Method, device, equipment and medium for estimating circulating flow rate of cooling loop of fuel cell system

Abstract

The present application discloses a method, device, equipment and medium for estimating the circulating flow rate of a cooling circuit of a fuel cell system, which relates to the technical field of fuel cell temperature control. The present application first constructs a first relationship curve, a second relationship curve and a third relationship curve, and then estimates the total flow rate based on the pressure difference between the inlet and outlet of the cooling circuit or estimates the total flow rate based on the rotational speed of the cooling water pump and the opening degree of the three-way valve in the cooling circuit, and further estimates the large-circulation flow rate and the small-circulation flow rate in combination with the opening degree of the three-way valve, realizing the estimation of the large and small circulation flow rates without installing a flow meter.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cell temperature control, and particularly to a method, device, equipment and medium for estimating the circulating flow rate of a cooling circuit of a fuel cell system. Background Art

[0002] In recent years, energy and environmental issues have received extensive attention from society. Fuel cells have become a current research hotspot due to their advantages such as high efficiency, pollution-free, and renewable energy sources.

[0003] While generating electrical energy through electrochemical reactions, a fuel cell system also generates heat. If reasonable temperature control is not carried out during operation, problems such as abnormal water content state inside the stack and reduced catalyst activity will occur, affecting the stability and efficiency of the system. In extreme cases, it may damage system components and shorten the system life. Therefore, how to perform fast and accurate temperature control on a fuel cell system is a key issue in the field of system integrated control. Traditional temperature control usually uses the PID algorithm, but this method has poor environmental adaptability and it is difficult to achieve good control effects in different environments. To further optimize the temperature control strategy, a cooling circuit model can be constructed based on the principles of thermodynamics and heat transfer to achieve faster and more accurate control. In the model-based control algorithm, the coolant flow rate is a key data. However, due to cost limitations, flow meters are rarely installed in the system cooling circuit, and it is difficult to accurately estimate the coolant flow rates of the large and small cycles in the cooling circuit, which also limits the application of this control method. Summary of the Invention

[0004] The purpose of the present application is to provide a method, device, equipment and medium for estimating the circulating flow rate of a cooling circuit of a fuel cell system, which can accurately estimate the coolant flow rates of the large and small cycles in the cooling circuit under the condition that no flow meter is installed in the cooling circuit.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] In the first aspect, the present application provides a method for estimating the circulating flow rate of a cooling circuit of a fuel cell system, and the circulating flow rate estimation method includes:

[0007] Construct a first relationship curve, a second relationship curve, and a third relationship curve; the first relationship curve is used to characterize the relationship between the pressure difference between the inlet and outlet of the cooling circuit and the total flow rate of the cooling circuit, the second relationship curve is used to characterize the relationship between the rotational speed of the cooling water pump in the cooling circuit, the opening degree of the three-way valve in the cooling circuit, and the total flow rate of the cooling circuit, and the third relationship curve is used to characterize the relationship between the large-circulation flow area, the small-circulation flow area in the cooling circuit, and the opening degree of the three-way valve;

[0008] Estimate the total flow rate of the cooling circuit based on the first relationship curve and / or the second relationship curve to obtain an estimated value of the total flow rate;

[0009] Calculate the estimated value of the large-loop flow rate and the estimated value of the small-loop flow rate according to the estimated value of the total flow rate and the third relationship curve.

[0010] In a second aspect, a device for estimating the circulating flow rate of a fuel cell system cooling circuit, the device for estimating the circulating flow rate applying the above method for estimating the circulating flow rate of a cooling circuit, the device for estimating the circulating flow rate comprising:

[0011] A relationship curve acquisition module, configured to construct a first relationship curve, a second relationship curve, and a third relationship curve; the first relationship curve is used to characterize the relationship between the pressure difference between the inlet and outlet of the cooling circuit and the total flow rate of the cooling circuit, the second relationship curve is used to characterize the relationship between the rotational speed of the cooling water pump in the cooling circuit, the opening degree of the three-way valve in the cooling circuit, and the total flow rate of the cooling circuit, and the third relationship curve is used to characterize the relationship between the large-loop flow area, the small-loop flow area in the cooling circuit, and the opening degree of the three-way valve;

[0012] A total flow rate estimation module, configured to estimate the total flow rate of the cooling circuit based on the first relationship curve and / or the second relationship curve to obtain an estimated value of the total flow rate;

[0013] A large and small loop flow rate estimation module, configured to calculate the estimated value of the large-loop flow rate and the estimated value of the small-loop flow rate according to the estimated value of the total flow rate and the third relationship curve.

