Fuel cell system, air control method and equipment thereof and storage medium

Abstract

The invention relates to a fuel cell system, an air control method and equipment thereof and a storage medium. The system comprises an air compressor, a back pressure valve, a discharge valve and a controller. And the discharge valve forms a discharge branch by connecting an outlet of the air compressor and a discharge pipeline of the exhaust pipe. The controller is used for controlling the opening degree of the discharge valve and the rotating speed of the air compressor to actively prevent surge by comparing the real-time pressure ratio of the air compressor with the surge risk critical pressure ratio determined based on a Map map of the flow and the rotating speed of the air compressor in the plateau environment. Meanwhile, by comparing the real-time pressure of the cathode inlet of the electric pile with the target set pressure of the cathode inlet of the electric pile, the opening degree of a back pressure valve is controlled to stabilize the pressure of the electric pile; therefore, by means of functional decoupling and cooperative control of the discharge valve and the back pressure valve, on the premise that the operation condition of the electric pile does not need to be reduced, surge of the air compressor is effectively avoided, and high-performance and high-reliability operation of the fuel cell system in the plateau environment is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell, and in particular to a fuel cell system, an air control method, equipment and storage medium thereof. BACKGROUND

[0002] The air compressor is one of the core components of the air supply system of the fuel cell, and the flow rate and pressure output thereof directly affect the oxygen concentration and partial pressure in the fuel cell system, and further affect the efficiency, stability and dynamic performance of the fuel cell system. In the industry, the air compressor not only needs to meet the air flow rate and pressure requirements under the conventional working condition, but also needs to meet the use requirements of the fuel cell vehicle under different application scenarios, such as the three-high environmental adaptability requirements under high temperature, high cold and high altitude conditions.

[0003] The performance of the fuel cell is very sensitive to the cathode pressure and flow rate, especially in the plateau environment. Compared with the standard atmospheric condition, the oxygen content and pressure of the plateau atmosphere are greatly reduced. In order to alleviate the influence of the great reduction of the plateau atmospheric pressure, the demand for the pressure ratio of the air compressor of the vehicle-mounted fuel cell system is significantly improved, which is easy to cause the surge of the air compressor.

[0004] In the related technology, the air compressor speed and the opening degree of the back pressure valve are adjusted to adjust the inlet set pressure of the stack by adjusting the air metering ratio and the cathode inlet set pressure of the fuel cell system stack. With the continuous reduction of the environmental pressure with the increase of the altitude, the pressure ratio of the air compressor is continuously increased, which is easy to cause the surge of the air compressor. Generally, in order to avoid the surge of the air compressor, the cathode inlet set pressure of the stack is reduced, which leads to the reduction of the performance of the stack. SUMMARY

[0005] The embodiments of the present application provide a fuel cell system, an air control method, equipment and storage medium thereof, to solve the problem that in the related technology, in order to suppress the surge of the air compressor in the high-altitude environment, the cathode inlet set pressure of the stack is reduced, which leads to the reduction of the performance of the stack.

[0006] In a first aspect, a fuel cell system is provided, comprising: a stack inlet air path comprising an air compressor; a stack outlet air path comprising a back pressure valve; an exhaust pipe connected with the back pressure valve for exhausting to the atmosphere; a bleeder valve connected with the exhaust pipe through a bleeder pipeline connected with the outlet of the air compressor; a controller connected with the air compressor, the back pressure valve and the bleeder valve, the controller being configured to control the opening degree of the bleeder valve and the speed of the air compressor to regulate the air compressor pressure ratio of the air compressor, and the controller being further configured to control the opening degree of the back pressure valve to adjust the exhaust back pressure of the stack outlet air path.

[0007] In some embodiments, the air inlet path further comprises an air filter upstream of the air compressor, an air compressor inlet temperature pressure flow sensor, and a intercooler, a humidifier, an inlet cutoff valve, an air inlet temperature pressure sensor downstream of the air compressor; and The bleed pipe is connected to a pipe between the air compressor outlet and the humidifier.

[0008] In some embodiments, the air outlet path further comprises an air outlet pressure sensor, an outlet cutoff valve, a humidity control valve connected in sequence, and an outlet of the humidity control valve connected to the back pressure valve.

[0009] In a second aspect, an air control method for a fuel cell system is provided, which comprises: Obtaining a target air compressor inlet equivalent flow rate and a real-time air compressor pressure ratio; Determining a surge risk critical pressure ratio based on a surge protection curve in a Map of air compressor flow rate versus rotational speed and in combination with the target air compressor inlet equivalent flow rate; Comparing the real-time air compressor pressure ratio with the surge risk critical pressure ratio, and then controlling the opening degree of the bleed valve and the rotational speed of the air compressor to regulate the air compressor pressure ratio according to the comparison result, while comparing the real-time pressure at the cathode inlet of the stack with a target set pressure at the cathode inlet of the stack, and adjusting the opening degree of the back pressure valve according to the comparison result.

[0010] In some embodiments, when the real-time air compressor pressure ratio is greater than the surge risk critical pressure ratio, the controller is used to control the bleed valve to open to a target opening degree, while the air compressor is controlled to increase the rotational speed.

[0011] In some embodiments, the air compressor is controlled to increase the rotational speed, which specifically comprises the following steps: Obtaining the bleed flow rate of the bleed valve; Adding the real-time air compressor inlet flow rate and the bleed flow rate to obtain the target air compressor inlet flow rate; Obtaining a real-time rotational speed corresponding to the real-time air compressor inlet flow rate and a target rotational speed corresponding to the target air compressor inlet flow rate based on a Map of air compressor flow rate versus rotational speed; Controlling the air compressor to adjust from the real-time rotational speed to the target rotational speed.

