Fuel cell system fault diagnosis method and system

Abstract

The invention provides a fuel cell system fault diagnosis method and system, and the method comprises the steps: obtaining the operation data of a fuel cell system at different environment temperatures, calibrating the minimum value of the pressure of hydrogen entering the system, the maximum deviation value of the pressure of hydrogen entering a galvanic pile, and the minimum value of the opening degree of a proportional valve; detecting the pressure value change of hydrogen entering the system, the pressure value change of hydrogen entering a galvanic pile and the opening degree of a proportional valve of the fuel cell system in real time, and performing diagnostic analysis to obtain a corresponding fault diagnosis result; and when the corresponding fault diagnosis result simultaneously meets the corresponding preset diagnosis requirement and maintains a preset time length, determining the fault of the fuel cell system. According to the invention, the problem of poor fault diagnosis reliability caused by the fact that fault problems such as too low voltage and the like cannot be effectively and timely diagnosed because the fault diagnosis of the drain valve is mostly diagnosed through single-chip voltage in the prior art is solved. According to the invention, multi-line parallel fault diagnosis of the fuel cell system is realized, and the fault diagnosis reliability is improved.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell fault diagnosis, and in particular to a fuel cell system fault diagnosis method and system. Background Art

[0002] As a key component for regulating water balance in the fuel cell system, the steam trap plays an irreplaceable role. It can intelligently remove the condensed water accumulated in the system and prevent the membrane electrode flooding caused by excessive water accumulation, thereby ensuring the normal operation of the fuel cell. In addition, the steam trap also effectively limits the excessive accumulation of nitrogen permeation on the cathode side through periodic discharge operations, thereby preventing the negative impact of excessive nitrogen content on the reaction efficiency of the fuel cell. Therefore, how to solve the problem of steam trap failure or blockage of its rear-end pipeline has become the current technical key.

[0003] At present, the existing technology mostly uses parameters such as stack impedance and single-chip voltage for diagnosis. This method is too complicated. If the diagnosis is performed through the single-chip voltage, the low voltage proves that the system has already entered the steam trap fault state. The fault diagnosis time is too long. Long-term lack of hydrogen will cause irreversible damage to the system and damage its life. In addition, there is no good solution to the pipeline blockage problem caused by winter conditions. Therefore, the existing technology cannot effectively and timely diagnose fault problems such as low voltage, resulting in poor reliability of fault diagnosis. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a fuel cell system fault diagnosis method and system to realize multi-line parallel fault diagnosis of the fuel cell system and improve the reliability of fault diagnosis.

[0005] To achieve the above object, an embodiment of the present invention provides a fuel cell system fault diagnosis method, comprising:

[0006] Based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located, obtaining the operating data of the fuel cell system under different ambient temperatures;

[0007] Based on the fuel cell system operation data at the different ambient temperatures, calibrate the minimum value of hydrogen inlet pressure, the maximum value of hydrogen inlet pressure deviation, and the minimum value of proportional valve opening;

[0008] Based on the minimum value of the hydrogen inlet system pressure, the maximum value of the hydrogen inlet stack pressure deviation and the minimum value of the proportional valve opening, the changes in the hydrogen inlet system pressure value, the changes in the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system are detected in real time, and diagnostic analysis is performed to obtain corresponding fault diagnosis results;

[0009] When the corresponding fault diagnosis result simultaneously satisfies the corresponding preset diagnosis requirement and is maintained for a preset time length, a fuel cell system fault is determined.

[0010] Furthermore, the obtaining of the fuel cell system operation data at different ambient temperatures based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located includes:

[0011] Based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located, the temperature range is divided into a number of equidistant temperature intervals;

[0012] At each temperature interval, all current density points are pulled to the rated operating conditions by the fuel cell system to obtain the operating data of the fuel cell system under different ambient temperatures.

[0013] Furthermore, based on the fuel cell system operation data at different ambient temperatures, the minimum value of hydrogen inlet pressure, the maximum value of hydrogen inlet pressure deviation and the minimum value of proportional valve opening are calibrated, including:

[0014] Constructing a fuel cell system operation data table based on the fuel cell system operation data at the different ambient temperatures;

[0015] Based on the fuel cell system operation data table, by linear table lookup, obtain the pressure reduction value of hydrogen entering the system when the steam trap is opened, the pressure increase value of hydrogen entering the fuel cell stack when the steam trap is opened, and the reduction value of the proportional valve opening when the steam trap is opened;

[0016] Based on the hydrogen inlet system pressure reduction value when the steam trap is opened, the minimum value of the hydrogen inlet system pressure drop relative to the steady-state pressure is calibrated as the minimum hydrogen inlet system pressure value;

[0017] Based on the increase value of the hydrogen inlet stack pressure when the steam trap is opened, calibrating the maximum value of the hydrogen inlet stack pressure deviation relative to the target pressure as the maximum value of the hydrogen inlet stack pressure deviation;

[0018] Based on the decrease value of the proportional valve opening when the steam trap is opened, the minimum value of the proportional valve opening change relative to the target opening is calibrated as the minimum proportional valve opening value.

