further includes:

[0029] Determine the torque limit value at the first limit value according to the first limit value;

[0030] Determine the limit speed according to the torque limit value;

[0031] Adjust the driving state of the current vehicle according to the torque limit value and the limit speed.

[0032] In a second aspect, the present application provides a motor power limiting device, the device includes:

[0033] An acquisition unit for acquiring the motor index value of the current vehicle;

[0034] A first determination unit for determining the current fault level of the motor according to the motor index value;

[0035] A second determination unit for determining a first limit value of the motor input power according to the current fault level when the current fault level is the target fault level;

[0036] An adjustment unit for adjusting the output power of the battery according to the first limit value to limit the input power of the motor based on the first limit value.

[0037] Optionally, the first determination unit is used for:

[0038] Determine the fault score corresponding to each motor index value;

[0039] Determine the target score according to the fault score corresponding to each motor index value and the weight;

[0040] Determine the current fault level of the motor according to the target score.

[0041] Optionally, the second determination unit is used for:

[0042] Determine a second limit value of the motor output power according to the current fault level and a first corresponding relationship, where the first corresponding relationship is used to indicate the mapping relationship between the fault level and the output power limit value;

[0043] Determine a first reference value of the motor input power according to the second limit value and the preset loss power;

[0044] Determine the first limit value of the motor input power according to the first reference value.

[0045] Optionally, the second determination unit is used for:

[0046] Determine a target operating parameter according to the current fault level and a second corresponding relationship, where the second corresponding relationship is a mapping relationship between a fault level and an optimal operating parameter;

[0047] Determine a second reference value of the motor input power according to the target operating parameter;

[0048] Determine a first limit value of the motor input power according to the first reference value and the second reference value.

[0049] Optionally, the adjustment unit is configured to:

[0050] Determine a third limit value according to the first limit value and a fixed power required to be consumed by other devices, where the third limit value is a limit value of the battery output power;

[0051] Adjust the output power of the battery according to the third limit value.

[0052] Optionally, the adjustment unit is configured to:

[0053] Determine a difference between the battery output peak value and the third limit value;

[0054] Determine a target attenuation duration required for the battery according to the difference;

[0055] Adjust the attenuation duration of the battery according to the target attenuation duration, so that the battery adjusts the output power of the battery to the third limit value according to the target attenuation duration.

[0056] Optionally, the device further includes a third determination unit, and the third determination unit is configured to:

[0057] Determine a torque limit value at the first limit value according to the first limit value;

[0058] Determine a limit speed according to the torque limit value;

[0059] Adjust the driving state of the current vehicle according to the torque limit value and the limit speed.

[0060] In a third aspect, the present application provides a motor power limiting device, including: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor connected to the at least one bus; and at least one memory connected to the at least one bus, where the processor is configured to:

[0061] Obtain a motor index value of the current vehicle;

[0062] Determine the current fault level of the motor according to the motor index value;

[0063] When the current fault level is the target fault level, determine a first limit value of the motor input power according to the current fault level;

[0064] Adjust the output power of the battery according to the first limit value to limit the input power of the motor based on the first limit value.

[0065] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the above-mentioned motor power limiting method is implemented.

[0066] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art: obtaining the motor index value of the current vehicle; determining the current fault level of the motor according to the motor index value; when the current fault level is the target fault level, determining a first limit value of the motor input power according to the current fault level; adjusting the output power of the battery according to the first limit value to limit the input power of the motor based on the first limit value. It can be seen that the present application can detect the current fault level of the motor, and when the current fault level is the target fault level, adjust the input power of the motor to avoid accidents caused by excessive output power of the motor and protect the personal safety of users. Description of the Drawings

[0067] The drawings here are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0068] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0069] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated, and the drawings in the drawings do not constitute a proportional limitation.

[0070] Figure 1 It is a schematic flow chart of a motor power limiting method provided by an embodiment of the present application;

[0071] Figure 2 It is a schematic flow chart of a method for determining the current fault level provided by an embodiment of the present application;

[0072] Figure 3Flow chart of a method for determining a first limit value provided by an embodiment of the present application;

[0073] Figure 4 Flow chart of another method for determining a first limit value provided by an embodiment of the present application;

[0074] Figure 5 Flow chart of a method for adjusting the output power of a battery provided by an embodiment of the present application;

[0075] Figure 6 Curve graph of another power attenuation provided by an embodiment of the present application;

[0076] Figure 7 Flow chart of another method for adjusting the power of a battery provided by an embodiment of the present application;

[0077] Figure 8 Flow chart of another method for adjusting the driving state provided by an embodiment of the present application;

[0078] Figure 9 Flow chart of a motor power limiting device provided by an embodiment of the present application;

[0079] Figure 10 Schematic diagram of a motor power limiting device provided by an embodiment of the present application. Detailed implementation

[0080] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0081] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0082] With the development of technology, electric vehicles have become increasingly important in the transportation field due to their environmental protection, high efficiency and other advantages, and have already become the first choice for many consumers' daily travel. However, just like traditional fuel vehicles may encounter engine failures, electric vehicles also face the potential risk of motor failures. Once the motor suddenly fails, if the handling is slightly off, it is extremely easy to cause a fire, and in more serious cases, it will lead to a series of chain accidents, posing a huge threat to the life and property safety of users. Therefore, how to scientifically and effectively control the motor has become a key problem that needs to be solved urgently at present.

