Cooling control method of fuel cell system and fuel cell system

Abstract

The invention provides a cooling control method of a fuel cell system and the fuel cell system. Determining a first opening degree of the three-way valve at each moment based on the target value of the cooling liquid temperature at the inlet of the electric pile, the measured value of the cooling liquid temperature at the outlet of the electric pile and the measured value of the cooling liquid temperature at the outlet of the radiator; when the current operation state of the system meets the allowable condition of feedback regulation of the three-way valve, determining a second opening degree of the three-way valve at each moment based on a proportional term of a difference value between a target value and a measured value of the temperature of the cooling liquid at the inlet of the galvanic pile and an integral term relative to the moment; processing for maintaining or suppressing an integral accumulation value of the difference value at the previous time relative to the integral term at the time according to the sum of the first opening degree and the second opening degree of the three-way valve at the current time; and determining a second opening degree of the three-way valve after processing at the current moment and determining a target opening degree of the three-way valve at the current moment so as to realize rapid adjustment of the temperature of the cooling liquid at the inlet of the electric pile.

Description

Technical Field

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

[0002] When the fuel cell stack is operating, there are strict requirements for the coolant temperature at the inlet of the stack and the coolant temperature at the outlet of the stack. Maintaining a good operating temperature is beneficial to the performance and lifespan of the fuel cell stack. In a fuel cell system, adjusting a three-way valve can achieve the purpose of precisely controlling the coolant temperature at the inlet of the stack.

[0003] The three-way valve can adjust the proportion of the coolant flow in the large circulation and the small circulation, so as to achieve the purpose of precisely controlling the coolant temperature at the inlet of the stack. Generally, a feedforward plus feedback control method is used.

[0004] However, when using a basic proportional-integral (PI) controller for feedback control of the coolant temperature at the inlet of the stack, the temperature control effect shows a certain delay. The feedback opening of the three-way valve cannot quickly respond to the temperature change, resulting in a delay in temperature adjustment. Summary of the Invention

[0005] In view of the above problems, this application is proposed to solve the above problems existing in the prior art.

[0006] The purpose of this application is to provide a cooling control method for a fuel cell system and a fuel cell system, which can control the feedback opening of the three-way valve to quickly respond to the temperature change, so as to achieve the purpose of stably controlling the coolant temperature at the inlet of the stack.

[0007] According to a first aspect of the present disclosure, a cooling control method for a fuel cell system is provided. The fuel cell system includes a stack, a three-way valve, a radiator, a fan, a pump, and a controller. The cooling control method includes the controller performing the following processes:

[0008] Based on the target value of the coolant temperature at the inlet of the stack, the measured value of the coolant temperature at the outlet of the stack, and the measured value of the coolant temperature at the outlet of the radiator, determine the first opening of the three-way valve at each moment;

[0009] When the current operating state of the fuel cell system meets the allowable conditions for feedback regulation of the three-way valve, based on the proportional term and the integral term with respect to time of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack, determine the second opening of the three-way valve at each moment; and,

[0010] Maintain or suppress the integral cumulative value at the previous moment of the integral term of the difference with respect to time according to the sum of the first opening degree and the second opening degree of the three-way valve at the current moment, and then determine the processed second opening degree of the three-way valve at the current moment accordingly. Based on the first opening degree and the processed second opening degree of the three-way valve at the current moment, determine the target opening degree of the three-way valve at the current moment.

[0011] According to the second solution 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 controller. 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 controller is configured to execute the cooling control method of the fuel cell system according to various embodiments of the present application.

[0012] The cooling control method of the fuel cell system of the present application sets the allowable conditions for feedback regulation and performs feedback calculation only when the allowable conditions are met, avoiding unnecessary integral operations in some operating states, thereby avoiding sudden changes in the opening degree of the three-way valve when the operating state of the fuel cell system changes. Moreover, during feedback calculation, maintain or suppress the value of the integral term in the calculation of the second opening degree, dynamically limit the range of the integral cumulative value of the integral term, so that the feedback opening degree of the three-way valve can quickly respond to temperature changes, thereby further stably controlling the temperature of the coolant at the inlet of the stack. Description of the Drawings

[0013] In the drawings which are not necessarily drawn 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 illustrate 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 exhaustive or exclusive embodiments of the device or method.

