Temperature control method of fuel cell system and fuel cell system

Abstract

The invention provides a temperature control method of a fuel cell system and the fuel cell system. The temperature control method comprises the following steps that a processor is used for executing the following processing: a pile cooling liquid outlet temperature correction value is determined according to a pile cooling liquid outlet temperature target value and a first related parameter, and a pile heat transfer model and a pump model are used for determining a target value of the rotating speed of a pump; determining a pile cooling liquid inlet temperature correction value according to the pile cooling liquid inlet temperature target value and the second associated parameter, and determining a three-way valve opening target value by using a three-way valve heat transfer model and a three-way valve flow model; determining a radiator outlet cooling liquid temperature correction value according to the radiator outlet cooling liquid temperature target value and the third correlation parameter, and calculating a fan rotating speed target value by using a radiator heat transfer model and a fan flow model; and adjusting the rotating speed of the pump, the opening degree of the three-way valve and the rotating speed of the fan according to each target value to realize synchronous adjustment of the working temperature of the fuel cell system.

Description

Technical Field

[0001] This application belongs to the technical field of temperature control, and particularly relates to a temperature control method for a fuel cell system and a fuel cell system. Background Art

[0002] In a fuel cell, the function of the cooling system is to maintain the operating temperature of the stack. Temperature affects the durability of the stack and the consistency of the single-piece state. Therefore, the response speed and accuracy of its control are important indicators. The main components of the cooling system include a water pump, a three-way valve, and a fan. The water pump is used to maintain the circulation of the coolant, the three-way valve is used to realize the conversion between the large circulation and the small circulation. Here, the large circulation means that the coolant flows through the radiator and returns to the stack, and the fan is used to cool the coolant flowing through the radiator. There is a coupling relationship among the temperatures at the inlet and outlet of the stack coolant and the outlet of the radiator. When the operating point of any one of the water pump, the three-way valve, and the fan changes, the above three temperatures will change and then reach a new stable point. The cooling system needs to be robust to cope with the interference caused by the change of the external environment of the fuel cell and the aging of components.

[0003] Existing cooling systems and their temperature control methods usually target a single temperature. For example, only the inlet or outlet temperature of the stack is controlled. Controlling only one of the inlet, outlet, and other temperatures of the stack cannot ensure that the fuel cell is stably maintained at the target temperature, resulting in the fuel cell operating under fluctuating temperature conditions. At the same time, the implementation method usually uses an open-loop calibrated MAP, which requires a large number of calibration tests during the development process. And because closed-loop control and physical models are not used, it cannot cope with the interference caused by the change of the external environment and the aging of components during use. Summary of the Invention

[0004] In view of the above problems, this application is proposed to solve the above problems existing in the prior art.

[0005] The purpose of this application is to provide a temperature control method for a fuel cell system and a fuel cell system according to the present invention, which can make the temperatures at the inlet and outlet of the stack and the outlet of the radiator synchronously approach the target values, thereby ensuring that the fuel cell is stably maintained at the target temperature; a large number of calibration tests can be omitted, accelerating the development; and it can cope with the interference caused by the change of the external environment and the aging of components.

[0006] According to a first aspect of the present disclosure, a method for controlling the temperature of a fuel cell system is provided. The fuel cell system includes a stack, a three-way valve, a radiator, a fan, and a pump. The coolant from the outlet of the pump is fed to the stack, and after flowing through the stack, the coolant is fed to the inlet of the three-way valve. The first outlet of the three-way valve is communicated with the inlet of the radiator, and the second outlet is communicated with the outlet of the radiator and the inlet of the pump. The fan is used to cool the coolant flowing through the radiator. The temperature control method includes the following processes executed by a processor: determining a correction value of the temperature of the coolant outlet of the stack according to a target value of the temperature of the coolant outlet of the stack and its first associated parameter; determining a target value of the total coolant flow rate by using a stack heat transfer model according to the correction value of the temperature of the coolant outlet of the stack; determining a target value of the rotational speed of the pump by using a pump model according to the determined target value of the total coolant flow rate; determining a correction value of the temperature of the coolant inlet of the stack according to a target value of the temperature of the coolant inlet of the stack and its second associated parameter; determining target values of the small-circulation flow rate and the large-circulation flow rate of the coolant by using a three-way valve heat transfer model according to the target value of the total coolant flow rate and the correction value of the temperature of the coolant inlet of the stack; determining a target value of the opening degree of the three-way valve by using a three-way valve flow model according to the target values of the small-circulation flow rate and the large-circulation flow rate of the coolant; determining a correction value of the temperature of the coolant at the outlet of the radiator according to a target value of the temperature of the coolant at the outlet of the radiator and its third associated parameter; determining a target value of the air flow rate of the radiator by using a radiator heat transfer model according to the correction value of the temperature of the coolant at the outlet of the radiator, the target value of the large-circulation flow rate of the coolant, the measured value of the temperature of the coolant at the inlet of the radiator, and the measured value of the air temperature; calculating a target value of the rotational speed of the fan by using a fan flow model according to the target value of the air flow rate of the radiator; and adjusting the rotational speed of the pump, the opening degree of the three-way valve, and the rotational speed of the fan according to the target value of the rotational speed of the pump, the target value of the opening degree of the three-way valve, and the target value of the rotational speed of the fan.

[0007] According to a second aspect of the present application, a fuel cell system is provided. The system includes a stack, a three-way valve, a radiator, a fan, a pump, and a processor. The coolant from the outlet of the pump is fed to the stack, and after flowing through the stack, the coolant is fed to the inlet of the three-way valve. The first outlet of the three-way valve is communicated with the inlet of the radiator, and the second outlet is communicated with the outlet of the radiator and the inlet of the pump. The fan is used to cool the coolant flowing through the radiator, and the processor is configured to execute the temperature control method of the fuel cell system according to various embodiments of the present application.