[0014] In a third aspect, a computer device includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor executes the computer program to implement the above method for estimating the circulating flow rate of a fuel cell system cooling circuit.

[0015] In a fourth aspect, a computer-readable storage medium stores a computer program thereon, and when the computer program is executed by a processor, it implements the above method for estimating the circulating flow rate of a fuel cell system cooling circuit.

[0016] According to the specific embodiments provided in the present application, the present application discloses the following technical effects:

[0017] The present application provides a method, device, equipment and medium for estimating the circulating flow rate of a cooling loop of a fuel cell system. The present application first constructs a first relationship curve, a second relationship curve and a third relationship curve, and then estimates the total flow rate based on the pressure difference between the inlet and outlet of the cooling loop or estimates the total flow rate based on the rotational speed of the cooling water pump and the opening degree of the three-way valve in the cooling loop, and further estimates the large-circulation flow rate and the small-circulation flow rate in combination with the opening degree of the three-way valve, realizing the estimation of the large and small circulation flow rates without installing a flow meter.

[0018] When the fuel cell system is in a steady state, the estimated values of the total flow rate, the large-circulation flow rate and the small-circulation flow rate estimated by temperature are corrected, which can prevent the phenomenon of inaccurate flow rate estimation caused by changes in the performance of the water pump and the flow resistance of the flow channel, and improve the accuracy. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is an application environment diagram of a method for estimating the circulating flow rate of a cooling loop of a fuel cell system according to an embodiment of the present application;

[0021] Figure 2 It is a flowchart of a method for estimating the circulating flow rate of a cooling loop of a fuel cell system provided by an embodiment of the present application;

[0022] Figure 3 It is a schematic structural diagram of a cooling loop provided by an embodiment of the present application;

[0023] Figure 4 It is a data calibration flowchart provided by an embodiment of the present application;

[0024] Figure 5 It is a relationship curve diagram between the pressure difference between the inlet and outlet of a cooling loop and the total flow rate provided by an embodiment of the present application;

[0025] Figure 6 It is a relationship curve diagram between the rotational speed of a cooling water pump, the opening degree of a three-way valve and the flow rate in a cooling loop provided by an embodiment of the present application;

[0026] Figure 7 It is a relationship curve diagram between the flow area of a three-way valve and the opening degree of the three-way valve provided by an embodiment of the present application;

[0027] Figure 8 It is a flowchart of online flow rate estimation provided by an embodiment of the present application;

[0028] Figure 9 The structural schematic diagram of a computer device provided by an embodiment of the present application. Specific implementation manners

[0029] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present application.

[0030] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0031] The method for estimating the circulation flow rate of the cooling loop of the fuel cell system provided by the embodiment of the present application can be applied to an application environment as Figure 1 shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set separately, integrated on the server 104, placed in the cloud or on other servers. The terminal 102 can send the pressure difference between the inlet and outlet of the cooling loop, the rotational speed of the cooling water pump, and the opening degree of the three-way valve to the server 104. After receiving the pressure difference between the inlet and outlet of the cooling loop, the rotational speed of the cooling water pump, and the opening degree of the three-way valve, the server 104 estimates the total flow rate of the cooling loop according to the first relationship curve and / or the second relationship curve to obtain the total flow rate estimation value; according to the total flow rate estimation value and the third relationship curve, calculate the large circulation flow rate estimation value and the small circulation flow rate estimation value. The server 104 can feedback the obtained large circulation flow rate estimation value and small circulation flow rate estimation value to the terminal 102. In addition, in some embodiments, the method for estimating the circulation flow rate of the cooling loop of the fuel cell system can also be implemented by the server 104 or the terminal 102 alone. For example, the terminal 102 can directly process the pressure difference between the inlet and outlet of the cooling loop, the rotational speed of the cooling water pump, and the opening degree of the three-way valve, or the server 104 can obtain the pressure difference between the inlet and outlet of the cooling loop, the rotational speed of the cooling water pump, and the opening degree of the three-way valve from the data storage system and process the pressure difference between the inlet and outlet of the cooling loop, the rotational speed of the cooling water pump, and the opening degree of the three-way valve.

