Hydrogen fuel cell system for heavy-duty vehicles and control method

Abstract

The application discloses a hydrogen fuel cell system and a control method suitable for heavy trucks in plateau environment, comprising a hydrogen fuel cell system suitable for heavy trucks in plateau environment, air temperature and humidity control strategy, feedforward-feedback control strategy, temperature and power heat band demand temperature control strategy, optimal valve opening control strategy and cold start comprehensive strategy are constructed; at the same time, according to the physical terrain information of the current road of the vehicle, the energy demand control strategy under uphill and downhill working conditions is formulated, the heavy truck collaborative control strategy suitable for the plateau environment is constructed, and the adaptive control of the heavy truck is realized through the heavy truck collaborative control strategy. The application solves the technical problems of poor adaptability and insufficient operation efficiency of the hydrogen fuel cell heavy truck in the plateau environment.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell vehicle technology, and in particular to a heavy-duty vehicle hydrogen fuel cell system and control method suitable for high-altitude environments. Background Technology

[0002] As the nation continues to advance its "dual-carbon" strategic goals, the automotive industry is gradually incorporating the research and development of new energy vehicles into the key direction of ecological civilization construction. Hydrogen fuel cell vehicles use electricity generated from the electrochemical reaction of hydrogen as their power source. Hydrogen energy is widely available and has high energy conversion efficiency, giving it environmental and technological advantages in the transportation market.

[0003] In recent years, the government has encouraged the development of the hydrogen fuel cell vehicle industry. In March 2025, the Ministry of Industry and Information Technology and other departments issued the "Work Plan for Stabilizing Growth in the Automobile Industry (2025-2026)," which pointed out the need to orderly promote the construction of hydrogen energy infrastructure and accelerate the development of new energy vehicles. However, with the gradual promotion of hydrogen fuel cell vehicles in the passenger car market, their adaptability in extreme environments such as high altitudes and cold regions faces severe challenges. In cold environments, the starting performance of hydrogen fuel cells decreases, and in high-altitude environments, the large temperature difference between day and night leads to large temperature variations inside the battery. Moreover, the low hydrogen content can cause insufficient oxygen supply, resulting in reduced output power and energy efficiency.

[0004] To address these issues and promote the development of the hydrogen fuel cell vehicle industry, in January 2026, the Ministry of Industry and Information Technology revised the "Requirements for Access Review of Road Motor Vehicle Manufacturers," requiring vehicle manufacturers to conduct high-altitude environment reliability tests on newly submitted models for the following year. Therefore, it is necessary to design a hydrogen fuel cell heavy-duty vehicle suitable for high-altitude environments and its adaptive control method. By optimizing the vehicle's battery system structure and control strategy, the adaptability and operating efficiency of the vehicle in high-altitude environments can be improved. Summary of the Invention

[0005] This invention provides a heavy-duty vehicle hydrogen fuel cell system and control method suitable for high-altitude environments, in order to overcome the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments includes an air subsystem, a hydrogen subsystem, and a thermal management subsystem; The air subsystem includes a filter, an air compressor, a proportional valve, an intercooler, and a humidifier equipped with PID control, which are connected in sequence in the air inlet direction of the hydrogen fuel cell; a back pressure valve connected to the outside is provided in the air outlet direction of the hydrogen fuel cell. The air subsystem is used to provide oxygen for the chemical reaction of the hydrogen fuel cell. The hydrogen subsystem includes a hydrogen storage tank, a flow meter, a shut-off valve, a proportional valve, and a PTC heater connected sequentially in the hydrogen inlet direction of the hydrogen fuel cell. A first circulation pump is connected in the hydrogen outlet direction of the hydrogen fuel cell. The output end of the first circulation pump is connected to a second circulation pump, an exhaust valve, and a drain valve. The output end of the second circulation pump is connected to a pipeline between the heater and the hydrogen inlet of the hydrogen fuel cell. A heat tracing cable is installed on the pipeline from the hydrogen outlet of the fuel cell stack to the drain valve and the exhaust valve. The hydrogen subsystem is used to provide hydrogen for the chemical reaction of the hydrogen fuel cell and maintain the hydrogen inlet temperature and reduce the probability of icing in the hydrogen outlet pipeline through the PTC heater and the heat tracing cable. The thermal management subsystem includes a heating water pump and a coolant tank connected sequentially in the direction of the coolant inlet of the hydrogen fuel cell; the input end of the coolant tank is connected to one end of a second three-way valve, and the other two ends of the second three-way valve are respectively connected to the coolant outlet of the hydrogen fuel cell and one end of a first three-way valve through pipelines; the other two ends of the first three-way valve are respectively connected to one end of the vehicle body heat exchanger and one end of the radiator; the other end of the vehicle body heat exchanger and the other end of the radiator are connected to the pipeline between the second three-way valve and the coolant tank. The thermal management subsystem is used to control the temperature of the coolant in the hydrogen fuel cell, thereby achieving temperature control of the hydrogen fuel cell stack.

[0007] A control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments, comprising the following steps: S1: An air temperature and humidity control strategy based on the air subsystem, designed to compensate for heat transfer losses and prevent the decrease in water film humidity in a high-altitude environment. S2: Based on the hydrogen subsystem, a feedforward-feedback control strategy for the heater to maintain the hydrogen temperature and a temperature control strategy for the heating cable to reduce the probability of icing in the hydrogen outlet pipeline are constructed considering the high-altitude environment. S3: Based on the thermal management subsystem, an optimal valve opening control strategy is constructed to stabilize the temperature of the fuel cell stack and reduce heat loss in a high-altitude environment; at the same time, a comprehensive cold start strategy for the hydrogen fuel cell is formulated by constructing a coolant-assisted heating strategy, a liquid water purging strategy, and an adaptive start-up current control strategy. S4: After the fuel cell starts up and operates stably, a lookup table control strategy is constructed by combining real-time map altitude information. This strategy takes altitude and stack power demand as inputs and the optimal oxygen supply ratio as outputs. The lookup table control strategy can infer the overall pressure ratio of the air compressor based on altitude. Meanwhile, the back pressure valve opening is adjusted based on empirical values ​​to achieve operation control of the air subsystem; at the same time, an energy demand control strategy based on altitude is constructed, which is used to obtain the actual driving power demand corresponding to the vehicle being in uphill or downhill conditions. S5: Based on steps S1 to S4, construct a cooperative control strategy for heavy-duty vehicles suitable for high-altitude environments, and achieve adaptive control of heavy-duty vehicles through the cooperative control strategy.

[0008] Furthermore, the air temperature and humidity control strategy described in S1 is specifically as follows: S11: After air passes through the filter and air compressor, and is regulated by the proportional valve, it comes into contact with the heat sink in the intercooler. The heat exchange capacity of the heat sink is determined by the heat transfer... and the overall heat transfer coefficient related to altitude Obtain the required area of ​​the heat sink. for:

[0009]

[0010] In the formula: This represents the logarithmic mean temperature difference; This indicates the inlet and outlet temperatures of the intercooler; , This indicates the inlet and outlet temperatures of the coolant. S12: Based on PID control technology, the humidity of the air output from S11 is adjusted, and the control law for the humidifier's humidification capacity adjustment signal is constructed as follows:

[0011] In the formula: This indicates the proportional gain, which is the amplification factor of the humidity deviation. This indicates that the integral gain reduces the humidity deviation under steady-state conditions. This represents the differential gain, which reduces the overshoot caused by humidity changes. Indicates the current humidity of the water film. With target humidity Deviation; This indicates the output of the humidifier, i.e., the humidification adjustment signal; Indicates time parameters; express The abbreviated form of .

[0012] Furthermore, the feedforward-feedback control strategy constructed in S2 is specifically as follows: S21: The heat loss model for the PTC heater is established as follows:

[0013] In the formula: Indicates heat loss; This represents the heat transfer coefficient between the PTC heater and the external environment; This indicates the heat dissipation area of ​​the PTC heater; Indicates ambient temperature; This indicates the core temperature of the PTC heater; S22: Obtain the hydrogen inlet temperature of the fuel cell, and construct the feedforward heating power of the PTC heater by setting the target hydrogen heating temperature and combining it with the heat loss model:

[0014]

[0015] In the formula: Indicates the feedforward heating power; This indicates the mass flow rate of hydrogen entering the hydrogen subsystem from the hydrogen storage tank. This indicates the specific heat capacity of hydrogen. This indicates the set target temperature for hydrogen heating; This indicates the hydrogen inlet temperature of the fuel cell; This indicates the power consumed by the PTC heater during its operation due to heat loss. Indicates the heat loss coefficient of the heater; Obtain the temperature deviation caused by the feedforward heating power. After correction, the resulting deviation in heating power is:

[0016] In the formula: Indicates the deviation in heating power; The proportional gain represents the deviation in heating power; The integral gain represents the deviation heating power; S23: Based on the feedforward heating power and the deviation heating power, the expected heating power of the PTC heater is obtained as follows:

[0017] In the formula: Indicates the desired heating power; These represent the minimum and maximum values ​​of the heating power within the corresponding safety constraint range, respectively. express The abbreviated form of .

