Control method and device for electric vehicle electronic fan

Abstract

The application provides a control method of an electric vehicle electronic fan, and the method comprises the following steps: S1, determining the current air volume demand of the whole vehicle; S2, decoupling the current air volume demand of the whole vehicle based on the air intake volume at the current vehicle speed to obtain the air volume Q5 required to be provided by the electronic fan; S3, determining the PWM duty cycle corresponding to the air volume Q5 provided by the electronic fan, and controlling the electronic fan based on the PWM duty cycle. By considering the influence of the ambient temperature on the air volume of the electric drive cooling circuit and the air volume of the battery cooling circuit of the electronic fan, the temperature control of the air volume of the electric drive cooling circuit and the water temperature of the battery cooling circuit is facilitated. In addition, while considering the influence of the driving speed on the air intake volume, the required air volume of the electronic fan is decoupled based on the current air intake volume, so that more accurate heat required to be provided by the electronic fan is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal management, and provides a control method and device for an electric vehicle electronic fan. BACKGROUND

[0002] At present, the automobile engine cooling system adopts a clutch fan and an electronic fan, wherein the electronic fan is driven to work by electricity. With the continuous improvement of engine technology, the engine power is continuously increased, resulting in that the heat dissipation of the engine is increasingly large, and further resulting in that the water temperature is increased. Under the limited layout space of the engine compartment, the problem of high water temperature is generally solved by adjusting the fan air volume.

[0003] With the development of automobile technology, the requirement for the NVH of the electronic fan is increasingly high, and the electronic fan controlled by the PWM duty cycle technology is widely used. However, the traditional electronic fan control method mostly adopts open-loop control, and generally only uses a simple linear corresponding relationship, that is, the electronic fan is directly controlled according to the actual water temperature with a higher temperature value in the electric drive cooling loop and the battery cooling loop.

[0004] The above control method has the following problems: due to the fluctuation of the environment temperature, the water temperature of the cooling system is easily fluctuated in a large range, and the accurate and stable control of the water temperature of the cooling system cannot be achieved. SUMMARY

[0005] In view of this, the present application provides a control method for an electric vehicle electronic fan, aiming at improving the above problems.

[0006] Specifically, the technical scheme includes the following:

[0007] In one aspect, the present application provides a control method for an electric vehicle electronic fan, which includes the following steps:

[0008] S1, determining the current air volume demand of the electric vehicle;

[0009] S2, decoupling the current air volume demand of the vehicle based on the air intake volume at the current vehicle speed to obtain the air volume Q5 required to be provided by the electronic fan;

[0010] S3, determining the PWM duty cycle corresponding to the air volume Q5 provided by the electronic fan, and controlling the electronic fan based on the PWM duty cycle.

[0011] In some embodiments, the method for obtaining the current air volume demand of the vehicle is specifically as follows:

[0012] (1) respectively determining the air volume demand Q1 of the air conditioning system, the air volume demand Q2 of the electric drive cooling loop, the air volume demand Q3 of the battery cooling loop, and other air volume demand Q4;

[0013] (2) Arbitrate the air volume requirements Q1, Q2, Q3, and Q4 to obtain the actual air volume Q required by the whole vehicle.

[0014] In some embodiments, the calculation formula of the actual air volume Q required by the whole vehicle is as follows:

[0015] Q max = max{Q1, Q2, Q3, Q4};

[0016] Q = K * Q max ;

[0017]

[0018] In some embodiments, the method for obtaining the air volume Q5 required to be provided by the electronic fan is as follows:

[0019] (1) Simulate by the whole vehicle CFD to generate a mapping table MAP4 of electronic fan duty cycle-vehicle speed-air volume, and find out the vehicle air volume under the current duty cycle and vehicle speed of the electronic fan through the mapping table MAP4;

[0020] (2) Find out the air volume Q5 required to be provided by the electronic fan based on the mapping table MAP5 of whole vehicle air volume requirement-air volume-air volume required to be provided by the electronic fan.

[0021] In some embodiments, the method for determining the PWM duty cycle corresponding to the air volume Q5 provided by the electronic fan is as follows:

[0022] Find out the PWM duty cycle corresponding to the air volume Q5 required to be provided by the electronic fan based on the PWM duty cycle-electronic fan air volume mapping table.

[0023] In some embodiments, the method for obtaining the air volume requirement Q2 of the electric drive cooling circuit is as follows:

[0024] Construct a mapping MAP1 of electric drive cooling circuit water temperature-environmental temperature-air volume requirement;

[0025] Find out the air volume requirement Q2 of the electric drive cooling circuit based on the actual water temperature of the electric drive cooling circuit and the actual temperature of the environment in the mapping MAP1.

