Hydrogen fuel cell unmanned aerial vehicle control method and unmanned aerial vehicle system

Abstract

The invention discloses a hydrogen fuel cell unmanned aerial vehicle control method and an unmanned aerial vehicle system, particularly relates to a hydrogen supply and energy management scheme for a large cargo-carrying unmanned aerial vehicle, and belongs to the technical field of aircraft energy management. The system adopts the combination of a main fuel cell and a plurality of secondary fuel cells, and in the invention, in order to improve the working efficiency and the endurance of the fuel cells, an intelligent control method is designed to adjust hydrogen supply in real time, ensure the most effective utilization of hydrogen in different flight stages and environment conditions, and improve the endurance. The design not only improves the stability and reliability of the unmanned aerial vehicle, but also improves the coping ability of the unmanned aerial vehicle in a complex environment. The fuel cell unmanned aerial vehicle system has high energy efficiency, long cruising ability and strong emergency processing ability, and is suitable for various heavy cargo transportation, agricultural spraying and other unmanned aerial vehicle application scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft energy management. More specifically, the present invention relates to an efficient hydrogen fuel cell intake and safety management system for large long-endurance unmanned aerial vehicles (UAVs). Background Art

[0002] With the continuous progress of technology, the application of UAVs is becoming increasingly widespread. Due to the low cost and high efficiency of UAV technology, it also shows great potential in industrial transportation and the agricultural field. Hydrogen fuel cells, which use hydrogen as the core power source and have the characteristics of zero emissions and long endurance, are also widely used in large long-endurance UAVs. However, existing UAV fuel cell systems usually have some deficiencies, especially in terms of stability and safety.

[0003] In terms of stability, the intake port designs of many current UAV fuel cell systems are fixed, lacking adaptability to environmental conditions and unable to effectively adjust the state of the air flow when it enters the fuel cell. In terms of safety, many current UAV fuel cell systems lack attention to the health of the fuel cell and countermeasures for when the fuel cell fails.

[0004] To ensure the safe and stable power supply of the hydrogen fuel cell on the UAV in various situations, and to ensure that the UAV can land safely regardless of extreme environments or fuel cell failures, it is necessary to redesign the intake system of the hydrogen fuel cell and add a risk management module dedicated to the UAV.

[0005] In view of this, the present invention proposes a control method and a UAV system for a large long-endurance hydrogen fuel cell UAV to solve the above problems. Summary of the Invention

[0006] To overcome the above-mentioned defects of the prior art and to achieve the above object, the present invention provides the following technical solutions: A control method and a UAV system for a hydrogen fuel cell UAV, which are applied to the fuel cell management installed on the UAV, and include:

[0007] Main fuel cell, multiple secondary fuel cells, hydrogen storage cylinder, emergency oxygen cylinder, lithium battery, air inlet; The air inlet is installed under the drone, can rotate freely, is equipped with a device for controlling the cross-section at the front end, is equipped with a dust filter in the middle, and multiple intake fans and gas flow sensors are built into the rear end; The air inlet is connected to an air chamber behind it. The cross-sectional area of the air chamber is the same as the maximum cross-sectional area of the air inlet. A particulate pollutant sensor, a temperature and humidity maintenance module, and a supercharger are installed in the air chamber. Pressure sensors are installed at both the intake and outlet of the supercharger; The air chamber is connected to a compartment where the main fuel cell and the auxiliary fuel cell are installed. The two types of batteries are located in separate compartments. The hydrogen storage cylinder and the emergency oxygen cylinder are independent and controllable for the gas supply of these two types of fuel cells.

