A fuel cell hydrogen supply subsystem modeling and simulation control method

Abstract

The present invention provides a fuel cell hydrogen supply subsystem modeling and simulation control method, which relates to the field of fuel cell technology, including: selecting a fuel cell stack model, a hydrogen circulation pump model, a gas-liquid separator model, a drain valve model, a switch valve model, a proportional valve model, a nitrogen exhaust valve model and a hydrogen heater model in simulation software; connecting the hydrogen heater model to the anode inlet of the fuel cell stack model through the switch valve model and the proportional valve model in sequence; connecting one end of the gas-liquid separator model to the anode outlet of the fuel cell stack model; connecting the other end of the gas-liquid separator model to the drain valve model; connecting the hydrogen circulation pump between the outlet end of the gas-liquid separator and the anode inlet of the fuel cell stack model; and connecting the nitrogen exhaust valve to the anode outlet of the fuel cell stack model. The present invention takes the actual fuel cell hydrogen supply subsystem as a model, models some components of the hydrogen supply subsystem of the hydrogen fuel cell, and controls the pressure and temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a modeling and simulation control method for a hydrogen supply subsystem of a fuel cell. Background Art

[0002] A fuel cell is an energy conversion device that converts chemical energy into electrical energy. Proton exchange membrane fuel cells use hydrogen as fuel and oxygen as oxidant to produce energy and water through electrochemical reactions. Hydrogen fuel cells using hydrogen as fuel can isothermally convert chemical energy directly into electrical energy according to chemical formulas, thereby replacing traditional engines as a driving force for automobiles.

[0003] The hydrogen supply subsystem is one of the important subsystems of the fuel cell system, which provides reaction fuel for the fuel cell system. The reaction fuel can only fully react with the oxidant in the fuel cell stack under certain flow, pressure, temperature and humidity, so as to maximize the efficiency of the fuel cell system. In order to ensure that the control of various parameters is stable and accurate when the anode hydrogen enters the stack, a certain control strategy is required to dynamically coordinate and control various functional parts. Therefore, a fuel cell hydrogen supply subsystem model is built through software, and the reaction process and control process of the actual fuel cell hydrogen supply subsystem model are simulated. The system design scheme and matching parameters are evaluated and optimized in the early stage of the project, and the possible failures of the hydrogen supply subsystem are simulated, such as component failure, etc., to reduce the risks and costs in the actual fuel cell system test process, and provide effective guidance for the development of fuel cell systems.

[0004] In the prior art, patent CN116666697A discloses a pressure control system and method based on a digital twin fuel cell hydrogen supply system, which mentions that a physical entity test device for the hydrogen supply subsystem must be built first, the physical model test data must be collected, and then the simulation model parameters must be calibrated and corrected. This method has a long development cycle and high cost.

[0005] Patent CN113097542A discloses a fuel cell air system modeling and simulation method based on AMESim and patent CN116130711A discloses a fuel cell thermal management modeling and simulation method based on AMESim. It is proposed to use AMESim software to construct the basic models of the two subsystems of air and thermal management, but there is no research on the hydrogen inlet pressure and temperature control strategy.

[0006] In addition, in the prior art, such as CN114388853B, although the modeling method of the fuel cell hydrogen system integrated with the virtual stack model is realized, it focuses on the construction of the gas path model. Since it uses a virtual stack model, the virtual stack model is only a chamber that can enter and exit water and hydrogen, but cannot simulate the electrochemical reaction of the stack, and cannot realize the simulation of the reaction process of the real fuel cell hydrogen system, and thus cannot provide effective guidance for the actual fuel cell system test process. Summary of the invention

[0007] Aiming at the control problems such as how to model the hydrogen supply subsystem, unstable hydrogen inlet pressure, and low hydrogen inlet temperature, the present invention provides a fuel cell hydrogen supply subsystem modeling and simulation control method. Taking the actual fuel cell hydrogen supply subsystem as a model, some components of the hydrogen supply subsystem of the hydrogen fuel cell are modeled and the pressure and temperature are controlled in the AMEsim software.

