Method for controlling the opening of an air flow control valve in a fuel cell stack and device therefor

Abstract

A method performed by an apparatus of a fuel cell system, the method comprising: based on a fuel cell stack of the fuel cell system entering an idle operating state after start-up of the fuel cell system, controlling a gas flow to the fuel cell stack to cause a current of the fuel cell stack to converge to a predetermined current; based on the current of the fuel cell stack converging to the predetermined current, controlling a fuel cell direct current (DC-DC) converter (FDC) voltage drop slope; and based on the controlled FDC voltage drop slope of the FDC, controlling operation of the fuel cell stack.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0175655, filed with the Korean Intellectual Property Office on November 29, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a fuel cell system, and more specifically, to a technique for controlling the opening of an air flow control valve based on the degradation of the fuel cell stack in a fuel cell system entering an idle operating state. background

[0004] The descriptions in this background section are intended only to enhance understanding of the background of this disclosure and should not be construed as an admission that they correspond to prior art known to those skilled in the art.

[0005] Carbon neutrality is a hot topic globally. Major economies are exploring ways to expand electricity production by replacing fossil fuels with renewable energy.

[0006] Green energy systems refer to systems that convert energy obtained through renewable energy sources such as wind, hydro, tidal, and solar power into electricity and hydrogen.

[0007] Among them, green hydrogen is considered the ultimate environmentally friendly energy source because it does not emit any greenhouse gases from the production stage. Hydrogen, which is emerging as an alternative energy source globally, is roughly divided into gray hydrogen, blue hydrogen, and green hydrogen based on its production method.

[0008] Research on electric vehicles equipped with environmentally friendly hydrogen fuel cells is underway.

[0009] Compared to conventional electric vehicles based on high-voltage batteries, hydrogen fuel cell electric vehicles, due to their high energy density, can achieve fast charging and long driving range with a single hydrogen refueling.

[0010] In a vehicle fuel cell system, under normal operating conditions, hydrogen as fuel and air as oxidant are continuously supplied to the fuel cell stack. The current generated by the electrochemical reaction in the stack is extracted to charge the battery or power the inverter, thereby driving the vehicle's electric motor. The hydrogen and air supplied to the fuel cell stack continuously circulate between the negative electrode (fuel electrode) and the positive electrode (air electrode).

[0011] On the other hand, during idle operation, no current is extracted, and the supply of hydrogen and air is only used to maintain the pressure differential. Therefore, hydrogen and air are difficult to circulate between the negative and positive electrodes. This can increase gas permeation between the negative and positive electrodes and may easily lead to side reactions.

[0012] When the battery voltage is 0.8V or more in the idle operating state of the battery stack, an oxide film may form, thereby reducing the electrochemical surface area and causing battery stack degradation.

[0013] Furthermore, during idle operation, oxygen transferred from the positive electrode to the negative electrode may trigger the following side reaction on the electrode surface, thereby generating hydrogen peroxide (OH-). - Hydrogen peroxide may generate oxygen free radicals, leading to the decomposition of the polymer electrolyte membrane, which may degrade the battery's physical performance. To reduce gas cross-contamination, the air supply to the positive electrode can be cut off by turning off the air compressor or by allowing air to flow through an air flow control valve. However, this method may reduce the durability of individual products, and natural voltage depletion may take more than 20 seconds.

[0014] Therefore, a new method is being considered to avoid high-potential exposure and effectively reduce gas cross-contamination during idle operation. Summary of the Invention

[0015] This disclosure aims to address the aforementioned issues.

[0016] According to this disclosure, a method performed by an apparatus of a fuel cell system is provided, the method comprising: controlling the airflow to the fuel cell stack based on the fuel cell stack entering an idle operating state after the fuel cell system is started, such that the current of the fuel cell stack converges to a predetermined current; controlling the voltage drop slope of the fuel cell DC-DC converter (FDC) based on the current of the fuel cell stack converging to the predetermined current; and controlling the operation of the fuel cell stack based on the controlled voltage drop slope of the FDC.

[0017] The method may further include: performing feedback-based control on the air flow control valve of the fuel cell system based on the voltage of the fuel cell stack; and increasing the valve opening value of the air flow control valve based on the degradation value of the fuel cell stack, wherein the degradation value of the fuel cell stack is determined based on the number of times the feedback-based control is performed during the idle operation state of the fuel cell stack.

[0018] In this method, the air flow control valve may include: an air shut-off valve (ACV), which is a valve configured to block the air supply to the fuel cell stack, and an air pressure control valve (APC), which is a valve configured to control the air pressure.

[0019] In this method, performing feedback-based control may include: acquiring the current output voltage value of the fuel cell stack; acquiring the target output voltage value of the fuel cell stack associated with the current output voltage value; and identifying the voltage deviation between the target output voltage value and the current output voltage value, wherein the feedback-based control is performed based on the voltage deviation being greater than a predetermined reference deviation.

[0020] In this method, the target output voltage value is determined based on the falling slope of the FDC voltage, and the falling slope of the FDC voltage is applied during the period when the fuel cell stack enters an idle operating state.

[0021] In this method, the rate of decrease of the FDC voltage can be determined based on the output voltage value of the fuel cell stack after entering the idle operating state, the target output voltage value, and the predetermined waiting time to reach the target output voltage value.

[0022] In this method, performing feedback-based control may further include: determining a valve opening increase value required to make the current output voltage value of the fuel cell stack follow the decreasing slope of the FDC voltage based on the voltage deviation being greater than a predetermined reference deviation; and controlling the air flow control valve based on the determined valve opening increase value.

[0023] In this method, increasing the valve opening value may include: counting the number of times the fuel cell stack enters an idle operating state after the fuel cell system is started; counting the number of times feedback-based control is executed during the idle operating state of the fuel cell stack; calculating the ratio of the number of times feedback-based control is executed to the number of times the idle operating state is entered; and determining a valve opening increase value based on the ratio, wherein the ratio is calculated based on the fact that the number of times the idle operating state is entered after startup is greater than a predetermined reference value.

[0024] The method may further include: determining that the output voltage value of the fuel cell stack is within a voltage range defined by the falling slope of the FDC voltage based on a voltage deviation less than or equal to a predetermined reference deviation, and controlling the air flow control valve to maintain the current opening.

[0025] The method may also include: initializing the valve opening value of the air flow control valve when the fuel cell system restarts.

[0026] According to this disclosure, an apparatus for a fuel cell system is provided, the apparatus including: a processor; and a memory storing at least one instruction, which, when executed by the processor communicating with the memory, is configured to cause the apparatus to: control the airflow to the fuel cell stack based on the fuel cell stack of the fuel cell system entering an idle operating state after the fuel cell system is started, so as to cause the current of the fuel cell stack to converge to a predetermined current; and control the voltage drop slope of the fuel cell DC-DC converter (FDC) based on the current of the fuel cell stack converging to the predetermined current.

[0027] In this device, when a processor communicating with the memory executes at least one instruction, the instruction is configured to cause the device to: perform feedback-based control on the air flow control valve of the fuel cell system based on the voltage of the fuel cell stack; and increase the valve opening value of the air flow control valve based on a degradation value of the fuel cell stack, wherein the degradation value of the fuel cell stack is determined based on the number of times feedback-based control is performed during the idle operation of the fuel cell stack.

[0028] In this device, the air flow control valve may include: an air shut-off valve (ACV), which is a valve configured to block the air supply to the fuel cell stack, and an air pressure control valve (APC), which is a valve configured to control the air pressure.

[0029] In this device, when a processor communicating with a memory executes at least one instruction, the instruction is configured to cause the device to perform feedback-based control in the following manner: acquiring the current output voltage value of the fuel cell stack; acquiring a target output voltage value of the fuel cell stack associated with the current output voltage value; and identifying the voltage deviation between the target output voltage value and the current output voltage value, and performing feedback-based control based on the voltage deviation being greater than a predetermined reference deviation.

[0030] In this device, the target output voltage value is determined based on the falling slope of the FDC voltage, and the falling slope of the FDC voltage is applied during the idle operation of the fuel cell stack.

[0031] In this device, the rate of decrease of the FDC voltage is determined based on the output voltage value of the fuel cell stack after entering the idle operating state, the target output voltage value, and the predetermined waiting time to reach the target output voltage value.

[0032] According to this disclosure, a method performed by an apparatus of a fuel cell system is provided, the method comprising: reducing the air supply to the fuel cell stack to reduce the current of the fuel cell stack based on detecting that the fuel cell stack of the fuel cell system has entered an idle operating state; controlling the voltage of the fuel cell stack to follow a predetermined voltage drop curve during the idle operating state based on the current of the fuel cell stack decreasing to a predetermined threshold; adjusting the air supply conditions based on the deviation between the fuel cell stack voltage and a reference voltage; and controlling the operation of the fuel cell system based on the adjusted air supply conditions.

[0033] In this method, adjusting the air supply conditions may include adjusting the opening of the air flow control valve of the fuel cell system based on the deviation.

[0034] The method may also include updating control parameters of the air supply conditions based on the adjustment frequency of the fuel cell stack during multiple idle operating states.

[0035] In this method, a predetermined voltage drop curve is defined based on the difference between the initial voltage of the fuel cell stack and the target output voltage value, as well as based on the duration of reaching the target output voltage value. Attached Figure Description

[0036] The above and other objects, features and advantages of this disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings:

[0037] Figure 1 Examples of fuel cell systems according to embodiments of the present disclosure are shown;

[0038] Figure 2 An example of the overall configuration of a vehicle fuel cell system according to an embodiment of the present disclosure is shown;

[0039] Figure 3 An example is shown of a fuel cell system according to an embodiment of the present disclosure and an example of controlling the opening of an air flow control valve based on the voltage drop slope of a fuel cell DC-DC converter (FDC).

