Control device and method for hydrogen circulation system of hydrogen fuel cell

Abstract

The invention relates to a control device and method for a hydrogen circulation system of a hydrogen fuel cell. The device comprises a hydrogen flow supply end; a hydrogen ejector; the hydrogen flow supply end is connected with the inlet end of the hydrogen ejector through the first proportional valve; the hydrogen flow supply end is connected with the outlet end of the hydrogen ejector through the second proportional valve; the inlet end of the electric pile is connected with the outlet end of the hydrogen ejector; the inlet end of the separation device is connected with the outlet end of the electric pile; a tail exhaust valve; the inlet end of the hydrogen circulating pump is connected with the outlet end of the separation device; a first switching valve; the pressure sensor and the humidity sensor are arranged at the inlet end of the electric pile. The efficiency and the reliability of the hydrogen circulation system can be improved, the cost and the power consumption of the system are reduced, and different technical requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel cell systems, and in particular to a control device and method for a hydrogen circulation system of a hydrogen fuel cell. Background Art

[0002] The application of hydrogen fuel cell systems in the commercial vehicle market is considered to be more advantageous. For commercial vehicles, they are usually matched with higher power systems (≥200kW). While considering the economy of hydrogen, such high-power systems also need to take into account system costs and technical selection of hydrogen circulation systems.

[0003] At present, hydrogen circulation is mainly achieved through hydrogen pumps and ejectors. Hydrogen pumps have the advantages of active regulation, fast response speed, and good temperature adaptability. However, their disadvantages are high noise, risk of oil leakage and high cost. In addition to traditional Roots pumps, vortex pumps have also appeared on the market. Vortex pumps have gained certain market applications due to their oil-free design and the ability to be connected in series with ejectors. The advantages of ejectors are low cost, small size and no parasitic power, but their disadvantages include poor low-temperature adaptability, poor reaction uniformity and easy water accumulation in the stack.

[0004] Therefore, in order to avoid the risk of a single solution and optimize costs, mainstream manufacturers currently use a hydrogen circulation solution that combines a hydrogen pump and an ejector. There are various combinations of hydrogen pumps and ejectors, including the initial parallel design and the later series design. Since the choices of hydrogen circulation by different manufacturers are different and new technology solutions continue to emerge, it is very necessary to study the hydrogen circulation solution for high-power systems.

[0005] The market generally believes that the hydrogen circulation scheme should strengthen the role of the ejector and weaken the role of the hydrogen pump. However, currently, the parallel configuration of the Roots pump and the ejector, or the series configuration of the vortex pump and the ejector are mostly used. Both methods have their shortcomings: in the parallel scheme, the circulation capacity of the ejector is not enhanced; in the series scheme, the vortex pump needs to increase the flow rate as the power increases, resulting in increased power consumption. Summary of the invention

[0006] To this end, the present invention provides a control device and method for a hydrogen circulation system of a hydrogen fuel cell, which can improve the efficiency and reliability of the hydrogen circulation system, reduce the cost and power consumption of the system, and adapt to different technical requirements.

[0007] In order to solve the above technical problems, the present invention provides a control device for a hydrogen circulation system of a hydrogen fuel cell, comprising: Hydrogen flow supply end; Hydrogen ejector; a first proportional valve, wherein the hydrogen flow supply end is connected to the inlet end of the hydrogen ejector through the first proportional valve; a second proportional valve, wherein the hydrogen flow supply end is connected to the outlet end of the hydrogen ejector through the second proportional valve; A fuel cell stack, used to realize an electrochemical reaction of hydrogen and oxygen, wherein substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen, and the inlet end of the fuel cell stack is connected to the outlet end of the hydrogen ejector; A separation device, used to separate substances generated by the electrochemical reaction to obtain liquid water, a mixture of impurity gases and unreacted hydrogen, the inlet end of the separation device being connected to the outlet end of the fuel cell stack; A tail valve connected to the outlet of the separation device for discharging the separated liquid water and impurity gas; A hydrogen circulation pump, the inlet end of the hydrogen circulation pump is connected to the outlet end of the separation device, and the hydrogen circulation pump is used to circulate unreacted hydrogen; a first switch valve, wherein the outlet end of the hydrogen circulation pump is connected to the outlet end of the hydrogen ejector through the first switch valve; a one-way valve, a second switch valve and a third switch valve, wherein the outlet end of the separation device is connected to the inlet end of the hydrogen ejector through the one-way valve and the third switch valve in sequence; one end of the second switch valve is connected between the first switch valve and the hydrogen circulation pump, and the other end is connected between the third switch valve and the inlet end of the hydrogen ejector; and A pressure sensor and a humidity sensor are disposed at the inlet end of the fuel cell stack.

[0008] In one embodiment of the present invention, the hydrogen circulation pump comprises a Roots pump or a vortex pump.