[0008] The temperature control method of the fuel cell system of the present application calculates the correction value by using the target value and the measured value of the temperature such as the temperature at the coolant outlet of the stack, so as to calculate the correction value of the temperature such as the temperature at the coolant outlet of the stack in a method with feedback control characteristics, and thus can cope with the interference caused by external environmental changes and component aging, and improve the robustness of the fuel cell system. Moreover, by using various heat transfer models and flow models to calculate the target values for adjusting the pump speed, the opening of the three-way valve, and the fan speed, a large number of calibration tests are omitted, and the calculation process of the target values is simplified. Furthermore, since there is a coupling relationship between the respective target temperatures, the operating points of the water pump, the three-way valve, and the fan are adjusted simultaneously within each control step. Therefore, when the measured value of one of the temperatures reaches the target value, the remaining temperatures will reach the target value synchronously. At the same time, the feedback control characteristics of the control method can ensure that the cooling system can reach a stable operating state when the coolant temperature at each operating point in the system reaches the target value. Description of the Drawings

[0009] In the drawings, which are not necessarily to scale, the same reference numerals may describe similar components in different views. The same reference numerals with alphabetic suffixes or different alphabetic suffixes may represent different instances of similar components. The drawings generally illustrate various embodiments by way of example and not limitation, and are used together with the description and the claims to explain the disclosed embodiments. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be an exhaustive or exclusive embodiment of the device or method.

[0010] Figure 1 A flowchart showing the temperature control method of the fuel cell system according to an embodiment of the present application;

[0011] Figure 2 A schematic structural diagram showing the fuel cell system according to an embodiment of the present application; and

[0012] Figure 3 A curve graph showing the temperature change within the fuel cell system according to an embodiment of the present application. Detailed Embodiments

[0013] To enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure will be described in detail below in conjunction with the drawings and specific embodiments. The embodiments of the present disclosure will be further described in detail below in conjunction with the drawings and specific examples, but this is not a limitation to the present disclosure.

[0014] For each of the steps described herein, if there is no necessity for a sequential relationship among them, the order in which they are described as examples herein should not be regarded as a limitation. Those skilled in the art should know that the order can be adjusted as long as the logic among them is not destroyed and the entire process cannot be implemented.

[0015] The terms "first", "second" and similar terms used in this application do not denote any order, quantity or importance, but are only used to distinguish different parts. The expressions "first" and "second" are only numbered for convenience of expression and do not aim to imply that the "first component" and the "second component" must have different physical properties. In fact, the "first component" and the "second component" can have the same or different structures, which are not limited herein, as long as the "first component" and the "second component" are discrete components. Further, when sufficient explanation is given in the context, the "first component" and the "second component" may not even be discrete components, may be integrated into the same component, or may be replaceable with each other.

[0016] In this application, when it is described that a specific device is located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When it is described that a specific device is connected to other devices, the specific device may be directly connected to the other devices without an intermediate device, or may not be directly connected to the other devices and have an intermediate device.

[0017] Words such as "comprising" or "including" mean that the elements before this word are covered by the elements listed after this word, and do not exclude the possibility of also covering other elements. "Up", "down", "left", "right", etc. are only used to represent relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0018] In some embodiments of this application, a method for controlling the temperature of a fuel cell system is provided. The fuel cell system includes a stack, a three-way valve, a radiator, a fan and a pump. The fuel cell system here can be Figure 1 the fuel cell system with the structure shown in Figure 1 or a fuel cell system with other structures. In the embodiments of this application, the fuel cell system 1 is taken as an example of the fuel cell system for illustration. As Figure 1 shown, the fuel cell system 1 includes a stack 11, a three-way valve 12, a radiator 13, a fan 14, a pump 15 and a processor 16. The coolant from the outlet of the pump 15 is fed to the stack 11. After flowing through the stack 11, the coolant is fed to the inlet of the three-way valve 12. The first outlet of the three-way valve 12 is communicated with the inlet of the radiator 13, and the second outlet is communicated with the outlet of the radiator 13 and the inlet of the pump 15. The fan 14 is used to cool the coolant flowing through the radiator 13.

[0019] Figure 2 This is a flowchart of the temperature control method for a fuel cell system according to an embodiment of the present application. As Figure 2 shown, the temperature control method includes using a processor to perform the following processing of steps S1 to S10. The processor here can be Figure 1 the processor with the structure shown in

[0020] or a processor with other structures. In the embodiment of the present application, the processor 16 is taken as an example of the processor for illustration.

[0021] In step S1, according to the target value of the temperature at the coolant outlet of the stack 11 and its first associated parameter, a correction value of the temperature at the coolant outlet of the stack 11 is determined.

[0022] Exemplarily, the correction value of the temperature at the coolant outlet of the stack 11 is calculated using the following formula (1):

[0023]

[0024] where, T corr,StackOutput is the correction value of the temperature at the coolant outlet of the stack 11, f StackOutput is a function for calculating the correction value of the temperature at the coolant outlet of the stack 11, T target,StackOutput is the target value of the temperature at the coolant outlet of the stack 11, T measure,StackOutput is the measured value of the temperature at the coolant outlet of the stack 11, is the partial derivative of the correction value of the temperature at the coolant outlet of the stack 11 with respect to its target value, is the partial derivative of the corrected value of the temperature at the coolant outlet of the stack 11 with respect to its measured value. That is, the corrected value of the temperature at the coolant outlet of the stack 11 is adjusted based on the target value of the temperature at the coolant outlet of the stack 11. Instead of directly using the latter as the corrected value, the corrected value of the temperature at the coolant outlet of the stack 11 is made non-positively correlated with the corresponding measured value, and the corrected value of the temperature at the coolant outlet of the stack 11 is made non-negatively correlated with the corresponding target value. Moreover, the first correlation parameter consists of various temperature parameters in the fuel cell system 1 determined based on actual use, so that when calculating the corrected value of the temperature at the coolant outlet of the stack 11, the feed-in and effect of the coolant temperature at each component in the fuel cell system 1 can be jointly considered, so that there is a coupling relationship between the target temperatures of each component. Using the various corrected values configured in this way instead of directly using the target value for adjustment, the adjustment can better cope with the interference caused by external environmental changes and component aging, and improve the robustness of the fuel cell system.

