Method and device for controlling fault power reduction operation of fuel cell system

Abstract

The invention discloses a control method and device for fault power reduction operation of a fuel cell system. The device comprises an electric pile, a hydrogen path, an air path and a water path, and the hydrogen path comprises a nitrogen flow meter, a hydrogen inlet valve, a proportional valve, double ejectors, a safety valve, a steam-water separator, a nitrogen discharge valve and a water discharge electromagnetic valve. According to the method, the operation condition of the fuel cell system is monitored in real time, and when the fuel cell system breaks down during operation, the rotating speed of each part and the pressure of each cavity of the galvanic pile are reduced according to the set loading rate and the power value correspondingly set during fault power reduction, so that the power of the fuel cell system is stably reduced, and the service life of the fuel cell system is prolonged. Therefore, the system can still provide certain electric power and maintain basic functions of the system even in a fault mode, the stability of the fuel cell system is guaranteed especially in a key application scene, but the fuel cell system still recovers to a normal power output mode when the fault recovers.

Description

Technical Field

[0001] The invention belongs to the field of fuel cell control, and in particular relates to a control method for a fuel cell system to operate at reduced power when a fault occurs. Background Art

[0002] Hydrogen energy is a fuel cell that generates electricity through the chemical reaction of hydrogen and oxygen. It can usually provide stable power output under normal working conditions. However, in some cases, the fuel cell may fail, resulting in a decrease in its performance. In the event of a failure, the output power of the fuel cell may decrease, directly affecting the reliability and safety of the system. Reduced power operation can be used as an emergency measure to ensure that the system can continue to operate in a faulty state and avoid complete failure.

[0003] During the operation of the fuel cell system, if the system hydrogen inlet pressure is too low or too high, the stack hydrogen inlet pressure is too low or too high, the hydrogen-air pressure difference is too high or too low, the stack inlet air temperature is too high, the fuel cell stack single chip voltage is too low, the air compressor software and hardware warning failure, the water pump software and hardware warning failure, the hydrogen pump software and hardware warning failure, all of these may cause the fuel cell to need emergency shutdown, directly affecting the stability and reliability of the fuel cell system. According to this technology, when a fuel cell system fails, it needs to reduce power. According to different judgment thresholds, the power reduction is divided into the first level, the second level, and the idle speed, so that after the system stabilizes or the fault is resolved, it automatically exits the power reduction mode and continues to pull the original power.

[0004] The existing fuel cell system handles faults in a way that the fuel cell controller sets thresholds for various operating parameters and handles component faults according to the specified fault level. When the threshold and fault rules are triggered, the system may be shut down normally or shut down by emergency power and gas cut-off according to the fault level. This will cause frequent faults in the fuel cell system and increase the fault rate. The system may shut down due to a false alarm of a component or the value of a sensor shifts over a period of time, affecting vehicle stability and failing to meet the redundancy of the system design. Summary of the invention

[0005] The present invention provides a control method and device for the power reduction operation of a fuel cell system in the event of a fault, which monitors the operating status of the fuel cell system in real time. When a fault occurs in the fuel cell system during operation, the rotation speed of each component and the pressure of each cavity of the stack are reduced according to a set load rate and a power value corresponding to the set power reduction during the fault, so that the power of the fuel cell system is steadily reduced, so that the system can still provide a certain amount of electricity even in a fault mode to maintain the basic functions of the system, especially in key application scenarios (such as transportation vehicles, ships, drones, emergency power supplies, etc.), to ensure the stability of the fuel cell system, but when the fault is restored, the fuel cell system still returns to a normal power output mode.

[0006] A fuel cell system fault power reduction operation device, comprising a fuel cell stack, a hydrogen path, an air path and a water path;

[0007] The hydrogen circuit includes a nitrogen flow meter, a hydrogen inlet valve, a proportional valve, a double ejector, a safety valve, a steam-water separator, a nitrogen exhaust valve and a water discharge solenoid valve;

[0008] The air circuit includes an air filter, an air compressor, an intercooler and a humidifier;

[0009] The water circuit includes a cooling fan, an expansion tank, a water pump, a PTC, a three-way valve and a particle filter;

[0010] The water outlet of the stack is connected to the water pump, the cooling fan, the three-way valve and the particle filter in sequence, and the particle filter is connected to the water inlet of the stack; the water pump is also connected to the PTC and the three-way valve through a pipeline; an expansion water tank is connected to the pipeline between the stack and the water pump, and the exhaust port of the expansion water tank is also connected to the cooling fan;