[0083] To solve the above problems, during the vehicle driving process, the vehicle control system periodically collects the current value, voltage value and rotation speed value of the motor, and based on the current value, voltage value and rotation speed value, detects the fault level where the motor is located. When the fault level is the target fault level, according to the target fault level, determines the output power limit value of the motor, and then adjusts the output power of the battery according to this limit value, so that the battery restricts the input power of the motor based on the adjusted output power.

[0084] In summary, the embodiment of the present application provides a method for adjusting the motor power. This method can detect the current fault level of the motor, and when the current fault level is the target fault level, adjusts the input power of the motor to avoid accidents caused by excessive output power of the motor, protecting the personal safety of users. As Figure 1 shown, the specific steps include:

[0085] Step 101, obtain the motor index value of the current vehicle.

[0086] Among them, the motor index value is an index value that can determine the operating state of the motor. For example, the current value, voltage value and rotation speed value.

[0087] In this step, when the vehicle is in a driving state, the vehicle control system can periodically obtain the motor index value of the current vehicle, and perform subsequent steps based on the obtained motor index value.

[0088] Step 102, determine the current fault level of the motor according to the motor index value.

[0089] Among them, the fault level is used to indicate the severity of the motor fault. The motor fault degrees corresponding to different fault levels are different. In practice, different fault levels are divided according to different motor fault degrees. The higher the motor fault level, the more serious the corresponding motor fault degree, and the lower the motor fault level, the lighter the corresponding motor fault degree.

[0090] In this step, the vehicle control system pre-stores preset conditions corresponding to each fault level. When the motor index values obtained in step 101 meet the preset conditions corresponding to a certain fault level, that fault level is determined as the current fault level. For example, the preset conditions corresponding to fault level 0 are that the voltage, current, and rotational speed are all within the normal range.

[0091] In addition, this step can also consider the voltage, current, and rotational speed to determine the current fault level of the motor. The specific steps are as follows: According to the motor index values, determine the target index value; determine the target index range where the target index value is located, and based on the target index range and the pre-set corresponding relationship between the index range and the fault level, determine the current fault level of the motor.

[0092] Among them, the corresponding relationship between the index range and the fault level is set according to the actual experience of technicians. For example, in practice, through testing multiple actual vehicles, according to factors such as the impact of the fault on vehicle performance and the difficulty of maintenance, and in accordance with the fault levels of these actual vehicles, they are divided into multiple fault levels. The fault levels here cover different degrees from minor faults to serious faults. Then, for each fault level, according to the actual vehicles corresponding to that fault level, calculate the target index values corresponding to these actual vehicles respectively. When determining the index range, based on the maximum and minimum values among these target index values, they can be directly used as the upper and lower limits of the index range of that fault level, or according to the actual situation, appropriately increase a certain value on the basis of the maximum value and appropriately decrease a certain value on the basis of the minimum value, so as to obtain a reasonable index range corresponding to that fault level. Through the above method, the corresponding relationship between the index range and the fault level is obtained and stored in the vehicle control system. To make the above corresponding relationship more accurate, sufficient data support is required, which requires that the actual vehicles corresponding to each fault level should include various types of vehicles to ensure that all possible situations are covered.

[0093] In the above process, the specific process of determining the target index value according to the motor index values is as follows: Obtain the voltage weight corresponding to the voltage, the current weight corresponding to the current, and the rotational speed weight corresponding to the rotational speed. Multiply the voltage weight by the voltage to obtain the first value, multiply the current weight by the current to obtain the second value, multiply the rotational speed weight by the rotational speed to obtain the third value, and then add the first value, the second value, and the third value to obtain the target index value.

[0094] Among them, the weight represents the influence degree of the corresponding motor index value on the motor fault. These weights are tested on multiple actual vehicles, and data fitting is carried out using big data to obtain the mapping relationship between the motor fault level and voltage, current, and speed. The weights corresponding to voltage, current, and speed are calculated through factor analysis, and are calculated using the variance interpretation rate after rotation according to the information concentration size, and finally normalized. Generally speaking, the voltage weight is the largest, the current weight is the second, and the speed weight is the smallest.

[0095] Of course, the present application can also determine the current fault level by determining the fault score corresponding to each motor index value, and other methods can also be used to determine the current fault level, which is not limited here.

[0096] Step 103, when the current fault level is the target fault level, determine the first limit value of the motor input power according to the current fault level.

