CN117673408A - Fuel cell cathode relative humidity control method and fuel cell controller - Google Patents
Fuel cell cathode relative humidity control method and fuel cell controller Download PDFInfo
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Abstract
The invention relates to a fuel cell cathode relative humidity control method and a fuel cell controller, wherein the method comprises the following steps: actual outlet relative humidity based on link gamma coordinate transformationPeriod after transformation of gamma coordinates of sum linkRelative humidity of the outletCalculating the expected inlet relative humidity through an outer ring anti-saturation inner mold quantitative process control structureAccording to the expected inlet relative humidity after the link ψ coordinate transformationActual inlet relative humidity after link ψ coordinate transformationCalculating a flow distribution coefficient χ through an inner ring anti-saturation inner mold quantitative process control structure hum The method comprises the steps of carrying out a first treatment on the surface of the The flow distribution coefficient χ hum Inputting the opening degree of the dehumidification valve into a nonlinear link phi, and calculating to obtain the opening degree of the dehumidification valve; wherein, the link Γ and the link ψ are embedded with environmental pressure, environmental temperature and relative humidity parameters. Compared with the prior art, the invention has strong environment adaptability, and can reduce the influence of the hysteresis and nonlinearity of the system on the dynamic tracking performance of the control system, thereby improving the efficiency and durability of the fuel cell.
Description
Technical Field
The present invention relates to the field of fuel cell system control technology, and in particular, to a method for controlling relative humidity of a cathode of a fuel cell and a fuel cell controller.
Background
The fuel cell is a clean energy conversion device with prospect, which takes hydrogen as a reducing agent and takes oxygen in the air as the reducing agent, and electrochemical reaction is carried out between an anode and a cathode to generate water and release electric energy and heat energy. At present, performance parameters such as fuel cell efficiency, service life and the like which limit the large-scale commercial popularization of the fuel cell are closely related to the relative humidity of the cathode. The relative humidity of the cathode is too high, liquid water can be accumulated in the cathode gas diffusion layer to cause gas diffusion channel blockage, serious concentration polarization is caused, the catalytic layer is damaged, and the efficiency and the service life of the fuel cell are reduced; ohmic polarization is aggravated when the relative humidity of the cathode is too low, and mechanical damage of the proton exchange membrane occurs when the proton exchange membrane is too dry, which is also unfavorable for performance of the fuel cell. Therefore, controlling the relative humidity of the cathode within a reasonable interval is an important part of the large-scale commercial popularization of the fuel cell.
For fuel cell cathode relative humidity control, there are the following methods:
1) In the Chinese patent application CN 116598537A, the humidity of the air in the stack is quickly adjusted by controlling different flow rates of dry gas/wet gas and controlling the dew point temperature of the wet gas and mixing the dry gas and the wet gas in different proportions, so that the air humidity can be quickly read and accurately adjusted, and the engineering requirements are met. However, the scheme only controls the air stack inlet humidity, does not control the cathode outlet humidity, and cannot know the humidity state in the cathode of the fuel cell; meanwhile, the scheme needs to be corrected according to actual conditions after a calculation result is obtained, the degree of automation is relatively low, and the environmental adaptability is relatively poor.
2) Paper literature (DOI 10.1016/j.ijhydene.2018.04.187) enables feedback PID control of cathode inlet relative humidity by mixing dry air and humid air and controlling the humid air flow. The scheme can not control the relative humidity of the cathode outlet, and can not quantitatively analyze the relative humidity state inside the cathode; secondly, the scheme does not consider the influence of the ambient pressure, the temperature and the relative humidity on the control of the relative humidity of the cathode, and the environmental adaptability of the algorithm is poor; finally, the solution does not consider that the dynamic process of the relative humidity is a slowly varying nonlinear process, and a specific solution is not provided for the hysteresis and nonlinearity of the dynamic process, so that a certain fluctuation phenomenon exists in the dynamic tracking process of the relative humidity in the solution.