[0018] Furthermore, the specific temperature control strategy for the electric heating tape described in S2 is as follows: S24: Obtain the heating power of the electric heating tape based on its resistance. for:

[0019] In the formula: This indicates the voltage of the electric heating tape. This indicates that the electric heating cable has a temperature of [temperature value missing]. The resistance below; This indicates the temperature coefficient of the electric heating tape; Indicates reference temperature; S25: Based on the heating power of the electric heat tracing tape The heat balance model for the hydrogen outlet pipeline is as follows:

[0020]

[0021] In the formula: This indicates the heat dissipation capacity of the hydrogen outlet pipeline; This represents the heat transfer coefficient of the hydrogen outlet pipeline; This indicates the cross-sectional radius of the hydrogen outlet pipeline; S26: The exponent term is simplified using a first-order Taylor expansion. Substitute this into the heat balance model to solve for the required temperature of the electric heating cable:

[0022] In the formula: This indicates that the electric heating cable is at the reference temperature. The resistance below; Indicates ambient temperature.

[0023] Furthermore, the optimal valve opening control strategy in S3 is as follows: S31: Establish information about the heat generated by the fuel cell stack Heat carried away by the coolant and heat loss The energy balance equation between them is:

[0024]

[0025]

[0026]

[0027] In the formula: Indicates the heat capacity of the fuel cell stack; Indicates the temperature of the fuel cell stack; Indicates the mass of coolant; Indicates the heat capacity of the coolant; , These represent the temperatures of the coolant at the fuel cell outlet and inlet, respectively. Indicates the current in the fuel cell stack; This represents the thermodynamic voltage of the fuel cell stack. Indicates the stack voltage; Indicates the first The valve opening of a three-way ball valve; This indicates the temperature of the coolant after passing through the vehicle body heat exchanger and radiator. S32: Based on the energy balance equation, construct a sequence for solving and obtaining the optimal valve opening control sequence. The quadratic programming model is as follows:

[0028] In the formula: This indicates the location of the pipes containing the heat exchanger and radiator in the vehicle body. k The valve opening at any given moment; Indicates the length of the prediction time domain; Indicates the temperature of the fuel cell stack; Indicates in k Time prediction k + j The temperature of the fuel cell stack at any given time; Indicates the target operating temperature of the fuel cell stack; This indicates the heat required for the dye-coated battery to operate; This indicates the heat required for the vehicle body to operate.

[0029] Furthermore, the comprehensive cold-start strategy for hydrogen fuel cells formulated in S3 is as follows: S33: Construct a coolant-assisted heating strategy: When the current ambient temperature is detected to be below 0°C, the coolant flowing out of the coolant tank and into the hydrogen fuel cell is heated by a heating water pump. When the temperature of the coolant reaches the first temperature threshold, the first three-way ball valve is shut off, and the pipeline between the coolant and the vehicle heat exchanger and radiator is closed by a pre-set valve. The heating power of the heating water pump for:

[0030] In the formula: This represents the proportional gain of the heating power of the water pump. The integral gain represents the heating power of the water pump. Indicates the target temperature of the coolant; Simultaneously, a constructed liquid water purging strategy is implemented: during the cold start phase when the ambient temperature is below 0°C, while executing the coolant-assisted heating strategy, hydrogen purging is performed by controlling the drain and exhaust valves of the hydrogen system to remove liquid water from its internal flow channels; and the purging mass flow rate of the liquid water purging strategy is... With purging time satisfy:

[0031] In the formula: Indicates the volume of the anode flow channel in a fuel cell; , This indicates the initial hydrogen concentration and the safe hydrogen concentration within the anode flow channel of the fuel cell; Constructing an adaptive start-up current control strategy: Calculating and obtaining the ice integral of proton exchange membrane icing inside the fuel cell. for:

[0032] In the formula: express The abbreviated form; This represents the defined integral function; Indicates the insulation resistance of the fuel cell; And based on ice integral Combined with battery temperature Constructing the starting current of the fuel cell The control law is:

[0033] In the formula: This represents the initial current of the fuel cell; This indicates the temperature rise coefficient of the fuel cell; Indicates the temperature threshold; Indicates the ice integral threshold; Indicates the current starting current; S34: When the temperature of the coolant is detected to reach the second temperature threshold, the heating water pump is stopped and the hydrogen fuel cell system is put into normal operation, thereby realizing the cold start of the hydrogen fuel cell vehicle.

[0034] Furthermore, the lookup table control strategy constructed in S4 is specifically as follows: S41: Obtain real-time map elevation information and calculate oxygen partial pressure based on current atmospheric pressure. for:

[0035] In the formula: Indicates the current altitude The atmospheric pressure below; This indicates the percentage of oxygen partial pressure. S42: Based on the partial pressure of oxygen When air passes through the air compressor of the air subsystem in the fuel cell system, the oxygen pressure at the air inlet of the fuel cell increases to [a certain value]. :

[0036] In the formula: This indicates the overall pressure ratio at which the air compressor operates; This indicates the increased oxygen pressure. S43: Based on the increased oxygen pressure Obtain the maximum available oxygen mass flow rate for:

[0037] In the formula: The proportion coefficient representing oxygen; This indicates the partial pressure of oxygen within the cathode channel of the fuel cell stack; The gas constant representing oxygen; S44: Considering the impact of oxygen supply on battery power, based on steps S41 to S43, a lookup table control strategy is defined, with altitude and stack power demand as inputs and the optimal oxygen supply ratio as output:

[0038] In the formula: This indicates the optimal oxygen supply ratio; This represents a table lookup function; This indicates the battery power demand related to oxygen supply. The table lookup control strategy can use altitude as a basis to infer and obtain the overall pressure ratio of the air compressor. Meanwhile, the opening of the back pressure valve is adjusted based on empirical values ​​to achieve operation control of the air subsystem.

[0039] Furthermore, the energy demand control strategy based on altitude in S4 is as follows: S45: Based on the physical terrain information of the current road surface obtained by the onboard navigation system, establish the vehicle power demand of the hydrogen fuel cell vehicle. The model is:

[0040] In the formula: Indicates the vehicle's curb weight; Represents gravitational acceleration; Indicates the coefficient of rolling friction; Indicates the drag coefficient; Indicates the windward area; Indicates the current altitude Atmospheric density below; Indicates the vehicle's speed; Indicates the angle of inclination; S46: When the vehicle enters an uphill section, a control command is issued via a pre-set onboard controller to increase the output power of the fuel cell as follows:

[0041] In the formula: Indicates the uphill preloading time; The slope representing the battery's applied power; This indicates the output power ratio of the hydrogen fuel cell and the power battery; This indicates the output power required for the vehicle to go uphill; Indicates the initial time; express The maximum value; S47: When the vehicle enters a downhill slope, a control command is issued through a pre-set onboard controller to recover a portion of the vehicle's gravitational potential energy by converting it into electrical energy. This energy recovery process converts a portion of the gravitational potential energy into electrical energy and recharges the vehicle's battery. The energy recovery power is [not specified in the original text]. for:

[0042] In the formula: Indicates energy recovery efficiency; This indicates the maximum charging power of the power battery.