[0008] Further, for drones with different powers, main fuel cells with different powers and different numbers of secondary fuel cells should be selected; The main fuel cell provides power for high-power demand parts such as drive motors, usually operating near the optimal efficiency point, and main fuel cells with different powers are selected according to the specific power of different drones; The secondary fuel cell group is used to provide power for low-power demand parts such as the control system and sensors. It adopts a redundant design and consists of multiple small-power fuel cells of about 300W. Its quantity is determined according to the total power of the drone. It should ensure that it can independently supply the drone's operation when operating at the maximum power. Usually, hydrogen is supplied according to the power demand of the low-voltage system and is in a low-power operation state;

[0009] The lithium battery is used to make up for the missing power when the power of the drive motor fluctuates; The emergency oxygen cylinder should store at least enough oxygen to supply the drone's flight for half an hour and is usually in a closed state;

[0010] The system will monitor the power demand of the drive motor in real time. When the power demand of the drive motor fluctuates violently, the system controls the lithium battery to make up for the missing power of the main fuel cell; When the power fluctuation tends to be stable and lasts for more than ten seconds, the system will increase the hydrogen supply of the secondary fuel cell, raise its power, and charge the lithium battery;

[0011] Further, the oxygen content stored in the emergency oxygen cylinder is determined by the following formula:

[0012]

[0013] Among them, is the oxygen stored in the emergency oxygen cylinder at least, is the oxygen excess coefficient, is the number of secondary fuel cells, is the number of single fuel cell pieces, is the Faraday constant, is the molar mass of oxygen, The power required for the drone to operate for half an hour;

[0014] For both the main fuel cell and the secondary fuel cell, a calculation should be carried out once, and the larger calculation result is selected as the oxygen capacity of the emergency oxygen cylinder;

[0015] The hydrogen supply of the hydrogen storage cylinder to the main fuel cell and the secondary fuel cell is determined by the following formula:

[0016]

[0017] Among them, is the hydrogen released by the hydrogen storage cylinder per second, is the number of fuel cells, is the number of single fuel cell plates, is the Faraday constant, is the molar mass of oxygen, is determined by the control system. For the main fuel cell, it is the power consumed by high-power demand parts such as the drive motor. For the secondary fuel cell, it is the power consumed by low-power demand parts such as the control system and sensors plus the power consumed by the intermittent charging of the lithium battery. In case of an emergency, it becomes the total power consumption of the drone;

[0018] Furthermore, the air inlet is controlled by the following method:

[0019] S1, Obtain the current environmental wind direction and wind speed as well as the particulate pollution index in the cylindrical air chamber;

[0020] S2, Adjust the air inlet to keep it facing against the wind and adjust it to the maximum opening;

[0021] S3, When the drone just starts or the environmental wind speed < the optimal gas flow rate outside and lasts for more than 10 s, start the fan and continuously adjust the fan speed according to the real-time monitored environmental wind speed and the inlet air flow rate to maintain the flow rate entering the fuel cell stable near the optimal gas flow rate at the cathode of the fuel cell;

[0022] S4, When the environmental wind speed > the optimal gas flow rate outside and lasts for more than 10 s, turn off the fan and appropriately reduce the opening of the air inlet to keep the flow rate stable near the optimal gas flow rate at the cathode of the fuel cell;

[0023] And, the temperature and humidity maintenance module in the air chamber will keep the gas temperature and humidity stable within the range most suitable for the fuel cell to work, and the supercharger will keep the air pressure stable at the standard atmospheric pressure.

[0024] Furthermore, there is a specific optimal air flow rate at the cathode of the fuel cell. Due to the effect of the supercharger and the change of the external air pressure with altitude, after calculation, the relationship between the external optimal air flow rate, the external air pressure and the optimal air flow rate at the cathode of the fuel cell is as follows:

[0025]

[0026] Among them, is the optimal gas flow rate outside, is the optimal air flow rate at the cathode of the fuel cell, is the external air pressure, is the standard atmospheric pressure, is the gas constant, is the absolute temperature of the gas, is the molar mass of the gas, and h is the height of the drone;

[0027] When the external wind speed is less than the optimal gas flow rate outside, the fan speed is determined by the following formula:

[0028]

[0029] Among them, is the fan speed, is the optimal gas flow rate outside, is the external wind speed, is the thrust coefficient of the fan, which is determined by the fan;

[0030] When the external wind speed is greater than the optimal gas flow rate outside, the change in the cross-sectional area of the air inlet is determined by the following formula:

[0031]

[0032] Among them, is the adjusted cross-sectional area of the air inlet, is the maximum cross-sectional area of the original air inlet, is the external wind speed, is the optimal gas flow rate outside.