[0009] A method for controlling a hydrogen circulation system of a hydrogen fuel cell, using the control device of the hydrogen circulation system of the hydrogen fuel cell, the method comprising: When the hydrogen fuel cell system is running at low power or medium power, controlling to open the second switch valve and the first proportional valve and to close the second proportional valve, the first switch valve and the third switch valve; The hydrogen enters the fuel cell stack through the hydrogen flow supply end, the first proportional valve and the hydrogen ejector, and the substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector for circulation through the hydrogen circulation pump and the second switch valve, and the liquid water and impurity gas are discharged through the tail exhaust valve; When the hydrogen fuel cell system is running at high power, the second switch valve, the first proportional valve and the second proportional valve are controlled to be opened, and the first switch valve and the third switch valve are closed; The hydrogen enters the fuel cell stack through the first proportional valve, the hydrogen ejector and the second proportional valve through the hydrogen flow supply end, and the substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector for circulation through the hydrogen circulation pump and the second switch valve, and the liquid water and impurity gases are discharged through the tail exhaust valve.

[0010] In one embodiment of the present invention, it also includes: When the humidity sensor monitors a value higher than the set power, the control increases the opening of the second proportional valve and decreases the opening of the first proportional valve; when the humidity sensor monitors a value lower than the set power, the control decreases the opening of the second proportional valve and increases the opening of the first proportional valve.

[0011] A method for controlling a hydrogen circulation system of a hydrogen fuel cell, using the control device of the hydrogen circulation system of a hydrogen fuel cell as claimed in claim 1, characterized in that the method comprises: When the hydrogen fuel cell system is running at low power, controlling to open the first proportional valve and the first switch valve and to close the second proportional valve, the second switch valve and the third switch valve; The hydrogen enters the fuel cell stack through the hydrogen flow supply end, the first proportional valve and the hydrogen ejector, and the substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the fuel cell stack for circulation through the hydrogen circulation pump and the first switch valve, and the liquid water and impurity gas are discharged through the tail exhaust valve; When the hydrogen fuel cell system is running at medium power, the first proportional valve and the third switch valve are controlled to be opened and the second proportional valve, the first switch valve and the second switch valve are closed; The hydrogen enters the fuel cell stack through the hydrogen flow supply end, the first proportional valve and the hydrogen ejector, and the substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector for circulation through the one-way valve and the third switch valve, and the liquid water and impurity gas are discharged through the tail exhaust valve; When the hydrogen fuel cell system is running at high power, controlling to open the first proportional valve, the second proportional valve and the third switch valve and to close the first switch valve and the second switch valve; The hydrogen enters the fuel cell stack through the first proportional valve and the hydrogen ejector through the hydrogen flow supply end and enters the fuel cell stack through the second proportional valve. The substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector for circulation through the one-way valve and the third switch valve, and the liquid water and impurity gases are discharged through the tail exhaust valve.

[0012] In one embodiment of the present invention, it also includes: When the humidity sensor monitors a value higher than the set power, the control increases the opening of the second proportional valve and decreases the opening of the first proportional valve; when the humidity sensor monitors a value lower than the set power, the control decreases the opening of the second proportional valve and increases the opening of the first proportional valve.

[0013] A method for controlling a hydrogen circulation system of a hydrogen fuel cell, using the control device of the hydrogen circulation system of the hydrogen fuel cell, the method comprising: When the hydrogen fuel cell system is running at low power, controlling to open the first proportional valve and the second switch valve and to close the second proportional valve, the first switch valve and the third switch valve; The hydrogen enters the fuel cell stack through the hydrogen flow supply end, the first proportional valve and the hydrogen ejector, and the substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector for circulation through the hydrogen circulation pump and the second switch valve, and the liquid water and impurity gas are discharged through the tail exhaust valve; When the hydrogen fuel cell system is running at medium power, the first proportional valve and the third switch valve are controlled to be opened and the second proportional valve, the first switch valve and the second switch valve are closed; The hydrogen enters the fuel cell stack through the hydrogen flow supply end, the first proportional valve and the hydrogen ejector, and the substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector for circulation through the one-way valve and the third switch valve, and the liquid water and impurity gas are discharged through the tail exhaust valve; When the hydrogen fuel cell system is running at high power, controlling to open the first proportional valve, the second proportional valve and the third switch valve and to close the first switch valve and the second switch valve; The hydrogen enters the fuel cell stack through the first proportional valve and the hydrogen ejector through the hydrogen flow supply end and enters the fuel cell stack through the second proportional valve. The substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector for circulation through the one-way valve and the third switch valve, and the liquid water and impurity gases are discharged through the tail exhaust valve.

[0014] In one embodiment of the present invention, it also includes: When the humidity sensor monitors a value higher than the set power, the control increases the opening of the second proportional valve and decreases the opening of the first proportional valve; when the humidity sensor monitors a value lower than the set power, the control decreases the opening of the second proportional valve and increases the opening of the first proportional valve.