[0032] Among them, the terminal 102 can be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, Internet of Things devices, and portable wearable devices. The Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart in-vehicle devices, etc. The portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers, and can also be a cloud server.

[0033] In an exemplary embodiment, as Figure 2 shown, a method for estimating the circulating flow rate of a fuel cell system cooling circuit is provided. This method is executed by a computer device, specifically, it can be executed alone by a computer device such as a terminal or a server, or jointly executed by a terminal and a server. In the embodiments of the present application, taking this method applied to Figure 1 the server 104 in it as an example for illustration, it includes the following steps 201 to step 203. Among them:

[0034] Step 201, construct a first relationship curve, a second relationship curve, and a third relationship curve; the first relationship curve is used to characterize the relationship between the pressure difference between the inlet and outlet of the cooling circuit and the total flow rate of the cooling circuit, the second relationship curve is used to characterize the relationship between the rotational speed of the cooling water pump in the cooling circuit, the opening degree of the three-way valve in the cooling circuit, and the total flow rate of the cooling circuit, and the third relationship curve is used to characterize the relationship between the large-circulation flow area, the small-circulation flow area in the cooling circuit, and the opening degree of the three-way valve.

[0035] Step 202, estimate the total flow rate of the cooling circuit according to the first relationship curve and / or the second relationship curve to obtain an estimated total flow rate value.

[0036] Step 203, calculate the estimated large-circulation flow rate value and the estimated small-circulation flow rate value according to the estimated total flow rate value and the third relationship curve.

[0037] Implementing the above steps 201 to 203 can realize the prediction of the large and small circulation flow rates without installing a flow meter.

[0038] In the above embodiment, the structure of the cooling circuit of the fuel cell system is as Figure 3 shown, including: the fuel cell system stack 1, the cooling water pump 2, the PTC heater 3, the three-way valve 4, the cooling fan 5, the water outlet pressure sensor 6, the water outlet temperature sensor 7, the water inlet temperature sensor 8, the water inlet pressure sensor 9. Among them, the circulation flowing through the PTC heater 3 is the small circulation, and the circulation flowing through the cooling fan 5 is the large circulation.

[0039] In another exemplary embodiment of the present application, in order to construct the first relationship curve, the second relationship curve, and the third relationship curve, asFigure 4 As shown, the above step 201 is replaced by the following steps 301 to 303:

[0040] Step 301: On the fuel cell stack test bench, collect the pressure difference between the inlet and outlet and the total flow rate of the cooling circuit, and fit the first relationship curve based on the pressure difference between the inlet and outlet and the total flow rate of the cooling circuit.

[0041] In step 301, it is necessary to collect the pressure difference between the inlet and outlet and the inlet and outlet flow rate (i.e., the total flow rate) of the cooling circuit on the fuel cell stack test bench, and fit the relationship curve between the inlet and outlet pressure difference and the total flow rate to obtain the first relationship curve, as Figure 5 shown.

[0042] Furthermore, the fuel cell stack test bench is a device for testing the performance of fuel cell stacks.

[0043] Step 302: On the fuel cell system test bench, measure the pressure difference between the inlet and outlet of the cooling circuit at different cooling water pump speeds and different three-way valve openings.

[0044] Step 303: According to the pressure difference between the inlet and outlet of the cooling circuit at different cooling water pump speeds and different three-way valve openings, use the first relationship curve to calculate the total flow rate of the cooling circuit at different cooling water pump speeds and different three-way valve openings.

[0045] Step 304: Fit the second relationship curve based on the total flow rate of the cooling circuit at different cooling water pump speeds and different three-way valve openings.

[0046] In steps 302 to 304, it is necessary to calibrate the relationship between the cooling water pump speed, the three-way valve opening and the total flow rate on the fuel cell system test bench based on different cooling water pump speeds and different three-way valve openings, including the following steps:

[0047] S21: Keep the cooling water pump speed constant and gradually increase the opening of the three-way valve.

[0048] S22: Collect the pressure difference between the inlet and outlet of the cooling circuit and estimate the total flow rate based on the first relationship curve fitted in step 301.

[0049] S23: Adjust the cooling water pump speed and repeat S21 and S22.

[0050] S24: Based on the data collected and calculated in S22, fit the relationship curve between the cooling water pump speed, the three-way valve opening and the total flow rate, that is, the second relationship curve, as Figure 6 shown.