[0033] Furthermore, due to the limitations of the functions of the temperature and humidity maintenance module and the dust-proof net, the main fuel cell and the secondary fuel cell operate in a harsh environment. To avoid this situation, the system will run a risk management module based on logical judgment, and comprehensively judge the gas harshness index in the cylindrical gas chamber by weighted analysis according to the characteristics of the stack combined with the detection data of temperature, humidity and particle pollution;

[0034] The harshness index ( ) is the weighted sum based on temperature, humidity and particle pollution concentration, and the calculation formula is as follows:

[0035]

[0036] In the formula, temperature ( ), humidity ( ), and particle pollution concentration ( is provided by the data acquisition module; the temperature weight ( ), the humidity weight ( ), and the particulate contamination weight ( ) are all determined by the characteristics of the fuel cell stack used and are all 1 / 3; is the normalization function of temperature, representing the influence of temperature on the severity level, with a value range of [0, 1]; is the normalization function of humidity, representing the influence of humidity on the severity level, with a value range of [0, 1]; is the normalization function of particulate contamination, representing the influence of particulate contamination on the severity level, with a value range of [0, 1];

[0037] The temperature normalization function :

[0038]

[0039] wherein, and are respectively the lower limit and the upper limit of temperature, is the optimal temperature, all determined by the stack characteristics;

[0040] The temperature normalization function :

[0041]

[0042] wherein, is the upper limit of humidity, determined by the stack characteristics;

[0043] The particulate contamination normalization function :

[0044]

[0045] wherein, is the upper limit of particulate contamination, determined by the stack characteristics;

[0046] Generally, when the severity index ( ) exceeds 0.8, it is determined that the current working environment will affect the working life of the UAV.

[0047] Furthermore, the risk management module is used to deal with the following three risks:

[0048] First, when the severity index ( When it exceeds 0.8 and exceeds 60 seconds, close the air inlet, give priority to power supply to the flight control module and positioning module of the drone, reduce or stop power supply to non-critical components, start the built-in emergency oxygen cylinder, provide pure oxygen to the main fuel cell, analyze according to the current positioning and average power consumption. If the set goal can be completed within half an hour, continue to execute the task. If not, control the drone to make an emergency landing and send a distress signal;

[0049] II. When the main fuel cell fails, automatically close the air inlet, give priority to power supply to the flight control module and positioning module of the drone, reduce or stop power supply to non-critical components, start the built-in emergency oxygen cylinder, provide pure oxygen to the secondary fuel cell, and supply hydrogen according to the result obtained from the formula Cooperate with the lithium battery, analyze according to the current positioning and average power consumption. If the set goal can be completed within half an hour, continue to execute the task. If not, control the drone to make an emergency landing and send a distress signal;

[0050] III. When part of the secondary fuel cell group fails, the system will try to increase its hydrogen supply to complete the original task. If the power cannot meet the demand even when the hydrogen is increased to the maximum, increase the hydrogen supply of the main fuel cell to make up for the missing power. The increased hydrogen supply is calculated according to the formula Calculated.

[0051] Compared with the prior art, the advantages of the present invention are as follows:

[0052] An innovative adjustable air inlet that can dynamically adjust the opening degree and direction according to real-time environmental conditions, combined with an intelligent fan and numerous gas state adjustment devices in the air chamber, constitutes a comprehensive air intake management system, thus significantly improving the adaptability and stability of the drone in complex climates, ensuring that the fuel cell always operates at the best efficiency, increasing the utilization rate of hydrogen, and enhancing the endurance; in addition, the system incorporates a risk management mechanism, quickly responds to the impact of sudden changes in the environment on the fuel cell by real-time monitoring of environmental parameters, thereby enhancing the safety and reliability of the drone. Combining the multiple power source configurations of the main fuel cell and the secondary fuel cell greatly improves the safety redundancy, ensuring that the drone can still land safely under various dangerous conditions. Description of the Drawings

