A bypass flow control method, device, fuel cell air system and vehicle

Abstract

The present application relates to a bypass flow control method, device, fuel cell air system and vehicle, and relates to the technical field of batteries. The method includes: when the air compressor in the fuel cell air system is in a surge condition, determining a bypass flow request value based on the surge control flow of the air compressor and the flow into the stack; the surge control flow is the minimum flow threshold for the safe operation of the air compressor; determining a feedforward value of the opening degree of the bypass valve in the fuel cell air system based on the bypass flow request value; controlling the opening degree of the bypass valve based on the feedforward value of the opening degree to control the bypass flow of the fuel cell air system. Thus, the feedforward value of the opening degree is used to predict the required opening degree of the bypass valve according to the bypass flow request value, so that the adjustment of the opening degree of the bypass valve can quickly respond to the change of the surge condition of the air compressor. The bypass flow can be quickly adjusted through the feedforward value of the opening degree, so that the air compressor can quickly resume stable operation.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, particularly to the technical field of hydrogen fuel cell vehicles, and specifically to a bypass flow control method, device, fuel cell air system and vehicle. Background Art

[0002] Hydrogen fuel cell vehicles use hydrogen fuel cells as power sources. An air compressor, as an important component of the air system of a hydrogen fuel cell, is used to compress the gas entering the air compressor and then input it to the cathode of the fuel cell stack, participating in the electrochemical reaction inside the fuel cell stack to generate electrical energy to drive the vehicle. During the operation of the air compressor, when the gas flow rate of the air compressor is too low and the pressure ratio between the inlet and outlet is too large, the air compressor will enter the surge working area, affecting the life and performance of the air compressor. Currently, generally, the flow rate of the air compressor is mainly increased to avoid the air compressor entering the surge condition. It is mainly to control the opening degree of the bypass valve to control the air flow rate flowing through the bypass valve, so as to increase the flow rate of the air compressor and make the air compressor out of the surge condition.

[0003] In related technologies, the estimated flow rate into the stack is calculated through an adaptive observation model, and the estimated bypass flow rate is determined based on the estimated flow rate into the stack and the flow rate of the air compressor. Then, the opening degree of the bypass valve is controlled according to the estimated bypass flow rate and the expected bypass flow rate to achieve bypass flow control. In another related technology, the actual bypass control amount of the bypass valve is determined based on the actual bypass air volume flowing through the bypass valve. Based on the actual bypass control amount, the closed-loop control result of the opening degree of the bypass valve is used as the feedback value of the PID control algorithm, and the control target value of the opening degree of the bypass valve is the larger value of the air volume required for diluting the tail gas concentration and the air volume required for suppressing the surge of the air compressor, and the opening degree of the bypass valve is subjected to PID closed-loop control. However, during the operation of the fuel cell air system, parameters such as the air flow rate into the stack and the bypass control flow rate will change rapidly. The above two methods have a time lag in controlling the opening degree of the bypass valve based on the estimated bypass flow rate, the expected bypass flow rate or the feedback opening degree of the bypass valve, which easily leads to unstable bypass flow rate and cannot achieve precise control of the bypass flow rate in the fuel cell air system. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a bypass flow control method, device, fuel cell air system and vehicle, aiming to solve the technical problem of inaccurate bypass flow control in the fuel cell air system in related technologies.

[0005] In order to achieve the above purpose, the technical solutions adopted in the embodiments of the present application are as follows:

[0006] In a first aspect, an embodiment of the present application provides a bypass flow control method, which includes: when the air compressor in the fuel cell air system is in a surge condition, determining a bypass flow request value based on the surge control flow of the air compressor and the flow into the stack; the surge control flow is the minimum flow threshold for the safe operation of the air compressor; determining a feedforward value of the opening of the bypass valve in the fuel cell air system based on the bypass flow request value; and controlling the opening of the bypass valve based on the feedforward value of the opening to control the bypass flow in the fuel cell air system.

[0007] According to the above technical means, the bypass flow request value is determined by the surge control flow to determine the feedforward opening of the bypass valve to adjust the opening of the bypass valve, increasing the air compressor flow, so that the gas flow into the air compressor is not lower than the minimum safe operation threshold, so that the air compressor can get out of the surge condition. Moreover, the feedforward value of the opening of the bypass valve is used to predict the required opening of the bypass valve according to the bypass flow request value, so that the opening adjustment of the bypass valve can quickly respond to the change of the surge condition of the air compressor. Therefore, based on the feedforward value of the opening, the bypass flow can be quickly adjusted, so that the air compressor can quickly resume stable operation and reduce the flow fluctuation in the fuel cell air system caused by the opening adjustment of the bypass valve.

[0008] In a possible implementation manner, determining a bypass flow request value based on the surge control flow of the air compressor and the flow into the stack includes: determining the difference between the surge control flow and the flow into the stack as the bypass flow standard condition value; and converting the bypass flow standard condition value into the bypass flow request value under the current condition of the fuel cell air system based on the ambient temperature and pressure of the fuel cell air system.

[0009] According to the above technical means, taking the difference between the surge control flow and the flow into the stack to determine the bypass flow standard condition value can make the gas flow into the air compressor not lower than the surge control flow while meeting the gas flow demand of the fuel cell stack. Moreover, converting the bypass flow standard condition value into the bypass flow request value under the current condition takes into account the influence of ambient temperature and pressure on the gas state, so as to more accurately control the bypass flow.

[0010] In a possible implementation manner, determining a feedforward value of the opening of the bypass valve in the fuel cell air system based on the bypass flow request value includes: determining the feedforward value of the opening of the bypass valve based on the bypass flow request value, the temperature into the stack, the pressure into the stack, and the ambient pressure.

[0011] According to the above technical means, considering the influence of environmental factors on the physical properties and flow characteristics of the gas through the temperature into the stack, the pressure into the stack, and the ambient pressure, the required opening of the bypass valve can be determined more accurately, improving the control accuracy of the bypass flow.

[0012] In a possible implementation manner, determining a feedforward value of the opening degree of the bypass valve based on a bypass flow request value, an inlet stack temperature, an inlet stack pressure, and an ambient pressure includes: determining a functional correspondence between the opening degree of the bypass valve and the inlet stack pressure, the ambient pressure, the inlet stack temperature, and the bypass flow request value based on a bypass valve flow calculation model; the bypass valve flow calculation model is used to characterize the quantitative relationship between the bypass flow of the fuel cell air system and the pressure and temperature; substituting the bypass flow request value, the inlet stack temperature, the inlet stack pressure, and the ambient pressure into the functional correspondence to obtain the feedforward value of the opening degree of the bypass valve.

[0013] According to the above technical means, through the bypass valve flow calculation model, the influence of various factors such as the inlet stack pressure, the ambient pressure, and the inlet stack temperature on the bypass flow can be comprehensively considered, and the control error of the bypass flow can be reduced. Thus, a feedforward value of the opening degree of the bypass valve matching the actual working condition can be obtained, and the bypass flow can be controlled more accurately.

[0014] In a possible implementation manner, controlling the opening degree of the bypass valve based on the feedforward value of the opening degree includes: determining an opening degree compensation value of the bypass valve of the fuel cell air system based on the bypass flow request value; controlling the opening degree of the bypass valve based on the feedforward value of the opening degree and the opening degree compensation value.