[0019] Furthermore, based on the minimum value of the hydrogen inlet pressure, the maximum value of the hydrogen inlet pressure deviation and the minimum value of the proportional valve opening, the changes in the hydrogen inlet pressure value, the hydrogen inlet pressure value and the proportional valve opening of the fuel cell system are detected in real time, and diagnostic analysis is performed to obtain corresponding fault diagnosis results, including:

[0020] Based on the system opening instruction and the steam trap opening instruction, detecting whether the change in the pressure value of hydrogen entering the system is less than the minimum value of the hydrogen entering the system pressure, and obtaining a first fault diagnosis result;

[0021] Based on the system start-up instruction, detecting whether the change in the pressure value of hydrogen entering the fuel cell stack is greater than the maximum value of the pressure deviation of hydrogen entering the fuel cell stack, and obtaining a second fault diagnosis result;

[0022] Based on the system opening instruction, it is detected whether the opening size of the proportional valve is less than the minimum opening size of the proportional valve to obtain a third fault diagnosis result.

[0023] Further, when the corresponding fault diagnosis result simultaneously meets the corresponding preset diagnosis requirement and maintains the preset time length, determining that the fuel cell system is faulty includes:

[0024] When the first fault diagnosis result is that the change in the hydrogen inlet system pressure value is detected to be less than the minimum value of the hydrogen inlet system pressure, a first fault warning result is obtained;

[0025] When the second fault diagnosis result is that the change in the hydrogen inlet pressure value is greater than the maximum value of the hydrogen inlet pressure deviation, a second fault warning result is obtained;

[0026] When the third fault diagnosis result is that the opening of the proportional valve is smaller than the minimum opening of the proportional valve, a third fault warning result is obtained;

[0027] When the first fault warning result, the second fault warning result and the third fault warning result exist simultaneously and are maintained for a preset time length, it is determined that the fuel cell system is faulty.

[0028] Furthermore, it also includes:

[0029] Based on the fuel cell system operation data at the different ambient temperatures, calibrate the minimum change value of the hydrogen inlet pressure;

[0030] Based on the minimum value of the hydrogen inlet system pressure, the minimum value of the hydrogen inlet stack pressure change and the minimum value of the proportional valve opening, the changes in the hydrogen inlet system pressure value, the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system are detected in real time, and diagnostic analysis is performed to obtain corresponding fault diagnosis results.

[0031] Furthermore, based on the fuel cell system operation data at different ambient temperatures, the minimum change value of the hydrogen inlet pressure is calibrated, including:

[0032] Based on the fuel cell system operation data table, a change value of the hydrogen inlet stack pressure when the steam trap is opened is obtained by linear table lookup;

[0033] Based on the change value of the hydrogen inlet stack pressure when the steam trap is opened, the minimum value of the hydrogen inlet stack pressure drop relative to the steady-state pressure is calibrated as the minimum value of the hydrogen inlet stack pressure change.

[0034] Furthermore, based on the minimum value of the hydrogen inlet pressure, the minimum value of the hydrogen inlet pressure change and the minimum value of the proportional valve opening, the changes in the hydrogen inlet pressure value, the hydrogen inlet pressure value and the proportional valve opening of the fuel cell system are detected in real time, and diagnostic analysis is performed to obtain corresponding fault diagnosis results, including:

[0035] Based on the system opening instruction and the steam trap opening instruction, detecting whether the change in the pressure value of hydrogen entering the system is less than the minimum value of the hydrogen entering the system pressure, and obtaining a fourth fault diagnosis result;

[0036] Based on the system opening instruction and the steam trap opening instruction, detecting whether the change in the pressure value of hydrogen entering the fuel cell stack is greater than the minimum value of the pressure change of hydrogen entering the fuel cell stack, and obtaining a fifth fault diagnosis result;

[0037] Based on the system opening instruction and the steam trap opening instruction, it is detected whether the opening degree of the proportional valve is less than the minimum opening degree of the proportional valve, and a sixth fault diagnosis result is obtained.

[0038] The embodiment of the present invention also provides a fuel cell system fault diagnosis system, comprising: an operation data acquisition module, a threshold calibration module, a diagnosis analysis module and a fault detection module;

[0039] The operation data acquisition module is used to acquire the operation data of the fuel cell system under different ambient temperatures based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located;

[0040] The threshold calibration module is used to calibrate the minimum value of hydrogen inlet pressure, the maximum value of hydrogen inlet pressure deviation and the minimum value of proportional valve opening based on the fuel cell system operation data under different ambient temperatures;

[0041] The diagnostic analysis module is used to detect the changes in the hydrogen inlet system pressure value, the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system in real time based on the minimum value of the hydrogen inlet system pressure, the maximum value of the hydrogen inlet stack pressure deviation and the minimum value of the proportional valve opening, and perform diagnostic analysis to obtain corresponding fault diagnosis results;

[0042] The fault detection module is used to determine that the fuel cell system is faulty when the corresponding fault diagnosis result simultaneously meets the corresponding preset diagnosis requirement and is maintained for a preset time length.

[0043] Furthermore, the operation data acquisition module is used to acquire the operation data of the fuel cell system under different ambient temperatures based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located, including:

[0044] Temperature range division unit and system operation test unit;

[0045] The temperature interval division unit is used to divide the temperature interval into a number of equidistant temperature intervals based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located;

[0046] The system operation test unit is used to load all current density points to the rated operating conditions through the fuel cell system at each temperature interval point, so as to obtain the fuel cell system operation data under different ambient temperatures.