[0026] In some embodiments, the method for obtaining the air volume requirement Q3 of the battery cooling circuit is as follows:

[0027] Construct a mapping MAP2 of battery cooling circuit water temperature-environmental temperature-air volume requirement;

[0028] Find out the air volume requirement Q3 of the battery cooling circuit based on the actual water temperature of the battery cooling circuit and the actual temperature of the environment in the mapping MAP2.

[0029] In some embodiments, the method for obtaining other air volume requirement Q4 is specifically as follows:

[0030] The key components with higher front cabin temperature are defined, including: drive motor, drive controller, compressor, DCDC converter;

[0031] The mapping relationship between the temperature of the key components and the occurrence level of potential heat damage, and the mapping relationship between the occurrence level of potential heat damage and the air volume required to eliminate the occurrence of potential heat damage are constructed;

[0032] Based on the actual temperature of the key components, the corresponding occurrence level of potential heat damage is found, and then the air volume Q4 required to eliminate the occurrence of potential heat damage is obtained.

[0033] Embodiments of the present application provide a control device for an electric vehicle electronic fan, the device comprising the following steps:

[0034] The device comprises: an air volume requirement Q1 calculation unit, an air volume requirement Q2 calculation unit, an air volume requirement Q3 calculation unit, and an air volume requirement Q4 calculation unit; an arbitration unit connected to the air volume requirement Q1 calculation unit, the air volume requirement Q2 calculation unit, the air volume requirement Q3 calculation unit, and the air volume requirement Q4 calculation unit; an electronic fan air volume calculation unit connected to the arbitration unit, and a duty cycle calculation unit connected to the electronic fan air volume calculation unit; wherein,

[0035] The air volume requirement Q1 calculation unit is used to calculate the air volume requirement Q1 of the air conditioning system and send it to the arbitration unit; the air volume requirement Q2 calculation unit is used to calculate the air volume requirement Q2 of the electric drive cooling circuit and send it to the arbitration unit; the air volume requirement Q3 calculation unit is used to calculate the air volume requirement Q3 of the battery cooling circuit and send it to the arbitration unit; and the air volume requirement Q4 calculation unit is used to calculate the other air volume requirement Q4 and send it to the arbitration unit;

[0036] The arbitration unit calculates the current air volume requirement of the vehicle based on the received air volume requirement Q1 of the air conditioning system, the air volume requirement Q2 of the electric drive cooling circuit, the air volume requirement Q3 of the battery cooling circuit, and the other air volume requirement Q4;

[0037] The electronic fan air volume calculation unit calculates the air volume Q5 required to be provided by the electronic fan; and the duty cycle calculation unit calculates the PWM duty cycle corresponding to the air volume Q5 provided by the electronic fan.

[0038] The present application considers the influence of ambient temperature on the air volume of the electric drive cooling circuit and the air volume of the battery cooling circuit, which is beneficial to the temperature control of the air volume of the electric drive cooling circuit and the water temperature of the battery cooling circuit. In addition, the present application considers the influence of driving speed on the air volume, and decouples the air volume required by the electronic fan based on the current air volume, to obtain more accurate heat required to be provided by the electronic fan. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A flowchart of a control method for an electric vehicle electronic fan provided in an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the structure of the control device for an electric vehicle electronic fan provided in an embodiment of the present invention;

[0042] 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

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] Unless otherwise defined, all technical terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art.

[0045] To make the technical solutions and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. Figure 1 The flowchart of the control method for an electric vehicle electronic fan provided in an embodiment of the present invention includes the following steps:

[0046] S1. Determine the current airflow requirements of the electric vehicle, which mainly consist of the following four parts:

[0047] (1) Air volume requirement of the air conditioning system Q1:

[0048] The target pressure of the air conditioning system is taken as a target value, the difference between the current actual pressure of the air conditioning system and the target pressure is input into a PID algorithm, the air volume demand of the air conditioning system at the current time is calculated, and the air volume is air volume demand Q1, so as to adjust the actual pressure of the air conditioning system to approach the target pressure.

[0049] (2) The air volume demand Q2 of the electric drive cooling circuit;

[0050] Since the actual water temperature of the electric drive cooling circuit and the actual temperature of the environment have a great influence on the air volume demand of the electric drive cooling circuit, based on this, the air volume required by different electric drive cooling circuit water temperatures and environment temperatures is simulated or tested by a real vehicle, that is, the mapping of the electric drive cooling circuit water temperature-ambient temperature-air volume demand MAP1 is formed, and the air volume demand Q2 of the electric drive cooling circuit is found in the mapping MAP1 based on the actual water temperature of the electric drive cooling circuit and the actual temperature of the environment.