[0011] In the air path, the air filter is connected to the air compressor, the intercooler and the humidifier in sequence; the humidifier is connected to the stack air inlet and the stack air outlet interfaces of the stack through two pipelines; the intercooler is also connected to the stack air inlet interface of the stack through a pipeline;

[0012] In the hydrogen path, the nitrogen flow meter, hydrogen inlet valve, proportional valve, double ejector, and safety valve are connected to the fuel cell stack in sequence; the hydrogen return port of the double ejector is connected to the steam-water separator through a pipeline; the safety valve is also connected to the nitrogen exhaust valve and steam-water separator in sequence;

[0013] The air wet side outlet of the humidifier meets the liquid outlet of the steam-water separator at a mixing point through a pipeline, and a drainage solenoid valve is arranged on the pipeline between the steam-water separator and the mixing point; a DCDC controller is also arranged on the high-voltage output line of the battery stack.

[0014] Preferably, the mixing point is connected to a silencer and then emptied.

[0015] Preferably, the safety valve is also connected to the mixing point through a pipeline; the stack air outlet of the fuel cell stack is connected to the mixing point, and a one-way valve is provided on the pipeline between the fuel cell stack and the mixing point.

[0016] Preferably, a flow meter is also provided on the pipeline between the air compressor and the air filter; the air compressor is connected to an air compressor controller, and its function is to control the speed and start and stop of the air compressor through the air compressor controller.

[0017] Preferably, the particle filter is also connected to a liquid flow meter and an intercooler through pipelines, and the intercooler is connected to the water pump; the intercooler is also connected to a bypass valve and a battery stack in sequence.

[0018] Preferably, a radiator outlet temperature sensor is provided on the outlet pipe of the cooling fan; a battery stack water inlet temperature sensor is provided at the water inlet of the battery stack; a battery stack water outlet temperature sensor is provided at the outlet of the battery stack; and a battery stack air inlet pressure sensor is provided at the air inlet of the battery stack.

[0019] Preferably, a system air inlet pressure sensor is provided on the pipeline between the air filter and the flowmeter; a stack air inlet temperature sensor is provided at the air inlet of the fuel cell stack; a hydrogen medium-pressure pressure sensor is provided on the pipeline between the hydrogen inlet valve and the proportional valve; a hydrogen low-pressure pressure sensor is provided at the hydrogen inlet of the fuel cell stack; and a hydrogen outlet pressure sensor is provided at the hydrogen outlet of the fuel cell stack.

[0020] In order to reduce the interference of abnormal and serious faults, the present invention attempts to automatically restore the fuel cell system parameters without stopping in the power reduction mode, provides a time window for fault diagnosis, allows the system to perform self-detection and fault analysis, and ensures as quickly as possible that the fuel cell system power can be restored when the fault is cleared. Or, when the same fault is triggered continuously, the power is reduced by one level, two levels, or directly to idle mode according to the number of triggers and the set fault threshold, rather than directly shutting down the system when the fault is triggered.

[0021] A control method for a fuel cell system to reduce power when a fault occurs, comprising the following steps:

[0022] (1) Power on the fuel cell system, wake up the fuel cell controller, activate the fuel cell system fault real-time monitoring module, and conduct self-check of the fuel cell system. The fault monitoring module receives signals from various electrical devices in real time (such as whether the value of the hydrogen medium-pressure sensor is displayed within the pressure range required for the fuel cell system to work, whether the fuel cell air compressor, water pump, etc. are in standby mode, and whether there are any faults after self-checking). This is used to determine whether any electrical device is in an abnormal working state. Multiple system operating parameters are used as input conditions for the real-time fault monitoring module.

[0023] (2) The fuel cell fault real-time monitoring module compares the numerical value input by each electrical device with the fault threshold set by the monitoring module. If a fault is triggered, it determines the level of power reduction fault or serious shutdown fault, and releases the fault information to the upper-level control device so that the upper-level control device can take corresponding actions; the upper-level control device includes a car, a ship, a drone, a fixed power station or a backup power supply;

[0024] (3) The fuel cell system fault monitoring module determines that a power reduction level 1 fault has occurred, and at the same time determines the difference between the required power P1 given by the upper level control device and the power threshold P3 set at the power reduction level 1 as the current first power P2 that the current fuel cell system needs to respond to;

