Maximum torque determination method of oil-cooled motor, terminal and storage medium

Abstract

The invention discloses a method for determining the maximum torque of an oil-cooled motor, a terminal and a storage medium, and the method comprises the steps: obtaining the peak torque and continuous torque of the oil-cooled motor at the current rotating speed according to the current water temperature of a water-cooled loop in response to the situation that the flow of an oil-cooled loop is smaller than a flow threshold value, and determining the maximum torque of the oil-cooled motor at the current rotating speed according to the current oil temperature of the oil-cooled loop; determining a first maximum torque corresponding to the current rotating speed of the oil-cooled motor according to the current rotating speed of the oil-cooled motor and the peak torque and / or the continuous torque; acquiring a limited power coefficient of the oil-cooled motor, and determining a second maximum torque of the oil-cooled motor at the current rotating speed by using the peak torque, the continuous torque and the limited power coefficient; wherein the oil-cooled motor can continuously and safely run under the second maximum torque; and selecting the minimum one from the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current rotating speed. According to the scheme, on the premise that safe operation of the oil-cooled motor is guaranteed, the output performance of the oil-cooled motor is fully released.

Description

Technical Field

[0001] The present application relates to the technical field of oil-cooled motor fault protection, and in particular to a method for determining a maximum torque of an oil-cooled motor, a terminal, and a storage medium. Background Art

[0002] According to the different cooling methods, motors can be divided into air cooling, water cooling and oil cooling. Compared with air cooling and water cooling, oil cooling can cool the heat source inside the motor through lubricating oil (cooling oil) to achieve better cooling effect. In recent years, oil-cooled motors have been widely used due to their high cooling efficiency and small size.

[0003] The cooling effect of the oil-cooled motor is closely related to the flow rate provided by the oil cooling circuit. If the oil cooling circuit fails (is abnormal), the cooling effect of the oil-cooled motor will be greatly reduced. In order to ensure that the oil-cooled motor parts do not overheat, the oil-cooled motor needs to be derated for protection. In related technologies, conservative derated protection schemes are often used, which excessively reduce the maximum torque that the oil-cooled motor can output, seriously affecting the output performance of the oil-cooled motor and causing poor user experience. Summary of the invention

[0004] The present application provides a maximum torque method, terminal and storage medium for an oil-cooled motor.

[0005] A technical solution adopted by the present application is to provide a maximum torque method for an oil-cooled motor, wherein the oil-cooled motor is located in an oil cooling circuit, and the oil cooling circuit performs heat exchange with a water cooling circuit; the method comprises:

[0006] In response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtaining the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determining the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or the continuous torque;

[0007] Obtaining the power limit coefficient of the oil-cooled motor, and determining the second maximum torque of the oil-cooled motor at the current speed by using the peak torque, the continuous torque and the power limit coefficient; wherein the oil-cooled motor can continue to operate safely at the second maximum torque;

[0008] The smallest one of the first maximum torque and the second maximum torque is selected as the target maximum torque of the oil-cooled motor at the current speed.

[0009] Optionally, according to the current water temperature of the water cooling circuit, the peak torque and continuous torque of the oil-cooled motor at the current speed are obtained, including:

[0010] Obtain the target continuous external characteristic curve and target peak external characteristic curve of the oil-cooled motor under the current water temperature;

[0011] The continuous torque is obtained from the target continuous external characteristic curve using the current rotation speed; and the peak torque is obtained from the target peak external characteristic curve.

[0012] Optionally, a target continuous external characteristic curve and a target peak external characteristic curve of the oil-cooled motor under the current water temperature are obtained, including:

[0013] Obtain a reference continuous external characteristic curve and a reference peak external characteristic curve of the oil-cooled motor under reference water temperature;

[0014] Determine the water temperature coefficient using the reference water temperature and the current water temperature;

[0015] The target continuous external characteristic curve is obtained by using the water temperature coefficient and the reference continuous external characteristic curve; and the target peak external characteristic curve is obtained by using the water temperature coefficient and the reference peak external characteristic curve.

[0016] Optionally, determining a first maximum torque corresponding to the oil-cooled motor at a current speed according to a current oil temperature of the oil cooling circuit, and a peak torque and / or a continuous torque includes:

[0017] In response to the current oil temperature being less than or equal to a first threshold temperature, taking the peak torque as a first maximum torque;

[0018] In response to the current oil temperature being greater than a first threshold temperature and less than or equal to a second threshold temperature, the first maximum torque is less than the peak torque and greater than or equal to the continuous torque;

[0019] In response to the current oil temperature being greater than a second threshold temperature, the first maximum torque is less than the continuous torque.

[0020] Optionally, obtain the power limit factor of the oil-cooled motor, including:

[0021] The initial time coefficient is determined by using the initial water temperature of the water cooling circuit, the initial oil temperature of the oil cooling circuit, and the initial temperature of the oil cooling motor when the flow rate of the oil cooling circuit is less than the flow rate threshold;

[0022] Using the initial time factor, determine the power limit factor.

[0023] Optionally, the initial time coefficient is used to determine the power limit coefficient, including:

[0024] Obtaining a first operating time when the peak torque corresponds to no temperature rise risk, and obtaining a second operating time when the average of the peak torque and the continuous torque corresponds to no temperature rise risk;

[0025] Obtaining a third operating time for the oil-cooled motor to reach a constant temperature when the continuous torque is reduced from one-half of the continuous torque; and a fourth operating time for the oil-cooled motor to reach a constant temperature when the continuous torque is reduced from zero torque;

[0026] Obtaining a standard time coefficient using the first running time, the second running time, the third running time, and the fourth running time;

[0027] The power limit factor is determined using the initial time factor and the standard time factor.

[0028] Optionally, the power limit coefficient is determined by using the initial time coefficient and the standard time coefficient, including:

[0029] The peak torque is used to obtain the first time conversion coefficient; the average of the peak torque and the continuous torque is used to obtain the second time conversion coefficient; the half of the continuous torque is used to obtain the third time conversion coefficient, and the zero torque is used to obtain the fourth time conversion coefficient;

[0030] Obtaining an operating condition time coefficient using the first time conversion coefficient, the second time conversion coefficient, the third time conversion coefficient, the fourth time conversion coefficient and their respective corresponding actual operating times;

[0031] The power limit coefficient is determined using the initial time coefficient, standard time coefficient and operating condition time coefficient.

[0032] Optionally, before the step of selecting the smallest one of the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current speed, the method includes:

[0033] Get the current motor temperature of the oil-cooled motor;

[0034] In response to the current motor temperature exceeding the target temperature threshold, a third maximum torque is determined according to the current speed of the oil-cooled motor; wherein the target temperature threshold is obtained by lowering the default temperature threshold when the flow rate of the oil cooling circuit is greater than or equal to the flow rate threshold;

[0035] Selecting the smallest one of the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current speed includes:

[0036] The smallest one among the first maximum torque, the second maximum torque and the third maximum torque is selected as the target maximum torque of the oil-cooled motor at the current speed.

[0037] Another technical solution adopted by the present application is to provide a terminal device, the terminal device comprising a memory and a processor connected to the memory;

[0038] The memory is used to store program data, and the processor is used to execute the program data to implement the maximum torque determination method of the oil-cooled motor as described above.