[0014] Figure 1 A schematic structural diagram of a fuel cell system according to an embodiment of the present application is shown;

[0015] Figure 2 A flowchart of the cooling control method of the fuel cell system according to Example 1 of the embodiment of the present application is shown;

[0016] Figure 3 A flowchart of determining the proportional coefficient and the integral coefficient according to an embodiment of the present application is shown;

[0017] Figure 4 Shows a relationship curve graph of a proportionality coefficient and an integral coefficient according to an embodiment of the present application; and

[0018] Figure 5 Shows a flowchart of a cooling control method for a fuel cell system according to Example 2 of an embodiment of the present application. Detailed implementation manners

[0019] 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 accompanying drawings and specific implementation manners. The embodiments of the present disclosure will be further described in detail below in conjunction with the accompanying drawings and specific examples, but it is not a limitation to the present disclosure.

[0020] For each step described herein, if there is no necessity for a sequential relationship between 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 they can be adjusted in order, as long as the logic between them is not destroyed and the entire process cannot be realized.

[0021] The "first", "second" and similar terms used in the present application do not indicate 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 are not intended 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.

[0022] In the present 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.

[0023] Words such as "including" or "comprising" mean that the elements before the word cover the elements listed after the 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.

[0024] In some embodiments of the present application, a cooling control method for a fuel cell system is provided. The fuel cell system includes a stack, a three-way valve, a radiator, a fan, a pump, and a controller. The fuel cell system here can be Figure 1 the fuel cell system with the structure shown in Figure 1 , or can be a fuel cell system with other structures. In the embodiments of the present application, the fuel cell system 1 is taken as an example of the fuel cell system for illustration. As

[0025] shown, the fuel cell system 1 includes a stack 11, a pump 12, a three-way valve 13, a fan 14, a radiator 15, a coolant temperature sensor 16 at the inlet of the stack, a coolant temperature sensor 17 at the outlet of the stack, a coolant temperature sensor 18 at the outlet of the radiator, and a controller 19.

[0026] Figure 2 is a flowchart of the cooling control method for the fuel cell system according to Example 1 of the embodiments of the present application. As Figure 2 shown, in Example 1, the cooling control method includes performing the following processing of steps S101 to S102 by using the controller 19:

[0027] In step S101, based on the target value of the coolant temperature at the inlet of the stack 11, the measured value of the coolant temperature at the outlet of the stack 11, and the measured value of the coolant temperature at the outlet of the radiator 15, the first opening degree of the three-way valve 13 at each moment is determined. Exemplarily, the first opening degree can be the feedforward opening degree of the three-way valve, but is not limited thereto. The first opening degree can be calculated by using one or more of the target value of the coolant temperature at the inlet of the stack 11, the measured value of the coolant temperature at the outlet of the stack 11, and the measured value of the coolant temperature at the outlet of the radiator 15, or can be obtained by looking up a table according to one or more of these three values. The measured value of the coolant temperature at the outlet of the stack 11 is measured by using the coolant temperature sensor 17 at the outlet of the stack, and the measured value of the coolant temperature at the outlet of the radiator 15 is measured by using the coolant temperature sensor 18 at the outlet of the radiator.

[0028] In step S102, when the current operating state of the fuel cell system 1 satisfies the allowable conditions for the feedback regulation of the three-way valve 13, the second opening degree of the three-way valve 13 at each moment is determined based on the proportional term of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack 11 and the integral term with respect to time.

[0029] Specifically, when the current operating state of the fuel cell system 1 is in the power generation process, it is determined that the current operating state satisfies the allowable conditions for the feedback regulation of the three-way valve, that is, it is determined that the opening degree of the three-way valve 13 needs to be adjusted by feedback regulation when the fuel cell system 1 is in the current operating state. When the current operating state of the fuel cell system 1 is any one of the start-up, shutdown, and rapid warm-up processes, it is determined that the current operating state does not satisfy the allowable conditions for the feedback regulation of the three-way valve, that is, it is determined that the opening degree of the three-way valve 13 does not need to be adjusted by feedback regulation when the fuel cell system 1 is in the current operating state.