[0047] Furthermore, the threshold calibration module is used to calibrate the minimum value of hydrogen inlet pressure, the maximum value of hydrogen inlet pressure deviation and the minimum value of proportional valve opening based on the fuel cell system operation data at different ambient temperatures, including:

[0048] A data table building unit, a threshold query unit, a first calibration unit, a second calibration unit and a third calibration unit;

[0049] The data table building unit is used to build a fuel cell system operation data table based on the fuel cell system operation data at different ambient temperatures;

[0050] The threshold query unit is used to obtain, based on the fuel cell system operation data table, a pressure reduction value of hydrogen entering the system when the steam trap is opened, a pressure increase value of hydrogen entering the fuel cell stack when the steam trap is opened, and a reduction value of the proportional valve opening when the steam trap is opened by linear table lookup;

[0051] The first calibration unit is used to calibrate the minimum value of the hydrogen inlet system pressure drop relative to the steady-state pressure as the minimum value of the hydrogen inlet system pressure based on the hydrogen inlet system pressure reduction value when the steam trap is opened;

[0052] The second calibration unit is used to calibrate the maximum value of the hydrogen inlet stack pressure value deviation from the target pressure as the maximum value of the hydrogen inlet stack pressure deviation based on the increase value of the hydrogen inlet stack pressure when the steam trap is opened;

[0053] The third calibration unit is used to calibrate the minimum value of the proportional valve opening change relative to the target opening as the minimum proportional valve opening value based on the decrease value of the proportional valve opening when the steam trap is opened.

[0054] Furthermore, the diagnostic analysis module is used to detect the change of the hydrogen inlet system pressure value, the change of the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system in real time based on the minimum value of the hydrogen inlet system pressure, the maximum value of the hydrogen inlet stack pressure deviation and the minimum value of the proportional valve opening, and perform diagnostic analysis to obtain the corresponding fault diagnosis results, including:

[0055] a first diagnostic unit, a second diagnostic unit, and a third diagnostic unit;

[0056] The first diagnostic unit is used to detect whether the change in the pressure value of hydrogen entering the system is less than the minimum value of the pressure of hydrogen entering the system based on the system opening instruction and the steam trap opening instruction, and obtain a first fault diagnosis result;

[0057] The second diagnostic unit is used to detect whether the change of the hydrogen inlet pressure value is greater than the maximum value of the hydrogen inlet pressure deviation based on the system start-up instruction, and obtain a second fault diagnosis result;

[0058] The third diagnostic unit is used to detect whether the opening size of the proportional valve is less than the minimum opening size of the proportional valve based on the system opening instruction, and obtain a third fault diagnosis result.

[0059] Furthermore, the fault detection module is used to determine the fuel cell system fault when the corresponding fault diagnosis result simultaneously meets the corresponding preset diagnosis requirement and maintains the preset time length, including:

[0060] a first fault warning unit, a second fault warning unit, a third fault warning unit and a fault determination unit;

[0061] The first fault warning unit is used to obtain a first fault warning result when the first fault diagnosis result is that the change in the hydrogen inlet system pressure value is detected to be less than the minimum value of the hydrogen inlet system pressure;

[0062] The second fault warning unit is used to obtain a second fault warning result when the second fault diagnosis result is that the change in the hydrogen inlet pressure value is greater than the maximum value of the hydrogen inlet pressure deviation;

[0063] The third fault warning unit is used to obtain a third fault warning result when the third fault diagnosis result is that the opening of the proportional valve is smaller than the minimum opening of the proportional valve;

[0064] The fault determination unit is used to determine a fuel cell system fault when the first fault warning result, the second fault warning result and the third fault warning result exist simultaneously and are maintained for a preset time length.

[0065] Beneficial effects:

[0066] By utilizing the system operation data for threshold calibration, only the existing parameters of the system itself are collected and detected without adding other additional sensor devices. The fuel cell system controller analyzes the operating status information fed back by the system to quickly determine the fault. In addition, through multiple branch fault detection, and considering the detection results of multiple branches during fault diagnosis to determine whether there is a system fault, false fault alarms caused by errors in information collection by some devices are avoided, thereby improving the reliability of battery fuel system fault diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 A schematic flow chart of the steps of a fuel cell system fault diagnosis method provided by an embodiment of the present invention;

[0068] Figure 2 A fuel cell system framework for application of a fuel cell system fault diagnosis method provided in one embodiment of the present invention;

[0069] Figure 3 A schematic diagram of a multi-path fault detection process of a fuel cell system fault diagnosis method provided in an embodiment of the present invention Figure 1 ;

[0070] Figure 4 A schematic diagram of a multi-path fault detection process of a fuel cell system fault diagnosis method provided in an embodiment of the present invention Figure 2 ;

[0071] Figure 5 A schematic diagram of a fault judgment timing of a fuel cell system fault diagnosis method provided by an embodiment of the present invention;

[0072] Figure 6 A schematic diagram of the module structure of a fuel cell system fault diagnosis system provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0073] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0074] Example 1

[0075] See also Figure 1 , Figure 1 A schematic flow chart of a fuel cell system fault diagnosis method provided by an embodiment of the present invention. Figure 1 As shown, the embodiment of the present invention provides a fuel cell system fault diagnosis method, including steps 101 to 104; see Figure 2 , Figure 2 A fuel cell system framework for application of a fuel cell system fault diagnosis method provided by a certain embodiment of the present invention; Figure 2 As shown, in the embodiment of the present invention, the following Figure 2 The fuel cell system framework shown explains a fuel cell system fault diagnosis method proposed in an embodiment of the present invention, which will not be described in detail below.

