An electric vehicle thermal management system fan control method, device and storage medium

Abstract

The application provides a fan control method, device and storage medium of an electric vehicle thermal management system. The method comprises the following steps: determining a wind volume compensation amount of the vehicle thermal management system according to a current running state of the vehicle; determining a target wind volume demand amount of the thermal management system according to the wind volume compensation amount, an electric drive wind volume demand amount and a fault diagnosis wind volume; converting the target wind volume demand amount into a fan pulse width modulation (PWM) signal, and discretely processing the fan PWM signal according to a duty cycle into multiple gears, each gear corresponding to a different fan rotating speed; and controlling the rotating speed of the fan according to the gear corresponding to the discretely processed PWM signal. The method of the application increases the performance of the vehicle, saves energy and reduces emissions, and improves the reliability of the function of the electric vehicle thermal management system.

Description

Technical Field

[0001] This application relates to the field of automotive technology, and in particular to a fan control method, device and storage medium for an electric vehicle thermal management system. Background Technology

[0002] The electrification, intelligentization, and integration of automotive thermal management systems represent current trends in automotive development. As a key component of the thermal management system, the cooling fan precisely and intelligently controls the airflow within the cabin, and its rotational speed directly affects the cooling airflow required for heat dissipation.

[0003] Currently, in automotive thermal management systems, the cooling fan speed is adjusted by changing the driving force.

[0004] Adjusting the cooling fan speed by changing the driving force results in low noise, vibration, and acoustic roughness performance, which can cause vibration and abnormal noise, waste resources, and reduce functional reliability, thereby affecting the overall vehicle performance and driving comfort. Summary of the Invention

[0005] This application provides a fan control method, device, and storage medium for an electric vehicle thermal management system, which solves the problem of controlling different fan speeds in different modes.

[0006] In a first aspect, this application provides a fan control method for an electric vehicle thermal management system, comprising:

[0007] Determine the airflow compensation amount of the vehicle's thermal management system based on the vehicle's current operating status.

[0008] The target air volume requirement of the thermal management system is determined based on the air volume compensation amount, the electric drive air volume requirement, and the fault diagnosis air volume.

[0009] The target air volume requirement is converted into a fan pulse width modulation (PWM) signal, and the fan PWM signal is discretized into multiple speeds according to the duty cycle, with each speed corresponding to a different fan speed.

[0010] The fan speed is controlled based on the gear corresponding to the discrete PWM signal.

[0011] Secondly, this application provides a fan control device for an electric vehicle thermal management system, comprising:

[0012] The acquisition module is used to determine the airflow compensation amount of the vehicle thermal management system based on the vehicle's current operating status.

[0013] The determination module is used to determine the target air volume requirement of the thermal management system based on the air volume compensation mode, the electric drive air volume requirement, and the fault diagnosis air volume.

[0014] The control module is used to convert the target air volume demand into a fan pulse width modulation (PWM) signal, and to discretize the fan PWM signal into multiple speed levels according to the duty cycle, with each speed level corresponding to a different fan speed; and to control the fan speed according to the speed level corresponding to the discretized PWM signal.

[0015] Thirdly, this application provides a fan control device for an electric vehicle thermal management system, including: a processor, and a memory communicatively connected to the processor;

[0016] The memory stores computer-executed instructions;

[0017] The processor executes computer execution instructions stored in the memory to implement the electric vehicle thermal management system fan control method as described in any of the preceding claims.

[0018] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the fan control method of the electric vehicle thermal management system as described in any of the preceding claims.