The two schemes do not consider the influence of different environmental pressures, temperatures and relative humidity on the automatic control of the relative humidity of the cathode of the fuel cell, and the problems caused by the capacitive hysteresis and nonlinearity in the dynamic process of the relative humidity of the cathode are not solved, so that the environmental adaptability and the dynamic tracking performance are relatively poor.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a fuel cell cathode relative humidity control method and a fuel cell controller, which enhance the environment adaptability of a control system, reduce the influence of system hysteresis and nonlinearity on the dynamic tracking performance of the control system, thereby improving the efficiency and durability of the fuel cell
The aim of the invention can be achieved by the following technical scheme:
according to a first aspect of the present invention, there is provided a method of controlling the relative humidity of a cathode of a fuel cell by controlling the opening of a pressure reducing valve in an air supply system of the fuel cell, the method comprising:
actual outlet relative humidity based on link gamma coordinate transformationAnd the expected outlet relative humidity after the conversion of the link Γ coordinate +.>Calculating the expected inlet relative humidity through an outer ring anti-saturation inner mold quantitative process control structure
According to the expected inlet relative humidity after the link ψ coordinate transformationAnd the actual inlet relative humidity after the link ψ coordinate transformation +.>Calculating a flow distribution coefficient χ through an inner ring anti-saturation inner mold quantitative process control structure hum ；
The flow distribution coefficient χ hum Input to a nonlinear link phi, and calculate to obtain the opening alpha of the dehumidifying valve dhum ；
Wherein, the link Γ and the link ψ are embedded with environmental pressure, environmental temperature and relative humidity parameters.
Preferably, the fuel cell air supply system includes an ambient temperature sensor, an ambient relative humidity sensor, an ambient pressure sensor, an air cleaner, an air flow meter before an air compressor, an intercooler, a dehumidification valve, an air-air humidifier, a cathode inlet pressure sensor, a cathode inlet temperature sensor, a cathode inlet relative humidity sensor, a fuel cell stack, a cathode outlet pressure sensor, a cathode outlet temperature sensor, a cathode outlet relative humidity sensor, a back pressure valve, and a fuel cell controller;
the air filter, the front air flow meter of the air compressor, the intercooler, the dehumidifying valve and the air-air humidifier are sequentially connected through pipelines, a cathode inlet pressure sensor, a cathode inlet temperature sensor and a cathode inlet relative humidity sensor are arranged on a cathode inlet connecting pipeline of the air-air humidifier and the fuel cell stack, and a cathode outlet pressure sensor, a cathode outlet temperature sensor and a cathode outlet relative humidity sensor are arranged on a cathode outlet connecting pipeline of the air-air humidifier and the fuel cell stack; and the third outlet of the dehumidifying valve is directly connected to the outlet of the gas-gas humidifier in the pipeline for connecting the gas-gas humidifier with the cathode outlet of the fuel cell stack.
Preferably, the mathematical expression corresponding to the link Γ is:
wherein:the air flow before the air compressor is measured by an air flow meter (5) before the air compressor; m is M air Is the molar mass of the atmosphere; n is n cell The number of single cells in the fuel cell stack; beta is the water distribution coefficient; i st A fuel cell stack current; f is Faraday constant; />The cathode inlet pressure of the fuel cell stack is measured by a cathode inlet pressure sensor; />The cathode outlet pressure of the fuel cell stack is measured by a cathode outlet pressure sensor; t (T) cai The cathode inlet air temperature of the fuel cell stack is measured by a cathode inlet temperature sensor; t (T) cae The temperature of the air at the cathode outlet of the fuel cell stack is measured by a cathode outlet temperature sensor; p is p sat And (T) is the saturated vapor pressure of water at a temperature T.
Preferably, the outer loop anti-saturation inner model quantitative process control structure comprises an outer loop filtering link G f1 (s) outer loop anti-saturation inner mold quantitative process controller Gc 1 (S) outer ring saturation Ring S 1 And outer ring embedded model Gm 1 (s)；
Desired outlet relative humidity after transformation of link Γ coordinatesThrough the outer ring filtering link G f1 (s) subtracting the desired inlet relative humidity at the current time from the filtered output>Quantifying a process controller G via the internal mold controller c1 (s) subtracting the actual outlet relative humidity after transformation by the link Γ coordinate from the output of(s)>Relative humidity of inlet is expected from the current moment +.>Deviation of (2); the obtained signal is input into an outer ring saturation link S 1 Obtaining the desired inlet relative humidity at the next moment +.>
Preferably, the mathematical expression corresponding to the link ψ is:
wherein: t (T) amb Is the ambient temperature, and is measured by an ambient temperature sensor;is the ambient relative humidity, and is measured by an ambient relative humidity sensor; p is p amb Is the ambient pressure, and is measured by an ambient pressure sensor; t (T) amb Is the ambient temperature, and is measured by an ambient temperature sensor.