[0025] (4) Because the fuel cell system has idle power, it is to prevent the fuel cell from running at a high potential for a long time and causing carbon corrosion, thereby causing the life of the fuel cell system to decay rapidly. Therefore, it is necessary to determine whether the current first power P2 is less than or equal to the idle power P5. If it is less, the idle power P5 is output in response; if it is greater, the current first power P2 is maintained and the power input is used as the stack load current value under the fault state of the fuel cell system, reducing and limiting the air and hydrogen intake and the frequency of drainage, and at the same time transmitting the fault information to the upper level control device as "Fuel system XXX fault, power reduction mode one level";

[0026] (5) Since the power value of the fuel cell is distributed according to the electric density point, the power generally has a large range. In order to distinguish whether the fault is serious, two levels of power reduction are set. The first level of power reduction is to reduce the existing power by (20-30)% as the fault limit output power, and the second level of power reduction is to reduce the existing power by (50-70)% as the fault limit output power. When the fuel cell system fault monitoring module determines that it has entered the second level of power reduction fault, it also determines the difference between the required power P1 given by the upper level control device and the power threshold P6 set for the second level of power reduction as the current second power P4 that the current fuel cell system needs to respond to; it determines whether the current second power P4 is less than or equal to the idle power P5. If it is less than, the idle power P5 is output to respond. If it is greater than, the current second power P4 is maintained to output and respond. This power input is used as the stack load current value under the fault state of the fuel cell system, and the air and hydrogen intake and drainage frequency are rapidly reduced and limited. At the same time, the fault information is transmitted to the upper level control device as "Fuel system XXX fault, power reduction second level mode";

[0027] (6) The fuel cell system fault monitoring module determines that it has entered a serious level 3 fault, and the fault holding time must be greater than or equal to the fault time T2. After it is determined to be a real verification fault, the fault information is transmitted to the upper-level control device as "Fuel system XXX fault, serious fault, system shutdown". At the same time, the fuel cell system fails and shuts down, and the upper-level device needs to switch to pure electric mode and continue to drive in pure electric mode;

[0028] (7) When the fuel cell system is in a power reduction level 1 or 2 fault state, the system determines the delay T1 to allow the fault detection module to detect the system state in real time. For example, when one or more parameters are restored to within the fault threshold, it can be determined that the system has not triggered a fault and returns to normal mode from the original power reduction mode, thereby responding to the power demand P1 given by the upper-level control device and canceling the fault information transmitted to the outside. At this time, the fuel cell system needs to increase the intake of hydrogen and air first, and then increase the current value of the fuel cell stack to meet the power demand P1. If in the case of a power reduction level 2 fault, one or more parameters are restored to within the power reduction level 1 fault threshold, it can be determined that the fuel cell system has returned to the power reduction level 1 state, and the current second power P4 becomes the current first power P2. The fuel cell system can increase the intake of hydrogen and air and increase the current value of the fuel cell stack to meet the current first power P2.

[0029] In the above method, when the fuel cell system judges the state of the entire system, no matter it is a fault state or a non-fault state, the corresponding system power emitted needs to re-judge the state of the fuel cell system within the delay time T1, and continuously cycle the entire judgment logic to achieve the real-time performance of the fuel cell fault monitoring module, and the corresponding operation needs to be executed in the corresponding state.

[0030] In the above method, according to different faults and fault severity, the corresponding first-level power reduction P2 and second-level power reduction P4 need to be obtained after further bench test calibration; the delay time T1 of the entire fault real-time monitoring module also needs to be obtained through calibration according to different fault responses.

[0031] In the above method, when the fuel cell system jumps from the power reduction mode to the normal mode, when the power increases, it is necessary to first increase the intake of hydrogen and air, and then load the current at a load slope of (30-50) A / s to meet the required power P1 given by the upper-level control device; when the fuel cell system jumps from the normal mode to the power reduction level one or two, when the power decreases, it is necessary to first quickly reduce the current at a load reduction slope of (45-60) A / s to prevent shutdown caused by rapid deviation of operating parameters at high power to the fault threshold set by the severe third-level fault mode. At this time, the intake of air and hydrogen is rapidly reduced to achieve the purpose of rapid load reduction to stabilize the fuel cell system parameters and gradually restore to a normal state, thereby ensuring the stability and reliability of the system.

[0032] Compared with the prior art, the advantages of the present invention are:

[0033] In the event of a fuel cell system failure, the reduced power operation mode allows the system to continue operating rather than shutting down completely. This approach ensures continuous power supply in critical applications (such as transportation, emergency power supply, etc.), thereby improving the overall reliability of the system;

[0034] When a fault occurs, the reduced power operation mode can provide maintenance personnel with more time and space to diagnose and repair the fault without having to shut down the system immediately. This approach can reduce downtime and improve system reliability;

[0035] By reducing power output, the system can reduce stress on the fuel cell, reducing the risk of overheating and other potential damage. This gentle operating state helps extend the life of the fuel cell and reduce maintenance and replacement costs; BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The invention relates to a fuel cell system fault power reduction operation device.