[0025] In step S2, according to the corrected value of the temperature at the coolant outlet of the stack 11, the target value of the total coolant flow rate is determined using the stack heat transfer model.

[0026] Specifically, the target value of the total coolant flow rate can be determined using the experimental measurement data table or can be obtained by calculating using the stack heat transfer model. The stack heat transfer model is determined based on energy conservation, the solid heat conduction formula, the solid-liquid heat transfer formula, etc. Exemplarily, the target value of the total coolant flow rate can be determined using the stack heat transfer model shown in Equation (2-1) or Equation (2-2):

[0027] U stack I stack η

[0028] = c coolany Q yotal,CoolinggSystem (T corr,StackOutput - T measure,StackInput )

[0029] …… Equation (2-1)

[0030] Or,

[0031]

[0032] Among them, U stack is the output voltage of the stack 11, I stack is the output current of the stack 11, η is the efficiency, c coolant is the specific heat capacity of the coolant, Q total,CoolingSystem is the target value of the total coolant flow rate, T corr,StackOutput is the corrected value of the temperature at the coolant outlet of the stack 11, T measure,StackInputis the measured value of the temperature at the coolant inlet of the fuel cell stack 11, κ is the thermal conductivity, A stack is the heat conduction area of the fuel cell stack 11 to air, ΔT air is the air temperature rise near the fuel cell stack 11, δ air is the thickness of the air temperature rise layer.

[0033] In step S3, according to the determined target value of the total coolant flow rate, the target value of the rotational speed of the pump 15 is determined using the pump 15 model.

[0034] Specifically, the target value of the rotational speed of the pump 15 can be determined using the experimental measurement data table or obtained by calculation using the pump model. The pump model represents the flow characteristics of the entire cooling system measured in the experiment. Exemplarily, the target value of the rotational speed of the pump 15 can be determined using the pump model shown in Equation (3-1) or Equation (3-2):

[0035] Q total,CoolingSystem = f(θ measure,ThreeWayValve , n WaterPump ,…)

[0036] …… Equation (3-1)

[0037] Or,

[0038]

[0039] where, Q total,CoolingSystem is the target value of the total coolant flow rate, θ measure,ThreeWayValve is the measured value of the opening of the three-way valve 12, n WaterPump is the target value of the rotational speed of the pump 15, and a, b, and c are all fitting coefficients based on the experimental measurement data.

[0040] In step S4, according to the target value of the temperature at the coolant inlet of the fuel cell stack 11 and its second associated parameter, the correction value of the temperature at the coolant inlet of the fuel cell stack 11 is determined.

[0041] Exemplarily, the correction value of the temperature at the coolant inlet of the fuel cell stack 11 is calculated using the following Equation (4):

[0042]

[0043] where, T corr,StackInput is the correction value of the temperature at the coolant inlet of the fuel cell stack 11, f StackInput is the function for calculating the correction value of the temperature at the coolant inlet of the fuel cell stack 11, T target,StackInput is the target value of the temperature at the coolant inlet of the fuel cell stack 11, T measure,StackInput is the measured value of the temperature at the coolant inlet of the fuel cell stack 11, is the partial derivative of the correction value of the temperature at the coolant inlet of the fuel cell stack 11 with respect to its target value. is the partial derivative of the correction value of the temperature at the coolant inlet of the fuel cell stack 11 with respect to its measured value. That is to say, the correction value of the temperature at the coolant inlet of the fuel cell stack 11 is adjusted based on the target value of the temperature at the coolant inlet of the fuel cell stack 11. Instead of directly using the latter as the correction value, the correction value of the temperature at the coolant inlet of the fuel cell stack 11 is made non-positively correlated with the corresponding measured value, and the correction value of the temperature at the coolant inlet of the fuel cell stack 11 is non-negatively correlated with the corresponding target value. Moreover, the second correlation parameter consists of various temperature parameters in the fuel cell system 1 determined based on actual use, so that when calculating the correction value of the temperature at the coolant inlet of the fuel cell stack 11, the feed-in and effect of the coolant temperature at each component in the fuel cell system 1 can be jointly considered, so that there is a coupling relationship between the target temperatures of each component. Using the various correction values constituted in this way instead of directly using the target value for adjustment, the adjustment can better cope with the interference caused by external environmental changes and component aging, and improve the robustness of the fuel cell system.

[0044] In step S5, according to the target value of the total coolant flow rate and the correction value of the temperature at the coolant inlet of the fuel cell stack 11, using the three-way valve heat transfer model, the target values of the small-circulation flow rate and the large-circulation flow rate of the coolant are determined.

[0045] Specifically, the target values of the small-circulation flow rate and the large-circulation flow rate of the coolant can be determined by using the experimental measurement data table, or can be obtained through the three-way valve heat transfer model determined based on fluid heat transfer formulas, etc.

