Motor control method and device, vehicle and medium

Abstract

The present application relates to the technical field of intelligent control, and discloses a motor control method, device, vehicle and medium, the present application determines the second temperature threshold based on the current motor temperature and the current motor temperature change rate, thereby considering the influence of the current motor temperature and the temperature rising speed by adopting the adaptive adjustment of the second temperature threshold, determining the derating coefficient by using the adaptive adjustment of the second temperature threshold, obtaining the first torque, and determining the second torque by considering the influence of the peak power, determining the actual torque limit value corresponding to the driving working condition and the power generation working condition of the motor by using the smaller value of the first torque and the second torque, the limitation of the actual torque limit value can prevent the permanent damage of the motor due to overheating, and can effectively alleviate the problem of the copper loss of the winding and the rapid increase of the temperature rise rate when the peak power is exceeded, the performance of the motor is ensured, the service life of the motor is improved, and the thermal protection effect is also achieved in the power generation working condition.

Description

Technical Field

[0001] This invention relates to the field of intelligent control technology, specifically to motor control methods, devices, vehicles, and media. Background Technology

[0002] Electric motors are the core components of new energy vehicles and play an important role in electric drive systems. As the performance requirements for electric motors become increasingly stringent, they face severe challenges. Prolonged operation under high loads can cause a sharp rise in motor temperature. When the motor temperature exceeds the critical temperature, it may lead to rotor demagnetization and burnout of the motor stator windings, which in turn can cause the electric drive force to fail. Summary of the Invention

[0003] In view of this, the present invention provides a motor control method, device, vehicle and medium to solve the problem in the related art that when the motor temperature exceeds the critical temperature, it may lead to rotor demagnetization and burnout of the motor stator winding, which in turn leads to failure of electric drive force.

[0004] In a first aspect, the present invention provides a motor control method, the method comprising:

[0005] Obtain the current motor temperature, current motor temperature change rate, current motor speed, and peak motor power;

[0006] When the current motor temperature is not less than the first temperature threshold, a second temperature threshold is determined based on the current motor temperature and the current motor temperature change rate, wherein the second temperature threshold is greater than the first temperature threshold;

[0007] When the current motor temperature is lower than the second temperature threshold, a derating factor is calculated based on the current motor temperature, the first temperature threshold, and the second temperature threshold.

[0008] The current external characteristic torque value is determined based on the current motor speed, and the first torque is calculated based on the product of the current external characteristic torque value and the derating factor.

[0009] The second torque is calculated based on the peak power, the current motor speed, and the derating factor.

[0010] Based on the smaller value between the first torque and the second torque, the actual torque limits corresponding to the driving and generating conditions are determined respectively, and the motor is operated and controlled according to the actual torque limits corresponding to the driving and generating conditions respectively.

[0011] This invention determines a second temperature threshold based on the current motor temperature and the rate of change of the current motor temperature. It then adopts an adaptive adjustment method for the second temperature threshold to account for the influence of the current motor temperature and the rate of temperature rise. By using the adaptively adjusted second temperature threshold to determine a derating factor, a first torque is obtained. The second torque is determined by considering the influence of peak power. The smaller of the first and second torques is used to determine the actual torque limit for the motor under driving and generating conditions, respectively. This actual torque limit prevents permanent damage to the motor due to overheating and effectively mitigates the problems of winding copper loss and rapid temperature rise when peak power is exceeded. This ensures motor performance while extending its service life and also provides thermal protection during generating conditions.

[0012] In one optional implementation, determining the second temperature threshold based on the current motor temperature and the current motor temperature change rate includes:

[0013] The temperature thresholds corresponding to the motor overheating fault under different motor temperatures and motor temperature change rates are calibrated to obtain the mapping relationship between different motor temperatures, motor temperature change rates and temperature thresholds.

[0014] Based on the mapping relationship, a second temperature threshold corresponding to the current motor temperature and the current motor temperature change rate is determined.

[0015] This invention calibrates the temperature threshold corresponding to the motor over-temperature fault under different motor temperatures and motor temperature change rates. This allows for an accurate mapping relationship between motor temperature, motor temperature change rate, and temperature threshold. Based on this mapping relationship, a second temperature threshold that conforms to the actual operating conditions of the motor and causes an over-temperature fault can be obtained. This provides an accurate data basis for temperature protection of the motor, further ensuring motor performance while improving the motor's service life.

[0016] In one optional implementation, the step of calculating the derating factor based on the current motor temperature, the first temperature threshold, and the second temperature threshold includes:

[0017] Calculate the first temperature difference between the current motor temperature and the first temperature threshold, and calculate the second temperature difference between the second temperature threshold and the first temperature threshold;

[0018] The derating factor is determined based on the ratio of the first temperature difference to the second temperature difference.

[0019] This invention utilizes the ratio of the temperature difference between the real-time motor temperature and a first temperature threshold to the temperature difference between a second temperature threshold and the first temperature threshold to obtain a derating coefficient. This enables linear adjustment of the subsequent actual torque limit, ensuring the stability of the actual torque adjustment of the motor. It avoids the problem of drastic fluctuations in motor output power and a significant increase in battery energy consumption caused by large adjustments to motor torque, thereby improving the vehicle's driving range. At the same time, excessive torque adjustment can make the vehicle overly responsive at low speeds, requiring more precise control from the driver and potentially leading to a sense of loss of control. Linear and stable adjustment of the actual torque limit of the motor can improve the driving experience for users during low-speed driving.

