Hydrogen gas path system and hydrogen pressure control method suitable for high-power hydrogen fuel cell stack

Abstract

The present invention proposes a hydrogen circuit system and a hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack, and relates to the field of fuel cell technology. The hydrogen circuit design of the double proportional valve + double ejector in the present invention can not only meet the requirements of the hydrogen flow and hydrogen pressure of the high-power hydrogen fuel cell system, but also can meet the precise control of the hydrogen inlet pressure at all electrical density points. The design of the three-way valve is introduced, so that the hydrogen pressure control of the high-power hydrogen fuel cell system can be precisely controlled from the small electrical density point to the large electrical density point. The calibration method proposed by the present invention, when the system is turned on, both proportional valves will work, avoiding the hydrogen pressure fluctuation problem caused by the second proportional valve being opened again when the first proportional valve is opened to the maximum; the control method mainly utilizes the characteristics that the proportional valve can better control the hydrogen pressure at the small electrical density point, and the ejector is more suitable for controlling the hydrogen inlet pressure at the large electrical density point, and is more suitable for the hydrogen pressure control of the high-power hydrogen fuel cell system at all electrical density points.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a hydrogen gas path system and a hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack. Background Art

[0002] In recent years, hydrogen fuel cell systems are most widely used in heavy-duty truck models. Compared with traditional fuel trucks, hydrogen fuel cell systems have less pollution and higher power generation efficiency; compared with electric trucks, they have longer endurance and are suitable for long-distance transportation, and have a wider range of application scenarios, so it is necessary to develop high-power fuel cell systems to meet the power needs of heavy-duty trucks. The demand for hydrogen consumption in high-power fuel cell systems has increased. The existing technology proposes to increase the hydrogen flow rate by increasing the diameter of the proportional valve, but the accuracy of the hydrogen inlet pressure control will decrease as the diameter increases; there are also existing technologies that design two proportional valves in parallel, or connect them in parallel with the hydrogen injector in series to increase the hydrogen inlet flow and pressure, but this design also depends on the size of the hydrogen injector nozzle. If the diameter of the hydrogen injector nozzle is too large, the hydrogen pressure control will be unstable. If it is too small, it may not be able to meet the hydrogen flow demand of the stack.

[0003] In addition, the patent CN117497808A-A fuel cell dual proportional valve system and control method proposes that the control method of the dual proportional valve is to adjust the low-electrical-density first proportional valve PID. When the first proportional valve is opened to the maximum opening, the maximum opening is maintained, and the second bypass proportional valve intervenes and is adjusted by PID. This control method has the following problems in actual experiments: when the second bypass proportional valve begins to intervene, most systems are in a medium-high electric-density operation state. At the beginning of the intervention, due to the delay characteristics of the proportional valve and the effective opening range and other characteristics, the hydrogen inlet pressure of the fuel cell system fluctuates greatly. If the set pressure is just at the full opening of the first proportional valve, the second proportional valve opening PID opening is adjusted at a very small value, which will have a great impact on the fluctuation of the hydrogen inlet pressure. Summary of the invention

[0004] In view of the above problems, the present invention proposes a hydrogen gas circuit system and a hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack. Through reasonable pipeline layout and applicable control methods, the hydrogen pressure control problem of the high-power fuel cell system is solved, and the accurate and stable control of the hydrogen pressure is achieved. Without changing the caliber of the proportional valve, not only can the hydrogen inlet pressure be accurately controlled, but also the cost of developing a new large-caliber proportional valve can be reduced.

[0005] To this end, the present invention adopts the following technical solutions:

[0006] The present invention discloses a hydrogen gas path system suitable for a high-power hydrogen fuel cell stack, comprising:

[0007] The hydrogen source is connected to the first proportional valve and the second proportional valve respectively through a high-pressure solenoid valve; the first proportional valve and the second proportional valve are connected in parallel;

[0008] The first proportional valve is connected to the first three-way valve, the rear end of the first three-way valve is connected in parallel to the first ejector and the fuel cell stack, and the first ejector is connected to the fuel cell stack; the first proportional valve, the first three-way valve and the first ejector or the fuel cell stack form a hydrogen supply path;

[0009] The second proportional valve is connected to the second three-way valve, the rear end of the second three-way valve is connected in parallel to the second ejector and the fuel cell stack, and the second ejector is connected to the fuel cell stack; the second proportional valve, the second three-way valve and the second ejector or the fuel cell stack form a second hydrogen supply path;

[0010] The reflux hydrogen is divided into three paths after passing through the gas-liquid separator. One path is connected to the hydrogen circulation pump and then enters the fuel cell stack, and the other two paths are connected in parallel to the first ejector and the second ejector respectively.

