Fuel cell overheat prevention control system and method

Abstract

A fuel cell that generates electricity through the reaction of a fuel gas and an oxidizing gas; a cooling line connected to the fuel cell such that a cooling medium flows inside and the flowing cooling medium exchanges heat with the fuel cell; a cooling pump provided in the cooling line and circulating the cooling medium inside the cooling line when operating; a cooling controller that controls the operation of the cooling pump based on the temperature of the fuel cell or the temperature of the cooling medium; and a power generation controller that limits the power generation of the fuel cell based on the operation state of the cooling pump; are introduced.

Description

Technology Field

[0001] The present invention relates to a control system and method for preventing overheating of a fuel cell, and more specifically, to a technology for preventing overheating of a fuel cell by limiting the power generation of the fuel cell based on the operating state of a cooling pump that circulates cooling water. Background Technology

[0003] A fuel cell is a type of power generation device that directly converts chemical energy generated by the oxidation of fuel into electrical energy. While fundamentally similar to chemical batteries in that they utilize oxidation and reduction reactions, they differ in that, unlike chemical batteries which conduct reactions within a closed system, reactants are continuously supplied from the outside, and reaction products are continuously removed from the system. Recently, fuel cell power generation systems have been commercialized, and active research is being conducted to utilize them as an energy source for eco-friendly vehicles, as the reaction product of fuel cells is pure water.

[0004] A fuel cell system includes a fuel cell stack that generates electrical energy through a chemical reaction, an air supply device that supplies air to the cathode of the fuel cell stack, and a hydrogen supply device that supplies hydrogen to the anode of the fuel cell stack. In other words, air containing oxygen is supplied to the cathode of the fuel cell stack, and hydrogen is supplied to the anode of the fuel cell stack.

[0005] Fuel cell stacks have hardware characteristics that make them less resistant to thermal damage compared to conventional internal combustion engines. Due to this poor resistance to thermal damage, fail-safe strategies that control-wise diagnose and respond to fuel cell stack overheating are emerging as a very important aspect.

[0006] Generally, fuel cell cooling control is performed based on the temperature of the cooling water at the fuel cell stack outlet because it is difficult to directly sense the internal temperature of the fuel cell stack. Therefore, there was a problem in that it became impossible to prevent fuel cell stack overheating when a malfunction occurred in the temperature sensor sensing the temperature of the cooling water at the fuel cell stack outlet.

[0008] The matters described above as background technology are intended only to enhance understanding of the background of the present invention and should not be construed as an acknowledgment that they constitute prior art already known to those skilled in the art. Prior art literature

[0010] KR 10-16285141 B The problem to be solved

[0011] The present invention is proposed to solve these problems and aims to provide a technology that prevents overheating of a fuel cell by limiting the power generation of the fuel cell based on the operating state of a cooling pump that circulates cooling water for cooling the fuel cell. means of solving the problem

[0013] A fuel cell overheating prevention control system according to the present invention for achieving the above objective comprises: a fuel cell that generates power through the reaction of a fuel gas and an oxidizing gas; a cooling line connected to the fuel cell such that a cooling medium flows inside and the flowing cooling medium exchanges heat with the fuel cell; a cooling pump provided in the cooling line and circulating the cooling medium inside the cooling line when operated; a cooling controller that controls the operation of the cooling pump based on the temperature of the fuel cell or the temperature of the cooling medium; and a power generation controller that limits the power generation of the fuel cell based on the operation state of the cooling pump.

[0014] The cooling line is equipped with a radiator that exchanges heat between the internal cooling medium and the outside, and the cooling line is extended so that the inlet and outlet of the fuel cell circulate with the radiator, and the cooling pump can flow part or all of the cooling medium discharged through the outlet of the fuel cell to the radiator, or flow the cooling medium discharged from the radiator to the inlet of the fuel cell.

[0015] The cooling controller further includes a temperature sensor located on the outlet side of the fuel cell in the cooling line and sensing the temperature of the cooling medium flowing inside, and the cooling controller can control the operation of the cooling pump based on the temperature of the cooling medium sensed by the temperature sensor.