[0020] In one optional implementation, calculating the second torque based on the peak power, the current motor speed, and the derating factor includes:

[0021] Calculate the current peak torque based on the peak power and the current motor speed;

[0022] The second torque is calculated based on the product of the current peak torque and the derating factor.

[0023] This invention calculates the current peak torque corresponding to the current motor speed using the motor's peak power, and then obtains the torque limit corresponding to the peak power by multiplying the current peak torque by the derating factor. This ensures that the motor does not exceed its peak power, thereby avoiding problems such as winding copper loss and rapid temperature rise, and further improving the service life of the motor.

[0024] In one optional implementation, determining the actual torque limits corresponding to the driving and power generation conditions based on the smaller of the first torque and the second torque includes:

[0025] The smaller value between the first torque and the second torque is determined as the maximum actual torque limit under the driving condition;

[0026] The smaller of the first torque and the second torque is negativeized and determined as the minimum actual torque limit under the power generation condition.

[0027] This invention determines the smaller of the first torque and the second torque as the maximum actual torque limit under driving conditions. This ensures that the motor can avoid overheating and damage, and extend its service life, as long as the operating torque meets the actual torque limit, regardless of whether the motor is operating at high or low speed. Furthermore, by taking the negative of the smaller of the first torque and the second torque and determining it as the minimum actual torque limit under power generation conditions, the invention achieves thermal protection for the motor under power generation conditions.

[0028] In an optional implementation, the method further includes:

[0029] Determine whether the smaller of the first torque and the second torque is greater than the product of the current external characteristic torque value and a set limit coefficient, wherein the set limit coefficient is greater than 0 and less than or equal to 1;

[0030] When the smaller of the first torque and the second torque is greater than the product of the current external characteristic torque value and the set limit coefficient, the minimum actual torque limit corresponding to the power generation condition is updated to the negative of the product of the current external characteristic torque value and the set limit coefficient.

[0031] This invention further limits the minimum actual torque limit under power generation conditions by comparing the current external characteristic torque value of the motor with the product of a set limit coefficient, thereby preventing damage to the motor due to excessive operating torque and further extending the service life of the motor.

[0032] In an optional implementation, the method further includes:

[0033] When the current motor temperature is not less than the second temperature threshold, the motor is controlled to output zero torque in both driving and generating modes.

[0034] This invention achieves rapid motor cooling by directly controlling the motor to output zero torque under both driving and generating conditions when the current motor temperature is not lower than a second temperature threshold, thereby minimizing motor damage and extending motor lifespan.

[0035] In an optional implementation, the method further includes:

[0036] When the current motor temperature is less than the first temperature threshold, the maximum actual torque limit corresponding to the driving condition is determined to be the current external characteristic torque value, and the minimum actual torque limit corresponding to the power generation condition is determined to be the torque value after taking the negative of the current external characteristic torque value of the motor.

[0037] The motor is controlled to operate according to the maximum actual torque limit corresponding to the driving condition and the minimum actual torque limit corresponding to the power generation condition.

[0038] This invention improves the motor's torque capability and maximizes its performance by controlling the motor to operate at its current external characteristic torque value during driving and at the negative of its current external characteristic torque value during power generation when the current motor temperature is below a first temperature threshold, since the motor does not have an overheating problem.

[0039] In a second aspect, the present invention provides a motor control device, the device comprising:

[0040] The acquisition module is used to acquire the current motor temperature, current motor temperature change rate, current motor speed, and peak power of the motor.

[0041] A first processing module is configured to determine a second temperature threshold based on the current motor temperature and the current motor temperature change rate when the current motor temperature is not less than a first temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold.

[0042] The second processing module is used to calculate a derating factor based on the current motor temperature, the first temperature threshold and the second temperature threshold when the current motor temperature is less than the second temperature threshold.

[0043] The third processing module is used to determine the current external characteristic torque value based on the current motor speed, and to calculate the first torque based on the product of the current external characteristic torque value and the derating factor;

[0044] The fourth processing module is used to calculate the second torque based on the peak power, the current motor speed, and the derating factor;

[0045] The fifth processing module is used to determine the actual torque limit values ​​corresponding to the driving condition and the generating condition based on the smaller value of the first torque and the second torque, and to control the operation of the motor according to the actual torque limit values ​​corresponding to the driving condition and the generating condition.

[0046] Thirdly, the present invention provides a vehicle, the vehicle comprising: a controller, the controller comprising:

[0047] The memory and processor are interconnected and communicate with each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the method described in the first aspect and any of its alternative embodiments.

[0048] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions that cause a computer to perform the method provided in the first aspect or any corresponding embodiment thereof.