[0037] Figure 2 Flow chart of the control method of the present invention.

[0038] The components in the figure are as follows: cooling fan 1, expansion tank 2, DCDC controller 3, battery stack 4, water pump 5, PTC 6. Three-way valve 7. Particulate filter 8. Radiator outlet temperature sensor 9. Stack water outlet temperature sensor 10. Stack water inlet temperature sensor 11. Liquid flow meter 12. Air compressor controller 13. Air filter 14. System air inlet pressure sensor 15. Flow meter 16. Air compressor 17. Intercooler 18. Temperature sensor 19. Humidifier 20. Air shut-off valve 21. Bypass valve 22. Stack air inlet temperature sensor 23. Stack air inlet pressure sensor 24. Throttle 25. Check valve 26. Mixing point 27. Muffler 28. Nitrogen flow meter 29. Hydrogen inlet valve 30. Hydrogen medium pressure sensor 31. Proportional valve 32. Double ejector 33. Safety valve 34. Hydrogen low pressure sensor 35. Hydrogen outlet pressure sensor 36. Steam-water separator 37. Nitrogen exhaust valve 38. Drain solenoid valve 39. DETAILED DESCRIPTION

[0039] The following description combines specific illustrations to explain the technical solution so as to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and similar generalized embodiments made by ordinary technicians in the field without creative work are all within the scope of protection of the present invention.

[0040] Example 1

[0041] like Figure 1 As shown, a fuel cell system fault power reduction operation device includes a fuel cell stack 4, a hydrogen circuit, an air circuit and a water circuit; the hydrogen circuit includes a nitrogen flow meter 29, a hydrogen inlet valve 30, a proportional valve 32, a double ejector 33, a safety valve 34, a steam-water separator 37, a nitrogen exhaust valve 38 and a water discharge solenoid valve 39; the air circuit includes an air filter 14, an air compressor 17, an intercooler 18 and a humidifier 20; the water circuit includes a cooling fan 1, an expansion water tank 2, a water pump 5, a PTC 6, a three-way valve 7 and a particle filter 8;

[0042] In this embodiment, the water outlet of the battery stack 4 is connected to the water pump 5, the cooling fan 1, the three-way valve 7 and the particle filter 8 in sequence, and the particle filter 8 is connected to the water inlet of the battery stack 4; the water pump 5 is also connected to the PTC 6 and the three-way valve 7 through a pipeline; the pipeline between the battery stack 4 and the water pump 5 is connected to the expansion water tank 2, and the exhaust port of the expansion water tank 2 is also connected to the cooling fan 1;

[0043] In the air path of this embodiment, the air filter 14 is connected to the air compressor 17, the intercooler 18 and the humidifier 20 in sequence; the humidifier 20 is connected to the stack air inlet and the stack air outlet interface of the stack 4 through two pipelines; the intercooler 18 is also connected to the stack air inlet interface of the stack 4 through a pipeline;

[0044] In the hydrogen circuit of this embodiment, the nitrogen flowmeter 29, the hydrogen inlet valve 30, the proportional valve 32, the double ejector 33, and the safety valve 34 are connected to the fuel cell stack 4 in sequence; the hydrogen return port of the double ejector 33 is connected to the steam-water separator 37 through a pipeline; the safety valve 34 is also connected to the nitrogen exhaust valve 38 and the steam-water separator 37 in sequence;

[0045] The air wet side outlet of the humidifier 20 meets the liquid outlet of the steam-water separator 37 at the mixing point 27 through a pipeline, and a drainage solenoid valve 39 is arranged on the pipeline between the steam-water separator 37 and the mixing point 27; a DCDC controller 3 is also arranged on the high-voltage output line of the battery stack 4.