[0015] According to the above technical means, the opening degree compensation value can correct the deviation of the feedforward value of the opening degree according to the actual operation condition of the fuel cell air system. Controlling the opening degree of the bypass valve based on the feedforward value of the opening degree and the opening degree compensation value enables the opening degree of the bypass valve to quickly and accurately adapt to the dynamic change of the fuel cell air system, and the actual opening degree of the bypass valve can more accurately meet the bypass flow request value, improving the control accuracy of the bypass flow.

[0016] In a possible implementation manner, determining the opening degree compensation value of the bypass valve of the fuel cell air system based on the bypass flow request value includes: inputting the difference between the bypass flow request value and the actual bypass flow value into a proportional integral derivative (PID) controller to obtain the opening degree compensation value of the bypass valve.

[0017] According to the above technical means, the PID controller can adjust the opening degree compensation value according to the rapid difference between the bypass flow request value and the actual value, reduce the error of the bypass flow, make the bypass flow quickly approach the bypass flow request value, and improve the control accuracy of the platform flow.

[0018] In a possible implementation, the surge control flow rate is determined as follows: based on the ratio between the inlet pressure of the fuel cell air system and the ambient pressure, the compression ratio of the air compressor is determined; based on the compression ratio of the air compressor and the surge control line, the surge control flow rate is determined; the surge control line is used to characterize the corresponding relationship between the compression ratio of the air compressor and the minimum flow rate threshold for the safe operation of the air compressor.

[0019] According to the above technical means, by determining the surge control flow rate through the surge control line, the gas flow rate entering the air compressor is always not lower than the minimum safe operation flow rate threshold, which can avoid the surge condition or quickly get out of the surge condition, ensuring the safe and stable operation of the air compressor.

[0020] In a possible implementation, the method further includes: obtaining the compression ratio and the air compressor flow rate of the fuel cell air system at different air compressor speeds; based on the compression ratio and the air compressor flow rate of the fuel cell air system at different air compressor speeds, determining the air compressor surge line; the air compressor surge line is used to characterize the corresponding relationship between the compression ratio of the air compressor and the air compressor flow rate when surge occurs at different air compressor speeds of the fuel cell air system; based on the air compressor surge line, determining the surge control line.

[0021] According to the above technical means, through the compression ratio and the air compressor flow rate of the fuel cell air system at different air compressor speeds, the air compressor surge line can be accurately determined. The accuracy of the surge control line is improved, and the surge boundary of the air compressor is clarified. So as to more accurately control the bypass flow rate based on the surge boundary value of the air compressor.

[0022] In a possible implementation, when the surge control flow rate is greater than the inlet flow rate, the air compressor of the fuel cell air system is in a surge condition.

[0023] According to the above technical means, through the surge control flow rate and the inlet flow rate, it can be accurately determined whether the air compressor is in a surge condition. So as to quickly adjust the opening of the bypass valve and increase the air compressor flow rate when the air compressor is in a surge condition, so that the air compressor gets out of the surge condition.

[0024] In a second aspect, an embodiment of the present application provides a bypass flow rate control device, which includes: a determination module and a control module. The determination module is used to, when the air compressor of the fuel cell air system is in a surge condition, based on the surge control flow rate and the inlet flow rate of the air compressor, determine a bypass flow rate request value; the surge control flow rate is the minimum flow rate threshold for the safe operation of the air compressor; the determination module is further used to, based on the bypass flow rate request value, determine a feedforward value of the opening of the bypass valve of the fuel cell air system; the control module is used to, based on the feedforward value of the opening, control the opening of the bypass valve to control the bypass flow rate of the fuel cell air system.

[0025] In a possible implementation, the determination module is specifically configured to determine the difference between the surge control flow rate and the flow rate into the stack as the standard condition value of the bypass flow rate; and based on the ambient temperature and pressure of the fuel cell air system, convert the standard condition value of the bypass flow rate into the bypass flow rate request value under the current working condition of the fuel cell air system.

[0026] In a possible implementation, the determination module is specifically configured to determine the feedforward value of the opening degree of the bypass valve based on the bypass flow rate request value, the temperature into the stack, the pressure into the stack, and the ambient pressure.

[0027] In a possible implementation, the determination module is specifically configured to determine the functional correspondence between the opening degree of the bypass valve and the pressure into the stack, the ambient pressure, the temperature into the stack, and the bypass flow rate request value based on the bypass valve flow rate calculation model; the bypass valve flow rate calculation model is used to characterize the quantitative relationship between the bypass flow rate of the fuel cell air system and the pressure and temperature; substitute the bypass flow rate request value, the temperature into the stack, the pressure into the stack, and the ambient pressure into the functional correspondence to obtain the feedforward value of the opening degree of the bypass valve.

[0028] In a possible implementation, the control module is specifically configured to determine the opening degree compensation value of the bypass valve of the fuel cell air system based on the bypass flow rate request value; and control the opening degree of the bypass valve based on the feedforward value of the opening degree and the opening degree compensation value.

[0029] In a possible implementation, the control module is specifically configured to input the difference between the bypass flow rate request value and the actual bypass flow rate into a PID controller to obtain the opening degree compensation value of the bypass valve.

[0030] In a possible implementation, the surge control flow rate is determined in the following manner: based on the ratio between the pressure into the stack and the ambient pressure of the fuel cell air system, determine the compression ratio of the air compressor; based on the compression ratio of the air compressor and the surge control line, determine the surge control flow rate; the surge control line is used to characterize the correspondence between the compression ratio of the air compressor and the minimum flow rate threshold for the safe operation of the air compressor.

[0031] In a possible implementation, the above-mentioned bypass flow rate control device further includes: an acquisition module. The acquisition module is used to acquire the compression ratio and the flow rate of the air compressor of the fuel cell air system at different air compressor speeds; the determination module is further configured to determine the air compressor surge line based on the compression ratio and the flow rate of the air compressor of the fuel cell air system at different air compressor speeds; the air compressor surge line is used to characterize the correspondence between the compression ratio and the flow rate of the air compressor when surge occurs at different air compressor speeds of the fuel cell air system; the determination module is further configured to determine the surge control line based on the air compressor surge line.

[0032] In a possible implementation, when the surge control flow rate is greater than the flow rate into the stack, the air compressor of the fuel cell air system is in a surge condition.

[0033] In a third aspect, an embodiment of the present application provides a fuel cell air system, which includes: an air compressor, a bypass valve, and a controller; the air compressor is configured to compress the gas entering the air compressor; the bypass valve is configured to control the bypass flow rate of the fuel cell air system; the controller is configured to, when the air compressor is in a surge condition, control the opening of the bypass valve based on the opening feedforward value and the opening compensation value of the bypass valve, and adjust the gas flow rate flowing through the bypass valve so that the air compressor gets out of the surge condition.

[0034] In a fourth aspect, an embodiment of the present application provides a vehicle, which includes: a processor; a memory for storing executable instructions of the processor; wherein, the processor is configured to execute the instructions to implement the bypass flow rate control method of any one of the above embodiments.

[0035] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, on which computer program instructions are stored, and when the computer program instructions are executed by a processor, the bypass flow rate control method of any one of the above embodiments is implemented.