[0049] The beneficial effects of this invention are:

[0050] This invention determines a second temperature threshold based on the current motor temperature and the rate of change of the current motor temperature. It then adopts an adaptive adjustment method for the second temperature threshold to account for the influence of the current motor temperature and the rate of temperature rise. By using the adaptively adjusted second temperature threshold to determine a derating factor, a first torque is obtained. The second torque is determined by considering the influence of peak power. The smaller of the first and second torques is used to determine the actual torque limit for the motor under driving and generating conditions, respectively. This actual torque limit prevents permanent damage to the motor due to overheating and effectively mitigates the problems of winding copper loss and rapid temperature rise when peak power is exceeded. This ensures motor performance while extending its service life and also provides thermal protection during generating conditions. Attached Figure Description

[0051] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0052] Figure 1 This is a flowchart of a motor control method according to an embodiment of the present invention;

[0053] Figure 2 This is a flowchart of another motor control method according to an embodiment of the present invention;

[0054] Figure 3 This is a flowchart illustrating the specific process for determining the torque capability of a motor according to an embodiment of the present invention;

[0055] Figure 4 This is a schematic diagram showing the relationship between motor operating torque and temperature under driving and generating conditions.

[0056] Figure 5 This is a schematic diagram of the structure of a motor control device according to an embodiment of the present invention;

[0057] Figure 6 This is a schematic diagram of the structure of a vehicle controller according to an embodiment of the present invention. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] Electric motors are the core components of new energy vehicles and play an important role in electric drive systems. As the performance requirements for electric motors become increasingly stringent, they face severe challenges. Prolonged operation under high loads can cause a sharp rise in motor temperature. When the motor temperature exceeds the critical temperature, it may lead to rotor demagnetization and burnout of the motor stator windings, which in turn can cause the electric drive force to fail.

[0060] To address the aforementioned issues, the technical solution employed in related technologies involves setting two threshold temperatures based on the allowable temperature of the motor, pre-setting the relationship between the threshold temperatures and the motor torque output, and setting a hysteresis temperature. By using torque and temperature hysteresis settings, the motor is prevented from repeatedly starting to reduce torque or locking up due to temperature jumps at the threshold. This method effectively protects the motor from damage due to overheating and minimizes the poor driving experience caused by the motor stopping torque output due to overheating.

[0061] However, the above solution has the following problems:

[0062] 1. The above solution specifies that torque should be reduced when the temperature exceeds the first threshold but is below the second threshold. However, in actual operating conditions, the motor temperature rise curve exhibits diverse trends and heat accumulation occurs. The above solution only considers the impact of motor temperature on the motor system, without considering the impact of the rate of temperature rise on the motor system, and therefore cannot effectively protect the motor.

[0063] 2. The above solution only considers the thermal protection of the motor by temperature, without considering the impact of peak power on the motor system. When the motor operates above the peak power, it will cause a surge in winding copper loss and temperature rise rate, which will affect the service life of the motor.

[0064] 3. The above solution only considers protecting the motor from overheating during the driving operation (positive speed and positive torque), and does not protect the motor from overheating during the generating operation (positive speed and negative torque).

[0065] To address the aforementioned issues, this invention provides a motor control scheme. By acquiring the current motor temperature and calculating the temperature change rate in real time, a second temperature threshold is dynamically obtained using the temperature change rate. When the motor temperature exceeds a first temperature threshold but is less than the second temperature threshold, the maximum torque capability 1 is calculated based on the external characteristic torque, motor temperature, first temperature threshold, and second temperature threshold. The current motor speed and preset peak power are also acquired, and the torque limit value affected by the peak power under driving conditions, i.e., the maximum torque capability 2, is calculated. The smaller value between maximum torque capability 1 and maximum torque capability 2 is then determined as the maximum torque limit value under driving conditions, and simultaneously, the corresponding minimum torque limit value under power generation conditions is determined.

[0066] The motor control scheme provided in this invention can prevent permanent damage to the motor due to overheating, ensuring motor performance while extending its service life. The introduction of a minimum torque limit provides thermal protection even under power generation conditions. The use of a variable second temperature threshold considers the combined effects of motor temperature and its rate of rise. The adoption of peak power limiting effectively mitigates the problems of winding copper losses and a surge in temperature rise rate when exceeding peak power.

[0067] According to an embodiment of the present invention, a motor control method embodiment is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0068] This embodiment provides a motor control method that can be applied to vehicle controllers such as microcontrollers (MCUs) and other control chips. Figure 1 This is a flowchart of a motor control method according to an embodiment of the present invention, such as... Figure 1 As shown, the process includes the following steps:

[0069] Step S101: Obtain the current motor temperature, current motor temperature change rate, current motor speed, and peak power of the motor.

[0070] Specifically, the current motor temperature is obtained through temperature monitoring equipment, such as a temperature sensor mounted on the vehicle for motor temperature measurement. The rate of change of the current motor temperature can be obtained by subtracting the motor temperature collected at the current sampling moment from the motor temperature collected at the previous sampling moment, or by subtracting the motor temperature value read at the current moment from the motor temperature value read again after a fixed delay. This invention is not limited to these methods. The peak power of the motor is a fixed parameter of the motor and can be obtained from the motor's operation manual or product manual through the motor model.

[0071] Step S102: When the current motor temperature is not less than the first temperature threshold, determine the second temperature threshold based on the current motor temperature and the current motor temperature change rate.