[0076] An embodiment of the present invention provides a method for diagnosing a fuel cell system fault, and the steps are as follows:

[0077] Step 101, based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located, obtaining the operating data of the fuel cell system under different ambient temperatures;

[0078] As an example of this embodiment, based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located, the temperature range is divided into several equidistant temperature intervals; at each temperature interval point, all current density points are pulled to the rated operating conditions by the fuel cell system to obtain the operating data of the fuel cell system at different ambient temperatures. A specific implementation method is to run the system and set the system at different ambient temperatures, such as a set of tests at intervals of 10°C (relative to the equidistant temperature intervals) from -30 to 40°C (relative to the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located), and the system pulls all current density points (the current size per unit area) to the rated operating conditions to obtain system operating data of 8 data points from -30 to 40°C.

[0079] Step 102, based on the fuel cell system operation data at different ambient temperatures, calibrate the minimum value of hydrogen inlet pressure, the maximum value of hydrogen inlet pressure deviation, and the minimum value of proportional valve opening;

[0080] As an example of this embodiment, based on the fuel cell system operation data under the different ambient temperatures, a fuel cell system operation data table is constructed; based on the fuel cell system operation data table, a pressure reduction value of hydrogen entering the system when the drain valve is opened, an increase value of hydrogen entering the stack pressure when the drain valve is opened, and a decrease value of the proportional valve opening when the drain valve is opened are obtained through linear table lookup; based on the pressure reduction value of hydrogen entering the system when the drain valve is opened, the minimum value of the hydrogen entering the system pressure drop relative to the steady-state pressure is calibrated as the minimum value of the hydrogen entering the system pressure; based on the pressure increase value of hydrogen entering the stack when the drain valve is opened, the maximum value of the hydrogen entering the stack pressure deviation relative to the target pressure is calibrated as the maximum value of the hydrogen entering the stack pressure deviation; based on the decrease value of the proportional valve opening when the drain valve is opened, the minimum value of the proportional valve opening change relative to the target opening is calibrated as the minimum value of the proportional valve opening. A specific implementation method is to create a fuel cell system operation data table containing fields such as temperature T, P_drop(T), P_increase(T), Open_drop(T), P_min(T), P_max(T) and Open_min(T), and fill the experimental data at each temperature point into the table to obtain the fuel cell system operation data table; use linear interpolation or linear table lookup method to find the corresponding P_drop(T), P_increase(T) and Open_drop(T) values ​​in the fuel cell system operation data table according to the current temperature T, and then calibrate P_min(T), P_max(T) and Open_min(T). The specific method for obtaining and calibrating the data after the table is created is as follows: at each temperature point (-30℃ to 40℃ , one group every 10℃), when the steam trap is opened, record the decrease value P_drop(T) of the hydrogen inlet system pressure relative to the steady-state pressure, where T represents temperature. Based on the decrease value of the hydrogen inlet system pressure when the steam trap is opened, calibrate the minimum value of the hydrogen inlet system pressure drop relative to the steady-state pressure as the minimum value P_min(T) of the hydrogen inlet system pressure; when the steam trap is opened, record the increase value P_increase(T) of the hydrogen inlet stack pressure relative to the steady-state pressure, and calibrate the maximum value of the hydrogen inlet stack pressure deviation relative to the target pressure as the maximum value P_max(T) of the hydrogen inlet stack pressure deviation; when the steam trap is opened, record the decrease value Open_drop(T) of the proportional valve opening, and calibrate the minimum value of the proportional valve opening change relative to the target opening as the minimum value Open_min(T) of the proportional valve opening.

[0081] Step 103, based on the minimum value of the hydrogen inlet system pressure, the maximum value of the hydrogen inlet stack pressure deviation and the minimum value of the proportional valve opening, real-time detection of the change of the hydrogen inlet system pressure value, the change of the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system, and diagnosis and analysis are performed to obtain corresponding fault diagnosis results;

[0082] As an example of this embodiment, based on the system opening instruction and the steam trap opening instruction, detect whether the change in the pressure value of hydrogen entering the system is less than the minimum value of the hydrogen entering the system pressure, and obtain the first fault diagnosis result; based on the system opening instruction, detect whether the change in the pressure value of hydrogen entering the fuel cell is greater than the maximum value of the hydrogen entering the fuel cell pressure deviation, and obtain the second fault diagnosis result; based on the system opening instruction, detect whether the opening size of the proportional valve is less than the minimum opening size of the proportional valve, and obtain the third fault diagnosis result. For a specific possible implementation method, see Figure 3 , Figure 3 A schematic diagram of a multi-path fault detection flow of a fuel cell system fault diagnosis method provided for an embodiment of the present invention; the diagnostic algorithm has three diagnostic branches (B1, B2 and B3), one of which is to determine the pressure change of hydrogen entering the system, one of which is to determine the deviation of the pressure of hydrogen entering the fuel cell stack from the target value and the other is to determine the opening size of the proportional valve; first, the steam trap switch instruction is obtained (the instruction is generally issued by the controller algorithm when the volume of condensed water produced by the reaction of the hydrogen subsystem reaches a certain value), and when the steam trap is determined to be open, branch B1 starts to detect the pressure change of hydrogen entering the system to determine whether the pressure fluctuation is less than the calibration value P_min(T) (linear table lookup is performed according to the current ambient temperature, different temperatures Corresponding to a value), if this branch is satisfied, the first fault diagnosis result is obtained. If the condition cannot be met during the judgment process, the judgment needs to be restarted when the steam trap is closed; after the startup is completed, branch B2 starts to detect whether the hydrogen inlet stack pressure value exceeds the target value. If the deviation from the target value is greater than P_max(T) (linear table lookup based on the current ambient temperature, different temperatures correspond to a value), then the condition branch is satisfied, and the second fault diagnosis result is obtained; after the startup is completed, branch B3 starts to detect the opening size of the proportional valve. When it is determined that the opening is less than the current calibration value Open_Min(T) (linear table lookup based on the current ambient temperature, different temperatures correspond to a value), it is determined that the condition is satisfied, and the third fault diagnosis result is obtained.