[0046] Exemplarily, the target values of the small-circulation flow rate and the large-circulation flow rate of the coolant can be determined by using the three-way valve heat transfer model shown in Equation (5):

[0047]

[0048] where, Q m,CoolingSyste is the target value of the large-circulation flow rate of the cooling system, T measure,RadOutput is the measured value of the coolant temperature at the outlet of the radiator 13, Q s,CoolingSystem is the target value of the small-circulation flow rate of the cooling system, T measure,StackOutpu is the measured value of the coolant temperature at the outlet of the fuel cell stack 11, Q total,CoolingSyst is the target value of the total coolant flow rate, T corr,stackIntput is the correction value of the temperature at the coolant inlet of the fuel cell stack 11.

[0049] In step S6, according to the target values of the small-circulation flow rate and the large-circulation flow rate of the coolant, using the three-way valve flow model, the target value of the opening degree of the three-way valve 12 is determined.

[0050] Specifically, the target value of the opening degree of the three-way valve 12 can be determined using an experimental measurement data table or obtained by calculating through a three-way valve flow model. The three-way valve flow model represents the characteristics of the large and small circulation flow split ratios of the entire cooling system measured experimentally, which are affected by the opening degree of the three-way valve.

[0051] Q m,CoolingSys = αQ total,CoolingSystem ……Equation (6-1)

[0052] Where α is the flow split ratio, Q m,CoolingSystem is the target value of the large circulation flow of the cooling system, and θ target,ThreeWayValve is the target value of the opening degree of the three-way valve 12.

[0053] The relationship between the flow split ratio α and the target value θ target,ThreeWayValve of the opening degree of the three-way valve 12 can be expressed as a table of experimental measurement data or a polynomial fitting formula, but is not limited thereto. For example, a fitting formula as shown in Equation (6-2) can be used to represent it:

[0054] θ target,ThreeWayValve = a * α 2 + b * α + c……Equation (6-2)

[0055] Where a, b, and c are all fitting coefficients based on experimental measurement data.

[0056] In step S7, according to the target value of the coolant temperature at the outlet of the radiator 13 and its third associated parameter, the correction value of the coolant temperature at the outlet of the radiator 13 is determined.

[0057] Exemplarily, the following Equation (7) is used to calculate the correction value of the coolant temperature at the outlet of the radiator 13:

[0058]

[0059] Where T corr,RadOutput is the correction value of the coolant temperature at the outlet of the radiator 13, f RadOutput is the function used to calculate the correction value of the coolant temperature at the outlet of the radiator 13, T target,RadOutput is the target value of the coolant temperature at the outlet of the radiator 13, T measure,RadOutput is the measured value of the coolant temperature at the outlet of the radiator 13, is the partial derivative of the correction value of the coolant temperature at the outlet of the radiator 13 with respect to its target value, The partial derivative of the correction value of the coolant temperature at the outlet of the radiator 13 with respect to its measured value. That is, the correction value of the coolant temperature at the outlet of the radiator 13 is adjusted based on the target value of the coolant temperature at the outlet of the radiator 13. Instead of directly using the latter as the correction value, the correction value of the coolant temperature at the outlet of the radiator 13 is made non-positively correlated with the corresponding measured value, and the correction value of the coolant temperature at the outlet of the radiator 13 is made non-negatively correlated with the corresponding target value. Moreover, the third correlation parameter consists of various temperature parameters in the fuel cell system 1 determined based on actual use, so that when calculating the correction value of the coolant temperature at the outlet of the radiator 13, the feed-in and effect of the coolant temperature at each component in the fuel cell system 1 can be jointly considered, so that there is a coupling relationship between the target temperatures of each component. Using the various correction values thus constituted instead of directly using the target value for adjustment, the adjustment can better cope with the interference caused by external environmental changes and component aging, and improve the robustness of the fuel cell system.

[0060] In step S8, according to the correction value of the coolant temperature at the outlet of the radiator 13, the target value of the large circulation flow rate of the coolant, the measured value of the coolant temperature at the inlet of the radiator 13, and the measured value of the air temperature, the heat transfer model of the radiator is used to determine the target value of the air flow rate of the radiator 13.

[0061] Specifically, the target value of the air flow rate of the radiator 13 can be determined using an experimental measurement data table or can be obtained by calculating with the radiator heat transfer model. The radiator heat transfer model is determined based on the solid heat conduction formula, the solid-gas heat transfer formula, etc. Exemplarily, the target value of the air flow rate of the radiator 13 can be determined using the radiator heat transfer model shown in Equation (8):

[0062] c coolant W m,CoolingSysten ΔT coolant -c air Q air ΔT air =0……Equation (8)

[0063] Wherein, c coolant is the specific heat capacity of the coolant, Q m,CoolingSystem is the target value of the large circulation flow rate of the coolant, ΔT coolant is the temperature drop of the coolant flowing through the radiator 13, c air is the specific heat capacity of the air flowing through the radiator 13, Q air is the target value of the air flow rate of the radiator 13, ΔT air is the temperature rise of the air flowing through the radiator 13. Moreover, ΔT coolant can be the measured value T of the temperature at the coolant outlet of the stack 11 measure,StackOutput and the correction value T of the coolant temperature at the outlet of the radiator 13corr,RadOutpu The difference can also be the measured value T of the coolant temperature at the inlet of the radiator 13 measure,RadInput and the corrected value T of the coolant temperature at the outlet of the radiator 13 corr,RadOutpu The difference is ΔT air It can be the measured value T of the coolant temperature at the outlet of the radiator 13 measure,RadOutput and the temperature T of the air near the radiator air The difference. The difference can also be the measured value T of the coolant temperature at the inlet of the radiator 13 measure,RadInput and the temperature T of the air near the radiator air The difference

[0064] In step S9, according to the target value of the air flow rate of the radiator 13, using the fan flow model, calculate the target value of the rotational speed of the fan 14