[0015] The above technical solution of the present invention has the following advantages compared with the prior art: The control device and method of the hydrogen circulation system of a hydrogen fuel cell described in the present invention improves the circulation capacity of the ejector while allowing the hydrogen pump to idle or stop, so as to improve the reliability of the hydrogen pump, thereby enhancing the durability and economy of the system. Taking into account the differences in control strategies of different system manufacturers, a method of replenishing air through a bypass valve is also introduced to appropriately adjust the humidity of the hydrogen entering the stack, thereby achieving flow replenishment and improving the efficiency and durability of the fuel cell system.

[0016] The present invention provides a variety of combinations of hydrogen pumps and ejectors (such as series and parallel), so that the hydrogen circulation system can select the optimal operation mode according to different power requirements. In low-power mode, the hydrogen is mainly circulated by the ejector to reduce energy consumption; in high-power mode, the hydrogen pump and ejector work together to ensure sufficient hydrogen flow and pressure, so that the system can adapt to various operating conditions.

[0017] The present invention is not limited to a specific type of hydrogen pump, but can also support a variety of pump types including Roots pumps and vortex pumps, greatly expanding the application range and flexibility of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0019] Figure 1 It is a schematic diagram of the fuel cell engine system of the present invention.

[0020] Figure 2 It is a schematic diagram of a control device for a hydrogen circulation system of a hydrogen fuel cell in Example 1 of the present invention.

[0021] Figure 3 It is a schematic diagram of a control device for a hydrogen circulation system of a hydrogen fuel cell in Example 2 of the present invention.

[0022] Figure 4 It is a schematic diagram of a control device for a hydrogen circulation system of a hydrogen fuel cell in Example 3 of the present invention.

[0023] Figure 5 It is a schematic diagram of a control device for a hydrogen circulation system of a hydrogen fuel cell in Example 4 of the present invention.

[0024] Description of the Figures in the Specification: 1. Hydrogen ejector; 2. The first proportional valve; 3. Second proportional valve; 4. Battery stack; 5. Separation device; 6. Tail exhaust valve; 7. Hydrogen circulation pump; 8. The first switch valve; 9. Second switch valve; 10. The third switch valve; 11. Check valve; 12. Pressure sensor; 13. Humidity sensor. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0026] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0027] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0028] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0029] Example 1 Fuel cell engine system schematic diagram Figure 1 As shown in the figure, it includes hydrogen supply system, air supply system, thermal management system, voltage inspection system, DCDC energy conversion system and ECU controller system. The actual fuel cell engine system requires coordinated control of the above systems to ensure its normal operation.

[0030] Reference Figure 2 As shown, this embodiment provides a control device for a hydrogen circulation system of a hydrogen fuel cell, comprising: Hydrogen flow supply end; Hydrogen ejector 1; A first proportional valve 2, wherein the hydrogen flow supply end is connected to the inlet end of the hydrogen ejector 1 through the first proportional valve 2; A second proportional valve 3, wherein the hydrogen flow supply end is connected to the outlet end of the hydrogen ejector 1 through the second proportional valve 3; The fuel cell stack 4 is used to realize the electrochemical reaction of hydrogen and oxygen, and the substances obtained by the reaction include water vapor, impurity gas and unreacted hydrogen. The inlet end of the fuel cell stack 4 is connected to the outlet end of the hydrogen ejector 1; A separation device 5 is used to separate substances generated by the electrochemical reaction to obtain a mixture of liquid water, impurity gases and unreacted hydrogen. The inlet end of the separation device 5 is connected to the outlet end of the battery stack 4. The tail valve 6 (including an exhaust valve and a drain valve) is connected to the outlet end of the separation device 5 and is used to discharge the separated liquid water and impurity gas; A hydrogen circulation pump 7, wherein the inlet end of the hydrogen circulation pump 7 is connected to the outlet end of the separation device 5, and the hydrogen circulation pump 7 is used to circulate unreacted hydrogen; A first switch valve 8, the outlet end of the hydrogen circulation pump 7 is connected to the outlet end of the hydrogen ejector 1 through the first switch valve 8; A one-way valve 11, a second switch valve 9 and a third switch valve 10, wherein the outlet end of the separation device 5 is connected to the inlet end of the hydrogen ejector 1 through the one-way valve 11 and the third switch valve 10 in sequence; one end of the second switch valve 9 is connected between the first switch valve 8 and the hydrogen circulation pump 7, and the other end is connected between the third switch valve 10 and the inlet end of the hydrogen ejector 1; and A pressure sensor 12 and a humidity sensor 13 are arranged at the inlet end of the fuel cell stack 4 .

[0031] The first proportional valve 2 is mainly used to provide the required fresh hydrogen flow rate under different system powers, and is kept stably and continuously open through the pressure sensor 12 at the inlet end of the fuel cell stack 4; The second proportional valve 3 not only has a flow supply function, in addition to timely flow replenishment under high power; it can also realize instantaneous flow replenishment when the tail valve 6 is opened, thereby reducing the pressure fluctuation at the inlet of the stack 4. And by cooperating with the first proportional valve 2, through the coordinated control of the two, and through the humidity sensor 13 at the inlet of the stack 4 to accurately control the humidity of the stack 4, the system reaction efficiency is improved, thereby improving the reliability and life of the fuel cell system. The second proportional valve 3 here can also be called a bypass proportional valve.