[0039] Another technical solution adopted by the present application is to provide a computer storage medium, wherein the computer storage medium is used to store program data, and when the program data is executed by a computer, it is used to implement the maximum torque determination method of the oil-cooled motor as described above.

[0040] The beneficial effects of the present application are as follows: in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, the peak torque and continuous torque of the oil-cooled motor at the current speed are obtained according to the current water temperature of the water cooling circuit, and the first maximum torque corresponding to the oil-cooled motor at the current speed is determined according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; the power limit coefficient of the oil cooling motor is obtained, and the peak torque, continuous torque and power limit coefficient are used to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; the smallest one of the first maximum torque and the second maximum torque is selected as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil cooling motor provided by the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 It is a flow chart of an embodiment of a method for determining the maximum torque of an oil-cooled motor provided by the present application;

[0043] Figure 2 is a schematic diagram of an embodiment of the relationship between oil temperature and the first maximum torque;

[0044] Figure 3 It is a structural diagram of an embodiment of a terminal device provided by the present application;

[0045] Figure 4 It is a structural diagram of an embodiment of a computer storage medium provided by the present application. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] The terms "first", "second", etc. in this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods or devices.

[0048] In addition, although the terms "first", "second", etc. are used many times in this application to describe various data (or various applications or various instructions or various operations), etc., these data (or applications or instructions or operations) should not be limited by these terms. These terms are only used to distinguish one type of data (or application or instruction or operation) from another type of data (or application or instruction or operation).

[0049] Please refer to Figure 1 , Figure 1 It is a flow chart of an embodiment of a method for determining the maximum torque of an oil-cooled motor provided in the present application.

[0050] like Figure 1 As shown, the method for determining the maximum torque of an oil-cooled motor in an embodiment of the present application may specifically include the following steps:

[0051] S1, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtain the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determine the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque.

[0052] Among them, the oil-cooled motor is located in an oil cooling circuit, and the oil cooling circuit and the water cooling circuit perform heat exchange.

[0053] The maximum torque determination method of the oil-cooled motor provided in the present application is mainly performed by a torque determination device. In some embodiments, the torque determination device may be the motor controller itself. In some embodiments, the torque determination device may be a device that is communicatively connected to the motor controller. For example, the device may be a device for monitoring images, a user equipment (UE), a mobile device, a user terminal, a terminal, a cellular phone, a cordless phone, a personal digital assistant (PDA), a handheld device, a computing device, a vehicle-mounted device, a wearable device, and an autonomous vehicle, a robot, a security system, or any one or more products of glasses and helmets for augmented reality or virtual reality. In some possible implementations, the maximum torque determination method of the oil-cooled motor may be implemented by a processor calling computer-readable instructions stored in a memory.

[0054] In some embodiments, the oil cooling circuit and the water cooling circuit exchange heat through a heat exchanger. Furthermore, on one side of the oil cooling circuit, the output end of the heat exchanger is connected to the oil channel input end of the oil-cooled motor, the oil channel output end of the oil-cooled motor is connected to the input end of the oil pump, and the output end of the oil pump is connected to the input end of the heat exchanger. The lubricating oil (cooling oil) cools the stator winding and rotor inside the oil-cooled motor, and the lubricating oil that absorbs heat flows out from the oil channel output end of the oil-cooled motor, and after being pressurized by the oil pump, the lubricating oil that absorbs heat passes through the heat exchanger and brings heat to the water cooling circuit, thereby re-cooling the lubricating oil.

[0055] Specifically, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, the torque determination device obtains the peak torque and continuous torque of the oil-cooled motor at the current speed based on the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed based on the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque.

[0056] It should be noted that the scenario targeted by this application is the scenario when the oil-cooled motor is in operation.

[0057] Optionally, the flow rate of the oil cooling circuit being less than the flow rate threshold may mean that the oil cooling circuit is blocked, or that an oil pump for pumping lubricating oil (cooling oil) in the oil cooling circuit fails. Specifically, the oil pump failure may mean that the oil pump stops working, or that the pumping volume of the oil pump per unit time is less than the pumping volume required by the oil cooling circuit to ensure normal heat dissipation.

[0058] In some embodiments, the pumping volume of the oil pump per unit time can be determined by the rotation speed of the oil pump.

[0059] In some possible embodiments, the oil pump is connected to the oil pump controller (the motor controller corresponding to the oil pump motor) in communication, and the torque determination device determines whether the flow rate of the oil cooling circuit is less than the flow rate threshold value according to the current speed feedback from the oil pump. In some possible embodiments, in response to the oil pump losing communication with the main controller, or the main controller receiving an error signal sent by the oil pump, the torque determination device determines that the oil pump has failed. In some possible embodiments, the oil pump is connected to the motor controller of the oil cooling motor in communication.

[0060] When the flow rate of the oil cooling circuit is less than the flow threshold, the motor dissipates heat naturally through the motor housing. It is understandable that the rate of natural heat dissipation is negatively correlated with the ambient temperature. The higher the ambient temperature, the lower the heat dissipation rate. Generally speaking, a temperature sensor for collecting ambient temperature is not specially set on the outside of the oil-cooled motor. It is understandable that because the water cooling circuit still absorbs the heat generated by the oil cooling circuit to a certain extent, the ambient temperature is lower than the current water temperature of the water cooling circuit. In this embodiment, the water temperature can be used to indirectly reflect the size of the ambient temperature.

[0061] In some embodiments, the current water temperature of the water cooling circuit can be determined by a temperature sensor disposed inside the water cooling circuit. The current oil temperature of the oil cooling circuit can be determined by a temperature sensor disposed inside the oil cooling circuit. Exemplarily, the temperature sensor is a thermocouple.

[0062] The peak torque of an oil-cooled motor at the current speed refers to the maximum torque that the oil-cooled motor can work for a short time at the current speed under the current water temperature, provided that the components of the oil-cooled motor do not overheat.

[0063] The continuous torque of an oil-cooled motor at the current speed refers to the maximum torque that the oil-cooled motor can continuously work at the current speed under the current water temperature and on the premise that the components of the oil-cooled motor do not overheat.

[0064] It can be understood that at the same speed, the greater the torque, the greater the heat generated by the oil-cooled motor, and therefore, the continuous torque is less than the peak torque.

[0065] In some application scenarios, the maximum torque determination method of the oil-cooled motor provided in the present application can be applied to the oil-cooled electric drive. In some embodiments, the oil-cooled electric drive is a three-in-one oil-cooled electric drive, including an oil-cooled motor and a reducer. Among them, a reducer oil channel is provided in the reducer, and the lubricating oil enters the oil-cooled motor through the reducer oil channel to cool the stator winding and the rotor of the oil-cooled motor. After that, the lubricating oil flows back to the reducer oil channel and flows out from the reducer oil channel. The output end of the reducer oil channel is connected to the input end of the heat exchanger, and the output end of the heat exchanger is connected to the input end of the reducer oil channel, forming an oil-cooling circuit for the circulation of the lubricating oil, wherein the other side of the heat exchanger is connected to the water cooling circuit, which is used to take away the heat in the oil cooling circuit.

[0066] In some embodiments, the components of the oil-cooled motor can be divided into first type components and second type components, wherein the first type components are components that can be cooled by contact with lubricating oil (such as the oil pan and motor rotor of the oil-cooled motor), and the second type components are components that cannot be cooled by contact with lubricating oil (such as the motor stator and bearings).