[0040] Figure 4 Examples of electrochemical reactions in a fuel cell stack according to this disclosure are shown;

[0041] Figure 5 Show Figure 3 Examples of detailed configurations for a fuel cell controller (FCC);

[0042] Figure 6 An example is shown of a method for controlling the opening of an air flow control valve in a fuel cell stack according to an embodiment of the present disclosure;

[0043] Figure 7An example is shown of a method for controlling the opening of an air flow control valve based on the falling slope of the FDC voltage in a fuel cell system according to an embodiment of the present disclosure;

[0044] Figure 8 An example is shown of a method for controlling the opening of an air flow control valve based on the voltage drop slope of the FDC in a fuel cell system according to another embodiment of the present disclosure;

[0045] Figure 9 An example is shown of controlling the opening of an air flow control valve based on the falling slope of the FDC voltage in a fuel cell system according to embodiments of the present disclosure; and

[0046] Figure 10 An example of a computing device according to an embodiment of the present disclosure is shown. Detailed Implementation

[0047] Some embodiments of this disclosure will be described in detail below with reference to the exemplary accompanying drawings. When adding reference numerals to the components in the various drawings, it should be noted that identical or equivalent components are represented by the same numerals, even if they are shown in other drawings. Furthermore, in the description of embodiments of this disclosure, detailed descriptions will be omitted when it is determined that a detailed description of a related known configuration or function would interfere with the understanding of the embodiments of this disclosure.

[0048] In describing components according to embodiments of this disclosure, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are intended only to distinguish one component from others and do not limit the nature, order, or sequence of the components. Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that terms, such as those defined in common dictionaries, shall be interpreted as having a meaning consistent with their meaning in the relevant technical context and shall not be construed as having an idealized or overly formal meaning unless expressly defined herein.

[0049] For the purposes of this application and claims, the exemplary phrase “at least one of the following: A, B, or C” or “at least one of A, B, or C” is used, which means “at least one A, or at least one B, or at least one C, or any combination of at least one A, at least one B, and at least one C.” Furthermore, exemplary phrases used herein, such as “A, B, or C,” “at least one of A, B, and C,” “at least one of A, B, or C,” etc., may refer to each listed item or all possible combinations of listed items. For example, “at least one of A or B” may mean (1) at least one A; (2) at least one B; or (3) at least one A and at least one B.

[0050] As used in this specification, the terms "module" or "unit" refer to software and / or hardware components, and a "module" or "unit" performs certain operations / functions / roles. However, a "module" or "unit" should not be construed as being limited to software or hardware. A "module" or "unit" may be configured to reside in addressable storage media or be executed by one or more processors.

[0051] Therefore, for example, a "module" or "unit" can include at least one of the following: a component (e.g., a software component, an object-oriented software component, a class component, and a task component), a process, a function, a property, a procedure, a subroutine, a program code segment, a driver, firmware, microcode, a circuit, data, a database, a data structure, a table, an array, or a variable. The functionality provided in a component, "module," or "unit" can be combined into a smaller number of components, "modules," or "units," or further divided into other components, "modules," or "units."

[0052] In this disclosure, "module" or "unit" can be considered as processor and memory. "Processor" should be broadly understood to include general-purpose processors, central processing units (CPUs), microprocessors, digital signal processors (DSPs), microcontrollers, state machines, etc. In some contexts, "processor" can refer to application-specific integrated circuits (ASICs), programmable logic devices (PLDs), or field-programmable gate arrays (FPGAs). For example, "processor" can refer to a combination of processing devices (e.g., a combination of a DSP and a microprocessor), a combination of multiple microprocessors, a combination of one or more microprocessors with a DSP core, or any other such combination. Furthermore, "memory" should be broadly understood to include any electronic component capable of storing electronic information. "Memory" can refer to various types of processor-readable media, such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, magnetic or optical data storage devices, and registers. Memory can be in electronic communication with the processor when the processor can read information from the memory and / or record information in the memory. The memory integrated into the processor is in electronic communication with the processor.

[0053] One or more features described herein can be provided as a computer program stored in a computer-readable recording medium for execution on a computer. This medium can continuously store a computer-executable program or temporarily store the program for execution or download. Furthermore, the medium can be a variety of recording or storage devices in the form of a single hardware device or a combination of multiple hardware devices, and is not limited to media directly connected to a computer system, but can also be distributed across a network. Examples of such media include magnetic media (e.g., hard disks, floppy disks, or magnetic tapes), optical recording media (e.g., CD-ROMs or DVDs), magneto-optical media (e.g., optical discs), and ROM, RAM, or flash memory, in which they are configured to store program instructions. Other examples of such media include media or storage media managed by application stores that distribute applications or by various other sites or servers that provide or distribute software.

[0054] In a hardware implementation, the processing unit for performing these technologies may be implemented as one or more of the following: ASIC, DSP, digital signal processing device, programmable logic device, field-programmable gate array, processor, controller, microcontroller, microprocessor, electronic device, or computer, or a combination thereof, which are intended to perform the functions described in this disclosure.

[0055] The following will refer to Figures 1 to 10 The embodiments of this disclosure are described in detail.

[0056] Figure 1 An example of a fuel cell system according to an embodiment of the present disclosure is shown.

[0057] like Figure 1 As shown, in the fuel cell system 100 according to an embodiment of the present disclosure, oxygen (air) and hydrogen, which serve as fuel for the fuel cell stack 110, are supplied to the positive electrode 111 and negative electrode 112 of the membrane electrode assembly, respectively, through flow channels of the separator (e.g., serpentine channels, parallel flow fields, or staggered paths). For example, oxygen (air) is supplied to the positive electrode 111 in the fuel cell stack 110, and hydrogen is supplied to the negative electrode 112 in the fuel cell stack 110 (e.g., via flow channels, distribution manifolds, or air inlets).

[0058] In addition, the coolant 113 stored in the refrigeration storage (not shown) can be supplied to the fuel cell stack 110 through cooling lines (e.g., closed-loop cooling circuit, thermal management line or heat exchange pipe, etc.).

[0059] First, the following can be configured on the positive electrode 111: an air humidifier (hereinafter referred to as "AHF") 130 for maintaining the humidity of oxygen (air) which is crucial to the reaction of the fuel cell stack 110; and valves for controlling the oxygen (air) supply (e.g., an air shut-off valve (hereinafter referred to as "ACV") 140 and a pressure control valve (or operating pressure control valve) (hereinafter referred to as "APC") 120, etc.).

[0060] Here, AHF 130 supplies moisture from the oxygen (air) inlet side. The oxygen (air) supplied along with the moisture moves along the flow path in the fuel cell stack 110 and reacts with hydrogen (e.g., generating electricity, water, and heat), thus producing water. Here, the water produced by the electrochemical reaction interferes with the flow of oxygen and hydrogen, so it needs to be removed from the fuel cell stack 110 (e.g., through a drainage system, a cleaning operation, or a water trap).

[0061] Therefore, at least one of the following can be configured on the negative electrode 112: a fuel line cleaning valve (hereinafter referred to as "FPV") 180, a fuel line water trap (hereinafter referred to as "FWT") 160, a fuel line level sensor (hereinafter referred to as "FL") 150, and a fuel line drain valve (hereinafter referred to as "FDV") 170, for discharging impurities and condensates (e.g., water, nitrogen, or residual hydrogen) from the fuel cell stack 110. Specifically, the FPV 180 discharges impurities (e.g., nitrogen, inert gases, or contaminants) generated at the negative electrode 112 in the fuel cell stack 110, the FWT 160 collects condensates generated at the negative electrode 112 in the fuel cell stack 110 until a certain level is reached, and then the collected condensates are discharged to the positive electrode 111 via the FDV 170 (e.g., using a pressure-driven flow, a purge pulse, or a timed drainage program).

[0062] To improve the efficiency of the fuel cell stack 110, the APC 120 is used to control the angle of the valve disc during operation to regulate the pressure in the flow path of the air supply system (or oxidation gas supply system, such as the positive electrode air path, air circuit, or oxidant manifold).

[0063] Figure 2 An example of the overall configuration of a vehicle fuel cell system according to an embodiment of the present disclosure is shown.

[0064] The vehicle fuel cell system 200 can be used as an on-board power system installed on a fuel cell vehicle and may include: a fuel cell stack 20 that generates electricity by receiving reaction gases (e.g., fuel gas, oxidizing gas, ambient air, or reformed fuel gas); an oxidizing gas supply system 30 for supplying air to the fuel cell stack 20 as an oxidizing gas; a fuel gas supply system 40 for supplying hydrogen to the fuel cell stack 20 as a fuel gas; a power meter 50 for controlling the charging or discharging of the power source; a cooling system 60 for cooling the fuel cell stack 20; and a controller (ECU) 70 that controls the entire system (e.g., operating modes, valve actuation, or system diagnostics).

[0065] The fuel cell stack 20 can be a solid polymer electrolyte type fuel cell stack formed by laminating multiple cells in series (e.g., an MEA stacked with bipolar plates, end plates, and connecting rods). An oxidation reaction occurs at the negative electrode 112 of the fuel cell stack 20, and a reduction reaction occurs at the positive electrode 111.

[0066] The following can be installed in the fuel cell stack 20: a voltage sensor 71 for detecting the output voltage of the fuel cell stack 20; a current sensor 72 for detecting the generated current; and a battery voltage sensor 73 for detecting the battery voltage (e.g., integrated into the battery stack frame, located at a critical monitoring channel, or embedded in the battery stack interconnect structure).