[0072] The first temperature threshold is the critical temperature value at which the motor may have a potential overheating risk and requires temperature protection control. This critical temperature value can be selected through motor testing or based on human experience. When the motor temperature is below the first temperature threshold, the motor does not have an overheating problem. The second temperature threshold is greater than the first temperature threshold. The second temperature threshold is the critical temperature value that characterizes the motor's overheating damage. When the motor temperature exceeds this critical temperature value, it indicates that the motor has begun to experience overheating damage. The second temperature threshold is closely related to the motor's actual temperature and the rate of temperature change. Under the same operating temperature conditions, the faster the motor's temperature rises, the more likely it is to overheat and damage, and the smaller the second temperature threshold will be. Similarly, under the same temperature rise rate, the higher the motor's actual temperature, the more likely it is to overheat and damage, and the smaller the second temperature threshold will be.

[0073] Step S103: When the current motor temperature is less than the second temperature threshold, calculate the derating factor based on the current motor temperature, the first temperature threshold, and the second temperature threshold.

[0074] Specifically, as the above analysis shows, when the motor is running in the temperature range between the first temperature threshold and the second temperature threshold, in order to avoid overheating and damage to the motor, it is necessary to limit the torque of the motor. Specifically, the derating factor can be calculated by using the current motor temperature and the first and second temperature thresholds. This derating factor is used to characterize the degree of limitation on the motor's operating torque. The value of the derating factor is between 0 and 1. When the derating factor is 1, it indicates that no torque limitation is required. When the derating factor is 0, it indicates that the motor output torque is zero. For example, when the derating factor is 0.5, it indicates that the motor output torque is limited by 50%.

[0075] Step S104: Determine the current external characteristic torque value based on the current motor speed, and calculate the first torque based on the product of the current external characteristic torque value and the derating factor.

[0076] Specifically, since there is a relationship between motor speed and torque through the motor's external characteristic curve, which is common knowledge to those skilled in the art, the current external characteristic torque value can be obtained from the motor's external characteristic curve by using the motor's current speed. By using the motor's external characteristic curve to select the current external characteristic torque value as the torque limiting reference, the motor can be ensured to operate within a safe range and its output capacity maximized.

[0077] Step S105: Calculate the second torque based on the peak power, the current motor speed, and the derating factor.

[0078] Specifically, the peak power is the maximum operating power to avoid problems such as winding copper loss and rapid temperature rise rate of the motor. By using the peak power and the actual speed of the motor, another torque limit benchmark value can be calculated according to the correspondence between power, speed and torque. Then, it is further limited by the derating factor to obtain the second torque, which provides accurate data reference for determining the actual torque limit of the motor.

[0079] Step S106: Based on the smaller value of the first torque and the second torque, determine the actual torque limit values ​​corresponding to the driving condition and the generating condition, respectively, and control the operation of the motor according to the actual torque limit values ​​corresponding to the driving condition and the generating condition, respectively.

[0080] Specifically, in order to ensure the safe operation of the motor under different operating conditions and avoid damage due to overheating, the actual torque limit of the motor under different operating conditions is set based on the smaller value of the first torque and the second torque, and the motor is controlled accordingly, thereby realizing the over-temperature protection function of the motor.

[0081] This invention determines a second temperature threshold based on the current motor temperature and its rate of change. This adaptive adjustment of the second temperature threshold takes into account the influence of the current motor temperature and the rate of temperature rise. A derating factor is determined using the adaptively adjusted second temperature threshold to obtain a first torque. The second torque is determined by considering the influence of peak power. The smaller of the first and second torques is used to determine the actual torque limits for the motor under driving and generating conditions, respectively. These actual torque limits prevent permanent damage to the motor due to overheating and effectively mitigate the problems of winding copper losses and rapid temperature rise when peak power is exceeded. This ensures motor performance while extending its service life and also provides thermal protection during generating conditions.

[0082] According to an embodiment of the present invention, a motor control method embodiment is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0083] This embodiment also provides a motor control method, which can be applied to vehicle controllers such as microcontrollers (MCUs) and other control chips. Figure 2 This is a flowchart of a motor control method according to an embodiment of the present invention, such as... Figure 2 As shown, the process includes the following steps:

[0084] Step S201: Obtain the current motor temperature, current motor temperature change rate, current motor speed, and peak motor power. See details below. Figure 1 The relevant descriptions of step S101 shown will not be repeated here.

[0085] Step S202: When the current motor temperature is not less than the first temperature threshold, determine the second temperature threshold based on the current motor temperature and the current motor temperature change rate.

[0086] The second temperature threshold is greater than the first temperature threshold.

[0087] Specifically, step S202 includes:

[0088] Step S2021: Calibrate the temperature threshold corresponding to the motor overheating fault under different motor temperatures and motor temperature change rates to obtain the mapping relationship between different motor temperatures, motor temperature change rates and temperature thresholds.

[0089] Specifically, by conducting several tests on the same model of motor under different motor temperatures and different rates of temperature change, the temperature value at which the motor will overheat and fail can be obtained. Then, by taking the smaller or average value of the temperature values ​​obtained under the same conditions, the data can be integrated to calibrate the temperature threshold under different conditions, and thus obtain the mapping relationship between different motor temperatures, motor temperature change rates and temperature thresholds. For example, this mapping relationship can be stored in tabular form.

[0090] Step S2022: Based on the mapping relationship, determine the second temperature threshold corresponding to the current motor temperature and the current motor temperature change rate.