[0016] The cooling controller controls the cooling pump to follow a rotational speed command set based on the temperature of the fuel cell or the temperature of the cooling medium, and the power generation controller can limit the power generation of the fuel cell based on the speed deviation, which is the difference between the rotational speed command of the cooling pump and the actual rotational speed.

[0017] The power generation controller limits the power generation of the fuel cell to below a preset power generation limit based on the temperature of the fuel cell or the temperature of the cooling medium, and can apply a first offset set based on the speed deviation to the temperature of the fuel cell or the temperature of the cooling medium, or to the power generation limit.

[0018] The power generation controller can set the first offset to gradually reduce the temperature of the fuel cell or cooling medium that limits the power generation of the fuel cell as the magnitude of the speed deviation increases when the speed deviation is greater than or equal to a preset speed deviation value, or to gradually reduce the power generation limit value.

[0019] The power generation controller can limit the power generation of the fuel cell based on the power deviation, which is the difference between the preset power consumption and the actual power consumption of the cooling pump according to the rotational speed of the cooling pump.

[0020] The power generation controller can limit the power generation of the fuel cell based on the power deviation only when the rotational speed of the cooling pump is greater than or equal to a preset rotational speed.

[0021] The power generation controller limits the power generation of the fuel cell to below a preset power generation limit based on the temperature of the fuel cell or the temperature of the cooling medium, and if the actual power consumption of the cooling pump is below the preset power consumption, it may apply a second offset set based on the power deviation to the temperature of the fuel cell or the temperature of the cooling medium or to the power generation limit.

[0022] The power generation controller can set the second offset to gradually reduce the temperature of the fuel cell or cooling medium that limits the power generation of the fuel cell as the magnitude of the power deviation increases when the power deviation is greater than or equal to a preset power deviation value, or to gradually reduce the power generation limit value.

[0023] The cooling controller can increase the cooling amount of the cooling pump based on the power deviation when the actual power consumption of the cooling pump is greater than the preset power consumption.

[0025] A method for controlling the prevention of overheating of a fuel cell according to the present invention for achieving the above objective comprises: a step of estimating the temperature of the fuel cell or sensing the temperature of a cooling medium; a step of controlling the operation of a cooling pump that circulates a cooling medium flowing into a cooling line connected to the fuel cell based on the estimated temperature of the fuel cell or the sensed temperature of the cooling medium; and a step of limiting the power generation of the fuel cell based on the operation state of the cooling pump.

[0026] In the step of controlling the operation of the cooling pump, the cooling pump is controlled to follow a rotational speed command set based on the temperature of the fuel cell or the temperature of the cooling medium, and prior to the step of limiting the power generation of the fuel cell, the method further includes a step of calculating a speed deviation, which is the difference between the rotational speed command of the cooling pump and the actual rotational speed; and in the step of limiting the power generation of the fuel cell, the power generation of the fuel cell can be limited based on the calculated speed deviation.

[0027] In the step of limiting the power generation of the fuel cell, the power generation of the fuel cell is limited to a power generation limit below a preset limit based on the temperature of the fuel cell or the temperature of the cooling medium, and a first offset set based on the speed deviation can be applied to the temperature of the fuel cell or the temperature of the cooling medium, or to the power generation limit.

[0028] Prior to the step of limiting the power generation of the fuel cell, the method further includes a step of calculating a power deviation, which is the difference between the power consumption preset according to the rotational speed of the cooling pump and the actual power consumption of the cooling pump; and in the step of limiting the power generation of the fuel cell, the power generation of the fuel cell can be limited based on the calculated power deviation.

[0029] In the step of limiting the power generation of the fuel cell, the power generation of the fuel cell is limited to a preset power generation limit or lower depending on the temperature of the fuel cell or the temperature of the cooling medium, and if the actual power consumption of the cooling pump is less than or equal to the preset power consumption, a second offset set based on the power deviation can be applied to the temperature of the fuel cell or the temperature of the cooling medium or to the power generation limit.

