Electric drive system liquid cooling control method, device, liquid cooling equipment and storage medium

Abstract

The present application provides a liquid cooling control method, device, liquid cooling equipment and storage medium for an electric drive system. The method includes: during the operation of the liquid cooling equipment, when the communication between the motor controller and the liquid pump controller is disconnected, obtaining the current working current and current speed of the liquid pump motor at a preset frequency; based on a first correspondence between the current and speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, determining the temperature corresponding to the current working current and the current speed as the first temperature of the coolant at the specified location; according to the first temperature and the preset control strategy, controlling the speed of the liquid pump motor so that the first temperature of the coolant at the specified location is less than a preset over-temperature threshold. In this way, after the motor controller loses control of the liquid pump motor, the liquid pump motor can still adaptively perform liquid cooling on the reducer housing and drive motor in the drive device, thereby improving the reliability of liquid cooling of the drive device.

Description

Technical Field

[0001] The present invention relates to the field of liquid cooling control technology, and in particular to a liquid cooling control method, device, liquid cooling equipment and storage medium for an electric drive system. Background Art

[0002] As people become more aware of energy shortages and environmental pollution, electric vehicles are rapidly gaining popularity and gradually taking over the automotive market. The drive equipment in an electric drive system includes the electric motor, motor controller, and transmission mechanism. Under the complex and ever-changing operating conditions of electric vehicles, the drive equipment generates a large amount of heat, requiring an effective cooling system to dissipate this heat in a timely manner to ensure the normal operation of the electric drive system.

[0003] Oil cooling is becoming increasingly popular as a cooling method for drive equipment. Cooling channels connect the reducer housing, motor rotor, motor housing, and motor bearings within the drive equipment. The motor controller sends a speed request to the oil pump, controlling its operation and driving the lubricating oil through the cooling channels, achieving direct cooling of the motor's internal structure.

[0004] During operation of the electric drive system, the communication line between the oil pump and the motor controller may become loose due to aging or vibration, resulting in loss of communication between the oil pump and the motor controller. Currently, when communication between the oil pump and the motor controller is lost, effective cooling control of the drive device is lost, which can easily cause the motor in the drive device to overheat, thus affecting the normal operation of the drive device. Summary of the Invention

[0005] In view of this, the purpose of the embodiments of the present application is to provide a liquid cooling control method, device, liquid cooling equipment and storage medium for an electric drive system, which can improve the problem that the drive equipment cannot be effectively cooled after the communication between the motor controller and the liquid pump motor is interrupted.

[0006] To achieve the above technical objectives, the technical solutions adopted in this application are as follows:

[0007] In a first aspect, an embodiment of the present application provides a liquid cooling control method for an electric drive system, which is applied to a liquid cooling device in the electric drive system. The electric drive system also includes a drive device, the drive device including a motor controller, a reducer housing, and a drive motor. The liquid cooling device includes a liquid pump motor, a liquid pump controller, and a cooling channel. The liquid pump motor is used to pump coolant through the cooling channel to cool the drive device. The method includes:

[0008] During the operation of the liquid cooling device, when the communication between the motor controller and the liquid pump controller is disconnected, obtaining the current operating current and the current speed of the liquid pump motor at a preset frequency;

[0009] Based on a pre-stored first correspondence between the current and the rotational speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, determining a temperature corresponding to the current operating current and the current rotational speed as a first temperature of the coolant at the specified location;

[0010] According to the first temperature and a preset control strategy, the rotation speed of the liquid pump motor is controlled so that the first temperature of the coolant at the designated location is less than a preset over-temperature threshold.

[0011] In combination with the first aspect, in some optional implementations, controlling the speed of the liquid pump motor according to the first temperature and a preset control strategy includes:

[0012] When the first temperature is greater than or equal to the preset over-temperature threshold, the liquid pump motor is controlled to operate at a maximum speed.

[0013] In combination with the first aspect, in some optional implementations, controlling the speed of the liquid pump motor according to the first temperature and a preset control strategy includes:

[0014] When the first temperature is greater than a preset safety threshold and less than or equal to the preset over-temperature threshold, the liquid pump motor is controlled to operate at a speed greater than 0 and less than a maximum speed.