[0019] This application provides a fan control method, device, and storage medium for an electric vehicle thermal management system. Based on the vehicle's current operating state, it selects the corresponding mode's airflow compensation calculation logic to obtain the airflow compensation amount. Then, it combines the airflow compensation amount with the electric drive airflow demand and the fault diagnosis airflow to determine the target airflow demand of the thermal management system. By converting the target airflow demand into a PWM signal and discretizing the PWM signal into multiple duty cycle levels, the fan speed is controlled. Because the PWM signal converted from the target airflow demand is discretized into multiple levels, the fan can adjust according to the discretized levels. Therefore, the fan can sensitively and promptly adjust the airflow according to the airflow demand, thereby avoiding resource waste, saving energy and reducing emissions, and increasing the reliability of the electric vehicle thermal management system. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0021] Figure 1 A flowchart of an embodiment of the fan control method for an electric vehicle thermal management system provided in this application;

[0022] Figure 2 A flowchart illustrating an embodiment of the fan control method for an electric vehicle thermal management system provided in this application for obtaining airflow compensation.

[0023] Figure 3A flowchart illustrating an embodiment of the fan control method for an electric vehicle thermal management system provided in this application for obtaining target airflow requirements;

[0024] Figure 4 A flowchart illustrating an embodiment of the compressor pre-start of the fan control method for the electric vehicle thermal management system provided in this application;

[0025] Figure 5 A complete embodiment flowchart of the fan control method for the electric vehicle thermal management system provided in this application;

[0026] Figure 6 This is a schematic diagram of the fan control device for the electric vehicle thermal management system provided in an embodiment of this application;

[0027] Figure 7 This is a schematic diagram of a fan control device for an electric vehicle thermal management system provided in an embodiment of this application.

[0028] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0029] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0030] First, let me explain the terms used in this application:

[0031] PID control: where P stands for proportional, I for integral, and D for derivative. When there is a deviation in the process itself, the output of the PID module will change continuously, and the output will change in the direction of reducing the deviation (this is for negative feedback control systems).

[0032] NVH performance refers to noise, vibration, and acoustic roughness. NVH performance is a comprehensive issue that measures the quality of automobile manufacturing, and it provides the most direct and superficial experience to car users.

[0033] PWM: Pulse Width Modulation is an abbreviation for pulse width modulation. It modulates the width of a series of pulses to produce the desired waveform (including shape and amplitude), and digitally encodes the analog signal level. In other words, it regulates the changes in signal, energy, etc. by adjusting the duty cycle.

[0034] Duty cycle: refers to the percentage of time a signal is at a high level within a given period.

[0035] Heat pump operation: refers to the use of a compressor to absorb low-temperature heat energy from environmental heat sources (such as water or air) by consuming a certain amount of auxiliary energy (such as electrical energy) and under the combined action of the compressor and the refrigerant circulating in the heat exchange system. The heat energy is then converted into higher-temperature heat energy and released into the circulating medium (such as water or air) as a higher-temperature heat source output.

[0036] Non-heat pump operation: refers to the use of a compressor to obtain high-temperature and high-pressure gas by consuming a certain amount of auxiliary energy (such as electrical energy). After being cooled by an external condenser, the gas becomes a foamy gas-liquid mixture. Then, after being expanded by an electronic expansion valve, it becomes a low-temperature and low-pressure liquid refrigerant, which is then output as a low-temperature product.

[0037] High-pressure side: The section between the output of the air conditioner compressor and the input of the condenser is the high-pressure side of the air conditioning circulation system;

[0038] Low-pressure side: The section between the output of the air conditioner evaporator and the input of the compressor is the low-pressure side of the air conditioning circulation system.

[0039] In existing technologies, fan thermal management systems only adjust fan speed by changing the fan's driving force. This results in poor NVH performance, vibration and abnormal noise, waste of resources, and reduced passenger comfort. The electric vehicle thermal management system fan control method provided in this application determines the required target airflow by considering airflow compensation, electric drive airflow demand, and fault diagnosis airflow. The target airflow is converted into a PWM signal, which is then discretized into several speed levels based on its duty cycle. Each speed level corresponds to a different rotation speed. The fan speed is controlled according to the speed level corresponding to the discretized PWM signal. Therefore, the fan can sensitively and promptly adjust to airflow demand, avoiding resource waste, saving energy and reducing emissions, and increasing the reliability of the electric vehicle thermal management system.