[0097] Among them, when the current vehicle is at the target fault level, the motor has a fault but its performance has declined. At this time, if the normal input power is still used to drive the motor, it is very likely to cause sudden accidents such as motor explosion. Therefore, to avoid such sudden accidents, the motor input power can be reduced in this case. When the vehicle is not at the target fault level, there are the following situations: one is that the motor has no faults and is in good operating condition; the second is that the motor has some minor faults, such as mild wear of components, etc., but these faults do not affect the motor performance and the motor can still work normally; the third is that the motor has serious faults, such as serious burning of the motor winding, etc., resulting in the motor being unable to drive the vehicle normally. Therefore, the target fault level is the fault level indicating that the motor has a fault and its performance has declined, that is, the decline range of the motor performance is greater than 0 (indicating a decline in performance, different from the fault-free state) and less than 100% (indicating that the motor still has a certain working ability and has not completely lost its function). Different target fault levels correspond to different performance decline ranges, and the specific decline range can be determined according to the changes in various performance indicators of the motor. For example, it can be determined by detecting the speed, voltage, and current of the motor. For example, obtain the actual speed of the motor when it is running at the rated voltage and rated load, and compare the actual speed with the rated speed of the motor to obtain the decline range of the motor performance. Specifically, for a motor with a rated speed of 1500 revolutions per minute, the actual measured speed is 1400 revolutions per minute, then the speed decline range is (1500 - 1400) ÷ 1500 × 100% ≈ 6.7%. It can also be determined by the deviation degree of various performance indicators of the motor, which is not limited here.

[0098] For example, this step provides multiple fault levels, fault descriptions corresponding to different fault levels, and corresponding fault handling measures. Specifically, as shown in Table 1. Among these fault levels, when the fault level is 0 and 1, since there is no fault or the fault is minor, the vehicle does not need to be processed. When the fault level is 4 or 5, since the component prohibits power output, it indicates that the fault is relatively serious and the operation of the motor cannot be adjusted by restricting power. For faults in motors involved in levels 2 and 3 with a performance decline, levels 2 and 3 can be set as the target fault levels, and other levels can be set as non-target fault levels. Among them, when the target fault level is level 2, the motor performance declines slightly, and when the target fault level is level 3, the motor performance declines significantly.

[0099] Table 1

[0100]

[0101] In the above process, the first limit value is the limit value of the motor input power. This limit value is negatively correlated with the degree of motor performance decline. The smaller the performance decline, the larger the limit value; conversely, the larger the performance decline, the smaller the limit value. The degrees of performance decline corresponding to different target fault levels are different. To more clearly define the degree of performance decline, corresponding standards can be set, such as dividing levels according to the deviation degree of various motor performance indicators (such as speed, torque, efficiency, etc.). For example, when the target fault level is fault level 2, the motor performance corresponding to fault level 2 declines slightly (such as the performance indicators deviate from the normal range by 10%-20%), and the corresponding output power limit value can be set to 75% of the maximum output power of the motor. When the target fault level is fault level 3, the motor performance corresponding to fault level 3 declines significantly (such as the performance indicators deviate from the normal range by more than 30%), and the corresponding output power limit value can be set to 50% of the maximum output power of the motor. When more fault levels are set in practice, based on the rule that "the limit value is negatively correlated with the degree of motor performance decline, and the degree of performance decline is divided according to the deviation degree of performance indicators", the performance corresponding to each fault level can be analyzed to obtain the degree of performance decline corresponding to each fault level. Then, according to the degree of performance decline corresponding to each fault level, the corresponding output power limit value is set for each fault level, and thus the corresponding relationship between the fault level and the output power limit value is obtained.

[0102] In this step, the vehicle control system stores the corresponding relationship between the fault level and the output power limit value. When the current fault level is the target fault level, the first limit value of the motor input power is determined according to the current fault level and this corresponding relationship.

[0103] Step 104: Adjust the output power of the battery according to the first limit value to limit the input power of the motor based on the first limit value.

[0104] Among them, the limit result is that the input power of the motor is less than or equal to the first limit value. When there is almost no loss between the battery and the motor, the input power of the motor is equal to the first limit value. When there is loss during the transmission between the battery and the motor, the input power of the motor is less than the first limit value.

[0105] In this step, the execution entities of steps 101 to 103 are specifically the motor controller in the vehicle control system, and the execution entity of this step is specifically the battery management system in the vehicle control system. In this way, after the motor controller determines the first limit value, it sends it to the battery management system. When the battery only supplies power to the motor, the output power of the battery is the input power of the motor. Therefore, only by controlling the battery management system to set the total output power of the battery to the first limit value can the input power of the motor be set to the first limit value. When the battery supplies power to other devices on the vehicle (such as air conditioners, stereos, etc.) in addition to the motor, before setting the battery output power, the vehicle control system needs to first determine the total power of these other devices and send the total power value to the battery management system. After receiving the information, the battery management system adds the first limit value to the total power of other devices to determine the total power that the battery needs to output. Then, the battery management system adjusts the actual output power of the battery according to the calculated total power, so that the battery can provide the input power that meets the first limit value to the motor based on the adjusted output power, and at the same time provide the required power for other devices.

[0106] Among them, the battery management system is mainly responsible for managing the battery. For example, managing the output power of the battery.