Preferably, the inner loop anti-saturation inner loop quantitative process control structure comprises an inner loop filtering link G f2 (s) inner loop anti-saturation inner die quantitative process controller Gc 2 (S) inner ring saturation ring S 2 And an inner ring embedded model Gm 2 (s)；
According to the expected inlet relative humidity after the link ψ coordinate transformationThrough inner loop filtering link G f2 (s) subtracting the actual inlet relative humidity after the link ψ coordinate transformation from the filtered output>Flow distribution coefficient χ with current moment hum Built-in model Gm through inner ring 2 (s) subtracting the current flow distribution coefficient χ from the deviation of the output hum Inner mold quantitative process controller Gc with inner ring anti-saturation 2 An output of(s); the obtained signal goes through an inner ring saturation link S 2 After processing, the flow distribution coefficient χ of the next moment is obtained hum 。
Preferably, the inner ring saturation ring S 2 The mathematical expression of (2) is:
wherein: η (eta) hum The water transmission efficiency of the gas-gas humidifier is;is cathode outlet relative humidity, measured by a cathode inlet relative humidity sensor (12); />For the cathode outlet mass flow, it can be calculated from the following equation:
wherein:the air flow before the air compressor is measured by an air flow meter (5) before the air compressor; n is n cell The number of single cells in the fuel cell stack (13); beta is the water distribution coefficient; i st A fuel cell stack current; f is Faraday constant; />Is the molar mass of water; />Is the oxygen molar mass.
Preferably, the mathematical expression corresponding to the nonlinear link Φ is specifically:
wherein: t (T) amb Is the ambient temperature, and is measured by an ambient temperature sensor;the cathode inlet pressure of the fuel cell stack is measured by a cathode inlet pressure sensor; t (T) cai The cathode inlet air temperature of the fuel cell stack is measured by a cathode inlet temperature sensor; />Is the ambient relative humidity, and is measured by an ambient relative humidity sensor; p is p amb Is the ambient pressure, measured by an ambient pressure sensor.
Preferably, the experiment for obtaining the nonlinear transformation Φ specifically includes: the fuel cell stack is replaced by a cavity with the same volume as the fuel cell, two air flow meters are arranged on a loop without a humidifier and a loop with the humidifier, and then the rotating speed N of the air compressor is fixed AC And back pressure valve opening alpha bpv Changing the opening alpha of the dehumidifying valve dhum And recording the ratio of the flow rates of the two loops under different opening degrees, and obtaining a nonlinear transformation phi expression by a curve fitting mode.
According to a second aspect of the present invention there is provided a fuel cell controller storing a computer program which when executed implements a method as any one of the above.
Compared with the prior art, the invention has the following beneficial effects:
1) The invention adopts a cascade anti-saturation internal model quantitative process control structure, and through the inner ring anti-saturation internal model quantitative process control and the outer ring anti-saturation internal model quantitative process control, the disturbance of the internal process (mass transfer, heat transfer, electrochemical process and the like) of the electric pile and the air flow process of the air supply system on the control of the relative humidity of the cathode is respectively weakened, so that the stability of the system is enhanced.
2) According to the invention, the influence of the ambient pressure, the temperature and the relative humidity on the relative humidity of the cathode is considered, and the environmental factors are embedded into the anti-saturation internal model quantitative process control structure in a mode of converting the coordinates of the gamma link and the phi link, so that the environmental adaptability of the system is improved.
3) The invention adopts a cascade control structure and a coordinate transformation mode, reduces the influence of capacitive hysteresis and nonlinearity on the system performance, and enhances the dynamic tracking capability of the system.