[0036] In a sixth aspect, an embodiment of the present application provides a computer program product, which includes computer program instructions, and when the computer program instructions are executed by a processor, the bypass flow rate control method of any one of the above embodiments is implemented.

[0037] It should be noted that the technical effects brought by any implementation manner in the second aspect to the sixth aspect can refer to the technical effects brought by the corresponding implementation manner in the first aspect, which will not be elaborated here.

[0038] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application, and do not constitute an improper limitation to the present application.

[0040] Figure 1 is a schematic structural diagram of a fuel cell air system shown according to an exemplary embodiment;

[0041] Figure 2 is a schematic diagram of the gas direction of a fuel cell air system shown according to an exemplary embodiment;

[0042] Figure 3 is a flowchart of a bypass flow control method shown according to an exemplary embodiment;

[0043] Figure 4 is a flowchart of another bypass flow control method shown according to an exemplary embodiment;

[0044] Figure 5 is a flowchart of yet another bypass flow control method shown according to an exemplary embodiment;

[0045] Figure 6 is a flowchart of yet another bypass flow control method shown according to an exemplary embodiment;

[0046] Figure 7 is a schematic diagram of the opening control logic of a bypass valve shown according to an exemplary embodiment;

[0047] Figure 8 is a flowchart of yet another bypass flow control method shown according to an exemplary embodiment;

[0048] Figure 9 is a schematic diagram of a compressor surge line and a surge control line shown according to an exemplary embodiment;

[0049] Figure 10 is a flowchart of yet another bypass flow control method shown according to an exemplary embodiment;

[0050] Figure 11 is a block diagram of a bypass flow control device shown according to an exemplary embodiment;

[0051] Figure 12 is a block diagram of a vehicle shown according to an exemplary embodiment. Detailed implementation manners

[0052] In order to enable those of ordinary skill in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0053] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order different from those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0054] In the embodiments of the present application, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, article or device including a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the presence of additional identical elements in the process, article or device including such element.

[0055] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner.

[0056] As described in the background art, the surge condition will damage the life of the air compressor and degrade the performance of the air compressor. Methods for avoiding entering the surge condition or getting out of the surge condition include increasing the air compressor flow rate and reducing the back pressure of the air compressor. In a vehicle hydrogen fuel cell system, the air compressor surge is generally avoided by increasing the air compressor flow rate. Specifically, a pipeline is connected from the outlet end of the intercooler in the fuel cell air system to the tail exhaust, and a bypass valve is provided on the pipeline to control the opening and closing of the pipeline. The outlet end of the air compressor is connected to the inlet end of the intercooler. When it is monitored that the air compressor is about to enter the surge condition, the air flow rate flowing through the bypass valve is controlled by controlling the opening of the bypass valve to increase the air compressor flow rate, so that the air compressor gets out of the surge condition. Therefore, precise control of the bypass flow rate is the key to avoiding the surge condition.

[0057] In the related art, an adaptive feedforward control quantity of the bypass valve opening is obtained by inverse-solving the bypass flow rate expected value, and the difference between the bypass flow rate expected value and the bypass flow rate estimated value is input into an integral controller to obtain a correction quantity of the bypass valve opening. Finally, the opening of the bypass valve is controlled according to the adaptive feedforward control quantity and the correction quantity to achieve the control of the bypass flow rate. However, this method requires the setting of a complex observer to obtain the bypass flow rate expected value and the bypass flow rate estimated value for controlling the bypass flow rate. It is not conducive to engineering practice, and the complex observer affects the control speed of the bypass flow rate, resulting in inaccurate control of the bypass flow rate in the fuel cell air system.

[0058] In view of this, the present application provides a bypass flow control method. The bypass flow request value is determined by the surge control flow, so as to determine the feedforward opening of the bypass valve to adjust the opening of the bypass valve, increasing the air compressor flow rate, such that the gas flow rate entering the air compressor is not lower than the minimum safe operating volume threshold, so that the air compressor can get out of the surge condition. Moreover, the opening feedforward value of the bypass valve is used to predict the required opening of the bypass valve according to the bypass flow request value, such that the opening adjustment of the bypass valve can quickly respond to the change of the air compressor surge condition. The bypass flow can be quickly adjusted through the opening feedforward value, so that the air compressor can quickly resume stable operation.

[0059] For ease of understanding, the bypass flow control method provided by the present application will be specifically introduced below in conjunction with the accompanying drawings.

[0060] In some embodiments, the execution subject of the bypass flow control method provided by the embodiments of the present application may be a controller, a fuel cell air system, a battery system, a vehicle controller, or any device or equipment that can control the opening of the bypass valve in the battery cooling system. The embodiments of the present application do not make any limitations thereto.

[0061] Figure 1 is a schematic structural diagram of a fuel cell air system shown according to an exemplary embodiment. As Figure 1 shown, the fuel cell air system 100 may include: an air filter 101, an air compressor 102, an intercooler 103, a bypass valve 104, a shut-off valve 105, an electrolytic stack 106, a back pressure valve 107, a flow meter 108, and a pressure gauge 109.

[0062] Among them, the air filter 101, the air compressor 102, and the intercooler 103 are connected in sequence. One side outlet end of the intercooler 103 is connected to the bypass valve 104, and the other side outlet end is connected to the shut-off valve 105. The shut-off valve 105, the electrolytic stack 106, and the back pressure valve 107 are connected in sequence. The flow meter 108 is arranged at the inlet end of the air compressor 102. The pressure gauge 109 is arranged at the outlet end of the intercooler 103 on the side of the shut-off valve 105.

[0063] In some embodiments, the air filter 101 is used to filter impurities (such as dust, particles, etc.) in the gas entering the fuel cell air system 100 to avoid damaging or blocking the air passage.

[0064] In some embodiments, the air compressor 102 is used to compress the gas entering the air compressor 102.

[0065] In some embodiments, the air compressor 102 is used to boost the gas entering the air compressor 102 to increase the oxygen concentration and meet the high-pressure environment required for the reaction of the electrolytic stack 106.

[0066] In some embodiments, the intercooler 103 is used to cool the high-temperature gas pressurized by the air compressor 102, reduce the gas temperature, and prevent the fuel cell stack from decreasing in efficiency or being damaged due to overheating.

[0067] In some embodiments, the bypass valve 104 is used to control the bypass flow rate of the fuel cell air system 100.

[0068] In some embodiments, the bypass valve 104 is also used to introduce part of the gas into the exhaust pipe during the shutdown or purging of the fuel cell stack 106 to dilute the residual hydrogen discharged from the anode side.

[0069] In some embodiments, the shut-off valve 105 is used to cut off the gas path during the shutdown or maintenance of the fuel cell air system 100 to prevent gas backflow or pressure leakage.

[0070] In some embodiments, the fuel cell stack 106 is used to convert hydrogen and oxygen into electrical energy through an electrochemical reaction.

[0071] In some embodiments, the back pressure valve 107 is used to maintain a constant outlet pressure of the fuel cell air system 100 and prevent the operating point of the air compressor 102 from shifting or surging due to back pressure fluctuations.