[0067] The oxidizing gas supply system 30 may include: an oxidizing gas passage 34 through which oxidizing gas is supplied to the positive electrode 111 of the fuel cell stack 20; and an oxidizing exhaust gas passage 36 through which oxidizing exhaust gas (e.g., residual air, moisture, or inert byproducts) discharged from the fuel cell stack 20 flows out. The oxidizing gas passage 34 may be equipped with: an air compressor 32 that introduces and compresses the oxidizing gas from the atmosphere through a filter 31; a humidifier 33 for humidifying the oxidizing gas supplied to the positive electrode 111 of the fuel cell stack 20; and a throttle valve 35 for regulating the supply amount of oxidizing gas (e.g., to manage stoichiometric flow rate or oxygen excess ratio). The oxidizing exhaust gas passage 36 may be equipped with: a post-pressure regulating valve 37 for regulating the oxidizing gas supply pressure; and a humidifier 33 for exchanging moisture between the oxidizing gas (dry gas) and the oxidizing exhaust gas (humid gas) (e.g., for humidity recovery, thermal regulation, or pressure balancing).

[0068] The fuel gas supply system 40 may include: a fuel gas supply source 41; a fuel gas passage 45 through which fuel gas from the fuel gas supply source 41 is supplied to the negative electrode 112 of the fuel cell stack 20; a circulation passage 46 for returning fuel exhaust gas discharged from the fuel cell stack 20 to the fuel gas passage 45; a circulation pump 47 for pumping fuel exhaust gas inside the circulation passage 46 back to the fuel gas passage 45; and an exhaust drainage passage 48, which branches off and connects to the circulation passage 46 (e.g., for removing accumulated water, nitrogen, or contaminants).

[0069] For example, the fuel gas supply source 41 can be formed as a high-pressure hydrogen tank or made of a hydrogen storage alloy, and can store high-pressure hydrogen (e.g., 35 MPa to 70 MPa, or higher depending on the vehicle platform). When the shut-off valve 42 is open, fuel gas flows from the fuel gas supply source 41 into the fuel gas passage 45 (e.g., flowing under tank pressure through a high-pressure line or regulated flow path, etc.). The fuel gas can be depressurized to, for example, about 200 kPa by the regulator 43 or the injector 44 and supplied to the fuel cell stack 20.

[0070] In addition, the fuel gas supply source 41 may include a reformer that produces hydrogen-rich reformed gas from hydrocarbon-based fuels (e.g., natural gas, methanol, or gasoline), and a high-pressure tank that compresses the reformed gas produced in the reformer to a high-pressure state.

[0071] The regulator 43 can be a device for adjusting the inlet pressure (primary pressure) to a preset secondary pressure (e.g., suitable for fuel cell stack inlet conditions, such as 110 kPa-250 kPa, etc.), and can include, for example, a mechanical pressure reducing valve for reducing the primary pressure. This mechanical pressure reducing valve can have a housing containing a back pressure chamber and a pressure control chamber, separated by a partition (e.g., made of an elastomer, fluoropolymer, or reinforced membrane material, etc.), and can reduce the primary pressure to a predetermined pressure in the pressure control chamber by the back pressure inside the back pressure chamber, thereby enabling a secondary pressure (e.g., suitable for fuel cell stack input, such as 110 kPa to 250 kPa, etc.).

[0072] The injector 44 can be an electronically driven valve for opening or closing. It directly drives the valve body using electronic driving force (e.g., via a solenoid, motor actuator, or piezoelectric element) at predetermined driving cycles, separating the valve body from the valve seat, thereby regulating the flow rate or pressure of the gas. The injector 44 may include: a valve seat with an injection port through which gaseous fuel (e.g., hydrogen, reformed gas, or synthesis gas) is injected; a nozzle body that supplies and guides the gaseous fuel to the injection port (e.g., via a tapered pipe, vortex channel, or orifice inlet); and a valve body that conforms to and remains movable in an axial direction (gas flow direction) relative to the nozzle body, and opens or closes the injection port (e.g., via solenoid actuation, stepper motor control, or piezoelectric drive).

[0073] The exhaust drain valve 49 can be located in the exhaust drain passage 48 (e.g., near the low-point reservoir, connecting manifold, or condensate collection area). The exhaust drain valve 49 can be operated according to instructions from the controller 70 to discharge fuel exhaust gas and moisture containing impurities from the circulation passage 46 to the outside (e.g., during purging cycles, shutdown procedures, or condensate management phases). By opening (e.g., using the opening valve of the exhaust drain valve 49) the exhaust drain valve 49, the impurity concentration of the fuel exhaust gas in the circulation passage 46 can be reduced, and the hydrogen concentration of the fuel exhaust gas circulating in the circulation system can be increased, thereby improving fuel utilization, stack efficiency, and reaction uniformity.

[0074] Fuel exhaust gas discharged through exhaust drain valve 49 mixes with oxidizing exhaust gas flowing through oxidizing exhaust gas passage 36 and is diluted by a diluter (not shown) (e.g., to meet exhaust safety standards, reduce combustibility, or stabilize exhaust composition). Circulation pump 47 can circulate the fuel exhaust gas in the circulation system and supply it to fuel cell stack 20 via a drive motor (e.g., a motor with speed controlled based on flow demand, stack load, or purging time).

[0075] The power meter 50 may include a fuel cell DC-DC converter (hereinafter referred to as "FDC") 51a, a bidirectional high-voltage DC-DC converter (hereinafter referred to as "BHDC") 51b, a high-voltage battery 52, a traction inverter 53, a traction motor 54, and auxiliary equipment 55.

[0076] FDC 51a can be a bidirectional voltage converter responsible for controlling the output voltage of fuel cell stack 20. It can convert (increase or decrease) the output voltage input to the primary side (e.g., input side: fuel cell stack 20) ​​to a voltage different from the primary side, outputting the converted voltage to the secondary side (e.g., output side: inverter 53). Conversely, it can convert the voltage input to the secondary side to a voltage different from the secondary side, outputting the converted voltage to the primary side (e.g., to support load transients, regenerative braking, or battery buffering). The operating points I and V of fuel cell stack 20 can be controlled by the voltage conversion control of FDC 51a (e.g., for maintaining power quality, stack efficiency, or battery integration).

[0077] BHDC 51b can be used to control the input voltage of inverter 53 and can have a circuit configuration that is the same as or similar to that of FDC 51a, but this disclosure is not limited thereto. The circuit configuration of BHDC 51b can adopt any configuration capable of controlling the input voltage of inverter 53 (e.g., by buck, boost, or full-bridge topology, etc.). BHDC 51b can convert the power generated by fuel cell stack 20 to charge high-voltage battery 52, or convert the power charged in high-voltage battery 52 to supply the converted power to traction inverter 53 and auxiliary equipment 55 (e.g., HVAC system, pump, sensor, or ECU, etc.).

[0078] The high-voltage battery 52 can be used as a source of residual power storage, a source of regenerative energy storage during regenerative braking, and an energy buffer when the load changes according to the acceleration or deceleration of the fuel cell vehicle (e.g., during rapid throttle input, gear shifting, or downhill coasting). For example, secondary batteries such as nickel-cadmium batteries, nickel-metal hydride batteries, and lithium secondary batteries (e.g., lithium-ion, lithium polymer, or lithium iron phosphate batteries) can be suitable as high-voltage batteries 52.

[0079] The traction inverter 53 can be, for example, a pulse width modulation (PWM) inverter driven by a pulse width modulation method, and can convert the DC voltage output from the fuel cell stack 20 or the high-voltage battery 52 into a three-phase alternating current (AC) voltage according to control commands from the controller 70, thereby controlling the rotational torque of the traction motor 54. The traction motor 54 is a motor (e.g., a three-phase AC motor, a permanent magnet synchronous motor, or a switched reluctance motor, etc.) used to drive the wheels 56L and 56R, and can constitute the power source of the fuel cell vehicle (e.g., providing propulsion torque under various load and terrain conditions, etc.).

[0080] Auxiliary equipment 55 refers to motors (e.g., power sources such as pumps, fan motors, or blower motors) installed in various parts of the fuel cell system 100, inverters used to drive these motors, and various on-board auxiliary equipment (e.g., air compressors, injectors, cooling circulation pumps, radiators, cabin HVAC blowers, or exhaust system components, etc.).

[0081] The cooling system 60 may include cooling channels 61, 62, 63, and 64 for the refrigerant circulating inside the fuel cell stack 20 to flow through; a circulation pump 65 for pumping the refrigerant; a radiator 66 for heat exchange between the refrigerant and outside air; a three-way valve 67 for switching the refrigerant circulation path; and a temperature sensor 74 for detecting the temperature of the fuel cell stack 20 (e.g., to maintain thermal balance, prevent overheating, or optimize electrochemical efficiency). During normal operation after the hot air cycle is complete, the opening or closing of the three-way valve 67 can be controlled so that the refrigerant flowing out of the fuel cell stack 20 flows through cooling channels 61 and 64, is cooled by the radiator 66, and then flows back to the fuel cell stack 20 (e.g., to maintain the optimal stack operating temperature, such as 60-80°C). During the hot air operation immediately after system startup, the opening or closing of the three-way valve 67 can be controlled so that the refrigerant flowing out of the fuel cell stack 20 flows through the cooling channels 61, 62 and 63 and then flows back to the fuel cell stack 20 (e.g., through the radiator to accelerate preheating).

[0082] The controller 70 is a computer system equipped with a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and input / output interfaces. It is used as a control device to control various parts of the fuel cell system 100 (e.g., oxidant gas supply system 30, fuel gas supply system 40, power meter 50, and cooling system 60). For example, when the controller 70 receives a start signal IG output from the ignition switch, the controller 70 can start running the fuel cell system 100 and calculate the power required by the entire system based on the throttle opening signal ACC output from the throttle sensor, the vehicle speed signal VC output from the vehicle speed sensor, etc. (e.g., throttle demand, regenerative braking mode, or vehicle climbing angle).

