Low-temperature-resistant hydrogen energy unmanned aerial vehicle system capable of adapting to high-altitude flight

Abstract

The invention discloses a low-temperature-resistant hydrogen energy unmanned aerial vehicle system capable of adapting to high-altitude flight. The low-temperature-resistant hydrogen energy unmanned aerial vehicle system comprises an unmanned aerial vehicle body, a hydrogen energy fuel cell module, a driving module and a control module, the hydrogen energy fuel cell module generates electric energy through hydrogen and oxygen and provides the electric energy to the driving module, and the driving module drives the unmanned aerial vehicle body to fly; and the control module controls the hydrogen energy fuel cell module according to the flight height and the flight environment temperature of the unmanned aerial vehicle body and the residual hydrogen content in the hydrogen storage bottle, so that the hydrogen energy fuel cell module works in one of the following modes: an intelligent high-altitude oxygen supply mode, a weight-reduction endurance mode and a low-temperature-resistant mode. According to the invention, the problems of low temperature and low oxygen in high-altitude flight can be well solved, and the application prospect is wide; the control module can autonomously select an intelligent high-altitude oxygen supply mode, a weight-reduction endurance mode or a low-temperature-resistant mode to work according to the flight environment and the state of the unmanned aerial vehicle.

Description

Technical Field

[0001] The invention relates to the technical field of unmanned aerial vehicles, and in particular to a low-temperature-resistant hydrogen-powered unmanned aerial vehicle system that can adapt to high-altitude flight. Background Art

[0002] Unmanned Aerial Vehicle (UAV), also known as drone, is an unmanned aircraft controlled by a radio remote control device and a self-contained program control device, or operated completely or intermittently autonomously by an onboard computer. With the development of the drone industry, drones are being used more and more widely as tools in many fields. Nowadays, drones have played an important role in agriculture, military, industry, etc. However, the current drones powered by lithium batteries have a short battery life, which greatly limits their application. Using hydrogen energy as a power source for drones can greatly improve their endurance, and hydrogen energy is a clean energy source that is more environmentally friendly.

[0003] Fuel cells are clean power systems that use the reaction of hydrogen and oxygen to convert chemical energy into electrical energy. For every 1,000 meters increase in altitude, the atmospheric pressure drops by about 10KPa, the oxygen concentration drops by 1.5%, and the temperature drops by 6.5°C. Air-cooled fuel cells are used in drones. When flying at high altitudes, the performance of the fuel cell will be greatly reduced due to the dual decrease in oxygen concentration and ambient temperature.

[0004] Patent CN107585316A discloses a new energy hybrid power supply system for high-altitude unmanned aerial vehicles, which is equipped with a liquid oxygen tank as an oxygen source, and is used as an oxygen source for fuel cells when flying at high altitudes (flight altitude greater than 8km) to cope with the problem of hypoxia during high-altitude flight. However, it has the following shortcomings: (1) When the flight altitude is high but not greater than 8km, there may also be a problem of insufficient oxygen supply, but it has no relevant coping plan; the oxygen content is different at different altitudes, and it is impossible to make detailed adjustments to the oxygen supply according to the altitude; (2) adding a liquid oxygen tank as an oxygen source will increase the load, thereby increasing the consumption of the unmanned aerial vehicle and affecting the endurance; and when the flight altitude is always less than 8km or the flight altitude is greater than 8km and the journey is short, when the remaining fuel is exhausted, there may still be a large amount of oxygen source remaining, which causes a waste of load.

[0005] Patent CN110993986A discloses an air-cooled fuel cell high-altitude environmental adaptability adjustment device, which uses a turbocharger fan to increase the working pressure of the air in the cathode of the air-cooled fuel cell, thereby increasing the oxygen supply concentration and temperature of the cathode. However, increasing the oxygen supply by simply increasing the air intake volume has limited effect, especially when the oxygen concentration drops significantly or the temperature drops significantly.