[0040] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0041] Figure 1 A flowchart of an embodiment of the fan control method for the electric vehicle thermal management system provided in this application is shown below. Figure 1 As shown, the execution subject of this method is a control device installed inside the vehicle. This device can perform the following steps through hardware, software, or a combination of hardware and software. The method includes:

[0042] S101. Determine the airflow compensation amount of the vehicle thermal management system based on the current operating status of the vehicle.

[0043] When the vehicle is running, the current airflow compensation mode is determined and output. Based on this mode information, the corresponding airflow compensation calculation logic is selected, and the airflow compensation amount is output. For example, the current airflow compensation mode can be either heat pump operating mode or non-heat pump operating mode. In heat pump operating mode, the airflow compensation amount is obtained by calculating the pressure difference between the target pressure and the actual pressure on the low-pressure side of the heat pump, and then using PID control based on this pressure difference. In non-heat pump operating mode, the airflow compensation amount is obtained by calculating the pressure difference between the target pressure and the actual pressure on the high-pressure side of the non-heat pump, and then using PID control based on this pressure difference.

[0044] S102. Determine the target air volume requirement of the thermal management system based on the air volume compensation amount, the air volume requirement of electric drive and the air volume for fault diagnosis.

[0045] The target air volume requirement refers to the amount of air volume required to achieve the target air volume in the vehicle thermal management system, including: air volume compensation, electric drive air volume requirement, and fault diagnosis air volume.

[0046] Among them, the air volume requirement for electric drive is the air volume required to cool the vehicle motor.

[0047] Among them, the fault diagnosis air volume is the air volume required when a vehicle component malfunctions.

[0048] Therefore, to achieve the target airflow in a vehicle thermal management system, it is necessary to comprehensively consider the airflow compensation, the airflow required for motor cooling, and the airflow required in case of a malfunction.

[0049] S103. Convert the target air volume demand into a fan pulse width modulation (PWM) signal, and discretize the fan PWM signal into multiple speed levels according to the duty cycle, with each speed level corresponding to a different fan speed.

[0050] The target airflow demand is converted into a PWM signal. The fan PWM signal is then filtered, and the duty cycle of the fan PWM signal is discretized into multiple levels, such as 10 levels. Under different heat dissipation and heat absorption requirements, an appropriate duty cycle is output to control the fan speed.

[0051] S104. Control the fan speed according to the gear corresponding to the discrete PWM signal.

[0052] When the target air volume requirement is different, different fan speed settings need to be selected to control the fan speed.

[0053] Generally speaking, the PWM wave has the lowest duty cycle when the fan is off, usually around 7%. When the PWM wave has the highest duty cycle, such as 90%, the fan activates its maximum speed. Therefore, multiple different speed settings can be corresponding to different duty cycles between the two, and the corresponding fan speed can be selected according to the discrete speed settings.

[0054] The electric vehicle thermal management system fan control method provided in this application selects the corresponding mode's airflow compensation calculation logic based on the vehicle's current operating state to obtain the airflow compensation amount. This compensation amount, along with the electric drive airflow demand and fault diagnosis airflow, is then combined and output to determine the target airflow demand of the thermal management system. By converting the target airflow demand into a PWM signal and discretizing the PWM signal into multiple duty cycle levels, the fan speed is controlled. Because the PWM signal converted from the target airflow demand is discretized into multiple levels, the fan speed can be adjusted according to the discretized levels. Therefore, the fan can sensitively and promptly adjust the airflow according to the airflow demand, thereby avoiding resource waste, saving energy and reducing emissions, and increasing the reliability of the electric vehicle thermal management system.

[0055] like Figure 2 The diagram shown is a flowchart of an embodiment of the fan control method for an electric vehicle thermal management system provided in this application for obtaining airflow compensation. Figure 2 As shown, the method includes:

[0056] S201. Determine the current air volume compensation mode, and determine the first air volume compensation amount on the low-pressure side of the heat pump operation or the second air volume compensation amount on the high-pressure side of the non-heat pump operation according to the air volume compensation mode.