[0046] The mixing point 27 is connected to the muffler 28 and then emptied; the safety valve 34 is also connected to the mixing point 27 through a pipeline; the stack air outlet of the stack 4 is connected to the mixing point 27, and a one-way valve 26 is provided on the pipeline between the stack 4 and the mixing point 27. A flow meter 16 is also provided on the pipeline between the air compressor 17 and the air filter 14; the air compressor 17 is connected to the air compressor controller 13, and its function is to control the speed and start and stop of the air compressor through the air compressor controller. The particle filter 8 is also connected to the liquid flow meter 12 and the intercooler 18 through a pipeline, and the intercooler 18 is connected to the water pump 5; the intercooler 18 is also connected to the bypass valve 22 and the stack 4 in sequence. A radiator outlet temperature sensor 9 is provided on the outlet pipe of the cooling fan 1; a battery stack water inlet temperature sensor 11 is provided at the battery stack water inlet of the battery stack 4; a battery stack water outlet temperature sensor 10 is provided at the outlet of the battery stack 4; and a battery stack air inlet pressure sensor 24 is provided at the air inlet of the battery stack 4.

[0047] In this embodiment, a system air inlet pressure sensor 15 is provided on the pipeline between the air filter 14 and the flow meter 16; a stack air inlet temperature sensor 23 is provided at the air inlet of the fuel cell 4; a hydrogen medium-pressure pressure sensor 31 is provided on the pipeline between the hydrogen inlet valve 30 and the proportional valve 32; a hydrogen low-pressure pressure sensor 35 is provided at the hydrogen inlet of the fuel cell; and a hydrogen outlet pressure sensor 36 is provided at the hydrogen outlet of the fuel cell.

[0048] Example 2

[0049] like Figure 1As shown, the fuel cell is composed of a series of electrical equipment and electrical appliances such as hydrogen medium pressure sensor 1, hydrogen low pressure sensor 2, DCDC controller 3, stack water outlet temperature sensor 4, fuel cell water pump 5, radiator outlet temperature sensor 6, three-way valve 7, stack water inlet temperature sensor 8, system air inlet pressure sensor 9, air flow meter 10, fuel cell air compressor 11, intercooler after temperature sensor 12, bypass valve 13, air stop valve 14, stack air inlet temperature sensor 15, stack air inlet pressure sensor 16, throttle 17, fuel cell stack 18, hydrogen outlet pressure sensor 19, and drainage solenoid valve 20. It exchanges electrical signals and data with the fuel cell controller, and is supervised by the system fault real-time monitoring module of the fuel cell controller to ensure the stable operation of the entire fuel cell system.

[0050] In this embodiment, a control method for a fuel cell system to reduce power when a fault occurs includes the following steps:

[0051] 1. Power on the fuel cell system, wake up the fuel cell controller at the same time, activate the real-time monitoring module for fuel cell system faults, and conduct self-check of the fuel cell system. The fault monitoring module collects signals from various electrical devices in real time (such as whether the value of the hydrogen medium-pressure sensor is displayed within the pressure range required for the fuel cell system to work, whether the fuel cell air compressor, water pump, etc. are in standby mode, and whether there are any faults after self-checking). This is used to determine whether any electrical device is in an abnormal working state, and multiple system operating parameters are used as input conditions for the real-time monitoring module for faults. In this embodiment, the real-time monitoring module for fuel cell system faults includes the system air inlet pressure (system air inlet pressure sensor 15) , system hydrogen inlet pressure (hydrogen medium pressure sensor 31), fuel cell hydrogen inlet pressure (hydrogen low pressure pressure sensor 35), fuel cell hydrogen outlet pressure (hydrogen outlet pressure sensor 36), hydrogen-air pressure difference, fuel cell single chip voltage, fuel cell water path inlet temperature (fuel cell water inlet temperature sensor 11), fuel cell water path outlet temperature (fuel cell water outlet temperature sensor 10), fuel cell air path inlet temperature (fuel cell air inlet pressure sensor 24), fuel cell air path inlet pressure (fuel cell air inlet temperature sensor 23), air compressor status, water pump status, hydrogen pump status, proportional valve opening status (proportional valve 32), DCDC controller status (DCDC controller 3), etc.;

[0052] 2. The fuel cell fault real-time monitoring module compares the input values ​​of each electrical device with the fault threshold set by the monitoring module. When a fault is triggered, it determines the level of power reduction fault or serious shutdown fault level, and releases the fault information to the upper-level control device so that the upper-level control device can take corresponding actions (the upper-level control device includes but is not limited to automobiles, ships, drones, fixed power stations, backup power supplies, etc.);

[0053] 3. The fuel cell system fault monitoring module determines that a power reduction level 1 fault has occurred, and at the same time determines the difference between the required power P1 given by the upper level control device and the power threshold P3 set at the power reduction level 1 as the current first power P2 that the current fuel cell system needs to respond to;