[0051] Further, the rotational speeds of different cooling water pumps can adopt the rotational speeds corresponding to the performance curves in the performance curve graph of the water pump, and this performance curve is usually provided by the water pump manufacturer. The typical rotational speeds of the water pump in this example are: 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, 5500 rpm, 6000 rpm.

[0052] Further, different opening degrees of the three-way valve refer to: increasing the opening degree of the three-way valve at equal intervals. The smaller the angular interval, the more accurate the relationship curve fitted by the test data. The typical opening degrees adopted by the three-way valve are: 0%, 25%, 50%, 75%, 100%. When testing the data, increase the rotational speed of the cooling water pump and the opening degree of the three-way valve in sequence.

[0053] Further, the fuel cell system test bench is a device for testing and researching the performance of the fuel cell system.

[0054] Step 305, construct the third relationship curve according to the technical parameters of the three-way valve, as Figure 7 shown.

[0055] In another exemplary embodiment of the present application, in order to obtain the estimated value of the large circulation flow rate and the estimated value of the small circulation flow rate, as Figure 8 shown, then the above steps 202 and 203 are replaced by the following steps S31 to S33:

[0056] S31: When the detection of the inlet and outlet pressures of the cooling circuit is effective, based on the first relationship curve fitted in step 301, by collecting the pressure difference between the inlet and outlet of the cooling circuit, estimate the total flow rate to obtain the estimated value L of the total flow rate sum .

[0057] S32: When the detection of the inlet and outlet pressures of the cooling circuit fails, based on the second relationship curve fitted in 304, estimate the total flow rate through the rotational speed of the cooling water pump and the opening degree of the three-way valve to obtain the estimated value L of the total flow rate sum .

[0058] S33: Assume that the flow velocity of the coolant flowing out of the three-way valve in the same system is the same, and the coolant flow rates of the large and small circulations are proportional to the cross-sectional area of the three-way valve. Based on the relationship curve between the opening degree of the three-way valve and the cross-sectional area (i.e., the third relationship curve), estimate the coolant flow rates of the large and small circulations to obtain the estimated values L of the large and small circulation flow rates ex and L in .

[0059] Further, the method for estimating the total flow rate through the second relationship curve is as follows:

[0060] Refer to Figure 6, select any operating point. In this example, the operating point with a cooling water pump speed of 3500 rpm and a three-way valve opening of 40% is selected for verification. Based on the pump speed, the curve corresponding to 3500 rpm is between r2 and r3, and based on the three-way valve opening, the curve corresponding to 40% opening is between v2 and v3. According to the size difference between the verification operating point and the two standard operating points, determine the approximate curve range of the verification operating point. The abscissa of the intersection point of the two curves is the flow rate a L / min under this verification condition. Further, the relationship curve between the flow area of the three-way valve and the valve opening is usually provided by the manufacturer, such as Figure 7 shown, the relationship formula between the coolant flow rate and the flow area is: where L w is the coolant flow rate, U w is the coolant flow velocity, and A is the flow area.

[0061] L w = U w * A;

[0062] Therefore, in the same system, the coolant flow rates of the large and small cycles are proportional to the cross-sectional area of the three-way valve. The relationship formula between the three-way valve opening and the coolant flow rate entering the large and small cycles is: where A ex is the flow area of the large cycle, A in is the flow area of the small cycle, and A W is the total flow area.

[0063]

[0064] Furthermore, when the fuel cell system is in a steady-state operating condition, the estimated values of the large and small cycle flow rates can be further corrected to further improve the accuracy of the flow rate estimation.

[0065] The fuel cell system being in a steady-state operating condition means that the fuel cell system operates at a constant power, and the temperatures at the inlet and outlet of the stack basically remain unchanged, that is: the power change of the fuel cell system ≤ ±2%, the temperature change at the inlet and outlet of the cooling circuit ≤ ±2°C, and the operating time satisfying the above conditions ≥ 5 s, then it can be determined that the system is in a steady-state operating condition. Calculate the flow rate based on the temperature rise and correct the calibration data in the database, including the following steps:

[0066] S41: When the detection of the coolant temperatures at the inlet and outlet of the cooling circuit is valid, collect the coolant temperatures at the inlet and outlet of the cooling circuit and calculate the total flow rate L sum,t .