[0067] To a certain extent, the oil temperature of the oil cooling circuit can indirectly reflect the temperature rise of the first type of components. Based on this, the torque determination device can use the current oil temperature of the oil cooling circuit to limit the maximum torque of the oil-cooled motor to protect the first type of components from overheating.

[0068] It should be noted that the first maximum torque is used to reflect the maximum torque that the oil-cooled motor can output when the flow rate of the oil cooling circuit is less than the flow rate threshold and the first type of component does not exceed the safe operating temperature.

[0069] S2, obtaining the power limit coefficient of the oil-cooled motor, and determining the second maximum torque of the oil-cooled motor at the current speed by using the peak torque, the continuous torque and the power limit coefficient.

[0070] Among them, the oil-cooled motor can continue to operate safely at the second maximum torque.

[0071] Specifically, the torque determination device obtains the limited power coefficient of the oil-cooled motor, and determines the second maximum torque of the oil-cooled motor at the current speed by using the peak torque, the continuous torque and the limited power coefficient.

[0072] In some embodiments, the second maximum torque satisfies the following relationship:

[0073] T2=T C +(T P -T C )*(1-α)

[0074] Among them, T2 is the second maximum torque, T C is the continuous torque, T P is the peak torque, and α is the limiting power factor.

[0075] The lower limit of the power limit coefficient is 0, and the upper limit is 1.

[0076] It is understandable that when the flow rate of the oil cooling circuit is less than the flow rate threshold, the second type component can no longer dissipate heat by contact with the lubricating oil and can only dissipate heat passively. The oil temperature of the oil cooling circuit cannot reflect the temperature rise of the second type component. Therefore, another method is needed to determine the working condition of the second type component. This embodiment takes into account the temperature rise of the motor under the combined effect of heat generation and heat dissipation under actual operating conditions when the flow rate of the oil cooling circuit is less than the flow rate threshold, and sets the power limit protection coefficient.

[0077] It should be noted that the second maximum torque is used to reflect the maximum torque at which the second type component does not exceed the safe operating temperature when the flow rate of the oil cooling circuit is less than the flow rate threshold.

[0078] S3, selecting the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current speed.

[0079] Specifically, the torque determination device selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current speed.

[0080] In this embodiment, the first maximum torque refers to the maximum torque of the first type component that does not exceed the safe operating temperature, and the second maximum torque refers to the maximum torque of the second type component that does not exceed the safe operating temperature. The torque determination device selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque. The target maximum torque ensures that both the first type component and the second type component do not exceed the safe operating temperature, that is, ensures that the oil-cooled motor can operate safely at the current speed.

[0081] The above scheme, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtains the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; obtains the power limit coefficient of the oil cooling motor, and uses the peak torque, continuous torque and power limit coefficient to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil-cooled motor provided in the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience.

[0082] Another embodiment of the method for determining the maximum torque of an oil-cooled motor provided by the present application may specifically include the following steps:

[0083] S11, in response to the flow rate of the oil cooling circuit being less than a flow rate threshold, obtaining a target continuous external characteristic curve and a target peak external characteristic curve of the oil-cooled motor at a current water temperature.

[0084] Specifically, in response to the flow rate of the oil cooling circuit being less than a flow rate threshold, the torque determination device obtains a target continuous external characteristic curve and a target peak external characteristic curve of the oil-cooled motor at the current water temperature.

[0085] In some possible embodiments, the target continuous external characteristic curve can be obtained by simulating or pre-calibrating the oil-cooled motor. Similarly, the target peak external characteristic curve can also be obtained by simulating or pre-calibrating the oil-cooled motor.

[0086] In some embodiments, the target continuous external characteristic curve at the current water temperature can be represented by the following table:

[0087]

[0088] Wherein, H_w is the current water temperature. The target continuous external characteristic curve is used to represent the relationship between the motor speed and continuous torque at which the first type of components of the oil-cooled motor can operate sustainably without the risk of temperature rise.

[0089] In some embodiments, the target peak external characteristic curve at the current water temperature can be represented by the following table:

[0090]

[0091] The target continuous external characteristic curve is used to represent the relationship between the motor speed and the continuous torque of the first type of components of the oil-cooled motor without the risk of temperature rise and capable of short-term operation.

[0092] Exemplarily, a short time may refer to any one of 0.5 min, 1 min, 1.5 min, 2 min, 2.5 min, 3 min, 3.5 min, 4 min, 4.5 min, and 5 min, which is not limited here. In some possible embodiments, a short time may refer to less than 0.5 min.

[0093] S12, obtaining a continuous torque from a target continuous external characteristic curve using the current rotation speed; and obtaining a peak torque from a target peak external characteristic curve.

[0094] Specifically, the torque determination device obtains the continuous torque corresponding to the current speed from the target continuous external characteristic curve, and obtains the peak torque corresponding to the current speed from the target peak external characteristic curve.

[0095] Exemplarily, the current water temperature is H_w, the current speed is 2000r / min, the corresponding continuous torque is T_w_c3, and the corresponding peak torque is T_w_p3.

[0096] S13, determining a first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or the continuous torque.

[0097] S14, obtaining a power limit coefficient of the oil-cooled motor, and determining a second maximum torque of the oil-cooled motor at a current speed by using the peak torque, the continuous torque and the power limit coefficient.

[0098] Among them, the oil-cooled motor can continue to operate safely at the second maximum torque.

[0099] S15, selecting the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current rotation speed.

[0100] The above scheme, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtains the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; obtains the power limit coefficient of the oil cooling motor, and uses the peak torque, continuous torque and power limit coefficient to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil-cooled motor provided in the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience.

[0101] Another embodiment of the method for determining the maximum torque of an oil-cooled motor provided by the present application may specifically include the following steps:

[0102] S21, in response to the flow rate of the oil cooling circuit being less than a flow rate threshold, obtaining a reference continuous external characteristic curve and a reference peak external characteristic curve of the oil-cooled motor at a reference water temperature.

[0103] Specifically, in response to the flow rate of the oil cooling circuit being less than a flow rate threshold, the torque determination device obtains a reference continuous external characteristic curve and a reference peak external characteristic curve of the oil-cooled motor at a reference water temperature.

[0104] Optionally, the reference continuous external characteristic curve can be obtained by simulating or pre-calibrating the oil-cooled motor. Similarly, the reference peak external characteristic curve can be obtained by simulating or pre-calibrating the oil-cooled motor.

[0105] In some embodiments, at the reference water temperature, the reference continuous external characteristic curve and the reference peak external characteristic curve of the oil-cooled motor can be represented by the following table:

[0106]

[0107] Among them, H_w0 is the reference water temperature.

[0108] It can be understood that the reference continuous external characteristic curve is used to indicate the maximum torque at different speeds under the reference water temperature, under the premise that the first category components of the oil-cooled motor are not overheated, and the motor is in continuous operation. The reference peak external characteristic curve is used to indicate the maximum torque at different speeds under the reference water temperature, under the premise that the first category components of the oil-cooled motor are not overheated, and the motor is in short-term operation.

[0109] S22, determining a water temperature coefficient using a reference water temperature and a current water temperature.

[0110] In some application scenarios, the continuous external characteristic curves corresponding to different water temperatures will be different. Similarly, the peak external characteristic curves corresponding to different water temperatures will be different.