Drawings
FIG. 1 is a schematic diagram of a fuel cell air supply system of the present invention;
FIG. 2 is a schematic diagram of an experimental platform structure of a nonlinear transformation phi acquisition experiment of the invention;
FIG. 3 is a schematic diagram of a cathode relative humidity control structure of a fuel cell according to the present invention;
reference numerals: 1. an ambient temperature sensor; 2. an ambient relative humidity sensor; 3. an ambient pressure sensor; 4. an air cleaner; 5. front air flow meter of air compressor; 6. an air compressor; 7. an intercooler; 8. a dehumidifying valve; 9. an air-air humidifier; 10. a cathode inlet pressure sensor; 11. a cathode inlet temperature sensor; 12. a cathode inlet relative humidity sensor; 13. a fuel cell stack; 14. a cathode outlet pressure sensor; 15. a cathode outlet temperature sensor; 16. a cathode outlet relative humidity sensor; 17. a back pressure valve; 18. a fuel cell controller; 19. a chamber having an equal volume to the cathode; 20. a humidifier-free loop air flow meter; 21. there is a humidifier circuit air flow meter.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
Examples
As shown in fig. 1 to 3, the embodiment provides a method for controlling the relative humidity of a cathode of a fuel cell, which specifically includes the following real-time processes:
building a fuel cell air supply system: air enters the air supply system through the air filter 4, the mass flow of the air is measured through the air flowmeter 5 before the air compressor, the data are transmitted to the fuel cell controller 18 and then enter the air compressor 6, the temperature is reduced through the intercooler 7, the air enters the fuel cell stack 13 through two branches with the air-air humidifier 9 and without the humidifier respectively through the dehumidifying valve 8, the pressure, the temperature and the relative humidity of the air need to be measured before through the cathode inlet pressure sensor 10, the cathode inlet temperature sensor 11 and the cathode inlet relative humidity sensor 12, the related data are transmitted to the fuel cell controller 18, the air is returned to the air-air humidifier 9 and humidified after the fuel cell stack 13 participates in electrochemical reaction, and finally the air is discharged out of the air supply system through the back pressure valve 17 to the atmosphere.
Building a nonlinear transformation phi acquisition experimental platform: the fuel cell stack 13 is replaced by a cavity 19 having the same volume as the fuel cell to avoid damaging the stack, and two air flow meters 20, 21 are installed on the two loops without and with the humidifier, after which the rotation speed N of the air compressor 6 is fixed AC And the opening alpha of the back pressure valve 17 bpv Changing the opening alpha of the dehumidifying valve 8 dhum And recording the ratio of the flow rates of the two loops under different opening degrees, and obtaining a nonlinear transformation phi expression by a curve fitting mode.
After the nonlinear transformation Φ expression is obtained, the air supply system is restored to the state at the time of construction, the air flow meters 20, 21 are removed, and the fuel cell stack 13 is put back in place.
Through linkΓ versus actual outlet relative humidity(in%) and the desired outlet relative humidity +.>(unit:%) and performing transformation, wherein the link Γ is the following function:
wherein the method comprises the steps ofThe air flow before the air compressor is measured by an air flow meter before the air compressor, and the unit is as follows: g s -1 ；M air The molar mass of the atmosphere was taken as 29g mol -1 ；n cell The number of single cells in the fuel cell stack; beta is the water distribution coefficient, and is taken as 1; i st The fuel cell stack current is in units of: a, A is as follows; f is Faraday constant, taken as 96485C mol -1 ；/>The cathode inlet pressure of the fuel cell stack is measured by a cathode inlet pressure sensor, and the unit is as follows: pa; />The cathode outlet pressure of the fuel cell stack is measured by a cathode outlet pressure sensor, and the unit is as follows: pa; t (T) cai The cathode inlet air temperature of the fuel cell stack is measured by a cathode inlet temperature sensor, and the unit is: k, performing K; t (T) cae The cathode outlet air temperature of the fuel cell stack is measured by a cathode outlet temperature sensor, and the unit is: K. p is p sat The saturated vapor pressure (unit: pa) of water at a temperature T can be calculated by the following formula:
p sat (T)＝1000f(T)
calculating the expected inlet relative humidity through an outer ring anti-saturation inner mold quantitative process control structureThe outer ring anti-saturation inner mold quantitative process control structure comprises an outer ring filtering link G f1 (s) outer loop anti-saturation inner mold quantitative process controller Gc 1 (S) outer ring saturation Ring S 1 And outer ring embedded model Gm 1 (s) the mathematical expressions are:
wherein: t (T) f1 ，T m1 And T c1 The control parameters are obtained through calibration.