[0008] To this end, the present invention adopts the following technical solutions:

[0009] In one aspect, the present invention provides a fuel cell hydrogen supply subsystem modeling method, the method comprising:

[0010] In the AMEsim software, a fuel cell stack model, a hydrogen circulation pump model, a gas-liquid separator model, a drain valve model, a switch valve model, a proportional valve model, a nitrogen exhaust valve model and a hydrogen heater model are selected; the fuel cell stack model is a built-in stack model of the AMEsim software; the stack model is a multi-physics field model, which uses an electrochemical parameter fitting tool to evaluate the electrochemical reaction material consumption, hydrogen consumption, stack heating value, mass flow, pressure, temperature and humidity parameter monitoring and control of the fuel cell system; the hydrogen circulation pump model is a hydrogen circulation pump model for gas mixture applications in the AMEsim software, which can meet the hydrogen inlet flow requirements under different working conditions by controlling the speed of the hydrogen circulation pump; the gas-liquid separator model It is an evaporation condensation chamber model for gas-water separation in AMEsim software; the drain valve model is a 2-port 2-position hydraulic valve model in AMEsim software, and its valve opening time and valve opening angle are controlled by signal input; the switch valve model is a two-way solenoid valve model for gas mixture application in AMEsim software; the proportional valve model is a two-way solenoid valve model for gas mixture application in AMEsim software; the nitrogen exhaust valve model is a two-way solenoid valve model for gas mixture application in AMEsim software; the nitrogen exhaust valve and the drain valve periodically switch in coordination with the proportional valve at the hydrogen inlet end of the fuel cell stack, thereby achieving the function of stabilizing the hydrogen inlet pressure; the hydrogen heater model is a two-and-a-half heat exchanger model in AMEsim software;

[0011] The hydrogen heater model is connected to the anode inlet of the fuel cell stack model through the switch valve model and the proportional valve model in sequence; one end of the gas-liquid separator model is connected to the anode outlet of the fuel cell stack model; the other end of the gas-liquid separator model is connected to the drain valve model; the hydrogen circulation pump is connected between the outlet end of the gas-liquid separator and the anode inlet of the fuel cell stack model; and the nitrogen exhaust valve is connected to the anode outlet of the fuel cell stack model.

[0012] Furthermore, it also includes: setting a pressure sensor, a temperature sensor and a humidity sensor at the anode inlet and the anode outlet of the fuel cell stack model respectively to monitor the pressure, temperature and humidity of the fuel cell stack respectively.

[0013] Furthermore, it also includes: a controller of a proportional valve is arranged between the proportional valve model and the pressure sensor arranged at the anode inlet; and the controller is a PID controller.

[0014] Furthermore, a fuel cell stack model is selected in the AMEsim software, including:

[0015] The battery stack model included in the AMEsim software is selected, and the air subsystem model and the thermal management subsystem model in the battery stack model are simplified;

[0016] Adjust the hydrogen chamber pressure drop parameters according to different operating conditions of the fuel cell stack.

[0017] Furthermore, a hydrogen ejector and a hydrogen spray are used to replace the hydrogen circulation pump.

[0018] Furthermore, the drain valve and the nitrogen exhaust valve are integrated on the gas-liquid separator and used simultaneously.

[0019] In another aspect, the present invention further provides a simulation control method for a fuel cell hydrogen supply subsystem, which is applied to a fuel cell hydrogen supply subsystem model constructed by the above fuel cell hydrogen supply subsystem modeling method;

[0020] The high-pressure gas source outputs hydrogen to the hydrogen heater model. The outlet pressure of the high-pressure gas source is input according to the actual gas source pressure, and the inlet temperature of the high-pressure gas source is the ambient temperature.

[0021] Hydrogen is heated by liquid cooling through the hydrogen heater model. The coolant temperature in the hydrogen heater model is set as a variable to simulate the change of the coolant temperature in the system over time. The temperature entering the stack is monitored through the hydrogen inlet temperature monitoring point, thereby controlling the coolant flow of the hydrogen heater, and then controlling the gas inlet temperature to meet the hydrogen inlet temperature requirements, thereby improving the electrochemical reaction efficiency in the fuel cell stack;

[0022] The heated hydrogen passes through the switch valve model and then the proportional valve model to reduce pressure, regulate and stabilize the pressure before entering the fuel cell stack model. The pressure sensor, temperature sensor and humidity sensor at the anode inlet of the fuel cell stack model monitor the pressure, temperature and humidity of the stack respectively.

[0023] The gas after the reaction is discharged through the anode outlet of the fuel cell stack model. Part of it is periodically discharged from the system through the nitrogen exhaust valve model, and the other part is separated from the water by the gas-liquid separator model. It is then pressurized by the hydrogen circulation pump model to make the recycled hydrogen mixed with the new hydrogen and then enter the fuel cell stack model to participate in the electrochemical reaction. The separated liquid water is periodically discharged from the system through the drain valve model.