[0091] For example, the second temperature threshold corresponding to the current motor temperature and the current motor temperature change rate can be found in the table of the above-mentioned storage mapping relationship.

[0092] This invention provides an accurate mapping relationship between motor temperature, motor temperature change rate, and temperature threshold by calibrating the temperature threshold corresponding to the motor over-temperature fault under different motor temperatures and motor temperature change rates. Based on this mapping relationship, a second temperature threshold that conforms to the actual operating conditions of the motor and causes an over-temperature fault can be obtained, thus providing an accurate data basis for motor temperature protection, further ensuring motor performance while improving motor service life.

[0093] Step S203: When the current motor temperature is less than the second temperature threshold, calculate the derating factor based on the current motor temperature, the first temperature threshold, and the second temperature threshold.

[0094] Specifically, step S203 includes:

[0095] Step S2031: Calculate the first temperature difference between the current motor temperature and the first temperature threshold, and calculate the second temperature difference between the second temperature threshold and the first temperature threshold.

[0096] Step S2032: Determine the derating factor based on the ratio of the first temperature difference to the second temperature difference.

[0097] For example, assuming the current motor temperature is A, the first temperature threshold is B1, and the second temperature threshold is B2, then the above derating factor C = (A-B1) / (B1-B2).

[0098] This invention utilizes the ratio of the temperature difference between the real-time motor temperature and the first temperature threshold to the temperature difference between the second temperature threshold and the first temperature threshold to obtain the derating coefficient. This enables linear adjustment of the subsequent actual torque limit, ensuring the stability of the actual torque adjustment of the motor. It avoids the problem of drastic fluctuations in motor output power and a significant increase in battery energy consumption caused by large adjustments to motor torque, thereby improving the vehicle's driving range. At the same time, excessive torque adjustment can make the vehicle overly sensitive at low speeds, requiring more precise control from the driver and potentially leading to a sense of loss of control. Linear and stable adjustment of the actual torque limit of the motor can improve the user's driving experience during low-speed driving.

[0099] Step S204: Determine the current external characteristic torque value based on the current motor speed, and calculate the first torque based on the product of the current external characteristic torque value and the derating factor. See details below. Figure 1 The relevant description of step S104 shown will not be repeated here.

[0100] Step S205: Calculate the second torque based on the peak power, the current motor speed, and the derating factor.

[0101] Specifically, step S205 includes:

[0102] Step S2051: Calculate the current peak torque based on the peak power and the current motor speed.

[0103] Specifically, the current peak torque can be calculated based on the correspondence between power, speed, and torque.

[0104] Step S2052: Calculate the second torque based on the product of the current peak torque and the derating factor.

[0105] This invention calculates the current peak torque corresponding to the current motor speed using the motor's peak power, and then obtains the torque limit corresponding to the peak power by multiplying the current peak torque by the derating factor. This ensures that the motor does not exceed its peak power, thereby avoiding problems such as winding copper loss and rapid temperature rise, and further improving the service life of the motor.

[0106] Step S206: Based on the smaller value of the first torque and the second torque, determine the actual torque limit values ​​corresponding to the driving condition and the generating condition, respectively, and control the operation of the motor according to the actual torque limit values ​​corresponding to the driving condition and the generating condition, respectively.

[0107] Specifically, in step S206 above, the actual torque limits corresponding to the driving and power generation conditions are determined based on the smaller of the first torque and the second torque, including:

[0108] Step a1: Determine the smaller value between the first torque and the second torque as the maximum actual torque limit under the driving condition.

[0109] Step a2: The smaller of the first torque and the second torque is negativeized and determined as the minimum actual torque limit under the power generation condition.

[0110] This invention, by determining the smaller of the first torque and the second torque as the maximum actual torque limit under driving conditions, ensures that the motor can avoid overheating damage and extend its service life, regardless of whether it is operating at high or low speeds, as long as the operating torque meets the actual torque limit. Furthermore, by taking the negative of the smaller of the first torque and the second torque and determining it as the minimum actual torque limit under power generation conditions, the thermal protection function of the motor under power generation conditions is achieved.

[0111] In some optional implementations, before performing step a2, step S206 further includes the following steps:

[0112] Step a3: Determine whether the smaller of the first torque and the second torque is greater than the product of the current external characteristic torque value and the set limit coefficient.

[0113] The set limit coefficient is greater than 0 and less than or equal to 1. For example, this limit coefficient can be selected based on experience, such as 0.8.

[0114] Specifically, the current external characteristic torque value of the motor is the theoretically safe peak driving torque value that the motor can output at the current speed. Therefore, when limiting the torque of the motor, it is also necessary to consider the influence of the peak driving torque of the motor to avoid damage to the motor caused by excessive running torque.

[0115] Step a4: When the smaller of the first torque and the second torque is greater than the product of the current external characteristic torque value and the set limit coefficient, the minimum actual torque limit corresponding to the power generation condition is updated to the torque value after taking the negative of the product of the current external characteristic torque value and the set limit coefficient.

[0116] Furthermore, if the smaller of the first torque and the second torque is not greater than the product of the current external characteristic torque value and the set limit coefficient, then step a2 above is executed.