[0032] The hydrogen ejector 1 can play the role of circulating unreacted hydrogen, which is mainly achieved by cooperating with the front-end proportional valve. Under low power, the actual supply flow of the first proportional valve 2 is small, and the hydrogen ejector 1 only provides a passage and basically does not play an ejection effect; under medium power and high power, the actual supply flow of the second proportional valve 3 increases, and the hydrogen ejector 1 plays the role of circulating unreacted hydrogen.

[0033] The fuel cell stack 4 is an important place for realizing the electrochemical reaction of hydrogen and oxygen. Controlling the reaction flow, pressure and humidity inside it can effectively improve the economy, reliability and durability of the system.

[0034] The separation device 5 can use a water separator, membrane separation, etc. to achieve the effect of gas-liquid separation and gas separation, and ensure that the stack 4 will not be flooded, thereby improving the reaction efficiency. It can be understood that the outlet end of the separation device 5 refers to different separation outlets.

[0035] The hydrogen circulation pump 7 can realize the recycling of unreacted hydrogen to improve the utilization efficiency of hydrogen.

[0036] The one-way valve 11 can ensure that the high-pressure hydrogen at the front end will not leak to the rear end of the fuel cell stack 4, and at the same time, it can make the unreacted hydrogen flow back to the ejector for reuse.

[0037] The first switch valve 8, the second switch valve 9 and the third switch valve 10 realize the opening and closing of their branches through control signals, thereby enabling the hydrogen circulation system to realize different circulation modes.

[0038] The pressure sensor 12 adjusts the corresponding actions of the above components in real time through corresponding monitoring values ​​to achieve the target pressure under different power requirements of the system.

[0039] The humidity sensor 13 is mainly used to adjust the reaction humidity of the fuel cell stack 4. By monitoring its humidity value and coordinating and controlling the opening of the first proportional valve 2 and the second proportional valve 3, the target humidity under different power requirements of the system can be achieved.

[0040] The hydrogen circulation system requires coordinated control of the above components to ensure the normal operation of the actual system hydrogen circulation supply.

[0041] Example 2 Reference Figure 3 As shown, this embodiment provides a control method for a hydrogen circulation system of a hydrogen fuel cell, that is, a scheme in which a hydrogen circulation pump 7 and a hydrogen ejector 1 are connected in series, and the method includes: When the hydrogen fuel cell system is running at low power or medium power, the corresponding hydrogen inlet pressure is achieved by the hydrogen circulation pump 7 and the hydrogen ejector 1. At this time, the second switch valve 9 and the first proportional valve 2 are controlled to be opened and the second proportional valve 3, the first switch valve 8 and the third switch valve 10 are closed; The hydrogen enters the fuel cell stack 4 through the hydrogen flow supply end, the first proportional valve 2 and the hydrogen ejector 1. The hydrogen and oxygen undergo an electrochemical reaction, and the substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device 5 to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector 1 for circulation through the hydrogen circulation pump 7 and the second switch valve 9, and the liquid water and impurity gas are discharged through the tail exhaust valve 6; When the hydrogen fuel cell system is running at high power, the speed of the hydrogen pump is increasing, and the second proportional valve 3 needs to be controlled to open to supplement the insufficient hydrogen supply required by the system under high power; at this time, the second switch valve 9, the first proportional valve 2 and the second proportional valve 3 are controlled to open, and the first switch valve 8 and the third switch valve 10 are closed; The hydrogen passes through the hydrogen flow supply end through the first proportional valve 2, the hydrogen ejector 1 and the second proportional valve 3 respectively into the fuel cell stack 4. The hydrogen and oxygen undergo an electrochemical reaction, and the substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device 5 to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector 1 for circulation through the hydrogen circulation pump 7 and the second switch valve 9 , and the liquid water and impurity gases are discharged through the tail exhaust valve 6 .

[0042] It should be understood that in a hydrogen fuel cell system, low power, medium power and high power generally refer to the working state of the fuel cell system under different load conditions. For example, the low power state is when the fuel cell system outputs a relatively low electrical power, usually in the vehicle idling, low-speed cruising or light-load operation state. The medium power state is when the fuel cell system outputs a medium electrical power, which is suitable for medium load conditions, such as medium-speed cruising or normal city driving. The high power state is when the fuel cell system outputs a high electrical power, which is suitable for high load conditions, such as high-speed driving, acceleration or climbing.

[0043] In addition, the second proportional valve 3, in addition to being opened at high power to compensate for insufficient fresh hydrogen flow, also has the function of adjusting the humidity of hydrogen entering the stack. As the water content increases sharply and the operating temperature of the stack 4 is limited, the humidity inside the stack 4 increases. In order to control the appropriate reaction humidity, the second proportional valve 3 is opened, and this part of the dry hydrogen can appropriately adjust the humidity of the hydrogen entering the stack.