[0111] In this embodiment, the continuous external characteristic curves corresponding to different water temperatures have a certain multiplier relationship. Therefore, the target continuous external characteristic curve corresponding to the current water temperature can be determined by using the water temperature coefficient corresponding to the current water temperature and the benchmark continuous external characteristic curve corresponding to the benchmark water temperature; and the target peak external characteristic curve corresponding to the current water temperature can be determined by using the water temperature coefficient and the benchmark peak external characteristic curve corresponding to the benchmark water temperature.

[0112] Specifically, the torque determination device obtains the corresponding water temperature coefficient under different water temperatures by simulating or pre-calibrating the oil-cooled motor.

[0113] In some application scenarios, the torque determination device establishes a relationship curve between the water temperature coefficient and the water temperature.

[0114] S23, using the water temperature coefficient and the reference continuous external characteristic curve to obtain a target continuous external characteristic curve; and using the water temperature coefficient and the reference peak external characteristic curve to obtain a target peak external characteristic curve.

[0115] Specifically, the torque determination device calculates the product of the water temperature coefficient and the reference continuous external characteristic curve to obtain the target continuous external characteristic curve. Similarly, the torque determination device calculates the product of the water temperature coefficient and the reference peak external characteristic curve to obtain the target peak external characteristic curve.

[0116] In some embodiments, in order to more accurately reflect the relationship between continuous external characteristic curves at different water temperatures, the water temperature coefficient includes a first water temperature coefficient. Similarly, in order to more accurately reflect the relationship between peak external characteristic curves at different water temperatures, the water temperature coefficient includes a second water temperature coefficient.

[0117] Specifically, the torque determination device calculates the product of the first water temperature coefficient and the reference continuous external characteristic curve to obtain the target continuous external characteristic curve. Similarly, the torque determination device calculates the product of the second water temperature coefficient and the reference peak external characteristic curve to obtain the target peak external characteristic curve.

[0118] S24, determining a first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or the continuous torque.

[0119] S25, obtaining a power limit coefficient of the oil-cooled motor, and determining a second maximum torque of the oil-cooled motor at a current speed by using the peak torque, the continuous torque, and the power limit coefficient.

[0120] Among them, the oil-cooled motor can continue to operate safely at the second maximum torque.

[0121] S26, selecting the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current speed.

[0122] The above scheme, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtains the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; obtains the power limit coefficient of the oil cooling motor, and uses the peak torque, continuous torque and power limit coefficient to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil-cooled motor provided in the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience.

[0123] Another embodiment of the method for determining the maximum torque of an oil-cooled motor provided by the present application may specifically include the following steps:

[0124] S31, in response to the flow rate of the oil cooling circuit being less than a flow rate threshold, obtaining the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit.

[0125] S32, in response to the current oil temperature being less than or equal to the first threshold temperature, taking the peak torque as the first maximum torque.

[0126] See also Figure 2 In response to the current oil temperature being less than or equal to the first threshold temperature, the torque determination device uses the peak torque corresponding to the current water temperature and the current speed as the first maximum torque of the oil-cooled motor.

[0127] It can be understood that since the current oil temperature is lower than the first threshold temperature, it means that the temperature rise of the first type of components is ideal, and the oil-cooled motor can operate at the peak torque.

[0128] S33, in response to the current oil temperature being greater than the first threshold temperature and less than or equal to the second threshold temperature, the first maximum torque is less than the peak torque and greater than or equal to the continuous torque.

[0129] Specifically, in response to the current oil temperature being greater than or equal to the first threshold temperature and less than the second threshold temperature, the first maximum torque is less than the peak torque and greater than or equal to the continuous torque.

[0130] It can be understood that the current oil temperature is greater than or equal to the first threshold temperature and less than or equal to the second threshold temperature, which means that the first type component has a certain temperature rise and cannot operate continuously under the peak torque condition, but can operate under the condition greater than or equal to the continuous torque.

[0131] S34, in response to the current oil temperature being greater than the second threshold temperature, the first maximum torque is less than the continuous torque.

[0132] Specifically, in response to the current oil temperature being greater than the second threshold temperature, the first maximum torque is less than the continuous torque.

[0133] It can be understood that the current oil temperature is greater than the second threshold temperature, which means that the temperature rise of the first type component is more serious and cannot continue to operate under continuous torque conditions. It is necessary to further limit the maximum torque to reduce the heat generation of the oil-cooled motor and ensure that the first type component does not operate overtemperature.

[0134] S35, obtaining the limited power coefficient of the oil-cooled motor, and determining the second maximum torque of the oil-cooled motor at the current speed by using the peak torque, the continuous torque and the limited power coefficient.

[0135] Among them, the oil-cooled motor can continue to operate safely at the second maximum torque.

[0136] S36, selecting the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current rotation speed.

[0137] The above scheme, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtains the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; obtains the power limit coefficient of the oil cooling motor, and uses the peak torque, continuous torque and power limit coefficient to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil-cooled motor provided in the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience.

[0138] Another embodiment of the method for determining the maximum torque of an oil-cooled motor provided by the present application may specifically include the following steps:

[0139] S41, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, the peak torque and continuous torque of the oil-cooled motor at the current speed are obtained according to the current water temperature of the water cooling circuit, and the first maximum torque corresponding to the oil-cooled motor at the current speed is determined according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque.

[0140] Among them, the oil-cooled motor is located in an oil cooling circuit, and the oil cooling circuit and the water cooling circuit perform heat exchange.

[0141] S42, determining an initial time coefficient by using the initial water temperature of the water cooling circuit, the initial oil temperature of the oil cooling circuit, and the initial temperature of the oil-cooling motor when the flow rate of the oil cooling circuit is less than the flow rate threshold.

[0142] Specifically, the torque determination device judges whether the oil-cooled motor is in a bad operating state based on the operating state of the oil-cooled motor when the flow rate of the oil cooling circuit is less than the flow threshold, such as the initial water temperature of the water cooling circuit, the initial oil temperature of the oil cooling circuit and the initial temperature of the oil-cooled motor, and selects the corresponding initial time coefficient β0 based on the above parameters.

[0143] S43, determining a power limit coefficient using the initial time coefficient.

[0144] Specifically, the power limit coefficient α is positively correlated with the initial time coefficient β0, and therefore, the power limit coefficient α can be determined by using the initial time coefficient β0.

[0145] S44, determining the second maximum torque of the oil-cooled motor at the current speed by using the peak torque, the continuous torque and the limited power factor.

[0146] Among them, the oil-cooled motor can continue to operate safely at the second maximum torque.

[0147] S45, selecting the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current rotation speed.

[0148] The above scheme, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtains the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; obtains the power limit coefficient of the oil cooling motor, and uses the peak torque, continuous torque and power limit coefficient to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil-cooled motor provided in the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience.

[0149] Another embodiment of the method for determining the maximum torque of an oil-cooled motor provided by the present application may specifically include the following steps:

[0150] S51, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, the peak torque and continuous torque of the oil-cooled motor at the current speed are obtained according to the current water temperature of the water cooling circuit, and the first maximum torque corresponding to the oil-cooled motor at the current speed is determined according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque.

[0151] Among them, the oil-cooled motor is located in an oil cooling circuit, and the oil cooling circuit and the water cooling circuit perform heat exchange.

[0152] S52, determining an initial time coefficient by using the initial water temperature of the water cooling circuit, the initial oil temperature of the oil cooling circuit, and the initial temperature of the oil-cooling motor when the flow rate of the oil cooling circuit is less than the flow rate threshold.