[0030] After the step of calculating the power deviation, if the actual power consumption of the cooling pump is greater than the preset power consumption, the method may further include a step of increasing the cooling amount of the cooling pump based on the power deviation. Effects of the invention

[0032] According to the fuel cell overheating prevention control system and method of the present invention, by reflecting the operating state of the cooling pump, it has the effect of preventing overheating of the fuel cell even if an error occurs in the temperature of the fuel cell or the temperature of the cooling medium. Brief explanation of the drawing

[0034] FIG. 1 is a configuration diagram of a fuel cell overheating prevention control system according to one embodiment of the present invention. FIG. 2 illustrates a graph of the first offset according to the speed deviation according to one embodiment of the present invention. Figure 3 shows a graph of power consumption according to the rotational speed of a cooling pump according to one embodiment of the present invention. FIG. 4 illustrates a graph of the second offset according to the power deviation according to one embodiment of the present invention. FIG. 5 illustrates a graph of a current limiting standard that varies according to the temperature of a cooling medium according to one embodiment of the present invention. FIG. 6 is a flowchart of a method for preventing overheating of a fuel cell according to one embodiment of the present invention. Specific details for implementing the invention

[0035] Specific structural or functional descriptions of embodiments of the present invention disclosed in this specification or application are merely illustrative for the purpose of explaining embodiments according to the present invention, and embodiments according to the present invention may be implemented in various forms and should not be interpreted as being limited to the embodiments described in this specification or application.

[0036] Since embodiments according to the present invention may be subject to various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in this specification or application. However, this is not intended to limit embodiments according to the concept of the present invention to specific disclosed forms, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention.

[0037] Terms such as "first" and / or "second" may be used to describe various components, but said components shall not be limited by said terms. For the sole purpose of distinguishing one component from another, for example, without departing from the scope of rights according to the concept of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0038] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. Conversely, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between. Other expressions describing the relationship between components, such as "between" and "exactly between," or "adjacent to" and "directly adjacent to," should be interpreted in the same way.

[0039] The terms used herein are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to specify the existence of the described features, numbers, steps, actions, components, parts, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0040] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this specification.

[0041] The present invention will be described in detail below by explaining preferred embodiments of the invention with reference to the attached drawings. Identical reference numerals in each drawing indicate identical components.

[0042] FIG. 1 is a configuration diagram of an overheat prevention control system for a fuel cell (10) according to one embodiment of the present invention.

[0043] Referring to FIG. 1, an overheat prevention control system for a fuel cell (10) according to one embodiment of the present invention comprises: a fuel cell (10) that generates power through the reaction of a fuel gas and an oxidizing gas; a cooling line (20) connected to the fuel cell (10) such that a cooling medium flows inside and the flowing cooling medium exchanges heat with the fuel cell (10); a cooling pump (30) provided in the cooling line (20) and circulating the cooling medium inside the cooling line (20) when operated; a cooling controller (40) that controls the operation of the cooling pump (30) based on the temperature of the fuel cell (10) or the temperature of the cooling medium; and a power generation controller (50) that limits the power generation of the fuel cell (10) based on the operation state of the cooling pump (30).

[0044] A cooling controller (40) and a generator controller (50) according to an exemplary embodiment of the present invention may be implemented through a non-volatile memory (not shown) configured to store data regarding an algorithm configured to control the operation of various components of a vehicle or software instructions for reproducing said algorithm, and a processor (not shown) configured to perform the operation described below using the data stored in said memory. Here, the memory and the processor may be implemented as separate chips. Alternatively, the memory and the processor may be implemented as a single chip integrated with each other. The processor may take the form of one or more processors.

[0045] The fuel cell (10) can receive fuel gas and oxidizing gas to the anode and cathode, respectively. Here, the fuel gas may be hydrogen gas, and the oxidizing gas may be air containing oxygen. The fuel cell (10) can generate electrical energy and thermal energy through a chemical reaction between hydrogen and oxygen.