[0012] In some embodiments, the air inlet path of the fuel cell system further comprises an air filter upstream of the air compressor, an air compressor inlet temperature pressure flow sensor, and a intercooler, a humidifier, an inlet cutoff valve, an air inlet temperature pressure sensor downstream of the air compressor; and the bleed pipe is connected to a pipe between the air compressor outlet and the humidifier; Obtaining the bleed flow rate of the bleed valve, which specifically comprises the following steps: The real-time air compressor inlet flow is obtained by using an air compressor inlet temperature, pressure and flow sensor, and the leakage flow is calculated by combining the calibrated leakage coefficient.

[0013] In some embodiments, the air inlet path of the fuel cell system further comprises an air filter upstream of the air compressor, an air compressor inlet temperature, pressure and flow sensor, a intercooler downstream of the air compressor, a humidifier, an air inlet cutoff valve, an air inlet temperature and pressure sensor; the leakage pipeline is connected to the pipeline between the air compressor outlet and the humidifier; a leakage flow sensor is arranged on the leakage pipeline; The leakage flow of the leakage valve is obtained by using the leakage flow sensor.

[0014] In some embodiments, when the real-time air compressor pressure ratio is less than the critical pressure ratio of surge risk, the controller is used to control the leakage valve to maintain a closed state, and the target air compressor inlet flow is obtained by adding the real-time air compressor inlet flow and the leakage flow; the target speed corresponding to the target air compressor inlet flow is obtained based on the Map diagram of air compressor flow and speed, and then the controller controls the air compressor to operate at the target speed.

[0015] In some embodiments, the target air compressor inlet equivalent flow and the real-time air compressor pressure ratio are obtained, and the specific steps include: The real-time ambient temperature, ambient pressure, air compressor inlet temperature and air compressor inlet pressure of the air compressor, and the real-time pressure of the fuel cell air inlet are obtained; The target air compressor inlet flow is calculated according to the set value corresponding to the air flow of the fuel cell air inlet; the target air compressor inlet equivalent flow is calculated by using the real-time ambient temperature, ambient pressure, air compressor inlet temperature and air compressor inlet pressure of the air compressor, and the target air compressor inlet flow, and combining the equivalent flow formula; The real-time air compressor outlet pressure is calculated based on the real-time pressure of the fuel cell air inlet and the calibrated pressure loss; then the real-time air compressor pressure ratio is calculated based on the real-time air compressor outlet pressure and the air compressor inlet pressure.

[0016] In some embodiments, the real-time pressure of the cathode inlet of the stack is compared with the target set pressure of the cathode inlet of the stack, and the opening of the back pressure valve is adjusted according to the comparison result, and the specific steps include: The real-time pressure of the cathode inlet of the stack is obtained by using the air inlet temperature and pressure sensor; The real-time pressure of the cathode inlet of the stack is compared with the target set pressure of the cathode inlet of the stack; If the real-time pressure of the cathode inlet of the stack is less than the target set pressure of the cathode inlet of the stack, the opening of the back pressure valve is controlled to decrease based on the difference between the real-time pressure of the cathode inlet of the stack and the target set pressure of the cathode inlet of the stack. If the real-time pressure at the cathode inlet of the fuel cell stack is greater than the target set pressure at the cathode inlet of the fuel cell stack, the back pressure valve opening is increased based on the difference between the real-time pressure at the cathode inlet of the fuel cell stack and the target set pressure at the cathode inlet of the fuel cell stack.

[0017] In some embodiments, the following steps are also included: Obtain the real-time converted flow rate at the air compressor inlet; Based on the surge curve in the air compressor flow and speed map, the critical pressure ratio for surge fault is determined according to the real-time reduced flow rate at the air compressor inlet. The controller is used to compare the real-time air compressor pressure ratio with the critical pressure ratio for surge faults; When the real-time air compressor pressure ratio is greater than the critical pressure ratio for surge fault, the controller is used to open the relief valve to the target opening degree, and the air compressor is shut down at the same time.

[0018] In some embodiments, the air compressor flow rate versus speed map includes surge protection curves at different altitudes; Obtaining the surge protection curve from the air compressor flow rate and speed Map diagram specifically includes the following steps: Obtain the altitude of the current location of the air compressor, and then determine the corresponding surge protection curve based on the altitude.

[0019] Thirdly, an air control device for a fuel cell system is provided, the air control device for the fuel cell system including a processor, a memory, and an air control program for the fuel cell system stored in the memory and executable by the processor, wherein when the air control program for the fuel cell system is executed by the processor, the steps of an air control method for the fuel cell system are implemented.

[0020] Fourthly, a computer-readable storage medium is provided, on which an air control program for a fuel cell system is stored, wherein when the air control program for the fuel cell system is executed by a processor, the steps of an air control method for the fuel cell system are implemented.