[0067] S42: When the detection of the cooling temperatures at the inlet and outlet of the PTC heater is valid, collect the coolant temperatures at the inlet and outlet of the PTC heater and calculate the small cycle flow rate L in,t .

[0068] S43: Based on the calculated flow rates L sum,t 、Lin,t and the estimated flow rate L sum , L in Output the error and correct the data between differential pressure - flow rate, rotational speed, opening degree and flow rate in the database.

[0069] Furthermore, based on data such as the operating current of the stack, the voltage of a single cell, and the number of single cells, calculate the heat generation of the stack under this operating condition. The heat generation power calculation formula is as follows:

[0070] Q stk = N * I * (E - U);

[0071] Where, Q stk is the heat generation of the stack, N is the number of single cells contained in the stack, I is the current passing through the stack, and E and U are the thermal equilibrium potential of hydrogen and the actual working voltage respectively.

[0072] Furthermore, when the fuel cell system is in a steady state, the inlet and outlet temperatures of the cooling circuit of the fuel cell system tend to be stable, and the heat generation of the stack is equal to the heat dissipation of the cooling system, that is, Q stk = Q w , where: Q w is the heat dissipation of the cooling circuit.

[0073] Furthermore, the formula for calculating the total flow rate based on the heat dissipation is: Q w = C w * L sum,t (T wout - T win ).

[0074] Where: Q w is the heat dissipation of the cooling circuit, C w is the specific heat capacity of the coolant in the cooling circuit, L sum,t is the total flow rate of the cooling circuit, T wout and T win are the outlet coolant temperature and the inlet coolant temperature of the cooling circuit respectively.

[0075] Similarly, the system small - cycle flow rate L in,t can be calculated.

[0076] Furthermore, the judgment basis for correction is:

[0077] |L sum - L sum,t |> 10% L sum ;

[0078] Or:

[0079] |L in - L in,t |> 10% L in;

[0080] If any of the above conditions is met, the calibration data in the database needs to be corrected.

[0081] Furthermore, the correction method is as follows: Based on L sum,t 、L in,t Replace the estimated L sum 、L in corresponding values under the current working condition.

[0082] When the system load power and the inlet and outlet temperatures of the cooling circuit remain basically unchanged and continue for a period of time, the estimated flow value will be replaced by the flow value calculated based on the temperature rise, because the system flow can be calculated more accurately through the temperature rise. If the detected values of the inlet and outlet temperatures of the stack cooling circuit are invalid, the system flow still adopts the estimation method. Similarly, the flow calculated based on the temperature rise at the inlet and outlet of the PTC heater is also the same.

[0083] In the embodiments of the present application, the calculated flow is compared with the estimated flow. When the difference between the two is too large. It indicates that due to long-term operation of the system or other external reasons, the internal flow resistance of the system has changed greatly compared with the calibration time. Continuing to use the data at the calibration time to estimate the system coolant flow will no longer be accurate. At this time, it is necessary to use the coolant flow data accurately calculated based on the temperature rise to update the calibration data to increase the accuracy and reliability of the system flow estimation strategy.

[0084] The estimation method in the embodiments of the present application has the following technical effects:

[0085] (1) By collecting the data between the flow rate, rotational speed and opening degree in the system test bench (stack test bench and fuel cell system test bench), fitting the relationship curve between the rotational speed of the cooling water pump, the opening degree of the three-way valve and the flow rate, and estimating the system flow based on the rotational speed of the cooling water pump and the opening degree of the three-way valve during system operation. Compared with the existing system flow measurement method, this flow estimation strategy can estimate the system flow without installing a flow meter, which can save project costs. Without installing a coolant flow meter, the coolant flow in the system can be estimated by measuring common temperature and pressure data.

[0086] (2) When the system sensor fails and the system flow cannot be directly measured or the system flow is estimated using the pressure difference, the relationship curve between the opening degree, rotational speed and flow rate of the present invention can be used for system flow estimation. The reliability is improved.

[0087] (3) After the system flow resistance changes due to long-term operation of the system or external reasons, this flow estimation strategy can automatically correct the estimation strategy when the system is in a steady state, so that the flow estimation strategy remains accurate and further improves the accuracy.