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0054] Figure 1 It is a structural schematic diagram;

[0055] Figure 2 is Figure 1 a top view schematic diagram of;

[0056] Figure 3 is Figure 1 a bottom view schematic diagram of;

[0057] Reference numerals:

[0058] 1. Hydrogen storage cylinder; 2. Emergency oxygen cylinder; 3. Main fuel cell; 4. Secondary fuel cell; 5. Air inlet. Detailed implementation manners

[0059] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0060] Please refer to Figure 1 as shown, a control method and an unmanned aerial vehicle system for a large long-endurance hydrogen fuel cell unmanned aerial vehicle according to this embodiment are applied to a battery management system and include:

[0061] A main fuel cell 3, a plurality of secondary fuel cells 4, a hydrogen storage cylinder 1, an emergency oxygen cylinder 2, a lithium battery, and an air inlet 5; the air inlet 5 is installed below the unmanned aerial vehicle, can rotate freely, is provided with a device for controlling the cross-section at the front end, is provided with a dust-proof net in the middle, and is internally provided with a plurality of intake fans and a gas flow rate sensor at the rear end; the air inlet 5 is connected to an air chamber at the rear, the cross-sectional area of the air chamber is the same as the maximum cross-sectional area of the air inlet 5, a particulate pollutant sensor, a temperature and humidity maintenance module, and a supercharger are installed in the air chamber, and air pressure sensors are installed at the inlet and outlet of the supercharger; the air chamber is connected to a compartment where the main fuel cell 3 and the auxiliary fuel cell are installed at the rear, the two types of fuel cells are located in mutually isolated compartments, and the gas supply of the hydrogen storage cylinder 1 and the emergency oxygen cylinder 2 to these two types of fuel cells is independent and controllable.

[0062] The air inlet 5 is controlled by the following method:

[0063] S1. Obtain the current environmental wind direction and wind speed and the particulate pollution index in the cylindrical air chamber;

[0064] S2. Adjust the air inlet 5 to keep it facing against the wind and adjust it to the maximum opening;

[0065] S3. When the drone has just started or the ambient wind speed < the optimal external gas flow rate and lasts for more than 10 s, start the fan and continuously adjust the rotational speed of the fan according to the real-time monitored ambient wind speed and the intake air flow rate to maintain the flow rate entering the fuel cell stable near the optimal gas flow rate at the cathode of the fuel cell;

[0066] S4. When the ambient wind speed > the optimal external gas flow rate and lasts for more than 10 s, turn off the fan and appropriately reduce the opening degree of the air inlet 5 to make the flow rate stable near the optimal gas flow rate at the cathode of the fuel cell;

[0067] Moreover, the temperature and humidity maintenance module in the air chamber will stabilize the gas temperature and humidity within the range most suitable for the operation of the fuel cell, and the supercharger will stabilize the air pressure at the standard atmospheric pressure.

[0068] There is a specific optimal air flow rate at the cathode of the fuel cell. Due to the effect of the supercharger and the change of the external air pressure with altitude, after calculation, the relationship between the optimal external air flow rate, the external air pressure, and the optimal air flow rate at the cathode of the fuel cell is as follows:

[0069]

[0070] Among them, is the optimal external gas flow rate, is the optimal air flow rate at the cathode of the fuel cell, is the external air pressure, is the standard atmospheric pressure, is the gas constant, is the absolute temperature of the gas, is the molar mass of the gas, and h is the altitude of the drone;

[0071] When the external wind speed is less than the optimal external gas flow rate, the rotational speed of the fan is determined by the following formula:

[0072]

[0073] Among them, is the rotational speed of the fan, is the optimal external gas flow rate, is the external wind speed, is the thrust coefficient of the fan, which is determined by the fan;

[0074] When the external wind speed is greater than the optimal external gas flow rate, the change in the cross-sectional area of the air inlet 5 is determined by the following formula:

[0075]

[0076] Among them, is the adjusted cross-sectional area of the air inlet 5, is the maximum cross-sectional area of the original air inlet 5, is the external wind speed, is the optimal external gas flow rate.