[0021] The beneficial effects of the technical solution provided in this application include: This application provides a fuel cell system and its air control method, device, and storage medium. The system's exhaust pipe is connected to the back pressure valve of the outgoing gas path for discharging exhaust gas to the outside atmosphere. A vent valve is connected to the exhaust pipe via a vent pipe connected to the air compressor outlet of the incoming gas path. A controller is signal-connected to the air compressor, back pressure valve, and vent valve. The controller controls the air flow rate released by the vent valve in high-altitude environments to regulate the air compressor pressure ratio while maintaining the air flow rate and pressure entering the fuel cell stack at set values. By adding a vent pipe at the air compressor outlet and controlling the vent valve opening, a certain amount of air flow is released, ensuring the air flow rate and pressure entering the stack while preventing air compressor surge. Furthermore, the real-time pressure at the stack cathode inlet can be compared with the target set pressure at the stack cathode inlet, and the opening of the back pressure valve can be adjusted based on the comparison result. This achieves decoupling of the back pressure valve's pressure regulation function and the air compressor's anti-surge protection function in the control logic. The back pressure valve is dedicated to maintaining the performance of the fuel cell stack, while the vent valve is dedicated to ensuring the stable operation of the air compressor. Through the coordinated scheduling of the controller, the two work together to resolve the contradiction between maintaining the high performance of the fuel cell stack and avoiding air compressor surge in high-altitude environments. Thus, even in high-altitude environments, the air metering ratio and cathode inlet set pressure of the fuel cell system stack remain unchanged, preventing the performance of the fuel cell stack from degrading. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a fuel cell system provided in an embodiment of this application; Figure 2 A schematic diagram of surge protection curve and surge curve in the air compressor flow rate and speed map provided in the embodiments of this application; Figure 3 This application provides schematic diagrams illustrating the operation of an air compressor at different altitudes, as shown in the embodiments of this application. Figure 4 This is a schematic flowchart of an air control method for a fuel cell system provided in an embodiment of this application.

[0024] In the diagram: 1. Air compressor; 2. Back pressure valve; 3. Exhaust pipe; 4. Drain valve; 5. Controller; 6. Air filter; 7. Air compressor inlet temperature, pressure and flow sensor; 8. Intercooler; 9. Humidifier; 10. Reactor inlet shut-off valve; 11. Air inlet temperature and pressure sensor; 12. Air outlet pressure sensor; 13. Reactor outlet shut-off valve; 14. Humidity control valve. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] It should be understood in connection with this application that: Fuel cell performance is highly sensitive to cathode pressure and flow rate, especially in high-altitude environments where oxygen levels and pressures are significantly lower than in standard atmospheric conditions. To mitigate the impact of this drastic pressure drop at high altitudes, the onboard fuel cell system demands a significantly higher air compressor pressure ratio, which can easily lead to compressor surge.

[0027] The problem that needs to be solved is: How to ensure the performance of the fuel cell stack in a high-altitude environment and avoid compressor surge? In the relevant solutions, the fuel cell stack inlet set pressure is adjusted by regulating the air metering ratio and cathode inlet set pressure of the fuel cell system stack, as well as the compressor speed and back pressure valve opening. However, maintaining the cathode inlet set pressure is crucial. As altitude increases and ambient pressure decreases, the compressor pressure ratio continuously increases, easily triggering compressor surge. If the cathode inlet set pressure is lowered to avoid compressor surge, the stack performance will degrade. The overall approach is to prioritize ensuring the compressor's operating conditions while appropriately lowering the stack's operating conditions.

[0028] This leads to a reduction in fuel cell stack performance, so the new problem is how to avoid compressor surge without reducing fuel cell stack performance? Therefore, under this line of thinking, the technical direction of this application is: In high-altitude environments, while maintaining the air metering ratio and cathode inlet set pressure of the fuel cell system stack, a certain amount of air flow is released by adding a vent branch at the air compressor outlet and controlling the vent valve opening. This ensures the air flow and pressure entering the stack while preventing air compressor surge. The overall approach prioritizes ensuring the operating conditions of the fuel cell stack, and then ensures the operating conditions of the air compressor by releasing a certain amount of air. The specific solution is explained below: This application provides an air control device and method for a fuel cell to solve the problem in related technologies where the performance of the fuel cell stack is reduced due to lowering the set pressure at the cathode inlet of the fuel cell stack in order to suppress compressor surge in high-altitude environments.

[0029] Firstly, please refer toFigure 1 An air control device for a fuel cell, comprising: The inlet gas path includes an air compressor 1; The outlet gas path includes back pressure valve 2; Exhaust pipe 3, which is connected to back pressure valve 2, is used to exhaust gas to the outside atmosphere; The relief valve 4 is connected to the exhaust pipe 3 via a relief pipe connected to the outlet of the air compressor 1; The controller 5 is connected to the air compressor 1, the back pressure valve 2 and the relief valve 4. The controller 5 is used to control the opening degree of the relief valve 4 and the speed of the air compressor 1 to regulate the air compressor pressure ratio of the air compressor 1. The controller 5 is also used to control the opening degree of the back pressure valve 2 to adjust the exhaust back pressure of the reactor gas path.

[0030] By adding a venting pipe to the outlet of air compressor 1 and controlling the opening of venting valve 4, a certain amount of air flow is released. This ensures the air flow and pressure entering the stack while preventing air compressor surge. Thus, even in high-altitude environments, the air metering ratio and cathode inlet set pressure of the fuel cell system stack remain unchanged, preventing the stack performance from degrading.

[0031] In addition, the real-time pressure at the fuel cell cathode inlet can be compared with the target set pressure at the fuel cell cathode inlet, and the opening of the back pressure valve 2 can be adjusted according to the comparison result; this achieves decoupling of the pressure regulation function of the back pressure valve 2 and the anti-surge protection function of the air compressor 1 in the control logic. The back pressure valve 2 is dedicated to maintaining the performance of the fuel cell stack, while the vent valve 4 is dedicated to ensuring the stable operation of the air compressor 1. Through the coordinated scheduling of the controller 5, the two jointly solve the contradiction between maintaining the high performance of the fuel cell stack and avoiding the surge of the air compressor in high-altitude environments.

[0032] In some preferred embodiments, the inlet air path also includes an air filter 6 and an air compressor inlet temperature, pressure and flow sensor 7 located upstream of the air compressor 1, and an intercooler 8, a humidifier 9, an inlet shut-off valve 10, and an air inlet temperature and pressure sensor 11 located downstream of the air compressor 1. The drain pipe is connected to the pipeline between the outlet of air compressor 1 and humidifier 9.