[0006] Therefore, it is necessary to improve the existing technology to provide a more reliable solution. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a low-temperature resistant hydrogen energy UAV system that can adapt to high-altitude flight in view of the deficiencies in the above-mentioned prior art.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a low-temperature resistant hydrogen energy UAV system that can adapt to high-altitude flight, including a UAV body, a hydrogen energy fuel cell module, a drive module and a control module;

[0009] The hydrogen fuel cell module generates electrical energy through hydrogen and oxygen and provides electrical energy to the drive module, and the drive module drives the drone body to fly;

[0010] The control module controls the hydrogen fuel cell module according to the flight altitude of the drone body, the flight environment temperature, and the remaining hydrogen content in the hydrogen storage bottle, so that the hydrogen fuel cell module operates in one of the following modes: intelligent high-altitude oxygen supply mode, weight reduction endurance mode, and anti-low temperature mode.

[0011] Preferably, the hydrogen fuel cell module comprises: an air-cooled hydrogen fuel cell, a hydrogen supply unit, an air supply unit, an auxiliary oxygen supply unit and a heat exchanger;

[0012] The auxiliary oxygen supply unit adopts one of a pressurized oxygen supply mode and an oxygen storage bottle oxygen supply mode, or a combination of the two.

[0013] Among them, the pressurized oxygen supply method can be achieved by using equipment such as a turbocharger blower or a turbocharger fan, which increases the oxygen supply by increasing the air intake volume to meet the demand for high-altitude oxygen supply.

[0014] Among them, the oxygen supply method of oxygen storage bottles can be supplemented by adding pure oxygen supply equipment to assist in providing oxygen to meet the oxygen supply demand when the oxygen content at high altitude is too low.

[0015] Preferably, the hydrogen supply unit includes a hydrogen storage bottle, a hydrogen supply pipeline for transporting hydrogen in the hydrogen storage bottle to the hydrogen inlet of the air-cooled hydrogen fuel cell, a hydrogen supply solenoid valve arranged on the hydrogen supply pipeline, and a first pressure sensor for detecting the pressure in the hydrogen storage bottle;

[0016] The air supply unit includes a first air supply pipeline, an air inlet fan and a temperature sensor arranged at the inlet end of the first air supply pipeline, an air supply solenoid valve arranged on the first air supply pipeline, a heat exchanger connected to the outlet end of the first air supply pipeline, and a second air supply pipeline connecting the heat exchanger to the air inlet of the air-cooled hydrogen fuel cell; the outlet end of the first air supply pipeline is connected to the refrigerant inlet of the heat exchanger, and the inlet end of the second air supply pipeline is connected to the refrigerant outlet of the heat exchanger.

[0017] Preferably, a mixing pipe section is provided on the first air supply pipeline, and the auxiliary oxygen supply unit adopts an oxygen storage bottle oxygen supply method. The auxiliary oxygen supply unit includes an oxygen storage bottle, an oxygen supply pipeline for transporting oxygen in the oxygen storage bottle to the mixing pipe section, an oxygen supply solenoid valve arranged on the oxygen supply pipeline, and a second pressure sensor for detecting the pressure in the oxygen storage bottle.

[0018] Preferably, the air-cooled hydrogen fuel cell is provided with an exhaust gas emission pipe, and the exhaust gas emission pipe is connected to a first exhaust gas branch pipe and a second exhaust gas branch pipe in parallel, and the first exhaust gas branch pipe and the second exhaust gas branch pipe are respectively provided with a first exhaust gas solenoid valve and a second exhaust gas solenoid valve, the first exhaust gas branch pipe is connected to the heat medium inlet of the heat exchanger, the heat medium outlet of the heat exchanger is connected to the external environment, and the second exhaust gas branch pipe is connected to the mixing pipe section.

[0019] Preferably, in the intelligent high-altitude oxygen supply mode and the weight-reducing endurance mode, the first exhaust gas solenoid valve is opened and the second exhaust gas solenoid valve is closed; in the anti-low temperature mode, both the first exhaust gas solenoid valve and the second exhaust gas solenoid valve are opened.