[0107] In the embodiment of the present application, obtain the motor index value of the current vehicle; determine the current fault level of the motor according to the motor index value; in the case where the current fault level is the target fault level, determine the first limit value of the motor input power according to the current fault level; adjust the output power of the battery according to the first limit value to limit the input power of the motor based on the first limit value. It can be seen that the present application can detect the current fault level of the motor and adjust the input power of the motor when the current fault level is the target fault level, so as to avoid accidents caused by excessive output power of the motor and protect the personal safety of users.

[0108] In the embodiments of the present application, the vehicle control system can also determine the fault score corresponding to each motor index value, and then determine the target score based on these fault scores, so as to determine the current fault level of the motor according to the target score. Therefore, the embodiments of the present application provide a method for determining the current fault level, and the specific steps include:

[0109] Step 201, determine the fault score corresponding to each motor index value.

[0110] Among them, the fault score represents the possibility of a fault. It is determined according to the degree to which the motor index value deviates from the normal index range. When the motor index value deviates more from the normal index range, the corresponding fault score is higher, and the represented fault degree is more serious. On the contrary, the corresponding fault score is lower, and the represented fault degree is lighter.

[0111] In this step, when the collected voltage is within the first voltage range, it is determined that the motor is normal in terms of voltage. At this time, its fault score is set to the first voltage score. When the collected voltage is within the second voltage range and the duration does not exceed the preset time, its fault score is set to the second voltage score. When the collected voltage is within the second voltage range and the duration exceeds the preset time, the motor performance drops slightly and overvoltage or undervoltage occurs, which is judged as a minor fault, and its fault score is set to the third voltage score. When the collected voltage is within the third voltage range and the duration does not exceed the preset time, its fault score is set to the fourth voltage score. When the collected voltage is within the third voltage range and the duration exceeds the preset time, the motor performance drops significantly, which is judged as a serious fault, and its corresponding fault score is set to the fifth voltage score.

[0112] Among them, the endpoint values of the first voltage range are ±10% of the rated voltage, which is the normal voltage range. The second voltage range includes two ranges. One range has endpoint values of 10% and 20% of the rated voltage respectively, and the other range has endpoint values of -10% and -20% of the rated voltage respectively. The second voltage range includes two ranges. One range has endpoint values of 20% and positive infinity of the rated voltage respectively, and the other range has endpoint values of -20% and negative infinity of the rated voltage respectively. The first voltage score, the second voltage score, the third voltage score, the fourth voltage score, and the fifth voltage score increase in sequence. For example, the first voltage score is 0, the second voltage score is 30, the third voltage score is 60, the second voltage score is 80, and the fifth voltage score is 100.

[0113] Current is the electrical energy consumed by the motor during operation, which directly affects the working efficiency and heat generation of the motor. When the collected current is within the first current range, it is determined that the motor is normal in terms of current. At this time, its fault score is set to the first current score. When the collected current is within the second current range, the motor performance decreases slightly and there is an overload situation, which is judged as a minor fault, and its fault score is set to the second current score. When the collected current is within the third current range, the motor performance decreases significantly, which is judged as a serious fault, and its corresponding fault score is set to the third current score.

[0114] Among them, the endpoint values of the first current range are 0.8 times and 1.1 times the rated current, which is the normal current range. The endpoint values of the second current range are 0.4 times and 1.5 times the rated current. The endpoint values of the second current range are 1.5 times and positive infinity of the rated current. The first current score, the second current score, and the third current score increase in sequence. For example, the first current score is 0, the second current score is 60, and the third current score is 100.

[0115] In practice, the rotational speed directly affects the output power and working efficiency of the motor. When the collected voltage is within the first rotational speed range, it is determined that the motor is normal in terms of rotational speed. At this time, its fault score is set to the first rotational speed score. When the collected voltage is within the second rotational speed range, it is determined that the motor is abnormal in terms of rotational speed. At this time, its fault score is set to the second rotational speed score. When the collected voltage is within the third rotational speed range, it is determined that the motor has a serious fault in terms of rotational speed. At this time, its fault score is set to the third rotational speed score.

[0116] Among them, the endpoint values of the first rotational speed range are 0 and 1% of the rated rotational speed, which is the normal rotational speed range. The endpoint values of the second rotational speed range are 1% and 5% of the rated rotational speed. The endpoint values of the third rotational speed range are 5% and positive infinity of the rated rotational speed. The first rotational speed score, the second rotational speed score, and the third rotational speed score increase in sequence. For example, the first rotational speed score is 0, the second rotational speed score is 60, and the third rotational speed score is 100.

[0117] Step 202: Determine the target score according to the fault score corresponding to each motor index value and the weight.

[0118] Among them, the weight represents the degree of influence on the motor performance. The voltage has the greatest influence on the motor performance, followed by the current, and finally the rotational speed.

[0119] In this step, for each motor index value, multiply the corresponding fault score by the weight to obtain the product corresponding to this motor index value, and add up the products corresponding to each motor index value to obtain the target score.

[0120] Step 203: Determine the current fault level of the motor according to the target score.