[0043] Furthermore, the heavy-duty vehicle cooperative control strategy developed in S5 for high-altitude environments is specifically as follows: S51: Confirm the current operating phase of the heavy-duty vehicle; The operation phases include the startup phase, normal operation phase, uphill phase, and downhill phase; If the running phase is confirmed to be the startup phase, then execute S52; If the operation phase is confirmed to be the normal operation phase, then execute S53; If the operation phase is confirmed to be an uphill phase, then execute S54; If the operation phase is confirmed to be a downhill phase, then execute S55; S52: When the ambient temperature is below 0℃, the cold start of the hydrogen fuel cell vehicle is achieved by executing the cold start integrated strategy in S3. At the same time, the temperature control strategy for the heating cable demand in S2 is executed to reduce the probability of icing in the hydrogen outlet pipeline. S53: Based on the current environmental conditions and vehicle status, obtain the vehicle's required power through S45. The system obtains real-time map elevation information and uses a lookup table-based control strategy to infer the overall pressure ratio of the air compressor based on the elevation. Furthermore, the back pressure valve opening is adjusted based on empirical values ​​to achieve operation control of the air subsystem; at the same time, under the premise of meeting the stack temperature in the fuel cell, the optimal valve opening control strategy is executed to stabilize the stack temperature in the hydrogen fuel cell and reduce heat loss; in addition, the hydrogen temperature in the hydrogen subsystem is maintained by executing the constructed feedforward-feedback control strategy, and the air temperature and humidity control strategy is also executed to compensate for air heat exchange loss in the air subsystem and prevent water film humidity from decreasing. S54: Based on S46, obtain the increased output power of the fuel cell, thereby achieving adaptive control operation of heavy-duty vehicles; S55: Energy recovery power based on S47 Energy is recovered during vehicle operation to achieve adaptive control of heavy-duty vehicles.

[0044] Beneficial Effects: This invention provides a heavy-duty vehicle hydrogen fuel cell system and control method suitable for high-altitude environments. Based on the established heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments, an air temperature and humidity control strategy, a feedforward-feedback control strategy, a heating cable demand temperature control strategy, an optimal valve opening control strategy, and a cold start comprehensive strategy are constructed. Simultaneously, based on the physical terrain information of the current road, energy demand control strategies for uphill and downhill conditions are formulated. Finally, this invention constructs a heavy-duty vehicle cooperative control strategy suitable for high-altitude environments, achieving adaptive control of the heavy-duty vehicle and significantly improving the adaptability and operating efficiency of hydrogen fuel cell heavy-duty vehicles in high-altitude environments. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a flowchart of the control method for a heavy-duty vehicle hydrogen fuel cell system applicable to high-altitude environments according to the present invention. Figure 2 This is a structural diagram of the power system of the hydrogen fuel cell heavy-duty vehicle in this embodiment; Figure 3 This is a schematic diagram of the hydrogen fuel cell stack in this embodiment; Figure 4 This is a structural diagram of the fuel cell system of the hydrogen fuel cell heavy-duty vehicle in this embodiment. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] This embodiment provides a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments, such as... Figure 4 As shown, it includes an air subsystem, a hydrogen subsystem, and a thermal management subsystem; The air subsystem includes a filter, air compressor, proportional valve, intercooler, and humidifier equipped with PID control, connected sequentially in the air inlet direction of the hydrogen fuel cell; a back pressure valve connected to the outside is provided in the air outlet direction of the hydrogen fuel cell. The air subsystem is used to provide oxygen for the chemical reaction of the hydrogen fuel cell. The hydrogen subsystem includes a hydrogen storage tank, flow meter, shut-off valve, proportional valve, and PTC heater connected sequentially in the hydrogen inlet direction of the hydrogen fuel cell; a first circulation pump is connected in the hydrogen outlet direction of the hydrogen fuel cell; the output end of the first circulation pump is connected to a second circulation pump, an exhaust valve, and a drain valve, respectively; and the output end of the second circulation pump is connected to the pipeline between the heater and the hydrogen inlet of the hydrogen fuel cell. Electric heat tracing is installed on the pipeline from the hydrogen outlet of the fuel cell stack to the drain valve and the exhaust valve. The hydrogen subsystem provides hydrogen for the chemical reaction in the hydrogen fuel cell and maintains the hydrogen inlet temperature and reduces the probability of icing in the hydrogen outlet pipeline through a PTC heater and a heat tracing cable. The thermal management subsystem includes a heating water pump and a coolant tank connected sequentially in the direction of the coolant inlet of the hydrogen fuel cell. The inlet of the coolant tank is connected to one end of a second three-way valve. The other two ends of the second three-way valve are connected to the coolant outlet of the hydrogen fuel cell and one end of a first three-way valve, respectively, through pipelines. The other two ends of the first three-way valve are connected to one end of a vehicle heat exchanger and one end of a radiator, respectively. The other end of the vehicle heat exchanger and the other end of the radiator are connected to the pipeline between the second three-way valve and the coolant tank. The thermal management subsystem controls the temperature of the coolant in the hydrogen fuel cell, thereby achieving temperature control of the hydrogen fuel cell stack.

[0049] Furthermore, this embodiment also includes a hydrogen fuel cell heavy-duty vehicle power system structure suitable for high-altitude environments, such as... Figure 2 As shown, its main structure and working principle are as follows: The hydrogen fuel cell converts the chemical energy of air and hydrogen from the storage tank into electrical energy through an electrochemical reaction. This electrical energy, along with that from the power battery, is processed by DC / DC and DC / AC units to drive the motor and transmission mechanism, which in turn rotates the wheels. In terms of automotive powertrain structure, a hydrogen fuel cell stack is proposed, referencing... Figure 3 The structure and working principle of the fuel cell stack are as follows: When the hydrogen fuel cell stack starts working, hydrogen from the hydrogen storage tank enters the bipolar plate from the anode side, while air enters the other bipolar plate via the cathode side and the air compressor. Then, hydrogen and air enter the anode and cathode channels respectively, and pass through the gas diffusion layer and catalyst layer. Hydrogen and oxygen undergo oxidation-reduction reactions to produce water and electricity. Regarding the fuel cell stack structure, a hydrogen fuel cell system suitable for high-altitude environments is proposed, referencing... Figure 4 The structure and working principle of its fuel cell system are as follows: The main structure includes an air system, a hydrogen system, and a thermal management system. The air system includes a filter, an air compressor, a proportional valve, an intercooler, a humidifier, and a back pressure valve and its components. The hydrogen system includes a shut-off valve, a proportional valve, a heater, a flow meter, and circulation pumps 1 and 2. The thermal management system includes a vehicle body heat exchanger, a radiator, a coolant tank, and a heating water pump and its components, which are responsible for cooling / heating the fuel cell to ensure its cold start and normal operation. Sensors are installed in the pipeline, with temperature sensors located at positions 3, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16; pressure sensors located at positions 1, 2, and 19; humidity sensors located at positions 4, 5, and 7; and concentration sensors located at positions 17 and 18. Each sensor transmits environmental and vehicle status data to the on-board controller via a CAN bus. In addition, the hydrogen fuel cell heavy-duty vehicle power system suitable for high-altitude environments is also equipped with an insulation resistance measurement device.

[0050] A control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments, such as Figure 1 As shown, the specific steps include: S1: An air temperature and humidity control strategy based on the air subsystem, considering high-altitude environments, to compensate for heat exchange losses and prevent water film humidity decline; specifically, in order to solve the problem of insufficient air intake caused by low pressure in high-altitude environments, this embodiment installs a piston-screw two-stage supercharged electric air compressor in the air subsystem to increase the air pressure to above 1.5MPa; at the same time, in order to prevent the vehicle's heat exchange efficiency from decreasing, the heat exchange area of ​​the intercooler can be increased and a PID-controlled humidifier and an electronic back pressure valve with a ball valve core are installed to ensure that the air pressure, temperature, and humidity meet the requirements of the fuel cell stack, specifically including: By installing a piston-screw two-stage booster electric air compressor in the air subsystem, the air pressure at the fuel cell inlet is increased in high-altitude areas. The specific technical solution is as follows: the first stage of the electric air compressor uses a piston structure, and the second stage uses a screw structure. When air enters the first-stage booster structure through a filter, the moving piston increases the air pressure to above 0.5 MPa before it enters the second-stage booster. The screw rotor continues to rotate. After the action of the piston-screw two-stage booster air compressor, the overall pressure ratio of the air compressor is [insert pressure here]. (Defined as the ratio of the absolute pressure at the outlet of the second-stage helical rotor to the absolute pressure at the inlet of the first-stage piston structure) This ensures that the air pressure detected at pressure sensor 2 reaches above 1.5 MPa, resulting in a relatively stable high-pressure airflow. This allows the air supply requirements of the fuel cell to still be met even when the inlet air pressure is ≤80 kPa.