[0011] Furthermore, it also includes: a hydrogen inlet pressure sensor located at the front end of the fuel cell stack, which is used to monitor the hydrogen inlet pressure.

[0012] Furthermore, the first proportional valve and the second proportional valve have the same caliber.

[0013] Furthermore, the nozzle diameters of the first ejector and the second ejector are the same, and there is no need to customize an ejector with a larger diameter.

[0014] Furthermore, it also includes: a high-pressure sensor arranged on a pipeline connecting the hydrogen source and the high-pressure solenoid valve.

[0015] The present invention also provides a hydrogen pressure control method applicable to a high-power hydrogen fuel cell stack, characterized in that, based on the above-mentioned hydrogen path system, the hydrogen pressure control method comprises the following steps:

[0016] S1: Manually find the effective range of the proportional valve and determine the minimum and maximum opening of the proportional valve;

[0017] S2: Keep the first proportional valve to control the opening of the first proportional valve according to the PI adjustment method of the low-power system;

[0018] S3: The system is turned on, the second proportional valve is opened at the minimum opening, and the opening of the second proportional valve is calibrated according to the order of increasing electrical density points. The calibration process refers to the opening of the first proportional valve. The opening of the first proportional valve cannot be too large, and it cannot exceed the effective range at a large electrical density. The openings of the two proportional valves are controlled to be within the range of 20%-80% of the effective opening.

[0019] S4: Restart the system, the second proportional valve opens according to the calibrated opening, the first proportional valve performs fuzzy PI adjustment according to the difference between the hydrogen pressure setting value and the hydrogen pressure feedback value, and whether to use the first ejector and / or the second ejector is selected according to the electrical density setting.

[0020] Furthermore, manually find the effective range of the proportional valve and determine the minimum and maximum opening of the proportional valve, including:

[0021] S11, close the manual ball valve and record the pressure value P0 of the pressure sensor at this time;

[0022] S12, gradually increase the proportional valve opening until the pressure value of the pressure sensor changes, and record the proportional valve opening at this time, which is the minimum value Y0 of the effective proportional valve opening;

[0023] S13, opening the manual ball valve to a preset angle, and recording the pressure value P1 of the pressure sensor at this time;

[0024] S14, gradually increase the opening of the proportional valve until the pressure value of the pressure sensor no longer changes, and record the proportional valve opening at this time, which is the maximum effective opening Y1 of the proportional valve;

[0025] S15. Record the effective interval Y0-Y1 of the proportional valve.

[0026] Furthermore, the calibration of the second proportional valve includes:

[0027] S31, the system is turned on, and the minimum opening of the second proportional valve is set to Y0;

[0028] S32, small electric density pull load, set the hydrogen inlet pressure setting value, record the first proportional valve opening feedback value V1, then calibrate the opening of the second proportional valve to 0.5V1 + X0; the size of X0 refers to the first proportional valve opening feedback value, so that the calibrated second proportional valve opening is within the effective range of more than 20%;

[0029] S33, pull the load electric density in turn, calibrate the opening of the second proportional valve, when the electric density reaches the middle, the opening of the second proportional valve is 0.5V1 + 0;

[0030] S34, when the electric density reaches the maximum, the opening of the second proportional valve is calibrated to 0.5V1 - X1; the size of X1 refers to the feedback value of the opening of the first proportional valve, so that the calibrated opening of the second proportional valve is within the effective range of less than 80%;

[0031] S35. Record the opening of the calibrated second proportional valve to complete the calibration.

[0032] Further, selecting whether to use the first ejector and / or the second ejector according to the electric density setting includes:

[0033] Define small electric density, intermediate electric density and large electric density according to the hydrogen fuel cell system;

[0034] When the electric density is low, the first three-way valve opens the branch without ejector and closes the branch connected to the ejector. Similarly, the second three-way valve also opens the branch without ejector, and the double proportional valve is used to control the hydrogen inlet pressure.