[0033] The outlet gas path also includes an air outlet pressure sensor 12, an outlet shut-off valve 13, and a humidity control valve 14 connected in sequence. The outlet of the humidity control valve 14 is connected to a back pressure valve 2.

[0034] The above details the specific architecture of the air control device for fuel cells. The bypass pipe is located between the outlet of air compressor 1 and humidifier 9, allowing for flow bypass before the air enters the thermal management components. This avoids interference from the flow resistance of intercooler 8 / humidifier 9 on the bypass effect. The bypass air does not pass through the humidifier, preventing a decrease in humidity of the incoming air due to bypass and maintaining the stability of the fuel cell's chemical reactions.

[0035] The function of air filter 6 is to filter particulate impurities and adsorb impurity gases in the air; the function of air compressor inlet temperature, pressure and flow sensor 7 is to monitor the air temperature, pressure and flow rate at the air compressor 1 inlet; the function of air compressor 1 is to compress air to provide oxygen to the fuel cell stack, and to control the air flow rate and pressure entering the fuel cell stack in conjunction with back pressure valve 2; the function of intercooler 8 is to cool the compressed air; humidifier 9 is a device that humidifies the dry air coming out of the supply section through the humidified air at the fuel cell stack outlet, and to control the flow rate of the humidified air entering the humidifier in conjunction with humidity regulating valve 14, thereby achieving the regulation of the humidity of the air entering the fuel cell stack; the function of inlet shut-off valve 10 and outlet shut-off valve 13 is to isolate the fuel cell stack from the atmosphere; the function of air inlet temperature and pressure sensor 11 is to monitor the temperature and pressure of the air entering the fuel cell stack; the function of air outlet pressure sensor 12 is to monitor the air outlet pressure; the function of relief valve 4 is to bypass a portion of the air flow in high-altitude environments to prevent air compressor surge or fuel cell stack cathode undergassing.

[0036] The specific function of back pressure valve 2 is as follows: Back pressure valve 2 is a key actuator whose core function is to establish and maintain the air pressure required on the cathode side of the fuel cell stack.

[0037] Specifically, its functions are reflected in the following aspects: Maintaining the cathode inlet pressure of the fuel cell stack is crucial, as the electrochemical reaction efficiency is directly related to the pressure of the reactant gases. A back pressure valve generates a back pressure within the cathode chamber by limiting the exhaust back pressure in the stack outlet gas path.

[0038] The controller can precisely control this pressure by adjusting the opening of the back pressure valve, stabilizing it at the optimal value set by the system, thereby ensuring the performance and output power of the fuel cell stack.

[0039] Working in conjunction with the air compressor to regulate the flow and pressure of air entering the reactor stack, the air supply system is a coupled system: the air compressor acts as a pump, responsible for providing gas and energy; the back pressure valve acts as a gate, responsible for establishing downstream pressure. The controller coordinates the control of the air compressor speed (which determines the air supply volume and outlet pressure) and the opening of the back pressure valve (which determines the outlet back pressure) to ensure that the air flow and pressure entering the reactor stack simultaneously meet the set requirements.

[0040] The particular importance of this system in high-altitude environments, where atmospheric pressure is low, necessitates a higher pressure ratio (outlet pressure / inlet pressure) to maintain the same absolute pressure inside the fuel cell stack as at lower altitudes. This requires the back pressure valve to close more tightly to create higher exhaust resistance, thereby helping the air compressor, along with the fuel cell stack cathode, establish the required high pressure at a lower inlet ambient pressure.

[0041] Secondly, an air control method for a fuel cell is provided, referencing... Figure 4 It includes: Provide the above-mentioned air control device for fuel cells; Step 100: Obtain the inlet flow rate of the target air compressor and the real-time air compressor pressure ratio; Step 200: Based on the surge protection curve in the air compressor flow rate and speed map, determine the surge risk critical pressure ratio according to the target air compressor inlet reduced flow rate; the surge protection curve can be referenced. Figure 2 ; Step 300: Use controller 5 to compare the real-time air compressor pressure ratio with the critical pressure ratio for surge risk, and then control the opening of the relief valve 4 and the speed of air compressor 1 according to the comparison result to regulate the air compressor pressure ratio. At the same time, compare the real-time pressure at the cathode inlet of the fuel cell stack with the target set pressure at the cathode inlet of the fuel cell stack, and adjust the opening of the back pressure valve 2 according to the comparison result.

[0042] The above achieves the coordinated control of bypassing the bleed valve 4 and increasing the speed of the air compressor 1, so that the air flow and pressure entering the fuel cell stack can be maintained at the set value in the high-altitude and low-pressure environment, avoiding the performance degradation caused by reducing the stack pressure in traditional solutions.

[0043] In addition, by utilizing the target air compressor inlet converted flow rate and the real-time air compressor pressure ratio, and then using the surge protection line of the air compressor map, surge risks can be identified and intervened in advance, thus preventing surge from occurring at its source.

[0044] When controller 5 detects that the system is in a high-altitude, low-pressure environment, it executes the following cooperative control strategy: The back pressure valve's primary pressure regulation: Controller 5 compares the real-time pressure feedback from the air inlet temperature and pressure sensor 11 with the target set pressure at the stack cathode inlet, generating a first control command. This first control command drives the back pressure valve 2 to adjust its opening—specifically, to compensate for the pressure drop in the high-altitude environment, controller 5 controls the back pressure valve 2 to decrease its opening, thereby increasing the exhaust back pressure in the outlet gas path and ensuring that the stack cathode inlet pressure remains stable at the set value. During this process, the control of the back pressure valve 2 prioritizes the performance requirements of the stack, and does not actively command it to open wider to reduce the system pressure ratio due to the potential surge risk of the air compressor 1.