[0072] In some embodiments, the flow meter 108 is used to detect the gas flow rate entering the air compressor 102, i.e., the air compressor flow rate. The pressure gauge 109 is used to detect the outlet gas pressure of the intercooler 103 on the side of the shut-off valve 105, i.e., the inlet stack pressure.

[0073] In some embodiments, the gas entering the fuel cell air system 100 for reaction can bypass to the atmosphere through the back pressure valve 107 and / or the bypass valve 104.

[0074] In some embodiments, the fuel cell air system 100 further includes a controller (not shown in the figure). The controller is used to control the opening of the bypass valve 104 based on the opening feedforward value and the opening compensation value of the bypass valve 104 when the air compressor 102 is in a surging condition, and adjust the gas flow rate flowing through the bypass valve 104 so that the air compressor 102 gets out of the surging condition.

[0075] In some embodiments, the controller can be a PID controller.

[0076] In some embodiments, a thermometer (not shown in the figure) is further arranged between the intercooler 103 and the shut-off valve 105, and the thermometer is used to detect the inlet stack temperature of the gas.

[0077] In some embodiments, the gas flowing through the fuel cell air system 100 can be air, pure oxygen, oxygen-enriched air, inert gas or other mixed gases, which can be set based on the actual requirements of the fuel cell stack 106, and the embodiments of the present application do not limit this.

[0078] In some embodiments, Figure 2 is a schematic diagram of the gas direction of a fuel cell air system shown according to an exemplary embodiment, as Figure 2 shown. After the gas is filtered by the air filter 101, it is compressed, pressurized, and heated by the air compressor 102, then cooled by the intercooler 103, and enters the stack to participate in the electrochemical reaction. The bypass valve 104 is located between the intercooler 103 and the tail exhaust. The gas is divided into two branches at the outlet of the intercooler 103. One branch goes to the inside of the stack 106 through the check valve 105 when the check valve 105 and the back pressure valve 107 are opened. The gas flow rate of this branch is the inlet stack flow rate. The other branch is discharged through the bypass valve 104 when the bypass valve 104 is opened. The gas flow rate of this branch is the bypass flow rate.

[0079] In some embodiments, during the operation of the stack 106, the inlet stack flow rate and the inlet stack pressure of the gas can be set based on the actual current request of the stack 106, so that the fuel cell air system 100 supplies gas to the cathode side of the stack 106. When the bypass valve 104 is closed, the inlet stack flow rate is equal to the air compressor flow rate. When the bypass valve is opened, the inlet stack flow rate is equal to the air compressor flow rate minus the bypass flow rate.

[0080] Figure 3 is a flowchart of a bypass flow control method shown according to an exemplary embodiment, as Figure 3 shown. The bypass flow control method includes the following steps:

[0081] S301. When the air compressor of the fuel cell air system is in a surge condition, determine the bypass flow rate request value based on the surge control flow rate of the air compressor and the inlet stack flow rate.

[0082] Among them, the surge control flow rate is the minimum flow rate threshold for the safe operation of the air compressor.

[0083] In some embodiments, when the surge control flow rate is greater than the inlet stack flow rate, the air compressor of the fuel cell air system is in a surge condition.

[0084] A possible implementation is that when the surge control flow rate is greater than the inlet stack flow rate, it means that the minimum flow rate threshold for the safe operation of the air compressor is greater than the inlet stack flow rate of the stack. Then the air compressor flow rate is less than the minimum flow rate threshold for the safe operation of the air compressor, the air compressor flow rate is too low, and the air compressor enters a surge condition.

[0085] In some embodiments, when the surge control flow rate is greater than the flow rate into the stack, the bypass flow rate request value required for the bypass valve can be calculated based on the surge control flow rate and the flow rate into the stack, so as to increase the bypass flow rate of the fuel cell air system by controlling the bypass valve, enabling the air compressor to get out of the surge condition and meeting the requirements of the flow rate and pressure into the stack of the fuel cell stack.

[0086] It should be noted that when the surge control flow rate is less than or equal to the flow rate into the stack, it means that the flow rate of the air compressor is greater than or equal to the minimum flow rate threshold for the safe operation of the air compressor, and the air compressor is in a non-surge condition. Then the bypass flow rate request value is zero, and there is no need to open the bypass valve.

[0087] S302. Determine the feedforward value of the opening degree of the bypass valve of the fuel cell air system based on the bypass flow rate request value.

[0088] Among them, the feedforward opening degree value is used to predict the required opening degree of the bypass valve based on the bypass flow rate request value, and pre-compensate the opening degree of the bypass valve, so that the bypass flow rate of the fuel cell air system reaches the bypass flow rate request value.

[0089] In some embodiments, the above step S301 can be implemented as: determining the feedforward value of the opening degree of the bypass valve based on the bypass flow rate request value, the temperature into the stack, the pressure into the stack, and the ambient pressure.

[0090] A possible implementation method is to combine the bypass flow rate request value with the current temperature into the stack, pressure into the stack, and ambient pressure of the fuel cell air system to predict the opening degree of the bypass valve required for the fuel cell air system to get out of the surge condition under the current working condition, so as to obtain the feedforward value of the opening degree of the bypass valve.

[0091] S303. Control the opening degree of the bypass valve based on the feedforward value of the opening degree to control the bypass flow rate of the fuel cell air system.

[0092] In some embodiments, the opening degree of the bypass valve can be adjusted based on the feedforward value of the opening degree to adjust the bypass flow rate through the bypass valve and increase the flow rate of the air compressor, so that the air compressor gets out of the surge condition.

[0093] It should be understood that by determining the bypass flow rate request value through the surge control flow rate, determining the feedforward opening degree of the bypass valve to adjust the opening degree of the bypass valve, the flow rate of the air compressor is increased, so that the gas flow rate entering the air compressor is not lower than the minimum safe operation threshold, so that the air compressor gets out of the surge condition.

[0094] In some embodiments, as Figure 4 shown, the above step S301 can be specifically implemented as the following steps S3011 - S3012:

[0095] S3011. Determine the bypass flow rate standard condition value as the difference between the surge control flow rate and the flow rate into the stack.

[0096] S3012. Convert the by-pass flow standard condition value into the by-pass flow request value under the current working condition of the fuel cell air system based on the ambient temperature and pressure of the fuel cell air system.

[0097] In a possible implementation, when the air compressor in the fuel cell air system is in a surge working condition, the by-pass flow standard condition value is equal to the difference between the surge control flow and the in-stack flow. Perform standardization processing on the by-pass flow standard condition value to convert the by-pass flow standard condition value into the by-pass flow request value under the current ambient temperature and current pressure conditions of the fuel cell air system.

[0098] Exemplarily, the by-pass flow request value can be determined through the following expressions (1) and (2):

[0099] ;

[0100] ;

[0101] Wherein, represents the by-pass flow standard condition value. represents the surge control flow. represents the current in-stack flow of the fuel cell air system. represents the by-pass flow request value. represents the ambient temperature of the fuel cell air system under standard working conditions. represents the ambient temperature of the fuel cell air system under the current working condition. represents the pressure of the fuel cell air system under standard working conditions. represents the pressure of the fuel cell air system under the current working condition. The ambient temperature and pressure of the fuel cell air system under standard working conditions are set by those skilled in the art according to the characteristics and requirements of the fuel cell air system, and the embodiments of the present application do not limit this.