[0030] The second opening degree can be the feedback opening degree of the three-way valve, but it is not limited thereto. When it is determined that the current operating state satisfies the allowable conditions for the feedback regulation of the three-way valve 13, the second opening degree of the three-way valve can be determined, for example, by a proportional-integral (PI) calculation method, based on the proportional term of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack 11 and the integral term with respect to time.

[0031] Judging the feedback regulation conditions of the three-way valve and calculating the second opening degree only when the current operating state of the fuel cell system 1 satisfies the allowable conditions for the feedback regulation of the three-way valve can avoid unnecessary integral operations, avoid sudden changes in the opening degree of the three-way valve 13, and thus contribute to the stable control of the water temperature.

[0032] For example, during the rapid warm-up process of cold start, the actual water temperature at the inlet of the stack can be heated to a relatively high temperature exceeding the target water temperature at the inlet of the stack. In this case, if the feedback regulation of the three-way valve is calculated, a relatively large value of the integral term will be accumulated. During the rapid warm-up process, the three-way valve 13 is set to be fully closed forcibly, so the feedback of the integral term does not play a role in the actual control of the opening of the three-way valve during the rapid warm-up process. However, after the fuel cell system 1 jumps to the normal operating state of the power generation process, since a relatively large value has been accumulated in the value of the integral term, directly using the value of the integral term accumulated up to the previous moment to calculate the target opening of the three-way valve 13 at the current moment will cause the three-way valve 13 to open to a relatively excessive opening, which will lead to a rapid decrease in the actual water temperature at the inlet of the stack. By judging the feedback regulation condition of the three-way valve, the integral term of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack 11 is integrated only at necessary times, avoiding the continuous accumulation of the value of the integral term in an unreasonable stage, and further causing a sudden change in the opening of the three-way valve 13 when the operating state of the fuel cell system 1 changes.

[0033] In step S103, according to the sum of the first opening and the second opening of the three-way valve 13 at the current moment, the integral cumulative value of the previous moment of the integral term of the difference is maintained or suppressed, and then the processed second opening of the three-way valve 13 at the current moment is determined accordingly. Based on the first opening and the processed second opening of the three-way valve 13 at the current moment, the target opening of the three-way valve 13 at the current moment is determined.

[0034] Exemplarily, when the feedback regulation permission condition of the three-way valve 13 is satisfied and the second opening of the three-way valve 13 is calculated, further judge the magnitude of the sum of the first opening, the proportional term value of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack 11, and the value of the integral term of the difference with respect to time, and accordingly maintain or suppress the value of the integral term accumulated up to the previous moment. Here, the value of the integral term accumulated up to the previous moment refers to the integral cumulative value of the integral term of the previous moment of the current moment.

[0035] Different from the commonly used clamping or saturation methods, the method in the embodiments of the present application judges the magnitude of the sum of the first opening, the proportional term value of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack 11, and the value of the integral term of the difference with respect to time in real time, dynamically limits the value of the integral term accumulated up to the previous moment to a relatively low value, so that the value of the integral term can be dynamically within a reasonable range, and the integral term will not generate an unnecessary excessive cumulative value. In this way, when the second opening needs to be adjusted in the reverse direction, since there is no need to eliminate an excessive integral cumulative value, the second opening can be calculated more quickly, thereby reducing the delay of water temperature control.

[0036] The cooling control method of the fuel cell system of the present application sets the allowable conditions for feedback regulation and performs feedback calculation only when the allowable conditions are met, avoiding unnecessary integral operations in some operating states, thereby preventing sudden changes in the opening degree of the three-way valve when the operating state of the fuel cell system changes. Moreover, during feedback calculation, the value of the integral term in the second opening degree calculation is maintained or suppressed, dynamically limiting the range of the integral cumulative value of the integral term, so that the feedback opening degree of the three-way valve can quickly respond to temperature changes, thereby further stabilizing the control of the coolant temperature at the inlet of the fuel cell stack.

[0037] In some embodiments, the cooling control method further includes maintaining or suppressing the integral cumulative value of the previous moment of the integral term of the difference with respect to time, such that the target opening degree of the three-way valve 13 at the current moment determined based on the first opening degree and the processed second opening degree of the three-way valve 13 at the current moment does not exceed the allowable opening range.

[0038] Specifically, the allowable opening range is the maximum limit value of the opening degree of the three-way valve 13, for example, 100% of the opening degree of the three-way valve 13, that is, fully open, but not limited thereto.