[0051] (3) The air volume demand Q3 of the battery cooling circuit;

[0052] Since the actual water temperature of the battery cooling circuit and the actual temperature of the environment have a great influence on the air volume demand of the battery cooling circuit, based on this, the air volume required by different battery cooling circuit water temperatures and environment temperatures is simulated or tested by a real vehicle, that is, the mapping of the battery cooling circuit water temperature-ambient temperature-air volume demand MAP2 is formed, and the air volume demand Q3 of the battery cooling circuit is found in the mapping MAP2 based on the actual water temperature of the battery cooling circuit and the actual temperature of the environment.

[0053] (4) Other air volume demand Q4:

[0054] According to the actual temperature of the front cabin parts, the potential heat hazard occurrence level is evaluated, and the air volume table is looked up according to the potential heat hazard occurrence level to calculate the required air volume Q4.

[0055] Define the key components of the front cabin with high temperature, including: drive motor, drive controller, compressor, DCDC converter, build the mapping relationship of key component temperature and potential heat hazard occurrence level and the mapping relationship of potential heat hazard occurrence level and the air volume required to eliminate potential heat hazard, based on the actual temperature of the key components to find the corresponding potential heat hazard occurrence level, and then obtain the air volume Q4 required to eliminate potential heat hazard.

[0056] The air volume demand Q1 of the air conditioning system, the air volume demand Q2 of the electric drive cooling circuit, the air volume demand Q3 of the battery cooling circuit and other air volume demand Q4 are arbitrated, and the actual air volume Q required by the whole vehicle is finally calculated, and the calculation formula is as follows:

[0057] Q max =max{Q1、Q2、Q3、Q4};

[0058] Q=K*Qmax ;

[0059]

[0060] Considering the mutual influence of multiple heat dissipation systems such as air conditioning systems, battery / motor cooling systems and the like on the inlet air temperature, the air volume demand is not simply superimposed, and based on CFD simulation data and a large amount of test data, the above air volume arbitration method is summarized, the K value can effectively correct the relationship between the actual air volume demand and the maximum demand air volume in the above four parts of air volume demand, and accurately calculate the real-time demand air volume of the whole vehicle.

[0061] S2, decoupling the current air volume demand of the whole vehicle based on the current inlet air volume of the vehicle, obtaining the air volume Q5 required to be provided by the electronic fan;

[0062] In the embodiment of the application, the actual inlet air volume of the whole vehicle under different electronic fan duty cycles and different vehicle speeds is obtained by simulating the whole vehicle CFD, and then the electronic fan duty cycle-vehicle speed-inlet air volume mapping MAP4 is generated, the inlet air volume of the vehicle under the current time duty cycle and vehicle speed of the electronic fan is found out through MAP4, and the air volume required to be provided by the electronic fan under different whole vehicle air volume demand and vehicle inlet air volume is calibrated to form the whole vehicle air volume demand-inlet air volume-air volume required to be provided by the electronic fan mapping table MAP5, and the air volume Q5 required to be provided by the electronic fan is found out based on the mapping table MAP5, so as to determine the PWM duty cycle of the electronic fan at the next moment, that is, the PWM duty cycle in step S3.

[0063] S3, determine the PWM duty cycle corresponding to the air volume Q5 provided by the electronic fan, and control the electronic fan based on the PWM duty cycle.

[0064] In the embodiment of the application, the performance curve of the electronic fan is determined by whole vehicle CFD simulation, that is, the air volume provided by the electronic fan under different PWM duty cycles, and the PWM duty cycle corresponding to the air volume Q5 provided by the electronic fan is calculated according to the determined performance curve of the electronic fan.

[0065] In the embodiment of the application, in order to avoid the jitter of the electronic fan, the difference between the PWM duty cycle of the electronic fan at the current moment and the PWM duty cycle of the electronic fan at the last moment is calculated, and if the difference is greater than the set PWM duty cycle, the PWM duty cycle of the electronic fan at the current moment is equal to the sum of the PWM duty cycle of the electronic fan at the last moment and the set PWM duty cycle.

[0066] Figure 2 The structure schematic diagram of the control device of the electric vehicle electronic fan provided in the embodiment of the application, only the part related to the embodiment of the application is shown for convenience of description.