[0102] It should be understood that determining the difference between the surge control flow and the in-stack flow as the by-pass flow standard condition value can, while meeting the flow requirements of the fuel cell stack, ensure that the gas flow entering the air compressor is not lower than the surge control flow. Moreover, converting the by-pass flow standard condition value into the by-pass flow request value under the current working condition takes into account the influence of ambient temperature and pressure on the gas state, and can more accurately control the by-pass flow.

[0103] In some embodiments, as Figure 5 shown, the above step S302 can be specifically implemented as the following steps S3021 - S3022:

[0104] S3021. Based on the bypass valve flow calculation model, determine the functional correspondence between the bypass valve opening and the inlet pressure, ambient pressure, inlet temperature, and bypass flow request value.

[0105] Among them, the bypass valve flow calculation model is used to characterize the quantitative relationship between the bypass flow of the fuel cell air system and pressure and temperature.

[0106] S3022. Substitute the bypass flow request value, inlet temperature, inlet pressure, and ambient pressure into the functional correspondence to obtain the feedforward value of the bypass valve opening.

[0107] A possible implementation is that the bypass valve flow calculation model is as shown in the following expression (3):

[0108] ;

[0109] Among them, represents the bypass flow. represents the flow coefficient of the bypass valve at different openings, has a one-dimensional data mapping relationship with the bypass valve opening and is used to reflect the relationship between the flow capacity of the bypass valve and the opening. A T represents the effective flow cross-sectional area of the bypass valve corresponding to different openings, with the unit of m 2 . P 1Byp represents the upstream pressure of the bypass valve, with the unit of Pa, P 1Byp is equivalent to the inlet pressure P inStk . P 2Byp represents the downstream pressure of the bypass valve, with the unit of Pa, P 2Byp is equivalent to the ambient pressure. T 1Byp represents the upstream air temperature of the bypass valve, with the unit of K, T 1Byp is equivalent to the inlet temperature T inStk . r represents the ideal gas constant, with a value of 287 J / (kg·K) . k represents the adiabatic index. In the case where the gas in the fuel cell air system is air, k the value of

[0110] Among them, the effective flow cross-sectional area A T of the bypass valve corresponding to different openings is determined by the following expression (4):

[0111] ;

[0112] Among them, represents the opening degree of the bypass valve, with the unit of °. D represents the diameter of the bypass valve, with the unit of m.

[0113] In addition, the relationship between the bypass flow request value, the temperature entering the reactor, the pressure entering the reactor, the ambient pressure and the feed-forward value of the opening degree of the bypass valve is shown in the following expression (5):

[0114] ;

[0115] Among them, represents the feed-forward value of the opening degree of the bypass valve. represents the bypass flow request value. represents the pressure entering the reactor. represents the ambient pressure. represents the temperature entering the reactor.

[0116] Combining the above expressions (3), (4), and (5), when the bypass flow request is known, the following expression (6) can be obtained:

[0117] ;

[0118] It should be noted that in actual engineering applications, generally the temperature entering the reactor is used to replace the temperature upstream of the bypass valve , the pressure entering the reactor is used to replace the pressure upstream of the bypass valve , and the ambient pressure is used to replace the pressure downstream of the bypass valve . Therefore, the above expression (6) can be transformed into the following expression (7):

[0119] ;

[0120] The D in the above expression (7) represents the diameter of the bypass valve, which is generally a constant. Therefore, can be regarded as a unary function of the opening degree of the bypass valve . And the flow coefficient is a structural characteristic parameter related to the opening degree of the bypass valve. can be regarded as a unary function of the opening degree of the bypass valve . Therefore, in the above expression (7), can be regarded as a unary function of the opening degree of the bypass valve , as shown in the following expression (8):

[0121] ;

[0122] Combining the above expressions (7) and (8) gives the following expression (9):

[0123] ;

[0124] As can be seen from the above expression (9), since r and k are constants, can be regarded as a function of the upstream and downstream pressure ratio of the bypass valve, the inlet pressure , the inlet temperature , and the bypass flow request . Therefore, substituting the bypass flow request value, the inlet temperature, the inlet pressure, and the ambient pressure into the above expression (9) can obtain . And is a function of the bypass valve opening . By inverse calibration fitting , the feedforward opening of the bypass valve under different bypass flow requests can be obtained.

[0125] It should be noted that the process of inverse calibration fitting is as follows: Build a fuel cell air system test bench based on the structure of the fuel cell air system, and close the shut-off valve and the back pressure valve completely. Increase the opening of the bypass valve from 0° to 90° at a preset interval. At each opening of the bypass valve, use a PID controller to control the speed of the air compressor so that the upstream and downstream pressure ratio of the bypass valve reaches the set value. Collect the upstream and downstream pressure ratio of the bypass valve, the air compressor flow rate (i.e., the bypass flow rate), the inlet temperature, the ambient pressure, and the inlet pressure at each opening of the bypass valve. Among them, during the process of increasing the opening of the bypass valve from 0° to 90°, the upstream and downstream pressure ratio of the bypass valve decreases from 1 to the pressure ratio at which the air compressor surges at a preset interval. The upstream and downstream pressure ratio of the bypass valve is the ratio between the ambient pressure and the inlet pressure. Substituting the collected bypass flow rate, inlet pressure, inlet temperature, and ambient pressure into the above expression (9) can obtain the corresponding under different bypass valve openings. Fitting the corresponding under different bypass valve openings and the corresponding bypass valve opening can obtain the corresponding relationship between and , as shown in the following expression (10):

[0126]

[0127] ;

[0127] It should be understood that through the bypass valve flow calculation model, the influence of various factors such as the inlet pressure, the ambient pressure, and the inlet temperature on the bypass flow rate can be comprehensively considered, the control error of the bypass flow rate can be reduced, the required opening of the bypass valve can be determined more accurately, and the control accuracy of the bypass flow rate is improved.

[0128] In some embodiments, such as Figure 6 shown, the above step S303 can be specifically implemented through the following steps S3031 - S3032:

[0129] S3031. Determine the opening compensation value of the bypass valve of the fuel cell air system based on the bypass flow request value.

[0130] In some embodiments, the above step S3031 can be implemented as: input the difference between the bypass flow request value and the actual bypass flow value into a PID controller to obtain the opening compensation value of the bypass valve.

[0131] A possible implementation is to perform PID closed-loop control on the opening of the bypass valve through a PID controller to achieve precise control of the bypass flow. Therefore, by inputting the difference between the bypass flow request value and the actual bypass flow value into the PID controller, the opening compensation value of the bypass valve can be obtained.

[0132] It should be noted that the actual bypass flow value is obtained as follows: measure the actual bypass flow value by arranging a flow meter at the inlet end of the bypass valve or calculate the actual bypass flow value through a throttle valve model. And, since the gas flow in the fuel cell air system can quickly follow the changes in the air compressor speed and valve body opening. Therefore, the transient air compressor flow, bypass flow, and in-stack flow can be used to reflect the gas flow situation in the fuel cell air system.

[0133] S3032. Control the opening of the bypass valve based on the opening feedforward value and the opening compensation value.