[0083] As another example of this embodiment, based on the fuel cell system operation data under the different ambient temperatures, the minimum value of the hydrogen inlet pressure change is calibrated; based on the minimum value of the hydrogen inlet pressure, the minimum value of the hydrogen inlet pressure change and the minimum value of the proportional valve opening, the changes in the hydrogen inlet pressure value, the hydrogen inlet pressure value and the proportional valve opening of the fuel cell system are detected in real time, and diagnostic analysis is performed to obtain the corresponding fault diagnosis results. Based on the fuel cell system operation data table, the change value of the hydrogen inlet pressure when the steam trap is opened is obtained through linear table lookup; based on the change value of the hydrogen inlet pressure when the steam trap is opened, the minimum value of the hydrogen inlet pressure drop relative to the steady-state pressure is calibrated as the minimum value of the hydrogen inlet pressure change. Based on the system opening instruction and the steam trap opening instruction, detect whether the change in the pressure value of hydrogen entering the system is less than the minimum value of the hydrogen entering the system pressure, and obtain the fourth fault diagnosis result; based on the system opening instruction and the steam trap opening instruction, detect whether the change in the pressure value of hydrogen entering the fuel cell is greater than the minimum value of the hydrogen entering the fuel cell pressure change, and obtain the fifth fault diagnosis result; based on the system opening instruction and the steam trap opening instruction, detect whether the opening size of the proportional valve is less than the minimum opening size of the proportional valve, and obtain the sixth fault diagnosis result. For a specific implementation method, see Figure 4 , Figure 4 A schematic diagram of a multi-path fault detection process of a fuel cell system fault diagnosis method provided in an embodiment of the present invention Figure 2; Use linear interpolation or linear table lookup to find the corresponding hydrogen inlet stack pressure value relative to the steady-state pressure drop value P_CELL_drop(T) in the fuel cell system operation data table according to the current temperature T, and then calibrate the minimum value of the hydrogen inlet stack pressure change P_CELL_min(T). The specific implementable method is as follows: At each temperature point (-30℃ to 40℃, one group every 10℃), when the steam trap is opened, record the hydrogen inlet stack pressure value relative to the steady-state pressure drop value P_ CELL_drop(T), and then, the minimum value of the hydrogen inlet pressure relative to the steady-state pressure drop value is calibrated as the minimum value of the hydrogen inlet pressure change P_CELL_min(T). Then, three diagnostic branches (B1, B4 and B3) are used for fault diagnosis. One of them is to judge the change of hydrogen inlet pressure, one is to judge the change of hydrogen inlet pressure and the other is to judge the opening size of the proportional valve. When the startup is completed and when the steam trap is judged to be open, the fault is diagnosed. Branch B1 starts to detect the change of hydrogen entering the system pressure, and determines whether the pressure fluctuation is less than the calibration value P_min(T) (linear table lookup is performed according to the current ambient temperature, and different temperatures correspond to a value). If this branch satisfies the condition, the fourth fault diagnosis result is obtained; after the startup is completed and when the steam trap is determined to be open, branch B4 starts to detect the change of hydrogen entering the stack pressure, and determines whether the change of hydrogen entering the stack pressure value is greater than the minimum value of hydrogen entering the stack pressure change P_CELL_min(T). If this branch satisfies the condition, the fifth fault diagnosis result is obtained; after the startup is completed and when the steam trap is determined to be open, branch B3 starts to detect the opening size of the proportional valve, and when the opening is determined to be less than the current calibration value Open_Min(T) (linear table lookup is performed according to the current ambient temperature, and different temperatures correspond to a value), it is determined that the condition is satisfied, and the sixth fault diagnosis result is obtained; it is worth mentioning that if branches B1, B4 and B3 do not detect that the switch instruction of the steam trap is open, the steam trap is closed, and the system fault is re-determined after the steam trap is opened. The diagnostic branches B1, B4 and B3 described in this embodiment are an optimization compared to the scheme where the diagnostic branches are B1, B2 and B3. By setting the switch instructions of the steam trap as the prerequisites for the fault diagnosis of the three branches, and then replacing branch B2 with branch B4, the principle of fault diagnosis remains unchanged, only the diagnostic conditions are changed.

[0084] Step 104 : When the corresponding fault diagnosis result satisfies the corresponding preset diagnosis requirement and maintains the preset time length, it is determined that the fuel cell system is faulty.