[0153] S53, obtaining a first operating time when the peak torque corresponds to no temperature rise risk, and obtaining a second operating time when the average of the peak torque and the continuous torque corresponds to no temperature rise risk.

[0154] Specifically, the torque determination device obtains the operating time of the oil-cooled motor without the risk of temperature rise under the working conditions of a certain speed and a peak torque corresponding to the speed, that is, the first operating time.

[0155] In some embodiments, the first operating time may be expressed as tz, and its corresponding peak torque is Tp.

[0156] Specifically, the torque determination device obtains the operating time of the oil-cooled motor without the risk of temperature rise under the condition of a certain speed and the average of the peak torque and the continuous torque corresponding to the speed, that is, the second operating time.

[0157] In some embodiments, the second operating time may be expressed as ty, and the corresponding average of the peak torque and the continuous torque may be expressed as (Tp+Tc) / 2.

[0158] It can be understood that at the same rotation speed, the first running time tz is shorter than the second running time ty.

[0159] S54, obtaining a third operating time for the oil-cooled motor to reach a constant temperature when the continuous torque is reduced from one-half of the continuous torque; and a fourth operating time for the oil-cooled motor to reach a constant temperature when the continuous torque is reduced from zero torque.

[0160] In some embodiments, the torque determination device obtains the third operating time required for the oil-cooled motor to reduce from a continuous torque to half the continuous torque at a certain speed, and the oil-cooled motor to reduce from a first steady-state temperature of the continuous torque to a second steady-state temperature under the current operating condition (unchanged speed and torque of half the continuous torque).

[0161] In some embodiments, the third operating time may be expressed as tx, and the corresponding half continuous torque may be expressed as Tc / 2.

[0162] In some embodiments, the torque determination device obtains the fourth operating time required for the oil-cooled motor to decrease from a continuous torque to zero torque at a certain speed, and the oil-cooled motor to decrease from a first steady-state temperature of continuous torque to a third steady-state temperature under the current operating condition (speed remains unchanged, torque is zero torque).

[0163] In some embodiments, the fourth running time may be represented as tw.

[0164] S55, obtaining a standard time coefficient using the first running time, the second running time, the third running time and the fourth running time.

[0165] Specifically, the torque determination device calculates the least common multiple among the first running time tz, the second running time ty, the third running time tx, and the fourth running time tw to obtain the standard time coefficient β 标 .

[0166] S56, determining a power limit coefficient using the initial time coefficient and the standard time coefficient.

[0167] In some embodiments, the power limit coefficient α, the initial time coefficient β0 and the standard time coefficient β 标 The ratio of is positively correlated. That is:

[0168]

[0169] S57, determining the second maximum torque of the oil-cooled motor at the current speed by using the peak torque, the continuous torque and the limited power factor.

[0170] Among them, the oil-cooled motor can continue to operate safely at the second maximum torque.

[0171] S58, selecting the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current rotation speed.

[0172] The above scheme, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtains the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; obtains the power limit coefficient of the oil cooling motor, and uses the peak torque, continuous torque and power limit coefficient to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil-cooled motor provided in the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience.

[0173] Another embodiment of the method for determining the maximum torque of an oil-cooled motor provided by the present application may specifically include the following steps:

[0174] S61, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtain the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determine the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque.

[0175] Among them, the oil-cooled motor is located in an oil cooling circuit, and the oil cooling circuit and the water cooling circuit perform heat exchange.

[0176] S62, determining an initial time coefficient by using the initial water temperature of the water cooling circuit, the initial oil temperature of the oil cooling circuit, and the initial temperature of the oil-cooling motor when the flow rate of the oil cooling circuit is less than the flow rate threshold.

[0177] S63, obtaining a first operating time when the peak torque corresponds to no temperature rise risk, and obtaining a second operating time when the average of the peak torque and the continuous torque corresponds to no temperature rise risk.

[0178] S64, obtaining a third operating time for the oil-cooled motor to reach a constant temperature when the continuous torque is reduced from one-half of the continuous torque; and a fourth operating time for the oil-cooled motor to reach a constant temperature when the continuous torque is reduced from zero torque.

[0179] S65, obtaining a standard time coefficient using the first running time, the second running time, the third running time and the fourth running time.

[0180] S66, using the peak torque to obtain the first time conversion coefficient; using the average of the peak torque and the continuous torque to obtain the second time conversion coefficient; using half of the continuous torque to obtain the third time conversion coefficient; using zero torque to obtain the fourth time conversion coefficient.

[0181] Specifically, the torque determination device uses the peak torque Tp corresponding to the current speed to obtain the first time conversion coefficient d; uses the average of the peak torque and the continuous torque (Tc+Tp) / 2 corresponding to the current speed to obtain the second time conversion coefficient c; uses half of the continuous torque Tc / 2 corresponding to the current speed to obtain the third time conversion coefficient -b; and uses the zero torque corresponding to the current speed to obtain the fourth time conversion coefficient -a.

[0182] In some embodiments, the four time conversion factors may be expressed as (-a, -b, c, d).

[0183] In some possible embodiments, the time conversion coefficient can use the speed and torque of the oil-cooled motor to query the time conversion coefficient under different working conditions from the operating condition time conversion coefficient table. For example, the operating condition time conversion coefficient table can be shown in the following table:

[0184]

[0185]

[0186] It should be noted that the operating condition refers to the operating condition of the oil-cooled motor at a certain speed and torque.

[0187] S67, obtaining an operating condition time coefficient using the first time conversion coefficient, the second time conversion coefficient, the third time conversion coefficient, the fourth time conversion coefficient and their respective corresponding actual operating times.

[0188] In some embodiments, the actual running time corresponding to the first time conversion coefficient d is t1, the actual running time corresponding to the second time conversion coefficient c is t2, the actual running time corresponding to the third time conversion coefficient -b is t3, and the actual running time corresponding to the fourth time conversion coefficient -a is t4.

[0189] Exemplarily, the operating condition time coefficient satisfies the following relationship:

[0190] β=d*t1+c*t2+(-b)*t3+(-a)*t4

[0191] Wherein, β is the operating condition time coefficient. In some embodiments, the minimum value of β is 0, and the maximum value of β is the standard time coefficient β 标 .

[0192] S68, determining a power limit coefficient using the initial time coefficient, the standard time coefficient, and the operating condition time coefficient.

[0193] Specifically, the torque determination device calculates the limited power coefficient using the initial time coefficient, the standard time coefficient and the operating condition time coefficient.

[0194] Exemplarily, the power limit coefficient satisfies the following relationship:

[0195]

[0196] Among them, β0 is the initial time coefficient, β is the operating condition time coefficient, and β 标 is the standard time coefficient, and α is the limited power coefficient.

[0197] S69: Determine the second maximum torque of the oil-cooled motor at the current speed by using the peak torque, the continuous torque and the limited power factor.

[0198] Among them, the oil-cooled motor can continue to operate safely at the second maximum torque.

[0199] S70: Select the smallest one of the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current rotation speed.

[0200] The above scheme, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtains the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; obtains the power limit coefficient of the oil cooling motor, and uses the peak torque, continuous torque and power limit coefficient to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil-cooled motor provided in the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience.

[0201] Another embodiment of the method for determining the maximum torque of an oil-cooled motor provided by the present application may specifically include the following steps:

[0202] S71, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtain the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determine the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque.