[0077] The above-mentioned mechanisms together constitute the intake air management module, whose advantages lie in its intelligence, dynamic adjustment, and high efficiency, enabling the drone to maintain the best operating state under various environmental conditions, significantly improving the working efficiency of the fuel cell, and extending the endurance time of the drone.

[0078] For drones with different powers, the main fuel cell 3 with different powers and different numbers of secondary fuel cells 4 should be selected; the main fuel cell 3 provides power for high-power demand parts such as the drive motor, usually operating near the best efficiency point, and different powers of the main fuel cell 3 are selected according to the specific power of different drones; the secondary fuel cell 4 group is used to provide power for low-power demand parts such as the control system and sensors, adopting a redundant design, consisting of multiple small-power fuel cells of about 300W, and its number is determined according to the total power of the drone, and it should ensure that it can independently supply the operation of the drone during maximum power operation, and usually supply hydrogen according to the power demand of the low-voltage system, and the hydrogen supply amount is determined according to the formula to be in a low-power operation state;

[0079] The lithium battery is used to make up for the missing power when the power of the drive motor fluctuates; the emergency oxygen cylinder 2 should store at least enough oxygen for the drone to fly for half an hour, and is usually in a closed state;

[0080] The system will monitor the power demand of the drive motor in real time. When the power demand of the drive motor fluctuates violently, the system controls the lithium battery to make up for the missing power of the main fuel cell 3; when the power fluctuation tends to be stable and lasts for more than ten seconds, the system will increase the hydrogen supply of the secondary fuel cell 4, raise its power, and charge the lithium battery. The specific increased hydrogen supply amount is determined according to the formula to be determined;

[0081] This design of the main and secondary fuel cells can significantly improve the utilization rate of hydrogen and the safety factor of the system;

[0082] The oxygen content stored in the emergency oxygen cylinder 2 is determined by the following formula:

[0083]

[0084] Among them, is the oxygen that the emergency oxygen cylinder 2 stores at least, is the oxygen excess coefficient, is the number of secondary fuel cells 4, is the number of single fuel cells, is the Faraday constant, is the molar mass of oxygen, is the power required for the drone to operate for half an hour;

[0085] For both the main fuel cell 3 and the secondary fuel cell 4, a calculation should be performed once, and the larger calculation result should be selected as the oxygen capacity of the emergency oxygen cylinder 2;

[0086] The hydrogen supply of the hydrogen storage cylinder 1 to the main fuel cell 3 and the secondary fuel cell 4 is determined by the following formula:

[0087]

[0088] where, is the hydrogen released per second by the hydrogen storage cylinder 1, is the number of fuel cells, is the number of single fuel cell plates, is the Faraday constant, is the molar mass of oxygen, is determined by the control system. For the main fuel cell 3, it is the power consumed by high-power demand parts such as the drive motor. For the secondary fuel cell 4, it is the power consumed by low-power demand parts of the control system and sensors plus the power consumed by the intermittent charging of the lithium battery. In case of an emergency, it becomes the total power consumption of the drone;

[0089] Due to the limitations of the functions of the temperature and humidity maintenance module and the dust filter, the main fuel cell 3 and the secondary fuel cell 4 still operate in a harsh environment. To avoid this situation, the system will run a risk management module based on logical judgment. According to the characteristics of the fuel cell stack and combined with the detection data of temperature, humidity, and particle pollution, a weighted analysis is performed to comprehensively judge the gas harshness index in the cylindrical gas chamber;

[0090] The harshness index ( ) is a weighted sum based on temperature, humidity, and particle pollution concentration, and the calculation formula is as follows:

[0091]