[0051] Then, in this embodiment, an air temperature and humidity control strategy is constructed to compensate for heat transfer losses and prevent the water film humidity from decreasing, specifically as follows: S11: After air passes through the filter and air compressor, and is regulated by the proportional valve, it comes into contact with the heat sink in the intercooler, where heat exchange occurs. Due to the area of ​​the heat sink Logarithmic mean temperature difference Regarding this, according to current experimental studies on the relationship between altitude and equipment heat transfer efficiency, the overall heat transfer coefficient increases by 1000m for every 1000m increase in altitude. The temperature will drop by 2-3%, therefore, considering the altitude at which current vehicles are designed, the original heat sink area needs to be reduced. Increase by 10-15%. This depends on the heat exchange capacity of the heat sink. and the overall heat transfer coefficient related to altitude Obtain the required area of ​​the heat sink. for: (1) (2) In the formula: This represents the logarithmic mean temperature difference; This indicates the inlet and outlet temperatures of the intercooler; , This indicates the coolant inlet and outlet temperatures; in this embodiment, increasing the radiator area can effectively alleviate the overall heat transfer coefficient. The decrease in temperature leads to a reduction in heat dissipation. In addition to ensuring heat exchange, it's also necessary to control air humidity. This is because the air after passing through the intercooler enters the humidifier, where it comes into contact with the air through a water film and conducts heat. Therefore, to prevent the water film from losing humidity under the high temperature and pressure of the flowing gas, a humidifier is needed to maintain the humidity of the water film.

[0052] The amount of water evaporation on the surface of the water film With water vapor concentration difference Related, described as: (3) in, Indicates the heat transfer coefficient of water vapor. Indicates the area of ​​the water film. The saturated water vapor density at the surface of the water film. The density of water vapor in air; the humidity of the air that the intercooler needs to handle is higher than that of the air in the air in the water vapor density. for: (4) in, , This indicates the humidity ratio between the outlet and inlet of the intercooler. This indicates the mass of water vapor in the air inside the intercooler, while the humidity ratio is related to the relative humidity. The relationship is described as follows: (5) in, This indicates the total gas pressure inside the intercooler. Indicates saturated vapor pressure; S12: According to formulas (3) to (5), controlling humidity means controlling the evaporation of the water film, that is, the current humidity of the water film. With target humidity deviation Therefore, in order to control the humidity of the water film surface in this embodiment, PID control technology is used to construct a control law for the humidification amount adjustment signal of the humidifier as follows: (6) In the formula: This indicates the proportional gain, which is the amplification factor of the humidity deviation. This indicates that the integral gain reduces the humidity deviation under steady-state conditions. This represents the differential gain, which reduces the overshoot caused by humidity changes. Indicates the current humidity of the water film. With target humidity Deviation; This indicates the output of the humidifier, i.e., the humidification adjustment signal; Indicates time parameters; express The abbreviated form of .

[0053] Furthermore, this embodiment employs an electronic back pressure valve with a spherical valve core to control the air outlet pressure of the fuel cell. The back pressure valve controls the air outlet pressure of the fuel cell by controlling the air outlet pressure of the fuel cell through a valve with a radius of... The ball valve core moves up and down to control the gas flow in the pipeline. When the valve is at its small to large opening, the flow height... With valve core displacement The relationship is: (7) in, The geometric coefficient related to the contact angle between the valve core and the valve seat, and the flow area. Represented as: (8) Equation (7) represents the circulation area. With valve core displacement The relationship is linear. When the fuel cell is operating stably or at low power, the on-board controller controls the opening of the back pressure valve, i.e., the effective flow area. At this time, air mass flow rate for: (9) in, The air density at the inlet of the back pressure valve. This refers to the airflow velocity at the inlet of the back pressure valve. When the fuel cell is operating under high load, the back pressure valve operates in a supercritical state, and the air mass flow rate... for: (10) in, This refers to the air pressure at the inlet of the back pressure valve. In this embodiment, the air mass flow rate at the battery cathode inlet will be realized. With battery consumption Back pressure valve discharge air mass flow rate The balance between them is described as: (11) in, This refers to the air pressure at the outlet of the back pressure valve. This refers to the volume of the cathode flow channel in the battery.

[0054] S2: Based on the hydrogen subsystem, a feedforward-feedback control strategy for the heater to maintain the hydrogen temperature and a temperature control strategy for the heating cable to reduce the probability of icing in the hydrogen outlet pipeline are constructed considering the high-altitude environment. The feedforward-feedback control strategy constructed in this embodiment is specifically as follows: S21: By adding a controllable PTC heater in the pipeline after the shut-off valve and proportional valve of the hydrogen system, the inlet temperature of the hydrogen is increased. The controllable PTC heater added in this embodiment uses a temperature sensor with a high response speed, ensuring that the temperature of the hydrogen entering the fuel cell stack after heating is maintained between (5-15)°C. The heat generated by the heater is equal to the heat required for heating the hydrogen and the heat of the heater equipment. and heat lost to the environment To reach equilibrium, described as (12) in, This indicates the mass flow rate of hydrogen entering the hydrogen system from the hydrogen storage tank. This refers to the specific heat capacity of hydrogen. , These are the hydrogen temperatures at the heater inlet and outlet, respectively. This refers to the heat capacity between the heater core and adjacent piping. Let be the temperature of the heater core. Equation (12) establishes the dynamic thermal equilibrium relationship of the heater, where the heat loss is... This is a key variable affecting the heater's performance. In this embodiment, to accurately calculate the heat loss during the heater's heating of hydrogen, it is necessary to further establish a quantitative relationship between this loss and the heater temperature and ambient temperature; that is, to establish a heat loss model for the PTC heater as follows: (13) In the formula: Indicates heat loss; This represents the heat transfer coefficient between the PTC heater and the external environment; This indicates the heat dissipation area of ​​the PTC heater; Indicates ambient temperature; This indicates the core temperature of the PTC heater; In this embodiment, after obtaining the heat loss model, a feedforward-feedback control strategy for the heater is constructed: First, before the heater heats the hydrogen in the pipeline, the target temperature for hydrogen heating needs to be set according to the ambient temperature of the vehicle and the vehicle's status. The specific situation is as follows: (1) When the vehicle is cold-started or the ambient temperature is below 0°C, the target temperature will be set to 0°C. (1) Set the temperature to between (5-15)℃; (2) When the vehicle is running normally or the ambient temperature is between (0-25)℃, set the target temperature. Set the temperature to between (8-10)℃; (3) When the vehicle is located in an area with an altitude of over 3000m, set the target temperature to... Increase the current temperature by (2~3)℃. Then, adjust according to the set target temperature. The power of the heater is controlled by PI control. Feedforward heating power and deviation heating power Composition, specifically: S22: Obtain the hydrogen inlet temperature of the fuel cell, and construct the feedforward heating power of the PTC heater by setting the target hydrogen heating temperature and combining it with the heat loss model: (14) (15) In the formula: Indicates the feedforward heating power; This indicates the mass flow rate of hydrogen entering the hydrogen subsystem from the hydrogen storage tank. This indicates the specific heat capacity of hydrogen. This indicates the set target temperature for hydrogen heating; This indicates the hydrogen inlet temperature of the fuel cell; This indicates the power consumed by the PTC heater during its operation due to heat loss. Indicates the heat loss coefficient of the heater; Obtain the temperature deviation caused by the feedforward heating power. After correction, the resulting deviation in heating power is: (16) In the formula: Indicates the deviation in heating power; The proportional gain represents the deviation heating power; The integral gain represents the deviation heating power; S23: Based on the feedforward heating power and the deviation heating power, obtain the expected heating power of the PTC heater, i.e., by calculating the feedforward heating power. With deviation heating power The operating power of the heater Define the scope of safety constraints, described as follows: (17) In the formula: Indicates the desired heating power; These represent the minimum and maximum values ​​of the heating power within the corresponding safety constraint range, respectively. express The abbreviated form of .