[0045] Synergistic anti-surge mechanism of the relief valve and air compressor: Controller 5, in parallel, compares the acquired target inlet flow rate and real-time pressure ratio of the air compressor with the surge protection curve in the air compressor flow rate and speed map. When it is determined that the real-time pressure ratio is higher than the critical surge risk pressure ratio, a second control command is generated. This second control command is independent of the aforementioned control of the back pressure valve 2, and is used to drive the relief valve 4 to open to the target opening degree to release air flow, and simultaneously increase the speed of the air compressor 1 to compensate for the flow loss caused by the relief.

[0046] Through the above method, the pressure regulation function of the back pressure valve 2 and the anti-surge protection function of the air compressor 1 are decoupled in the control logic. The back pressure valve 2 is dedicated to maintaining the performance of the fuel cell stack, while the vent valve 4 is dedicated to ensuring the stable operation of the air compressor 1. Through the coordinated scheduling of the controller 5, the two jointly resolve the contradiction between maintaining the high performance of the fuel cell stack and avoiding the surge of the air compressor in high-altitude environments.

[0047] In some preferred embodiments, the mechanism of active surge prevention is described in detail below.

[0048] Step 300 specifically includes: When the real-time air compressor pressure ratio is greater than the critical pressure ratio for surge risk, the controller 5 controls the relief valve 4 to open to the target opening degree, and at the same time controls the air compressor 1 to increase its speed.

[0049] When the real-time air compressor pressure ratio is less than the critical pressure ratio for surge risk, the controller 5 controls the relief valve 4 to close, and the air compressor 1 maintains its original speed. That is, when the real-time air compressor pressure ratio is less than the critical pressure ratio for surge risk, the controller 5 controls the relief valve 4 to remain closed, and the real-time air compressor inlet flow rate and relief flow rate are added together to obtain the target air compressor inlet flow rate; based on the air compressor flow rate versus speed map, the target speed corresponding to the target air compressor inlet flow rate is obtained, and then the controller 5 controls the air compressor 1 to operate at the target speed.

[0050] In the air compressor's map diagram, when the flow rate is constant, an excessively high air compressor pressure ratio poses a surge risk. Therefore, the above control logic is implemented: Based on the setpoints for the air flow rate and pressure maintenance at the fuel cell inlet, the corresponding target air compressor inlet flow rate is calculated. Then, the surge risk critical pressure ratio corresponding to this target air compressor inlet flow rate is mapped. Finally, based on this surge risk critical pressure ratio, the vent valve 4 is opened to adjust the real-time air compressor pressure ratio. (See reference...) Figure 3 The diagram shows the operation of air compressor 1 at different altitudes (with the drain valve open at 3000m).

[0051] The specific control of the rotational speed is as follows: a. Obtain the discharge flow rate of the relief valve 4; This step specifically involves obtaining the discharge flow rate of the relief valve 4, including the following steps: using the air compressor inlet temperature, pressure and flow sensor 7 to obtain the real-time air compressor inlet flow rate, and then calculating the discharge flow rate by combining it with the calibrated discharge coefficient; The discharge coefficient is pre-stored in the controller 5; b. Add the real-time air compressor inlet flow and the discharge flow to obtain the target air compressor inlet flow; based on the air compressor flow and speed map, obtain the real-time speed corresponding to the real-time air compressor inlet flow and the target speed corresponding to the target air compressor inlet flow. c. Adjust the air compressor 1 from the real-time speed to the target speed.

[0052] The above should be understood as follows: When the bleed valve 4 is opened, the loss of feed flow needs to be compensated by increasing the speed. The loss of feed flow to be compensated is determined by the bleed flow, so the bleed flow needs to be calculated. That is, in order to ensure that the air flow into the fuel cell remains unchanged, the air compressor inlet flow needs to be increased. The amount of increase is the loss of bleed flow, which is the target air compressor inlet flow. Then, the target speed corresponding to the target air compressor inlet flow is obtained according to the air compressor flow and speed map, and then the target speed is adjusted as the target speed.

[0053] The above-mentioned device for measuring discharge flow does not have a dedicated flow sensor. Therefore, by utilizing the experimentally calibrated discharge coefficient δ, the flow sensor in the discharge pipeline is eliminated, reducing system complexity and hardware costs. The discharge flow is directly calculated based on the air compressor inlet flow, avoiding sensor signal delay and improving the real-time performance of the discharge action. Alternatively, a discharge flow sensor could be installed on the discharge pipeline to obtain the discharge flow of discharge valve 4; this is an alternative solution.

[0054] In the initial stage, the discharge flow rate of the relief valve 4 can be obtained by installing a flow sensor in the air pipeline where the relief valve 4 is located, and the discharge flow rate f of the relief valve at different opening degrees can be obtained. Bypass Calculate the discharge coefficient δ = f Bypass / f AcpIn After experimental testing and engineering calibration of δ, the flow sensor can be eliminated.

[0055] In some preferred embodiments, step 100 specifically includes: Obtaining the target air compressor inlet converted flow rate and the real-time air compressor pressure ratio specifically includes the following steps: Step 1001: Obtain the real-time ambient temperature T ref Environmental pressure P ref The air compressor inlet temperature T of air compressor 1 AcpIn and air compressor inlet pressure P AcpInAnd the real-time pressure P of the fuel cell stack StkIn ; Step 1002: Based on the set value f corresponding to the air flow rate entering the fuel cell stack. StkIn The target inlet flow rate of the air compressor, i.e., the target f, is calculated using Formula 1. AcpIn Formula 1 is f StkIn ≈90%f AcpIn .