[0046] The cooling line (20) is a line through which a cooling medium flows, and water-cooled cooling can be adopted in which the cooling medium is water. The cooling medium flows inside the cooling line (20), enters the inlet of the fuel cell (10), passes through the fuel cell (10), and can be discharged through the outlet of the fuel cell (10).

[0047] The cooling pump (30) is provided in the cooling line (20) and can flow a cooling medium when driven. In particular, the amount of flow of the cooling medium can be controlled as the rotational speed is controlled by the cooling controller (40).

[0048] The cooling controller (40) can control the operation of the cooling pump (30) based on the temperature of the fuel cell (10) or the temperature of the cooling medium. In one embodiment, the cooling controller (40) can control the cooling pump (30) so that the flow rate of the cooling medium increases as the temperature of the fuel cell (10) or the temperature of the cooling medium rises.

[0049] Additionally, the cooling controller (40) can control the control valve to control the flow rate of the cooling medium passing through the radiator (21) described later.

[0050] The power generation controller (50) controls the power generation of the fuel cell (10) and can limit the power generation of the fuel cell (10) based on the operating state of the cooling pump (30). In particular, the power generation controller (50) can limit the output current of the fuel cell (10) or the output power of the fuel cell (10).

[0051] More specifically, the power generation controller (50) can limit the magnitude of the output current of the fuel cell (10) or the output power of the fuel cell (10) based on the temperature of the fuel cell (10) or the temperature of the cooling medium. In one embodiment, the output current of the fuel cell (10) can be limited to a preset limiting current or less for each temperature of the fuel cell (10) or the temperature of the cooling medium.

[0052] In particular, the power generation controller (50) according to the present invention can vary the preset limiting current that limits the output current of the fuel cell (10) according to the driving state of the cooling pump (30).

[0053] Accordingly, according to the present invention, by reflecting the operating state of the cooling pump (30), it has the effect of preventing overheating of the fuel cell (10) even if an error occurs in the temperature of the fuel cell (10) or the temperature of the cooling medium.

[0054] A cooling line (20) is provided with a radiator (21) that exchanges heat between the internal cooling medium and the outside, and the cooling line (20) is extended so that the inlet and outlet of the fuel cell (10) circulate with the radiator (21), and a cooling pump (30) can flow part or all of the cooling medium discharged through the outlet of the fuel cell (10) to the radiator (21), or flow the cooling medium discharged from the radiator (21) to the inlet of the fuel cell (10).

[0055] The heat exchanger (21) may be a device that exchanges heat with the outside air for the cooling medium inside the cooling line (20), such as a radiator.

[0056] The cooling controller (40) further includes a temperature sensor (22) located at the outlet side of the fuel cell (10) in the cooling line (20) and sensing the temperature of the cooling medium flowing inside, and the cooling controller (40) can control the operation of the cooling pump (30) based on the temperature of the cooling medium sensed by the temperature sensor (22).

[0057] That is, the temperature of the cooling medium is distributed differently depending on the location of the cooling line (20), but the temperature sensor (22) can sense the temperature of the cooling medium discharged from the outlet of the fuel cell (10) in the cooling line (20).

[0058] In addition, in the present invention, the temperature of the fuel cell (10) can be estimated based on the temperature of the cooling medium. In particular, the temperature of the fuel cell (10) can be estimated based on the temperature of the cooling medium on the outlet side of the fuel cell (10) sensed by the temperature sensor (22).

[0059] In one embodiment, the cooling controller (40) can control the rotational speed of the cooling pump (30) to increase as the temperature of the sensed cooling medium or the estimated temperature of the fuel cell (10) rises.

[0061] FIG. 2 illustrates a graph of the first offset according to the speed deviation according to one embodiment of the present invention.

[0062] Referring further to FIG. 2, the cooling controller (40) controls the cooling pump (30) to follow a rotational speed command set based on the temperature of the fuel cell (10) or the temperature of the cooling medium, and the power generation controller (50) can limit the power generation of the fuel cell (10) based on the speed deviation, which is the difference between the rotational speed command of the cooling pump (30) and the actual rotational speed.

[0063] In one embodiment, the rotational speed command can be mapped to vary according to the temperature of the fuel cell (10) or the temperature of the cooling medium.