[0203] Among them, the oil-cooled motor is located in an oil cooling circuit, and the oil cooling circuit and the water cooling circuit perform heat exchange.

[0204] S72, obtaining a power limit coefficient of the oil-cooled motor, and determining a second maximum torque of the oil-cooled motor at a current speed by using the peak torque, the continuous torque, and the power limit coefficient.

[0205] Among them, the oil-cooled motor can continue to operate safely at the second maximum torque.

[0206] S73, obtaining the current motor temperature of the oil-cooled motor.

[0207] Specifically, the torque determination device obtains the temperature of the oil-cooled motor at the current moment, that is, the current motor temperature.

[0208] S74, in response to the current motor temperature exceeding the target temperature threshold, determining a third maximum torque according to the current rotation speed of the oil-cooled motor.

[0209] The target temperature threshold is obtained by lowering the default temperature threshold when the flow rate of the oil cooling circuit is greater than or equal to the flow rate threshold.

[0210] In some possible application scenarios, in response to the current motor temperature not exceeding the target temperature threshold, a third maximum torque is determined from a preset maximum torque-speed curve according to the current speed of the oil-cooled motor. The preset maximum torque-speed curve is a maximum torque-speed curve of the oil-cooled motor when the flow rate of the oil cooling circuit is greater than or equal to the flow rate threshold.

[0211] In some possible application scenarios, in response to the current motor temperature exceeding the target temperature threshold, the torque determination device determines the third maximum torque from the updated maximum torque-speed curve. It can be understood that when the motor speed remains unchanged, the torque determined from the preset maximum torque-speed curve is greater than the torque determined from the updated maximum torque-speed curve, and the maximum torque of the oil-cooled motor is lowered to reduce the heat generated by the oil-cooled motor, thereby achieving overheat protection for the oil-cooled motor.

[0212] Exemplarily, the default temperature threshold is 130°C, and the lowered default temperature threshold is 90°C. When the flow rate of the oil cooling circuit is greater than or equal to the flow rate threshold, the oil-cooled motor has normal heat dissipation capacity. When the current temperature of the oil-cooled motor is greater than 130°C, the torque determination device uses the updated maximum torque-speed curve to determine the maximum torque of the oil-cooled motor at the current speed, thereby achieving derating protection for the oil-cooled motor. When the flow rate of the oil cooling circuit is less than the flow rate threshold, the oil-cooled motor has insufficient heat dissipation capacity. If the temperature threshold of 130°C is still used, the oil-cooled motor may be difficult to effectively cool down at this temperature, and there is a problem of easy overheating. In this embodiment, the lowered default temperature threshold is used to limit the maximum torque of the oil-cooled motor, and the power limiting operation of the oil-cooled motor is performed as soon as possible to improve the operating reliability of the oil-cooled motor.

[0213] S75, selecting the smallest one among the first maximum torque, the second maximum torque, and the third maximum torque as the target maximum torque of the oil-cooled motor at the current rotation speed.

[0214] Specifically, the torque determination device selects the smallest one from the first maximum torque, the second maximum torque, and the third maximum torque as the target maximum torque of the oil-cooled motor at the current speed.

[0215] It can be understood that the smallest maximum torque determined from the above three different methods is selected as the target maximum torque to more accurately protect the oil-cooled motor from over-temperature.

[0216] The above scheme, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtains the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; obtains the power limit coefficient of the oil cooling motor, and uses the peak torque, continuous torque and power limit coefficient to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil-cooled motor provided in the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience.

[0217] An embodiment of a method for determining the maximum torque of an oil-cooled electric drive provided in the present application may specifically include the following steps:

[0218] S101, in response to an oil pump failure, an oil-cooled electric drive failure prompt is issued.

[0219] Specifically, in response to an oil pump failure, the torque determination device sends an oil-cooled electric drive failure prompt to the user, indicating that the output of the oil-cooled electric drive is limited.

[0220] In some embodiments, the oil-cooled electric drive may be an electric drive assembly of a vehicle (including a motor, a reducer, and a motor controller).

[0221] Exemplarily, the torque determination device uses the vehicle's dashboard to remind the driver that the vehicle's power is limited, the driver should pay attention to driving safety, and the vehicle needs maintenance and inspection.

[0222] S102, obtaining a motor temperature limit power curve corresponding to the current motor temperature, and using the motor temperature limit power curve to determine a first allowable maximum torque corresponding to the current speed.

[0223] Specifically, after the oil pump fails, the torque determination device performs a derating process according to the current temperature of the motor, which is similar to the derating process under normal working conditions, that is, using different temperature thresholds to limit the external characteristics of the motor, that is, lowering the power temperature threshold to obtain the motor temperature limit power curve at the current motor temperature. Further, the torque determination device determines the first maximum allowable torque T corresponding to the current speed from the motor temperature limit power curve according to the current speed of the oil-cooled electric drive. m .

[0224] Among them, the first maximum allowable torque T m Corresponding to the third maximum torque above.

[0225] In some embodiments, derating refers to reducing the maximum allowable torque of the oil-cooled electric drive.

[0226] It can be understood that the motor temperature refers to the temperature inside the motor, and the torque determination device can determine the temperature through a temperature sensor arranged inside the motor.

[0227] S103, obtaining a reference water temperature continuous power limit curve and a reference water temperature peak power limit curve, and determining a target water temperature continuous power limit curve and a target water temperature peak power limit curve corresponding to the current water temperature according to the current water temperature of the current water cooling circuit.

[0228] It should be noted that the target water temperature continuous power limit curve and the target water temperature peak power limit curve are both maximum torque-speed curves of the motor. In some embodiments, the maximum torque-speed curve belongs to the motor external characteristic curve.

[0229] After the oil pump fails, the oil-cooled electric drive dissipates heat naturally through the housing of the electric drive. The heat dissipation rate is strongly correlated to the ambient temperature. The lower the ambient temperature, the greater the heat dissipation rate. Generally speaking, relevant temperature sensors are generally not set outside the housing of the oil-cooled electric drive, that is, the oil-cooled electric drive generally does not directly collect the ambient temperature. It can be understood that since the water cooling circuit still absorbs the heat generated by the oil cooling circuit to a certain extent, the ambient temperature is generally lower than the cooling water temperature. In this embodiment, the torque determination device uses the water temperature to indirectly reflect the ambient temperature.

[0230] In some embodiments, the torque determination device obtains a specific reference water temperature H when the oil pump is not working by simulation or calibration. w-0 The continuous external characteristic curve and the peak external characteristic curve under the reference water temperature are obtained, that is, the reference water temperature continuous limited power curve and the reference water temperature peak limited power curve are obtained.

[0231] The continuous external characteristic curve of the motor refers to the external characteristic curve composed of torque that can achieve continuous operation at different speeds, under the premise of ensuring that the components of the electric drive assembly do not overheat. The peak external characteristic curve of the motor refers to the external characteristic curve composed of torque that can achieve short-term operation at different speeds, under the premise of ensuring that the components of the electric drive assembly do not overheat.

[0232]

[0233] In order to characterize the influence of different water temperatures on the continuous external characteristic curve and the peak external characteristic curve of the motor, the torque determination device obtains the water temperature coefficient k through simulation or calibration, and establishes the relationship between the water temperature coefficient k and the water temperature H w Relationship curve.