[0056] In this step, the air compressor inlet pressure P AcpIn If we disregard the air filter flow resistance and approximate it as ambient pressure (ambient pressure equals the air filter flow resistance + air compressor inlet pressure), and considering that the air compressor's air bearing flow loss is approximately 8%–11%, the air inlet flow rate f... StkIn ≈90%f AcpIn ; Step 1003: Utilize the real-time ambient temperature T ref Environmental pressure P ref The air compressor inlet temperature T of air compressor 1 AcpIn and air compressor inlet pressure P AcpIn Based on the target inlet flow rate of the air compressor and calculation formula two, the equivalent inlet flow rate f of the air compressor is calculated. cr ; The formula for equivalent flow rate (Formula 2) is: f cr =f AcpIn *(P ref / P AcpIn )*sqrt((T AcpIn +273.15) / T ref +273.15); Among them, P ref =101.3 kPa, T ref =25℃.

[0057] Step 1004: Based on Formula 3, and combined with the real-time pressure P of the fuel cell stack... StkIn Calculate the real-time air compressor outlet pressure P AcpOut Formula 3 is P AcpOut =P StkIn +ΔP; ΔP is the pressure loss from the air outlet pressure through the intercooler, humidifier, and air piping to the air inlet. ΔP can be obtained through experimental testing and engineering calibration. Experimental calibration of ΔP resolves pressure estimation errors caused by flow resistance in piping / intercooler / humidifier, ensuring the reliability of surge detection. ΔP is calibrated as a fixed parameter and pre-stored in the controller to avoid complex online calculations and meet the real-time requirements of the vehicle controller. Step 1005: Based on Formula 4, and combined with the real-time air compressor outlet pressure PAcpOut and real-time air compressor inlet pressure P AcpIn Calculate the real-time air compressor pressure ratio Pr. Formula 4 is Pr = P AcpOut / P AcpIn .

[0058] The basic process described above is as follows: Identify the risk of air compressor surge in advance based on the air compressor's surge protection line; and determine the set value f corresponding to the air flow rate entering the fuel cell stack. StkIn Calculate the target inlet flow rate of the air compressor, i.e., the target f. AcpIn Calculate the target inlet flow rate f of the air compressor according to Formula 2. cr Based on the target inlet flow rate f of the air compressor cr In the air compressor map, the surge protection line is used to determine the critical pressure ratio for air compressor surge risk. If the actual air compressor pressure ratio is higher than this critical value, the air compressor is identified as having a surge risk, and the relief valve 4 is opened and the air compressor speed is increased.

[0059] In some preferred embodiments, the real-time pressure at the cathode inlet of the fuel cell stack is compared with the target set pressure at the cathode inlet of the fuel cell stack, and the opening of the back pressure valve 2 is adjusted according to the comparison result. Specifically, this includes the following steps: The real-time pressure at the cathode inlet of the fuel cell stack is obtained using the air inlet temperature and pressure sensor 11. Compare the real-time pressure at the cathode inlet of the fuel cell stack with the target set pressure at the cathode inlet of the fuel cell stack. If the real-time pressure at the cathode inlet of the fuel cell stack is less than the target set pressure at the cathode inlet of the fuel cell stack, the opening of the back pressure valve 2 is reduced based on the difference between the real-time pressure at the cathode inlet of the fuel cell stack and the target set pressure at the cathode inlet of the fuel cell stack. If the real-time pressure at the cathode inlet of the fuel cell stack is greater than the target set pressure at the cathode inlet of the fuel cell stack, the opening of the back pressure valve 2 will be increased based on the difference between the real-time pressure at the cathode inlet of the fuel cell stack and the target set pressure at the cathode inlet of the fuel cell stack.

[0060] First, this closed-loop feedback and control mechanism establishes a dynamic fine-tuning capability for the reactor stack cathode inlet pressure. By utilizing the air inlet temperature and pressure sensor 11 to directly acquire the most accurate reactor stack inlet state and rapidly and continuously compare it with the target setpoint, a precise closed-loop control circuit is formed. This control strategy, which directly targets the key parameters of the reactor stack inlet, fundamentally ensures the stability of the core parameter of the reactor stack reaction environment—pressure—laying a solid foundation for maintaining the high-performance output of the reactor stack.

[0061] Secondly, the deterministic control logic of the back pressure valve in high-altitude environments was clarified. Specifically, when the real-time pressure is low, the back pressure valve is instructed to close slightly to increase the pressure; when the real-time pressure is high, the back pressure valve is instructed to open wider to release the pressure. This logic ensures that under any operating condition, the control command of the back pressure valve steadfastly prioritizes maintaining the optimal operating condition of the fuel cell stack. This aligns perfectly with the core principle of prioritizing fuel cell stack performance, preventing the back pressure valve from compromising fuel cell stack performance due to the risk of compressor surge.

[0062] Ultimately, this precise pressure control and the aforementioned anti-surge venting control achieve perfect functional decoupling and strategic synergy. Each performs its specific function, while the controller coordinates them uniformly, jointly achieving the previously contradictory goals of maintaining stack performance and preventing compressor surge in high-altitude, low-pressure environments. This significantly enhances the environmental adaptability and operational reliability of the fuel cell system.

[0063] In some preferred embodiments, the air control method for the fuel cell further includes step 400.