[0121] In this step, the vehicle control system stores multiple score ranges and the corresponding relationship between the score ranges and the fault levels. Then, according to the target score, the score range where it is located is determined, and this score range is determined as the target score range. Then, according to the target score range and the pre-stored corresponding relationship between the score range and the fault level, the fault level corresponding to the target score range is determined, and this fault level is the current fault level of the motor.

[0122] Further, the method for determining the corresponding relationship between the score range and the fault level is as follows: Collect a large amount of data related to vehicle faults, including all possible motor indicators under each fault level. Then, for each fault level, according to the motor indicators and the score calculation method under this fault level, multiple scores are calculated. According to the maximum and minimum values of these scores, the score range corresponding to this fault level is determined. According to the above method, the corresponding relationship between the fault level and the score range is obtained. Among them, the calculation method is the same as the calculation of the above target score.

[0123] In the embodiment of the present application, the vehicle control system can also determine the output power limit value of the motor according to the current fault level. Then, according to the output power limit value, the input power limit value is determined, and thus the first limit value of the motor is obtained. Therefore, the embodiment of the present application provides a method for determining the first limit value, and this method is as Figure 3 shown, and the specific steps include:

[0124] Step 301, determine the second limit value of the motor output power according to the current fault level and the first corresponding relationship.

[0125] Among them, the second limit value is the limit value of the motor output power. The motor output power refers to the mechanical power output on the motor shaft, that is, after the motor converts electrical energy into mechanical energy, the power that can do work externally. The first correspondence is used to indicate the mapping relationship between the fault level and the output power limit value. In practice, the motor fault levels and motor performances corresponding to different fault levels are different. As shown in Table 1, there is no fault in the motor corresponding to the fault level 0, there is a minor fault in the motor corresponding to the fault level 1, but the motor performance remains unchanged, and there is a fault in the motor corresponding to the fault level 2, but the motor performance decreases. And the output powers corresponding to different motor performances are different. In this step, when the motor performance is lower, its corresponding output power is lower, and when the motor performance is higher, its corresponding output power is higher. As shown in Table 1, when the fault level is 0, the motor performance is the best and its corresponding output power is the highest. When the fault level is 2, the motor performance decreases, and its corresponding output power also decreases. When the fault level is 3, the motor performance drops significantly, and its corresponding output power also drops significantly. According to the above rules, for each fault level, its performance indicators such as current, voltage, speed and other related data can be comprehensively analyzed to obtain the corresponding motor output power limit value. For example, the actual power can be calculated according to the current and voltage in combination with the power calculation formula of the motor, and the relationship between the motor performance and the output power can be evaluated in combination with factors such as speed. Then, according to the motor output power limit value corresponding to each fault level, the mapping relationship between the fault level and the motor output power limit value is created.

[0126] In this step, the vehicle control system can obtain the pre-stored correspondence between the fault level and the output power limit value, and determine the output power limit value according to the target fault level and this correspondence, and determine it as the second limit value of the motor.

[0127] For example, the output power limit value corresponding to the fault level 2 is 75% of the maximum output power of the motor. The output power limit value corresponding to the fault level 3 is 50% of the maximum output power of the motor. When the target fault level is the fault level 2, 75% of the maximum output power of the motor is determined as the second limit value, and when the target fault level is the fault level 3, 50% of the maximum output power of the motor is determined as the second limit value.

[0128] Step 302, determine the first reference value of the motor input power according to the second limit value and the preset loss power.

[0129] Among them, the loss power is the power lost when the electrical power is converted into mechanical power. The first reference value is the reference limit value of the motor input power. The motor input power refers to the electrical power obtained by the motor from the power source, that is, the total power consumed by the motor during operation.

[0130] In this step, the technician can determine the loss power based on the input power and output power of the motor and store it in the vehicle control system. When this step needs to be executed, the vehicle control system can obtain the pre-stored loss power, add the second limit value and the loss power to obtain the first reference value of the motor.

[0131] In addition, the longer the vehicle is used, the greater its corresponding loss degree and the greater the loss power. Therefore, in practice, vehicles with different usage times are detected to obtain their corresponding loss powers, and then the corresponding relationship between the usage time and the loss power is established and stored in the vehicle control system. When it is necessary to determine the loss power of the current vehicle, the corresponding relationship between the pre-stored usage time and the loss power is obtained, and then the loss power to be used is determined according to the usage time of the current vehicle and this corresponding relationship.

[0132] In practice, the power of the motor operating under normal conditions is collected as the preset value, and the motor powers corresponding to different usage times without faults are tested. The motor powers corresponding to different usage times are subtracted from the preset value to obtain the loss powers corresponding to different usage times.

[0133] Step 303, determine the first limit value of the motor input power according to the first reference value.

[0134] In this step, the vehicle control system can directly determine the first reference value as the first limit value of the motor, or can determine other limit values based on other methods. For example, the first limit value is determined according to the first reference value and other reference values, which is not limited here.

[0135] In the embodiment of the present application, the vehicle control system can also determine the motor output power limit value in other ways, and then select the minimum value from this limit value and Figure 3 the limit value determined in the above embodiment and determine it as the first limit value of the motor. Therefore, the embodiment of the present application also provides a method for determining the first limit value, and this method is as Figure 4 shown, and the specific steps include:

[0136] Step 401, determine the target operating parameter according to the current fault level and the second corresponding relationship.