[0039] In some embodiments, in the cooling control method, maintaining or suppressing the integral cumulative value of the previous moment of the integral term of the difference with respect to time according to the sum of the first opening degree and the second opening degree of the three-way valve 13 at the current moment specifically includes: when the sum of the first opening degree and the second opening degree at the current moment does not exceed the allowable opening range, not changing the integral cumulative value of the previous moment of the integral term of the difference and determining the target opening degree of the three-way valve 13 at the current moment based thereon.

[0040] Specifically, when the target opening degree of the three-way valve 13 is greater than or equal to the minimum limit value of the opening degree of the three-way valve 13 and less than or equal to the maximum limit value of the opening degree of the three-way valve 13, it is considered that the value of the integral term of the difference with respect to time is within a reasonable range at this time, so the value of the integral term is kept unchanged.

[0041] Exemplarily, the second opening degree D of the three-way valve 13 at each moment t can be determined by the following formula (1) fb :

[0042]

[0043] where D fb is the second opening degree of the three-way valve, e(t) is the difference between the target value and the measured value of the coolant temperature at the inlet of the fuel cell stack 11, k p is the proportional coefficient of the difference between the target value and the measured value, k iis the integral coefficient of the difference between the target value and the measured value, dt is the time constant of integration, and t is the current moment for calculating the second opening degree of the three-way valve.

[0044] In the case of, make the value of remain unchanged. Among them, D ff is the first opening degree, 0% and 100% respectively represent the minimum limit value and the maximum limit value of the opening degree of the three-way valve 13, and t - 1 is the previous moment of the current moment for calculating the second opening degree of the three-way valve.

[0045] In some embodiments, in the cooling control method, according to the sum of the first opening degree and the second opening degree of the three-way valve 13 at the current moment, the process of maintaining or suppressing the integral cumulative value of the previous moment of the integral term of the difference with respect to the moment specifically includes: when the integral cumulative value of the previous moment of the integral term of the difference with respect to the moment is zero but the sum of the first opening degree and the second opening degree at the current moment still exceeds the allowable opening range, clear the integral cumulative value of the previous moment of the integral term of the difference with respect to the moment.

[0046] Specifically, when the target opening degree obtained by adding the value of the first opening degree and the proportional term is greater than the maximum limit value of the opening degree of the three-way valve 13 or less than the minimum limit value of the opening degree of the three-way valve 13, that is, even if the value of the integral term at the current moment is not considered, the target opening degree of the three-way valve 13 has exceeded the positive feedback limit or the negative feedback limit, then it is considered that the next time the value of the integral term is needed, it will be negative feedback or positive feedback. Since clearing the current feedback cumulative value is beneficial to entering the reverse feedback as soon as possible, the value of the integral term accumulated to the previous moment is cleared according to the idea of minimizing the integral as much as possible.

[0047] Exemplarily, in D ff + k p * e(t) > 100% or D ff + k p * e(t) < 0% in the case of, make Among them, 0% and 100% respectively represent the minimum limit value and the maximum limit value of the opening degree of the three-way valve 13.

[0048] In some embodiments, in the cooling control method, the process of maintaining or suppressing the previous integral cumulative value of the integral term of the difference with respect to time according to the sum of the first opening degree and the second opening degree of the three-way valve 13 at the current moment specifically includes: when the sum of the first opening degree and the second opening degree at the current moment without considering the integral cumulative value of the integral term of the difference with respect to time does not exceed the allowable opening range, but the sum of the first opening degree and the second opening degree at the current moment considering the integral cumulative value of the integral term of the difference with respect to time exceeds the allowable opening range, replacing the previous integral cumulative value of the integral term of the difference with the boundary value such that the calculated target opening degree does not exceed the allowable opening range.

[0049] Specifically, when feedback of the integral term is required for the sum of the first opening degree and the second opening degree to exceed the maximum limit value of the opening degree of the three-way valve 13 or be less than the minimum limit value of the opening degree of the three-way valve 13, the value of the integral term accumulated to the previous moment is replaced with a minimum value that enables the three-way valve 13 to reach the limit opening degree.