[0044] When the hydrogen fuel cell system is operating in each power range, when the humidity sensor 13 monitors a value higher than the set power, it controls to increase the opening of the second proportional valve 3 and to reduce the opening of the first proportional valve 2; when the humidity sensor 13 monitors a value lower than the set power, it controls to reduce the opening of the second proportional valve 3 and to increase the opening of the first proportional valve 2.

[0045] By coordinating and controlling the opening of the first proportional valve 2 and the second proportional valve 3, the humidity of the fuel cell stack 4 under different working conditions can be effectively adjusted to improve the reaction efficiency, thereby improving the durability and life of the system.

[0046] At the same time, the second proportional valve 3 can also instantly replenish hydrogen to reduce the pressure fluctuation of hydrogen entering the stack. It is opened in advance when the power of the fuel cell system is increased and the tail valve 6 is opened to reduce the pressure fluctuation of hydrogen entering the stack.

[0047] The above-mentioned function of the second proportional valve 3 is applicable to all power sections during the operation of the hydrogen fuel cell system. The second proportional valve 3 can be opened appropriately according to the humidity requirements of different power sections and the load-variable responsiveness of the system.

[0048] Example 3 Reference Figure 4 As shown, the hydrogen circulation pump 7 and the hydrogen ejector 1 are connected in parallel. This embodiment provides a control method for a hydrogen circulation system of a hydrogen fuel cell, and the method includes: When the hydrogen fuel cell system is running at low power, the corresponding hydrogen inlet pressure is reached through the branch of the hydrogen circulation pump 7; at this time, the first proportional valve 2 and the first switch valve 8 are controlled to be opened and the second proportional valve 3, the second switch valve 9 and the third switch valve 10 are closed; The hydrogen enters the fuel cell stack 4 through the hydrogen flow supply end, the first proportional valve 2 and the hydrogen ejector 1. The hydrogen and oxygen undergo an electrochemical reaction, and the substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device 5 to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the fuel cell stack 4 for circulation through the hydrogen circulation pump 7 and the first switch valve 8, and the liquid water and impurity gas are discharged through the tail exhaust valve 6; When the hydrogen fuel cell system is running at medium power, the corresponding hydrogen inlet pressure is mainly achieved through the hydrogen ejector 1 branch; at this time, the first proportional valve 2 and the third switch valve 10 are controlled to open and the second proportional valve 3, the first switch valve 8 and the second switch valve 9 are closed; The hydrogen enters the fuel cell stack 4 through the hydrogen flow supply end, the first proportional valve 2 and the hydrogen ejector 1. The hydrogen and oxygen undergo an electrochemical reaction, and the substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device 5 to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector 1 through the one-way valve 11 and the third switch valve 10 for circulation, and the liquid water and impurity gases are discharged through the tail exhaust valve 6; When the hydrogen fuel cell system is running at high power, the first proportional valve 2 and the circulation branch alone cannot reach the hydrogen flow rate required by the system, and the second proportional valve 3 needs to be opened and controlled to achieve this; at this time, the first proportional valve 2, the second proportional valve 3 and the third switch valve 10 are controlled to open and the first switch valve 8 and the second switch valve 9 are closed; The hydrogen enters the fuel cell stack 4 through the first proportional valve 2 and the hydrogen ejector 1 through the hydrogen flow supply end, and enters the fuel cell stack 4 through the second proportional valve 3. The substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device 5 to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector 1 for circulation through the one-way valve 11 and the third switch valve 10 , and the liquid water and impurity gases are discharged through the tail exhaust valve 6 .

[0049] In addition, the second proportional valve 3, in addition to being opened at high power to compensate for insufficient fresh hydrogen flow, also has the function of adjusting the humidity of hydrogen entering the stack. As the water content increases sharply and the operating temperature of the stack 4 is limited, the humidity inside the stack 4 increases. In order to control the appropriate reaction humidity, the second proportional valve 3 is opened, and this part of the dry hydrogen can appropriately adjust the humidity of the hydrogen entering the stack.

[0050] When the humidity sensor 13 monitors a value higher than the set power, it controls to increase the opening of the second proportional valve 3 and to reduce the opening of the first proportional valve 2; when the humidity sensor 13 monitors a value lower than the set power, it controls to reduce the opening of the second proportional valve 3 and to increase the opening of the first proportional valve 2.

[0051] By coordinating and controlling the opening of the first proportional valve 2 and the second proportional valve 3, the humidity of the fuel cell stack 4 under different working conditions can be effectively adjusted to improve the reaction efficiency, thereby improving the durability and life of the system.

[0052] At the same time, the second proportional valve 3 can also instantly replenish hydrogen to reduce the pressure fluctuation of hydrogen entering the stack. It is opened in advance when the power of the fuel cell system is increased and the tail valve 6 is opened to reduce the pressure fluctuation of hydrogen entering the stack.