[0085] As an example of this embodiment, when the first fault diagnosis result is that the change in the hydrogen inlet pressure value is less than the minimum value of the hydrogen inlet pressure, a first fault warning result is obtained; when the second fault diagnosis result is that the change in the hydrogen inlet pressure value is greater than the maximum value of the hydrogen inlet pressure deviation, a second fault warning result is obtained; when the third fault diagnosis result is that the proportional valve opening is less than the minimum value of the proportional valve opening, a third fault warning result is obtained; when the first fault warning result, the second fault warning result and the third fault warning result exist at the same time and are maintained for a preset time length, a fuel cell system fault is determined. For a specific possible implementation method, see Figure 5 , Figure 5 A schematic diagram of a fault judgment timing of a fuel cell system fault diagnosis method provided by an embodiment of the present invention; Figure 5 As shown, when the three diagnostic branches meet their respective corresponding requirements at the same time, and the fault time exceeds the predetermined time at the same time, it is determined that a fault occurs, that is, when branches B1, B2 and B3 all meet the conditions at the same time, and the maintenance time exceeds ts, it is determined that a fault occurs, wherein the time t is to operate the system at different ambient temperatures (from -30 to 40°C, with a group of tests at intervals of 10°C), the test blocks the rear end pipeline of the steam trap, and optimizes the time calibration t; it is worth mentioning that in another embodiment, when branches B1, B4 and B3 all meet the conditions at the same time, and the maintenance time exceeds ts, it is also determined that a fault occurs.

[0086] A fuel cell system fault diagnosis method proposed in an embodiment of the present invention performs threshold calibration by utilizing system operation data. It only collects and detects parameters existing in the system itself without adding other sensor devices. The fuel cell system controller analyzes the operation status information fed back by the system to quickly determine the fault. In addition, multiple branches are detected for faults, and the detection results of multiple branches are considered during fault diagnosis to determine whether the system has a fault, thereby avoiding false fault alarms caused by errors in information collection by some devices, thereby improving the reliability of battery fuel system fault diagnosis.

[0087] Example 2

[0088] See also Figure 6 , Figure 6 A schematic diagram of the module structure of a fuel cell system fault diagnosis system provided by an embodiment of the present invention; Figure 6 As shown, the embodiment of the present invention provides a fuel cell system fault diagnosis system, including: an operation data acquisition module 501, a threshold calibration module 502, a diagnosis analysis module 503 and a fault detection module 504;

[0089] The operation data acquisition module 501 is used to acquire the operation data of the fuel cell system under different ambient temperatures based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located;

[0090] As an example of this embodiment, the operation data acquisition module 501 is used to acquire the operation data of the fuel cell system under different ambient temperatures based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located, including:

[0091] Temperature interval division unit 601 and system operation test unit 602;

[0092] The temperature interval division unit 601 is used to divide the temperature interval into a number of equidistant temperature intervals based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located; the system operation test unit 602 is used to pull all current density points to the rated operating conditions through the fuel cell system at the interval point of each temperature interval to obtain the fuel cell system operation data under different ambient temperatures.

[0093] The threshold calibration module 502 is used to calibrate the minimum value of hydrogen inlet pressure, the maximum value of hydrogen inlet pressure deviation and the minimum value of proportional valve opening based on the fuel cell system operation data under different ambient temperatures;

[0094] As an example of this embodiment, the threshold calibration module 502 is used to calibrate the minimum value of the hydrogen inlet system pressure, the maximum value of the hydrogen inlet stack pressure deviation and the minimum value of the proportional valve opening based on the fuel cell system operation data at different ambient temperatures, including:

[0095] Data table building unit 701, threshold query unit 702, first calibration unit 703, second calibration unit 704 and third calibration unit 705;

[0096] The data table building unit 701 is used to build a fuel cell system operation data table based on the fuel cell system operation data under different ambient temperatures;

[0097] The threshold query unit 702 is used to obtain, based on the fuel cell system operation data table, a pressure reduction value of hydrogen entering the system when the steam trap is opened, a pressure increase value of hydrogen entering the fuel cell stack when the steam trap is opened, and a reduction value of the proportional valve opening when the steam trap is opened by linear table lookup;

[0098] The first calibration unit 703 is used to calibrate the minimum value of the hydrogen inlet system pressure drop relative to the steady-state pressure as the minimum value of the hydrogen inlet system pressure based on the hydrogen inlet system pressure reduction value when the steam trap is opened;

[0099] The second calibration unit 704 is used to calibrate the maximum value of the hydrogen inlet stack pressure value deviation from the target pressure as the maximum value of the hydrogen inlet stack pressure deviation based on the increase value of the hydrogen inlet stack pressure when the steam trap is opened;

[0100] The third calibration unit 705 is used to calibrate the minimum value of the proportional valve opening change relative to the target opening as the minimum proportional valve opening value based on the decrease value of the proportional valve opening when the steam trap is opened.

[0101] The diagnostic analysis module 503 is used to detect the change of the hydrogen inlet pressure value, the hydrogen inlet pressure value and the proportional valve opening of the fuel cell system in real time based on the minimum value of the hydrogen inlet pressure, the maximum value of the hydrogen inlet pressure deviation and the minimum value of the proportional valve opening, and perform diagnostic analysis to obtain the corresponding fault diagnosis result;

[0102] As an example of this embodiment, the diagnostic analysis module 503 is used to detect the change of the hydrogen inlet system pressure value, the change of the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system in real time based on the minimum value of the hydrogen inlet system pressure, the maximum value of the hydrogen inlet stack pressure deviation and the minimum value of the proportional valve opening, and perform diagnostic analysis to obtain corresponding fault diagnosis results, including:

[0103] A first diagnostic unit 801, a second diagnostic unit 802 and a third diagnostic unit 803;

[0104] The first diagnostic unit 801 is used to detect whether the change in the pressure value of hydrogen entering the system is less than the minimum value of the pressure of hydrogen entering the system based on the system opening instruction and the steam trap opening instruction, and obtain a first fault diagnosis result;

[0105] The second diagnostic unit 802 is used to detect whether the change of the hydrogen inlet pressure value is greater than the maximum value of the hydrogen inlet pressure deviation based on the system start-up instruction, and obtain a second fault diagnosis result;

[0106] The third diagnosis unit 803 is used to detect whether the opening of the proportional valve is less than the minimum opening of the proportional valve based on the system opening instruction, and obtain a third fault diagnosis result.