[0065] Specifically, the target value of the rotational speed of the fan 14 can be determined by using the experimental measurement data table or obtained by calculation through the fan flow model. The fan flow model represents the characteristics of the experimentally measured fan flow rate affected by the rotational speed. The relationship between the fan flow rate and the rotational speed can be expressed as a table of experimental measurement data or a polynomial fitting formula, but it is not limited thereto. For example, the fitting formula shown in Equation (9-1) or Equation (9-2) can be used to represent it

[0066]

[0067] Or

[0068] n fan = a * Q air + b... Equation (9-2)

[0069] Wherein, n fan is the target value of the rotational speed of the fan 14, Q air is the target value of the air flow rate of the radiator 13, and a, b, and c are all fitting coefficients based on experimental measurement data

[0070] In step S10, according to the target value of the rotational speed of the pump 15, the target value of the opening degree of the three-way valve 12, and the target value of the rotational speed of the fan 14, adjust the rotational speed of the pump 15, the opening degree of the three-way valve 12, and the rotational speed of the fan 14

[0071] Through the temperature control method of the fuel cell system of the present application, the target value and the measured value of the temperature such as the temperature at the coolant outlet of the stack are used to calculate the correction value, and the correction value of the temperature such as the temperature at the coolant outlet of the stack is calculated by a method with feedback control characteristics, so as to be able to cope with the interference caused by external environmental changes and component aging, and improve the robustness of the fuel cell system. Moreover, by using various heat transfer models and flow models to calculate the target values for adjusting the rotational speed of the pump, the opening degree of the three-way valve, and the rotational speed of the fan, a large number of calibration tests are omitted, and the calculation process of the target values is simplified. Furthermore, since there is a coupling relationship between the respective target temperatures, the operating points of the water pump, the three-way valve, and the fan are adjusted simultaneously within each control step. Therefore, when the measured value of one of the temperatures reaches the target value, the remaining temperatures will reach the target value synchronously. At the same time, the feedback control characteristics of the control method can ensure that the cooling system reaches a stable operating state when the coolant temperature at each operating point within the system reaches the target value.

[0072] In some embodiments, the processor 16 includes an electronic control unit, and the processing is performed by the electronic control unit within each control step.

[0073] Specifically, within each control step, the electronic control unit executes the calculations of steps S1 to S10 once to adjust the rotational speed of the pump 15, the opening degree of the three-way valve 12, and the rotational speed of the fan 14 in the fuel cell system 1, so as to keep the operating temperature of the fuel cell system 1 stable.

[0074] In some embodiments, the correction value of the temperature at the coolant outlet of the stack 11 is different from the target value of the temperature at the coolant outlet of the stack 11, but on the basis of the target value of the temperature at the coolant outlet of the stack 11, a first adjustment amount is introduced. The first adjustment amount characterizes the influence of the target value and / or the measured value of the temperature at other positions of the stack 11 and / or the fluid outlet and / or inlet of the device that is fluidly connected to the stack 11.

[0075] Exemplarily, the first adjustment amount can characterize the influence of the measured value of the temperature at the coolant outlet of the stack 11 on the target value of the temperature at the coolant outlet of the stack 11, or can characterize the influence of the target value and / or the measured value of the temperature at the coolant inlet of the stack 11 on the target value of the temperature at the coolant outlet of the stack 11, or can also characterize the influence of the target value and / or the measured value of the coolant temperature at the outlet and / or inlet of the radiator 13 on the target value of the temperature at the coolant outlet of the stack 11. The specific parameters in the first adjustment amount are determined based on the experimental measurement parameters determined for actual use.

[0076] When the first adjustment amount characterizes the influence of the measured value of the temperature at the coolant outlet of the stack 11 on the target value of the temperature at the coolant outlet of the stack 11, the following formula (10) can be used to calculate the first adjustment amount:

[0077] T cont,StackOutput

[0078] = 2T target,StackOutput - T measure,StackOutput + ∫(T target,StackOutput - T measure,stackOutput )

[0079] …… Formula (10)

[0080] Where, T cont,StackOutput is the first adjustment amount, T target,StackOutput is the target value of the temperature at the coolant outlet of the stack 11, and T measure,StackOutput is the measured value of the temperature at the coolant outlet of the stack 11.

[0081] In this way, when calculating the correction value of the temperature at the coolant outlet of the stack 11, the coolant temperatures at various components in the fuel cell system 1 can be jointly considered, so that there is a coupling relationship between the target temperatures of various components. Therefore, the operating points of the water pump, the three-way valve, and the fan will be adjusted simultaneously in each control step.

[0082] Figure 3 shows the change process of each temperature in the fuel cell system 1 within a control step. As Figure 3 shown, the temperature at the coolant outlet of the stack 11 and the temperature at the coolant inlet of the stack 11 rise from the initial value under control and are maintained after reaching the target value; at the same time, the coolant temperature at the outlet of the radiator 13 is maintained after reaching the target value. Through Figure 3 the various temperature curves, it can be intuitively understood that when the measured values of the temperature at the coolant outlet of the stack 11 and the temperature at the coolant inlet of the stack 11 tend to and reach the target value, the other temperatures, such as the measured value of the coolant temperature at the outlet of the radiator 13, will tend to and reach the target value synchronously. Generally speaking, each temperature reaches the target value almost synchronously, so that the operating temperatures at various parts of the fuel cell system 1 are the same to ensure that the fuel cell system 1 operates at a stable operating temperature.