[0134] A possible implementation is to jointly control the opening of the bypass valve based on the opening compensation amount of the bypass valve and the opening feedforward value of the bypass valve to achieve control of the bypass flow, avoid surging of the air compressor, and ensure that the in-stack flow and in-stack pressure of the fuel cell air system maintain the normal operation of the fuel cell stack.

[0135] Figure 7 is a schematic diagram of the opening control logic of a bypass valve shown according to an exemplary embodiment. As Figure 7 shown, input the ambient pressure, in-stack pressure, in-stack temperature, and bypass flow request value into the bypass valve feedforward opening calculation unit to obtain the opening feedforward value of the bypass valve. Input the difference between the bypass flow request value and the actual bypass flow value into the PID controller to obtain the opening compensation value of the bypass valve. Based on the opening feedforward value and the opening compensation value of the bypass valve, obtain the bypass valve opening request to control the bypass valve in the fuel cell air system. The actual bypass flow value can be collected from the fuel cell air system.

[0136] It should be understood that the opening degree of the bypass valve is controlled by the opening degree feedforward value and the opening degree compensation value. The control speed of the bypass flow is improved, so that the gas flow of the fuel cell air system can be stabilized in a relatively short time. While quickly avoiding the surge condition of the air compressor, the fluctuation of the inlet stack flow caused by the opening of the bypass valve is suppressed, and the electrochemical reaction of the fuel cell stack is prevented from being affected.

[0137] In some embodiments, as Figure 8 shown, the bypass flow control method provided by the embodiment of the present application further includes the following steps S801 - S803:

[0138] S801. Obtain the compressor pressure ratio and the compressor flow rate of the fuel cell air system at different air compressor speeds.

[0139] S802. Determine the compressor surge line based on the compressor pressure ratio and the compressor flow rate of the fuel cell air system at different air compressor speeds.

[0140] Among them, the compressor surge line is used to characterize the corresponding relationship between the compressor pressure ratio and the compressor flow rate when the fuel cell air system surges at different air compressor speeds.

[0141] A possible implementation is to regard the air filter, the air compressor, the intercooler and the connecting pipes between the components in the fuel cell air system as a whole component. With a preset air compressor speed interval, the air compressor speed is gradually increased from the lowest speed to the highest speed, and at each air compressor speed point, the pressure at the outlet of the intercooler is controlled. With a preset pressure interval, the ambient pressure is gradually increased to the pressure when the air compressor surges. The back pressure valve can be used to control the outlet pressure at the outlet of the intercooler. Collect the air filter inlet pressure, the air filter inlet temperature, the intercooler outlet pressure, the air compressor speed, and the air compressor flow rate at each air compressor speed point and each intercooler outlet pressure point.

[0142] Based on the preset standard temperature and standard pressure, the collected data such as the air compressor speed and the air compressor flow rate are standardized through the following expressions (11) and (12) to obtain the standard air compressor speed and the standard air compressor flow rate:

[0143] ;

[0144] ;

[0145] Among them, represents the standard air compressor speed. represents the standard air compressor flow rate. represents the collected air compressor speed. represents the standard temperature. represents the collected air filter inlet temperature. Represents the collected air compressor flow rate. Represents the standard condition pressure. Represents the collected air filter inlet pressure.

[0146] And determine the air compressor pressure ratio based on the following expression (13):

[0147] ;

[0148] Wherein, Represents the air compressor pressure ratio. Represents the collected air filter inlet pressure. Represents the collected intercooler outlet pressure.

[0149] Fit the air compressor pressure ratio and the air compressor standard condition flow rate at each standard condition speed. Take the air compressor standard condition flow rate as the horizontal axis and the air compressor pressure ratio as the vertical axis to obtain the corresponding relationship of the air compressor standard condition flow rate. In this corresponding relationship of the air compressor standard condition flow rate, at each standard condition speed, the air compressor has a corresponding maximum air compressor pressure ratio value. When the pressure ratio of the air compressor is higher than the maximum air compressor pressure ratio value, the air compressor will surge. The air compressor standard condition flow rate corresponding to the maximum air compressor pressure ratio value is the minimum flow rate that the air compressor can reach at this standard condition speed. Fit the minimum standard condition flow rate and the maximum air compressor pressure ratio value at each standard condition speed to obtain the air compressor surge line at each standard condition speed.

[0150] S803. Determine the surge control line based on the air compressor surge line.

[0151] A possible implementation method. In engineering practice, usually shift the air compressor surge line to the right along the horizontal axis where the air compressor standard condition flow rate is located by a preset range to obtain the air compressor surge control line. Wherein, the preset range can be 5% - 10% of the minimum standard condition flow rate.

[0152] Figure 9 Is a schematic diagram of an air compressor surge line and a surge control line shown according to an exemplary embodiment. As Figure 9 Shown, the horizontal axis is the air compressor standard condition flow rate, with the unit of g / s. The vertical axis is the air compressor pressure ratio. The solid line represents the air compressor surge line. The dashed line represents the air compressor surge control line. Shift the air compressor surge line to the right along the horizontal axis by a preset range to obtain the air compressor surge control line.

[0153] It should be understood that by determining the surge control flow rate through the surge control line, the gas flow rate entering the air compressor is always not lower than the minimum safe operating flow rate threshold, which can avoid the surge condition or quickly get out of the surge condition, enabling the safe and stable operation of the air compressor. And by combining the pressure ratio of the air compressor with the surge control line to determine the surge control flow rate, the surge control flow rate can be adjusted according to the actual working conditions of the fuel cell air system, so as to accurately control the bypass flow rate under different working conditions.

[0154] In some embodiments, as Figure 10 shown, the surge control flow rate is determined through the following steps S1001 - S1002:

[0155] S1001. Determine the compression ratio of the air compressor based on the ratio between the inlet pressure of the fuel cell air system and the ambient pressure.

[0156] In a possible implementation, when the fuel cell air system is operating, the inlet pressure corresponding to the current request can be queried according to the current request of the fuel cell stack or the inlet pressure can be collected through a pressure gauge, and the ambient pressure of the fuel cell air system is measured. The ratio between the inlet pressure and the ambient pressure is determined as the compression ratio of the air compressor.

[0157] S1002. Determine the surge control flow rate based on the compression ratio of the air compressor and the surge control line.

[0158] Among them, the surge control line is used to represent the corresponding relationship between the compression ratio of the air compressor and the minimum flow threshold for the safe operation of the air compressor.

[0159] In a possible implementation, the surge control line corresponding to the current speed can be queried based on the current speed of the air compressor. Thus, the standard condition flow rate of the air compressor corresponding to the compression ratio of the air compressor is queried through the surge control line, which is the surge control flow rate.

[0160] It should be understood that through the compression ratio and the flow rate of the air compressor of the fuel cell air system at different air compressor speeds, the surge line of the air compressor can be accurately determined. The accuracy of the surge control line is improved, and the surge boundary of the air compressor is clarified. So as to more accurately control the bypass flow rate based on the surge boundary value of the air compressor.

[0161] The above mainly introduces the solution provided by the embodiments of the present application from the perspective of the method. To implement the above functions, the bypass flow rate control device or the vehicle includes the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, combining the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0162] Embodiments of the present application can, according to the above method, exemplarily divide the functional modules of the bypass flow control device or the vehicle. For example, the bypass flow control device or the vehicle may include respective functional modules corresponding to each functional division, or two or more functions may be integrated into one processing module. The above integrated module may be implemented in the form of hardware or in the form of a software functional module. It should be noted that the division of modules in the embodiments of the present application is illustrative, merely a logical functional division, and there may be other division methods in actual implementation.