[0024] Furthermore, the opening of the drain valve model is controlled by the liquid level height of the water storage box on the front-end gas-liquid separator, and the liquid level height of the water storage box is controlled by a liquid level sensor on the water storage box.

[0025] Furthermore, the opening of the drain valve model is controlled by the liquid level height of the water storage box in the front-end gas-liquid separator, including: setting the liquid level height of the water storage box to H1 when the drain valve is opened, and the liquid level height of the water storage box to H2 when the drain valve is closed; when the liquid level sensor in the water storage box monitors the liquid level to be H, if H>H1 at this time, the drain valve is opened; after the drain valve is opened, when the liquid level sensor monitors the liquid level to be H2, the drain valve is closed.

[0026] Furthermore, the control of the proportional valve model includes:

[0027] Given the preset pressure of hydrogen under different system working conditions, the preset pressure of hydrogen under different operating conditions is set as P1, the corresponding actual hydrogen inlet pressure is P2, and the air inlet pressure is P3;

[0028] The difference between the air inlet pressure P3 and the hydrogen preset pressure P1 is obtained , the difference between the air inlet pressure P3 and the hydrogen inlet pressure P2 is obtained ,contrast and Value size;

[0029] when > , then the numerical value M is output, which controls the proportional coefficient, integral time and differential time of the PID controller of the proportional valve, adjusts the duty cycle of PWM, thereby controlling the opening of the proportional valve, reducing the fluctuation value of the hydrogen inlet pressure at each operating point, and playing a role in stabilizing the inlet pressure;

[0030] like ≤ , then the output value N, the value N controls the proportional coefficient, integral time and differential time of the PID controller of the proportional valve, adjusts the duty cycle of PWM, thereby controlling the opening of the proportional valve, reducing the fluctuation value of the hydrogen inlet pressure at each operating point, and playing a role in stabilizing the inlet pressure.

[0031] The above technical solution has the following beneficial effects:

[0032] The present invention realizes the construction of a complete model of the fuel cell hydrogen supply subsystem, realizes the control of the hydrogen circulation pump speed, proportional valve opening, drain valve, nitrogen exhaust valve, and hydrogen heater, realizes the control of the inlet pressure, temperature and humidity value of the hydrogen supply subsystem, realizes the precise control of the inlet flow and pressure under different working conditions, and realizes that the fuel cell system can reach a stable state in a short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 It is a schematic diagram of the hydrogen supply subsystem of a fuel cell in the prior art;

[0035] Figure 2 A schematic diagram of a basic model of a fuel cell stack in an embodiment of the present invention;

[0036] Figure 3 A schematic diagram of a fuel cell stack optimization model in an embodiment of the present invention;

[0037] Figure 4 A simulation model diagram of a hydrogen supply subsystem in an embodiment of the present invention;

[0038] Figure 5 This is a control flow chart of the hydrogen gas feeding into the stack pressure stabilization strategy in an embodiment of the present invention;

[0039] Figure 6 This is a result diagram of the simulation value of hydrogen inlet pressure in an embodiment of the present invention;

[0040] Figure 7 A comparison diagram of the actual measured value and the simulated value of the hydrogen inlet pressure in the embodiment of the present invention;

[0041] Figure 8 This is a comparison diagram of the actual measured value and the simulated value of the hydrogen inlet temperature in the embodiment of the present invention;

[0042] In the figure, 1. fuel cell stack; 2. switch valve; 3. proportional valve; 4. gas-liquid separator; 5. nitrogen exhaust valve; 6. water drain valve; 7. hydrogen heater; 8. hydrogen circulation pump. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0044] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0045] The basic principle of the fuel cell hydrogen supply subsystem is as follows: Figure 1 As shown, high-pressure hydrogen flows out of the high-pressure hydrogen bottle, is heated by the hydrogen heater, and the switch valve of the hydrogen supply subsystem is opened. The proportional valve then adjusts the pressure and enters the stack through the anode inlet of the stack to participate in the electrochemical reaction. The reacted gas is discharged through the anode outlet of the stack, and the water vapor contained in the anode outlet exhaust gas is separated by the gas-liquid separator, and discharged out of the system through the tail discharge device through the drain valve. At the same time, the unreacted hydrogen is boosted by the hydrogen circulation pump and re-enters the stack to participate in the electrochemical reaction, thereby improving the utilization rate of hydrogen. The nitrogen exhaust valve is opened periodically, and the nitrogen in the anode of the stack is intermittently discharged out of the system. The corresponding parameter changes at the inlet and outlet of the stack are monitored by pressure, temperature and humidity sensors. There are two chambers in the hydrogen heater. The new hydrogen is heated by the coolant in the system, and the coolant flow in the cooling chamber of the hydrogen heater is adjusted to control the temperature of the hydrogen entering the anode.