[0083] In some embodiments, the first correlation parameter includes a measured value of the temperature at the coolant outlet of the stack 11, and a corrected value of the temperature at the coolant outlet of the stack 11 is determined based on a first difference between a target value and the measured value of the temperature at the coolant outlet of the stack 11. The first difference may be the temperature difference between the target value and the measured value of the temperature at the coolant outlet of the stack 11, but is not limited thereto. It may also be other differences that can be used to determine the corrected value of the temperature at the coolant outlet of the stack 11.

[0084] In some embodiments, the first correlation parameter further includes the target value and the measured value of the temperature at the coolant inlet of the stack 11.

[0085] Specifically, when calculating the corrected value of the temperature at the coolant outlet of the stack 11, as long as it is ensured that the corrected value T of the temperature at the coolant outlet of the stack 11 corr,StackOutput is non-negatively correlated with the target value T of the temperature at the coolant outlet of the stack 11 target,StackOutput and is non-positively correlated with the measured value T of the temperature at the coolant outlet of the stack 11 measure,StackOutput any first correlation parameter composed of experimentally measured parameters determined based on actual use can be used to determine the corrected value of the temperature at the coolant outlet of the stack 11.

[0086] In some embodiments, the corrected value of the temperature at the coolant outlet of the stack 11 is determined based on a proportional term and an integral term of the first difference.

[0087] Exemplarily, the corrected value of the temperature at the coolant outlet of the stack 11 can be determined by a proportional-integral (PI) calculation method based on the temperature difference between the target value and the measured value of the temperature at the coolant outlet of the stack 11. The integral term and the proportional term values of the temperature difference between the target value and the measured value of the temperature at the coolant outlet of the stack 11 in the current control step are calculated respectively, and the corrected value of the temperature at the coolant outlet of the stack 11 is obtained using proportional-integral calculation.

[0088] In some embodiments, the corrected value of the temperature at the coolant inlet of the stack 11 is different from the target value of the temperature at the coolant inlet of the stack 11, but on the basis of the target value of the temperature at the coolant inlet of the stack 11, a second adjustment amount is introduced. The second adjustment amount characterizes the influence of the target value and / or the measured value of the temperature at other positions of the stack 11 and / or at the fluid outlet and / or inlet of a device that is in fluid communication with the stack 11.

[0089] Exemplarily, the second adjustment amount may characterize the influence of the target value and / or measured value of the temperature at the coolant outlet of the stack 11 on the target value of the temperature at the coolant inlet of the stack 11, may also characterize the influence of the measured value of the temperature at the coolant inlet of the stack 11 on the target value of the temperature at the coolant inlet of the stack 11, and may further characterize the influence of the target value and / or measured value of the coolant temperature at the outlet and / or inlet of the radiator 13 on the target value of the temperature at the coolant inlet of the stack 11. The specific parameters in the second adjustment amount are determined based on the experimental measurement parameters determined in actual use.

[0090] In this way, when calculating the corrected value of the temperature at the coolant inlet of the stack 11, the coolant temperatures at various components in the fuel cell system 1 can be jointly considered, such that there is a coupling relationship between the target temperatures of the various components. Therefore, within each control step, the operating points of the water pump, the three-way valve, and the fan are adjusted simultaneously.

[0091] In some embodiments, the second correlation parameter includes the measured value of the temperature at the coolant inlet of the stack 11, and the corrected value of the temperature at the coolant inlet of the stack 11 is determined based on the second difference between the target value and the measured value of the temperature at the coolant inlet of the stack 11. The second difference may be the temperature difference between the target value and the measured value of the temperature at the coolant inlet of the stack 11, but is not limited thereto. It may also be other differences that can be used to determine the corrected value of the temperature at the coolant inlet of the stack 11.

[0092] In some embodiments, the second correlation parameter further includes the target value and the measured value of the coolant temperature at the outlet of the radiator 13.

[0093] Specifically, when calculating the corrected value of the temperature at the coolant inlet of the stack 11, as long as it is ensured that the corrected value T of the temperature at the coolant inlet of the stack 11 corr,StackInput is non-negatively correlated with the target value T of the temperature at the coolant inlet of the stack 11 target,StackInput and is non-positively correlated with the measured value T of the temperature at the coolant inlet of the stack 11 measure,StackInput any second correlation parameter composed of experimental measurement parameters determined in actual use can be used to determine the corrected value of the temperature at the coolant inlet of the stack 11.

[0094] In some embodiments, the corrected value of the temperature at the coolant inlet of the stack 11 is determined based on the proportional term and the integral term of the second difference.

[0095] Exemplarily, the values of the integral term and the proportional term of the temperature difference between the target value and the measured value of the temperature at the coolant inlet of the stack 11 in the current control step can be calculated respectively, and the corrected value of the temperature at the coolant inlet of the stack 11 is obtained using proportional-integral calculation.

[0096] In some embodiments, the corrected value of the coolant temperature at the outlet of the radiator 13 is different from the target value of the coolant temperature at the outlet of the radiator 13. Instead, on the basis of the target value of the coolant temperature at the outlet of the radiator 13, a third adjustment amount is introduced. The third adjustment amount characterizes the influence of the target value and / or measured value of the temperature at other positions of the radiator 13 and / or the fluid outlet and / or inlet of the device that is in fluid communication with the radiator 13.

[0097] Exemplarily, the third adjustment amount can characterize the influence of the target value and / or measured value of the temperature at the coolant outlet and / or inlet of the stack 11 on the target value of the coolant temperature at the outlet of the radiator 13, can also characterize the influence of the target value and / or measured value of the coolant temperature at the inlet of the radiator 13 on the target value of the coolant temperature at the outlet of the radiator 13, and can further characterize the influence of the measured value of the coolant temperature at the outlet of the radiator 13 on the target value of the coolant temperature at the outlet of the radiator 13. The specific parameters in the third adjustment amount are determined based on the experimental measurement parameters determined by actual use.