[0163] Figure 11 is a block diagram of a bypass flow control device shown according to an exemplary embodiment. Referring to Figure 11 , the bypass flow control device 1100 includes: a determination module 1101 and a control module 1102.

[0164] The determination module 1101 is configured to, when the air compressor in the fuel cell air system is in a surge condition, determine a bypass flow request value based on the surge control flow of the air compressor and the flow into the stack; the surge control flow is the minimum flow threshold for the safe operation of the air compressor; the determination module 1101 is further configured to determine a feedforward value of the opening of the bypass valve of the fuel cell air system based on the bypass flow request value; the control module 1102 is configured to control the opening of the bypass valve based on the feedforward value of the opening to control the bypass flow of the fuel cell air system.

[0165] In a possible implementation manner, the determination module 1101 is specifically configured to determine the bypass flow standard condition value as the difference between the surge control flow and the flow into the stack; and convert the bypass flow standard condition value into the bypass flow request value under the current working condition of the fuel cell air system based on the ambient temperature and pressure of the fuel cell air system.

[0166] In a possible implementation manner, the determination module 1101 is specifically configured to determine the feedforward value of the opening of the bypass valve based on the bypass flow request value, the temperature into the stack, the pressure into the stack, and the ambient pressure.

[0167] In a possible implementation manner, the determination module 1101 is specifically configured to determine the functional correspondence relationship between the opening of the bypass valve and the pressure into the stack, the ambient pressure, the temperature into the stack, and the bypass flow request value based on the bypass valve flow calculation model; the bypass valve flow calculation model is used to characterize the quantitative relationship between the bypass flow of the fuel cell air system and the pressure and temperature; substitute the bypass flow request value, the temperature into the stack, the pressure into the stack, and the ambient pressure into the functional correspondence relationship to obtain the feedforward value of the opening of the bypass valve.

[0168] In a possible implementation, the control module 1102 is specifically configured to determine an opening compensation value of a bypass valve of the fuel cell air system based on a bypass flow request value; and control the opening of the bypass valve based on a feedforward opening value and the opening compensation value.

[0169] In a possible implementation, the control module 1102 is specifically configured to input the difference between the bypass flow request value and the actual bypass flow value into a PID controller to obtain an opening compensation value of the bypass valve.

[0170] In a possible implementation, the surge control flow is determined as follows: based on the ratio between the inlet pressure and the ambient pressure of the fuel cell air system, determine the pressure ratio of the air compressor; based on the pressure ratio of the air compressor and the surge control line, determine the surge control flow; the surge control line is used to characterize the corresponding relationship between the pressure ratio of the air compressor and the minimum flow threshold for the safe operation of the air compressor.

[0171] In a possible implementation, the above-mentioned bypass flow control device 1100 further includes: an acquisition module 1103. The acquisition module 1103 is configured to acquire the pressure ratio and the air flow of the air compressor of the fuel cell air system at different air compressor speeds; the determination module 1101 is further configured to determine the air compressor surge line based on the pressure ratio and the air flow of the air compressor of the fuel cell air system at different air compressor speeds; the air compressor surge line is used to characterize the corresponding relationship between the pressure ratio and the air flow of the air compressor when the fuel cell air system surges at different air compressor speeds; the determination module 1101 is further configured to determine the surge control line based on the air compressor surge line.

[0172] In a possible implementation, when the surge control flow is greater than the inlet flow, the air compressor of the fuel cell air system is in a surge condition.

[0173] According to the above technical means, the bypass flow request value is determined through the surge control flow to determine the feedforward opening of the bypass valve to adjust the opening of the bypass valve, increasing the air flow of the air compressor so that the gas flow entering the air compressor is not lower than the minimum safe operation volume threshold, so that the air compressor can get out of the surge condition. Moreover, the feedforward opening value of the bypass valve is used to predict the required opening of the bypass valve according to the bypass flow request value, so that the opening adjustment of the bypass valve can quickly respond to the change of the surge condition of the air compressor. The bypass flow can be quickly adjusted through the feedforward opening value, so that the air compressor can quickly resume stable operation.

[0174] Regarding the device in the above embodiments, the specific manners in which each module performs operations have been described in detail in the embodiments related to the method, and will not be elaborated here.

[0175] Figure 12 is a block diagram of a vehicle shown according to an exemplary embodiment. AsFigure 12 As shown, vehicle 1200 includes, but is not limited to, a processor 1201 and a memory 1202.

[0176] Among them, the above-mentioned memory 1202 is used to store executable instructions of the above-mentioned processor 1201. It can be understood that the above-mentioned processor 1201 is configured to execute instructions to implement the bypass flow method in the above-mentioned embodiments.

[0177] It should be noted that those skilled in the art can understand that Figure 12 the vehicle structure shown in does not constitute a limitation on the vehicle. The vehicle may include more or fewer components than Figure 12 shown, or combine certain components, or have different component arrangements.

[0178] The processor 1201 is the control center of the vehicle, connecting various parts of the entire vehicle through various interfaces and lines. By running or executing software programs and / or modules stored in the memory 1202, and calling data stored in the memory 1202, it executes various functions of the vehicle and processes data, thereby monitoring the vehicle as a whole. The processor 1201 may include one or more processing units. Optionally, the processor 1201 may integrate an application processor and a modem processor. Among them, the application processor mainly processes the operating system, user interface, application programs, etc., and the modem processor mainly processes wireless communication. It can be understood that the above-mentioned modem processor may not be integrated into the processor 1201 either.

[0179] The memory 1202 can be used to store software programs and various data. The memory 1202 mainly includes a program storage area and a data storage area. Among them, the program storage area can store the operating system, application programs required by at least one functional module (such as a determination unit, a processing unit, etc.), etc. In addition, the memory 1202 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage devices.

[0180] In an exemplary embodiment, a computer-readable storage medium including instructions is also provided, such as the memory 1202 including instructions. The above instructions can be executed by the processor 1201 of the vehicle 1200 to implement the bypass flow method in the above-mentioned embodiments.

[0181] In actual implementation, Figure 11 the functions of the determination module 1101, the control module 1102, and the acquisition module 1103 in can all be implemented by Figure 12 the processor 1201 in calling the computer program stored in the memory 1202. The specific execution process can refer to the description of the method part in the above embodiments and will not be elaborated here.

[0182] Optionally, the computer-readable storage medium may be a non-transitory computer-readable storage medium. For example, the non-transitory computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a CD-ROM, magnetic tape, a floppy disk, and an optical data storage device, etc.

[0183] In an exemplary embodiment, the embodiments of the present application further provide a computer program product including one or more instructions, and the one or more instructions may be executed by a processor 1201 of a vehicle to complete the bypass flow method in the above embodiments.

[0184] It should be noted that when the instructions in the above computer-readable storage medium or the one or more instructions in the computer program product are executed by the processor of the vehicle, each process of the above method embodiments is implemented, and the same technical effects as the above method can be achieved. To avoid repetition, it will not be elaborated here.