[0046] In the embodiment of the present invention, based on the principle of the above-mentioned hydrogen supply subsystem, a fuel cell hydrogen supply subsystem simulation model based on AMEsim is built, and the key BOP (Balance of Plant, which refers to other components in the hydrogen fuel cell system except the fuel cell stack, including hydrogen storage tanks, oxygen storage tanks, hydrogen and oxygen supply systems, battery control systems, cooling systems, battery heating systems, battery exhaust systems, etc.) component models such as the battery stack, hydrogen heater, hydrogen circulation pump, switch valve, proportional valve, gas-liquid separator, drain valve and nitrogen exhaust valve are mainly established. Specifically:

[0047] S1. Build a fuel cell stack model;

[0048] The present invention adopts the built-in stack model of AMEsim software (AMEsim software is a one-dimensional simulation platform for modeling complex systems in multiple disciplines). This model is a multi-physics field model, which uses electrochemical parameter fitting tools to evaluate the electrochemical reaction material consumption, hydrogen consumption, stack heat generation, mass flow, pressure, temperature, humidity and other parameter monitoring and control of the fuel cell system. The stack model can input the actual number of membrane electrode sheets of the stack, the effective reaction area of ​​a single stack and the UI polarization curve of the stack. By inputting different current densities, the output voltage value of the fuel cell stack under different current densities can be calculated; the proportion of water generated at the anode outlet is calculated, such as the proportion of water generated at the anode by electrochemical reactions, the proportion of water formed during the migration of hydrogen ions from the anode to the cathode, and the proportion of cathode water diffused to the anode water due to concentration diffusion; the amount of water discharged from the anode directly affects the separation effect of the gas-liquid separator and the valve opening period of the nitrogen exhaust valve and the water drain valve, thereby affecting the control and regulation of the hydrogen inlet pressure. In this embodiment, only the hydrogen supply subsystem simulation model is considered, and the air subsystem model and the thermal management subsystem model are simplified. The stack model is as follows: Figure 2 This stack model takes into account parameters such as the number of actual fuel cell stacks, the electrochemical active area of ​​a single cell, and the thickness of the membrane electrode, but does not take into account the volume of the hydrogen chamber in the stack and the pressure drop of the hydrogen chamber in the stack. In this embodiment, the hydrogen chamber pressure drop parameter is adjusted according to different working conditions of the stack to make the entire fuel cell stack model more in line with actual needs. The specific optimization model is as follows: Figure 3 shown.

[0049] S2, construct a hydrogen circulation pump model;

[0050] The hydrogen circulation pump is the core component of the entire hydrogen supply subsystem. It can recycle hydrogen that does not participate in the electrochemical reaction to improve the utilization rate of hydrogen. Its main parameters such as pressure ratio, circulation flow, speed, efficiency, etc. are provided by the supplier. In this embodiment, the hydrogen circulation pump model for gas mixture application is selected in the AMEsim software. The speed-flow-pressure ratio MAP diagram of the actual hydrogen circulation pump needs to be input into the model, but the input mass flow and speed need to be corrected in this model, as follows:

[0051] The hydrogen circulation pump pressure ratio can be expressed as:

[0052] ;

[0053] in, is the corrected mass flow rate in kg / s, Correction speed (rpm).

[0054] Can be calculated by a specific expression and :

[0055] ;

[0056] ;

[0057] Right now:

[0058] ;

[0059] ;

[0060] in, is the correction speed (rev / min); is the actual speed (rev / min); is the corrected mass flow rate (kg / s); is the actual mass flow rate (kg / s); is the inlet temperature (K); is the outlet temperature (K); is the inlet absolute pressure (bar); is the standard pressure (bar).

[0061] A hydrogen circulation pump is used instead of an ejector. By controlling the speed of the hydrogen circulation pump, the hydrogen flow rate requirements for the stack under different operating conditions can be met. This can avoid the situation where the low ejector reflux pressure ratio under low operating conditions leads to insufficient gas entering the stack, thereby affecting the electrochemical reaction inside the fuel cell stack and reducing the efficiency of the fuel cell system.