Desired outlet relative humidity after transformation of link Γ coordinatesThrough the outer ring filtering link G f1 (s) subtracting the desired inlet relative humidity at the current time from the filtered output>Quantifying a process controller G via the internal mold controller c1 (s) subtracting the actual outlet relative humidity after transformation by the link Γ coordinate from the output of(s)>Relative humidity of inlet is expected from the current moment +.>Deviation of (2); the obtained signal is input into an outer ring saturation link S 1 Obtaining the desired inlet relative humidity at the next moment +.>
By link ψ to actual inlet relative humidity(in%) and the desired inlet relative humidity +.>(unit:%) and performing transformation, wherein the link ψ is the following function:
wherein: t (T) amb The unit is measured by an ambient temperature sensor, which is the ambient temperature: k, performing K;the unit is measured by an ambient relative humidity sensor for ambient relative humidity: the%; p is p amb Is the ambient pressure, measured by an ambient pressure sensor, in units of: pa.
Calculating a flow distribution coefficient χ through an inner ring anti-saturation inner mold quantitative process control structure hum Wherein the inner loop anti-saturation inner die quantitative process control structure comprises an inner loop filtering link G f2 (s) inner loop anti-saturation inner mold quantification procedureController Gc 2 (S) inner ring saturation ring S 2 And an inner ring embedded model Gm 2 (s) respectively:
wherein: t (T) f2 ，T m2 And T c2 The control parameters are obtained through calibration. η (eta) hum The water transmission efficiency of the air-air humidifier is characteristic parameters, and can be checked by a factory specification of the air-air humidifier;is the cathode outlet relative humidity, measured by a cathode inlet relative humidity sensor (12), in units of: the%; />The cathode outlet mass flow can be calculated in units of: g s -1 ：
Wherein,is water molar mass, taken as 18g mol -1 ；/>The molar mass of oxygen is taken to be 32gmol -1 。
According to the expected inlet relative humidity after the link ψ coordinate transformationThrough inner loop filtering link G f2 (s) subtracting the actual inlet relative humidity after the link ψ coordinate transformation from the filtered output>Flow distribution coefficient χ with current moment hum Built-in model Gm through inner ring 2 (s) subtracting the current flow distribution coefficient χ from the deviation of the output hum Inner mold quantitative process controller Gc with inner ring anti-saturation 2 An output of(s); the obtained signal goes through an inner ring saturation link S 2 After processing, the flow distribution coefficient χ of the next moment is obtained hum 。
The flow distribution coefficient χ hum Obtaining the opening alpha of the dehumidifying valve through nonlinear link phi transformation processing dhum 。
The present embodiment also provides a fuel cell controller storing a computer program which when executed implements any of the methods described above.
In summary, the method for controlling the relative humidity of the cathode of the fuel cell, which is designed by the invention, is used for the quantitative process control of the cathode outlet relative humidity self-adaptive cascade anti-saturation internal model of the fuel cell under different environmental pressures, environmental temperatures and environmental humidities, so as to improve the efficiency and the service life of the fuel cell.
The invention is composed of an outer ring anti-saturation inner mold quantitative process control structure, an inner ring anti-saturation inner mold quantitative process control structure, a gamma link, a phi link, a psi link and the like. The outer ring anti-saturation inner model quantitative process control structure comprises an outer ring filtering link, an outer ring anti-saturation inner model quantitative process controller, an outer ring saturation link and an outer ring embedded model, so that the control of the relative humidity of a cathode outlet is realized, and the expected relative humidity of a cathode inlet is obtained; the inner ring anti-saturation inner mold quantitative process control structure comprises an inner ring filtering link, an inner ring anti-saturation inner mold quantitative process controller, an inner ring saturation link and an inner ring embedded model so as to control the relative humidity of a cathode inlet; the gamma link and the phi link respectively carry out coordinate transformation on the relative humidity of the cathode outlet of the fuel cell and the flow distribution coefficient so as to reduce the influence of the nonlinearity of the system on the control of the relative humidity; and the psi link performs coordinate transformation on the relative humidity of the cathode inlet by introducing the ambient pressure, the ambient temperature and the ambient humidity so as to improve the environment adaptability of the system.