[0098] In this way, when calculating the corrected value of the coolant temperature at the outlet of the radiator 13, the coolant temperatures at various components in the fuel cell system 1 can be jointly considered, so that there is a coupling relationship between the target temperatures of the various components. Therefore, the operating points of the water pump, the three-way valve, and the fan are adjusted simultaneously in each control step.

[0099] In some embodiments, the third correlation parameter includes the measured value of the coolant temperature at the outlet of the radiator 13, and the corrected value of the coolant temperature at the outlet of the radiator 13 is determined based on the third difference between the target value and the measured value of the coolant temperature at the outlet of the radiator 13. The third difference can be the temperature difference between the target value and the measured value of the coolant temperature at the outlet of the radiator 13, but is not limited thereto. It can also be other differences that can be used to determine the corrected value of the coolant temperature at the outlet of the radiator 13.

[0100] In some embodiments, the third correlation parameter further includes the target value and the measured value of the temperature at the coolant inlet of the stack 11, and the target value and the measured value of the temperature at the coolant outlet of the stack 11.

[0101] Specifically, when calculating the corrected value of the coolant temperature at the outlet of the radiator 13, as long as it is ensured that the corrected value T of the coolant temperature at the outlet of the radiator 13 corr,RadOutput is non-negatively correlated with the target value T of the coolant temperature at the outlet of the radiator 13 target,RadOutput and is non-positively correlated with the measured value T of the coolant temperature at the outlet of the radiator 13 measure,RadOutput any third correlation parameter composed of experimental measurement parameters determined by actual use can be used to determine the corrected value of the coolant temperature at the outlet of the radiator 13.

[0102] In some embodiments, the correction value of the coolant temperature at the outlet of the radiator 13 is determined based on the proportional term and the integral term of the third difference.

[0103] Exemplarily, the values of the integral term and the proportional term of the temperature difference between the target value and the measured value of the coolant temperature at the outlet of the radiator 13 in the current control step can be calculated respectively, and the correction value of the coolant temperature at the outlet of the radiator 13 can be obtained by using proportional-integral calculation.

[0104] In some embodiments of the present application, a fuel cell system is provided. As Figure 1 shown, the fuel cell system 1 includes a stack 11, a three-way valve 12, a radiator 13, a fan 14, a pump 15, and a processor 16. The coolant from the outlet of the pump 15 is fed to the stack 11. After flowing through the stack 11, the coolant is fed to the inlet of the three-way valve 12. The first outlet of the three-way valve 12 is communicated with the inlet of the radiator 13, and the second outlet is communicated with the outlet of the radiator 13 and the inlet of the pump 15. The fan 14 is used to cool the coolant flowing through the radiator 13. The processor 16 is configured to execute the temperature control method of the fuel cell system according to various embodiments of the present application.

[0105] The heat dissipation part 20 in the fuel cell system 1 is configured to include a radiator 13 and a fan 14. The processor 16 can execute the cooling control method of the fuel cell system 1 according to various embodiments of the present application. Each step, processing details or examples of the cooling control methods of various embodiments of the present application can be selectively combined herein and will not be elaborated herein.

[0106] The temperature control method and the fuel cell system of the present application calculate the correction value by using the target value and the measured value of the temperature such as the temperature at the coolant outlet of the stack, and calculate the correction value of the temperature such as the temperature at the coolant outlet of the stack by a method with feedback control characteristics, so as to be able to cope with the interference caused by external environmental changes and component aging, and improve the robustness of the fuel cell system. Moreover, by using various heat transfer models and flow models to calculate the target values for adjusting the rotational speed of the pump, the opening degree of the three-way valve, and the rotational speed of the fan, a large number of calibration tests are omitted, and the calculation process of the target values is simplified. Furthermore, since there is a coupling relationship between the target temperatures, the operating points of the water pump, the three-way valve, and the fan will be adjusted simultaneously in each control step. Therefore, when the measured value of one of the temperatures approaches or reaches the target value, the remaining temperatures will approach or reach the target value synchronously. At the same time, the feedback control characteristics of the control method can ensure that the cooling system can reach a stable operating state when the coolant temperature at each operating point in the system reaches the target value.

[0107] In addition, although exemplary embodiments have been described herein, the scope includes any and all embodiments based on the present disclosure with equivalent elements, modifications, omissions, combinations (e.g., various embodiments intersecting schemes), adaptations or changes. The elements in the claims will be interpreted broadly based on the language adopted in the claims, and are not limited to the examples described in this specification or during the implementation of this application, and the examples will be interpreted as non-exclusive. Therefore, this specification and examples are intended to be considered as examples only, and the true scope and spirit are indicated by the following claims and the full scope of their equivalents.

[0108] The above description is intended to be illustrative rather than restrictive. For example, the above examples (or one or more of them) can be used in combination with each other. For example, a person of ordinary skill in the art can use other embodiments when reading the above description. In addition, in the above-mentioned specific embodiments, various features can be grouped together to simplify the present disclosure. This should not be interpreted as an intention that a disclosed feature that is not required to be protected is necessary for any claim. On the contrary, the subject matter of the present invention may be less than all the features of a specific disclosed embodiment. Thus, the following claims are incorporated into the specific embodiments as examples or embodiments, wherein each claim is independently used as a separate embodiment, and it is considered that these embodiments can be combined with each other in various combinations or arrangements. The scope of the present invention should be determined with reference to the attached claims and the full scope of equivalent forms granted by these claims.