[0062] In another embodiment, the hydrogen circulation pump can be replaced by a hydrogen ejector and hydrogen spray.

[0063] S3, constructing a gas-liquid separator model;

[0064] The gas-liquid separator is used to condense and separate the water vapor in the gas discharged from the anode outlet to prevent the water vapor from returning to the fuel cell stack after being pressurized by the hydrogen circulation pump, resulting in water flooding at the entrance of the fuel cell stack, causing the voltage of the first section or the first few sections of the fuel cell stack to be low, thereby affecting the overall efficiency of the fuel cell system. In this embodiment, the evaporation condensation cavity model for gas-water separation is selected in the AMEsim software. The model can define the component relationship between the anode outlet gas and water vapor and the relative humidity of the medium:

[0065] Relative humidity (%) = 100;

[0066] in, is the partial pressure of water vapor in a gas mixture, Represents the saturated vapor pressure at a given temperature. The model calculates the relative humidity based on the internal temperature of the condenser. When the relative humidity ratio reaches 100%, the water vapor condenses. The model removes the excess water to obtain 100% relative humidity. The condensed water enters the water storage box of the gas-liquid separator. The liquid level is monitored by the liquid level sensor in the water storage box to determine whether to open the drain valve for drainage.

[0067] S4, constructing a drain valve model;

[0068] In this embodiment, the drain valve selects a 2-port 2-position hydraulic valve model in the AMEsim software, and controls its valve opening time and valve opening angle through signal input.

[0069] S5, constructing a switch valve model;

[0070] The switch valve serves to cut off the hydrogen. When the switch valve is opened, the hydrogen enters the fuel cell system through the source. When the switch valve is closed, the high-pressure hydrogen in the source will not leak into the system, causing the internal pressure of the stack to be too high. In this embodiment, a two-way solenoid valve model for gas mixture application is selected in the AMEsim software. During the simulation operation, the switch valve is in the normally open state, and the internal diameter of the switch valve can be input.

[0071] S6, constructing a proportional valve model;

[0072] The proportional valve regulates the pressure and flow of hydrogen entering the fuel cell stack and is a pressure stabilizing device for the fuel cell system. In this embodiment, a two-way solenoid valve model for gas mixture application is selected in the AMEsim software. The model is calculated by a constant flow coefficient, so the model needs to input the throttle hole area and flow coefficient when the actual solenoid valve is fully opened, and the pressure and flow value entering the stack are adjusted by PID.

[0073] S7, constructing a nitrogen exhaust valve model;

[0074] In a normal state, the fuel cell system is introduced with air to allow oxygen in the air to participate in the electrochemical reaction, which causes nitrogen and other components in the air that do not participate in the reaction to accumulate in the cathode chamber of the fuel cell stack. Due to the concentration difference, the residual nitrogen in the stack will gradually diffuse to the anode side, thereby affecting the electrochemical reaction. Therefore, the anode side needs to discharge nitrogen periodically out of the system through a nitrogen exhaust valve. In this embodiment, a two-way solenoid valve model for gas mixture application is selected in the AMEsim software.

[0075] In another embodiment, the drain valve and the nitrogen exhaust valve can be integrated on the gas-liquid separator and used simultaneously. When the anode gas is discharged, it can first pass through the gas-liquid separator and then pass through the drain valve and the nitrogen exhaust valve.

[0076] The periodic switching of the nitrogen exhaust valve and the water discharge valve cooperates with the proportional valve at the hydrogen inlet end of the fuel cell stack to stabilize the hydrogen inlet pressure.

[0077] S8. construct a hydrogen heater model;

[0078] The high-temperature and high-humidity recirculated anode exhaust gas of the fuel cell is mixed with the dry and low-temperature new hydrogen from the hydrogen bottle. Due to the temperature difference, the water vapor in the recirculated anode exhaust gas condenses into liquid water droplets and enters the fuel cell stack, resulting in low voltage of the first section or the first few single cells in the fuel cell stack, resulting in poor overall performance of the fuel cell system. The hydrogen heater uses liquid cooling to heat the new hydrogen entering the fuel cell stack, and controls the temperature of the hydrogen entering the stack by controlling the coolant flow. In this embodiment, two half-heat exchanger models are selected in the AMEsim software, and heat is exchanged between the two heat exchanger modules through a heat exchanger. The actual heat exchanger mass and material are input to achieve the purpose of heating the new hydrogen. In another embodiment, the coolant flow of the hydrogen heater can be supplied by the fuel cell system or the whole vehicle.