[0137] Among them, the second corresponding relationship is the mapping relationship between the fault level and the optimal operating parameter. The operating index is an index that can calculate the motor output power, including indexes such as the torque, speed, voltage, current, power factor, and efficiency of the motor.

[0138] In this step, optimization can be carried out with the motor output power as the target, and the corresponding relationship between the fault level and the optimal operation index can be obtained through the genetic algorithm. Specifically, operation indexes such as the motor fault level, battery power, motor speed, and vehicle speed are used as design variables, and the maintenance range of the power battery SOC and the 0-100 km / h acceleration time are used as constraints, with the constraint that the SOC (State of Charge) maintenance range is not less than 25% and the 0-100 km / h acceleration time does not exceed 15 s. With the motor output power as the optimization target, the optimal operation indexes of the motor under different motor fault levels are determined. The established mathematical model for the optimal design of the motor output power is as follows:

[0139] Objective function: Minf(X),

[0140] Decision variable: X = (x1, x2, x3, x4..),

[0141] Constraint conditions: Bsoc - 25 ≥ 0, tacc - 15 ≥ 0, xil < xi < xiU, i = 1, 2, 3, 4

[0142] In the formula, X is the design variable; f is the motor power obtained from the simulation calculation under different design variables X. Bsoc and tacc are the SOC value of the power motor and the 0-100 km / h acceleration time value respectively. The constraint is that Bsoc is not less than 25%, the constraint is that tacc does not exceed 15 s, and xil and xiU represent the upper and lower limits of different design variables.

[0143] The objective optimization genetic algorithm is used for objective optimization, with the number of iterations set to 100, the crossover rate set to 0.8, the mutation rate set to 0.05, and a total of 400 individuals are calculated. Finally, the optimal operation indexes of the motor are identified under different motor fault levels.

[0144] Step 402: Determine the second reference value of the motor input power according to the target operation parameters.

[0145] Among them, the second reference value is the reference limit value of the motor input power.

[0146] In this step, the second reference value of the motor can be calculated according to the target operation indexes. For example, when the motor is an AC motor, the target operation indexes are the target voltage, target current, and target power factor. According to these data and the preset formula, the second reference value is calculated. The preset formula is Among them, P in is the second reference value, U is the target voltage, I is the target current, and cosy is the target power factor.

[0147] The vehicle control system can also determine the motor output power according to the target operation indexes, and add this motor output power to the preset loss power to obtain the second reference value of the motor.

[0148] Further, when the target operating indicators are the target torque and the target speed, the output power of the motor is calculated according to the target torque, the target speed, and a preset formula. The above preset formula is Pout = T * n / 9550, where Pout is the output power of the motor, T is the target torque of the motor, and n is the target speed of the motor. When the motor is a DC motor, if the target operating indicators are the target voltage and the target current, the limit value of the output power of the motor can be calculated according to the target voltage and the target current. When the motor is an AC motor, if the target operating indicators are the target voltage, the target current, the target power factor, and the target motor efficiency, these data are multiplied to calculate the output power of the motor.

[0149] Step 403: Determine the first limit value of the input power of the motor according to the first reference value and the second reference value.

[0150] In this step, the vehicle control system can select the minimum limit value from the first reference value and the second reference value and determine it as the second reference value of the motor. Specifically, the first reference value and the second reference value are compared. When the first reference value is greater than or equal to the second reference value, the second reference value is determined as the first limit value of the motor. When the first reference value is less than the second reference value, the first reference value is determined as the first limit value of the motor.

[0151] In the embodiment of the present application, the vehicle control system can also obtain the fixed power required by other devices and send it to the battery management device. Then, the battery management device adds the first limit value and the fixed power to obtain the output power of the battery, and further adjusts the actual power of the battery according to the output power. Therefore, the embodiment of the present application provides a method for adjusting the output power of the battery. The method is as Figure 5 shown, and the specific steps include:

[0152] Step 501: Determine the third limit value according to the first limit value and the fixed power required by other devices.

[0153] Among them, the third limit value is the limit value of the output power of the battery. The fixed power is the power consumed by other devices of the current vehicle. Other devices are devices that need to be powered by the battery, such as air conditioners, stereos, and other devices.

[0154] In this step, the battery management device can add the first limit value and the fixed power to obtain the third limit value.

[0155] Step 502: Adjust the output power of the battery according to the third limit value.

[0156] In this step, the output power of the battery is adjusted to the third limit value so that the battery supplies power to the motor according to the first limit value.

[0157] In an embodiment of the present application, as Figure 6 shown, the horizontal axis is time t and the vertical axis is power p. When the actual operating power of the device reaches the maximum allowable transient power and the duration reaches the set maximum duration, the system will automatically start the regulation mechanism for the battery power, causing the battery power to start to slowly decay until it drops to the continuous power level. During this process, by flexibly adjusting the rate of power decay (i.e., the decay slope) and the time required for decay, the continuous power of the battery can be accurately regulated to meet the requirements for battery performance under different working conditions. Therefore, the embodiment of the present application provides a method for adjusting battery power, and this method is as Figure 7 shown, and the specific steps include:

[0158] Step 701, determine the difference between the battery output peak and the third limit value.