[0117] This invention further limits the minimum actual torque limit under power generation conditions by comparing the current external characteristic torque value of the motor with the product of a set limit coefficient, thereby preventing excessive motor operating torque from damaging the motor and further extending the motor's service life.

[0118] In some optional implementations, the motor control method provided by the embodiments of the present invention further includes the following steps:

[0119] Step b1: When the current motor temperature is not lower than the second temperature threshold, control the motor to output zero torque in both drive and generator modes.

[0120] This invention, by directly controlling the motor to output zero torque under both driving and generating conditions when the current motor temperature is not lower than a second temperature threshold, can quickly cool the motor, minimize motor damage, and extend the motor's service life.

[0121] In some optional implementations, the motor control method provided by the embodiments of the present invention further includes the following steps:

[0122] Step c1: When the current motor temperature is less than the first temperature threshold, determine the maximum actual torque limit corresponding to the drive condition as the current external characteristic torque value, and determine the minimum actual torque limit corresponding to the generator condition as the torque value after taking the negative of the current external characteristic torque value.

[0123] Specifically, when the motor temperature is less than the first temperature threshold, it means that there is no risk of overheating in the motor. Therefore, no additional restrictions need to be placed on the motor torque. As long as the motor torque operates within the current external characteristic torque value of the motor, that is, within the safe operating torque range, the motor operation can meet the driving requirements.

[0124] Step c2: Control the motor operation according to the maximum actual torque limit corresponding to the driving condition and the minimum torque limit corresponding to the power generation condition.

[0125] This invention improves the motor's torque capability and maximizes its performance by controlling the motor to operate at its current external characteristic torque value during driving and at the negative torque value during power generation when the current motor temperature is below a first temperature threshold, since there is no overheating problem.

[0126] The following will provide a detailed explanation of the specific working process of the motor control scheme provided in the embodiments of the present invention, using specific application examples.

[0127] For example, such as Figure 3 As shown, the process for determining the motor torque capacity includes:

[0128] S01: Real-time acquisition of motor temperature and motor speed.

[0129] Specifically, the motor temperature refers to the motor stator temperature, and the motor speed is obtained by decoding the feedback signal collected by the rotary transformer through software.

[0130] S02: When the motor temperature is below the first temperature threshold, the maximum and minimum torque output capability is 1.

[0131] Specifically, the maximum torque capability 1 at this time is the driving peak torque, which is the current external characteristic torque value mentioned above. The minimum torque capability 1 is the negative of the generating peak torque. The generating peak torque is equal to the driving peak torque, meaning that the motor torque is not limited when the motor temperature is below the first temperature threshold.

[0132] S03: Calculate the rate of temperature increase based on the temperature to obtain the second temperature threshold.

[0133] Specifically, the motor temperature t0 is acquired in real time during each execution cycle, and the acquired temperature is delayed to obtain t1. The difference between t1 and t0 is the motor temperature change rate. The second temperature threshold is then obtained by looking up the table based on the motor temperature change rate.

[0134] S04: When the motor temperature exceeds the first temperature threshold but is lower than the second temperature threshold, calculate the maximum and minimum torque capacity 1 based on the relationship between the external characteristic torque and the motor temperature.

[0135] Specifically, the derating factor and the maximum / minimum torque capability value 1 are calculated based on the current external characteristic torque value, the current motor temperature, the first temperature threshold, and the second temperature threshold. The derating factor is the ratio of the difference between the current temperature and the first temperature threshold to the difference between the second temperature threshold and the first temperature threshold. The maximum / minimum torque capability 1 is the derating factor multiplied by the external characteristic torque. When the motor temperature is greater than or equal to the first temperature threshold, the fault flag is set to 1; when the motor temperature is lower than the first temperature threshold minus the offset, the fault flag is set to 0.

[0136] S05: If the current motor temperature reaches the second temperature threshold, the motor output torque capability 1 is 0.

[0137] Specifically, at this time, the maximum torque capability 1 and the minimum torque capability 1 are 0, that is, when the motor temperature is greater than or equal to the second temperature threshold, the derating factor is 0.

[0138] S06: Derating factor, peak power, motor speed calculation of maximum and minimum torque capacity 2.

[0139] Specifically, the maximum torque capability 2 refers to the maximum torque capability trq calculated at the current motor speed based on the correspondence between peak power, speed, and torque, and then the maximum torque capability 2 is obtained by multiplying trq by the derating factor obtained in S04. The minimum torque capability 2 is the maximum torque capability 2 with a negative sign.

[0140] S07: The smaller of torque capacity 1 and torque capacity 2 is used for output.

[0141] Specifically, based on the maximum torque capability 1 and minimum torque capability 1 calculated according to S02, S04, and S05, and then based on the maximum torque capability 2 and minimum torque capability 2 calculated according to S06, the final maximum and minimum torque capabilities are calculated. The smaller of maximum torque capability 1 and maximum torque capability 2 is taken to obtain the final maximum torque capability, which is used to limit the actual torque of the motor under drive conditions, effectively preventing the motor temperature from rising continuously and rapidly. The smaller of the absolute values ​​of minimum torque capability 1 and minimum torque capability 2 is taken, and the result is denoted as torque capability 3. The peak drive torque is multiplied by a set limit coefficient to obtain torque capability 4. The smaller of torque capability 3 and torque capability 4 is then taken as the negative number to obtain the final minimum torque capability, which is used to limit the actual torque of the motor under generator conditions, effectively preventing the motor temperature from rising continuously and rapidly.