[0015] In combination with the first aspect, in some optional implementations, controlling the liquid pump motor to operate at a speed greater than 0 and less than a maximum speed includes:

[0016] When the first temperature values ​​obtained two adjacent times are greater than the first temperature obtained earlier, the liquid pump motor is controlled to increase the speed of the liquid pump motor by a preset gradient and to operate, and the speed of the liquid pump motor after the increase is less than the maximum speed;

[0017] When the first temperature values ​​obtained two adjacent times are lower than the first temperature obtained earlier, the liquid pump motor is controlled to reduce the speed of the preset gradient and run, and the speed of the liquid pump motor after the reduction is greater than 0.

[0018] In combination with the first aspect, in some optional implementations, controlling the speed of the liquid pump motor according to the first temperature and a preset control strategy includes:

[0019] When the first temperature is less than or equal to a preset safety threshold, the liquid pump motor is controlled to stop running.

[0020] In combination with the first aspect, in some optional embodiments, the liquid pump motor further includes a temperature sensor for collecting the second temperature of the coolant at the designated location; and the method further includes:

[0021] When the difference between the second temperature and the first temperature is greater than a specified value, determining the speed corresponding to the second temperature as the target speed based on a pre-stored second correspondence between temperature and speed;

[0022] The liquid pump motor is controlled to operate at the target speed.

[0023] In combination with the first aspect, in some optional implementations, determining the speed corresponding to the second temperature as the target speed based on a pre-stored second correspondence between temperature and speed includes:

[0024] When the second temperature is greater than or equal to the preset over-temperature threshold, determining the maximum speed of the liquid pump motor as the target speed;

[0025] When the second temperature is greater than a preset safety threshold and less than or equal to a preset over-temperature threshold, searching the value table for a speed corresponding to the second temperature as the target speed;

[0026] When the second temperature is less than or equal to the preset safety threshold, the target speed is determined to be 0.

[0027] In a second aspect, an embodiment of the present application further provides a liquid cooling control device for an electric drive system, which is applied to a liquid cooling device in an electric drive system. The electric drive system further includes a drive device, the drive device including a motor controller, a reducer housing, and a drive motor. The liquid cooling device includes a liquid pump motor, a liquid pump controller, and a cooling channel. The liquid pump motor is used to pump coolant through the cooling channel to cool the drive device. The device includes:

[0028] an acquisition unit, configured to acquire a current operating current and a current rotational speed of the liquid pump motor at a preset frequency when the communication between the motor controller and the liquid pump controller is disconnected during the operation of the liquid cooling device;

[0029] a determining unit, configured to determine, based on a pre-stored first correspondence between the current and the rotational speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, a temperature corresponding to the current operating current and the current rotational speed, as a first temperature of the coolant at the specified location;

[0030] A control unit is used to control the rotation speed of the liquid pump motor according to the first temperature and a preset control strategy so that the first temperature of the coolant at the designated location is less than a preset over-temperature threshold.

[0031] In a third aspect, an embodiment of the present application further provides a liquid cooling device, which includes a liquid pump motor, a liquid pump controller, and a cooling channel. The liquid pump motor is used to pump coolant through the cooling channel to cool the driving device. A computer program is stored in the liquid pump controller. When the computer program is executed by the controller, the liquid cooling device performs the above method.

[0032] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium. When the computer program is run on a computer, the computer executes the above method.

[0033] The invention adopting the above technical solution has the following advantages:

[0034] In the technical solution provided in this application, during the operation of the liquid cooling device, when the communication between the motor controller and the liquid pump controller is disconnected, the current operating current and current speed of the liquid pump motor are obtained at a preset frequency; then, based on a pre-stored first correspondence between the current and speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, the temperature corresponding to the current operating current and current speed is determined as the first temperature of the coolant at the specified location; then, based on the first temperature and a preset control strategy, the speed of the liquid pump motor is controlled so that the first temperature of the coolant at the specified location is less than a preset overtemperature threshold. In this way, even after the motor controller loses control of the liquid pump motor, the liquid pump motor can still adaptively liquid-cool the reducer housing and drive motor in the drive device, thereby improving the reliability of liquid cooling of the drive device. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present application may be further illustrated by the non-limiting embodiments provided in the accompanying drawings. It should be understood that the following drawings illustrate only certain embodiments of the present application and are therefore not to be construed as limiting the scope of the present application. It is understood that a person skilled in the art can derive other relevant drawings from these drawings without inventive effort.