[0054] 4. Because the fuel cell system has idle power, it is to prevent the fuel cell from running at high potential for a long time and causing carbon corrosion, thereby causing the life of the fuel cell system to decay rapidly. Therefore, it is necessary to determine whether the current first power P2 is less than or equal to the idle power P5. If it is less, the idle power P5 is output in response. If it is greater, the current first power P2 is output in response. This power input is used as the stack load current value under the fault state of the fuel cell system, reducing and limiting the air and hydrogen intake and drainage frequency, and at the same time transmitting the fault information to the upper level control device as "Fuel system XXX fault, power reduction mode one level";

[0055] 5. Since the power value of the fuel cell is distributed according to the electric density point, the power generally has a large range. In order to distinguish whether the fault is serious, two levels of power reduction are set. The first level of power reduction is to reduce the existing power by (20-30)% as the fault limit output power, and the second level of power reduction is to reduce the existing power by (50-70)% as the fault limit output power. When the fuel cell system fault monitoring module determines that it has entered the second level of power reduction fault, it also determines the difference between the required power P1 given by the upper level control device and the power threshold P6 set for the second level of power reduction as the current second power P4 that the current fuel cell system needs to respond to; it determines whether the current second power P4 is less than or equal to the idle power P5. If it is less than, the idle power P5 is output to respond. If it is greater than, the current second power P4 is maintained to respond. This power input is used as the stack load current value under the fault state of the fuel cell system, and the air and hydrogen intake and drainage frequency are rapidly reduced and limited. At the same time, the fault information is transmitted to the upper level control device as "Fuel system XXX fault, power reduction second level mode";

[0056] 6. The fuel cell system fault monitoring module determines that it has entered a serious level 3 fault. The fault holding time must be greater than or equal to the fault time T2. After it is determined to be a real verification fault, the fault information is transmitted to the upper-level control device as "Fuel system XXX fault, serious fault, system shutdown". At the same time, the fuel cell system fails and shuts down. The upper-level device needs to switch to pure electric mode and continue to drive in pure electric mode;

[0057] 7. When the fuel cell system judges the status of the entire system, whether it is a fault state or a non-fault state, the corresponding system power must be re-judged within the delay time T1, and the entire cycle judgment logic is continuously repeated to achieve the real-time performance of the fuel cell fault monitoring module. In the corresponding state, the corresponding operation needs to be executed;

[0058] 8. When the fuel cell system is in a power reduction level 1 or 2 fault state, according to the system judgment delay T1, the fault detection module detects the system state in real time. For example, when one or more parameters are restored to within the fault threshold, it can be determined that the system has not triggered a fault, and returns to the normal mode from the original power reduction mode, thereby responding to the required power P1 given by the upper-level control device, and canceling the fault information transmitted to the outside. At this time, the fuel cell system needs to increase the intake of hydrogen and air first, and then pull the current value of the fuel cell stack to meet the required power P1; if in the case of a power reduction level 2 fault, one or more parameters are restored to within the power reduction level 1 fault threshold, it can be determined that the fuel cell system returns to the power reduction level 1 state, and the current second power P4 becomes the current first power P2. The fuel cell system can increase the intake of hydrogen and air, and pull the current value of the fuel cell stack to meet the current first power P2;

[0059] 9. According to different faults and fault severity, the corresponding first-level power reduction P2 and second-level power reduction P4 need to be obtained after further bench test calibration; the delay time T1 of the entire fault real-time monitoring module also needs to be obtained through calibration according to different fault responses;

[0060] When the fuel cell system switches from the power reduction mode to the normal mode, when the power increases, it is necessary to first increase the intake of hydrogen and air, and then load the current at a load slope of (30-50) A / s to meet the power demand P1 given by the upper-level control device; when the fuel cell system switches from the normal mode to the power reduction level one or two, when the power decreases, it is necessary to first quickly reduce the current at a load reduction slope of (45-60) A / s to prevent shutdown caused by rapid deviation of operating parameters at high power to the fault threshold set by the severe level three fault mode. At this time, the intake of air and hydrogen is rapidly reduced to achieve the purpose of rapid load reduction to stabilize the fuel cell system parameters and gradually restore to normal state, thereby ensuring the stability and reliability of the system.