[0064] The generator controller (50) can calculate the speed deviation as the difference between the rotational speed command (RPM command) and the actual rotational speed (actual RPM) of the cooling pump (30) using the following formula.

[0065] △RPM = | RPM command - Actual RPM |

[0066] In another embodiment, the speed deviation can be calculated as (RPM command - actual RPM) rather than an absolute value, and the case where the actual RPM does not follow the RPM command and thus the cooling performance of the fuel cell (10) is not secured can be limited.

[0067] The power generation controller (50) can limit the power generation of the fuel cell (10) based on the calculated speed deviation. In particular, the power generation controller (50) can set a first offset applied to a preset power generation limit value that limits the power generation of the fuel cell (10) according to the calculated speed deviation.

[0068] More specifically, the power generation controller (50) limits the power generation of the fuel cell (10) to a level below a preset power generation limit based on the temperature of the fuel cell (10) or the temperature of the cooling medium, and can apply a first offset set based on the speed deviation to the temperature of the fuel cell (10) or the temperature of the cooling medium, or to the power generation limit.

[0069] The generator controller (50) is a first offset ( When the speed deviation is greater than a preset speed deviation value, the temperature of the fuel cell (10) or the cooling medium that gradually limits the power generation of the fuel cell (10) as the magnitude of the speed deviation increases can be reduced, or the power generation limit value can be gradually reduced.

[0070] In other words, the generator controller (50) is, the first offset ( ) can be set so that when the speed deviation is greater than or equal to a preset speed deviation value, the size gradually increases as the size of the speed deviation increases.

[0071] That is, the first offset ( As shown in FIG. 2, the speed deviation is set to 0 when the speed deviation is less than or equal to a preset speed deviation value (A), and when the speed deviation is greater than or equal to the preset speed deviation value (A), the size can be set to gradually increase as the size of the speed deviation increases.

[0072] In particular, the first offset ( ) can be set to a negative value less than 0.

[0074] FIG. 3 illustrates a graph of power consumption according to the rotational speed of a cooling pump (30) according to one embodiment of the present invention, and FIG. 4 illustrates a graph of a second offset according to the power deviation according to one embodiment of the present invention.

[0075] Referring to FIGS. 3 and 4, the power generation controller (50) can limit the power generation of the fuel cell (10) based on the power deviation, which is the difference between the power consumption preset according to the rotational speed of the cooling pump (30) and the actual power consumption of the cooling pump (30).

[0076] Specifically, the power deviation (△P) is the preset power consumption (reference power consumption, as follows) It can be calculated by subtracting the actual power consumption (P) from ). Here, the preset power consumption can be preset as the amount of power consumed when the cooling pump (30) is operated in a normal state at the corresponding rotational speed.

[0077] △P = - P

[0078] In particular, the generator controller (50) is used when the rotational speed of the cooling pump (30) is greater than or equal to a preset rotational speed ( Power generation of the fuel cell (10) can be limited based on the power deviation (△P) only when ≥ P, △P ≥ 0).

[0079] More specifically, the generator controller (50) sets a second offset based on the power deviation when the power deviation (△P) is greater than or equal to C, which is greater than 0. You can set ) and the set second offset ( The power generation of the fuel cell (10) can be limited by reflecting )

[0080] The power generation controller (50) limits the power generation of the fuel cell (10) to below a preset power generation limit based on the temperature of the fuel cell (10) or the temperature of the cooling medium, and when the actual power consumption of the cooling pump (30) is below the preset power consumption, a second offset (set based on the power deviation) ) can be applied to the temperature of the fuel cell (10) or the temperature of the cooling medium, or to the power generation limit.

[0081] As illustrated in FIG. 4, the generator controller (50) has a second offset ( When the power deviation (△P) is greater than or equal to a preset power deviation value (E), the temperature of the fuel cell (10) or the cooling medium that gradually limits the power generation of the fuel cell (10) as the magnitude of the power deviation (△P) increases can be reduced, or the power generation limit value can be gradually reduced.