[0057] Step S201 provides a specific method for obtaining the air volume compensation amount based on the preceding step S101:

[0058] The airflow compensation mode can be, for example: mode switching / mode error, heat pump operating mode, or non-heat pump operating mode. The amount of airflow compensation varies depending on the mode.

[0059] If the air volume compensation mode is a heat pump operating mode, then execute S202; if the air volume compensation mode is a non-heat pump operating mode, then execute S203; if the air volume compensation mode is switching modes / mode error, then execute S204.

[0060] S202. Determine the first airflow compensation amount on the low-pressure side of the heat pump operation according to the airflow compensation mode, including:

[0061] The airflow compensation control on the low-pressure side of the heat pump is performed by calculating the pressure difference between the target pressure and the actual pressure on the low-pressure side of the heat pump; and obtaining the first airflow compensation amount by PID regulation based on the pressure difference.

[0062] S203. Determine the second airflow compensation amount on the high-pressure side of the non-heat pump operation according to the airflow compensation mode, including:

[0063] For non-heat pump operation, the high-pressure side airflow compensation control calculates the pressure difference between the target pressure and the actual pressure on the high-pressure side; based on the pressure difference, PID regulation is performed to obtain the second airflow compensation amount.

[0064] S204, Output fault status.

[0065] S205. Determine the air volume compensation amount of the vehicle thermal management system based on the first air volume compensation amount or the second air volume compensation amount.

[0066] In the corresponding airflow compensation mode, the first airflow compensation amount or the second airflow compensation amount is output as the airflow compensation amount of the vehicle thermal management system through the airflow compensation control on the low-pressure side of the heat pump operation or the airflow compensation control on the high-pressure side of the non-heat pump operation.

[0067] like Figure 3 The diagram shown is a flowchart of an embodiment of the fan control method for an electric vehicle thermal management system provided in this application for obtaining the target airflow requirement. Figure 3 As shown, the method includes:

[0068] S301. Determine the first air volume compensation amount on the low-pressure side of the heat pump operation or the second air volume compensation amount on the high-pressure side of the non-heat pump operation according to the air volume compensation mode, and obtain the air volume compensation amount.

[0069] If the airflow compensation mode is in mode switching / mode error, a fault status will be output. When the airflow compensation mode is heat pump operation mode or non-heat pump operation mode, the airflow compensation amount will be output.

[0070] S302. Based on the air volume required for cooling the vehicle's motor, the required air volume for electric drive is obtained.

[0071] Electric drive air volume requirement refers to the amount of air needed to cool the vehicle's motor.

[0072] S303. Obtain the fault diagnosis air volume based on the air volume required for vehicle component fault diagnosis.

[0073] Fault diagnosis airflow refers to the airflow required for fault diagnosis when a component inside a vehicle malfunctions.

[0074] S304, combined outputs S301, S302, and S303, yield the target air volume requirement of the thermal management system.

[0075] like Figure 4 The diagram shown is a flowchart of an embodiment of the compressor pre-start method of the fan control method for the electric vehicle thermal management system provided in this application. Figure 4 As shown, the method includes:

[0076] S401. Before determining the airflow compensation amount of the vehicle thermal management system, does it receive a compressor start signal? If yes, then execute S402.

[0077] S402. Determine whether the fan airflow is lower than the set threshold or the fan is not activated. If yes, execute S403; otherwise, execute S404.

[0078] S403: Delay the start of the compressor and send a start request to the fan; after the fan is turned on, start the compressor.

[0079] S404, the compressor is running normally.

[0080] In existing technologies, if the compressor in a vehicle's thermal management system starts up and then the fan starts up, the compressor will continue to operate, causing excessively high pressure on the high-pressure side and ultimately leading to compressor shutdown. In this application, the compressor requests the fan to start. After various checks, the compressor decides to start. If the fan airflow is below a threshold or the cooling fan is not activated, the compressor starts with a delay. The compressor's delay time is determined based on the system's high-pressure side pressure. When the compressor starts with a delay, it sends an activation request to the fan module to ensure normal compressor operation.