[0083] The total power required by the entire system is the sum of the power required to drive the vehicle and the auxiliary power. The auxiliary power may include the power consumed by onboard auxiliary equipment (e.g., humidifiers, air compressors, hydrogen pumps, or cooling circulation pumps), the power consumed by equipment required to drive the vehicle (e.g., transmissions, wheel control devices, steering systems, or suspension systems), and the power consumed by equipment located in the passenger cabin (e.g., air conditioning, lighting, or audio systems, for example, to support passenger comfort and infotainment).

[0084] Furthermore, the controller 70 can control the oxidizing gas supply system 30 and the fuel gas supply system 40, thereby determining the distribution of output power between the fuel cell stack 20 and the high-voltage battery 52, calculating the power generation command value, and ensuring that the power generation of the fuel cell stack 20 meets the required power generation P. req (For example, based on driver demand, battery SOC, or energy efficiency optimization). Furthermore, the controller 70 can control the operating point of the fuel cell stack 20 by controlling the FDC 51a, etc. To obtain the target vehicle speed based on the throttle opening, the controller 70 can output, for example, AC voltage command values ​​for the U-phase, V-phase, and W-phase as switching commands for the traction inverter 53, and control the output torque and speed of the traction motor 54 (e.g., in response to slope, road load, or regenerative braking, etc.).

[0085] Figure 3 An example is shown of a fuel cell system according to an embodiment of the present disclosure and an example of controlling the opening of an air flow control valve based on the voltage drop slope of a fuel cell DC-DC converter (FDC).

[0086] refer to Figure 3 The fuel cell system 300 may include at least one of the following: fuel cell stack 310, hydrogen storage tank 320, hydrogen control valve (HCV) 330, air compressor (ACP) 340, pressure control valve (APC) 350, air shut-off valve (ACV) 360, voltage / current sensor 370, and fuel cell controller (FCC) 380 (e.g., implemented as an embedded control circuit or an integrated system-level controller).

[0087] The fuel cell stack 310 generates electricity via an electrochemical reaction fueled by hydrogen (H2) introduced from a hydrogen storage tank 320 and air introduced from outside the vehicle, wherein the air includes oxygen (O2). The generated electricity can be supplied to an inverter via an FDC (not shown), which converts the electricity to charge the vehicle battery (not shown) or drive an electric motor within the vehicle (not shown) (e.g., depending on load demand or energy management strategies, etc.).

[0088] The amount of hydrogen introduced into the fuel cell stack 310 as fuel can be controlled by HCV 330, and the amount of air as oxidant can be controlled by controlling at least one of ACP 340, APC 350 and ACV 360 (e.g., based on pressure sensors, flow targets or stack temperature, etc.).

[0089] FCC 380 can control at least one of HCV 330, ACP 340, APC 350 and ACV 360 to control the amount of hydrogen and oxygen supplied to fuel cell stack 310 (e.g., to maintain optimal stoichiometry, manage heat load or reduce parasitic losses, etc.).

[0090] The voltage / current sensor 370 may include a voltage sensor for detecting the output voltage of the fuel cell stack 310 and a current sensor for detecting the generated current (e.g., using a parallel resistor, a Hall effect sensor, or a battery stack integrated sensing circuit). Here, the output voltage can be detected on a per-channel basis and / or per-cell basis within a channel of the fuel cell stack 310, and the generated current can be detected on a per-channel basis and / or per-cell basis within a channel and / or per-segment basis within a cell (e.g., for purposes such as local performance diagnostics, degradation tracking, or balancing). The voltage / current sensor 370 can provide the current and voltage detection results to FCC 380. Here, a channel may include multiple cells, and a cell may include multiple segments.

[0091] When the fuel cell stack 110 is started and enters an idle operating state, the FCC 380 can request the voltage / current sensor 370 to measure the voltage and / or current through a predetermined control command (e.g., when the fuel cell stack is cooling, the vehicle is stopped, or in a neutral load state), thereby obtaining information on the voltage and / or current distribution inside the fuel cell stack 110.

[0092] According to this embodiment, the FCC 380 can perform the following control: at the start time of entering the idle operating state, the ACP 340 maintains a minimum or target speed (RPM) for a predetermined time, while the valves of the ACV 360 and APC 350 are almost closed, so only a minimum or target flow rate of air is supplied to the positive electrode 111 (e.g., to reduce parasitic load, suppress hydrogen crossflow, or stabilize the stack voltage, etc.). In this case, the current of the fuel cell stack 310 can be converged to a preset target current (e.g., minimum) or lower by the minimum flow rate of air supply. Here, the target current (e.g., minimum) is used to control to 0A, but considering factors such as sensor offset (e.g., to account for sensor drift or hardware thresholds, etc.), the target current can also be set to a constant value close to 0A. For example, the minimum current can be set to 0.2A, but is not limited to this. Here, the rotational speed of the ACP 340 and the valve opening values ​​of the APC 350 / ACV 360 for convergence to the minimum current can be determined and set through pre-testing (e.g., during system calibration, vehicle commissioning, or development testing) to ensure that the current converges to the minimum current within a predetermined time, i.e., the target (e.g., maximum) waiting time for target (e.g., within 10 to 20 seconds, depending on system thermal and fluid dynamics, etc.) convergence. For example, the maximum waiting time for minimum current convergence can be set to a maximum of 20 seconds or less, but this is merely an implementation method, and the maximum waiting time for minimum current convergence can be set differently depending on the design of those skilled in the art and the application and purpose of the fuel cell system (e.g., for buses, stationary backup systems, or commercial transportation applications, etc.).

[0093] If the current of the fuel cell stack 310 converges to a minimum current or lower through a minimum air supply, the FCC 380 can adaptively adjust the valve openings of the ACV 360 and APC 350 based on the voltage deviation between the target voltage and the actual stack voltage, according to a preset FDC voltage drop slope (e.g., -0.9V / s to simulate a controlled decay curve, etc.).

[0094] According to the FCC 380 disclosed herein, the current potential can be stably reduced to a final target potential through PID control based on the descent slope of the FDC voltage. This prevents droplet formation due to potential deviation and the resulting battery stack degradation (e.g., mitigating positive electrode overflow, membrane damage, or catalyst flushing). Here, the potential descent rate can be determined by a preset descent slope of the FDC voltage.

[0095] Here, PID control takes the form of a feedback controller. It is a method that measures the output value of the object to be controlled, compares the output value with a desired reference value or setpoint to calculate the error, and uses the error value to calculate and control the control value required for the control (e.g., adjusting the opening of an air valve to perform voltage slope tracking).

[0096] For example, the PID control according to this disclosure can be implemented as follows: a voltage deviation is calculated by comparing the current battery stack output voltage with a target battery stack voltage, wherein the target battery stack voltage is a reference value (e.g., derived from a predetermined voltage ramp curve, a mapped slope table, or a real-time optimization function, etc.), and if the voltage deviation exceeds a predetermined reference deviation, an upward adjustment of the air flow control valve opening is calculated and controlled based on the calculated voltage deviation or the calculated voltage drop slope (e.g., to maintain a stable voltage drop, suppress low potential deviation, or improve water management, etc.).

[0097] According to this embodiment, the descent slope of the FDC voltage can be set so that the current potential reaches the final target potential within a predetermined time (e.g., based on system preheating time, battery stack degradation level, or air supply delay, etc.). For example, if the time for the current potential to reach the final target potential after converging to the minimum current is 50 seconds, the battery stack voltage level after entering idle operation is 370V, and the final target voltage level is 324V, then the descent slope of the FDC voltage can be calculated as -0.92V / second ((370V-324V) / 50 seconds) (e.g., this can be stored as a slope parameter in the control logic and dynamically applied through voltage tracking algorithms, etc.).

[0098] When the battery stack output voltage decreases rapidly and forcibly instead of gradually decreasing along the FDC voltage drop slope, a large stack current is generated instantaneously, creating droplets within the stack (e.g., due to sudden electrochemical imbalance or water backflow diffusion). Especially during idle operation, where almost no airflow is supplied to the stack, the generated droplets may not be blown out (e.g., due to insufficient purge flow or lack of convection removal). Droplets accumulating in the stack can impede gas reactions (e.g., by blocking reactant inflow, disrupting catalyst activity, or causing localized overflow). Consequently, the stack voltage drops sharply, individual cell voltage deviations increase, and degradation due to low-potential exposure occurs (e.g., including catalyst overflow, membrane degradation, or localized stratification).

[0099] According to this embodiment, the FCC 380 can increase the valve openings of ACV 360 and APC 350 based on the ratio of the cumulative number of times PID control is executed in the idle operating state (i.e., cumulative PID control count) to the cumulative number of times the system enters the idle operating state after startup (i.e., cumulative idle operating state count). This can be achieved by using a learning correction factor or mapping offset adjustment to reflect battery stack aging trends or changes in air demand. For example, the FCC 380 can reduce the frequency of PID control and adaptively update and apply target (e.g., minimum) valve opening values ​​corresponding to ACV 360 and APC 350 by learning about battery stack degradation (e.g., caused by aging, membrane thinning, or catalyst deactivation), thereby improving the battery stack output voltage's ability to follow the rate of decline of the FDC voltage. This can also improve valve durability (e.g., by reducing unnecessary drive cycles or oscillating control). In one embodiment, the degree of battery stack degradation can be determined based on the PID control count. For example, the degree of degradation of the battery stack can be determined by the ratio of the cumulative number of times PID control is executed to the number of times it enters an idle operating state after startup (e.g., to quantify responsiveness loss or increased compensation requirements).