[0092] In the formula, temperature ( ), humidity ( ), and particle pollution concentration ( ) are provided by the data acquisition module; the temperature weight ( ), humidity weight ( ), and particle pollution weight ( ) are determined by the characteristics of the fuel cell stack used and are all 1 / 3; is the normalization function of temperature, indicating the influence of temperature on harshness, with a value range of [0, 1]; It is a normalized function of humidity, representing the influence of humidity on the severity, with a value range of [0, 1]; It is a normalized function of particulate pollution, representing the influence of particulate pollution on the severity, with a value range of [0, 1];

[0093] The temperature normalization function :

[0094]

[0095] where and are the lower limit and upper limit of temperature respectively, is the optimal temperature, all determined by the characteristics of the fuel cell stack;

[0096] The temperature normalization function :

[0097]

[0098] where is the upper limit of humidity, determined by the characteristics of the fuel cell stack;

[0099] The particulate pollution normalization function :

[0100]

[0101] where is the upper limit of particulate pollution, determined by the characteristics of the fuel cell stack;

[0102] Generally, when the severity index ( ) exceeds 0.8, it is determined that the current working environment will affect the working life of the drone.

[0103] The risk management module is used to deal with the following three risks:

[0104] First, when the severity index ( ) exceeds 0.8 and exceeds 60 seconds, close the air inlet 5, give priority to supplying power to the flight control module and positioning module of the drone, reduce or stop the power supply to non-critical components, start the built-in emergency oxygen cylinder 2 to provide pure oxygen for the main fuel cell 3, analyze according to the current positioning and average power consumption. If the set goal can be completed within half an hour, continue to execute the task. If not, control the drone to make an emergency landing and send a distress signal;

[0105] II. When the main fuel cell 3 fails, the air inlet 5 is automatically closed, and power is preferentially supplied to the flight control module and positioning module of the UAV, reducing or stopping the power supply to non-critical components. The built-in emergency oxygen cylinder 2 is activated to provide pure oxygen for the secondary fuel cell 4, and hydrogen is supplied according to the result obtained from the formula Cooperating with the lithium battery, analyze based on the current positioning and average power consumption. If the set goal can be achieved within half an hour, the task is continued; otherwise, the UAV is controlled to land emergently and a distress signal is sent.

[0106] III. When some of the secondary fuel cell 4 groups fail, the system will attempt to increase its hydrogen supply to complete the original task. If the power cannot meet the demand even when the hydrogen is increased to the maximum, the hydrogen supply of the main fuel cell 3 is increased to make up for the missing power. The increased hydrogen supply is calculated according to the formula Calculated.

[0107] The risk management module can effectively identify, evaluate, and respond to potential risks, thus ensuring the safety and stability of the system. It also integrates a variety of emergency response strategies to ensure the safe landing of the UAV in a dangerous environment. The flexibility of this module enables it to adapt to different application scenarios. Whether in cargo transportation, agricultural spraying, or rescue missions, it can effectively manage specific operating conditions and potential risks.

[0108] It should be noted that in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0109] The above are only the specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A hydrogen fuel cell drone system, comprising a main fuel cell (3), a plurality of secondary fuel cells (4), a hydrogen storage bottle (1), an emergency oxygen bottle (2), a lithium battery, and an air inlet (5); characterized in that: The air inlet (5) is installed below the drone and can rotate freely. A device for controlling the cross section is installed at the front end of the air inlet (5). A dust screen is installed in the middle of the air inlet (5). A plurality of air inlet fans and a gas flow rate sensor are built in the rear end of the air inlet (5). The air inlet (5) is connected to an air chamber at the rear end. The cross-sectional area of ​​the air chamber is consistent with the maximum cross-sectional area of ​​the air inlet (5). A particle pollutant sensor, a temperature and humidity maintenance module and a supercharger are installed in the air chamber. Air pressure sensors are installed at the air inlet and air outlet of the supercharger. The air chamber is connected to a compartment at the rear end where the main fuel cell (3) and the auxiliary fuel cell are installed. The main fuel cell (3) and the auxiliary fuel cell are located in compartments isolated from each other. The hydrogen storage bottle (1) and the emergency oxygen bottle (2) are independent and controllable in supplying gas to the main fuel cell (3) and the auxiliary fuel cell.