Claims

1. A temperature control method for a fuel cell system, the fuel cell system comprising a stack, a three-way valve, a radiator, a fan and a pump, coolant from the outlet of the pump being fed to the stack, the coolant flowing through the stack and then being fed to the inlet of the three-way valve, a first outlet of the three-way valve being in communication with the inlet of the radiator and a second outlet being in communication with the outlet of the radiator and the inlet of the pump, the fan being used to cool the coolant flowing through the radiator, characterized in that, The temperature control method includes the following processing performed by a processor: Determine a correction value for the temperature at the coolant outlet of the stack based on a target value of the temperature at the coolant outlet of the stack and its first associated parameter; Determine a target value for the total coolant flow rate using a stack heat transfer model based on the correction value for the temperature at the coolant outlet of the stack; Determine a target value for the rotational speed of the pump using a pump model based on the determined target value for the total coolant flow rate; Determine a correction value for the temperature at the coolant inlet of the stack based on a target value of the temperature at the coolant inlet of the stack and its second associated parameter; Determine target values for the small-circulation flow rate and the large-circulation flow rate of the coolant using a three-way valve heat transfer model based on the target value for the total coolant flow rate and the correction value for the temperature at the coolant inlet of the stack; Determine a target value for the opening of the three-way valve using a three-way valve flow rate model based on the target values for the small-circulation flow rate and the large-circulation flow rate of the coolant; Determine a correction value for the temperature of the coolant at the radiator outlet based on a target value of the temperature of the coolant at the radiator outlet and its third associated parameter; Determine a target value for the air flow rate of the radiator using a radiator heat transfer model based on the correction value for the temperature of the coolant at the radiator outlet, the target value for the large-circulation flow rate of the coolant, the measured value of the temperature of the coolant at the radiator inlet, and the measured value of the air temperature; Calculate a target value for the rotational speed of the fan using a fan flow rate model based on the target value for the air flow rate of the radiator; And Adjust the rotational speed of the pump, the opening of the three-way valve, and the rotational speed of the fan based on the target value for the rotational speed of the pump, the target value for the opening of the three-way valve, and the target value for the rotational speed of the fan.

2. The temperature control method according to claim 1, characterized in that The processor includes an electronic control unit, and the processing is performed by the electronic control unit within each control step.

3. The temperature control method according to claim 1, characterized in that The correction value for the temperature at the coolant outlet of the stack is different from the target value of the temperature at the coolant outlet of the stack. Instead, on the basis of the target value of the temperature at the coolant outlet of the stack, a first adjustment amount is introduced, and the first adjustment amount characterizes the influence of the target value and / or the measured value of the temperature at other positions of the stack and / or the fluid outlet and / or inlet of the device that is in fluid communication with the stack.

4. The temperature control method according to claim 1, wherein The first associated parameter includes the measured value of the temperature at the coolant outlet of the stack, and the correction value for the temperature at the coolant outlet of the stack is determined based on a first difference between the target value and the measured value of the temperature at the coolant outlet of the stack.

5. The temperature control method according to claim 4, wherein The first associated parameter further includes the target value and the measured value of the temperature at the coolant inlet of the stack.

6. The temperature control method according to claim 4 or 5, characterized in that, The correction value for the temperature at the coolant outlet of the stack is determined based on a proportional term and an integral term of the first difference.

7. The temperature control method according to claim 1, wherein The correction value for the temperature at the coolant inlet of the stack is different from the target value of the temperature at the coolant inlet of the stack. Instead, on the basis of the target value of the temperature at the coolant inlet of the stack, a second adjustment amount is introduced, and the second adjustment amount characterizes the influence of the target value and / or the measured value of the temperature at other positions of the stack and / or the fluid outlet and / or inlet of the device that is in fluid communication with the stack.

8. The temperature control method according to claim 1, wherein The second associated parameter includes a measured value of the temperature at the coolant inlet of the stack, and a corrected value of the temperature at the coolant inlet of the stack is determined based on a second difference between a target value and the measured value of the temperature at the coolant inlet of the stack.

9. The temperature control method according to claim 8, wherein The second associated parameter further includes a target value and a measured value of the coolant temperature at the radiator outlet.

10. The temperature control method according to claim 8 or 9, characterized in that, The corrected value of the temperature at the coolant inlet of the stack is determined based on a proportional term and an integral term of the second difference.

11. The temperature control method according to claim 1, wherein The corrected value of the coolant temperature at the radiator outlet is different from the target value of the coolant temperature at the radiator outlet. Instead, on the basis of the target value of the coolant temperature at the radiator outlet, a third adjustment amount is introduced, and the third adjustment amount characterizes the influence of the target value and / or the measured value of the temperature at other positions of the radiator and / or at the fluid outlet and / or inlet of a device that is in fluid communication with the radiator.

12. The temperature control method according to claim 11, characterized in that, The third associated parameter includes a measured value of the coolant temperature at the radiator outlet, and a corrected value of the coolant temperature at the radiator outlet is determined based on a third difference between the target value and the measured value of the coolant temperature at the radiator outlet.

13. The temperature control method according to claim 12, wherein The third associated parameter further includes the target value and the measured value of the temperature at the coolant inlet of the stack, and the target value and the measured value of the temperature at the coolant outlet of the stack.

14. The temperature control method according to claim 12 or 13, characterized in that, The corrected value of the coolant temperature at the radiator outlet is determined based on a proportional term and an integral term of the third difference.

15. A fuel cell system, characterized in that, Comprising a stack, a three-way valve, a radiator, a fan, a pump, and a processor, coolant from the outlet of the pump is fed to the stack, the coolant flows through the stack and then is fed to the inlet of the three-way valve, a first outlet of the three-way valve is in communication with the inlet of the radiator while a second outlet is in communication with the outlet of the radiator and the inlet of the pump, the fan is used to cool the coolant flowing through the radiator, and the processor is configured to execute the temperature control method of the fuel cell system according to any one of claims 1-14.

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