[0082] Or, the generator controller (50) is a second offset ( ) can be set so that when the power deviation (△P) is greater than or equal to the preset power deviation value (E), the size of the power deviation (△P) gradually increases as the size of the power deviation (△P) increases.

[0083] Here, the second offset ( ) can be set to a negative value less than 0.

[0084] Additionally, the generator controller (50) has a first offset ( ) and second offset( A final offset can be calculated based on ), and power generation of the fuel cell (10) can be controlled based on the calculated final offset. In one embodiment, the power generation controller (50) has a first offset ( ) and second offset( The final offset can be calculated by applying weights to each of the ).

[0085] The cooling controller (40) is used when the actual power consumption of the cooling pump (30) is greater than the preset power consumption ( < P, △P < 0) Based on the power deviation (△P), the amount of cooling that cools the cooling pump (30) can be increased.

[0086] In particular, the cooling controller (40) can increase the amount of cooling that cools the cooling pump (30) when the power deviation (△P) is smaller than D, which is preset to be smaller than 0.

[0087] Here, the cooling pump (30) can be cooled by a separate cooling water circulation or external air circulation, and the cooling controller (40) can increase the cooling amount of the cooling pump (30) by increasing the rotational speed of such an electric cooling pump or an electric radiator fan.

[0088] Additionally, the first offset ( ) or second offset( Each of ) is greater than or equal to a preset size, or the first offset ( ) or second offset( If the sum of ) is greater than the preset size, it is determined that the error is too large and cooling is impossible at all, so the power generation controller (50) can shut down the fuel cell (10).

[0090] FIG. 5 illustrates a graph of a current limiting standard that varies according to the temperature of a cooling medium according to one embodiment of the present invention.

[0091] Referring further to FIG. 5, the power generation controller (50) can limit the power generation of the fuel cell (10) to below a current limit standard that varies according to the temperature of the cooling medium.

[0092] In particular, when the temperature of the cooling medium is below a preset temperature, the current limit standard may be maintained, and when the temperature of the cooling medium is above the preset temperature, the current limit standard may be gradually reduced.

[0093] In one embodiment, the generator controller (50) has a first offset ( ) and the second offset( Temperature offset (summed of ) ) can be calculated, and the calculated temperature offset( ) can be applied to the temperature of the fuel cell (10) or the temperature of the cooling medium, or to the power generation limit.

[0094] More specifically, the generator controller (50) has a temperature offset (current limit reference graph that varies according to the temperature of the cooling medium). It can be moved by ) or, a temperature offset ( The current limiting standard can be varied by reflecting ).

[0095] In another embodiment, the generator controller (50) has a first offset ( ) and the second offset( Temperature offset (summed of ) The current limiting standard can be varied by applying ).

[0097] FIG. 6 is a flowchart of a method for preventing overheating of a fuel cell (10) according to one embodiment of the present invention.

[0098] Referring further to FIG. 6, a method for controlling the prevention of overheating of a fuel cell (10) according to one embodiment of the present invention comprises: a step (S100) of estimating the temperature of the fuel cell (10) or sensing the temperature of a cooling medium; a step (S200) of controlling the operation of a cooling pump (30) that circulates a cooling medium flowing into a cooling line (20) connected to the fuel cell (10) based on the estimated temperature of the fuel cell (10) or the sensed temperature of the cooling medium; and a step (S600) of limiting the power generation of the fuel cell (10) based on the operation state of the cooling pump (30).

[0099] In the step (S200) of controlling the operation of the cooling pump (30), the cooling pump (30) is controlled to follow a rotational speed command set based on the temperature of the fuel cell (10) or the temperature of the cooling medium, and prior to the step (S600) of limiting the power generation of the fuel cell (10), the method further includes a step (S300) of calculating a speed deviation, which is the difference between the rotational speed command of the cooling pump (30) and the actual rotational speed; and in the step (S600) of limiting the power generation of the fuel cell (10), the power generation of the fuel cell (10) can be limited based on the calculated speed deviation.