[0036] Figure 1 A block diagram of the electric drive system provided in an embodiment of the present application.

[0037] Figure 2 A flow chart of a liquid cooling control method for an electric drive system provided in an embodiment of the present application.

[0038] Figure 3 Schematic diagram of a numerical table showing the corresponding relationship between the speed, current and temperature of the liquid pump motor provided in an embodiment of the present application.

[0039] Figure 4 This is a block diagram of the liquid cooling control device for the electric drive system provided in an embodiment of the present application.

[0040] Icons: 20-liquid cooling device; 21-liquid pump controller; 22-liquid pump motor; 30-driving device; 31-motor controller; 32-driving motor; 200-liquid cooling control device; 210-acquisition unit; 220-determination unit; 230-control unit. DETAILED DESCRIPTION

[0041] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that similar or identical parts in the drawings or descriptions are numbered the same. Implementations not shown or described in the drawings are known to those of ordinary skill in the art. In the description of this application, the terms "first," "second," etc. are used solely to distinguish descriptions and are not to be construed as indicating or implying relative importance.

[0042] Please refer to Figure 1 An embodiment of the present application provides a liquid cooling device 20 including a liquid pump controller 21, a liquid pump motor 22 and a cooling channel. The liquid pump motor 22 is used to pump coolant through the cooling channel to cool the drive device 30. The liquid pump controller 21 stores a computer program. When the computer program is executed by the controller, the liquid cooling device 20 performs each step of the following electric drive system liquid cooling control method.

[0043] It is understandable that the liquid pump controller 21 is fixedly mounted on the liquid pump motor 22. The liquid inlet and the liquid outlet of the liquid pump motor 22 are connected to the cooling channel to form a cooling circuit.

[0044] The embodiment of the present application also provides an electric drive system. The electric drive system can be used in electric vehicles. Electric vehicles can use the electric drive system to convert electrical energy into mechanical energy and control the driving speed of the electric vehicle. The electric drive system may include a drive device 30 and the above-mentioned liquid cooling device 20. The drive device 30 includes a motor controller 31, a reducer housing and a drive motor 32. The cooling channel is connected to the reducer housing in the drive device 30, and is connected to the motor rotor, motor housing and motor bearings in the drive motor 32. The liquid pump motor 22 can achieve the purpose of cooling the drive motor 32, transmission mechanism (such as reducer housing) and other mechanisms in the drive device 30 by cyclically pumping coolant into the cooling channel.

[0045] The liquid pump motor 22 may be an oil pump motor. The coolant in the cooling channel may be lubricating oil, or other liquid suitable for cooling the drive device 30.

[0046] Typically, the motor controller 31 is electrically connected to the liquid pump controller 21 in the liquid cooling device 20 to ensure proper communication. The motor controller 31 can calculate the desired rotational speed of the liquid pump motor 22 based on the temperatures of the drive motor 32 and the transmission mechanism in the drive device 30. The motor controller 31 then transmits the calculated rotational speed to the liquid pump controller 21 via a control command, which controls the operation of the liquid pump motor 22 based on the calculated rotational speed. The calculation of the desired rotational speed of the liquid pump motor 22 by the motor controller 31 is conventional and will not be further described here.

[0047] When the communication between the motor controller 31 and the liquid pump controller 21 is interrupted, or due to other reasons, the liquid pump controller 21 cannot receive the control command of the liquid pump controller 21, the liquid cooling device 20 can adaptively cool the drive device 30 based on the following electric drive system liquid cooling control method to improve the reliability of cooling the drive device 30.

[0048] Please refer to Figure 2 The present application also provides a liquid cooling control method for an electric drive system, referred to as the liquid cooling control method. The liquid cooling control method can be applied to the above-mentioned electric drive system, with each step of the method being executed or implemented by the liquid cooling device 20.