2. A hydrogen fuel cell drone system according to claim 1, characterized in that: For drones of different powers, main fuel cells (3) of different powers and different numbers of secondary fuel cells (4) should be selected; the main fuel cell (3) provides power for high-power demand parts such as drive motors, and usually operates near the optimal efficiency point. Main fuel cells (3) of different powers are selected according to the specific power of different drones; the secondary fuel cell (4) group is used to provide power for low-power demand parts of control systems and sensors, adopts a redundant design, and is composed of multiple low-power fuel cells of about 300W. The number of secondary fuel cells is determined according to the total power of the drone, and should ensure that the drone can be independently supplied when operating at maximum power. Normally, hydrogen is supplied according to the power demand of the low-voltage system and it is in a low-power operation state; The lithium battery is used to make up for the missing power when the power of the driving motor fluctuates; the emergency oxygen cylinder (2) should store at least enough oxygen to supply the drone for half an hour of flight and is usually in a closed state; The system will monitor the power demand of the drive motor in real time. When the power demand of the drive motor fluctuates violently, the system will control the lithium battery to supplement the power missing from the main fuel cell (3). When the power fluctuation tends to be stable and lasts for more than ten seconds, the system will increase the hydrogen supply to the secondary fuel cell (4), increase its power, and charge the lithium battery.

3. A hydrogen fuel cell drone system according to claim 2, characterized in that: The oxygen content stored in the emergency oxygen cylinder (2) is determined by the following formula: ； in, The minimum amount of oxygen stored in the emergency oxygen cylinder (2) is: is the oxygen excess coefficient, is the number of secondary fuel cells (4), is the number of fuel cell chips, is the Faraday constant, is the molar mass of oxygen, The power required to operate the drone for half an hour; A calculation should be performed once for both the main fuel cell (3) and the secondary fuel cell (4), and the larger calculation result should be selected as the oxygen capacity of the emergency oxygen cylinder (2); The amount of hydrogen supplied by the hydrogen storage bottle (1) to the main fuel cell (3) and the secondary fuel cell (4) is determined by the following formula: ； in, is the amount of hydrogen released per second from the hydrogen storage bottle (1), is the number of fuel cells, is the number of fuel cell chips, is the Faraday constant, is the molar mass of oxygen, The power consumed by the main fuel cell (3) for the high power demand part such as the drive motor, and the power consumed by the secondary fuel cell (4) for the low power demand part of the control system and sensor plus the power consumed by the intermittent charging of the lithium battery are determined by the control system, and are converted into the overall power consumption of the drone in an emergency.

4. A hydrogen fuel cell drone control method, applied to the hydrogen fuel cell drone system described in any one of claims 1 to 3, characterized in that: The air inlet (5) is controlled by the following method: S1, obtaining the current ambient wind direction and wind speed and the particle pollution index in the cylindrical air chamber; S2, adjusting the air inlet (5) to keep it facing against the wind and to the maximum opening; S3, when the UAV is just started or the ambient wind speed is less than the optimal gas flow rate outside and lasts for more than 10 seconds, the fan is started and the fan speed is continuously adjusted according to the real-time monitored ambient wind speed and intake air flow rate to maintain the flow rate entering the fuel cell stable near the optimal gas flow rate of the fuel cell cathode; S4, when the ambient wind speed is greater than the external optimal gas flow rate and lasts for more than 10 seconds, the fan is turned off and the opening of the air inlet (5) is appropriately reduced to stabilize the flow rate near the optimal gas flow rate of the fuel cell cathode; In addition, the temperature and humidity maintenance module in the gas chamber will stabilize the gas temperature and humidity within the range most suitable for the operation of the fuel cell, and the supercharger will stabilize the gas pressure at the standard atmospheric pressure.