[0067] The device comprises: air volume demand Q1 calculation unit, air volume demand Q2 calculation unit, air volume demand Q3 calculation unit and air volume demand Q4 calculation unit; arbitration unit connected with air volume demand Q1 calculation unit, air volume demand Q2 calculation unit, air volume demand Q3 calculation unit and air volume demand Q4 calculation unit; electronic fan air volume calculation unit connected with the arbitration unit, and duty cycle calculation unit connected with the electronic fan air volume calculation unit; wherein,

[0068] The air volume demand Q1 calculation unit is used for calculating the air volume demand Q1 of the air conditioning system and sending to the arbitration unit; the PID algorithm is integrated in the air volume demand Q1 calculation unit, and the difference between the current actual pressure and the target pressure of the air conditioning system is input into the PID algorithm, and the PID algorithm outputs the air volume demand Q1 of the air conditioning system at the current time;

[0069] The air volume demand Q2 calculation unit is used for calculating the air volume demand Q2 of the electric drive cooling circuit and sending to the arbitration unit; the air volume demand Q2 calculation unit is integrated with the mapping MAP1 of the water temperature-environment temperature-air volume demand of the electric drive cooling circuit, the actual water temperature of the electric drive cooling circuit and the actual temperature of the environment are input into the air volume demand Q2 calculation unit, and the air volume demand Q2 calculation unit outputs the air volume demand Q2 of the electric drive cooling circuit;

[0070] The air volume demand Q3 calculation unit is used for calculating the air volume demand Q3 of the battery cooling circuit and sending to the arbitration unit; the air volume demand Q3 calculation unit is integrated with the mapping MAP2 of the water temperature-environment temperature-air volume demand of the battery cooling circuit, the actual water temperature of the battery cooling circuit and the actual temperature of the environment are input into the air volume demand Q3 calculation unit, and the air volume demand Q3 calculation unit outputs the air volume demand Q3 of the battery cooling circuit;

[0071] The air volume demand Q4 calculation unit is used for calculating other air volume demand Q4 and sending to the arbitration unit; the air volume demand Q4 calculation unit is integrated with the mapping relationship between the key component temperature and the potential heat hazard occurrence level and the mapping relationship between the potential heat hazard occurrence level and the air volume required for eliminating the potential heat hazard occurrence, the actual temperature of the key component of the front cabin is input into the air volume demand Q4 calculation unit, and the air volume demand Q4 calculation unit outputs the air volume Q4 required for eliminating the potential heat hazard occurrence.

[0072] The arbitration unit calculates the current air volume demand of the whole vehicle based on the received air volume demand Q1 of the air conditioning system, the air volume demand Q2 of the electric drive cooling circuit, the air volume demand Q3 of the battery cooling circuit and other air volume demand Q4;

[0073] In the embodiment of the application, the arbitration unit calculates the actual air intake Q of the whole vehicle demand based on the following formula, and the formula is as follows:

[0074] Q max= max{Q1, Q2, Q3, Q4};

[0075] Q = K * Q max ;

[0076]

[0077] The electronic fan air volume calculation unit calculates the air volume Q5 required to be provided by the electronic fan;

[0078] The electronic fan duty cycle-vehicle speed-air volume of the sub-fan mapping table MAP4 and the whole vehicle air volume demand-air volume of the sub-fan-provided air volume of the electronic fan mapping table MAP5 are integrated in the electronic fan air volume calculation unit, which are obtained by whole vehicle CFD simulation. The arbitration unit inputs the air volume Q of the whole vehicle demand into the sub-fan provided air volume calculation unit, and inputs the current PWM duty cycle and vehicle speed of the electronic fan into the sub-fan provided air volume calculation unit. The sub-fan provided air volume calculation unit outputs the air volume Q5 required to be provided by the electronic fan.

[0079] The duty cycle calculation unit calculates the PWM duty cycle corresponding to the air volume Q5 provided by the electronic fan;

[0080] The duty cycle calculation unit integrates the air volume provided by the electronic fan under different PWM duty cycles. The air volume Q5 required to be provided by the electronic fan output by the sub-fan provided air volume calculation unit is input into the duty cycle calculation unit. The duty cycle calculation unit outputs the PWM duty cycle of the electronic fan.

[0081] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the application being indicated by the following claims.

[0082] It should be understood that the application is not limited to the precise construction that has been described above and illustrated in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the appended claims.