[0053] The above-mentioned function of the second proportional valve 3 is applicable to all power sections during the operation of the hydrogen fuel cell system. The second proportional valve 3 can be opened appropriately according to the humidity requirements of different power sections and the load-variable responsiveness of the system.

[0054] Example 4 Reference Figure 5 As shown, this embodiment provides a control method for a hydrogen circulation system of a hydrogen fuel cell, the method comprising: When the hydrogen fuel cell system is running at low power, the circulation of unreacted hydrogen is mainly realized by the hydrogen circulation pump 7; at this time, the first proportional valve 2 and the second switch valve 9 are controlled to open and the second proportional valve 3, the first switch valve 8 and the third switch valve 10 are closed; The hydrogen enters the fuel cell stack 4 through the hydrogen flow supply end, the first proportional valve 2 and the hydrogen ejector 1. The hydrogen and oxygen undergo an electrochemical reaction, and the substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device 5 to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector 1 for circulation through the hydrogen circulation pump 7 and the second switch valve 9, and the liquid water and impurity gas are discharged through the tail exhaust valve 6; When the hydrogen fuel cell system is running at medium power, the main circulation function is mainly realized by the hydrogen ejector 1; at this time, the first proportional valve 2 and the third switch valve 10 are controlled to be opened and the second proportional valve 3, the first switch valve 8 and the second switch valve 9 are closed; The hydrogen enters the fuel cell stack 4 through the hydrogen flow supply end, the first proportional valve 2 and the hydrogen ejector 1. The hydrogen and oxygen undergo an electrochemical reaction, and the substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device 5 to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector 1 through the one-way valve 11 and the third switch valve 10 for circulation, and the liquid water and impurity gases are discharged through the tail exhaust valve 6; When the hydrogen fuel cell system is running at high power, the circulation loop alone is not enough to provide sufficient hydrogen flow, and the second proportional valve 3 needs to be opened to ensure the normal operation of the actual system; at this time, the first proportional valve 2, the second proportional valve 3 and the third switch valve 10 are controlled to open and the first switch valve 8 and the second switch valve 9 are closed; The hydrogen enters the fuel cell stack 4 through the first proportional valve 2 and the hydrogen ejector 1 through the hydrogen flow supply end, and enters the fuel cell stack 4 through the second proportional valve 3. The substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device 5 to obtain a mixture of liquid water, impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector 1 for circulation through the one-way valve 11 and the third switch valve 10 , and the liquid water and impurity gases are discharged through the tail exhaust valve 6 .

[0055] In this embodiment, the hydrogen circulation pump 7 is widely used, which can be a Roots pump or a vortex pump; at the same time, the scheme has lower requirements for the actual capacity of the pump; the Roots pump can be stopped or idle, and the vortex pump keeps idling, which can improve the reliability and durability of the pump. Overall, this embodiment is more helpful to improve the life and durability of the fuel cell system.

[0056] In addition, the second proportional valve 3, in addition to being opened at high power to compensate for insufficient fresh hydrogen flow, also has the function of adjusting the humidity of hydrogen entering the stack. As the water content increases sharply and the operating temperature of the stack 4 is limited, the humidity inside the stack 4 increases. In order to control the appropriate reaction humidity, the second proportional valve 3 is opened, and this part of the dry hydrogen can appropriately adjust the humidity of the hydrogen entering the stack.

[0057] When the humidity sensor 13 monitors a value higher than the set power, it controls to increase the opening of the second proportional valve 3 and to reduce the opening of the first proportional valve 2; when the humidity sensor 13 monitors a value lower than the set power, it controls to reduce the opening of the second proportional valve 3 and to increase the opening of the first proportional valve 2.

[0058] By coordinating and controlling the opening of the first proportional valve 2 and the second proportional valve 3, the humidity of the fuel cell stack 4 under different working conditions can be effectively adjusted to improve the reaction efficiency, thereby improving the durability and life of the system.

[0059] At the same time, the second proportional valve 3 can also instantly replenish hydrogen to reduce the pressure fluctuation of hydrogen entering the stack. It is opened in advance when the power of the fuel cell system is increased and the tail valve 6 is opened to reduce the pressure fluctuation of hydrogen entering the stack.

[0060] The above-mentioned function of the second proportional valve 3 is applicable to all power sections during the operation of the hydrogen fuel cell system. The second proportional valve 3 can be opened appropriately according to the humidity requirements of different power sections and the load-variable responsiveness of the system.

[0061] It should be noted that, in order to facilitate the demonstration of the concept, the present invention only uses one hydrogen ejector 1. However, the present invention is also applicable to the case of two or more hydrogen ejectors 1.