[0035] When the intermediate electrical density is reached, the first three-way valve opens the branch connected to the ejector and closes the branch without the ejector. The second three-way valve opens the branch without the ejector, and the double proportional valve and the single ejector are used to control the hydrogen inlet pressure.

[0036] When the electric density is high, the first three-way valve opens the branch connected to the ejector and closes the branch without the ejector. The second three-way valve opens the branch connected to the ejector, and the double proportional valve and double ejectors are used to control the hydrogen inlet pressure.

[0037] Advantages and positive effects of the present invention:

[0038] The design of the double proportional valve + double ejector in the present invention can not only meet the requirements of hydrogen flow and hydrogen pressure of the high-power hydrogen fuel cell system, but also meet the precise control of hydrogen inlet pressure at all electrical density points. The design of the three-way valve is introduced to enable the hydrogen pressure control of the high-power hydrogen fuel cell system to be precisely controlled from the small electrical density point to the large electrical density point. In addition, the calibration method proposed in the present invention, when the system is turned on, both proportional valves will work, avoiding the hydrogen pressure fluctuation problem caused when the first proportional valve is opened to the maximum and the second proportional valve is opened again; and the calibration and control method mainly utilizes the characteristics that the proportional valve can better control the hydrogen pressure at the small electrical density point, and the ejector is more suitable for controlling the hydrogen inlet pressure at the large electrical density point, which is more suitable for the hydrogen pressure control of the high-power hydrogen fuel cell system at all electrical density points; the first proportional valve adopts the fuzzy PI control method, which will also make the relatively simple PI control of hydrogen pressure control more precise. This design principle and control method can meet the hydrogen pressure requirements of the high-power hydrogen fuel cell system at all electrical density points, and can also more accurately control the hydrogen inlet pressure, and improve the operation stability and durability of the high-power hydrogen fuel cell system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 This is a schematic diagram of a hydrogen gas path design suitable for a high-power hydrogen fuel cell system in an embodiment of the present invention;

[0041] Figure 2 Schematic diagram of manually calibrating the effective opening of a proportional valve in an embodiment of the present invention;

[0042] Figure 3 It is a schematic diagram of the dual proportional valve control strategy in an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of the first proportional valve control strategy in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0046] In order to solve the defects of the hydrogen circuit principle design of the existing high-power hydrogen fuel cell stack and the problem of large hydrogen pressure fluctuation when the second proportional valve is opened in the dual proportional valve control, the present invention proposes a hydrogen circuit principle design and a hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack, through a reasonable layout of dual proportional generators and dual ejectors and a control strategy of dual proportional valves, precise control of the hydrogen pressure at the full power point (full power point) of the high-power system is achieved.

[0047] A schematic diagram of a hydrogen gas path design suitable for a high-power hydrogen fuel cell stack in an embodiment of the present invention is shown in FIG. Figure 1As shown, the hydrogen source mixes fresh hydrogen with reflux hydrogen through a hydrogen supply valve group of dual proportional valves + dual ejectors, and then adjusts a relatively stable hydrogen inlet pressure to supply the fuel cell stack. The first proportional valve (proportional valve 1) is connected to the first three-way valve (three-way valve 1), and the rear end of the first three-way valve is connected in parallel to the first ejector (ejector 1) or the fuel cell stack. The first proportional valve, the first three-way valve and the first ejector or the fuel cell stack form a hydrogen supply path, which serves as the main hydrogen supply path; the second proportional valve (proportional valve 2) is connected to the second three-way valve (three-way valve 2), and the rear end of the second three-way valve is connected in parallel to the second ejector or the fuel cell stack. The second proportional valve, the second three-way valve and the second ejector or the fuel cell stack form a second hydrogen supply path, which serves as an auxiliary hydrogen supply path, i.e., a hydrogen supply bypass path; the first proportional valve and the second proportional valve are connected in parallel; the first proportional valve and the second proportional valve are connected in parallel. The calibers of the two proportional valves are the same, and there is no need to customize an ejector with a larger caliber, so as to avoid the reduction of the accuracy of hydrogen pressure regulation due to the increase of the caliber of the ejector; the nozzle calibers of the first ejector and the second ejector are the same; the function of the first three-way valve is to select whether the hydrogen entry method passes through the first ejector, and the function of the second three-way valve is to select whether the hydrogen entering the stack passes through the second ejector; the other ends of the first ejector and the second ejector are connected to the reflux hydrogen at the rear end of the gas-liquid separator. The first ejector and the second ejector can increase the hydrogen inflow and pressure at medium and high electrical density, and enable the fresh hydrogen and the reflux hydrogen to be fully mixed. The reflux hydrogen is divided into three paths after passing through the gas-liquid separator. One path is connected to the hydrogen circulation pump and then enters the stack, and the other two paths are connected in parallel to the first ejector and the second ejector. The hydrogen inflow pressure sensor is located at the front end of the stack to monitor the hydrogen inflow pressure.