[0049] The liquid cooling control method may include the following steps:

[0050] Step 110, during the operation of the liquid cooling device, when the communication between the motor controller and the liquid pump controller is disconnected, obtaining the current operating current and current speed of the liquid pump motor at a preset frequency;

[0051] Step 120: determining a temperature corresponding to the current operating current and the current speed based on a pre-stored first correspondence between the current and the speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, as a first temperature of the coolant at the specified location;

[0052] Step 130 : Control the rotation speed of the liquid pump motor according to the first temperature and a preset control strategy so that the first temperature of the coolant at the designated location is lower than a preset over-temperature threshold.

[0053] The following are the steps of the liquid cooling control method.

[0054] In step 110 , the liquid cooling device is in operation, which refers to a state after the liquid cooling device is powered on. At this time, the liquid pump motor may be in a standby state or a running state.

[0055] The method for detecting whether communication between the motor controller and the liquid pump controller is disconnected can be: during the operation of the liquid cooling device, if the liquid pump controller does not receive any control commands from the motor controller within a preset time period, then the communication is disconnected. The preset time period can be flexibly determined based on actual conditions. For example, the preset time period can be 10 seconds, 60 seconds, etc.

[0056] Generally speaking, when the communication between the motor controller and the liquid pump controller is normal, the motor controller will continuously send control commands to the liquid pump controller. Therefore, when the liquid pump controller does not receive any control commands from the motor controller within a preset time, it can be determined that the communication is disconnected.

[0057] The liquid pump controller can obtain the current operating current and current speed of the liquid pump motor at a preset frequency. The method for obtaining the operating current and speed is conventional and will not be described in detail here. The preset frequency can be flexibly determined based on actual conditions. For example, the preset frequency can be 1 time per second, 5 times per second, etc.

[0058] In step 120, the first corresponding relationship can be a pre-calibrated relationship table, which can be flexibly determined according to actual conditions. The inventors have found that in an electric drive system, when the liquid pump motor is running at a certain speed, the operating current of the liquid pump motor is related to the load of the liquid pump motor. When the coolant is lubricating oil, the load of the liquid pump motor is affected by the oil temperature. The higher the temperature of the driving device, the higher the oil temperature, the lower the viscosity of the lubricating oil, the smaller the resistance to the liquid pump motor at the same speed, and the corresponding load and current of the liquid pump motor are smaller. Conversely, the lower the temperature of the driving device, the lower the oil temperature, the greater the load and current of the liquid pump motor at the same speed. Among them, the oil temperature refers to the temperature of the coolant at a specified location in the cooling channel. The specified location can be a location in the cooling channel close to the liquid inlet of the liquid pump motor.

[0059] Through calibration test, we can get the numerical table of the correspondence between the current, speed and oil temperature of the liquid pump motor under the boundary conditions of normal operation (such as speed range, operating current range, operating temperature range, etc.). Figure 3 For example, in the header of the numerical table, the horizontal column header is the oil temperature value arranged from small to large, that is, from T min To T max The cells in the vertical table header are the speed values ​​arranged from small to large, from n min to n max The cell contents in the table are the operating current I of the liquid pump motor at the corresponding speed and oil temperature.

[0060] The liquid pump controller pre-stores this table of values. Therefore, in step 120, the liquid pump controller can look up the table to obtain the temperature corresponding to the current operating current and current speed. This temperature is the first temperature. The first temperature can be considered the oil temperature detected without using a temperature sensor.

[0061] If the numerical table does not contain a current value that is exactly the same as the current operating current, the current value closest to the current operating current is used as the indexed current value. Similarly, if the numerical table does not contain a speed value that is exactly the same as the current speed, the speed value closest to the current speed is used as the indexed speed value. Then, in the numerical table, the temperature corresponding to the indexed current value and speed value is recorded as the first temperature.

[0062] In step 130, both the preset control strategy and the preset over-temperature threshold can be flexibly set based on actual conditions to minimize overheating of the drive device. Understandably, if the first temperature of the coolant at a designated location is less than the preset over-temperature threshold, this generally indicates that the drive device is not overheating and is operating within an acceptable operating temperature range. As an optional embodiment, step 130 may include:

[0063] When the first temperature is greater than or equal to the preset over-temperature threshold, the liquid pump motor is controlled to operate at a maximum speed.