[0050] Exemplarily, in D ff +k p *e(t) < 100% and That is, when feedback of the integral term is required for the sum of the first opening degree and the second opening degree to exceed the maximum limit value of the opening degree of the three-way valve 13, the replacement value of the value of the integral term accumulated to the previous moment is calculated by the following formula (2):

[0051]

[0052] In D ff +k p *e(t) > 0% and That is, when feedback of the integral term is required for the sum of the first opening degree and the second opening degree to be less than the minimum limit value of the opening degree of the three-way valve 13, the replacement value of the value of the integral term accumulated to the previous moment is calculated by the following formula (3):

[0053]

[0054] Wherein, 0% and 100% respectively represent the minimum limit value and the maximum limit value of the opening degree of the three-way valve 13.

[0055] In some embodiments, determining the second opening degree of the three-way valve 13 at each moment based on the proportional term and the integral term with respect to time of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack 11 specifically includes: determining the second opening degree of the three-way valve 13 based on the sum of the proportional term of the difference and the integral term of the difference with respect to time.

[0056] Exemplarily, when it is determined that the current operating state meets the allowable conditions for the feedback regulation of the three-way valve 13, the second opening degree D of the three-way valve 13 can be calculated by the above formula (1). fb .

[0057] In some embodiments, the proportional term of the difference has a proportional coefficient and the integral term of the difference with respect to time has an integral coefficient.

[0058] Exemplarily, as shown in formula (1), in the proportional term k p *e(t) of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack 11, there is a proportional coefficient k p of the difference. In the integral term of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack 11 with respect to time t, there is an integral coefficient k i of the difference.

[0059] In some embodiments, the cooling control method further includes: when the current operating state of the fuel cell system 1 does not meet the allowable conditions for the feedback regulation of the three-way valve 13, setting the second opening degree to a fixed value; when the current operating state of the fuel cell system 1 meets the allowable conditions for the feedback regulation of the three-way valve 13 again, re-integrating the integral term of the difference from zero.

[0060] Specifically, when it is determined that the current operating state does not meet the allowable conditions for the feedback regulation of the three-way valve 13, it is considered that the opening degree of the three-way valve 13 in the current operating state of the fuel cell system 1 does not need to be adjusted by the feedback of the integral term. Therefore, the second opening degree is set to zero or other fixed values, and the target opening degree of the three-way valve 13 at the current moment is calculated accordingly. When it is determined again that the current operating state of the fuel cell system 1 meets the allowable conditions for the feedback regulation of the three-way valve 13, the integral term is re-integrated from zero, and the target opening degree of the current three-way valve 13 is calculated accordingly.

[0061] In some embodiments, the cooling control method further includes determining the proportional coefficient and the integral coefficient at each moment. Figure 3 FIG. is a flowchart for determining the proportional coefficient and the integral coefficient according to an embodiment of the present application. As Figure 3 shown, the cooling control method includes using the controller 19 to perform the processes of the following steps S201 to S202:

[0062] In step S201, obtain the correlation relationship between the different differences between the measured value of the coolant temperature at the inlet of the stack 11 and the measured value of the coolant temperature at the outlet of the radiator 15, the proportional coefficient, and the integral coefficient.

[0063] In step S202, according to the difference between the measured value of the coolant temperature at the inlet of the stack 11 and the measured value of the coolant temperature at the outlet of the radiator 15 at each moment, the proportionality coefficient and the integral coefficient at the corresponding moment are determined with reference to the correlation relationship, so as to determine the second opening degree at each moment.

[0064] As Figure 4 shown, the proportionality coefficient k p and the integral coefficient k i values change with the temperature difference between the measured value of the coolant temperature at the inlet of the stack 11 and the measured value of the coolant temperature at the outlet of the radiator 15. By calculating the temperature difference between the actual coolant temperature at the inlet of the stack 11 and the actual coolant temperature at the outlet of the radiator 15 at each moment and performing one-dimensional look-up table, the k p and k i values at the temperature difference at each moment are obtained, so that when the temperature difference between the actual coolant temperature at the outlet of the radiator 15 and the actual coolant temperature at the inlet of the stack 11 changes, the accurate k p and k i coefficients corresponding to the current temperature difference are used for calculation, improving the accuracy of feedback control, achieving a better feedback control effect, and further making the coolant temperature more accurate and stable.