[0100] When the valve opening for maintaining the corresponding voltage is set based on the initial battery stack state, the electrochemical surface area may decrease as battery stack performance deteriorates, and catalyst shedding may occur. Due to degradation compared to the same airflow rate (e.g., compensation is needed by increasing airflow rate or changing the setpoint), it may be unable to maintain the required battery stack voltage. To address this issue, under normal operating conditions, the following method can be used: when the voltage decreases as the battery stack deteriorates at the target output, the target output can be obtained by increasing the current. Furthermore, in the high-power range, even small differences in the APC 350 opening can result in significant pressure deviations. In this case, pressure errors can be compensated by feedback control of the APC 350 based on the error between the actual sensor pressure and the target air pressure (e.g., using the pressure sensor signal or a mapping deviation threshold).

[0101] When entering the idle operating state, the fuel cell system 300 of this disclosure can prevent stack degradation due to droplet formation in advance by performing PID control that follows the falling slope of the FDC voltage and optimizing the minimum valve opening value in the idle operating state by learning the minimum valve opening (e.g., updating based on the PID activity frequency or voltage tracking deviation trend).

[0102] The detailed configuration and operation of the FCC 380 will become clearer with the accompanying drawings described later.

[0103] Figure 4Examples of electrochemical reactions in a fuel cell stack according to this disclosure are shown.

[0104] refer to Figure 4 The fuel cell stack 400 may generally include a fuel electrode as the negative electrode, an air electrode as the positive electrode, and an electrolyte membrane (e.g., a proton exchange membrane in a PEM fuel cell) disposed between the fuel electrode and the air electrode.

[0105] In the fuel cell stack of the fuel cell system 200, hydrogen injected into the fuel electrode and oxygen injected into the air electrode undergo an electrochemical reaction to continuously generate water, i.e., water (H2O) (for example, as a byproduct of redox reactions that occur during power generation).

[0106] The catalyst layer formed to enable chemical reactions in the fuel cell stack can be contained on both the front and back sides of the electrolyte membrane. For example, a catalyst layer can be formed using carbon powder coated with a platinum (Pt)-based catalyst, but this is merely one implementation; other catalyst materials (e.g., iridium, ruthenium, cobalt-based materials, or platinum alloys) can be used according to the design of those skilled in the art. The catalyst layer can be used to form a gas diffusion layer (e.g., to facilitate reactant transport and moisture removal while maintaining electronic conductivity, etc.).

[0107] Hydrogen and oxygen injected into the left and right sides of the fuel cell stack are ionized through oxidation and reduction processes (e.g., at the negative and positive electrodes, respectively, under controlled heat and humidity conditions, etc.).

[0108] When hydrogen (H2) is injected through the hydrogen inlet on the fuel electrode side, the hydrogen reacts with the catalyst and decomposes into hydrogen ions (H+). + ) and electrons (e - Here, the chemical reaction formula is 2H₂. - >4H + +4e - .

[0109] Hydrogen ions pass through the electrolyte membrane and move to the air electrode, while electrons generated at the fuel electrode pass through an external circuit and generate an electric current (which can be used to drive a motor or auxiliary system, for example). In this case, the generated current can be used to drive the motor of an electric vehicle. The current generated in the fuel cell stack can be used to charge the battery of an electric vehicle.

[0110] When oxygen (O2) is injected through the air inlet on one side of the air electrode, oxygen (O2) and electrons (4e) react... - Under the action of a catalyst, it reacts to produce oxygen ions (2O). 2- In this case, the generated oxygen ions (2O) 2- ) and hydrogen ions (4H -The water passes through the electrolyte membrane and reacts to produce water (2H2O). In this case, the water produced, along with the heat generated during the chemical reaction inside the battery, is discharged to the outside through the outlet on the other side of the air electrode (e.g., via an integrated water management or purging system).

[0111] Figure 5 Show Figure 3 An example of a detailed configuration of a fuel cell controller (FCC).

[0112] refer to Figure 5 FCC 380 may include at least one of the following: operating status monitoring device 510, battery stack current minimization device 520, voltage monitoring device 530, voltage drop slope calculation device 540, PID controller 550, minimum valve opening learning device 560, and storage device 570 (e.g., for storing calibration data, learned control parameters, or voltage curves).

[0113] The operating status monitoring device 510 can determine whether the fuel cell stack 310 has entered the idle operating state from the normal operating state based on predetermined conditions for entering the idle operating state (e.g., current consumption threshold, torque demand signal, or system state transition).

[0114] For example, a normal operating state and an idle operating state can be determined based on whether current is withdrawn from the fuel cell stack 310 (e.g., by monitoring load demand, inverter input, or vehicle traction power request, etc.). However, this is only one implementation. In another implementation, a normal operating state and an idle operating state can be determined based on at least one of the output voltage, power generation current, and gas supply quantity of the fuel cell stack 310 (e.g., inferred from flow sensors, pressure signals, or control flags, etc.).

[0115] When entering an idle operating state, the battery stack current minimization device 520 can perform control to make the battery stack current converge to a preset minimum current value within a predetermined time (e.g., to prepare for the voltage drop slope while suppressing cross decay, etc.).

[0116] For example, the battery stack current minimization device 520 can perform the following control:

[0117] At the initial point of entry into idle operation, ACP 340 maintains a minimum rotational speed (RPM) for a predetermined time, while the valve discs of ACV 360 and APC 350 are almost closed, for example, controlled at 5 degrees or less (e.g., controlled at 1 to 3 degrees depending on the system design), thereby supplying only a minimum flow of air to the positive electrode 111 (e.g., to suppress reaction current while avoiding oxygen deficiency or cell imbalance, etc.). In this case, the current of the fuel cell stack 310 can converge to a preset minimum current or lower through the minimum flow of air supply (e.g., to achieve low load stabilization, mitigate crossover-induced degradation, or prepare for controlled voltage drops, etc.). For example, the minimum current can be set to 0.2A, but is not limited to this. Here, the rotational speed of ACP 340 and the opening values ​​of APC 350 / ACV 360 for convergence to the minimum current can be determined and set through pre-testing (e.g., during factory calibration or on-board learning) so that the current converges to the minimum current within a predetermined time, i.e., the maximum waiting time for minimum current convergence. For example, the maximum waiting time for minimum current convergence can be set to a maximum of 20 seconds or less, but this is only one implementation method. The maximum waiting time for minimum current convergence can be set differently depending on the design of those skilled in the art and the purpose and use of the fuel cell system (e.g., for commercial vehicles, stationary power sources, or auxiliary applications).

[0118] If the battery stack current converges to a minimum current, the voltage monitoring device 530 can monitor the output voltage of the battery stack (e.g., to track transient behavior and detect deviations from the expected slope curve, etc.).

[0119] The voltage drop slope calculation device 540 can calculate the drop slope of the FDC voltage. Here, the drop slope of the FDC voltage can be set so that the current potential reaches the final target potential within a predetermined time (e.g., based on the battery stack voltage characteristics during idle period, degradation state, or system calibration data, etc.). For example, when the time for the current potential to reach the final target potential after converging to the minimum current is 50 seconds (e.g., based on a pre-calibrated drop curve, thermal management requirements, or system protection standards, etc.), the battery stack voltage level after entering the idle operating state is 370V, and the final target voltage level is 324V, the drop slope of the FDC voltage can be calculated as -0.92V / second ((370V-324V) / 50 seconds) (e.g., stored in the control memory or recalculated periodically based on updates to operating conditions, etc.).

[0120] The PID controller 550 can perform PID control based on the falling slope of the FDC voltage to stably reduce the current potential to the final target potential within a predetermined time (e.g., by adjusting the valve opening to form a voltage decay curve while maintaining system stability, etc.).

[0121] When the rate of decline in tracking the FDC voltage becomes infeasible (e.g., practically impossible) due to battery stack degradation, the PID controller 550 can increase the opening of the corresponding valve (e.g., ACV 360 or APC 350) to compensate for increased internal resistance or loss of electrochemical activity, etc.

[0122] If the deviation between the target battery stack voltage and the current battery stack voltage is greater than a predetermined reference deviation, taking into account the drop slope of the FDC voltage, the PID controller 550 of this embodiment can determine that it is impossible to track the drop slope of the FDC voltage in the current valve opening state (e.g., due to insufficient airflow, membrane drying, or local overflow).

[0123] For example, the PID controller 550 can determine the valve opening adjustment value based on the voltage deviation between the target battery stack voltage and the current battery stack voltage (e.g., using proportional-integral-derivative calculations based on the magnitude, duration, and rate of change of the deviation). For example, as the voltage deviation increases, the valve opening adjustment value can be determined to be a larger value (e.g., to quickly restore voltage tracking accuracy and prevent further accumulation of deviation).

[0124] Therefore, the voltage deviation can recover quickly, allowing it to follow the falling slope of the FDC voltage again (e.g., achieving a stable voltage drop without overshoot or prolonged deviation). If the voltage deviation is greater than the reference deviation, the PID controller 550 can determine the valve opening increase required to make the battery stack voltage follow the falling slope of the FDC voltage, and can control the air flow control valve based on the determined valve opening increase (e.g., increasing the air supply via APC350 or ACV 360 through a direct command actuator).