[0064] Understandably, if the first temperature is greater than or equal to the preset over-temperature threshold, it indicates that the drive device is in an over-temperature operating state. In this case, the liquid pump controller controls the liquid pump motor to operate at maximum speed, thereby providing liquid cooling to the drive device with maximum cooling efficiency, facilitating rapid cooling of the drive device, thereby quickly reducing the operating temperature of the drive device to an acceptable normal operating temperature range.

[0065] As an optional implementation, step 130 may include:

[0066] When the first temperature is greater than a preset safety threshold and less than or equal to the preset over-temperature threshold, the liquid pump motor is controlled to operate at a speed greater than 0 and less than a maximum speed.

[0067] Understandably, when the first temperature is greater than the preset safety threshold and less than or equal to the preset over-temperature threshold, it indicates that the drive device is operating within an acceptable temperature range, but the drive device still needs to be cooled. In this case, the liquid pump controller can control the liquid pump motor to operate at a speed less than the maximum speed.

[0068] For example, controlling the liquid pump motor to operate at a speed greater than 0 and less than a maximum speed includes:

[0069] When the first temperature values ​​obtained two adjacent times are greater than the first temperature obtained earlier, the liquid pump motor is controlled to increase the speed of the liquid pump motor by a preset gradient and to operate, and the speed of the liquid pump motor after the increase is less than the maximum speed;

[0070] When the first temperature values ​​obtained two adjacent times are lower than the first temperature obtained earlier, the liquid pump motor is controlled to reduce the speed of the preset gradient and run, and the speed of the liquid pump motor after the reduction is greater than 0.

[0071] Understandably, the liquid pump controller can calculate the first temperature of the liquid pump motor at different times based on the aforementioned numerical table, thereby detecting temperature changes. If a temperature increase is detected, that is, the later first temperature is greater than the earlier first temperature, the liquid pump controller can control the liquid pump motor to increase its speed by a preset gradient. The speed increase can be flexibly determined based on actual conditions. Furthermore, when the speed reaches a preset first speed, the speed increase is stopped. The first speed is a speed value slightly lower than the maximum speed.

[0072] Similarly, if the liquid pump controller detects a decrease in the first temperature, i.e., the first temperature after a time delay is lower than the first temperature before a time delay, the liquid pump controller can control the liquid pump motor to reduce its speed by a certain amount. The speed reduction can be flexibly determined based on actual conditions. Furthermore, the speed reduction stops when the speed drops to a preset second speed. The first speed is a speed value slightly greater than the minimum speed of the liquid pump motor.

[0073] As an optional implementation, step 130 may include:

[0074] When the first temperature is less than or equal to a preset safety threshold, the liquid pump motor is controlled to stop running.

[0075] Understandably, when the first temperature is less than or equal to the preset safety threshold, it means that the driving device can operate normally even without cooling. At this time, the liquid pump controller can control the liquid pump motor to stop running to achieve energy saving.

[0076] As an optional embodiment, the liquid pump motor may further include a temperature sensor for collecting the second temperature of the coolant at the designated location. The method may further include:

[0077] Step 140: When the difference between the second temperature and the first temperature is greater than a specified value, based on a pre-stored second correspondence between temperature and speed, determining the speed corresponding to the second temperature as the target speed;

[0078] Step 150: Control the liquid pump motor to operate at the target speed.

[0079] It is understandable that in step 140, the specified value can be flexibly set according to actual conditions. For example, the specified value can be a relatively small temperature value such as 1°C or 3°C. If the difference between the second temperature and the first temperature is greater than the specified value, it means that if the liquid pump controller continues to control the speed of the liquid pump motor based on the first temperature value, it is likely to cause a large control error, making the temperature of the drive device prone to abnormalities. If the difference between the second temperature and the first temperature is less than or equal to the specified value, it means that the liquid pump controller can continue to control the speed of the liquid pump motor based on the first temperature value without causing a large error.