Claims

1. A control method of an electric vehicle electronic fan, characterized by, The method comprises the following steps: S1, determining the current air volume demand of the whole vehicle; S2, decoupling the current air volume demand of the whole vehicle based on the air intake volume at the current vehicle speed to obtain the air volume Q5 required to be provided by the electronic fan; S3, determining the PWM duty cycle corresponding to the air volume Q5 required to be provided by the electronic fan, and controlling the electronic fan based on the PWM duty cycle; The method for obtaining the current air volume demand of the whole vehicle is specifically as follows: (1) respectively determining the air volume demand Q1 of the air conditioning system, the air volume demand Q2 of the electric drive cooling circuit, the air volume demand Q3 of the battery cooling circuit, and other air volume demand Q4; (2) arbitrating the air volume demand Q1, the air volume demand Q2, the air volume demand Q3, and the air volume demand Q4 to obtain the actual air intake volume Q of the whole vehicle demand; The calculation formula of the actual air intake volume Q of the whole vehicle demand is specifically as follows: Q max = max{Q1, Q2, Q3, Q4}; Q = K * Q max ; The method for obtaining the air volume Q5 required to be provided by the electronic fan is specifically as follows: (1) generating an electronic fan duty cycle-vehicle speed-air intake volume mapping table MAP4 through whole vehicle CFD simulation, and finding out the vehicle air intake volume at the current time of the electronic fan through the mapping table MAP4; (2) finding out the air volume Q5 required to be provided by the electronic fan based on the whole vehicle air volume demand-air intake volume-electronic fan required air volume mapping table MAP5.

2. The control method of the electric vehicle electronic fan according to claim 1, wherein The method for determining the PWM duty cycle corresponding to the air volume Q5 required to be provided by the electronic fan is specifically as follows: Finding out the PWM duty cycle corresponding to the air volume Q5 required to be provided by the electronic fan based on the PWM duty cycle-electronic fan air volume mapping table.

3. The control method of the electric vehicle electronic fan according to claim 1, wherein The method for obtaining the air volume demand Q2 of the electric drive cooling circuit is specifically as follows: Constructing an electric drive cooling circuit water temperature-environment temperature-air volume demand mapping MAP1; Finding out the air volume demand Q2 of the electric drive cooling circuit based on the actual water temperature of the electric drive cooling circuit and the actual temperature of the environment in the mapping MAP1.

4. The control method of the electric vehicle electronic fan according to claim 1, wherein The method for obtaining the air volume demand Q3 of the battery cooling circuit is specifically as follows: Constructing a battery cooling circuit water temperature-environment temperature-air volume demand mapping MAP2; Finding out the air volume demand Q3 of the battery cooling circuit based on the actual water temperature of the battery cooling circuit and the actual temperature of the environment in the mapping MAP2.

5. The control method of the electric vehicle electronic fan according to claim 1, wherein The method for obtaining the other air volume demand Q4 is specifically as follows: Defining key components with high front cabin temperature, including: drive motor, drive controller, compressor, DCDC converter; Constructing a mapping relationship between key component temperature and potential heat hazard occurrence level, and a mapping relationship between potential heat hazard occurrence level and air volume required to eliminate potential heat hazard occurrence; Based on the actual temperature of the key component, the corresponding potential heat hazard occurrence level is found out, and then the air volume Q4 required to eliminate potential heat hazard occurrence is obtained.

6. A control device for an electric vehicle electronic fan for implementing the control method of the electric vehicle electronic fan according to any one of claims 1 to 5, characterized by The device comprises: An air volume demand Q1 calculation unit, an air volume demand Q2 calculation unit, an air volume demand Q3 calculation unit, and an air volume demand Q4 calculation unit; an arbitration unit connected with the air volume demand Q1 calculation unit, the air volume demand Q2 calculation unit, the air volume demand Q3 calculation unit, and the air volume demand Q4 calculation unit; an electronic fan air volume calculation unit connected with the arbitration unit, and a duty cycle calculation unit connected with the electronic fan air volume calculation unit; wherein, The air volume demand Q1 calculation unit is configured to calculate the air volume demand Q1 of the air conditioning system and send the air volume demand Q1 to the arbitration unit; the air volume demand Q2 calculation unit is configured to calculate the air volume demand Q2 of the electric drive cooling circuit and send the air volume demand Q2 to the arbitration unit; the air volume demand Q3 calculation unit is configured to calculate the air volume demand Q3 of the battery cooling circuit and send the air volume demand Q3 to the arbitration unit; and the air volume demand Q4 calculation unit is configured to calculate other air volume demands Q4 and send the other air volume demands Q4 to the arbitration unit. The arbitration unit calculates the current air volume demand of the whole vehicle based on the received air volume demand Q1 of the air conditioning system, the air volume demand Q2 of the electric drive cooling circuit, the air volume demand Q3 of the battery cooling circuit, and the other air volume demands Q4. The electronic fan air volume calculation unit calculates the air volume Q5 required to be provided by the electronic fan; and the duty cycle calculation unit calculates the PWM duty cycle corresponding to the air volume Q5 required to be provided by the electronic fan.

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