[0185] Through the description of the above embodiments, those skilled in the art can clearly understand that for the convenience and brevity of description, only the above division of each functional module is used as an example. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

[0186] In several embodiments provided by the present application, it should be understood that the disclosed device and method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other may be through some interfaces. The indirect coupling or communication connection of the device or unit may be in an electrical, mechanical or other form.

[0187] The units described as separate components may or may not be physically separated. The components displayed as units may be a physical unit or multiple physical units, that is, they may be located in one place, or may be distributed to multiple different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0188] In addition, in each embodiment of the present application, each functional unit can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0189] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiments of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions for causing a device (which can be a single-chip microcomputer, a chip, etc.) or a processor to execute all or part of the steps of the methods of the various embodiments of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical discs that can store program codes.

[0190] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A bypass flow control method, characterized in that: The bypass flow control method comprises: When the air compressor of the fuel cell air system is in a surge condition, a bypass flow request value is determined based on the surge control flow and the stack flow of the air compressor; the surge control flow is the minimum flow threshold for safe operation of the air compressor; when the surge control flow of the air compressor is greater than the stack flow, the bypass flow request value is used to request control of the bypass valve to increase the bypass flow of the fuel cell air system; Based on the bypass valve flow calculation model, determining the functional correspondence between the bypass valve opening and the stack inlet pressure, the ambient pressure, the stack inlet temperature and the bypass flow request value; the bypass valve flow calculation model is used to characterize the quantitative relationship between the bypass flow and the pressure and temperature of the fuel cell air system; Substituting the bypass flow request value, the stack entry temperature, the stack entry pressure, and the ambient pressure into the functional correspondence to obtain an opening feedforward value of the bypass valve; The function correspondence relationship satisfies the following formula: Among them, r and k are constants, The pile pressure, For environmental pressure, is the temperature of the pile, Request value for bypass flow, For bypass valve opening Function of Based on the opening feedforward value, the opening of the bypass valve is controlled to control the bypass flow of the fuel cell air system.

2. The bypass flow control method according to claim 1, characterized in that: The step of determining the bypass flow request value based on the surge control flow and the stack flow of the air compressor includes: Determine the difference between the surge control flow and the stack inlet flow as the bypass flow standard value; Based on the ambient temperature and pressure of the fuel cell air system, the bypass flow rate standard condition value is converted into a bypass flow rate request value under the current working condition of the fuel cell air system.

3. The bypass flow control method according to claim 1, characterized in that: The controlling the opening of the bypass valve based on the opening feedforward value comprises: determining an opening compensation value of a bypass valve of the fuel cell air system based on the bypass flow request value; The opening degree of the bypass valve is controlled based on the opening degree feedforward value and the opening degree compensation value.

4. The bypass flow control method according to claim 3, characterized in that: The step of determining an opening compensation value of a bypass valve of the fuel cell air system based on the bypass flow request value comprises: The difference between the bypass flow request value and the bypass flow actual value is input into a proportional integral differential PID controller to obtain an opening compensation value of the bypass valve.

5. The bypass flow control method according to any one of claims 1 to 4, characterized in that: The surge control flow is determined by: Determining the pressure ratio of the air compressor based on the ratio between the stack inlet pressure of the fuel cell air system and the ambient pressure; The surge control flow is determined based on the pressure ratio of the air compressor and a surge control line; the surge control line is used to characterize the corresponding relationship between the pressure ratio of the air compressor and the minimum flow threshold for safe operation of the air compressor.

6. The bypass flow control method according to claim 5, characterized in that: The method further comprises: Obtaining the air compressor pressure ratio and air compressor flow rate of the fuel cell air system at different air compressor speeds; Based on the air compressor pressure ratio and air compressor flow rate of the fuel cell air system at different air compressor speeds, an air compressor surge line is determined; the air compressor surge line is used to characterize the corresponding relationship between the air compressor pressure ratio and the air compressor flow rate when the fuel cell air system surges at different air compressor speeds; The surge control line is determined based on the air compressor surge line.

7. The bypass flow control method according to any one of claims 1 to 4, characterized in that: When the surge control flow is greater than the stack inflow flow, the air compressor of the fuel cell air system is in a surge condition.

8. A fuel cell air system, characterized in that: The fuel cell air system comprises: an air compressor, a bypass valve and a controller; The air compressor is used to compress the gas entering the air compressor; The bypass valve is used to control the bypass flow of the fuel cell air system; The controller is used to control the opening of the bypass valve based on the opening feedforward value and the opening compensation value of the bypass valve when the air compressor is in a surge condition, and adjust the gas flow passing through the bypass valve so that the air compressor is out of the surge condition; wherein the opening feedforward value of the bypass valve is determined based on the bypass flow request value, the stack entry temperature, the stack entry pressure, and the ambient pressure; the bypass flow request value is determined based on the surge control flow and the stack entry flow of the air compressor; the surge control flow is the minimum flow threshold for the safe operation of the air compressor; when the surge control flow of the air compressor is greater than the stack entry flow, the bypass flow request value is used to request the bypass valve to increase the bypass flow of the fuel cell air system; The opening feedforward value of the bypass valve is determined based on the bypass flow request value, the stack entry temperature, the stack entry pressure, the ambient pressure and a functional correspondence; the functional correspondence is a functional correspondence between the bypass valve opening and the stack entry pressure, the ambient pressure, the stack entry temperature and the bypass flow request value; the functional correspondence is determined based on a bypass valve flow calculation model, and the bypass valve flow calculation model is used to characterize the quantitative relationship between the bypass flow and the pressure and temperature of the fuel cell air system; The function correspondence relationship satisfies the following formula: Among them, r and k are constants, The pile pressure, For environmental pressure, is the temperature of the pile, Request value for bypass flow, For bypass valve opening function.

9. A bypass flow control device, characterized in that: The bypass flow control device comprises: a determination module and a control module; The determination module is used to determine the bypass flow request value based on the surge control flow and the stack flow of the air compressor when the air compressor of the fuel cell air system is in a surge condition; the surge control flow is the minimum flow threshold for the safe operation of the air compressor; when the surge control flow of the air compressor is greater than the stack flow, the bypass flow request value is used to request the bypass valve to increase the bypass flow of the fuel cell air system; The determination module is further used to determine the functional correspondence between the bypass valve opening and the stack inlet pressure, the ambient pressure, the stack inlet temperature and the bypass flow request value based on the bypass valve flow calculation model; the bypass valve flow calculation model is used to characterize the quantitative relationship between the bypass flow and the pressure and temperature of the fuel cell air system; the bypass flow request value, the stack inlet temperature, the stack inlet pressure and the ambient pressure are substituted into the functional correspondence to obtain the bypass valve opening feedforward value; The function correspondence relationship satisfies the following formula: Among them, r and k are constants, The pile pressure, For environmental pressure, is the temperature of the pile, Request value for bypass flow, For bypass valve opening Function of The control module is used to control the opening of the bypass valve based on the opening feedforward value to control the bypass flow of the fuel cell air system.

10. A vehicle, characterized in that: The vehicle comprises: processor; a memory for storing instructions executable by the processor; The processor is configured to execute the instructions to implement the bypass flow control method according to any one of claims 1 to 7.

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