[0142] For example, the relationship between the actual torque limit of the motor and temperature under driving and generating conditions is as follows: Figure 4 As shown. Figure 4 China T nax1 T represents the peak driving torque of the motor. max2 This represents the peak torque generated by the motor, and T max1 =T max2 t1 and t2 represent the first temperature threshold and the second temperature threshold, respectively.

[0143] This embodiment also provides a motor control device for implementing the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0144] This invention provides a motor control device, such as... Figure 5 As shown, the device includes:

[0145] The acquisition module 501 is used to acquire the current motor temperature, current motor temperature change rate, current motor speed, and peak power of the motor.

[0146] The first processing module 502 is used to determine a second temperature threshold based on the current motor temperature and the current motor temperature change rate when the current motor temperature is not less than the first temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold.

[0147] The second processing module 503 is used to calculate the derating factor based on the current motor temperature, the first temperature threshold and the second temperature threshold when the current motor temperature is less than the second temperature threshold.

[0148] The third processing module 504 is used to determine the current external characteristic torque value based on the current motor speed, and to calculate the first torque based on the product of the current external characteristic torque value and the derating factor.

[0149] The fourth processing module 505 is used to calculate the second torque based on the peak power, the current motor speed and the derating factor;

[0150] The fifth processing module 506 is used to determine the actual torque limit values ​​corresponding to the driving condition and the generating condition based on the smaller value of the first torque and the second torque, and to control the operation of the motor according to the actual torque limit values ​​corresponding to the driving condition and the generating condition.

[0151] In some optional implementations, the first processing module 502 includes:

[0152] The first processing unit is used to calibrate the temperature threshold corresponding to the motor over-temperature fault under the motor temperature change rate, and to obtain the mapping relationship between different motor temperatures, motor temperature change rate and temperature threshold.

[0153] The second processing unit is used to determine the current motor temperature and the second temperature threshold corresponding to the current motor temperature change rate based on the mapping relationship.

[0154] In some optional implementations, the second processing module 503 includes:

[0155] The third processing unit is used to calculate the first temperature difference between the current motor temperature and the first temperature threshold, and to calculate the second temperature difference between the second temperature threshold and the first temperature threshold.

[0156] The fourth processing unit is used to determine the derating factor based on the ratio of the first temperature difference to the second temperature difference.

[0157] In some optional implementations, the fourth processing module 505 includes:

[0158] The fifth processing unit is used to calculate the current peak torque based on the peak power and the current motor speed;

[0159] The sixth processing unit is used to calculate the second torque based on the product of the current peak torque and the derating factor.

[0160] In some optional implementations, the fifth processing module 506 includes:

[0161] The seventh processing unit is used to determine the smaller value between the first torque and the second torque as the maximum actual torque limit under the driving condition.

[0162] The eighth processing unit is used to take the negative of the smaller value between the first torque and the second torque and determine it as the minimum actual torque limit under the power generation condition.

[0163] In some optional embodiments, the fifth processing module 506 further includes:

[0164] The ninth processing unit is used to determine whether the smaller value of the first torque and the second torque is greater than the product of the current external characteristic torque value and the set limit coefficient, wherein the set limit coefficient is greater than 0 and less than or equal to 1;

[0165] The tenth processing unit is used to update the minimum actual torque limit corresponding to the power generation condition to the negative of the product of the current external characteristic torque value and the set limit coefficient when the smaller of the first torque and the second torque is greater than the product of the current external characteristic torque value and the set limit coefficient.

[0166] In some optional embodiments, the motor control device provided in this invention further includes:

[0167] The sixth processing module is used to control the motor to output zero torque in both drive and generator modes when the current motor temperature is not lower than the second temperature threshold.

[0168] In some optional embodiments, the motor control device provided in this invention further includes:

[0169] The seventh processing module is used to determine the maximum actual torque limit corresponding to the driving condition as the current external characteristic torque value when the current motor temperature is less than the first temperature threshold, and to determine the minimum actual torque limit corresponding to the power generation condition as the torque value after taking the negative of the current external characteristic torque value.

[0170] The eighth control module is used to control the operation of the motor according to the maximum actual torque limit corresponding to the driving condition and the minimum actual torque limit corresponding to the generating condition.

[0171] The further functional descriptions of the above modules and units are the same as those in the corresponding method embodiments described above, and will not be repeated here.

[0172] This invention also provides a vehicle, which includes a controller, such as... Figure 6As shown, the controller includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions that execute within the computer device, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 6 Take a processor 10 as an example.

[0173] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0174] The memory 20 stores instructions executable by at least one processor 10 to cause at least one processor 10 to perform the method shown in the above embodiments.

[0175] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device as shown by a landing page for an app. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, which can be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0176] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0177] The controller also includes a communication interface 30 for the vehicle to communicate with other devices or communication networks.

[0178] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code, which, when accessed and executed by the computer, processor, or hardware, implements the methods shown in the above embodiments.