The invention considers the environmental influence factors, reduces the influence of capacitive hysteresis and nonlinearity on the system performance, weakens the disturbance of the internal process (mass transfer, heat transfer, electrochemical process and the like) of the galvanic pile and the air flow process of the air supply system on the control of the relative humidity of the cathode, and has the advantages of strong environmental adaptability, high stability, good dynamic tracking performance and the like.
While the invention has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.
Claims (10)
1. A method for controlling the relative humidity of a cathode of a fuel cell by controlling the opening of a pressure reducing valve in an air supply system of the fuel cell, the method comprising:
actual outlet relative humidity based on link gamma coordinate transformationAnd the expected outlet relative humidity after the conversion of the link Γ coordinate +.>Quantitative oversaturation by an outer ring anti-saturation inner moldThe control structure calculates the desired inlet relative humidity +.>
According to the expected inlet relative humidity after the link ψ coordinate transformationAnd the actual inlet relative humidity after the link ψ coordinate transformation +.>Calculating a flow distribution coefficient χ through an inner ring anti-saturation inner mold quantitative process control structure hum ；
The flow distribution coefficient χ hum Input to a nonlinear link phi, and calculate to obtain the opening alpha of the dehumidifying valve dhum ；
Wherein, the link Γ and the link ψ are embedded with environmental pressure, environmental temperature and relative humidity parameters.
2. The method according to claim 1, wherein the fuel cell air supply system comprises an ambient temperature sensor (1), an ambient relative humidity sensor (2), an ambient pressure sensor (3), an air cleaner (4), an air pre-air flow meter (5), an air compressor (6), an intercooler (7), a dehumidification valve (8), an air-air humidifier (9), a cathode inlet pressure sensor (10), a cathode inlet temperature sensor (11), a cathode inlet relative humidity sensor (12), a fuel cell stack (13), a cathode outlet pressure sensor (14), a cathode outlet temperature sensor (15), a cathode outlet relative humidity sensor (16), a back pressure valve (17), and a fuel cell controller (18);
the air filter (4), an air flow meter (5) in front of the air compressor, the air compressor (6), an intercooler (7), a dehumidifying valve (8) and an air-air humidifier (9) are sequentially connected through pipelines, a cathode inlet pressure sensor (10), a cathode inlet temperature sensor (11) and a cathode inlet relative humidity sensor (12) are arranged on a cathode inlet connecting pipeline of the air-air humidifier (9) and a fuel cell stack (13), and a cathode outlet pressure sensor (14), a cathode outlet temperature sensor (15) and a cathode outlet relative humidity sensor (16) are arranged on a cathode outlet connecting pipeline of the air-air humidifier (9) and the fuel cell stack (13); the third outlet of the dehumidifying valve (8) is directly connected to the outlet of the gas-gas humidifier (9) in a pipeline connecting the gas-gas humidifier (9) with the cathode outlet of the fuel cell stack (13).
3. The method for controlling the relative humidity of the cathode of a fuel cell according to claim 2, wherein the mathematical expression corresponding to the link Γ is:
wherein:the air flow before the air compressor is measured by an air flow meter (5) before the air compressor; m is M air Is the molar mass of the atmosphere; n is n cell The number of single cells in the fuel cell stack (13); beta is the water distribution coefficient; i st A fuel cell stack current; f is Faraday constant; />Is the cathode inlet pressure of the fuel cell stack, and is measured by a cathode inlet pressure sensor (10); />The cathode outlet pressure of the fuel cell stack is measured by a cathode outlet pressure sensor (14); t (T) cai The cathode inlet air temperature of the fuel cell stack is measured by a cathode inlet temperature sensor (11); t (T) cae The temperature of the cathode outlet air of the fuel cell stack is measured by a cathode outlet temperature sensor (15); p is p sat (T) is a temperature ofSaturated vapor pressure of water at T.