[0125] Another example is that the PID controller 550 can calculate the slope of the battery stack voltage drop and determine the valve opening adjustment value based on the calculated slope (e.g., by comparing the actual voltage change rate with a preset slope range and selecting the appropriate valve adjustment from a predetermined control chart). For example, if the battery stack voltage drop slope is <2V / s, then α = 0.1. ° (Minimum valve resolution), 2V / s ≤ battery stack voltage drop slope < 5V / s -> α=1 ° The valve opening adjustment value based on the slope of the battery stack voltage drop can be defined in the form of a mapping table and recorded and stored in the storage device 570 (e.g., for quick lookup during real-time PID control based on dynamic battery stack conditions, etc.).

[0126] The PID controller 550 can identify whether, after increasing the valve opening, the voltage deviation drops to a reference deviation or less within a predetermined time (e.g., as a feedback condition to confirm the effectiveness of the control). If the identification result is that the voltage deviation drops to a reference deviation or less, the PID controller 550 can terminate the PID control and maintain the current state of the valve opening (e.g., to prevent oscillation or valve wear).

[0127] The PID controller 550 can repeatedly execute the PID control described above until the voltage deviation decreases to the reference deviation or less (e.g., ensuring that the drop slope of the FDC voltage is consistent throughout the idle operation).

[0128] The minimum valve opening learning device 560 can accumulate the number of times the device enters the idle running state after startup, and accumulate the number of times PID control is executed in the idle running state (e.g., using a counter or log buffer updated by the control logic).

[0129] The minimum valve opening learning device 560 can increase the minimum valve opening value based on the ratio of the cumulative PID control count to the cumulative count of entering idle operating states, i.e., the frequency of PID control execution (or entry) in the total idle count after startup (e.g., to reflect the frequency of corrective actions required and adjust the baseline airflow accordingly). For example, entry rate < 50% -> β = 0 ° 50% ≤ Entry Rate < 70% -> β = 0.2 ° 70% ≤ Entry Rate -> β = 0.5 ° Based on the PID control entry rate, the adjustment value of the minimum valve opening can be defined in the form of a mapping table and recorded and stored in the storage device 570 (e.g., to adaptively reflect the aging trend of the battery stack and reduce unnecessary control work during future idle cycles, etc.).

[0130] If the minimum valve opening value is increased, the minimum valve opening learning device 560 can initialize the cumulative idle operating state entry count and the cumulative PID control count. However, the increased minimum valve opening value can remain unchanged and can be used without modification when entering the idle operating state (e.g., to reduce the valve drive frequency and better adapt to aging battery stack conditions, etc.).

[0131] Only when the number of times the minimum valve opening enters the idle running state after startup reaches a predetermined threshold or more, such as 10 times or more, can the minimum valve opening learning device 560 control the increase of the minimum valve opening by calculating the PID control ratio (e.g., to ensure that the implementation before adjusting the control parameters is statistically significant).

[0132] When the fuel cell stack 310 is restarted, the minimum valve opening value can be initialized (e.g., to reset learned degradation parameters and re-establish baseline air control, etc.).

[0133] Figure 6 An example is shown of a method for controlling the opening of an air flow control valve in a fuel cell stack according to an embodiment of the present invention.

[0134] refer to Figure 6 The fuel cell system 300 can minimize the stack current by controlling the oxidant gas supply system when entering an idle operating state (S610). Here, the oxidant gas supply system may include... Figure 3 At least one of ACP 340, ACV360 and APC 350 (e.g., to coordinate to reduce airflow while preventing gas shortage at the positive electrode).

[0135] After the fuel cell stack current converges to a minimum current, the fuel cell system 300 can perform PID control to increase the corresponding valve opening based on the descent slope of the FDC voltage, which is based on the deviation between the target FDC voltage and the current fuel cell stack voltage, the deviation being greater than a predetermined reference value (S620). Here, the valve may include at least one of ACV 360 and APC 350 (e.g., selective control based on flow balance or pressure response, etc.).

[0136] The fuel cell system 300 can update the minimum valve opening value based on the PID control frequency relative to the cumulative number of times it has entered the idle operating state since startup (i.e., the ratio of the PID control count to the total number of times it has entered the idle operating state since startup) (S630). Subsequently, the fuel cell system 300 can perform PID control using the minimum valve opening value updated before restarting when entering the idle operating state. When the fuel cell system 300 restarts, the minimum valve opening value can be initialized (e.g., by discarding outdated learned values ​​and resetting them to factory calibration values, etc.).

[0137] Figure 7 An example is shown of a method for controlling the opening of an air flow control valve based on the falling slope of the FDC voltage in a fuel cell system according to an embodiment of the present invention.

[0138] refer to Figure 7 The fuel cell system 300 can determine whether the predetermined conditions for entering idle state are met (S710) during normal operation after startup (e.g., low current demand, vehicle stop or zero load output, etc.).

[0139] If the conditions for entering idle are met, the fuel cell system 300 can increment the count of entering idle operating state after entering idle operating state (S720). Here, the count of entering idle operating state can be initialized upon restart (e.g., to reflect the new system cycle and discard previous learning history, etc.).

[0140] The fuel cell system 300 can adjust the rotational speed of ACP 340 and the opening degree of APC 350 / ACV 360 to bring the stack current to a predetermined minimum current value (S730) (e.g., below 0.2A or other calibrated target thresholds, etc.).

[0141] The fuel cell system 300 can enter an FDC voltage slope control mode to perform FDC voltage slope control (S740 and S750) based on the stack current that converges to a minimum current value (e.g., using adaptive airflow regulation to achieve controlled voltage drop in response to stack reaction).

[0142] Here, FDC voltage slope control may include: a PID control program for increasing the corresponding valve opening; and a minimum valve opening learning program for increasing the corresponding minimum valve opening value based on the battery stack degradation (e.g., adjusting the long-term airflow strategy to reflect aging effects). FDC voltage slope control will be achieved through the following... Figure 8 The description becomes clearer.

[0143] The fuel cell system 300 can terminate the descent slope control of the FDC voltage and perform medium / long-term control based on the stack voltage, wherein the stack voltage is reduced to a first target voltage via FDC voltage slope control (S760 to S780). This will be explained here with reference to the following description. Figure 9 To describe in detail the medium / long-term control (e.g., addressing steady-state airflow, long-term idle management, and moisture treatment strategies).

[0144] Figure 8 An example of a method for controlling the opening of an air flow control valve based on the falling slope of the FDC voltage in a fuel cell system according to another embodiment of the present invention is shown.

[0145] Specifically, Figure 8 Show Figure 7 An example of a detailed process for operating the S750.

[0146] refer to Figure 8 When entering FDC slope control mode, fuel cell system 300 can identify the count of accumulated idle operation state after startup, the accumulated PID control count, and the minimum valve opening value (S801) (e.g., retrieved from stored operation history or non-volatile memory).

[0147] The fuel cell system 300 can acquire the current stack voltage value (S803) (e.g., from a high-resolution voltage monitoring circuit or sensor 370, etc.).

[0148] The fuel cell system 300 can identify the current target voltage value based on the slope of the FDC voltage drop (S805) (e.g., by calculating the expected value at a given time point on a preset slope curve).

[0149] The fuel cell system 300 can calculate the voltage deviation DV, which is the difference between the current stack voltage value and the current target voltage value (S807).

[0150] The fuel cell system 300 can compare DV with a predetermined reference deviation γ (S809) (e.g., to determine whether PID intervention is needed, e.g., if DV > γ = 2V, etc.).

[0151] The comparison shows that if DV is greater than γ, the fuel cell system 300 can determine that it cannot follow the FDC slope voltage control, and can calculate the corresponding valve opening adjustment value α (S811). Here, the valve may include at least one of APC 350 and ACV 360 (e.g., selected based on their control resolution, dynamic range, or airflow sensitivity, etc.).

[0152] The fuel cell system 300 can perform PID control on the corresponding valve based on the adjustment value α, and increment the PID control count (S813). Here, the current valve opening value is A. i The valve opening value A is adjusted upward by PID control. i+1 Formula A i+1 =A i+α Calculate. Here, "i" can be a natural number including 0, and A0 is A. init It is an evaluation setting based on the initial state of the battery stack (e.g., factory settings or previously learned baselines).

[0153] If the count of entering the idle operating state is greater than or equal to the predetermined minimum number of samples, the fuel cell system 300 can calculate the minimum valve opening adjustment value β (S815 to S817) based on the ratio of the PID control count value to the count of entering the idle operating state (e.g., to update the learned minimum valve opening used in subsequent idle periods).

[0154] If the count of entering the idle operation state is less than the predetermined minimum number of samples, the fuel cell system 300 can re-enter operation S803 (e.g., to continue collecting runtime data until there are enough samples available for learning, etc.).

[0155] The fuel cell system 300 can increase the current minimum valve opening value based on the calculated minimum valve opening adjustment value β (S819). Here, the current minimum valve opening value is B. i The updated minimum valve opening value is B. i+1 When, formula B can be calculated. i+1 =B i +β. Here, "i" is a natural number including 0, and B0 is B. init , which is 0 (for example, representing the reference valve opening during system debugging).

[0156] If the minimum valve opening value is increased, the fuel cell system 300 can initialize the idle operation state count and PID control count (S821) (e.g., start a new learning cycle with the updated baseline).

[0157] In operation S809, when DV is less than or equal to γ, the fuel cell system 300 can determine to follow the FDC slope voltage control to maintain the current valve opening state (S823) (e.g., to avoid unnecessary control adjustments or valve wear).

[0158] In this embodiment, the minimum valve opening value can remain unchanged when re-entering the idle operating state, and it can only be initialized upon restart. For example, during restart, based on A... init and B init A cycle of operations S803 to S821 can be executed (e.g., to ensure repeatable initial behavior after the vehicle is powered off).

[0159] Figure 9 An example is shown of controlling the opening of an air flow control valve based on the falling slope of the FDC voltage in a fuel cell system according to an embodiment of the present disclosure.