[0081] like Figure 5 The diagram shown is a complete embodiment flowchart of the fan control method for an electric vehicle thermal management system provided in this application. Figure 5 As shown, the method includes:

[0082] S501: Based on the autonomous heat pump air volume compensation control, output the air volume of the current mode, heat pump mode, and non-heat pump mode.

[0083] The autonomous heat pump air volume compensation control includes the following S502, S503, and S504.

[0084] S502, Airflow compensation mode selection.

[0085] The air volume compensation modes include: mode switching / mode error, heat pump working mode, and non-heat pump working mode.

[0086] S503, Low-pressure side airflow compensation control for heat pump operation.

[0087] The airflow compensation control on the low-pressure side of the heat pump is implemented by calculating the pressure difference between the target pressure and the actual pressure on the low-pressure side of the heat pump; PID regulation control is then performed based on the pressure difference.

[0088] S504, High-pressure side airflow compensation control for non-heat pump operation.

[0089] For non-heat pump operation, the high-pressure side airflow compensation control calculates the pressure difference between the target pressure and the actual pressure on the high-pressure side; and performs PID regulation control based on the pressure difference.

[0090] S505 combines status signals and airflow compensation output.

[0091] Status signals and air volume compensation output are combined: fault status judgment and air volume compensation output.

[0092] The status signal refers to the output of a fault status if the air volume compensation mode is in mode switching / mode error.

[0093] S506, Obtain the target air volume requirement.

[0094] The target air volume requirement includes: air volume compensation, electric drive air volume requirement, and fault diagnosis air volume.

[0095] S507 converts the target airflow demand into a fan PWM signal.

[0096] The target air volume demand is subtracted from the actual air volume output by the fan to obtain the air volume error. The air volume error is converted into a PWM signal to obtain the fan PWM wave increment. The fan PWM wave increment is added to the fan PWM signal of the previous fan control cycle to obtain the actual output PWM signal.

[0097] S508 filters the fan PWM signal.

[0098] S509, Fan target control output, controls the fan speed.

[0099] The fan target control output mainly controls the fan speed by controlling the fan power, sending a PWM signal request to the fan, and limiting the extreme values ​​of the fan PWM signal.

[0100] One possible embodiment of this application provides a fan control device for an electric vehicle thermal management system. Figure 6This is a schematic diagram of the fan control device for the electric vehicle thermal management system provided in an embodiment of this application, as shown below. Figure 6 As shown, the fan control device 60 of the electric vehicle thermal management system includes: an acquisition module 601, a determination module 602, and a control module 603;

[0101] The acquisition module 601 is used to determine the air volume compensation amount of the vehicle thermal management system based on the current operating status of the vehicle.

[0102] The determination module 602 is used to determine the target air volume requirement of the thermal management system based on the air volume compensation mode, the air volume requirement of electric drive, and the air volume for fault diagnosis.

[0103] The control module 603 is used to convert the target air volume demand into a fan pulse width modulation (PWM) signal, and to discretize the fan PWM signal into multiple speed levels according to the duty cycle, with each speed level corresponding to a different fan speed; and to control the fan speed according to the speed level corresponding to the discretized PWM signal.

[0104] One possible embodiment of this application provides a fan control device for an electric vehicle thermal management system. Figure 7 This is a schematic diagram of a fan control device for an electric vehicle thermal management system provided in an embodiment of this application, as shown below. Figure 7 As shown, the electric vehicle thermal management system fan control device 70 includes: processor 701, memory 702, and communication interface 703. The processor 701, memory 702, and communication interface 703 are connected via bus 704.

[0105] The memory 702 is used to store computer-executed instructions.

[0106] The processor 701 is used to execute computer execution instructions stored in the memory 702 to implement the above-mentioned vehicle anti-fogging control method.

[0107] The specific implementation process of processor 701 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0108] In the above Figure 7In the illustrated embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0109] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0110] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0111] In one possible embodiment of this application, a readable storage medium is also provided, on which computer-executable instructions are stored; the computer-executable instructions are used to implement the above-described electric vehicle thermal management system fan control method.