[0100] In the step (S600) of limiting the power generation of the fuel cell (10), the power generation of the fuel cell (10) is limited to a power generation limit value set according to the temperature of the fuel cell (10) or the temperature of the cooling medium, and a first offset set based on the speed deviation can be applied to the temperature of the fuel cell (10) or the temperature of the cooling medium, or to the power generation limit value.

[0101] Prior to the step (S600) of limiting the power generation of the fuel cell (10), the method further includes a step (S400) of calculating a power deviation, which is the difference between the power consumption preset according to the rotational speed of the cooling pump (30) and the actual power consumption of the cooling pump (30); and in the step (S600) of limiting the power generation of the fuel cell (10), the power generation of the fuel cell (10) can be limited based on the calculated power deviation.

[0102] Before the step of calculating the power deviation (S400), whether the rotational speed of the cooling pump (30) is greater than or equal to a preset rotational speed ( The method further includes a step (S310) of determining ≥ P, △P ≥ 0), and can limit the power generation of the fuel cell (10) based on the power deviation (△P) only when the rotational speed of the cooling pump (30) is greater than or equal to the preset rotational speed.

[0103] In the step (S600) of limiting the power generation of the fuel cell (10), the power generation of the fuel cell (10) is limited to a power generation limit value below a preset limit value according to the temperature of the fuel cell (10) or the temperature of the cooling medium, and when the actual power consumption of the cooling pump (30) is below the preset power consumption value (S500), a second offset set based on the power deviation can be applied to the temperature of the fuel cell (10) or the temperature of the cooling medium or to the power generation limit value.

[0104] After the step of calculating the power deviation (S400), if the actual power consumption of the cooling pump (30) is greater than the preset power consumption (S500), the method may further include a step (S700) of increasing the cooling amount of the cooling pump (30) based on the power deviation.

[0106] Although specific embodiments of the present invention have been illustrated and described, it will be obvious to those skilled in the art that the present invention can be modified and changed in various ways without departing from the technical spirit of the invention as provided by the following claims. Explanation of the symbols

[0108] 10 : Fuel cell 20 : Cooling line 30 : Cooling pump 40 : Cooling controller 50 : Generator controller