[0160] Reference numeral 910 illustrates valve opening control when, after entering idle operation, there is no voltage deviation greater than or equal to a reference value due to battery stack degradation during a voltage drop based on the FDC slope (e.g., indicating that the system can follow the target voltage curve without PID correction, which indicates minimal degradation effects, etc.). Reference numeral 920 illustrates valve opening control when, after entering idle operation, there is no voltage deviation greater than or equal to a reference value due to battery stack degradation during a voltage drop based on the FDC slope, PID control is executed to increase the corresponding valve opening value (e.g., air control reflecting correction under aging conditions to follow a predetermined slope, etc.).

[0161] The control section in the idle operation state can be roughly divided into the initial section, short-term section, medium-term section and long-term section (e.g., based on the time since entering the idle state or the system voltage / current, etc.).

[0162] Referring to reference numeral 910, after the fuel cell stack enters a shutdown state (i.e., idle operation), the fuel cell system 300 can control the airflow to bring the stack current to a minimum of 0.2A within an initial control period of up to 20 seconds (e.g., to stabilize the electrochemical reaction under minimum load and prepare for a controlled voltage drop). In this case, ACP 340 can be reduced to a minimum of 15,000 RPM, and the opening values ​​of APC 350 and ACV 360 can be reduced from the existing 45 degrees to 5 degrees (e.g., to reduce or minimize the oxidant flow while maintaining sufficient airflow to prevent cathode misgassing or pressure imbalance, etc.). If the stack current converges to the minimum current according to the initial control period, the stack voltage can drop from the initial 370V and reach 324V at a rate of 0.92V / s within a short control period of up to 60 seconds, depending on the FDC voltage drop slope (e.g., to ensure controlled voltage drop to avoid rapid potential changes that could lead to membrane stress or water accumulation, etc.). Here, in the initial control section and the short-term control section, the hydrogen pressure can be kept constant at 130 kPa (e.g., to ensure a stable hydrogen supply and avoid excessive purging).

[0163] From the intermediate control phase to the initial air purging, the hydrogen pressure can be increased to 150 kPa and maintained for 150 seconds. During this time, the ACP 340 can be stopped, and the valve openings of APC 350 and ACV 360 can be increased to 50 degrees and 45 degrees, respectively (e.g., to promote effective gas exchange, remove residual moisture, and prevent localized overflow of the battery stack). During FDV 170 purging, the valves of APC 350 can be closed, and ACP 340 can be temporarily driven at the lowest speed. When cleaning is complete and the system enters the long-term control zone, all flow control valves are closed, and the ACP 340 is stopped (e.g., to maintain the battery stack in a sealed, low-flow idle state under storage or humidification conditions).

[0164] As shown in reference numeral 921 within reference numeral 920, if the fuel cell stack voltage fails to follow the FDC slope and the voltage deviation from the target voltage is greater than or equal to a reference value (as shown in reference numeral 922), the fuel cell system 300 can control the stack voltage to follow the FDC slope again by increasing the opening of ACV 360 and APC 350 (which are air flow control valves) to 6 degrees (e.g., to enhance air supply, promote proper reactant distribution, reduce potential deviations due to insufficient oxidant availability, etc.). This is done by providing a smaller but sufficient increase in airflow to restore voltage tracking without overshooting. For example, the fuel cell system 300 can estimate the rate of decline of the FDC voltage by performing PID control on the air flow control valves based on the stack degradation (e.g., dynamically adjusting the slope based on historical voltage response and corrective airflow implementation, etc.).

[0165] Figure 10 An example of a computing device according to an embodiment of the present disclosure is shown.

[0166] refer to Figure 10 The computing device 1000 may include at least one of a processor 1020, a memory 1030, a user interface input device 1040, a user interface output device 1050, a storage device 1060, and a network interface 1070, which are connected via a bus 1010 (e.g., to support data flow between system components and external interfaces).

[0167] Processor 1020 may be a central processing unit (CPU) or a semiconductor device that processes instructions stored in memory 1030 and / or storage device 1060. Memory 1030 and storage device 1060 may include various types of volatile or non-volatile storage media. For example, memory 1030 may include read-only memory (ROM) 1031 and random access memory (RAM) 1032 (e.g., for storing executable firmware and runtime data buffers, etc., respectively).

[0168] Therefore, the operation of the methods (or programs) or algorithms described in conjunction with the embodiments disclosed herein can be directly implemented by hardware modules, software modules, or a combination of hardware and software modules, executed by processor 1020. Software modules can reside in storage media (e.g., memory 1030 and / or storage device 1060), such as RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disks, removable disks, and optical disc (CD)-ROMs. For example, processor 1020 can form part of the aforementioned fuel cell vehicle system and can correspond to... Figure 2 The controller (ECU) 70 and / or Figure 3The fuel cell controller 380 (e.g., performs control logic such as valve regulation, stack protection and slope tracking in real time).

[0169] An exemplary storage medium may be coupled to processor 1020, and processor 1020 may read information from and write information to the storage medium. Alternatively, the storage medium may be integrated with processor 1020. The processor and storage medium may reside within an application-specific integrated circuit (ASIC). The ASIC may also reside in an onboard controller (e.g., for real-time execution of fuel cell control logic, fuel cell stack monitoring, and airflow regulation). Alternatively, processor 1020 and storage medium may also reside as separate components within a vehicle controller or vehicle fuel cell system (e.g., as part of a distributed embedded architecture where memory and processing functions are handled by separate modules communicating via networks such as CAN or Ethernet).

[0170] One aspect of this disclosure provides a method and apparatus for controlling the opening degree of an air flow control valve in a fuel cell stack.

[0171] Another aspect of this disclosure provides a method and apparatus for adaptively controlling the opening degree of an air flow control valve based on the degradation of the fuel cell stack in a fuel cell system entering an idle operating state.

[0172] Another aspect of this disclosure provides a method and apparatus for controlling the opening of an air flow control valve in a fuel cell stack. The method minimizes the stack current in the idle operating state and then performs proportional-integral-derivative (PID) control on the air flow control valve based on the voltage drop slope of the fuel cell DC-DC converter (hereinafter referred to as "FDC"). This minimizes the appearance of droplets in the stack and thus prevents stack degradation in advance.

[0173] Another aspect of this disclosure provides a method and apparatus for controlling the opening degree of an air flow control valve in a fuel cell stack. The method can improve the following performance of the FDC voltage drop slope by adaptively increasing the minimum valve opening value of the oxidant gas supply system valve, and can improve valve durability by reducing the PID control frequency based on the ratio of PID control after startup to the count of entering the idle operating state.

[0174] The technical problems to be solved by this disclosure are not limited to those mentioned above. Those skilled in the art to which this disclosure pertains will clearly understand any other technical problems not mentioned herein from the following description.

[0175] According to one aspect of this disclosure, a method for controlling the opening of an air flow control valve in a fuel cell system includes: controlling the stack current to converge to a predetermined minimum current based on the start-up and entry into an idle operating state; and controlling the rate of decrease of the fuel cell DC-DC converter (FDC) voltage based on the convergence of the stack current to the minimum current.

[0176] As one implementation, the method may further include: performing proportional-integral-derivative (PID) control on the air flow control valve by monitoring the battery stack voltage; and increasing the minimum valve opening value of the air flow control valve based on the degree of degradation of the battery stack, wherein the degree of degradation can be determined based on the PID control entry count.

[0177] In one implementation, the air flow rate control valve may include an air shut-off valve (ACV), which is a valve that blocks the supply of air to the battery stack, and an air pressure control valve (APC), which is a valve that controls the air pressure.

[0178] As one implementation, performing PID control may include: acquiring the current output voltage value of the battery stack; acquiring the target battery stack voltage value corresponding to the current output voltage value; and calculating the voltage deviation between the target battery stack voltage value and the current output voltage value, wherein PID control may be performed based on the voltage deviation being greater than a predetermined reference deviation.

[0179] As one implementation, the target battery stack voltage value corresponding to the current output voltage value can be determined based on the falling slope of the FDC voltage corresponding to the idle operating state.

[0180] As one implementation, the rate of decrease of the FDC voltage can be determined by (ba) / t based on the battery stack output voltage a after entering the idle operation state, the final target voltage b according to the rate of decrease of the FDC voltage, and the maximum waiting time t to reach the final target voltage.

[0181] As one implementation, performing PID control may further include: if the voltage deviation is greater than a reference deviation, determining a valve opening increase value required to make the battery stack voltage follow the falling slope of the FDC voltage; and controlling the air flow control valve based on the determined valve opening increase value.

[0182] As one implementation, increasing the minimum valve opening value may include: counting the number of times the valve enters the idle operating state after startup; counting the PID control count in the idle operating state; calculating the ratio of the PID control count after startup to the count in the idle operating state; and determining the minimum valve opening adjustment value based on the ratio.

[0183] As one implementation, the ratio can be calculated based on the number of times the system enters an idle running state after startup, and this ratio is greater than a predetermined reference value.

[0184] As one implementation, if the voltage deviation is less than or equal to a predetermined reference deviation, it can be determined that the rate of drop of the FDC voltage is being followed normally, and thus the opening state of the air flow control valve can be maintained.

[0185] As one implementation, the minimum valve opening value can be initialized upon restart.

[0186] According to another aspect of this disclosure, the computing device provided in the fuel cell system includes a processor for executing instructions and a memory for storing instructions, wherein the executed instructions are used to perform control to cause the stack current to converge to a predetermined minimum current based on the start-up and idle operation state, and to control the descent slope of the fuel cell DC-DC converter (FDC) voltage based on the stack current converging to the minimum current.