[0079] S9. Based on the working principle of the hydrogen supply subsystem of the fuel cell, the models of the fuel cell stack, hydrogen heater, hydrogen circulation pump, switch valve, proportional valve, gas-liquid separator, drain valve and nitrogen exhaust valve are combined together to build a simulation model of the hydrogen supply subsystem based on AMEsim software.

[0080] By combining all the above models, a complete simulation model of the hydrogen supply subsystem based on AMEsim software is built. Figure 4 This is a simulation model diagram of the fuel cell hydrogen supply subsystem of the present invention, specifically:

[0081] The hydrogen heater model 7 is connected to the anode inlet of the fuel cell stack model 1 through the switch valve model 2 and the proportional valve model 3 in sequence; one end of the gas-liquid separator model 4 is connected to the anode outlet of the fuel cell stack model 1, and the other end of the gas-liquid separator model 4 is connected to the drain valve model 6; the hydrogen circulation pump 8 is connected between the outlet end of the gas-liquid separator 4 and the anode inlet of the fuel cell stack model 1; the nitrogen exhaust valve 5 is connected to the anode outlet of the fuel cell stack model 1. In addition, the anode inlet and anode outlet of the fuel cell stack model 1 are respectively provided with a pressure sensor, a temperature sensor, and a humidity sensor to monitor the pressure, temperature, and humidity of the stack, respectively. A controller of the proportional valve is provided between the proportional valve model 3 and the pressure sensor provided at the anode inlet, and the proportional valve model is simulated and controlled based on the pressure value of the pressure sensor.

[0082] Based on the above hydrogen supply subsystem model, the strategy of hydrogen inlet temperature and inlet pressure of the fuel cell system hydrogen supply subsystem can be verified and optimized, saving a lot of manpower and testing time.

[0083] like Figure 4 As shown, the high-pressure gas source outputs hydrogen, and its outlet pressure can be input according to the actual gas source pressure, and its inlet temperature is the ambient temperature. The hydrogen is heated by liquid cooling through the hydrogen heater model, and the coolant temperature in the hydrogen heater model is set as a variable to simulate the change of the coolant temperature in the system over time. The temperature entering the stack is monitored through the hydrogen inlet temperature monitoring point, so as to control the coolant flow of the hydrogen heater, and then control the gas inlet temperature to meet the hydrogen inlet temperature requirements, thereby improving the electrochemical reaction efficiency in the fuel cell stack. The heated hydrogen passes through the switch valve and then the proportional valve to reduce pressure and regulate the voltage before entering the fuel cell stack. There are pressure sensors, temperature sensors and humidity sensors at the entrance of the fuel cell stack to monitor the pressure, temperature and humidity of the stack respectively. The reacted gas (unreacted hydrogen, nitrogen, water vapor, etc.) is discharged through the anode outlet. One part is periodically discharged from the system through the nitrogen exhaust valve, and the other part is separated from the water by the gas-liquid separator model, and then the pressure is increased by the hydrogen circulation pump model, so that the recycled hydrogen is mixed with the new hydrogen and enters the fuel cell stack model to participate in the electrochemical reaction, and the separated liquid water is periodically discharged from the system through the drain valve model. The opening of the drain valve model is controlled by the liquid level height of the water storage box on the front-end gas-liquid separator, and the liquid level height of the water storage box is controlled by the liquid level sensor on the water storage box. The liquid level height of the water storage box is set to H1 when the drain valve is opened, and the liquid level height of the water storage box is set to H2 when the drain valve is closed. The drain valve is opened to ensure that no gas is discharged from the drain valve during the drainage process. When the liquid level sensor in the water storage box detects that the liquid level is H, if H>H1 at this time, the drain valve opens; after the drain valve is opened, when the liquid level sensor detects that the liquid level is H2, the drain valve closes.