[0065] In some embodiments, for the cooling control method, the correlation relationship between different differences between the measured value of the coolant temperature at the inlet of the stack 11 and the measured value of the coolant temperature at the outlet of the radiator 15 and the proportionality coefficient and the integral coefficient includes a table of the proportionality coefficient and the integral coefficient under different differences between the measured value of the coolant temperature at the inlet of the stack 11 and the measured value of the coolant temperature at the outlet of the radiator 15 measured in advance through experiments.

[0066] Specifically, by obtaining the numerical correspondence table between the temperature difference between the measured value of the coolant temperature at the inlet of the stack 11 and the measured value of the coolant temperature at the outlet of the radiator 15 and the K values of the proportionality coefficient and the integral coefficient, the correlation relationship between different temperature differences and the proportionality coefficient and the integral coefficient is obtained. The proportionality coefficient k p and the integral coefficient k i are defined as the one-dimensional look-up table values according to the temperature difference between the measured value of the coolant temperature at the inlet of the stack 11 and the measured value of the coolant temperature at the outlet of the radiator 15, and the look-up table values of k p and k i can be obtained through experimental tests.

[0067] In some embodiments of the present application, a fuel cell system 1 is provided. As Figure 1As shown, the fuel cell system 1 includes a fuel cell stack 11, a three-way valve 13, a radiator 15, a fan 14, a pump 12, and a controller 19. The coolant from the outlet of the pump 12 is fed to the fuel cell stack 11. After flowing through the fuel cell stack 11, the coolant is fed to the inlet of the three-way valve 13. The first outlet of the three-way valve 13 communicates with the inlet of the radiator 15, and the second outlet communicates with the outlet of the radiator 15 and the inlet of the pump 12. The fan 14 is used to cool the coolant flowing through the radiator 15. The controller 19 is configured to execute the cooling control method of the fuel cell system 1 according to various embodiments of the present application.

[0068] The heat dissipation part 20 in the fuel cell system 1 is configured to include a fan 14 and a radiator 15. Moreover, the fuel cell system 1 further includes a coolant temperature sensor 16 at the inlet of the fuel cell stack, a coolant temperature sensor 17 at the outlet of the fuel cell stack, and a coolant temperature sensor 18 at the outlet of the radiator, which are respectively used to detect the measured value of the coolant temperature at the inlet of the fuel cell stack 11, the measured value of the coolant temperature at the outlet of the fuel cell stack 11, and the measured value of the coolant temperature at the outlet of the radiator 15.

[0069] In Example 2 of the embodiments of the present application, the fuel cell system 1, especially the controller 19, executes the cooling control method of the fuel cell system 1 according to various embodiments of the present application. Figure 5 The flowchart of the cooling control method of the fuel cell system according to Example 2 of the embodiments of the present application is shown. As Figure 5 shown, the process of Example 2 includes steps S501 to S507.

[0070] In step S501, the first opening degree of the three-way valve at the current moment is calculated. The first opening degree can be calculated by using one or more of the target value of the coolant temperature at the inlet of the fuel cell stack 11, the measured value of the coolant temperature at the outlet of the fuel cell stack 11, and the measured value of the coolant temperature at the outlet of the radiator 15, or can also be obtained by looking up a table according to one or more of these three values.

[0071] In step S502, it is judged whether the current operating state of the fuel cell system meets the allowable conditions for the feedback regulation of the three-way valve. The current operating state of the fuel cell system 1 is identified through the operating state signal. When the current operating state of the fuel cell system 1 is the power generation process, it is judged that the current operating state meets the allowable conditions for the feedback regulation of the three-way valve, and step S503 is entered. When the current operating state of the fuel cell system 1 is any one of the startup, shutdown, and rapid warm-up processes, it is judged that the current operating state does not meet the allowable conditions for the feedback regulation of the three-way valve, and step S505 is entered.

[0072] In step S503, the second opening degree of the three-way valve at the current moment is calculated. Exemplarily, the second opening degree D of the three-way valve 13 at each moment t is calculated by using Equation (1). fb:

[0073]

[0074] Among them, D fb is the second opening degree of the three-way valve, e(t) is the difference between the target value and the measured value of the coolant temperature at the inlet of the fuel cell stack 11, k p is the proportional coefficient of the difference between the target value and the measured value, k i is the integral coefficient of the difference between the target value and the measured value, dt is the time constant of integration, and t is the current moment for calculating the second opening degree of the three-way valve.