[0055] The temperature control strategy for the electric heating cable described in this embodiment is as follows: S24: A heated heating tape is installed on the pipeline from the hydrogen outlet of the fuel cell stack to the drain valve and exhaust valve to reduce the probability of icing in the flow channel. The heated heating tape, made of conductive polymer, generates heat by adjusting its own resistance, thereby raising the temperature of the hydrogen outlet pipeline. Its resistance and description are as follows: (18) In the formula: This indicates that the electric heating cable has a temperature of [temperature value missing]. The resistance below, This indicates that the electric heating cable is at the reference temperature. The resistance below, This indicates the temperature coefficient of the electric heating tape; The heating power of the electric heating cable is obtained based on its resistance. for: (19) In the formula: This indicates the voltage of the electric heating tape. This indicates that the electric heating cable has a temperature of [temperature value missing]. The resistance below; S25: To prevent icing in the hydrogen outlet pipeline of the vehicle in the high-altitude, cold environment, a heating power requirement needs to be met. With pipeline heat dissipation power Achieving thermal balance, i.e., based on the heating power of the electric heating tape... The heat balance model for the hydrogen outlet pipeline is as follows: (20) (twenty one) In the formula: This indicates the heat dissipation capacity of the hydrogen outlet pipeline; The heat transfer coefficient of the hydrogen outlet pipeline is expressed in W / (m²·K). Indicates the cross-sectional radius of the hydrogen outlet pipeline; S26: In this embodiment, the heating temperature of the electric heating tape is required to be higher than the freezing point of the environment at that time. Linearization is achieved by using a first-order Taylor expansion, that is, by using a first-order Taylor expansion to simplify the exponential term to... Substitute this into the heat balance model to solve for the required temperature of the electric heating cable: (twenty two) In the formula: This indicates that the electric heating cable is at the reference temperature. The resistance below; Indicates ambient temperature.

[0056] This embodiment, after ensuring the quality of the gas supply entering the fuel cell stack in steps S1 to S2, uses MPC to control the opening of the three-way ball valve and the proportional valve to stabilize the temperature of the fuel cell stack and reduce heat loss. For high-altitude conditions where the temperature is below 0°C, a comprehensive strategy for subsequent cold-start control of the fuel cell stack is formulated: S3: Based on the thermal management subsystem, an optimal valve opening control strategy is constructed to stabilize the temperature of the fuel cell stack and reduce heat loss in a high-altitude environment; at the same time, a comprehensive cold start strategy for the hydrogen fuel cell is formulated by constructing a coolant-assisted heating strategy, a liquid water purging strategy, and an adaptive start-up current control strategy. The optimal valve opening control strategy in this embodiment is as follows: S31: In this embodiment, MPC is used to control the hydrogen fuel cell stack and its thermal management system, effectively managing the heat in the stack and thermal management system: the heat generated by the hydrogen fuel cell stack is dissipated into the coolant and the surrounding environment. First, a heat balance equation for the stack is established to measure the heat generated by the stack. Heat carried away by the coolant and heat loss The relationship between the heat generated by the fuel cell stack and the thermal balance equation is then established. Based on this equation, an MPC optimization problem is constructed to control the stack temperature by adjusting the opening of the coolant tank valve. Therefore, a method for calculating the heat generated by the fuel cell stack is established. Heat carried away by the coolant and heat loss The energy balance equation between them is: (twenty three) (twenty four) (25) In the formula: Indicates the heat capacity of the fuel cell stack; Indicates the temperature of the fuel cell stack; Indicates the mass of coolant; Indicates the heat capacity of the coolant; , These represent the temperatures of the coolant at the fuel cell outlet and inlet, respectively. Indicates the current in the fuel cell stack; This represents the thermodynamic voltage of the fuel cell stack; This represents the fuel cell stack voltage. In the thermal management subsystem, the coolant flowing from the fuel cell stack is heated or cooled through the coordination of various valves and pipes. The energy balance equation for the coolant flowing through the fuel cell stack is described as follows: (26) In this embodiment, after the coolant flows out of the fuel cell stack, it passes through the vehicle body heat exchanger and radiator in the thermal management system before entering the coolant tank. The valve opening control vector is... After passing through the heating water pump, the coolant enters the fuel cell stack. The temperature of the coolant at the fuel cell stack inlet is... for: (27) In the formula: Indicates the first The valve opening of a three-way ball valve; This indicates the temperature of the coolant passing through the vehicle body heat exchanger and radiator. In this embodiment, to stabilize the battery stack temperature and reduce heat loss, the MPC method is used to control the valve opening of the pipes containing the vehicle body heat exchanger and radiator. The core of this method is to set a target temperature so that the actual temperature of the battery stack follows the target value. Therefore, the heat demand is first set. The vector is used to define the weights of the optimization problem, where the weight is set to the heat required for battery operation to balance the importance of temperature tracking error and control quantity changes. Heat required for vehicle body operation The description is as follows: (28) The relationship between the fuel cell stack temperature, coolant flow rate, and valve opening is established using formulas (23) to (27). The weights of each component in the optimization objective are defined using formula (28). Based on these formulas, the MPC optimization problem of formula (29) is established. By solving the optimal valve opening sequence, the fuel cell stack temperature tracks the target value while reducing energy loss. (The text then abruptly shifts to a different topic: setting heat requirements.) Then, by solving the following quadratic programming problem, the optimal valve opening control sequence is obtained. .

[0057] S32: Based on the energy balance equation, construct a sequence for solving and obtaining the optimal valve opening control sequence. The quadratic programming model, i.e., the objective function of this MPC optimization problem, consists of two parts: the first part is the weighted sum of squares measuring the temperature tracking error, and the second part is the weighted sum of squares measuring the changes in the control quantity. Under the premise of satisfying the battery stack temperature, the goal is to reduce heat loss to the environment. Therefore, the following quadratic programming problem is solved, described as: (29) In the formula: This indicates the location of the pipes containing the heat exchanger and radiator in the vehicle body. k The valve opening at any given moment; Indicates the length of the prediction time domain; Indicates the temperature of the fuel cell stack; Indicates in k Time prediction k + j The temperature of the fuel cell stack at any given time; Indicates the target operating temperature of the fuel cell stack; This indicates the heat required for the dye-coated battery to operate; This indicates the heat required for the vehicle body to operate; This embodiment formulates a comprehensive cold-start strategy for hydrogen fuel cells, specifically as follows: S33: Constructing a coolant-assisted heating strategy: When the ambient temperature is detected to be below 0°C, the coolant flowing out of the coolant tank and into the hydrogen fuel cell is heated by a heating water pump until the coolant temperature reaches the first temperature threshold (15°C). At the same time, the first three-way ball valve is shut off, and the pipeline between the coolant and the vehicle heat exchanger and radiator is closed by a pre-set valve. The heating power of the heating water pump The PID control method is described as follows: (30) (31) In the formula: This represents the proportional gain of the heating power of the water pump, i.e., the response to the coolant temperature deviation. This represents the integral gain of the heating power of the water pump, reducing the steady-state error of the coolant temperature. Indicates the target temperature of the coolant; Constructing a liquid water purging strategy: During the cold start phase when the ambient temperature is below 0°C, while implementing the coolant-assisted heating strategy, to prevent the residual liquid water inside the fuel cell stack from freezing at low temperatures, hydrogen purging is performed by controlling the drain and exhaust valves in the hydrogen system to purge the liquid water in the internal flow channels with a small flow rate of hydrogen; and the purging mass flow rate of the liquid water purging strategy is... With purging time satisfy: (32) In the formula: This indicates the volume of the anode flow channel in a fuel cell; , This indicates the initial hydrogen concentration and the safe hydrogen concentration within the anode flow channel of the fuel cell; this strategy ensures that the hydrogen concentration inside the fuel cell stack is not lower than the safe value, provided that liquid water inside the stack is removed.

[0058] Simultaneously run the constructed adaptive startup current control strategy: Utilizing the self-heating effect of hydrogen fuel cells, residual water in the internal flow channels of the battery is drained during the cold start of the vehicle, preventing icing of the proton exchange membrane inside the battery. An adaptive start-up current control method is employed, firstly calculating and obtaining the ice integral of the proton exchange membrane inside the fuel cell using battery temperature and voltage detection devices and external insulation impedance detection devices. for: (33) In the formula: express The abbreviated form; This represents the defined integral function; Indicates the insulation resistance of the fuel cell; when At that time, the surface of the proton exchange membrane inside the battery is filled with liquid water, while when At this time, the proton exchange membrane is at risk of freezing, depending on the battery temperature. Ice integral Different ranges control the starting current of the fuel cell. That is, based on ice integral Combined with battery temperature Constructing the control of the start-up current of the fuel cell The control law is: (34) In the formula: This represents the initial current of the fuel cell; Indicates the temperature rise coefficient of a fuel cell; Indicates the temperature threshold; Indicates the ice integral threshold; This indicates the current starting current. By controlling the battery's starting current, the battery current can be limited when there is a risk of ice blockage in the stack flow channels, and increased when the temperature rises and there is no risk of ice formation.