[0187] As one implementation, the processor can perform proportional-integral-derivative (PID) control on the air flow control valve by monitoring the voltage of the battery stack, and increase the minimum valve opening value of the air flow control valve based on the degree of degradation of the battery stack, which can be determined based on the PID control input count.

[0188] In one implementation, the air flow control valve may include: an air shut-off valve (ACV) for blocking the supply of air to the battery stack; and an air pressure control valve (APC) for controlling the air pressure.

[0189] In one implementation, the processor can acquire the current output voltage value of the battery stack, identify the target battery stack voltage value corresponding to the current output voltage value, calculate the voltage deviation between the target battery stack voltage value and the current output voltage value, and perform PID control based on the voltage deviation being greater than a predetermined reference deviation.

[0190] As one implementation method, the target battery stack voltage value corresponding to the current output voltage value can be determined based on the falling slope of the FDC voltage corresponding to the idle operating state.

[0191] As one implementation, the rate of decrease of the FDC voltage can be determined by (ba) / t based on the battery stack output voltage a after entering the idle operating state, the final target voltage b according to the rate of decrease of the FDC voltage, and the maximum waiting time t to reach the final target voltage.

[0192] As one implementation, if the voltage deviation is greater than the reference deviation, the processor can determine the valve opening increase value required for the battery stack voltage to follow the falling slope of the FDC voltage, and control the air flow control valve based on the determined valve opening increase value.

[0193] In one implementation, the processor can count the number of times the device enters the idle running state after startup, count the number of times the PID control is activated in the idle running state, calculate the ratio of the number of times the PID control is activated after startup to the number of times the device enters the idle running state, and determine the minimum valve opening adjustment value based on this ratio.

[0194] As one implementation, the processor can calculate the ratio based on the number of times it enters an idle running state after startup, and this ratio is greater than a predetermined reference value.

[0195] As one implementation, if the voltage deviation is less than or equal to a predetermined reference deviation, the processor can determine that the rate of drop of the FDC voltage is being followed normally and execute control to maintain the opening state of the air flow control valve.

[0196] As one implementation, the minimum valve opening value can be initialized upon restart.

[0197] This technology provides a method and apparatus for controlling the opening degree of an air flow control valve in a fuel cell stack.

[0198] Furthermore, this technology can adaptively control the opening of the air flow control valve based on the degradation status of the fuel cell stack in a fuel cell system that has entered an idle operating state, thereby preventing fuel cell stack degradation.

[0199] Furthermore, this technology can minimize the presence of droplets in the battery stack by using PID control of the air flow control valve based on the rate of drop of the FDC voltage after minimizing the battery stack current in the idle operating state, thereby preventing battery stack degradation.

[0200] Furthermore, this technology can improve valve durability by enhancing the tracking performance of the FDC voltage drop slope and by adaptively increasing the minimum valve opening value of the oxidizing gas supply system valves based on the ratio of PID control counts after startup to counts entering idle operation.

[0201] In addition, various effects can be provided, either directly or indirectly, through this article.

[0202] The above description is only for illustrating the technical spirit of this disclosure. Those skilled in the art can make various modifications and changes without departing from the essential characteristics of this disclosure.

[0203] Therefore, the embodiments disclosed herein are not intended to limit the technical spirit of this disclosure, but rather to describe it, and the scope of the technical spirit of this disclosure is not limited by these embodiments. The scope of protection of this disclosure should be interpreted by the appended claims, and all technical spirit within the scope of the appended claims should be interpreted as being included within the scope of this disclosure.

Claims

1. A method performed by a device of a fuel cell system, the method comprising the following steps: After the fuel cell system is started, the fuel cell stack in the fuel cell system enters an idle operating state. The airflow to the fuel cell stack is controlled so that the current of the fuel cell stack converges to a predetermined current. Based on the convergence of the fuel cell stack current to a predetermined current, the voltage drop slope of the fuel cell DC-DC converter (FDC) is controlled; and The operation of the fuel cell stack is controlled based on the controlled descent slope of the FDC voltage.

2. The method according to claim 1, further comprising the following step: Based on the voltage of the fuel cell stack, feedback-based control is performed on the air flow control valve of the fuel cell system; as well as Based on the degradation level of the fuel cell stack, the valve opening value of the air flow control valve is increased. The degradation level of the fuel cell stack is determined by the number of times feedback-based control is executed during the idle operation of the fuel cell stack.

3. The method according to claim 2, wherein, The air flow control valve includes: An air shut-off valve (ACV) is a valve configured to block the supply of air to the fuel cell stack. A pneumatic control valve (APC) is a valve configured to control pneumatic pressure.

4. The method according to claim 2, wherein, The steps for implementing feedback-based control include: Obtain the current output voltage value of the fuel cell stack; Obtain the target output voltage value of the fuel cell stack associated with the current output voltage value; and Identify the voltage deviation between the target output voltage value and the current output voltage value, and In this process, feedback-based control is performed based on the voltage deviation being greater than a predetermined reference deviation.

5. The method according to claim 4, wherein, The target output voltage value is determined based on the falling slope of the FDC voltage, wherein the falling slope of the FDC voltage is applied during the idle operation of the fuel cell stack.

6. The method according to claim 5, wherein, The rate of decrease of the FDC voltage is determined based on the following: The output voltage value of the fuel cell stack after entering the idle operating state. Target output voltage value, and The predetermined waiting time to reach the target output voltage value.

7. The method according to claim 5, wherein, The implementation of feedback-based control steps also includes: Based on the voltage deviation being greater than a predetermined reference deviation, determine the valve opening adjustment value required to make the current output voltage value of the fuel cell stack follow the decreasing slope of the FDC voltage; and The air flow control valve is controlled based on the determined valve opening adjustment value.

8. The method according to claim 2, wherein, The steps to increase the valve opening value include: After the fuel cell system is started, the number of times the fuel cell stack enters an idle operating state is counted; The number of times feedback-based control is executed during the idle operation of the fuel cell stack is counted; Calculate the ratio of the number of times feedback-based control was executed to the number of times the idle running state was entered; and The valve opening adjustment value is determined based on this ratio, and The ratio is calculated based on the number of times the system enters an idle running state after startup being greater than a predetermined reference value.

9. The method according to claim 4, further comprising the following step: Based on the voltage deviation being less than or equal to a predetermined reference deviation, the output voltage value of the fuel cell stack is determined to be within the voltage value range determined by the falling slope of the FDC voltage. as well as Control the airflow control valve to maintain the current opening.

10. The method of claim 2, further comprising the step of: When the fuel cell system restarts, the valve opening value of the air flow control valve is initialized.

11. An apparatus for a fuel cell system, the apparatus comprising: processor; as well as A memory that stores at least one instruction, which, when executed by a processor in communication with the memory, is configured to cause the device to: After the fuel cell system starts up, the fuel cell stack enters an idle operating state. The airflow to the fuel cell stack is controlled to cause the current in the fuel cell stack to converge to a predetermined current. The voltage drop slope of the fuel cell DC-DC converter (FDC) is controlled based on the convergence of the current in the fuel cell stack to a predetermined current.

12. The apparatus according to claim 11, wherein, When the processor communicating with the memory executes at least one instruction, the at least one instruction is configured to cause the device to: Based on the voltage of the fuel cell stack, feedback-based control is performed on the air flow control valve of the fuel cell system, and Based on the degradation level of the fuel cell stack, the valve opening value of the air flow control valve is increased, and The degradation level of the fuel cell stack is determined based on the number of times feedback-based control is executed during the idle operation of the fuel cell stack.

13. The apparatus according to claim 12, wherein, The air flow control valve includes: An air shut-off valve (ACV) is a valve configured to block the supply of air to the fuel cell stack. A pneumatic control valve (APC) is a valve configured to control pneumatic pressure.

14. The apparatus according to claim 12, wherein, When the processor communicating with the memory executes at least one of the instructions, the at least one instruction is configured to cause the device to perform the feedback-based control in such a way that: Obtain the current output voltage value of the fuel cell stack. Obtain the target output voltage value of the fuel cell stack associated with the current output voltage value, and Identify the voltage deviation between the target output voltage value and the current output voltage value, and In this process, feedback-based control is performed based on the voltage deviation being greater than a predetermined reference deviation.

15. The apparatus according to claim 14, wherein, The target output voltage value is determined based on the falling slope of the FDC voltage, wherein the falling slope of the FDC voltage is applied during the idle operating state of the fuel cell stack.

16. The apparatus according to claim 15, wherein, The rate of decrease of the FDC voltage is determined based on the following: The output voltage value of the fuel cell stack after entering the idle operating state. Target output voltage value, and The predetermined waiting time to reach the target output voltage value.

17. A method performed by a device of a fuel cell system, the method comprising the steps of: Based on the detection that the fuel cell stack of the fuel cell system has entered an idle operating state, the air supply to the fuel cell stack is reduced to lower the current of the fuel cell stack; Based on the current of the fuel cell stack decreasing to a predetermined threshold, the voltage of the fuel cell stack is controlled to follow a predetermined voltage drop curve during the idle operation state. The air supply conditions are adjusted based on the deviation between the voltage of the fuel cell stack and the reference voltage. as well as The operation of the fuel cell system is controlled based on the adjusted air supply conditions.

18. The method according to claim 17, wherein, The adjustment of air supply conditions includes: adjusting the opening of the air flow control valve of the fuel cell system based on the deviation.

19. The method of claim 17, further comprising the step of: The control parameters of the air supply conditions are updated based on the adjustment frequency of the fuel cell stack during the various idle operating states.

20. The method of claim 17, wherein, A predetermined voltage drop curve is defined based on the difference between the initial voltage of the fuel cell stack and the target output voltage value, as well as the duration for which the target output voltage value is reached.

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