[0084] The anode inlet pressure of the fuel cell system is controlled by proportional valve PID regulation. However, due to the inaccuracy of PID regulation parameters under different operating conditions, the hydrogen inlet pressure fluctuates greatly. This model considers a hydrogen inlet pressure stabilization strategy, such as Figure 5 As shown, it specifically includes: firstly, the preset pressure of hydrogen under different system working conditions is given, and the preset hydrogen pressure value under different operating conditions is set to P1, corresponding to the actual hydrogen inlet pressure P2 and the air inlet pressure P3. Firstly, the difference between the air inlet pressure P3 and the preset hydrogen pressure P1 is obtained. , the difference between the air inlet pressure P3 and the hydrogen inlet pressure P2 is obtained ,contrast and Value size. > , then the output value M, the value M adjusts the proportional coefficient, integral time and differential time of the PID controller of the proportional valve, thereby adjusting the duty cycle of PWM, and then controlling the opening of the proportional valve, reducing the fluctuation value of the hydrogen inlet pressure at each operating point, and playing a role in stabilizing the inlet pressure; if ≤ , then the output value N, the value N also adjusts the proportional coefficient, integral time and differential time of the PID controller of the proportional valve, thereby adjusting the duty cycle of PWM, controlling the opening of the proportional valve, and then reducing the fluctuation value of the hydrogen inlet pressure at each operating point, thereby stabilizing the inlet pressure.

[0085] Figure 6 It is the hydrogen inlet pressure value at a certain operating point of a certain power hydrogen fuel cell system simulated by AMEsim software. It can be seen from the figure that the fluctuation value of hydrogen inlet pressure is less than 1kPa. Figure 7 This is a comparison chart between the hydrogen inlet pressure at a certain operating point of a certain power hydrogen fuel cell system simulated by AMEsim software and the actual value. Figure 8 This is a comparison chart between the hydrogen inlet temperature at a certain operating point of a certain power hydrogen fuel cell system simulated by AMEsim software and the actual value.

[0086] The above-mentioned embodiment realizes the construction of a complete model of the fuel cell hydrogen supply subsystem, realizes the control of the hydrogen circulation pump speed, proportional valve opening, drain valve, nitrogen exhaust valve, and hydrogen heater, realizes the control of the inlet pressure, temperature and humidity value of the hydrogen supply subsystem, realizes the precise control of the inlet flow and pressure under different working conditions, and realizes that the fuel cell system can reach a stable state in a short time.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fuel cell hydrogen supply subsystem modeling method, characterized in that: The method comprises: In the AMEsim software, a fuel cell stack model, a hydrogen circulation pump model, a gas-liquid separator model, a drain valve model, a switch valve model, a proportional valve model, a nitrogen exhaust valve model and a hydrogen heater model are selected; the fuel cell stack model is a built-in stack model of the AMEsim software; the stack model is a multi-physics field model, which uses an electrochemical parameter fitting tool to evaluate the electrochemical reaction material consumption, hydrogen consumption, stack heating value, mass flow, pressure, temperature and humidity parameter monitoring and control of the fuel cell system; the hydrogen circulation pump model is a hydrogen circulation pump model for gas mixture applications in the AMEsim software, which can meet the hydrogen inlet flow requirements under different working conditions by controlling the speed of the hydrogen circulation pump; the gas-liquid separator model It is an evaporation condensation chamber model for gas-water separation in AMEsim software; the drain valve model is a 2-port 2-position hydraulic valve model in AMEsim software, and its valve opening time and valve opening angle are controlled by signal input; the switch valve model is a two-way solenoid valve model for gas mixture application in AMEsim software; the proportional valve model is a two-way solenoid valve model for gas mixture application in AMEsim software; the nitrogen exhaust valve model is a two-way solenoid valve model for gas mixture application in AMEsim software; the nitrogen exhaust valve and the drain valve periodically switch in coordination with the proportional valve at the hydrogen inlet end of the fuel cell stack, thereby achieving the function of stabilizing the hydrogen inlet pressure; the hydrogen heater model is a two-and-a-half heat exchanger model in AMEsim software; The hydrogen heater model is connected to the anode inlet of the fuel cell stack model through the switch valve model and the proportional valve model in sequence; one end of the gas-liquid separator model is connected to the anode outlet of the fuel cell stack model; the other end of the gas-liquid separator model is connected to the drain valve model; the hydrogen circulation pump is connected between the outlet end of the gas-liquid separator and the anode inlet of the fuel cell stack model; and the nitrogen exhaust valve is connected to the anode outlet of the fuel cell stack model.

2. A fuel cell hydrogen supply subsystem modeling method according to claim 1, characterized in that: Also includes: A pressure sensor, a temperature sensor and a humidity sensor are respectively arranged at the anode inlet and the anode outlet of the fuel cell stack model to monitor the pressure, temperature and humidity of the fuel cell stack respectively.

3. A fuel cell hydrogen supply subsystem modeling method according to claim 1, characterized in that: Also includes: A controller of the proportional valve is arranged between the proportional valve model and the pressure sensor arranged at the anode inlet; The controller is a PID controller.