[0048] In the above hydrogen circuit design, the design of adding a proportional valve and an ejector branch can meet the demand of high-power fuel cell systems, especially high-electrical density points, for hydrogen flow; without increasing the diameter of the proportional valve, the proportional valve can control the hydrogen pressure more accurately; the design of adding an ejector can meet the demand of high-power fuel cell systems, especially high-electrical density points, for hydrogen pressure, and the ejector can make the reflux hydrogen and fresh hydrogen fully mixed before entering the fuel cell stack, thereby improving the reaction efficiency of the fuel cell system; without increasing the diameter of the ejector, the control of hydrogen inlet pressure is also relatively more accurate; the design of the three-way valve allows the selective use of the ejector; the ejector has a poor ejection effect under low-electrical density conditions, so if the high-power fuel cell system is operating at a low-electrical density point, the ejector is not needed, and when operating at a high-electrical density point, the ejector has an obvious ejection effect, so the ejector can be used selectively to better control the hydrogen inlet pressure.

[0049] Based on the above hydrogen path design scheme, an embodiment of the present invention further proposes a hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack, comprising the following steps:

[0050] S1: Manually find the effective range of the proportional valve and determine the minimum and maximum opening of the proportional valve;

[0051] In specific implementation, Figure 2 As shown, you can follow the steps below:

[0052] S11, close the manual ball valve and record the pressure value P0 of the pressure sensor at this time;

[0053] S12, gradually increase the proportional valve opening until the pressure value of the pressure sensor changes (increases), and record the proportional valve opening at this time, which is the minimum value Y0 of the effective proportional valve opening;

[0054] S13, open the manual ball valve by a small angle and record the pressure value P1 of the pressure sensor at this time;

[0055] S14, continue to gradually increase the opening of the proportional valve until the pressure value of the pressure sensor no longer changes (increases), and record the proportional valve opening at this time, which is the maximum effective opening of the proportional valve Y1;

[0056] S15. Record the effective interval Y0-Y1 of the proportional valve.

[0057] S2: Keep the first proportional valve to control the opening of the first proportional valve according to the PI adjustment method of the low-power system;

[0058] S3: The system is turned on, the second proportional valve is opened at the minimum opening, and calibration begins;

[0059] First, keep the first proportional valve in the PI adjustment mode of the low-power system to control the opening of the first proportional valve, and manually calibrate the proportional valve 2. Calibration principle: calibrate the opening of the second proportional valve in the order of increasing electrical density points. The calibration process refers to the opening of the first proportional valve. The opening of the first proportional valve cannot be too large, and it cannot exceed the effective range at high electrical density. Try to control the opening of the two proportional valves within the effective opening range of 20%-80%.

[0060] In the specific implementation, the calibration is carried out according to the following steps:

[0061] S31, the system is turned on, and the minimum opening of the second proportional valve is set to Y0;

[0062] S32, small electric density pull load, set the hydrogen inlet pressure setting value, record the first proportional valve opening feedback value V1, and calibrate the opening of the second proportional valve to (0.5V1 + X0); the size of X0 refers to the first proportional valve opening feedback value, and try to make the calibrated second proportional valve opening greater than 20% of the effective range (the first few low electric densities can be greater than 10%);

[0063] S33, according to the system calibration MAP (calibration curve), pull the load density in turn, calibrate the opening of the second proportional valve, when the middle density is reached, the opening of the second proportional valve is (0.5V1 + 0);

[0064] S34, when the electric density reaches the maximum, the opening of the second proportional valve is (0.5V1 – X1); the size of X1 refers to the feedback value of the opening of the first proportional valve, and the opening of the calibrated second proportional valve is within the effective range of less than 80% as much as possible;

[0065] S35. The calibrated opening of the second proportional valve is written into MAP, and the calibration is completed.