4. The method of claim 2, wherein the outer loop anti-saturation inner model quantitative process control structure comprises an outer loop filter element G f1 (s) outer loop anti-saturation inner mold quantitative process controller Gc 1 (S) outer ring saturation Ring S 1 And outer ring embedded model Gm 1 (s)；
Desired outlet relative humidity after transformation of link Γ coordinatesThrough the outer ring filtering link G f1 (s) subtracting the desired inlet relative humidity at the current time from the filtered output>Quantifying a process controller G via the internal mold controller c1 (s) subtracting the actual outlet relative humidity after transformation by the link Γ coordinate from the output of(s)>Relative humidity of inlet is expected from the current moment +.>Deviation of (2); the obtained signal is input into an outer ring saturation link S 1 Obtaining the desired inlet relative humidity at the next moment
5. The method for controlling the relative humidity of the cathode of the fuel cell according to claim 2, wherein the mathematical expression corresponding to the link ψ is:
wherein: t (T) amb Is the ambient temperature, and is measured by an ambient temperature sensor (1);is the ambient relative humidity, and is measured by an ambient relative humidity sensor (2); p is p amb Is the ambient pressure, and is measured by an ambient pressure sensor (3); t (T) amb Is an ambient temperature, and is measured by an ambient temperature sensor (1).
6. The method of claim 2, wherein the inner loop anti-saturation inner mode quantitative process control structure comprises an inner loop filter element G f2 (s) inner loop anti-saturation inner die quantitative process controller Gc 2 (S) inner ring saturation ring S 2 And an inner ring embedded model Gm 2 (s)；
According to the expected inlet relative humidity after the link ψ coordinate transformationThrough inner loop filtering link G f2 (s) subtracting the actual inlet relative humidity after the link ψ coordinate transformation from the filtered output>Flow distribution coefficient χ with current moment hum Built-in model Gm through inner ring 2 (s) subtracting the current flow distribution coefficient χ from the deviation of the output hum Inner mold quantitative process controller Gc with inner ring anti-saturation 2 An output of(s); the obtained signal goes through an inner ring saturation link S 2 After processing, the flow distribution coefficient χ of the next moment is obtained hum 。
7. The method for controlling the relative humidity of a cathode of a fuel cell according to claim 6, wherein the inner ring saturation step S 2 Mathematical expression of (a)The formula is:
wherein: η (eta) hum The water transmission efficiency of the gas-gas humidifier is;is cathode outlet relative humidity, measured by a cathode inlet relative humidity sensor (12); />For the cathode outlet mass flow, it can be calculated from the following equation:
wherein:the air flow before the air compressor is measured by an air flow meter (5) before the air compressor; n is n cell The number of single cells in the fuel cell stack (13); beta is the water distribution coefficient; i st A fuel cell stack current; f is Faraday constant;is the molar mass of water; />Is the oxygen molar mass.
8. The method for controlling the relative humidity of the cathode of the fuel cell according to claim 2, wherein the mathematical expression corresponding to the nonlinear element Φ is specifically:
wherein: t (T) amb Is the ambient temperature, and is measured by an ambient temperature sensor (1);is the cathode inlet pressure of the fuel cell stack, and is measured by a cathode inlet pressure sensor (10); t (T) cai The cathode inlet air temperature of the fuel cell stack is measured by a cathode inlet temperature sensor (11); />Is the ambient relative humidity, and is measured by an ambient relative humidity sensor (2); p is p amb Is the ambient pressure, and is measured by an ambient pressure sensor (3).
9. The method for controlling the relative humidity of the cathode of the fuel cell according to claim 8, wherein the experiment for obtaining the nonlinear transformation Φ specifically comprises: the fuel cell stack (13) is replaced by a cavity with the same volume as the fuel cell, two air flow meters are arranged on a loop without a humidifier and a loop with the humidifier, and then the rotating speed N of the air compressor (6) is fixed AC And the opening alpha of the back pressure valve (17) bpv Changing the opening alpha of the dehumidifying valve (8) dhum And recording the ratio of the flow rates of the two loops under different opening degrees, and obtaining a nonlinear transformation phi expression by a curve fitting mode.
10. A fuel cell controller storing a computer program, characterized in that the method according to any one of claims 1 to 9 is implemented when the program is executed.
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