[0064] Step 400 specifically includes the following steps: Obtain the real-time converted flow rate at the air compressor inlet; Based on the surge curve in the air compressor flow and speed map, the critical pressure ratio for surge fault is determined according to the real-time reduced flow rate at the air compressor inlet. The controller 5 is used to compare the real-time air compressor pressure ratio with the critical pressure ratio for surge fault; When the real-time air compressor pressure ratio is greater than the critical pressure ratio for surge fault, the controller 5 controls the relief valve 4 to open to the target opening degree, and at the same time shuts down the air compressor 1.

[0065] The calculation method for the real-time equivalent flow rate at the air compressor inlet is the same as that for the target equivalent flow rate at the air compressor inlet.

[0066] By calculating the critical surge fault pressure ratio corresponding to the real-time converted flow rate at the air compressor inlet, the real-time air compressor pressure ratio can be compared with the critical surge fault pressure ratio to determine whether a fault has occurred. If the surge fault threshold is exceeded, the vent valve 4 is immediately opened, shutting off the air compressor to prevent physical damage to the compressor blades caused by surge. This, together with the prevention mechanism, forms a "warning-fuse" dual-level protection, covering the entire process from risk budding to fault outbreak, thus improving system safety.

[0067] Furthermore, the above air compressor flow rate and speed map includes surge protection curves at different altitudes; Obtaining the surge protection curve from the air compressor flow rate and speed Map diagram includes the following steps: The altitude of the current location of air compressor 1 is obtained, and then the corresponding surge protection curve is determined based on the altitude. This enables precise control of the speed of air compressor 1 and the operation of the relief valve 4 at different altitudes.

[0068] Thirdly, embodiments of this application provide an air control device for a fuel cell system. The air control device for the fuel cell system can be a personal computer (PC), a laptop computer, a server, an on-board chip, a vehicle ECU, or other devices with data processing capabilities.

[0069] In this embodiment, the air control device of the fuel cell system may include a processor, a memory, a communication interface, and a communication bus.

[0070] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0071] The communication interface includes input / output (I / O) interfaces, physical interfaces, and logical interfaces used for interconnecting components within the air control equipment of the fuel cell system, as well as interfaces used for interconnecting the air control equipment of the fuel cell system with other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0072] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0073] The processor can be a general-purpose processor, which can call the air control program of the fuel cell system stored in the memory and execute the air control method of the fuel cell system provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the air control program of the fuel cell system is called can be referred to in the various embodiments of the air control method of the fuel cell system of this application, and will not be repeated here.

[0074] Fourthly, embodiments of this application also provide a computer-readable storage medium.

[0075] The present application provides a computer-readable storage medium storing an air control program for a fuel cell system, wherein when the air control program for the fuel cell system is executed by a processor, it implements the steps of the air control method for the fuel cell system as described above.

[0076] The method implemented when the air control program of the fuel cell system is executed can be referred to in various embodiments of the air control method of the fuel cell system of this application, and will not be repeated here.

[0077] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0078] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0079] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A fuel cell system, characterized in that, It includes: The inlet gas path includes an air compressor (1); The outlet gas path includes a back pressure valve (2); An exhaust pipe (3) is connected to the back pressure valve (2) for exhausting gas to the outside atmosphere; A relief valve (4) is connected to the exhaust pipe (3) via a relief pipe connected to the outlet of the air compressor (1); The controller (5) is connected to the air compressor (1), back pressure valve (2) and drain valve (4) by signal. The controller (5) is used to control the opening degree of the drain valve (4) and the speed of the air compressor (1) to regulate the air compressor pressure ratio of the air compressor (1). The controller (5) is also used to control the opening degree of the back pressure valve (2) to adjust the exhaust back pressure of the reactor gas path.

2. The fuel cell system as described in claim 1, characterized in that: The inlet air path also includes an air filter (6) and an air compressor inlet temperature, pressure and flow sensor (7) located upstream of the air compressor (1), as well as an intercooler (8), a humidifier (9), an inlet shut-off valve (10), and an air inlet temperature and pressure sensor (11) located downstream of the air compressor (1). The drain pipe is connected to the pipeline between the outlet of the air compressor (1) and the humidifier (9).

3. The fuel cell system as described in claim 1, characterized in that: The outlet gas path also includes an air outlet pressure sensor (12), an outlet shut-off valve (13), and a humidity control valve (14) connected in sequence, with the outlet of the humidity control valve (14) connected to the back pressure valve (2).

4. An air control method for a fuel cell system as described in claim 1, characterized in that, It includes: Obtain the converted flow rate at the inlet of the target air compressor, as well as the real-time air compressor pressure ratio; Based on the surge protection curve in the Map diagram of air compressor flow rate and speed, and combined with the reduced flow rate at the inlet of the target air compressor, the critical pressure ratio for surge risk is determined. The real-time air compressor pressure ratio is compared with the critical pressure ratio for surge risk. Then, the opening of the relief valve (4) and the speed of the air compressor (1) are controlled according to the comparison results to regulate the air compressor pressure ratio. At the same time, the real-time pressure at the cathode inlet of the fuel cell stack is compared with the target set pressure at the cathode inlet of the fuel cell stack. The opening of the back pressure valve (2) is adjusted according to the comparison results.

5. The air control method for a fuel cell system as described in claim 4, characterized in that: When the real-time air compressor pressure ratio is greater than the critical pressure ratio for surge risk, the controller (5) controls the vent valve (4) to open to the target opening degree, and at the same time controls the air compressor (1) to increase its speed.

6. The air control method for a fuel cell system as described in claim 5, characterized in that, Controlling the air compressor (1) to increase its speed includes the following steps: Obtain the discharge flow rate of the relief valve (4); The target air compressor inlet flow rate is obtained by adding the real-time air compressor inlet flow rate and the outlet flow rate. Based on the Map diagram of air compressor flow rate and speed, the real-time speed corresponding to the real-time air compressor inlet flow rate and the target speed corresponding to the target air compressor inlet flow rate are obtained. Control the air compressor (1) to adjust from the real-time speed to the target speed.