[0066] S4: Restart the system, the second proportional valve opens according to the calibrated opening, the first proportional valve performs fuzzy PI adjustment according to the difference between the hydrogen pressure setting value and the hydrogen pressure feedback value, and whether to use the ejector is selected according to the electrical density setting.

[0067] The control strategy of the dual proportional valve is as follows Figure 3 As shown, the control mode of the first proportional valve is fuzzy PI regulation, specifically, fuzzy calculation is performed according to the difference (△e(t)) between the hydrogen pressure set value and the hydrogen pressure feedback value to obtain the P and I regulation parameters △Kp and △Ki of the PI controller, as shown in Figure 4 In fuzzy PI regulation, the membership function is a triangular membership function; the centroid method is used to resolve the fuzzy output; the fuzzy rules are shown in Table 1 and Table 2.

[0068] Table 1

[0069]

[0070] Table 2

[0071]

[0072] Among them, whether to use the ejector is selected according to the electrical density setting, including:

[0073] According to the hydrogen fuel cell system, the small current density, intermediate current density and large current density are defined; in the embodiment of the present invention, the small current density is defined as 0-700mA / cm 2 , the intermediate electrical density is defined as 800-1000mA / cm 2 , the maximum current density is defined as 1100-2000mA / cm 2 ; It is not limited to this division and needs to be redefined with reference to the characteristics of each system during calibration.

[0074] When the electric density is low, the first three-way valve opens the branch without ejector and closes the branch connected to the ejector. Similarly, the second three-way valve also opens the branch without ejector, and the double proportional valve is used to control the hydrogen inlet pressure.

[0075] When the intermediate electrical density is reached, the first three-way valve opens the branch connected to the ejector and closes the branch without the ejector. The second three-way valve opens the branch without the ejector, and the double proportional valve and the single ejector are used to control the hydrogen inlet pressure.

[0076] When the electric density is high, the first three-way valve opens the branch connected to the ejector and closes the branch without the ejector. The second three-way valve opens the branch connected to the ejector, and the double proportional valve and double ejectors are used to control the hydrogen inlet pressure.

[0077] In the proportional valve calibration method in the above embodiment, when the system is turned on, both proportional valves will work, avoiding the hydrogen pressure fluctuation problem caused when the first proportional valve is opened to the maximum and the second proportional valve is opened again; and the calibration and control method mainly utilizes the characteristics that the proportional valve can better control the hydrogen pressure at the small electrical density point, while the ejector is more suitable for controlling the hydrogen inlet pressure at the large electrical density point, and is more suitable for the hydrogen pressure control of the full electrical density point of the high-power hydrogen fuel cell system; the first proportional valve adopts the fuzzy PI control method, which will also make the relatively simple PI control of hydrogen pressure control more accurate. This design principle and control method can meet the hydrogen pressure requirements of the full electrical density point of the high-power hydrogen fuel cell system, and can also more accurately control the hydrogen inlet pressure, improving the operating stability and durability of the high-power hydrogen fuel cell system.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack, It is characterized in that The hydrogen gas path system suitable for a high-power hydrogen fuel cell stack comprises: The hydrogen source is connected to the first proportional valve and the second proportional valve respectively through a high-pressure solenoid valve; the first proportional valve and the second proportional valve are connected in parallel; The first proportional valve is connected to the first three-way valve, the rear end of the first three-way valve is connected in parallel to the first ejector and the fuel cell stack, and the first ejector is connected to the fuel cell stack; the first proportional valve, the first three-way valve and the first ejector or the fuel cell stack constitute a first hydrogen supply path; The second proportional valve is connected to the second three-way valve, the rear end of the second three-way valve is connected in parallel to the second ejector and the fuel cell stack, and the second ejector is connected to the fuel cell stack; the second proportional valve, the second three-way valve and the second ejector or the fuel cell stack form a second hydrogen supply path; The reflux hydrogen is divided into three paths after passing through the gas-liquid separator. One path is connected to the hydrogen circulation pump and then enters the fuel cell stack, and the other two paths are connected in parallel to the first ejector and the second ejector respectively. Wherein, the first proportional valve and the second proportional valve have the same caliber; The nozzle diameters of the first ejector and the second ejector are the same, and there is no need to customize an ejector with a larger diameter; The hydrogen pressure control method comprises the following steps: S1: Manually find the effective range of the proportional valve and determine the minimum and maximum opening of the proportional valve; S2: Keep the first proportional valve to control the opening of the first proportional valve according to the PI adjustment method of the low-power system; S3: The system is turned on, the second proportional valve is opened at the minimum opening, and the opening of the second proportional valve is calibrated according to the order of increasing electrical density points. The calibration process refers to the opening of the first proportional valve. The opening of the first proportional valve cannot be too large, and it cannot exceed the effective range at a large electrical density. The openings of the two proportional valves are controlled to be within the range of 20%-80% of the effective opening. S4: Restart the system, the second proportional valve opens according to the calibrated opening, the first proportional valve performs fuzzy PI adjustment according to the difference between the hydrogen pressure setting value and the hydrogen pressure feedback value, and whether to use the first ejector and / or the second ejector is selected according to the electrical density setting.