[0059] S34: When the temperature of the coolant is detected to reach the second temperature threshold (20°C), the heating water pump is stopped and the hydrogen fuel cell system is put into normal operation, thereby realizing the cold start of the hydrogen fuel cell vehicle. S4: After the fuel cell starts up and operates stably, in order to solve the problem of thin oxygen at high altitudes, a lookup table control strategy is constructed by combining real-time map altitude information. This strategy takes altitude and fuel cell stack power demand as inputs and the optimal oxygen supply ratio as output. The lookup table control strategy can infer the overall pressure ratio of the air compressor based on altitude. Meanwhile, the back pressure valve opening is adjusted based on empirical values ​​to achieve operation control of the air subsystem; at the same time, an energy demand control strategy based on altitude is constructed, which is used to obtain the actual driving power demand corresponding to the vehicle being in uphill or downhill conditions. The table lookup control strategy constructed in this embodiment is as follows: In high-altitude areas, to address the problem of insufficient fuel cell output power caused by reduced oxygen intake at the fuel cell cathode in heavy-duty hydrogen fuel cell vehicles under low atmospheric pressure, this embodiment proposes a table lookup control strategy with altitude and the power demand of the hydrogen fuel cell stack as two-dimensional input variables, and the output being the oxygen supply ratio. Specifically: S41: Obtain real-time map elevation information and calculate oxygen partial pressure based on current atmospheric pressure. for: (35) In the formula: Indicates the current altitude The atmospheric pressure below; This indicates the percentage of oxygen partial pressure. S42: Based on the partial pressure of oxygen When air passes through the air compressor of the air subsystem in the fuel cell system, the oxygen pressure at the air inlet of the fuel cell increases to [a certain value]. : (36) In the formula: This indicates the overall pressure ratio at which the air compressor is operating; This indicates the increased oxygen pressure. S43: Based on the increased oxygen pressure Obtain the maximum available oxygen mass flow rate for: (37) In the formula: The proportion coefficient representing oxygen; This indicates the partial pressure of oxygen within the cathode channel of the fuel cell stack; The gas constant of oxygen; from formulas (35) to (37), it can be seen that as altitude increases, atmospheric pressure... The oxygen supply capacity of the fuel cell stack decreases as a result.

[0060] S44: To ensure the oxygen supply capacity of the fuel cell and to reduce the computational complexity of the on-board controller, based on high-altitude data, the input two-dimensional variable is defined as altitude. Power required by fuel cell stack The output is the optimal oxygen supply ratio. The lookup table method, which considers the impact of oxygen supply on battery power, defines a lookup table control strategy based on steps S41 to S43, with altitude and stack power demand as inputs and the optimal oxygen supply ratio as output. (38) In the formula: This indicates the optimal oxygen supply ratio; This represents a table lookup function; This indicates the battery power demand related to oxygen supply; according to high-altitude test data, this demand increases with altitude. Increased oxygen supply has a saturation effect on battery power improvement. Therefore, the optimal oxygen supply should be appropriately reduced as altitude increases. The table lookup rules are as follows: (1) Altitude Less than 4000m and the required power of the fuel cell stack At lower levels, the current battery is specified to be in a low-load operating state, maintaining basic stack operation, with an optimal oxygen supply ratio. Set to low value; (2) Altitude Less than 4000m and the required power of the fuel cell stack At higher levels, the current battery is operating under high load, requiring a sufficient oxygen supply to the stack to ensure high power operation. The optimal oxygen supply ratio is... Set to high value; (3) Altitude Greater than 4000m and the power required by the fuel cell stack At lower levels, the current battery is specified to be operating under low-load conditions at high altitudes, reducing the operation of the air compressor, and the optimal oxygen supply ratio is... Set to low value; (4) Altitude Greater than 4000m and the power required by the fuel cell stack At higher altitudes, the current battery is assumed to be operating under high load at high altitudes. Considering the saturation effect of oxygen supply on battery power, the optimal oxygen supply ratio is... Set to the median value.

[0061] The table lookup control strategy can use altitude and empirical values ​​to infer and obtain the overall pressure ratio of the air compressor. Meanwhile, the opening of the back pressure valve is adjusted based on empirical values ​​to achieve operation control of the air subsystem.

[0062] In this embodiment, an energy demand control strategy based on altitude is adopted. Due to the complex terrain of roads in high-altitude mountainous areas, a strategy based on altitude is formulated by combining real-time map altitude information. Power control is implemented separately when the vehicle is going uphill or downhill. Specifically: S45: Based on the physical terrain information of the current road surface obtained by the onboard navigation system, establish the vehicle power demand of the hydrogen fuel cell vehicle. The model is: (39) In the formula: Indicates the vehicle's curb weight; Represents gravitational acceleration; Indicates the coefficient of rolling friction; Indicates the drag coefficient; Indicates the windward area; Indicates the current altitude Atmospheric density below; Indicates the vehicle's speed; Indicates the slope angle; determines the vehicle's required power based on current operating conditions and status. This facilitates the subsequent development of power output strategies for vehicles on uphill and downhill slopes; S46: When the vehicle enters an uphill section, a control command is issued via a pre-set onboard controller to increase the output power of the fuel cell as follows: (40) In the formula: Indicates the uphill preloading time; The slope representing the battery's applied power; This indicates the output power ratio of the hydrogen fuel cell and the power battery; This indicates the output power required for the vehicle to go uphill; Indicates the initial time; express The maximum value; S47: When the vehicle enters a downhill section, the vehicle requires power. A negative value indicates that the vehicle has energy recovery capabilities. Through a pre-installed onboard controller, control commands are issued to recover a portion of the vehicle's gravitational potential energy by converting it into electrical energy. This means that a portion of the gravitational potential energy is converted into electrical energy and used to recharge the vehicle's battery. The energy recovery power at this time is... Limited by the maximum charging power of the power battery, it is described as follows: (41) In the formula: Indicates energy recovery efficiency; This represents the maximum charging power of the power battery. At this point, the output power of the fuel cell and the regenerative braking power together meet the actual driving needs of the vehicle, described as follows: (42) Among them, when It is a negative value. A positive value indicates energy recovery.

[0063] S5: Based on steps S1 to S4, a cooperative control strategy for heavy-duty vehicles suitable for high-altitude environments is constructed. Adaptive control of heavy-duty vehicles is achieved through this strategy. Based on the optimization of the structure and control methods of each subsystem, cooperative control strategies for startup, normal operation, and special operating conditions are formulated. Specifically, the cooperative control strategy for heavy-duty vehicles constructed in this embodiment is as follows: Start-up phase: When the ambient temperature is below 0℃, the cold start of the hydrogen fuel cell vehicle is achieved by executing the cold start integrated strategy in S3. At the same time, the temperature control strategy for the heating cable demand in S2 is executed to reduce the probability of icing in the hydrogen outlet pipeline. Specifically, when the ambient temperature is below 0°C, a cold start integrated strategy is implemented, controlling the heating water pump to operate according to formula (30) to raise the temperature of the coolant to 15°C, and the controllable PTC heater to operate according to formula (17) to heat the hydrogen temperature at the inlet of the stack; according to formula (32), a small flow of hydrogen is used to purge the liquid water inside the battery, and at the same time, according to the battery temperature in formula (34) Ice integral Controlling the starting current of the fuel cell This allows the battery to heat up on its own; at the same time, the heat tracing cable on the hydrogen outlet pipe of the fuel cell stack starts to heat up to prevent the outlet pipe from freezing; finally, when the coolant temperature reaches 20°C, the system operates normally.

[0064] Normal operation phase: Based on the current environmental conditions and vehicle status, the vehicle's required power is obtained via S45. The system obtains real-time map elevation information and uses a lookup table-based control strategy to infer the overall pressure ratio of the air compressor based on the elevation. Furthermore, the back pressure valve opening is adjusted based on empirical values ​​to achieve operation control of the air subsystem; at the same time, under the premise of meeting the stack temperature in the fuel cell, the optimal valve opening control strategy is executed to stabilize the stack temperature in the hydrogen fuel cell and reduce heat loss; in addition, the hydrogen temperature in the hydrogen subsystem is maintained by executing the constructed feedforward-feedback control strategy, and the air temperature and humidity control strategy is also executed to compensate for air heat exchange loss in the air subsystem and prevent water film humidity from decreasing. Specifically, during normal operation, the output power of the hydrogen fuel cell is made to meet the vehicle's power requirements. Based on the current environmental conditions and vehicle status, the required power of the entire vehicle is calculated using formula (39). ; Implement based on altitude Power required by fuel cell stack The input variables are two-dimensional, and the output is the optimal oxygen supply ratio. The lookup table control strategy, according to formulas (35) to (37), shows that the optimal oxygen supply ratio is... Overall pressure ratio of air compressor Relatedly, the optimal oxygen supply ratio can be determined by looking up a table. Convert to air compressor pressure ratio and back pressure valve opening command u Control commands u Adjust the overall pressure ratio of the air compressor to With respect to the back pressure valve opening; in the thermal management subsystem, under the premise of meeting the battery stack temperature, the MPC method described in formula (29) is used to control the valve opening of the three-way ball valve and proportional valve in the vehicle body heat exchanger and heat dissipation pipe. This is to reduce the loss of heat generated by the fuel cell stack.