[0075] In step S504, the second opening degree of the three-way valve at the current moment is output. The output is the second opening degree D obtained by calculating using the above formula (1) fb as the calculation result of the three-way valve feedback regulation.

[0076] In step S505, the second opening degree of the three-way valve at the current moment is set to a fixed value and the integral term is set to zero. In the case of not performing the three-way valve feedback regulation, the second opening degree D at the current moment fb is set to a fixed value, and the value of the integral term of the difference between the target value and the measured value of the coolant temperature at the inlet of the fuel cell stack 11 with respect to time is set to zero.

[0077] In step S506, the second opening degree of the three-way valve at the current moment and the value of the integral term are output. The output is the second opening degree D set to a fixed value fb , so that the subsequent calculation of the target opening degree of the three-way valve is not affected by the three-way valve feedback regulation, and the value of the integral term set to zero is output to minimize the cumulative value of the integral term.

[0078] In step S507, the target opening degree of the three-way valve at the current moment is calculated. Exemplarily, according to the sum of the first opening degree and the second opening degree of the three-way valve 13 at the current moment, the method for maintaining or suppressing the previous integral cumulative value of the integral term of the difference with respect to time mentioned in any embodiment of the previous cooling control method of a fuel cell system is used to determine the processed second opening degree of the three-way valve 13 at the current moment, and based on the first opening degree and the processed second opening degree of the three-way valve 13 at the current moment, the target opening degree of the three-way valve 13 at the current moment is determined.

[0079] The controller 19 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 method of various embodiments of the present application can be selectively combined here, and will not be elaborated here.

[0080] The cooling control method and fuel cell system of the present application set the allowable conditions for feedback regulation, and perform feedback calculations only when the allowable conditions are met, avoiding unnecessary integral operations in some operating states, thereby avoiding sudden changes in the opening degree of the three-way valve when the operating state of the fuel cell system changes. Moreover, during the feedback calculation, the value of the integral term in the second opening calculation is maintained or suppressed, dynamically limiting the range of the integral cumulative value of the integral term, so that the feedback opening of the three-way valve can quickly respond to temperature changes, thereby further stabilizing the control of the coolant temperature at the inlet of the fuel cell stack.

[0081] In addition, although exemplary embodiments have been described herein, the scope includes any and all embodiments based on the present disclosure having equivalent elements, modifications, omissions, combinations (e.g., schemes that cross various embodiments), adaptations, or alterations. The elements in the claims will be broadly interpreted based on the language employed in the claims and are not limited to the examples described in this specification or during the implementation of the present application, and the examples will be interpreted as non-exclusive. Thus, the specification and examples are intended to be considered only as examples, and the true scope and spirit are indicated by the following claims and the full scope of their equivalents.

[0082] The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more of them) can be used in combination with each other. For example, those of ordinary skill in the art can use other embodiments when reading the above description. Additionally, in the above detailed description, various features can be grouped together to simplify the present disclosure. This should not be construed as an intention that a disclosed feature not claimed is necessary for any claim. On the contrary, the subject matter of the present invention can be less than all the features of a particular disclosed embodiment. Thus, the following claims are incorporated herein as examples or embodiments into the detailed description, where each claim stands alone as a separate embodiment, and considering these embodiments can be combined with each other in various combinations or permutations. The scope of the present invention should be determined with reference to the appended claims and the full scope of the equivalents to which those claims are entitled.

Claims

1. A cooling control method for a fuel cell system, the fuel cell system comprising a stack, a three-way valve, a radiator, a fan, a pump, and a controller, characterized in that, The described cooling control method includes having the controller perform the following processes: Based on the target value of the coolant temperature at the inlet of the stack, the measured value of the coolant temperature at the outlet of the stack, and the measured value of the coolant temperature at the outlet of the radiator, determine the first opening degree of the three-way valve at each moment; When the current operating state of the fuel cell system meets the allowable conditions for the feedback regulation of the three-way valve, based on the proportional term of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack and the integral term with respect to time, determine the second opening degree of the three-way valve at each moment; And, According to the sum of the first opening degree and the second opening degree of the three-way valve at the current moment, perform a process of maintaining or suppressing the integral cumulative value of the previous moment of the integral term of the difference with respect to time, then determine the processed second opening degree of the three-way valve at the current moment based on this, and based on the first opening degree and the processed second opening degree of the three-way valve at the current moment, determine the target opening degree of the three-way valve at the current moment.