7. The air control method for a fuel cell system as described in claim 6, characterized in that: The fuel cell system's inlet gas path also includes an air filter (6) and an air compressor inlet temperature, pressure and flow sensor (7) located upstream of the air compressor (1), and an intercooler (8), a humidifier (9), an inlet shut-off valve (10), and an air inlet temperature and pressure sensor (11) located downstream of the air compressor (1); the vent pipe is connected to the pipeline between the air compressor (1) outlet and the humidifier (9); Obtaining the discharge flow rate of the relief valve (4) specifically includes the following steps: The real-time air compressor inlet flow rate is obtained using the air compressor inlet temperature, pressure and flow sensor (7), and then the discharge flow rate is calculated by combining the calibrated discharge coefficient; the discharge coefficient is pre-stored in the controller (5).

8. The air control method for a fuel cell system as described in claim 6, characterized in that: The fuel cell system's inlet gas path also includes an air filter (6) and an air compressor inlet temperature, pressure and flow sensor (7) located upstream of the air compressor (1), and an intercooler (8), a humidifier (9), an inlet shut-off valve (10), and an air inlet temperature and pressure sensor (11) located downstream of the air compressor (1); the vent pipe is connected to the pipeline between the air compressor (1) outlet and the humidifier (9); a vent flow sensor is provided on the vent pipe; The discharge flow rate of the discharge valve (4) is obtained using the discharge flow sensor.

9. The air control method for a fuel cell system as described in claim 4, characterized in that: When the real-time air compressor pressure ratio is less than the critical pressure ratio for surge risk, the controller (5) controls the vent valve (4) to remain closed, and adds the real-time air compressor inlet flow and vent flow to obtain the target air compressor inlet flow; based on the Map diagram of air compressor flow and speed, the target speed corresponding to the target air compressor inlet flow is obtained, and then the controller (5) controls the air compressor (1) to run at the target speed.

10. The air control method for a fuel cell system as described in claim 4, characterized in that, Obtaining the target air compressor inlet converted flow rate and the real-time air compressor pressure ratio specifically includes the following steps: The real-time ambient temperature, ambient pressure, air compressor inlet temperature and air compressor inlet pressure of air compressor (1), and real-time pressure of fuel cell stack are obtained. The target inlet flow rate of the air compressor is calculated based on the set value corresponding to the air flow rate of the fuel cell stack; the target inlet flow rate of the air compressor is calculated by using the real-time ambient temperature, ambient pressure, air compressor inlet temperature and air compressor inlet pressure of the air compressor (1), and the target inlet flow rate of the air compressor, combined with the reduced flow rate formula. Based on the real-time pressure of the fuel cell stack and the calibrated pressure loss, the real-time air compressor outlet pressure is calculated; then, based on the real-time air compressor outlet pressure and air compressor inlet pressure, the real-time air compressor pressure ratio is calculated.

11. The air control method for a fuel cell system as described in claim 7, characterized in that, The real-time pressure at the cathode inlet of the fuel cell stack is compared with the target set pressure at the cathode inlet of the fuel cell stack, and the opening of the back pressure valve (2) is adjusted according to the comparison result. Specifically, the following steps are included: The real-time pressure at the cathode inlet of the fuel cell stack is obtained using an air inlet temperature and pressure sensor (11). Compare the real-time pressure at the cathode inlet of the fuel cell stack with the target set pressure at the cathode inlet of the fuel cell stack. If the real-time pressure at the cathode inlet of the fuel cell stack is less than the target set pressure at the cathode inlet of the fuel cell stack, then the opening of the back pressure valve (2) is reduced based on the difference between the real-time pressure at the cathode inlet of the fuel cell stack and the target set pressure at the cathode inlet of the fuel cell stack. If the real-time pressure at the cathode inlet of the fuel cell stack is greater than the target set pressure at the cathode inlet of the fuel cell stack, the opening of the back pressure valve (2) is increased based on the difference between the real-time pressure at the cathode inlet of the fuel cell stack and the target set pressure at the cathode inlet of the fuel cell stack.

12. The air control method for a fuel cell system as described in claim 4, characterized in that, It also includes the following steps: Obtain the real-time converted flow rate at the air compressor inlet; Based on the surge curve in the air compressor flow and speed map, the critical pressure ratio for surge fault is determined according to the real-time reduced flow rate at the air compressor inlet. The real-time air compressor pressure ratio is compared with the critical pressure ratio of surge fault using the controller (5); When the real-time air compressor pressure ratio is greater than the critical pressure ratio of surge fault, the controller (5) controls the vent valve (4) to open to the target opening degree, and at the same time shuts down the air compressor (1).

13. The air control method for a fuel cell system as described in claim 4, characterized in that: The air compressor flow rate and speed map includes surge protection curves at different altitudes; Obtaining the surge protection curve from the air compressor flow rate and speed Map diagram specifically includes the following steps: Obtain the altitude of the current location of the air compressor (1), and then determine the corresponding surge protection curve based on the altitude.

14. An air control device for a fuel cell system, characterized in that, The air control device of the fuel cell system includes a processor, a memory, and an air control program of the fuel cell system stored in the memory and executable by the processor, wherein when the air control program of the fuel cell system is executed by the processor, it implements the steps of the air control method of the fuel cell system as described in any one of claims 4 to 13.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores an air control program for a fuel cell system, wherein when the air control program for the fuel cell system is executed by a processor, it implements the steps of the air control method for the fuel cell system as described in any one of claims 4 to 13.

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