[0065] Uphill phase in high-altitude mountainous areas: Based on S46, the output power of the fuel cell is increased, thereby realizing adaptive control operation of heavy-duty vehicles; Downhill section in high-altitude mountainous areas: The motor switches from drive mode to generator mode, based on the energy recovery power obtained from S47. Energy recovery during vehicle operation is achieved by charging the power battery through a bidirectional DC / DC unit, thereby enabling adaptive control of heavy-duty vehicles.

[0066] The beneficial effects of the system and control method described in this embodiment are as follows: For high-altitude environments, a two-stage pressurized air compressor and a controlled humidifier water film humidity control ensure air supply; the addition of a controllable PTC heater and a heated heating tape prevents icing of the hydrogen subsystem; MPC effectively manages heat in the fuel cell stack and thermal management system, stabilizing the stack temperature and enabling cold starts. Based on altitude and fuel cell stack power requirements, a lookup table rule is established to adjust the optimal oxygen supply ratio; based on the vehicle's current road terrain information, energy control strategies are developed for uphill and downhill conditions; finally, a collaborative control strategy is formulated to improve the adaptability and operating efficiency of hydrogen fuel cell heavy-duty vehicles in high-altitude environments.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments, characterized in that, This includes an air subsystem, a hydrogen subsystem, and a thermal management subsystem; The air subsystem includes a filter, an air compressor, a proportional valve, an intercooler, and a humidifier equipped with PID control, which are connected in sequence in the air inlet direction of the hydrogen fuel cell; a back pressure valve connected to the outside is provided in the air outlet direction of the hydrogen fuel cell. The air subsystem is used to provide oxygen for the chemical reaction of the hydrogen fuel cell. The hydrogen subsystem includes a hydrogen storage tank, a flow meter, a shut-off valve, a proportional valve, and a PTC heater connected sequentially in the hydrogen inlet direction of the hydrogen fuel cell. A first circulation pump is connected in the hydrogen outlet direction of the hydrogen fuel cell. The output end of the first circulation pump is connected to a second circulation pump, an exhaust valve, and a drain valve. The output end of the second circulation pump is connected to a pipeline between the heater and the hydrogen inlet of the hydrogen fuel cell. A heat tracing cable is installed on the pipeline from the hydrogen outlet of the fuel cell stack to the drain valve and the exhaust valve. The hydrogen subsystem is used to provide hydrogen for the chemical reaction of the hydrogen fuel cell and maintain the hydrogen inlet temperature and reduce the probability of icing in the hydrogen outlet pipeline through the PTC heater and the heat tracing cable. The thermal management subsystem includes a heating water pump and a coolant tank connected sequentially in the direction of the coolant inlet of the hydrogen fuel cell. The input end of the coolant tank is connected to one end of a second three-way valve. The other two ends of the second three-way valve are respectively connected to the coolant outlet of the hydrogen fuel cell and one end of a first three-way valve via pipelines. The other two ends of the first three-way valve are respectively connected to one end of the vehicle body heat exchanger and one end of the radiator. The other end of the vehicle body heat exchanger and the other end of the radiator are connected to the pipeline between the second three-way valve and the coolant tank. The thermal management subsystem is used to control the temperature of the coolant in the hydrogen fuel cell, thereby achieving temperature control of the hydrogen fuel cell stack.

2. A control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments, based on claim 1, characterized in that, Specifically, the following steps are included: S1: An air temperature and humidity control strategy based on the air subsystem, designed to compensate for heat transfer losses and prevent the decrease in water film humidity in a high-altitude environment. S2: Based on the hydrogen subsystem, a feedforward-feedback control strategy for the heater to maintain the hydrogen temperature and a temperature control strategy for the heating cable to reduce the probability of icing in the hydrogen outlet pipeline are constructed considering the high-altitude environment. S3: Based on the thermal management subsystem, an optimal valve opening control strategy is constructed to stabilize the temperature of the fuel cell stack and reduce heat loss in a high-altitude environment; at the same time, a comprehensive cold start strategy for the hydrogen fuel cell is formulated by constructing a coolant-assisted heating strategy, a liquid water purging strategy, and an adaptive start-up current control strategy. S4: After the fuel cell starts up and operates stably, a lookup table control strategy is constructed by combining real-time map altitude information. This strategy takes altitude and stack power demand as inputs and the optimal oxygen supply ratio as outputs. The lookup table control strategy can infer the overall pressure ratio of the air compressor based on altitude. Meanwhile, the back pressure valve opening is adjusted based on empirical values ​​to achieve operation control of the air subsystem; at the same time, an energy demand control strategy based on altitude is constructed, which is used to obtain the actual driving power demand corresponding to the vehicle being in uphill or downhill conditions. S5: Based on steps S1 to S4, construct a cooperative control strategy for heavy-duty vehicles suitable for high-altitude environments, and achieve adaptive control of heavy-duty vehicles through the cooperative control strategy.

3. The control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments according to claim 2, characterized in that, The air temperature and humidity control strategy described in S1 is as follows: S11: After air passes through the filter and air compressor, and is regulated by the proportional valve, it comes into contact with the heat sink in the intercooler, based on the heat exchange capacity of the heat sink. and the overall heat transfer coefficient related to altitude Obtain the required area of ​​the heat sink. for: In the formula: This represents the logarithmic mean temperature difference; This indicates the inlet and outlet temperatures of the intercooler; , This indicates the inlet and outlet temperatures of the coolant. S12: Based on PID control technology, the humidity of the air output from S11 is adjusted, and the control law for the humidifier's humidification capacity adjustment signal is constructed as follows: In the formula: This indicates the proportional gain, which is the amplification factor of the humidity deviation. This indicates that the integral gain reduces the humidity deviation under steady-state conditions. This represents the differential gain, which reduces the overshoot caused by humidity changes. Indicates the current humidity of the water film. With target humidity Deviation; This indicates the output of the humidifier, i.e., the humidification adjustment signal; Indicates time parameters; express The abbreviated form of .

4. The control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments according to claim 3, characterized in that, The feedforward-feedback control strategy constructed in S2 is specifically as follows: S21: The heat loss model for the PTC heater is established as follows: In the formula: Indicates heat loss; This represents the heat transfer coefficient between the PTC heater and the external environment; This indicates the heat dissipation area of ​​the PTC heater; Indicates ambient temperature; This indicates the core temperature of the PTC heater; S22: Obtain the hydrogen inlet temperature of the fuel cell, and construct the feedforward heating power of the PTC heater by setting the target hydrogen heating temperature and combining it with the heat loss model: In the formula: Indicates the feedforward heating power; This indicates the mass flow rate of hydrogen entering the hydrogen subsystem from the hydrogen storage tank. This indicates the specific heat capacity of hydrogen. This indicates the set target temperature for hydrogen heating; This indicates the hydrogen inlet temperature of the fuel cell; This indicates the power consumed by the PTC heater during its operation due to heat loss. Indicates the heat loss coefficient of the heater; Obtain the temperature deviation caused by the feedforward heating power. After correction, the resulting deviation in heating power is: In the formula: Indicates the deviation in heating power; The proportional gain represents the deviation in heating power; The integral gain represents the deviation heating power; S23: Based on the feedforward heating power and the deviation heating power, the expected heating power of the PTC heater is obtained as follows: In the formula: Indicates the desired heating power; These represent the minimum and maximum values ​​of the heating power within the corresponding safety constraint range, respectively. express The abbreviated form of .