[0088] In an exemplary embodiment, a device for estimating the circulating flow rate of a fuel cell system cooling circuit includes:

[0089] A relationship curve acquisition module for constructing a first relationship curve, a second relationship curve, and a third relationship curve; the first relationship curve is used to characterize the relationship between the pressure difference between the inlet and outlet of the cooling circuit and the total flow rate of the cooling circuit, the second relationship curve is used to characterize the relationship between the rotational speed of the cooling water pump in the cooling circuit, the opening degree of the three-way valve in the cooling circuit, and the total flow rate of the cooling circuit, and the third relationship curve is used to characterize the relationship between the large-circulation flow area, the small-circulation flow area in the cooling circuit, and the opening degree of the three-way valve.

[0090] A total flow rate estimation module for estimating the total flow rate of the cooling circuit according to the first relationship curve and / or the second relationship curve to obtain a total flow rate estimation value.

[0091] A large- and small-circulation flow rate estimation module for calculating a large-circulation flow rate estimation value and a small-circulation flow rate estimation value according to the total flow rate estimation value and the third relationship curve.

[0092] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as shown in Figure 9 The figure shows. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data for complementary determination. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, it implements a method for estimating the circulating flow rate of a fuel cell system cooling circuit.

[0093] Those skilled in the art can understand that Figure 9 the structure shown in the figure is only a block diagram of some structures related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0094] In an exemplary embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the steps in the embodiment of the above-mentioned method for estimating the circulating flow rate of the fuel cell system cooling circuit are implemented.

[0095] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the steps in the embodiment of the above-mentioned method for estimating the circulating flow rate of the fuel cell system cooling circuit are implemented.

[0096] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the various embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0097] The databases involved in the various embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the various embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, etc., without limitation.

[0098] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0099] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation on the present application.

Claims

1. A method for estimating the circulation flow rate of a cooling circuit of a fuel cell system, characterized in that: The method for estimating the circulation flow of the cooling circuit of the fuel cell system comprises: Constructing a first relationship curve, a second relationship curve and a third relationship curve; the first relationship curve is used to characterize the relationship between the inlet and outlet pressure difference of the cooling circuit and the total flow of the cooling circuit, the second relationship curve is used to characterize the relationship between the cooling water pump speed in the cooling circuit, the three-way valve opening in the cooling circuit and the total flow of the cooling circuit, and the third relationship curve is used to characterize the relationship between the large circulation flow area, the small circulation flow area and the three-way valve opening in the cooling circuit; estimating a total flow of the cooling circuit according to the first relationship curve and / or the second relationship curve to obtain a total flow estimation value; Calculating a large circulation flow estimate and a small circulation flow estimate according to the total flow estimate and the third relationship curve; Constructing a first relationship curve, a second relationship curve, and a third relationship curve specifically includes: On the fuel cell test bench, collecting the inlet and outlet pressure difference and the total flow rate of the cooling circuit, and fitting the first relationship curve based on the inlet and outlet pressure difference and the total flow rate of the cooling circuit; On the fuel cell system bench, collect the inlet and outlet pressure difference of the cooling circuit at different cooling water pump speeds and different three-way valve openings; According to the inlet and outlet pressure differences of the cooling circuit at different cooling water pump speeds and different three-way valve openings, the total flow of the cooling circuit at different cooling water pump speeds and different three-way valve openings is calculated using the first relationship curve; The second relationship curve is fitted according to the total flow of the cooling circuit under different cooling water pump speeds and different three-way valve openings; Constructing the third relationship curve according to the technical parameters of the three-way valve; According to the total flow estimation value and the third relationship curve, a large circulation flow estimation value and a small circulation flow estimation value are calculated, and then the method further includes: Determining whether the fuel cell system is in a steady-state operating condition to obtain a second determination result; If the second judgment result is yes, the total flow of the cooling circuit is calculated according to the inlet coolant temperature, the outlet coolant temperature and the heat dissipation of the cooling circuit, and the total flow calculation value is obtained; the small circulation flow is calculated according to the inlet coolant temperature, the outlet coolant temperature and the heating amount of the PTC heater in the cooling circuit, and the small circulation flow calculation value is obtained; According to the total flow calculation value, the small circulation flow calculation value, the total flow estimation value and the small circulation flow estimation value, whether the correction condition is met is determined to obtain a third determination result; If the third judgment result is yes, the total flow estimation value is corrected to the total flow calculation value, the small circulation flow estimation value is corrected to the small circulation flow calculation value, and the large circulation flow estimation value is corrected to the difference between the total flow calculation value and the small circulation flow calculation value; If the second judgment result is no or the third judgment result is no, the total flow estimation value, the small circulation flow estimation value and the large circulation flow estimation value are not corrected.