2. A hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack according to claim 1, It is characterized in that The hydrogen gas path system suitable for a high-power hydrogen fuel cell stack also includes: a hydrogen gas inlet pressure sensor located at the front end of the stack, which is used to monitor the hydrogen gas inlet pressure.

3. A hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack according to claim 1, It is characterized in that The hydrogen gas path system suitable for a high-power hydrogen fuel cell stack further includes: a high-pressure sensor arranged on a pipeline connecting a hydrogen gas source and a high-pressure solenoid valve.

4. A hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack according to claim 1, It is characterized in that Manually find the effective range of the proportional valve and determine the minimum and maximum opening of the proportional valve, including: S11, close the manual ball valve and record the pressure value P0 of the pressure sensor at this time; S12, gradually increase the proportional valve opening until the pressure value of the pressure sensor changes, and record the proportional valve opening at this time, which is the minimum value Y0 of the effective proportional valve opening; S13, opening the manual ball valve to a preset angle, and recording the pressure value P1 of the pressure sensor at this time; S14, gradually increase the opening of the proportional valve until the pressure value of the pressure sensor no longer changes, and record the proportional valve opening at this time, which is the maximum effective opening Y1 of the proportional valve; S15. Record the effective interval Y0-Y1 of the proportional valve.

5. A hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack according to claim 4, It is characterized in that Calibration of the second proportional valve, including: S31, the system is turned on, and the minimum opening of the second proportional valve is set to Y0; S32, small electric density pull load, set the hydrogen inlet pressure setting value, record the first proportional valve opening feedback value V1, then calibrate the opening of the second proportional valve to 0.5V1 + X0; the size of X0 refers to the first proportional valve opening feedback value, so that the calibrated second proportional valve opening is within the effective range of more than 20%; S33, pull the load electric density in turn, calibrate the opening of the second proportional valve, when the electric density reaches the middle, the opening of the second proportional valve is 0.5V1 + 0; S34, when the electric density reaches the maximum, the opening of the second proportional valve is calibrated to 0.5V1 - X1; the size of X1 refers to the feedback value of the opening of the first proportional valve, so that the calibrated opening of the second proportional valve is within the effective range of less than 80%; S35. Record the opening of the calibrated second proportional valve to complete the calibration.

6. A hydrogen pressure control method suitable for a high-power hydrogen fuel cell stack according to claim 1, It is characterized in that Select whether to use the first ejector and / or the second ejector according to the electrical density setting, including: Define small electric density, intermediate electric density and large electric density according to the hydrogen fuel cell system; When the electric density is low, the first three-way valve opens the branch without ejector and closes the branch connected to the ejector. Similarly, the second three-way valve also opens the branch without ejector, and the double proportional valve is used to control the hydrogen inlet pressure. When the intermediate electrical density is reached, the first three-way valve opens the branch connected to the ejector and closes the branch without the ejector. The second three-way valve opens the branch without the ejector, and the double proportional valve and the single ejector are used to control the hydrogen inlet pressure. When the electric density is high, the first three-way valve opens the branch connected to the ejector and closes the branch without the ejector. The second three-way valve opens the branch connected to the ejector, and the double proportional valve and double ejectors are used to control the hydrogen inlet pressure.

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