Claims

Claim 1 A fuel cell that generates electricity through the reaction of fuel gas and oxidizing gas; a cooling line connected to the fuel cell such that a cooling medium flows inside and the flowing cooling medium exchanges heat with the fuel cell; a cooling pump provided in the cooling line and circulating the cooling medium inside the cooling line when operated; a cooling controller that controls the operation of the cooling pump based on the temperature of the fuel cell or the temperature of the cooling medium; and a power generation controller that limits the power generation of the fuel cell based on the operation state of the cooling pump; wherein the power generation controller limits the power generation of the fuel cell based on at least one of a speed deviation, which is the difference between the rotational speed command of the cooling pump and the actual rotational speed, and a power deviation, which is the difference between the power consumption preset according to the rotational speed of the cooling pump and the actual power consumption of the cooling pump. Claim 2 A fuel cell overheating prevention control system according to claim 1, wherein the cooling line is equipped with a radiator that exchanges heat between an internal cooling medium and the outside, the cooling line is extended so that the inlet and outlet of the fuel cell circulate with the radiator, and the cooling pump is characterized by flowing part or all of the cooling medium discharged through the outlet of the fuel cell to the radiator, or flowing the cooling medium discharged from the radiator to the inlet of the fuel cell. Claim 3 A fuel cell overheating prevention control system according to claim 1, further comprising a temperature sensor located on the outlet side of the fuel cell in the cooling line and sensing the temperature of a cooling medium flowing inside; and a cooling controller controlling the operation of a cooling pump based on the temperature of the cooling medium sensed by the temperature sensor. Claim 4 A fuel cell overheating prevention control system according to claim 1, wherein the cooling controller controls the cooling pump to follow a rotational speed command set based on the temperature of the fuel cell or the temperature of the cooling medium. Claim 5 A fuel cell overheating prevention control system according to claim 1, wherein the power generation controller limits the power generation of the fuel cell to below a preset power generation limit based on the temperature of the fuel cell or the temperature of the cooling medium, and applies a first offset set based on speed deviation to the temperature of the fuel cell or the temperature of the cooling medium, or to the power generation limit. Claim 6 A fuel cell overheating prevention control system according to claim 5, wherein the power generation controller is configured to gradually reduce the temperature of the fuel cell or cooling medium that limits the power generation of the fuel cell as the magnitude of the speed deviation increases when the speed deviation is greater than or equal to a preset speed deviation value, or to gradually reduce the power generation limit value. Claim 7 delete Claim 8 A fuel cell overheating prevention control system according to claim 1, wherein the power generation controller limits the power generation of the fuel cell based on the power deviation only when the rotational speed of the cooling pump is greater than or equal to a preset rotational speed. Claim 9 A fuel cell overheating prevention control system according to claim 1, wherein the power generation controller limits the power generation of the fuel cell to below a preset power generation limit based on the temperature of the fuel cell or the temperature of the cooling medium, and when the actual power consumption of the cooling pump is below the preset power consumption, applies a second offset set based on the power deviation to the temperature of the fuel cell or the temperature of the cooling medium or to the power generation limit. Claim 10 A fuel cell overheating prevention control system according to claim 9, wherein the power generation controller is configured to gradually reduce the temperature of the fuel cell or cooling medium that limits the power generation of the fuel cell as the magnitude of the power deviation increases when the power deviation is greater than or equal to a preset power deviation value, or to gradually reduce the power generation limit value. Claim 11 A fuel cell overheating prevention control system according to claim 1, wherein the cooling controller increases the amount of cooling for cooling the cooling pump based on the power deviation when the actual power consumption of the cooling pump is greater than the preset power consumption. Claim 12 A method for preventing overheating of a fuel cell, comprising: a step of estimating the temperature of a fuel cell or sensing the temperature of a cooling medium; a step of controlling the operation of a cooling pump that circulates a cooling medium flowing into a cooling line connected to the fuel cell based on the estimated temperature of the fuel cell or the sensed temperature of the cooling medium; and a step of limiting the power generation of the fuel cell based on the operation state of the cooling pump; wherein, in the step of limiting the power generation of the fuel cell, the power generation of the fuel cell is limited based on at least one of a speed deviation, which is the difference between the rotational speed command of the cooling pump and the actual rotational speed, and a power deviation, which is the difference between the power consumption preset according to the rotational speed of the cooling pump and the actual power consumption. Claim 13 A method for preventing overheating of a fuel cell according to claim 12, wherein the step of controlling the operation of a cooling pump controls the cooling pump to follow a rotational speed command set based on the temperature of the fuel cell or the temperature of the cooling medium, and further comprises the step of calculating a speed deviation prior to the step of limiting the power generation of the fuel cell. Claim 14 A method for preventing overheating of a fuel cell according to claim 12, wherein in the step of limiting the power generation of the fuel cell, the power generation of the fuel cell is limited to a power generation limit value or lower according to the temperature of the fuel cell or the temperature of the cooling medium, and a first offset set based on the speed deviation is applied to the temperature of the fuel cell or the temperature of the cooling medium or to the power generation limit value. Claim 15 A method for preventing overheating of a fuel cell according to claim 12, further comprising a step of calculating a power deviation prior to a step of limiting the power generation of the fuel cell. Claim 16 A method for preventing overheating of a fuel cell according to claim 15, wherein in the step of limiting the power generation of the fuel cell, the power generation of the fuel cell is limited to a power generation limit value or lower according to the temperature of the fuel cell or the temperature of the cooling medium, and when the actual power consumption of the cooling pump is lower than or equal to the power consumption value, a second offset set based on the power deviation is applied to the temperature of the fuel cell or the temperature of the cooling medium or to the power generation limit value. Claim 17 A fuel cell overheating prevention control method according to claim 15, further comprising the step of, after the step of calculating the power deviation, increasing the amount of cooling for cooling the cooling pump based on the power deviation when the actual power consumed by the cooling pump is greater than the preset power consumed.

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