[0062] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A control device for a hydrogen circulation system of a hydrogen fuel cell, It is characterized in that include: Hydrogen flow supply end; Hydrogen ejector (1); A first proportional valve (2), wherein the hydrogen flow supply end is connected to the inlet end of the hydrogen ejector (1) through the first proportional valve (2); a second proportional valve (3), wherein the hydrogen flow supply end is connected to the outlet end of the hydrogen ejector (1) via the second proportional valve (3); A fuel cell stack (4) is used to realize an electrochemical reaction between hydrogen and oxygen, wherein substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen, and the inlet end of the fuel cell stack (4) is connected to the outlet end of the hydrogen ejector (1); A separation device (5) is used to separate substances generated by the electrochemical reaction to obtain liquid water, a mixture of impurity gases and unreacted hydrogen, the inlet end of the separation device (5) being connected to the outlet end of the fuel cell stack (4); A tail valve (6) connected to the outlet end of the separation device (5) and used to discharge the separated liquid water and impurity gas; A hydrogen circulation pump (7), the inlet end of the hydrogen circulation pump (7) being connected to the outlet end of the separation device (5), and the hydrogen circulation pump (7) being used to circulate unreacted hydrogen; a first switch valve (8), wherein the outlet end of the hydrogen circulation pump (7) is connected to the outlet end of the hydrogen ejector (1) via the first switch valve (8); a one-way valve (11), a second switch valve (9) and a third switch valve (10), wherein the outlet end of the separation device (5) is connected to the inlet end of the hydrogen ejector (1) via the one-way valve (11) and the third switch valve (10) in sequence; one end of the second switch valve (9) is connected between the first switch valve (8) and the hydrogen circulation pump (7), and the other end is connected between the third switch valve (10) and the inlet end of the hydrogen ejector (1); and A pressure sensor (12) and a humidity sensor (13) are arranged at the inlet end of the fuel cell stack (4).

2. A control device for a hydrogen circulation system of a hydrogen fuel cell according to claim 1, It is characterized in that The hydrogen circulation pump (7) comprises a Roots pump or a vortex pump.

3. A control method for a hydrogen circulation system of a hydrogen fuel cell, It is characterized in that Utilizing the control device of the hydrogen circulation system of the hydrogen fuel cell as claimed in claim 1, the method comprises: When the hydrogen fuel cell system is running at low power or medium power, controlling the second switch valve (9) and the first proportional valve (2) to be opened and the second proportional valve (3), the first switch valve (8) and the third switch valve (10) to be closed; The hydrogen enters the fuel cell stack (4) through the hydrogen flow supply end, the first proportional valve (2) and the hydrogen ejector (1), and the hydrogen and oxygen undergo an electrochemical reaction, whereby substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device (5) to obtain liquid water, a mixture of impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector (1) for circulation through the hydrogen circulation pump (7) and the second switch valve (9), and the liquid water and impurity gases are discharged through the tail exhaust valve (6); When the hydrogen fuel cell system is running at high power, the second switch valve (9), the first proportional valve (2) and the second proportional valve (3) are controlled to be opened, and the first switch valve (8) and the third switch valve (10) are closed; The hydrogen passes through the hydrogen flow supply end through the first proportional valve (2), the hydrogen ejector (1) and enters the fuel cell stack (4) and through the second proportional valve (3) to enter the fuel cell stack (4), and the hydrogen and oxygen undergo an electrochemical reaction, whereby substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device (5) to obtain liquid water, a mixture of impurity gases and unreacted hydrogen; Unreacted hydrogen enters the hydrogen ejector (1) for circulation through the hydrogen circulation pump (7) and the second switch valve (9), and liquid water and impurity gases are discharged through the tail exhaust valve (6).

4. A method for controlling a hydrogen circulation system of a hydrogen fuel cell as claimed in claim 3, It is characterized in that Also includes: When the humidity sensor (13) detects a value higher than the set power, the opening of the second proportional valve (3) is controlled to be increased, and the opening of the first proportional valve (2) is controlled to be decreased; when the humidity sensor (13) detects a value lower than the set power, the opening of the second proportional valve (3) is controlled to be decreased, and the opening of the first proportional valve (2) is increased.