4. A fuel cell hydrogen supply subsystem modeling method according to claim 1, characterized in that: Select the fuel cell stack model in AMEsim software, including: The battery stack model included in the AMEsim software is selected, and the air subsystem model and the thermal management subsystem model in the battery stack model are simplified; Adjust the hydrogen chamber pressure drop parameters according to different operating conditions of the fuel cell stack.

5. A fuel cell hydrogen supply subsystem modeling method according to claim 1, characterized in that: Hydrogen ejectors and hydrogen sprays are used instead of hydrogen circulation pumps.

6. A fuel cell hydrogen supply subsystem modeling method according to claim 1, characterized in that: The drain valve and nitrogen exhaust valve are integrated on the gas-liquid separator and used simultaneously.

7. A simulation control method for a fuel cell hydrogen supply subsystem, characterized in that: A fuel cell hydrogen supply subsystem model constructed by the fuel cell hydrogen supply subsystem modeling method according to any one of claims 1 to 6; The high-pressure gas source outputs hydrogen to the hydrogen heater model. The outlet pressure of the high-pressure gas source is input according to the actual gas source pressure, and the inlet temperature of the high-pressure gas source is the ambient temperature. Hydrogen is heated by liquid cooling through the hydrogen heater model. The coolant temperature in the hydrogen heater model is set as a variable to simulate the change of the coolant temperature in the system over time. The temperature entering the stack is monitored through the hydrogen inlet temperature monitoring point, thereby controlling the coolant flow of the hydrogen heater, and then controlling the gas inlet temperature to meet the hydrogen inlet temperature requirements, thereby improving the electrochemical reaction efficiency in the fuel cell stack; The heated hydrogen passes through the switch valve model and then the proportional valve model to reduce pressure, regulate and stabilize the pressure before entering the fuel cell stack model. The pressure sensor, temperature sensor and humidity sensor at the anode inlet of the fuel cell stack model monitor the pressure, temperature and humidity of the stack respectively. The gas after the reaction is discharged through the anode outlet of the fuel cell stack model. Part of it is periodically discharged from the system through the nitrogen exhaust valve model, and the other part is separated from the water by the gas-liquid separator model. It is then pressurized by the hydrogen circulation pump model to make the recycled hydrogen mixed with the new hydrogen and then enter the fuel cell stack model to participate in the electrochemical reaction. The separated liquid water is periodically discharged from the system through the drain valve model.

8. The simulation control method of a fuel cell hydrogen supply subsystem according to claim 7, characterized in that: The opening of the drain valve model is controlled by the liquid level height of the water storage box on the front-end gas-liquid separator, and the liquid level height of the water storage box is controlled by the liquid level sensor on the water storage box.

9. The simulation control method of a fuel cell hydrogen supply subsystem according to claim 8, characterized in that: The opening of the drain valve model is controlled by the liquid level height of the water storage box in the front-end gas-liquid separator, including: setting the liquid level height of the water storage box to H1 when the drain valve is opened, and the liquid level height of the water storage box to H2 when the drain valve is closed. When the liquid level sensor in the water storage box monitors the liquid level to be H, if H>H1 at this time, the drain valve is opened; after the drain valve is opened, when the liquid level sensor monitors the liquid level to be H2, the drain valve is closed.

10. The simulation control method of a fuel cell hydrogen supply subsystem according to claim 7, characterized in that: The control of the proportional valve model includes: Given the preset pressure of hydrogen under different system working conditions, the preset pressure of hydrogen under different operating conditions is set as P1, the corresponding actual hydrogen inlet pressure is P2, and the air inlet pressure is P3; The difference between the air inlet pressure P3 and the hydrogen preset pressure P1 is obtained , the difference between the air inlet pressure P3 and the hydrogen inlet pressure P2 is obtained ,contrast and Value size; when > , then the numerical value M is output, which controls the proportional coefficient, integral time and differential time of the PID controller of the proportional valve, adjusts the duty cycle of PWM, thereby controlling the opening of the proportional valve, reducing the fluctuation value of the hydrogen inlet pressure at each operating point, and playing a role in stabilizing the inlet pressure; like ≤ , then the output value N, the value N controls the proportional coefficient, integral time and differential time of the PID controller of the proportional valve, adjusts the duty cycle of PWM, thereby controlling the opening of the proportional valve, reducing the fluctuation value of the hydrogen inlet pressure at each operating point, and playing a role in stabilizing the inlet pressure.

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