[0080] The second correspondence can be a pre-calibrated numerical table. For ease of distinction, the numerical table for the first correspondence is referred to as the first numerical table, and the numerical table for the second correspondence is referred to as the second numerical table. Generally speaking, in the second numerical table, a higher second temperature indicates a higher actual temperature of the drive device, and therefore, a higher speed of the liquid pump motor is required to improve cooling efficiency.

[0081] The liquid pump controller may query the second value table for a rotational speed corresponding to a temperature that is the same as or closest to the current second temperature, and use the rotational speed as the target rotational speed.

[0082] The second correspondence is a pre-calibrated second numerical table of one-to-one correspondence between temperature and rotation speed. Step 140 may include:

[0083] When the second temperature is greater than or equal to the preset over-temperature threshold, determining the maximum speed of the liquid pump motor as the target speed;

[0084] When the second temperature is greater than a preset safety threshold and less than or equal to a preset over-temperature threshold, searching the value table for a speed corresponding to the second temperature as the target speed;

[0085] When the second temperature is less than or equal to the preset safety threshold, the target speed is determined to be 0.

[0086] Based on the above design, the liquid pump motor can automatically adjust its operating speed according to the calculated first temperature in the event of a loss of communication with the motor controller, thereby meeting the cooling requirements of the electric drive system. This also prevents the liquid pump motor from operating at a high speed even when the actual coolant temperature has dropped, which helps reduce the energy consumption of the liquid pump motor. Furthermore, when the difference between the first and second temperatures is large, the actual temperature sensed by the temperature sensor (i.e., the second temperature) can be used to correct the speed of the liquid pump motor, thereby improving the accuracy of liquid cooling control.

[0087] Please refer to Figure 4The present application also provides a liquid cooling control device for an electric drive system, referred to as liquid cooling control device 200. Liquid cooling control device 200 includes at least one software functional module that can be stored in a memory in the form of software or firmware or embedded in the operating system (OS) of the liquid cooling device. The processor is configured to execute executable modules stored in the memory, such as the software functional modules and computer programs included in liquid cooling control device 200.

[0088] The liquid cooling control device 200 includes an acquisition unit 210, a determination unit 220, and a control unit 230. The functions of each unit may be as follows:

[0089] an acquisition unit 210 for acquiring a current operating current and a current speed of the liquid pump motor at a preset frequency when the communication between the motor controller and the liquid pump controller is disconnected during the operation of the liquid cooling device;

[0090] a determining unit 220 configured to determine, based on a pre-stored first correspondence between the current and the rotational speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, a temperature corresponding to the current operating current and the current rotational speed as a first temperature of the coolant at the specified location;

[0091] The control unit 230 is configured to control the rotational speed of the liquid pump motor according to the first temperature and a preset control strategy so that the first temperature of the coolant at the designated location is less than a preset over-temperature threshold.

[0092] Optionally, the control unit 230 may be configured to: when the first temperature is greater than or equal to the preset over-temperature threshold, control the liquid pump motor to operate at a maximum speed.

[0093] Optionally, the control unit 230 may be configured to: when the first temperature is greater than a preset safety threshold and less than or equal to the preset over-temperature threshold, control the liquid pump motor to operate at a speed greater than 0 and less than a maximum speed.

[0094] Optionally, the control unit 230 can be used to: when two adjacent first temperature values ​​are obtained, if the first temperature at the later time is greater than the first temperature at the earlier time, control the liquid pump motor to increase the speed of the preset gradient and run, and the speed of the liquid pump motor after the increase is less than the maximum speed; when two adjacent first temperature values ​​are obtained, if the first temperature at the later time is less than the first temperature at the earlier time, control the liquid pump motor to reduce the speed of the preset gradient and run, and the speed of the liquid pump motor after the reduction is greater than 0.

[0095] Optionally, the control unit 230 may be configured to: when the first temperature is less than or equal to a preset safety threshold, control the liquid pump motor to stop running.

[0096] Optionally, the determination unit 220 may be further configured to: when the difference between the second temperature and the first temperature is greater than a specified value, determine, based on a pre-stored second correspondence between temperature and speed, a speed corresponding to the second temperature as the target speed. The control unit 230 may be configured to: control the liquid pump motor to operate at the target speed.