[0061] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A fuel cell system fault power reduction operation device, characterized in that: It includes a battery stack (4), a hydrogen path, an air path and a water path; The hydrogen circuit comprises a nitrogen flow meter (29), a hydrogen inlet valve (30), a proportional valve (32), a double ejector (33), a safety valve (34), a steam-water separator (37), a nitrogen exhaust valve (38) and a water exhaust solenoid valve (39); The air circuit includes an air filter (14), an air compressor (17), an intercooler (18) and a humidifier (20); the water circuit includes a cooling fan (1), an expansion water tank (2), a water pump (5), a PTC (6), a three-way valve (7) and a particle filter (8); The water outlet of the battery stack (4) is connected to the water pump (5), the cooling fan (1), the three-way valve (7) and the particle filter (8) in sequence, and the particle filter (8) is connected to the water inlet of the battery stack (4); the water pump (5) is also connected to the PTC (6) and the three-way valve (7) through a pipeline; an expansion water tank (2) is connected to the pipeline between the battery stack (4) and the water pump (5), and the exhaust port of the expansion water tank (2) is also connected to the cooling fan (1); In the air path, the air filter (14) is connected in sequence with the air compressor (17), the intercooler (18) and the humidifier (20); the humidifier (20) is divided into two pipelines and connected to the stack air inlet and stack air outlet interfaces of the stack (4); The intercooler (18) is also connected to the stack air inlet interface of the stack (4) through a pipeline; in the hydrogen path, the nitrogen flow meter (29), the hydrogen inlet valve (30), the proportional valve (32), the double ejector (33), and the safety valve (34) are connected to the stack (4) in sequence; the hydrogen return port of the double ejector (33) is connected to the steam-water separator (37) through a pipeline; the safety valve (34) is also connected to the nitrogen exhaust valve (38) and the steam-water separator (37) in sequence; The air wet side outlet of the humidifier (20) intersects with the liquid outlet of the steam-water separator (37) at a mixing point (27) through a pipeline, and a drainage solenoid valve (39) is provided on the pipeline between the steam-water separator (37) and the mixing point (27); A DCDC controller (3) is also provided on the high voltage output line of the battery stack 4.

2. The device according to claim 1, characterized in that: The mixing point (27) is connected to the muffler (28) and then emptied; The safety valve (34) is also connected to the mixing point (27) through a pipeline; the stack air outlet of the stack (4) is connected to the mixing point (27), and a one-way valve (26) is provided on the pipeline between the stack (4) and the mixing point (27).

3. The device according to claim 1, characterized in that: A flow meter (16) is also provided on the pipeline between the air compressor (17) and the air filter (14); the air compressor (17) is connected to an air compressor controller (13).

4. The device according to claim 1, characterized in that: The particle filter (8) is also connected to a liquid flow meter (12) and an intercooler (18) through pipelines; the intercooler (18) is connected to the water pump (5); the intercooler (18) is also connected to a bypass valve (22) and a battery stack (4) in sequence.

5. The device according to claim 1, characterized in that: A radiator outlet temperature sensor (9) is provided on the outlet pipe of the cooling fan (1); a stack water inlet temperature sensor (11) is provided at the stack water inlet of the stack (4); a stack water outlet temperature sensor (10) is provided at the outlet of the stack (4); and a stack air inlet pressure sensor (24) is provided at the air inlet of the stack (4).

6. The device according to claim 1, characterized in that: A system air inlet pressure sensor (15) is arranged on the pipeline between the air filter (14) and the flow meter (16); a stack air inlet temperature sensor (23) is arranged at the air inlet of the stack (4); a hydrogen medium-pressure pressure sensor (31) is arranged on the pipeline between the hydrogen inlet valve (30) and the proportional valve (32); a hydrogen low-pressure pressure sensor (35) is arranged at the stack hydrogen inlet of the stack; and a hydrogen outlet pressure sensor (36) is arranged at the hydrogen outlet of the stack.