2. The cooling control method according to claim 1, wherein It further includes: Perform a process of maintaining or suppressing the integral cumulative value of the previous moment of the integral term of the difference with respect to time, such that the target opening degree of the three-way valve at the current moment determined based on the first opening degree and the processed second opening degree of the three-way valve at the current moment does not exceed the allowable opening range.

3. The cooling control method according to claim 1, wherein The process of maintaining or suppressing the integral cumulative value of the previous moment of the integral term of the difference with respect to time according to the sum of the first opening degree and the second opening degree of the three-way valve at the current moment specifically includes: when the sum of the first opening degree and the second opening degree at the current moment does not exceed the allowable opening range, do not change the integral cumulative value of the previous moment of the integral term of the difference and determine the target opening degree of the three-way valve at the current moment based on this.

4. The cooling control method according to claim 1, wherein The process of maintaining or suppressing the integral cumulative value of the previous moment of the integral term of the difference with respect to time according to the sum of the first opening degree and the second opening degree of the three-way valve at the current moment specifically includes: when the integral cumulative value of the previous moment of the integral term of the difference is zero but the sum of the first opening degree and the second opening degree at the current moment still exceeds the allowable opening range, clear the integral cumulative value of the previous moment of the integral term of the difference.

5. The cooling control method according to claim 1, wherein The process of maintaining or suppressing the integral cumulative value of the previous moment of the integral term of the difference with respect to time according to the sum of the first opening degree and the second opening degree of the three-way valve at the current moment specifically includes: when the sum of the first opening degree and the second opening degree at the current moment does not exceed the allowable opening range without considering the integral cumulative value of the current moment of the integral term of the difference, but exceeds the allowable opening range when considering the integral cumulative value of the current moment of the integral term of the difference, replace the integral cumulative value of the previous moment of the integral term of the difference with the boundary value such that the calculated target opening degree does not exceed the allowable opening range.

6. The cooling control method according to claim 1, characterized in that Determining the second opening degree of the three-way valve at each moment based on the proportional term of the difference between the target value and the measured value of the coolant temperature at the inlet of the stack and the integral term with respect to time specifically includes: determining the second opening degree of the three-way valve based on the sum of the proportional term of the difference and the integral term of the difference with respect to time.

7. The cooling control method according to claim 1, characterized in that The proportional term of the difference has a proportional coefficient and the integral term of the difference with respect to time has an integral coefficient.

8. The cooling control method according to claim 6 or 7, characterized in that It further includes: When the current operating state of the fuel cell system does not meet the allowable conditions for the feedback regulation of the three-way valve, setting the second opening degree to a fixed value, and when the current operating state of the fuel cell system meets the allowable conditions for the feedback regulation of the three-way valve again, restarting the integration of the integral term of the difference with respect to time from zero.

9. The cooling control method according to claim 7, wherein It further includes: Obtaining the correlation relationship between the different differences between the measured value of the coolant temperature at the inlet of the stack and the measured value of the coolant temperature at the outlet of the radiator and the proportional coefficient and the integral coefficient; According to the difference between the measured value of the coolant temperature at the inlet of the stack and the measured value of the coolant temperature at the outlet of the radiator at each moment, referring to the correlation relationship to determine the proportional coefficient and the integral coefficient at the corresponding moment for determining the second opening degree at each moment.

10. The cooling control method according to claim 9, characterized in that, The correlation relationship between the different differences between the measured value of the coolant temperature at the inlet of the stack and the measured value of the coolant temperature at the outlet of the radiator and the proportional coefficient and the integral coefficient includes a table of the proportional coefficient and the integral coefficient under different differences between the measured value of the coolant temperature at the inlet of the stack and the measured value of the coolant temperature at the outlet of the radiator measured in advance through experiments.

11. A fuel cell system, characterized in that, It includes a stack, a three-way valve, a radiator, a fan, a pump, and a controller. 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 controller is configured to execute the cooling control method of the fuel cell system according to any one of claims 1-10.

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