[0234] Furthermore, the continuous external characteristic curve of the motor for different water temperatures = reference water temperature H w-0 The motor continuous external characteristic curve × water temperature coefficient k. Characterization corresponding to H w At water temperature, the components of the electric drive assembly have no risk of temperature rise, and the motor speed n and continuous torque T can be operated sustainably. c In some embodiments, the motor continuous external characteristic curve may also be referred to as a water temperature continuous power limit curve. Thus, the torque determination device may determine a target water temperature continuous power limit curve corresponding to the current water temperature.

[0235]

[0236] Different water temperatures to motor peak external characteristic curve = reference water temperature H w-0 The motor peak external characteristic curve × water temperature coefficient k. Characterization corresponding to H w At water temperature, the motor speed n and peak torque T that can be operated for a short time without the risk of temperature rise of the components of the electric drive assembly p In some embodiments, the motor peak external characteristic curve may also be referred to as a water temperature peak power limiting curve.

[0237] Thus, the torque determination device can determine the target water temperature peak power limit curve corresponding to the current water temperature.

[0238]

[0239] S104, using the target water temperature continuous power limit curve and the target water temperature peak power limit curve, determine the continuous torque and peak torque corresponding to the current speed.

[0240] Specifically, the torque determination device determines the continuous torque from the target water temperature continuous power limit curve using the current speed, and determines the peak torque from the target water temperature peak power limit curve using the current speed.

[0241] In some embodiments, the target water temperature continuous power limiting curve and the target water temperature peak power limiting curve are both external characteristic curves.

[0242] S105, determining an oil temperature limit power curve corresponding to the current oil temperature according to the current oil temperature of the oil cooling circuit, as well as the continuous torque and the peak torque, and determining a second allowable maximum torque corresponding to the current speed using the oil temperature limit power curve.

[0243] Specifically, after the oil pump fails, some parts of the oil-cooled electric drive can be cooled by contact with the oil through the reducer stirring oil or the rotor throwing oil (such as the reducer gears), and the oil temperature can indirectly reflect the temperature rise of these parts. The torque determination device can use the oil temperature to limit the power output of the motor and protect these parts from overheating.

[0244] In some embodiments, the torque determination device establishes the oil temperature H o The second maximum permissible torque T o Assume that the oil temperature when the electric drive is not working and in cold state is H o-0 When the electric drive is running continuously, the corresponding oil temperature is H o-1 Among them, H o-0 Corresponding to the first threshold temperature above.

[0245] When the oil temperature H o ≤H o-0 When the second maximum allowable torque T o =kT p (peak torque). o-0 <H o ≤H o-1 When kT c (Continuous torque) ≤ the second maximum allowable torque T o <kT p When H o-1 Oil temperature H o When the second maximum allowable torque T oGradually limited to 0Nm.

[0246] Among them, H o-1 Corresponding to the second threshold temperature above.

[0247] The second allowable maximum torque corresponds to the first maximum torque mentioned above.

[0248] S106, obtaining an initial per-unit operating time coefficient when the oil pump fails, and obtaining an operating condition time coefficient.

[0249] It should be noted that after the oil pump fails, other components in the oil-cooled electric drive (such as the motor stator and bearings) can no longer come into contact with the oil and can only dissipate heat naturally. The oil temperature in the oil cooling circuit cannot effectively reflect the temperature rise of these components.

[0250] Specifically, when T c <Torque T≤T p When the torque determination device obtains the time that the electric drive can run without the risk of temperature rise under a certain working condition through simulation or calibration, for example, t z ,t y When 0≤TorqueT≤T c When the torque determination device obtains the time required for the internal temperature of the electric drive to drop from a high temperature with continuous torque to a low temperature with small torque through simulation or calibration, for example, denoted as t x ,t w .

[0251] Furthermore, the per-unit operating time coefficient β is set 标 According to the allowable operating time under each operating condition, the per unit operating condition time coefficient β 标 The following relations are satisfied:

[0252] β 标 =|d×t z |=|c×t y |=|-b×t x |=|-a×t w |

[0253] By using the above method, the operating time conversion coefficients (-a, -b, c, d) of the oil-cooled electric drive under different operating conditions after the oil pump fails can be obtained.

[0254] In some embodiments, the following table can be obtained:

[0255]

[0256] Furthermore, the torque determination device consults the trademark according to the motor speed n and the torque T, obtains the time conversion coefficient corresponding to different working conditions, and multiplies and adds the time conversion coefficient of each working condition of the electric drive after the oil pump failure and the corresponding time to obtain the operating condition time coefficient β, wherein the lower limit value of the operating condition time coefficient β is 0, and the upper limit value is β 标 .

[0257] In some embodiments, the operating condition time coefficient satisfies the following relationship:

[0258] β=(d1×t1+c2×t2+c2×t1+(-b3)×t3+…+(-a4)×t4)=∑(time conversion coefficient×t).

[0259] S107, using the initial per-unit operating time coefficient and the operating condition time coefficient, determine the operating condition limit power coefficient, and use the operating condition limit power coefficient to determine the operating condition limit power curve.

[0260] According to the moment of oil pump failure, the torque determination device determines whether the oil-cooled electric drive is in a worse operating state according to the operating state of the electric drive, such as the water temperature of the water cooling circuit, the oil temperature of the oil cooling circuit, the motor temperature and other conditions, and selects the corresponding initial per-unit operating time coefficient β0 according to the operating state of the oil-cooled electric drive, wherein the value of the initial per-unit operating time coefficient β0 is within (0, β 标 ) interval.

[0261] Furthermore, the operating condition power limit coefficient satisfies the following relationship:

[0262] α=(β0+β) / β 标

[0263] Among them, α is the operating condition limit power coefficient, and its lower limit value is 0 and the upper limit value is 1. The operating condition limit power coefficient is used to characterize the temperature rise under the comprehensive effect of the electric drive operating condition loss and heat dissipation after the oil pump fails.

[0264] In some embodiments, the maximum torque allowed by the motor at a certain speed satisfies the following relationship:

[0265] T t =kT c +(kT p -kT c )*(1-α)

[0266] Among them, T t is the maximum torque allowed by the motor. In some embodiments, T t Also known as the third allowable maximum torque.

[0267] Furthermore, the torque determination device constructs a power limit curve for operating conditions according to the maximum allowable torque of the motor corresponding to different speeds.

[0268] In some possible embodiments, the operating condition power limit curve may be predetermined through simulation or actual measurement.

[0269] S108: Determine a third allowable maximum torque corresponding to the current speed from the operating condition power limit curve.

[0270] Specifically, the torque determination device uses the current speed to obtain the third allowable maximum torque T from the operating condition limit power curve. t .

[0271] The third allowable maximum torque corresponds to the second maximum torque mentioned above.

[0272] Similarly, the operating condition power limit curve is also the maximum torque-speed curve.

[0273] S109: Select the smallest one among the first allowable maximum torque, the second allowable maximum torque, and the third allowable maximum torque as the allowable maximum torque at the current speed.

[0274] In some possible embodiments, the torque determination device forms a dynamic power limit curve after an oil pump failure according to different motor speeds and the maximum allowable torques at different speeds.