[0107] The fault detection module 504 is used to determine that the fuel cell system is faulty when the corresponding fault diagnosis result simultaneously meets the corresponding preset diagnosis requirement and is maintained for a preset time length.

[0108] As an example of this embodiment, the fault detection module 504 is used to determine the fuel cell system fault when the corresponding fault diagnosis result satisfies the corresponding preset diagnosis requirement and maintains the preset time length, including:

[0109] A first fault warning unit 901, a second fault warning unit 902, a third fault warning unit 903 and a fault determination unit 904;

[0110] The first fault warning unit 901 is used to obtain a first fault warning result when the first fault diagnosis result is that the change in the hydrogen inlet system pressure value is detected to be less than the minimum value of the hydrogen inlet system pressure;

[0111] The second fault warning unit 902 is used to obtain a second fault warning result when the second fault diagnosis result is that the change in the hydrogen inlet pressure value is greater than the maximum value of the hydrogen inlet pressure deviation;

[0112] The third fault warning unit 903 is used to obtain a third fault warning result when the third fault diagnosis result is that the opening of the proportional valve is smaller than the minimum opening of the proportional valve;

[0113] The fault determination unit 904 is used to determine that the fuel cell system has a fault when the first fault warning result, the second fault warning result and the third fault warning result exist at the same time and are maintained for a preset time length.

[0114] A fuel cell system fault diagnosis system proposed in an embodiment of the present invention utilizes system operation data to perform threshold calibration through an operation data acquisition module and a threshold calibration module. It only collects and detects parameters existing in the system itself without adding other additional sensor devices. The fuel cell system controller analyzes the operation status information fed back by the system to quickly determine the fault. In addition, multiple branch fault detection is performed through the diagnosis analysis module and the fault detection module, and the detection results of multiple branches are considered during fault diagnosis to determine whether there is a fault in the system, thereby avoiding false fault alarms caused by errors in information collection by some devices, thereby improving the reliability of battery fuel system fault diagnosis.

[0115] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0116] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0117] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

Claims

1. A fuel cell system fault diagnosis method, characterized in that: include: Based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located, obtaining the operating data of the fuel cell system under different ambient temperatures; Based on the fuel cell system operation data at the different ambient temperatures, calibrate the minimum value of hydrogen inlet pressure, the maximum value of hydrogen inlet pressure deviation, and the minimum value of proportional valve opening; Based on the minimum value of the hydrogen inlet system pressure, the maximum value of the hydrogen inlet stack pressure deviation and the minimum value of the proportional valve opening, the changes in the hydrogen inlet system pressure value, the changes in the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system are detected in real time, and diagnostic analysis is performed to obtain corresponding fault diagnosis results; When the corresponding fault diagnosis result simultaneously satisfies the corresponding preset diagnosis requirement and is maintained for a preset time length, a fuel cell system fault is determined.

2. A fuel cell system fault diagnosis method according to claim 1, characterized in that: The step of obtaining the fuel cell system operation data at different ambient temperatures based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located includes: Based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located, the temperature range is divided into a number of equidistant temperature intervals; At each temperature interval, all current density points are pulled to the rated operating conditions by the fuel cell system to obtain the operating data of the fuel cell system under different ambient temperatures.

3. A fuel cell system fault diagnosis method as claimed in claim 2, characterized in that: Based on the fuel cell system operation data at the different ambient temperatures, the minimum value of the hydrogen inlet pressure, the maximum value of the hydrogen inlet pressure deviation and the minimum value of the proportional valve opening are calibrated, including: Constructing a fuel cell system operation data table based on the fuel cell system operation data at the different ambient temperatures; Based on the fuel cell system operation data table, by linear table lookup, obtain the pressure reduction value of hydrogen entering the system when the steam trap is opened, the pressure increase value of hydrogen entering the fuel cell stack when the steam trap is opened, and the reduction value of the proportional valve opening when the steam trap is opened; Based on the hydrogen inlet system pressure reduction value when the steam trap is opened, the minimum value of the hydrogen inlet system pressure drop relative to the steady-state pressure is calibrated as the minimum hydrogen inlet system pressure value; Based on the increase value of the hydrogen inlet stack pressure when the steam trap is opened, calibrating the maximum value of the hydrogen inlet stack pressure deviation relative to the target pressure as the maximum value of the hydrogen inlet stack pressure deviation; Based on the decrease value of the proportional valve opening when the steam trap is opened, the minimum value of the proportional valve opening change relative to the target opening is calibrated as the minimum proportional valve opening value.