[0179] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0180] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A motor control method, characterized in that, The method includes: Obtain the current motor temperature, current motor temperature change rate, current motor speed, and peak motor power; When the current motor temperature is not less than the first temperature threshold, a second temperature threshold is determined based on the current motor temperature and the current motor temperature change rate, wherein the second temperature threshold is greater than the first temperature threshold; When the current motor temperature is lower than the second temperature threshold, a derating factor is calculated based on the current motor temperature, the first temperature threshold, and the second temperature threshold. The current external characteristic torque value is determined based on the current motor speed, and the first torque is calculated based on the product of the current external characteristic torque value and the derating factor. The second torque is calculated based on the peak power, the current motor speed, and the derating factor. Based on the smaller value between the first torque and the second torque, the actual torque limit values ​​corresponding to the driving condition and the generating condition are determined respectively, and the motor is operated and controlled according to the actual torque limit values ​​corresponding to the driving condition and the generating condition respectively. The step of determining the actual torque limits for the driving and power generation conditions based on the smaller of the first torque and the second torque includes: The smaller value between the first torque and the second torque is determined as the maximum actual torque limit under the driving condition; The smaller of the first torque and the second torque is negativeized and determined as the minimum actual torque limit under the power generation condition. Determine whether the smaller of the first torque and the second torque is greater than the product of the current external characteristic torque value and a set limit coefficient, wherein the set limit coefficient is greater than 0 and less than or equal to 1; When the smaller of the first torque and the second torque is greater than the product of the current external characteristic torque value and the set limit coefficient, the minimum actual torque limit corresponding to the power generation condition is updated to the negative of the product of the current external characteristic torque value and the set limit coefficient, so as to avoid damage to the motor caused by excessive motor operating torque.

2. The method according to claim 1, characterized in that, The step of determining the second temperature threshold based on the current motor temperature and the current motor temperature change rate includes: The temperature thresholds corresponding to the motor overheating fault under different motor temperatures and motor temperature change rates are calibrated to obtain the mapping relationship between different motor temperatures, motor temperature change rates and temperature thresholds. Based on the mapping relationship, a second temperature threshold corresponding to the current motor temperature and the current motor temperature change rate is determined.

3. The method according to claim 1, characterized in that, The calculation of the derating factor based on the current motor temperature, the first temperature threshold, and the second temperature threshold includes: Calculate the first temperature difference between the current motor temperature and the first temperature threshold, and calculate the second temperature difference between the second temperature threshold and the first temperature threshold; The derating factor is determined based on the ratio of the first temperature difference to the second temperature difference.

4. The method according to claim 1, characterized in that, The calculation of the second torque based on the peak power, the current motor speed, and the derating factor includes: Calculate the current peak torque based on the peak power and the current motor speed; The second torque is calculated based on the product of the current peak torque and the derating factor.

5. The method according to claim 1, characterized in that, The method further includes: When the current motor temperature is not less than the second temperature threshold, the motor is controlled to output zero torque in both driving and generating modes.

6. The method according to claim 1, characterized in that, When the current motor temperature is less than the first temperature threshold, the maximum actual torque limit corresponding to the driving condition is determined to be the current external characteristic torque value, and the minimum actual torque limit corresponding to the power generation condition is determined to be the torque value after taking the negative of the current external characteristic torque value. The motor is operated and controlled according to the maximum actual torque limit corresponding to the driving condition and the minimum torque limit corresponding to the power generation condition.

7. A motor control device, characterized in that, The device includes: The acquisition module is used to acquire the current motor temperature, current motor temperature change rate, current motor speed, and peak power of the motor. A first processing module is configured to determine a second temperature threshold based on the current motor temperature and the current motor temperature change rate when the current motor temperature is not less than a first temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold. The second processing module is used to calculate a derating factor based on the current motor temperature, the first temperature threshold and the second temperature threshold when the current motor temperature is less than the second temperature threshold. The third processing module is used to determine the current external characteristic torque value based on the current motor speed, and to calculate the first torque based on the product of the current external characteristic torque value and the derating factor; The fourth processing module is used to calculate the second torque based on the peak power, the current motor speed, and the derating factor; The fifth processing module is used to determine the actual torque limit values ​​corresponding to the driving condition and the generating condition based on the smaller value of the first torque and the second torque, and to control the operation of the motor according to the actual torque limit values ​​corresponding to the driving condition and the generating condition. The fifth processing module includes: The seventh processing unit is used to determine the smaller value between the first torque and the second torque as the maximum actual torque limit under the driving condition. The eighth processing unit is used to take the negative of the smaller value between the first torque and the second torque and determine it as the minimum actual torque limit under the power generation condition. The fifth processing module also includes: The ninth processing unit is used to determine whether the smaller value of the first torque and the second torque is greater than the product of the current external characteristic torque value and the set limit coefficient, wherein the set limit coefficient is greater than 0 and less than or equal to 1; The tenth processing unit is used to update the minimum actual torque limit corresponding to the power generation condition to the negative of the product of the current external characteristic torque value and the set limit coefficient when the smaller of the first torque and the second torque is greater than the product of the current external characteristic torque value and the set limit coefficient, so as to avoid damage to the motor caused by excessive motor operating torque.

8. A vehicle, characterized in that, The vehicle includes: a controller, the controller comprising: A memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, the processor executing the computer instructions to perform the method of any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing a computer to perform the method of any one of claims 1 to 6.

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