[0097] Optionally, the second corresponding relationship is a pre-calibrated second numerical table of one-to-one correspondence between temperature and rotation speed, and the determining unit 220 may further be configured to:

[0098] When the second temperature is greater than or equal to the preset over-temperature threshold, determining the maximum speed of the liquid pump motor as the target speed;

[0099] When the second temperature is greater than a preset safety threshold and less than or equal to a preset over-temperature threshold, searching the value table for a speed corresponding to the second temperature as the target speed;

[0100] When the second temperature is less than or equal to the preset safety threshold, the target speed is determined to be 0.

[0101] In this embodiment, the controller may include a processor and a memory. For example, the processor may be, but is not limited to, a microcontroller unit (MCU), a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components, and may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application.

[0102] The memory may be, but is not limited to, a random access memory, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, etc. In this embodiment, the memory may be used to store a first correspondence between the current and speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, a preset control strategy, a preset overtemperature threshold, a preset safety threshold, etc. Of course, the memory may also be used to store a program, which the processor executes upon receiving an execution instruction.

[0103] It is understandable that Figure 1 The electric drive system structure shown in FIG is only a structural diagram. The electric drive system may also include Figure 1 More components shown. Figure 1 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0104] It should be noted that those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working process of the electric drive system described above can refer to the corresponding processes of each step in the aforementioned method, and will not be elaborated here.

[0105] The present application also provides a computer-readable storage medium that stores a computer program, which, when executed on a computer, causes the computer to execute the liquid cooling control method described in the above embodiment.

[0106] Through the description of the above implementation methods, those skilled in the art can clearly understand that the present application can be implemented through hardware or by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each implementation scenario of the present application.

[0107] In summary, the embodiments of the present application provide a liquid cooling control method, device, liquid cooling equipment and storage medium for an electric drive system. In this solution, during the operation of the liquid cooling equipment, when the communication between the motor controller and the liquid pump controller is disconnected, the current working current and current speed of the liquid pump motor are obtained at a preset frequency; then, based on the pre-stored first correspondence between the current and speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, the temperature corresponding to the current working current and the current speed is determined as the first temperature of the coolant at the specified location; then, based on the first temperature and the preset control strategy, the speed of the liquid pump motor is controlled so that the first temperature of the coolant at the specified location is less than the preset over-temperature threshold. In this way, after the motor controller loses control of the liquid pump motor, the liquid pump motor can still adaptively perform liquid cooling on the reducer housing and drive motor and other equipment in the drive device, thereby helping to improve the reliability of liquid cooling of the drive device.

[0108] In the embodiments provided in the present application, it should be understood that the disclosed devices, systems and methods can also be implemented in other ways. The device, system and method embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to the multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of code, and a part of the module, program segment or code includes one or more executable instructions for implementing the specified logical function. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart can be implemented by a dedicated hardware-based system that performs the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions. In addition, the functional modules in the various embodiments of the present application can be integrated together to form an independent part, or each module can exist alone, or two or more modules can be integrated to form an independent part.

[0109] The above description is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, various modifications and variations of the present application are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A liquid cooling control method for an electric drive system, characterized in that: A liquid cooling device used in an electric drive system, the electric drive system also including a drive device, the drive device including a motor controller, a reducer housing, and a drive motor, the liquid cooling device including a liquid pump motor, a liquid pump controller, and a cooling channel, the liquid pump motor being used to pump coolant through the cooling channel to cool the drive device, the method comprising: During the operation of the liquid cooling device, when the communication between the motor controller and the liquid pump controller is disconnected, obtaining the current operating current and the current speed of the liquid pump motor at a preset frequency; Based on a pre-stored first correspondence between the current and the rotational speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, determining a temperature corresponding to the current operating current and the current rotational speed as a first temperature of the coolant at the specified location; According to the first temperature and a preset control strategy, controlling the speed of the liquid pump motor so that the first temperature of the coolant at the designated location is less than a preset over-temperature threshold; The liquid pump motor further includes a temperature sensor for collecting a second temperature of the coolant at the designated location; the method further includes: When the difference between the second temperature and the first temperature is greater than a specified value, determining the speed corresponding to the second temperature as the target speed based on a pre-stored second correspondence between temperature and speed; The liquid pump motor is controlled to operate at the target speed.