4. A fuel cell system fault diagnosis method according to claim 1, characterized in that: Based on the minimum value of the hydrogen inlet system pressure, the maximum value of the hydrogen inlet stack pressure deviation and the minimum value of the proportional valve opening, the changes in the hydrogen inlet system pressure value, the changes in the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system are detected in real time, and diagnostic analysis is performed to obtain corresponding fault diagnosis results, including: Based on the system opening instruction and the steam trap opening instruction, detecting whether the change in the pressure value of hydrogen entering the system is less than the minimum value of the hydrogen entering the system pressure, and obtaining a first fault diagnosis result; Based on the system start-up instruction, detecting whether the change in the pressure value of hydrogen entering the fuel cell stack is greater than the maximum value of the pressure deviation of hydrogen entering the fuel cell stack, and obtaining a second fault diagnosis result; Based on the system opening instruction, it is detected whether the opening size of the proportional valve is less than the minimum opening size of the proportional valve to obtain a third fault diagnosis result.

5. A fuel cell system fault diagnosis method as claimed in claim 4, characterized in that: When the corresponding fault diagnosis result simultaneously meets the corresponding preset diagnosis requirement and maintains the preset time length, determining that the fuel cell system is faulty includes: When the first fault diagnosis result is that the change in the hydrogen inlet system pressure value is detected to be less than the minimum value of the hydrogen inlet system pressure, a first fault warning result is obtained; When the second fault diagnosis result is that the change in the hydrogen inlet pressure value is greater than the maximum value of the hydrogen inlet pressure deviation, a second fault warning result is obtained; When the third fault diagnosis result is that the opening of the proportional valve is smaller than the minimum opening of the proportional valve, a third fault warning result is obtained; When the first fault warning result, the second fault warning result and the third fault warning result exist simultaneously and are maintained for a preset time length, it is determined that the fuel cell system is faulty.

6. A fuel cell system fault diagnosis method as claimed in claim 3, characterized in that: Also includes: Based on the fuel cell system operation data at the different ambient temperatures, calibrate the minimum change value of the hydrogen inlet pressure; Based on the minimum value of the hydrogen inlet system pressure, the minimum value of the hydrogen inlet stack pressure change and the minimum value of the proportional valve opening, the changes in the hydrogen inlet system pressure value, the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system are detected in real time, and diagnostic analysis is performed to obtain corresponding fault diagnosis results.

7. A fuel cell system fault diagnosis method as claimed in claim 6, characterized in that: Based on the fuel cell system operation data at different ambient temperatures, the minimum change value of the hydrogen inlet pressure is calibrated, including: Based on the fuel cell system operation data table, a change value of the hydrogen inlet stack pressure when the steam trap is opened is obtained by linear table lookup; Based on the change value of the hydrogen inlet stack pressure when the steam trap is opened, the minimum value of the hydrogen inlet stack pressure drop relative to the steady-state pressure is calibrated as the minimum value of the hydrogen inlet stack pressure change.

8. A fuel cell system fault diagnosis method as claimed in claim 7, characterized in that: Based on the minimum value of the hydrogen inlet pressure, the minimum value of the hydrogen inlet pressure change and the minimum value of the proportional valve opening, the changes in the hydrogen inlet pressure value, the hydrogen inlet pressure value and the proportional valve opening of the fuel cell system are detected in real time, and diagnostic analysis is performed to obtain corresponding fault diagnosis results, including: Based on the system opening instruction and the steam trap opening instruction, detecting whether the change in the pressure value of hydrogen entering the system is less than the minimum value of the hydrogen entering the system pressure, and obtaining a fourth fault diagnosis result; Based on the system opening instruction and the steam trap opening instruction, detecting whether the change in the pressure value of hydrogen entering the fuel cell stack is greater than the minimum value of the pressure change of hydrogen entering the fuel cell stack, and obtaining a fifth fault diagnosis result; Based on the system opening instruction and the steam trap opening instruction, it is detected whether the opening degree of the proportional valve is less than the minimum opening degree of the proportional valve, and a sixth fault diagnosis result is obtained.

9. A fuel cell system fault diagnosis system, characterized in that: Executing a fuel cell system fault diagnosis method according to any one of claims 1 to 8, comprising: Operation data acquisition module, threshold calibration module, diagnosis and analysis module and fault detection module; The operation data acquisition module is used to acquire the operation data of the fuel cell system under different ambient temperatures based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located; The threshold calibration module is used to calibrate the minimum value of hydrogen inlet pressure, the maximum value of hydrogen inlet pressure deviation and the minimum value of proportional valve opening based on the fuel cell system operation data under different ambient temperatures; The diagnostic analysis module is used to detect the changes in the hydrogen inlet system pressure value, the hydrogen inlet stack pressure value and the proportional valve opening of the fuel cell system in real time based on the minimum value of the hydrogen inlet system pressure, the maximum value of the hydrogen inlet stack pressure deviation and the minimum value of the proportional valve opening, and perform diagnostic analysis to obtain corresponding fault diagnosis results; The fault detection module is used to determine that the fuel cell system is faulty when the corresponding fault diagnosis result simultaneously meets the corresponding preset diagnosis requirement and is maintained for a preset time length.

10. A fuel cell system fault diagnosis system as claimed in claim 9, characterized in that: The operation data acquisition module is used to acquire the operation data of the fuel cell system under different ambient temperatures based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located, including: Temperature range division unit and system operation test unit; The temperature interval division unit is used to divide the temperature interval into a number of equidistant temperature intervals based on the upper and lower limits of the ambient temperature of the environment in which the fuel cell system is located; The system operation test unit is used to load all current density points to the rated operating conditions through the fuel cell system at each temperature interval point, so as to obtain the fuel cell system operation data under different ambient temperatures.

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