[0020] Preferably, the method by which the control module controls the hydrogen fuel cell module to operate is:

[0021] S1. The control module periodically obtains the following parameters and then performs subsequent control according to the following parameters:

[0022] Get the current flight altitude H according to the GPS module on the drone body t ;

[0023] The temperature T of the air introduced into the hydrogen fuel cell module is obtained by the temperature sensor on the first air supply pipeline. t , T t As the flight environment temperature;

[0024] The current remaining hydrogen content Qs is obtained according to the pressure value in the hydrogen storage bottle detected by the first pressure sensor and the volume of the hydrogen storage bottle. H2 , and obtain the remaining hydrogen ratio η, η = remaining hydrogen content / initial total hydrogen storage capacity of the hydrogen storage bottle;

[0025] From the start of the flight to the current time, the average hydrogen consumption rate V tH2 , and calculate the oxygen consumption rate V that matches the complete reaction of hydrogen and oxygen tO2 ;

[0026] The remaining oxygen content Qs is obtained according to the pressure value in the oxygen storage bottle detected by the second pressure sensor and the volume of the oxygen storage bottle. O2 ;

[0027] S2, when T t ≥T min , and η≥(1 / 4-3 / 4), T min The temperature threshold is set in advance; the hydrogen fuel cell module is controlled to work in an intelligent high-altitude oxygen supply mode;

[0028] S3, when T t ≥T min , and η<(1 / 4-3 / 4), the hydrogen fuel cell module is controlled to operate in a weight-reducing endurance mode;

[0029] S4, when T t <T min When the temperature is low, the hydrogen fuel cell module is controlled to work in anti-low temperature mode.

[0030] Preferably, the method by which the control module controls the hydrogen fuel cell module to operate is:

[0031] S1. The control module periodically obtains the following parameters and then performs subsequent control according to the following parameters:

[0032] Get the current flight altitude H according to the GPS module on the drone body t ;

[0033] The temperature T of the air introduced into the hydrogen fuel cell module is obtained by the temperature sensor on the first air supply pipeline. t , T t As the flight environment temperature;

[0034] The current remaining hydrogen content Qs is obtained according to the pressure value in the hydrogen storage bottle detected by the first pressure sensor and the volume of the hydrogen storage bottle. H2 , and obtain the remaining hydrogen ratio η, η = remaining hydrogen content / initial total hydrogen storage capacity of the hydrogen storage bottle;

[0035] From the start of the flight to the current time, the average hydrogen consumption rate V tH2 , and calculate the oxygen consumption rate V that matches the complete reaction of hydrogen and oxygen tO2 ;

[0036] The remaining oxygen content Qs is obtained according to the pressure value in the oxygen storage bottle detected by the second pressure sensor and the volume of the oxygen storage bottle. O2 ;

[0037] S2, when T t ≥T min , and η≥(1 / 4-3 / 4), T min The temperature is a preset threshold value; the hydrogen fuel cell module is controlled to work in the intelligent high-altitude oxygen supply mode. The specific steps are as follows:

[0038] S2-1, first according to the current flight altitude H t , use the pre-built oxygen content and altitude comparison table to obtain the oxygen content at the current altitude, and then calculate the oxygen supply rate V at this time tO2 The required air supply rate V tAr ;

[0039] S2-2, if V tAr ≤maxV Ar , the air inlet fan and the air supply solenoid valve are controlled to supply air at a rate of V tAr Supply air to hydrogen fuel cell modules; maxV Ar is a preset air supply rate threshold;

[0040] Otherwise, the air supply rate is maxV Ar Supply air to the hydrogen fuel cell module, and at the same time make the oxygen storage bottle supply oxygen at a rate of V' tO2 Supply oxygen to the hydrogen fuel cell module; wherein the corresponding air supply rate is calculated based on the oxygen content at the current altitude as maxV Ar When the oxygen supply rate in the air is maxV O2 ; Satisfy: V' tO2 =V tO2 -maxV O2 ;

[0041] S3, when T t ≥T min , and η<(1 / 4-3 / 4), the hydrogen fuel cell module is controlled to work in a weight-reducing endurance mode. The specific steps are as follows:

[0042] S3-1, according to the average hydrogen consumption rate V tH2 and residual hydrogen content Qs H2 Calculate the estimated remaining battery life t x , t x =Qs H2 / V tH2 ; Then according to the residual oxygen content Qs O2 The remaining oxygen at tx The oxygen consumption rate V corresponding to the time consumed tXO2 , V tXO2 =Qs O2 / t x ;

[0043] S3-2, control the oxygen storage bottle to supply oxygen at a rate of V tXO2 Supply oxygen to the hydrogen fuel cell module, and at the same time supply air at a rate of V tXAr Supply air to the hydrogen fuel cell module; wherein the corresponding air supply rate is calculated according to the oxygen content at the current altitude as V tXAr When the oxygen supply rate V in the air tXAr-O2 ; then it satisfies: V tXAr-O2 =V tO2 -V tXO2 ; If V tXAr >maxV Ar , then use maxV Ar Replace V tXAr ;

[0044] S4, when T t <T min When the hydrogen fuel cell module is controlled to work in the anti-low temperature mode, the specific steps are as follows:

[0045] S4-1. Calculate the temperature difference index γ T ,

[0046] S4-2, control the air supply rate V according to the preset BAr supplying air to the hydrogen fuel cell module;

[0047] S4-3, the first exhaust solenoid valve and the second exhaust solenoid valve are both opened, so that the exhaust flow ratio in the second exhaust branch pipe and the first exhaust branch pipe is K1, where K1=γ T ×α, α is the tail gas ratio correction coefficient, which is a predetermined constant;

[0048] At the same time, the oxygen storage bottle is supplied with oxygen at a rate of V BO2 Supply oxygen to the hydrogen fuel cell module, where V BO2 =β×V BAr ×K1, β is the correction coefficient, which is a predetermined constant.

[0049] Preferably, α=0.01-0.75.

[0050] Preferably, β=0.25-2.

[0051] The beneficial effects of the present invention are:

[0052] The present invention provides a low-temperature-resistant hydrogen-powered UAV system that can adapt to high-altitude flight, which can well cope with the problems of low temperature and low oxygen during high-altitude flight and has broad application prospects.

[0053] The control module of the present invention can autonomously select intelligent high-altitude oxygen supply mode, weight reduction endurance mode or anti-low temperature mode to work according to the flight environment and the state of the drone itself;

[0054] In the intelligent high-altitude oxygen supply mode, the air supply rate can be intelligently increased according to the flight altitude so that the supplied oxygen can always meet the needs of the air-cooled hydrogen fuel cell, thereby ensuring the efficiency of the fuel cell and reducing the loss of hydrogen in the fuel cell;

[0055] In the weight-reducing endurance mode, the extra energy consumption of the drone caused by the oxygen tanks set for high-altitude flight can be reduced, thereby indirectly increasing the endurance of the drone;

[0056] In anti-low temperature mode, the aircraft can better cope with flights in high-altitude and low-temperature environments by intelligently controlling the recycling of part of the exhaust gas and coordinating with the auxiliary oxygen supply unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a principle block diagram of the low-temperature-resistant hydrogen-powered UAV system that can adapt to high-altitude flight according to the present invention;

[0058] Figure 2 is a principle block diagram of the hydrogen fuel cell module of the present invention;

[0059] Figure 3 This is a schematic structural diagram of a low-temperature-resistant hydrogen-powered UAV system that can adapt to high-altitude flight according to the present invention;

[0060] Figure 4 is a flow chart of a control method of a control module of the present invention;

[0061] Figure 5 is a specific flow chart of step S2;

[0062] Figure 6 is a specific flow chart of step S3;

[0063] Figure 7 This is a specific flow chart of step S4.