2. The method according to claim 1, characterized in that Controlling the speed of the liquid pump motor according to the first temperature and a preset control strategy includes: When the first temperature is greater than or equal to the preset over-temperature threshold, the liquid pump motor is controlled to operate at a maximum speed.

3. The method according to claim 1, characterized in that Controlling the speed of the liquid pump motor according to the first temperature and a preset control strategy includes: When the first temperature is greater than a preset safety threshold and less than or equal to the preset over-temperature threshold, the liquid pump motor is controlled to operate at a speed greater than 0 and less than a maximum speed.

4. The method according to claim 3, characterized in that Controlling the liquid pump motor to operate at a speed greater than 0 and less than a maximum speed includes: When the first temperature values ​​obtained two adjacent times are greater than the first temperature obtained earlier, the liquid pump motor is controlled to increase the speed of the liquid pump motor by a preset gradient and to operate, and the speed of the liquid pump motor after the increase is less than the maximum speed; When the first temperature values ​​obtained two adjacent times are lower than the first temperature obtained earlier, the liquid pump motor is controlled to reduce the speed of the preset gradient and run, and the speed of the liquid pump motor after the reduction is greater than 0.

5. The method according to claim 1, characterized in that Controlling the speed of the liquid pump motor according to the first temperature and a preset control strategy includes: When the first temperature is less than or equal to a preset safety threshold, the liquid pump motor is controlled to stop running.

6. The method according to claim 1, characterized in that The second correspondence is a pre-calibrated table of values ​​corresponding one-to-one between temperature and speed. Based on the pre-stored second correspondence between temperature and speed, determining the speed corresponding to the second temperature as the target speed includes: When the second temperature is greater than or equal to the preset over-temperature threshold, determining the maximum speed of the liquid pump motor as the target speed; When the second temperature is greater than a preset safety threshold and less than or equal to the preset over-temperature threshold, searching the value table for a speed corresponding to the second temperature as the target speed; When the second temperature is less than or equal to the preset safety threshold, the target speed is determined to be 0.

7. A liquid cooling control device for an electric drive system, characterized in that: A liquid cooling device used in an electric drive system, wherein the electric drive system also includes a drive device, the drive device includes a motor controller, a reducer housing, and a drive motor, the liquid cooling device includes a liquid pump motor, a liquid pump controller, and a cooling channel, the liquid pump motor is used to pump coolant through the cooling channel to cool the drive device, and the device includes: an acquisition unit, configured to acquire a current operating current and a current rotational speed of the liquid pump motor at a preset frequency when the communication between the motor controller and the liquid pump controller is disconnected during the operation of the liquid cooling device; a determining unit, configured to determine, based on a pre-stored first correspondence between the current and the rotational speed of the liquid pump motor and the temperature of the coolant at a specified location in the cooling channel, a temperature corresponding to the current operating current and the current rotational speed, as a first temperature of the coolant at the specified location; a control unit, configured to control the rotational speed of the liquid pump motor according to the first temperature and a preset control strategy, so that the first temperature of the coolant at the designated location is less than a preset over-temperature threshold; The liquid pump motor further includes a temperature sensor for collecting a second temperature of the coolant at the designated location; the determining unit is further configured to, when a difference between the second temperature and the first temperature is greater than a designated value, determine, based on a pre-stored second correspondence between temperature and speed, a speed corresponding to the second temperature as the target speed; The control unit is further configured to control the liquid pump motor to operate at the target speed.

8. A liquid cooling device, characterized in that: The liquid cooling device includes a liquid pump motor, a liquid pump controller and a cooling channel. The liquid pump motor is used to pump coolant through the cooling channel to cool the drive device. The liquid pump controller stores a computer program. When the computer program is executed by the controller, the liquid cooling device performs the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is run on a computer, the computer is caused to execute the method according to any one of claims 1 to 6.

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