[0112] The aforementioned computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0113] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0114] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0115] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0116] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0117] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0118] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0119] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0120] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A fan control method for an electric vehicle thermal management system, characterized in that, include: Based on the vehicle's current operating status, determine the current airflow compensation mode, which includes heat pump operating mode and non-heat pump operating mode. If the current airflow compensation mode is heat pump operating mode, then calculate the pressure difference between the target pressure on the low-pressure side of the heat pump operating mode and the actual pressure on the low-pressure side of the heat pump operating mode. The first air volume compensation amount is obtained by PID regulation based on the pressure difference; If the current air volume compensation mode is a non-heat pump working mode, calculate the pressure difference between the target pressure on the high-pressure side of the non-heat pump working mode and the actual pressure on the high-pressure side of the non-heat pump working mode. The second air volume compensation amount is obtained by PID regulation based on the pressure difference; The first air volume compensation amount or the second air volume compensation amount is used as the air volume compensation amount of the vehicle thermal management system. The target air volume requirement of the thermal management system is determined based on the air volume compensation amount, the electric drive air volume requirement, and the fault diagnosis air volume. The target air volume requirement is converted into a fan pulse width modulation (PWM) signal, and the fan PWM signal is discretized into multiple speeds according to the duty cycle, with each speed corresponding to a different fan speed. The fan speed is controlled based on the gear corresponding to the discrete PWM signal.

2. The method according to claim 1, characterized in that, The method further includes: The first air volume compensation amount on the low-pressure side of the heat pump operating mode or the second air volume compensation amount on the high-pressure side of the non-heat pump operating mode is determined according to the air volume compensation mode to obtain the air volume compensation amount. The required air volume for electric drive is obtained based on the air volume required to cool down the vehicle's motor. The fault diagnosis airflow is obtained based on the airflow required for the fault diagnosis of the vehicle components.

3. The method according to any one of claims 1-2, characterized in that, Determining the target air volume requirement of the thermal management system includes: The target air volume requirement of the thermal management system is obtained by combining and superimposing the air volume compensation amount, the air volume requirement of the electric drive, and the air volume required for fault diagnosis.

4. The method according to claim 1, characterized in that, Before determining the airflow compensation amount of the vehicle thermal management system, the method further includes: If the compressor starts, and the fan's airflow is below a set threshold or the fan is not activated, the compressor is controlled to start with a delay. After the fan is turned on, the compressor is started.

5. A fan control device for an electric vehicle thermal management system, comprising: The acquisition module is used to determine the airflow compensation amount of the vehicle thermal management system based on the vehicle's current operating status. The determination module is used to determine the target air volume requirement of the thermal management system based on the air volume compensation mode, the electric drive air volume requirement, and the fault diagnosis air volume. The control module is used to convert the target air volume demand into a fan pulse width modulation (PWM) signal, and to discretize the fan PWM signal into multiple speed levels according to the duty cycle, with each speed level corresponding to a different fan speed; and to control the fan speed according to the speed level corresponding to the discretized PWM signal. The acquisition module is specifically used to determine the current air volume compensation mode, which includes heat pump operating mode and non-heat pump operating mode; if the current air volume compensation mode is heat pump operating mode, then the pressure difference between the target pressure on the low-pressure side of the heat pump operating mode and the actual pressure on the low-pressure side of the heat pump operating mode is calculated. The first air volume compensation amount is obtained by PID regulation based on the pressure difference; If the current air volume compensation mode is a non-heat pump working mode, calculate the pressure difference between the target pressure on the high-pressure side of the non-heat pump working mode and the actual pressure on the high-pressure side of the non-heat pump working mode. The second air volume compensation amount is obtained by PID adjustment based on the pressure difference; the first air volume compensation amount or the second air volume compensation amount is used as the air volume compensation amount of the vehicle thermal management system.

6. A fan control device for an electric vehicle thermal management system, comprising: A processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the electric vehicle thermal management system fan control method as described in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the fan control method of the electric vehicle thermal management system as described in any one of claims 1 to 4.

Images