5. A method for controlling a hydrogen circulation system of a hydrogen fuel cell, It is characterized in that The control device of the hydrogen circulation system of the hydrogen fuel cell as claimed in claim 1 is characterized in that the method comprises: When the hydrogen fuel cell system is running at low power, controlling to open the first proportional valve (2) and the first switch valve (8) and to close the second proportional valve (3), the second switch valve (9) and the third switch valve (10); The hydrogen enters the fuel cell stack (4) through the hydrogen flow supply end, the first proportional valve (2) and the hydrogen ejector (1), and the hydrogen and oxygen undergo an electrochemical reaction, whereby substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device (5) to obtain liquid water, a mixture of impurity gases and unreacted hydrogen; Unreacted hydrogen enters the fuel cell stack (4) for circulation through the hydrogen circulation pump (7) and the first switch valve (8), and liquid water and impurity gases are discharged through the tail exhaust valve (6); When the hydrogen fuel cell system is running at medium power, the first proportional valve (2) and the third switch valve (10) are controlled to be opened, and the second proportional valve (3), the first switch valve (8) and the second switch valve (9) are closed; The hydrogen enters the fuel cell stack (4) through the hydrogen flow supply end, the first proportional valve (2) and the hydrogen ejector (1), and the hydrogen and oxygen undergo an electrochemical reaction, whereby substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device (5) to obtain liquid water, a mixture of impurity gases and unreacted hydrogen; Unreacted hydrogen enters the hydrogen ejector (1) through the one-way valve (11) and the third switch valve (10) for circulation, and liquid water and impurity gases are discharged through the tail exhaust valve (6); When the hydrogen fuel cell system is running at high power, the first proportional valve (2), the second proportional valve (3) and the third switch valve (10) are controlled to open and the first switch valve (8) and the second switch valve (9) are closed; The hydrogen enters the fuel cell stack (4) through the first proportional valve (2) and the hydrogen ejector (1) through the hydrogen flow supply end, and enters the fuel cell stack (4) through the second proportional valve (3), and the substances obtained by the electrochemical reaction of hydrogen and oxygen include water vapor, impurity gas and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device (5) to obtain liquid water, a mixture of impurity gases and unreacted hydrogen; Unreacted hydrogen enters the hydrogen ejector (1) for circulation through the one-way valve (11) and the third switch valve (10), and liquid water and impurity gases are discharged through the tail exhaust valve (6).

6. A method for controlling a hydrogen circulation system of a hydrogen fuel cell according to claim 5, It is characterized in that Also includes: When the humidity sensor (13) detects a value higher than the set power, the opening of the second proportional valve (3) is controlled to be increased, and the opening of the first proportional valve (2) is controlled to be decreased; when the humidity sensor (13) detects a value lower than the set power, the opening of the second proportional valve (3) is controlled to be decreased, and the opening of the first proportional valve (2) is increased.

7. A method for controlling a hydrogen circulation system of a hydrogen fuel cell, It is characterized in that The control device of the hydrogen circulation system of the hydrogen fuel cell as claimed in claim 1 is characterized in that the method comprises: When the hydrogen fuel cell system is running at low power, controlling to open the first proportional valve (2) and the second switch valve (9) and to close the second proportional valve (3), the first switch valve (8) and the third switch valve (10); The hydrogen enters the fuel cell stack (4) through the hydrogen flow supply end, the first proportional valve (2) and the hydrogen ejector (1), and the hydrogen and oxygen undergo an electrochemical reaction, whereby substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device (5) to obtain liquid water, a mixture of impurity gases and unreacted hydrogen; The unreacted hydrogen enters the hydrogen ejector (1) for circulation through the hydrogen circulation pump (7) and the second switch valve (9), and the liquid water and impurity gases are discharged through the tail exhaust valve (6); When the hydrogen fuel cell system is running at medium power, the first proportional valve (2) and the third switch valve (10) are controlled to be opened, and the second proportional valve (3), the first switch valve (8) and the second switch valve (9) are closed; The hydrogen enters the fuel cell stack (4) through the hydrogen flow supply end, the first proportional valve (2) and the hydrogen ejector (1), and the hydrogen and oxygen undergo an electrochemical reaction, whereby substances obtained by the reaction include water vapor, impurity gases and unreacted hydrogen; The substances generated by the electrochemical reaction are separated by the separation device (5) to obtain liquid water, a mixture of impurity gases and unreacted hydrogen; Unreacted hydrogen enters the hydrogen ejector (1) through the one-way valve (11) and the third switch valve (10) for circulation, and liquid water and impurity gases are discharged through the tail exhaust valve (6); When the hydrogen fuel cell system is running at high power, the first proportional valve (2), the second proportional valve (3) and the third switch valve (10) are controlled to open and the first switch valve (8) and the second switch valve (9) are closed; The hydrogen enters the fuel cell stack (4) through the hydrogen flow supply end, through the first proportional valve (2) and the hydrogen ejector (1), and enters the fuel cell stack (4) through the second proportional valve (3). The hydrogen and oxygen undergo an electrochemical reaction, and substances obtained by the reaction include water vapor, impurity gases, and unreacted hydrogen. The substances generated by the electrochemical reaction are separated by the separation device (5) to obtain liquid water, a mixture of impurity gases and unreacted hydrogen; Unreacted hydrogen enters the hydrogen ejector (1) for circulation through the one-way valve (11) and the third switch valve (10), and liquid water and impurity gases are discharged through the tail exhaust valve (6).

8. A method for controlling a hydrogen circulation system of a hydrogen fuel cell according to claim 7, It is characterized in that Also includes: When the humidity sensor (13) detects a value higher than the set power, the opening of the second proportional valve (3) is controlled to be increased, and the opening of the first proportional valve (2) is controlled to be decreased; when the humidity sensor (13) detects a value lower than the set power, the opening of the second proportional valve (3) is controlled to be decreased, and the opening of the first proportional valve (2) is increased.

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