7. A control method for reducing power when a fuel cell system fails, characterized in that: The steps include: (1) Power on the fuel cell system, wake up the fuel cell controller, activate the fuel cell system fault real-time monitoring module, and perform self-check on the fuel cell system. The fault monitoring module receives signals from various electrical devices in real time to determine whether any electrical device is in an abnormal working state. Multiple system operating parameters are used as input conditions for the real-time fault monitoring module. (2) The fuel cell fault real-time monitoring module compares the numerical value input by each electrical device with the fault threshold set by the monitoring module. When a fault is triggered, it determines the level of power reduction fault or serious shutdown fault, and releases the fault information to the upper-level control device so that the upper-level control device can take corresponding actions; the upper-level control device includes a car, a ship, a drone, a fixed power station or a backup power supply; (3) The fuel cell system fault monitoring module determines that a power reduction level 1 fault has occurred, and at the same time determines the difference between the required power P1 given by the upper level control device and the power threshold P3 set at the power reduction level 1 as the current first power P2 that the current fuel cell system needs to respond to; (4) Because the fuel cell system has idle power, it is to prevent the fuel cell from running at a high potential for a long time and causing carbon corrosion, thereby causing the life of the fuel cell system to decay rapidly. Therefore, it is necessary to determine whether the current first power P2 is less than or equal to the idle power P5. If it is less, the idle power P5 is output in response; if it is greater, the current first power P2 is maintained and the power input is used as the stack load current value under the fuel cell system fault state, reducing and limiting the air and hydrogen intake and drainage frequency, and at the same time transmitting the fault information to the upper level control device as "Fuel system XXX fault, power reduction mode one level"; (5) Since the power value of the fuel cell is distributed according to the electric density point, the power generally has a large range. In order to distinguish whether the fault is serious, two levels of power reduction are set. The first level of power reduction is to reduce the existing power by (20-30)% as the fault limit output power, and the second level of power reduction is to reduce the existing power by (50-70)% as the fault limit output power. When the fuel cell system fault monitoring module determines that it has entered the second level of power reduction fault, it also determines the difference between the required power P1 given by the upper level control device and the power threshold P6 set for the second level of power reduction as the current second power P4 that the current fuel cell system needs to respond to; it determines whether the current second power P4 is less than or equal to the idle power P5. If it is less than, the idle power P5 is output to respond; if it is greater than, the current second power P4 is maintained to respond. This power input is used as the stack load current value under the fault state of the fuel cell system, and the air and hydrogen intake and drainage frequency are rapidly reduced and limited. At the same time, the fault information is transmitted to the upper level control device as "Fuel system XXX fault, power reduction second level mode"; (6) The fuel cell system fault monitoring module determines that it has entered a serious level 3 fault, and the fault holding time must be greater than or equal to the fault time T2. After it is determined to be a real verification fault, the fault information is transmitted to the upper-level control device as "Fuel system XXX fault, serious fault, system shutdown". At the same time, the fuel cell system fails and shuts down, and the upper-level device needs to switch to pure electric mode and continue to drive in pure electric mode; (7) When the fuel cell system is in a power reduction level 1 or 2 fault state, the system determines the delay T1 to allow the fault detection module to detect the system state in real time. For example, when one or more parameters are restored to within the fault threshold, it can be determined that the system has not triggered a fault and returns to normal mode from the original power reduction mode, thereby responding to the power demand P1 given by the upper-level control device and canceling the fault information transmitted to the outside. At this time, the fuel cell system needs to increase the intake of hydrogen and air first, and then increase the current value of the fuel cell stack to meet the power demand P1. If in the case of a power reduction level 2 fault, one or more parameters are restored to within the power reduction level 1 fault threshold, it can be determined that the fuel cell system has returned to the power reduction level 1 state, and the current second power P4 becomes the current first power P2. The fuel cell system can increase the intake of hydrogen and air and increase the current value of the fuel cell stack to meet the current first power P2.

8. The control method for reducing power when a fuel cell system fails according to claim 7, characterized in that: When the fuel cell system is judging the status of the entire system, whether it is a fault state or a non-fault state, the corresponding system power emitted needs to re-judge the status of the fuel cell system within the delay time T1, and continuously cycle the entire judgment logic to achieve the real-time performance of the fuel cell fault monitoring module. The corresponding operation needs to be executed in the corresponding state.

9. The control method for reducing power when a fuel cell system fails according to claim 7, characterized in that: According to different faults and fault severity, the corresponding first-level power reduction P2 and second-level power reduction P4 need to be obtained after further bench test calibration; the delay time T1 of the entire fault real-time monitoring module also needs to be obtained through calibration according to different fault responses.

10. The control method for reducing power when a fuel cell system fails according to claim 7, characterized in that: When the fuel cell system switches from the power reduction mode to the normal mode, when the power increases, it is necessary to first increase the intake of hydrogen and air, and then load the current at a load slope of (30-50) A / s to meet the power demand P1 given by the upper-level control device; when the fuel cell system switches from the normal mode to the power reduction level one or two, when the power decreases, it is necessary to first quickly reduce the current at a load reduction slope of (45-60) A / s to prevent shutdown caused by rapid deviation of operating parameters at high power to the fault threshold set by the severe level three fault mode. At this time, the intake of air and hydrogen is rapidly reduced to achieve the purpose of rapid load reduction to stabilize the fuel cell system parameters and gradually restore to normal state, thereby ensuring the stability and reliability of the system.

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