5. The control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments according to claim 4, characterized in that, The specific temperature control strategy for the electric heating cable described in S2 is as follows: S24: Obtain the heating power of the electric heating tape based on its resistance. for: In the formula: This indicates the voltage of the electric heating tape. This indicates that the electric heating cable has a temperature of [temperature value missing]. The resistance below; This indicates the temperature coefficient of the electric heating tape; Indicates reference temperature; S25: Based on the heating power of the electric heat tracing tape The heat balance model for the hydrogen outlet pipeline is as follows: In the formula: This indicates the heat dissipation capacity of the hydrogen outlet pipeline; This represents the heat transfer coefficient of the hydrogen outlet pipeline; Indicates the cross-sectional radius of the hydrogen outlet pipeline; S26: The exponent term is simplified using a first-order Taylor expansion. Substitute this into the heat balance model to solve for the required temperature of the electric heating cable: In the formula: This indicates that the electric heating cable is at the reference temperature. The resistance below; Indicates ambient temperature.

6. The control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments according to claim 5, characterized in that, The optimal valve opening control strategy in S3 is as follows: S31: Establish information about the heat generated by the fuel cell stack Heat carried away by the coolant and heat loss The energy balance equation between them is: In the formula: Indicates the heat capacity of the fuel cell stack; Indicates the temperature of the fuel cell stack; Indicates the mass of coolant; Indicates the heat capacity of the coolant; , These represent the temperatures of the coolant at the fuel cell outlet and inlet, respectively. Indicates the current in the fuel cell stack; This represents the thermodynamic voltage of the fuel cell stack; Indicates the stack voltage; Indicates the first The valve opening of a three-way ball valve; This indicates the temperature of the coolant after passing through the vehicle body heat exchanger and radiator. S32: Based on the energy balance equation, construct a sequence for solving and obtaining the optimal valve opening control sequence. The quadratic programming model is as follows: In the formula: This indicates the location of the pipes containing the heat exchanger and radiator in the vehicle body. k The valve opening at any given moment; Indicates the length of the prediction time domain; Indicates the temperature of the fuel cell stack; Indicates in k Time prediction k + j The temperature of the fuel cell stack at any given time; Indicates the target operating temperature of the fuel cell stack; This indicates the heat required for the dye-coated battery to operate; This indicates the heat required for the vehicle body to operate.

7. The control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments according to claim 6, characterized in that, The specific cold start strategy for hydrogen fuel cells formulated in S3 is as follows: S33: Construct a coolant-assisted heating strategy: When the current ambient temperature is detected to be below 0°C, the coolant flowing out of the coolant tank and into the hydrogen fuel cell is heated by a heating water pump. When the temperature of the coolant reaches the first temperature threshold, the first three-way ball valve is shut off, and the pipeline between the coolant and the vehicle heat exchanger and radiator is closed by a pre-set valve. The heating power of the heating water pump for: In the formula: This represents the proportional gain of the heating power of the water pump. The integral gain represents the heating power of the water pump. Indicates the target temperature of the coolant; A liquid water purging strategy is constructed: during the cold start phase when the ambient temperature is below 0°C, while implementing the coolant-assisted heating strategy, hydrogen purging is performed by controlling the drain and exhaust valves of the hydrogen system to remove liquid water from its internal flow channels; and the purging mass flow rate of the liquid water purging strategy is... With purging time satisfy: In the formula: Indicates the volume of the anode flow channel in a fuel cell; , This indicates the initial hydrogen concentration and the safe hydrogen concentration within the anode flow channel of the fuel cell; Simultaneously, the constructed adaptive start-up current control strategy is executed: the ice integral of proton exchange membrane icing inside the fuel cell is calculated and obtained. for: In the formula: express The abbreviated form; This represents the defined integral function; Indicates the insulation resistance of the fuel cell; And based on ice integral Combined with battery temperature Constructing the control of the start-up current of the fuel cell The control law is: In the formula: This represents the initial current of the fuel cell; Indicates the temperature rise coefficient of a fuel cell; Indicates the temperature threshold; Indicates the ice integral threshold; Indicates the current starting current; S34: When the temperature of the coolant is detected to reach the second temperature threshold, the heating water pump is stopped and the hydrogen fuel cell system is put into normal operation, thereby realizing the cold start of the hydrogen fuel cell vehicle.

8. The control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments according to claim 7, characterized in that, The table lookup control strategy constructed in S4 is specifically as follows: S41: Obtain real-time map elevation information and calculate oxygen partial pressure based on current atmospheric pressure. for: In the formula: Indicates the current altitude The atmospheric pressure below; This indicates the percentage of oxygen partial pressure. S42: Based on the partial pressure of oxygen When air passes through the air compressor of the air subsystem in the fuel cell system, the oxygen pressure at the air inlet of the fuel cell increases to [a certain value]. : In the formula: This indicates the overall pressure ratio at which the air compressor operates; This indicates the increased oxygen pressure. S43: Based on the increased oxygen pressure Obtain the maximum available oxygen mass flow rate for: In the formula: The proportion coefficient representing oxygen; This indicates the partial pressure of oxygen within the cathode channel of the fuel cell stack; The gas constant representing oxygen; S44: Considering the impact of oxygen supply on battery power, based on steps S41 to S43, a lookup table control strategy is defined, with altitude and stack power demand as inputs and the optimal oxygen supply ratio as output: In the formula: This indicates the optimal oxygen supply ratio; This represents a table lookup function; This indicates the battery power demand related to oxygen supply. The table lookup control strategy can use altitude as a basis to infer and obtain the overall pressure ratio of the air compressor. Meanwhile, the opening of the back pressure valve is adjusted based on empirical values ​​to achieve operation control of the air subsystem.

9. The control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments according to claim 8, characterized in that, The energy demand control strategy based on altitude in S4 is as follows: S45: Based on the physical terrain information of the current road surface obtained by the onboard navigation system, establish the vehicle power demand of the hydrogen fuel cell vehicle. The model is: In the formula: Indicates the vehicle's curb weight; Represents gravitational acceleration; Indicates the coefficient of rolling friction; Indicates the drag coefficient; Indicates the windward area; Indicates the current altitude Atmospheric density below; Indicates the vehicle's speed; Indicates the angle of inclination; S46: When the vehicle enters an uphill section, a control command is issued via a pre-set onboard controller to increase the output power of the fuel cell as follows: In the formula: Indicates the uphill preloading time; The slope representing the battery's applied power; This indicates the output power ratio of the hydrogen fuel cell and the power battery; This indicates the output power required for the vehicle to go uphill; Indicates the initial time; express The maximum value; S47: When the vehicle enters a downhill slope, a control command is issued through a pre-set onboard controller to recover a portion of the vehicle's gravitational potential energy by converting it into electrical energy. This energy recovery process converts a portion of the gravitational potential energy into electrical energy and recharges the vehicle's battery. The energy recovery power is [not specified in the original text]. for: In the formula: Indicates energy recovery efficiency; This indicates the maximum charging power of the power battery.

10. The control method for a heavy-duty vehicle hydrogen fuel cell system suitable for high-altitude environments according to claim 9, characterized in that, The heavy-duty vehicle cooperative control strategy for high-altitude environments constructed in S5 is as follows: S51: Confirm the current operating phase of the heavy-duty vehicle; The operation phases include the startup phase, normal operation phase, uphill phase, and downhill phase; If the running phase is confirmed to be the startup phase, then execute S52; If the operation phase is confirmed to be the normal operation phase, then execute S53; If the operation phase is confirmed to be an uphill phase, then execute S54; If the operation phase is confirmed to be a downhill phase, then execute S55; S52: When the ambient temperature is below 0℃, the cold start of the hydrogen fuel cell vehicle is achieved by executing the cold start integrated strategy in S3. At the same time, the temperature control strategy for the heating cable demand in S2 is executed to reduce the probability of icing in the hydrogen outlet pipeline. S53: Based on the current environmental conditions and vehicle status, obtain the vehicle's required power through S45. The system obtains real-time map elevation information and uses a lookup table-based control strategy to infer the overall pressure ratio of the air compressor based on the elevation. Furthermore, the back pressure valve opening is adjusted based on empirical values ​​to achieve operational control of the air subsystem; simultaneously, while ensuring the stack temperature in the fuel cell is met, the optimal valve opening control strategy is implemented to stabilize the stack temperature in the hydrogen fuel cell and reduce heat loss. In addition, the hydrogen temperature in the hydrogen subsystem is maintained by implementing the constructed feedforward-feedback control strategy, and the air temperature and humidity control strategy is also implemented to compensate for the air heat exchange loss in the air subsystem and prevent the water film humidity from decreasing. S54: Based on S46, obtain the increased output power of the fuel cell, thereby achieving adaptive control operation of heavy-duty vehicles; S55: Energy recovery power based on S47 Energy is recovered during vehicle operation to achieve adaptive control of heavy-duty vehicles.

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