5. A hydrogen fuel cell drone control method according to claim 4, characterized in that: The fuel cell cathode has a specific optimal airflow velocity. Due to the effect of the supercharger and the change of the external air pressure with the height, the relationship between the external optimal airflow velocity, the external air pressure and the optimal airflow velocity of the fuel cell cathode is calculated as follows: ； in, is the optimal gas flow rate outside, is the optimal gas flow rate at the cathode of the fuel cell, is the outside air pressure, is the standard atmospheric pressure, is the gas constant, is the absolute temperature of the gas, is the molar mass of the gas, h is the altitude of the drone; When the outside wind speed is less than the outside optimal gas flow rate, the fan speed is determined by the following formula: ； in, is the fan speed, is the optimal gas flow rate outside, is the outside wind speed, is the thrust coefficient of the fan, which is determined by the fan; When the external wind speed is greater than the external optimal gas flow rate, the change in the cross-sectional area of ​​the air inlet (5) is determined by the following formula: ； in, is the cross-sectional area of ​​the air inlet (5) after adjustment, is the maximum cross-sectional area of ​​the original air inlet (5), is the outside wind speed, is the optimal gas flow rate outside.

6. A hydrogen fuel cell drone control method according to claim 5, characterized in that: Due to the limitation of the functions of the temperature and humidity maintenance module and the dustproof net, the main fuel cell (3) and the secondary fuel cell (4) may still operate in a harsh environment. In order to avoid this situation, the system will run a risk management module based on logical judgment, and according to the characteristics of the battery stack combined with the detection data of temperature, humidity and particle pollution, a weighted analysis is performed to comprehensively judge the gas harshness index in the cylindrical gas chamber; The badness index ( ) is a weighted sum based on temperature, humidity, and particle pollution concentration, and is calculated as follows: ； In the formula, temperature ( ),humidity( ) and particle pollution concentration ( ) is provided by the data acquisition module; temperature weight ( ) Humidity weight ( ) Particle pollution weight ( ) is determined by the characteristics of the fuel cell stack used, and is 1 / 3; is the normalized function of temperature, indicating the influence of temperature on the severity, and its value range is [0, 1]; is the normalized function of humidity, indicating the influence of humidity on the severity, with a value range of [0, 1]; is the normalized function of particle pollution, which indicates the impact of particle pollution on the severity, and its value range is [0, 1]; The temperature normalization function : ； in, and are the lower and upper limits of temperature, respectively. is the optimal temperature, which is determined by the characteristics of the battery stack; The temperature normalization function : ； in, It is the upper limit of humidity, which is determined by the characteristics of the battery stack; The particle contamination normalization function : ； in, It is the upper limit of particle pollution, which is determined by the characteristics of the battery stack; Generally, when the severity index ( ) exceeds 0.8, it is determined that the current working environment will affect the working life of the drone.

7. A hydrogen fuel cell drone control method according to claim 6, characterized in that: The risk management module is used to deal with the following three risks:

1. When the bad index ( ) exceeds 0.8 and exceeds 60 seconds, close the air inlet (5), give priority to supplying power to the flight control module and positioning module of the UAV, reduce or stop the power supply to non-critical components, start the built-in emergency oxygen cylinder (2) to provide pure oxygen to the main fuel cell (3), analyze the current positioning and average power consumption, if the set target can be achieved within half an hour, continue to perform the mission, if not, control the UAV to make an emergency landing and send out a distress signal; Second, when the main fuel cell (3) fails, the air inlet (5) is automatically closed, power is supplied to the flight control module and positioning module of the drone first, power supply to non-critical components is reduced or stopped, the built-in emergency oxygen cylinder (2) is activated to provide pure oxygen to the secondary fuel cell (4), and according to the formula The results are used to supply hydrogen and lithium batteries. The current positioning and average power consumption are analyzed. If the set target can be completed within half an hour, the mission will continue. If not, the drone will be controlled to make an emergency landing and send out a distress signal.

3. When the secondary fuel cell (4) fails partially, the system will try to increase its hydrogen supply to complete the original task. If the power of the hydrogen cannot meet the demand even if the hydrogen is increased to the maximum, the hydrogen supply of the main fuel cell (3) will be increased to make up for the missing power. The increased hydrogen supply is calculated according to the formula Calculated.

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