[0159] Among them, the battery output peak is the maximum allowable transient power, and the transient power refers to the power that the device can withstand or output in a short time.

[0160] In this step, subtract the third limit value from the battery output peak to obtain the difference between the battery output peak and the third limit value.

[0161] Step 702, determine the target decay duration required for the battery according to the difference.

[0162] In this step, the decay function is y = b - kt, where k and b are pre-set data amounts, and the corresponding change function Δy = k * Δt. In this way, the difference Δy can be substituted into the change function to obtain the target decay duration Δt.

[0163] Step 703, adjust the decay duration of the battery according to the target decay duration, so that the battery adjusts the output power to the third limit value according to the target decay duration.

[0164] In this step, the battery management system adjusts the decay duration of the battery to the target decay duration.

[0165] It should be noted that the target decay slope required for the battery can also be determined according to the difference, and the decay slope of the battery can be adjusted according to the target decay slope, so that the battery adjusts the output power to the third limit value according to the target decay slope.

[0166] In an embodiment of the present application, when the fault level reaches the target fault level, the vehicle can be automatically controlled to enter the limp home mode to limit the torque output and driving speed of the vehicle. Based on this, when restricting the motor power, the motor torque and the vehicle speed are synchronously restricted, so as to adjust the current driving state of the vehicle, ensure that the vehicle can still maintain the basic driving ability in the fault state, and ensure driving safety at the same time. Therefore, the embodiment of the present application provides a driving state adjustment method, and this method is as Figure 8 shown, and the specific steps include:

[0167] Step 801, determine the torque limit value under the first limit value according to the first limit value.

[0168] In this step, the corresponding relationship between the motor input power and the torque value can also be obtained, so that the torque limit value under the first limit value can be determined according to the first limit value and the corresponding relationship. Of course, other methods can also be used to determine the torque limit value, which is not limited here.

[0169] Step 802, determine the limit speed according to the torque limit value.

[0170] In this step, the preset output demand torque coefficient and the gear position signal value can also be obtained, and the torque limit value, the output demand torque coefficient and the gear position signal value are multiplied to obtain the limit speed.

[0171] Among them, the gear position signal value is a kind of signal data used in vehicle control systems such as automobiles to represent the current gear position state.

[0172] Step 803, adjust the driving state of the current vehicle according to the torque limit value and the limit speed.

[0173] In this step, the torsional limit value can also be adjusted according to conditions such as the gear position, the speed limit value, and the accelerator pedal to obtain the vehicle demand torque. Then, according to the vehicle demand torque and the limit speed, the torque and speed of the vehicle are adjusted to adjust the current driving state of the vehicle.

[0174] In addition, when the vehicle is in the motion state and the gear position is the forward gear or the reverse gear, the current motor allows the output power to be greater than 10 kw, and the whole vehicle is at the target fault level, the vehicle enters the limp home mode.

[0175] As Figure 9 shown, the embodiment of the present application provides a motor power limiting device, which corresponds to the method embodiment, and specifically includes:

[0176] An acquisition unit 901, configured to acquire the motor index value of the current vehicle;

[0177] The first determination unit 902 is configured to determine the current fault level of the motor according to the motor index value;

[0178] The second determination unit 903 is configured to determine a first limit value of the motor input power according to the current fault level when the current fault level is the target fault level;

[0179] The adjustment unit 904 is configured to adjust the output power of the battery according to the first limit value so as to limit the input power of the motor based on the first limit value.

[0180] Optionally, the first determination unit 902 is configured to:

[0181] Determine the fault score corresponding to each motor index value;

[0182] Determine the target score according to the fault score corresponding to each motor index value and the weight;

[0183] Determine the current fault level of the motor according to the target score.

[0184] Optionally, the second determination unit 903 is configured to:

[0185] Determine a second limit value of the motor output power according to the current fault level and a first correspondence relationship, where the first correspondence relationship is used to indicate the mapping relationship between the fault level and the output power limit value;

[0186] Determine a first reference value of the motor input power according to the second limit value and the preset loss power;

[0187] Determine the first limit value of the motor input power according to the first reference value.

[0188] Optionally, the second determination unit 903 is configured to:

[0189] Determine the target operating parameter according to the current fault level and a second correspondence relationship, where the second correspondence relationship is the mapping relationship between the fault level and the optimal operating parameter;

[0190] Determine a second reference value of the motor input power according to the target operating parameter;

[0191] Determine the first limit value of the motor input power according to the first reference value and the second reference value.

[0192] Optionally, the adjustment unit 904 is configured to:

[0193] Determine a third limit value according to the first limit value and the fixed power required to be consumed by other devices, where the third limit value is the limit value of the battery output power;

[0194] Adjust the output power of the battery according to the third limit value.