2. The method for estimating the circulation flow rate of a fuel cell system cooling circuit according to claim 1, characterized in that: Estimating the total flow of the cooling circuit according to the first relationship curve and / or the second relationship curve to obtain a total flow estimation value specifically includes: Determine whether the fuel cell system meets the detection condition of the inlet and outlet pressure difference of the cooling circuit, and obtain a first determination result; If the first judgment result is yes, the inlet and outlet pressure difference of the cooling circuit is collected, and the total flow estimation value is obtained by using the first relationship curve according to the inlet and outlet pressure difference of the cooling circuit; If the first judgment result is no, then the total flow estimation value is obtained using the second relationship curve according to the cooling water pump speed and the three-way valve opening in the cooling circuit.

3. The method for estimating the circulation flow rate of a fuel cell system cooling circuit according to claim 1, characterized in that: Calculating a large circulation flow estimate and a small circulation flow estimate according to the total flow estimate and the third relationship curve, specifically comprising: Calculating the large circulation flow area and the small circulation flow area according to the opening of the three-way valve in the cooling circuit using the third relationship curve; According to the total flow estimate, the large circulation flow area and the small circulation flow area, the large circulation flow estimate and the small circulation flow estimate are calculated using the following formula; Among them, L ex and L in are the estimated values ​​of large circulation flow and small circulation flow respectively, A ex and A in are the large circulation area and the small circulation area, A W is the total flow area of ​​the three-way valve, L sum Estimated total flow.

4. The method for estimating the circulation flow rate of a fuel cell system cooling circuit according to claim 1, characterized in that: The condition that the fuel cell system is in a steady-state operating condition is that the continuous operation time of the fuel cell system under the preset operating condition is not less than the preset time; The preset operating condition is that the absolute value of the power change of the fuel cell system is not greater than the power change threshold, and the absolute values ​​of the inlet temperature change and the outlet temperature change of the cooling circuit are both not greater than the temperature change threshold; The correction conditions are: The absolute value of the difference between the total flow estimation value and the total flow calculation value is greater than the total flow estimation error threshold, or the absolute value of the difference between the small circulation flow estimation value and the small circulation flow calculation value is greater than the small circulation flow estimation error threshold.

5. The method for estimating the circulation flow rate of a fuel cell system cooling circuit according to claim 1, characterized in that: The formula for calculating the total flow rate of the cooling circuit is: Q w =C w *L sum,t (T wout -T win ); Among them, Q w is the heat dissipation of the cooling circuit, C w is the specific heat capacity of the coolant in the cooling circuit, L sum,t is the total flow rate of the cooling circuit, T wout and T win are the outlet coolant temperature and inlet coolant temperature of the cooling circuit respectively; The formula for calculating the small circulation flow is: Q in =C w *L in,t (T in-out -T in-in ); Among them, Q in is the heating capacity of the PTC heater, L in,t is the small circulation flow rate, T in-out and T in-in They are the outlet coolant temperature and inlet coolant temperature of the PTC heater respectively.

6. A circulation flow estimation device for a fuel cell system cooling circuit, characterized in that: The circulation flow estimation device applies the circulation flow estimation method according to any one of claims 1 to 5, and the circulation flow estimation device comprises: A relationship curve acquisition module is used to construct a first relationship curve, a second relationship curve and a third relationship curve; the first relationship curve is used to characterize the relationship between the inlet and outlet pressure difference of the cooling circuit and the total flow of the cooling circuit, the second relationship curve is used to characterize the relationship between the cooling water pump speed in the cooling circuit, the three-way valve opening in the cooling circuit and the total flow of the cooling circuit, and the third relationship curve is used to characterize the relationship between the large circulation flow area, the small circulation flow area and the three-way valve opening in the cooling circuit; a total flow estimation module, configured to estimate the total flow of the cooling circuit according to the first relationship curve and / or the second relationship curve to obtain a total flow estimation value; The large and small circulation flow estimation module is used to calculate the large circulation flow estimation value and the small circulation flow estimation value according to the total flow estimation value and the third relationship curve.

7. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a circulation flow estimation method for a cooling circuit of a fuel cell system according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the circulation flow estimation method of the cooling circuit of the fuel cell system according to any one of claims 1 to 5 is implemented.

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