[0275] The above scheme, in response to the flow rate of the oil cooling circuit being less than the flow rate threshold, obtains the peak torque and continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit, and determines the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or continuous torque; obtains the power limit coefficient of the oil cooling motor, and uses the peak torque, continuous torque and power limit coefficient to determine the second maximum torque at which the oil cooling motor can continue to operate safely at the current speed; selects the smallest one from the first maximum torque and the second maximum torque as the target maximum torque of the oil cooling motor at the current speed. The maximum torque determination method of the oil-cooled motor provided in the present application more accurately and reasonably determines the maximum torque at which the oil cooling motor can continue to operate safely, and maximizes the performance of the oil cooling motor while ensuring the safe operation of the oil cooling motor, thereby improving the user experience.

[0276] In addition, the method for determining the maximum torque of the oil-cooled electric drive provided in this application can realize accurate over-temperature protection for the internal bearings, motor stators, rotors and other parts of the electric drive after the oil pump fails, by combining the water temperature, oil temperature, motor temperature and other signals with the operating conditions, thereby reducing the risk of damage and improving safety. On the premise of ensuring the safe operation of the electric drive components, the power is dynamically limited to fully release the performance of the electric drive, help the driver get out of trouble, and improve the user experience.

[0277] Please continue to see Figure 3 , Figure 3 The terminal device 500 of the embodiment of the present application includes a processor 51 and a memory 52 .

[0278] The processor 51 and the memory 52 are connected to the bus. The memory 52 stores program data. The processor 51 is used to execute the program data to implement the maximum torque determination method of the oil-cooled motor described in the above embodiment.

[0279] In the embodiment of the present application, the processor 51 may also be referred to as a CPU (Central Processing Unit). The processor 51 may be an integrated circuit chip having the ability to process signals. The processor 51 may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, or discrete hardware components. A general-purpose processor may be a microprocessor or the processor 51 may also be any conventional processor, etc.

[0280] This application also provides a computer storage medium, please continue to refer to Figure 4 , Figure 4 It is a structural diagram of an embodiment of a computer storage medium provided in the present application. The computer storage medium 600 stores program data 61. When the program data 61 is executed by the processor, it is used to implement the maximum torque determination method of the oil-cooled motor in the above embodiment.

[0281] When the embodiments of the present application are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk.

[0282] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Equivalent structures or equivalent process changes made by utilizing the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for determining the maximum torque of an oil-cooled motor, characterized in that: The oil-cooled motor is located in an oil-cooling circuit, and the oil-cooling circuit performs heat exchange with a water-cooling circuit. The method comprises: In response to the flow rate of the oil cooling circuit being less than a flow rate threshold, obtaining a peak torque and a continuous torque of the oil-cooled motor at a current speed according to a current water temperature of the water cooling circuit, and determining a first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit and the peak torque and / or the continuous torque; Obtaining a power limit coefficient of the oil-cooled motor, and determining a second maximum torque of the oil-cooled motor at the current speed by using the peak torque, the continuous torque and the power limit coefficient; wherein the oil-cooled motor can continue to operate safely at the second maximum torque; The smallest one of the first maximum torque and the second maximum torque is selected as the target maximum torque of the oil-cooled motor at the current rotation speed.

2. The method according to claim 1, characterized in that The step of obtaining the peak torque and the continuous torque of the oil-cooled motor at the current speed according to the current water temperature of the water cooling circuit includes: Obtaining a target continuous external characteristic curve and a target peak external characteristic curve of the oil-cooled motor at the current water temperature; The continuous torque is obtained from the target continuous external characteristic curve using the current rotation speed; and the peak torque is obtained from the target peak external characteristic curve.

3. The method according to claim 2, characterized in that The step of obtaining a target continuous external characteristic curve and a target peak external characteristic curve of the oil-cooled motor at the current water temperature includes: Obtaining a reference continuous external characteristic curve and a reference peak external characteristic curve of the oil-cooled motor at a reference water temperature; Determine a water temperature coefficient using the reference water temperature and the current water temperature; The target continuous external characteristic curve is obtained by using the water temperature coefficient and the reference continuous external characteristic curve; and the target peak external characteristic curve is obtained by using the water temperature coefficient and the reference peak external characteristic curve.

4. The method according to claim 1, characterized in that Determining the first maximum torque corresponding to the oil-cooled motor at the current speed according to the current oil temperature of the oil cooling circuit, and the peak torque and / or the continuous torque includes: In response to the current oil temperature being less than or equal to a first threshold temperature, taking the peak torque as the first maximum torque; In response to the current oil temperature being greater than the first threshold temperature and less than or equal to a second threshold temperature, the first maximum torque is less than the peak torque and greater than or equal to the continuous torque; In response to the current oil temperature being greater than the second threshold temperature, the first maximum torque is less than the continuous torque.

5. The method according to claim 1, characterized in that The obtaining of the limited power coefficient of the oil-cooled motor includes: Determine an initial time coefficient using the initial water temperature of the water cooling circuit, the initial oil temperature of the oil cooling circuit, and the initial temperature of the oil-cooling motor when the flow rate of the oil cooling circuit is less than the flow rate threshold; The power limit coefficient is determined using the initial time coefficient.

6. The method according to claim 5, characterized in that The determining the power limit coefficient by using the initial time coefficient includes: Acquire a first operating time when the peak torque corresponds to no temperature rise risk, and acquire a second operating time when the average of the peak torque and the continuous torque corresponds to no temperature rise risk; Obtaining a third operating time for the oil-cooled motor to reach a constant temperature when the continuous torque is reduced from the continuous torque to one-half of the continuous torque; and a fourth operating time for the oil-cooled motor to reach a constant temperature when the continuous torque is reduced from the continuous torque to zero torque; Obtaining a standard time coefficient using the first running time, the second running time, the third running time, and the fourth running time; The power limit coefficient is determined by using the initial time coefficient and the standard time coefficient.

7. The method according to claim 6, characterized in that The determining the power limit coefficient by using the initial time coefficient and the standard time coefficient includes: The peak torque is used to obtain a first time conversion coefficient; the average of the peak torque and the continuous torque is used to obtain a second time conversion coefficient; half of the continuous torque is used to obtain a third time conversion coefficient, and zero torque is used to obtain a fourth time conversion coefficient; Obtaining an operating condition time coefficient using the first time conversion coefficient, the second time conversion coefficient, the third time conversion coefficient, the fourth time conversion coefficient and their respective corresponding actual operating times; The power limit coefficient is determined by using the initial time coefficient, the standard time coefficient and the operating condition time coefficient.

8. The method according to claim 1, characterized in that Before the step of selecting the smallest one of the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current speed, the method includes: Obtaining the current motor temperature of the oil-cooled motor; In response to the current motor temperature exceeding a target temperature threshold, a third maximum torque is determined according to the current rotation speed of the oil-cooled motor; wherein the target temperature threshold is obtained by lowering a default temperature threshold when the flow rate of the oil cooling circuit is greater than or equal to the flow rate threshold; The selecting the smallest one of the first maximum torque and the second maximum torque as the target maximum torque of the oil-cooled motor at the current speed includes: A smallest one among the first maximum torque, the second maximum torque and the third maximum torque is selected as the target maximum torque of the oil-cooled motor at the current speed.

9. A terminal device, characterized in that: The terminal device includes a processor and a memory connected to the processor, wherein: The memory stores program instructions; The processor is configured to execute program instructions stored in the memory to implement the method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The storage medium stores program instructions, and when the program instructions are executed, the method according to any one of claims 1 to 8 is implemented.

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