[0195] Optionally, the adjustment unit 904 is configured to:

[0196] Determine the difference between the battery output peak value and the third limit value;

[0197] Determine the target decay duration required for the battery according to the difference;

[0198] Adjust the decay duration of the battery according to the target decay duration, so that the battery adjusts the output power of the battery to the third limit value according to the target decay duration.

[0199] Optionally, the device further includes a third determination unit 905, and the third determination unit 905 is configured to:

[0200] Determine the torque limit value at the first limit value according to the first limit value;

[0201] Determine the limit speed according to the torque limit value;

[0202] Adjust the driving state of the current vehicle according to the torque limit value and the limit speed.

[0203] As Figure 10 shown, an embodiment of the present application provides a motor power limiting device, including a processor 1001, a communication interface 1002, a memory 1003, and a communication bus 1004. Among them, the processor 1001, the communication interface 1002, and the memory 1003 communicate with each other through the communication bus 1004.

[0204] The memory 1003 is used to store computer programs;

[0205] In an embodiment of the present application, when the processor 1001 is used to execute the program stored on the memory 1003, it implements the motor power limiting method provided by any one of the foregoing method embodiments, including:

[0206] Obtain the motor index value of the current vehicle;

[0207] Determine the current fault level of the motor according to the motor index value;

[0208] When the current fault level is the target fault level, determine the first limit value of the motor input power according to the current fault level;

[0209] Adjust the output power of the battery according to the first limit value to limit the input power of the motor based on the first limit value.

[0210] An embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps executed by the motor power limiting method provided in any of the foregoing method embodiments are implemented.

[0211] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0212] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the related technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0213] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" as used herein may also include the plural forms. The terms "include", "comprise", "contain", and "have" are inclusive and thus specify the presence of the stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be executed in the particular order described or illustrated, unless the execution order is explicitly stated. It should also be understood that additional or alternative steps can be used.

[0214] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A motor power limiting method, characterized in that: The method comprises: Get the motor index value of the current vehicle; Determining the current fault level of the motor according to the motor index value; In a case where the current fault level is a target fault level, determining a first limit value of the motor input power according to the current fault level; According to the first limit value, the output power of the battery is adjusted to limit the input power of the motor based on the first limit value.

2. The method according to claim 1, characterized in that: Determining the current fault level of the motor according to the motor index value includes: Determine the fault score corresponding to each motor index value; Determine the target score based on the fault score and weight corresponding to each motor index value; According to the target score, a current fault level of the motor is determined.

3. The method according to claim 1, characterized in that: The step of determining a first limit value of the motor input power according to the current fault level includes: Determine a second limit value of the motor output power according to the current fault level and a first corresponding relationship, wherein the first corresponding relationship is used to indicate a mapping relationship between the fault level and the output power limit value; Determining a first reference value of the motor input power according to the second limit value and a preset power loss; A first limit value of the motor input power is determined according to the first reference value.

4. The method according to claim 3, characterized in that: Determining a first limit value of the motor input power according to the first reference value includes: Determining target operating parameters according to the current fault level and a second corresponding relationship, wherein the second corresponding relationship is a mapping relationship between the fault level and the optimal operating parameter; Determining a second reference value of the motor input power according to the target operating parameter; A first limit value of the motor input power is determined according to the first reference value and the second reference value.

5. The method according to claim 1, characterized in that: The adjusting the output power of the battery according to the first limit value includes: Determine a third limit value according to the first limit value and the fixed power required to be consumed by other devices, where the third limit value is a limit value of the battery output power; The output power of the battery is adjusted according to the third limit value.

6. The method according to claim 5, characterized in that: The step of adjusting the output power of the battery according to the third limit value includes: determining a difference between a battery output peak value and the third limit value; Determine the target decay time required for the battery according to the difference; The decay time of the battery is adjusted according to the target decay time, so that the output power of the battery is adjusted to a third limit value according to the target decay time.

7. The method according to claim 1, characterized in that: The method further comprises: According to the first limit value, determining a torque limit value under the first limit value; Determining a speed limit according to the torque limit value; The current driving state of the vehicle is adjusted according to the torque limit value and the speed limit.

8. A motor power limiting device, characterized in that: The device comprises: An acquisition unit, used to acquire the motor index value of the current vehicle; A first determining unit, configured to determine a current fault level of the motor according to the motor index value; a second determining unit, configured to determine a first limit value of the motor input power according to the current fault level when the current fault level is a target fault level; An adjusting unit is used to adjust the output power of the battery according to the first limit value, so as to limit the input power of the motor based on the first limit value.

9. A motor power limiting device, characterized in that: include: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor connected to the at least one bus; at least one memory connected to the at least one bus, wherein the processor is configured to: Get the motor index value of the current vehicle; Determining the current fault level of the motor according to the motor index value; In a case where the current fault level is a target fault level, determining a first limit value of the motor input power according to the current fault level; According to the first limit value, the output power of the battery is adjusted to limit the input power of the motor based on the first limit value.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the motor power limiting method according to any one of claims 1 to 7 is implemented.

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