[0064] Description of reference numerals:

[0065] 1—UAV body;

[0066] 2—Hydrogen fuel cell module;

[0067] 21—air-cooled hydrogen fuel cell; 22—hydrogen supply unit; 23—air supply unit; 24—auxiliary oxygen supply unit; 25—heat exchanger;

[0068] 211—exhaust gas exhaust pipe; 212—first exhaust gas branch pipe; 213—second exhaust gas branch pipe; 214—first exhaust gas solenoid valve; 215—second exhaust gas solenoid valve;

[0069] 221—hydrogen storage bottle; 222—hydrogen supply pipeline; 223—hydrogen supply solenoid valve; 224—first pressure sensor;

[0070] 231 - first air supply pipeline; 232 - air inlet fan; 233 - temperature sensor; 234 - air supply solenoid valve; 235 - second air supply pipeline; 236 - mixing pipe section;

[0071] 241—oxygen storage bottle; 242—oxygen supply pipeline; 243—oxygen supply solenoid valve; 244—second pressure sensor;

[0072] 3—Drive module;

[0073] 4—Control module. DETAILED DESCRIPTION

[0074] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0075] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0076] Example 1

[0077] Reference Figure 1-3 , this embodiment provides a low-temperature resistant hydrogen energy UAV system that can adapt to high-altitude flight, including a UAV body 1, a hydrogen energy fuel cell module 2, a driving module 3 and a control module 4;

[0078] The hydrogen fuel cell module 2 generates electrical energy through hydrogen and oxygen and provides it to the driving module 3, which drives the drone body 1 to fly.

[0079] The drone body 1 is provided with necessary components such as a GPS module and a battery. The battery is mainly used to start the drone and to power related devices such as the GPS module. The hydrogen fuel cell module 2 can charge the battery.

[0080] In this embodiment, the hydrogen fuel cell module 2 includes: an air-cooled hydrogen fuel cell 21 , a hydrogen supply unit 22 , an air supply unit 23 , an auxiliary oxygen supply unit 24 and a heat exchanger 25 .

[0081] In this embodiment, the hydrogen supply unit 22 includes a hydrogen storage bottle 221, a hydrogen supply pipeline 222 for transporting the hydrogen in the hydrogen storage bottle 221 to the hydrogen inlet of the air-cooled hydrogen fuel cell 21, a hydrogen supply solenoid valve 223 arranged on the hydrogen supply pipeline 222, and a first pressure sensor 224 for detecting the pressure in the hydrogen storage bottle 221.

[0082] In this embodiment, the air supply unit 23 includes a first air supply pipeline 231, an air inlet fan 232 and a temperature sensor 233 arranged at the inlet end of the first air supply pipeline 231, an air supply solenoid valve 234 arranged on the first air supply pipeline 231, a heat exchanger 25 connected to the outlet end of the first air supply pipeline 231, and a second air supply pipeline 235 connecting the heat exchanger 25 to the air inlet of the air-cooled hydrogen fuel cell 21; the outlet end of the first air supply pipeline 231 is connected to the refrigerant inlet of the heat exchanger 25, and the inlet end of the second air supply pipeline 235 is connected to the refrigerant outlet of the heat exchanger 25.

[0083] The exhaust gas generated by the air-cooled hydrogen fuel cell 21 contains a large amount of waste heat. By exchanging heat between the exhaust gas and the supplied air, the air is heated, which can improve the efficiency of the fuel cell.

[0084] A mixing pipe section 236 is provided on the first air supply pipeline 231, and the auxiliary oxygen supply unit 24 includes an oxygen storage bottle 241, an oxygen supply pipeline 242 for transporting oxygen in the oxygen storage bottle 241 to the mixing pipe section 236, an oxygen supply solenoid valve 243 provided on the oxygen supply pipeline 242, and a second pressure sensor 244 for detecting the pressure in the oxygen storage bottle 241.

[0085] The control module 4 is communicatively connected with the first exhaust solenoid valve 214, the second exhaust solenoid valve 215, the hydrogen supply solenoid valve 223, the first pressure sensor 224, the air inlet fan 232, the temperature sensor 233, the air supply solenoid valve 234, the oxygen supply solenoid valve 243, the second pressure sensor 244, etc.

[0086] The function of the auxiliary oxygen supply unit 24 is: when the UAV is flying at high altitude, the air becomes thinner as the altitude increases, and the oxygen content will decrease. When the oxygen content is too low, while providing air to the air-cooled hydrogen fuel cell 21, it can also provide oxygen to the air-cooled hydrogen fuel cell 21 through the oxygen storage bottle 241, so as to adapt to the needs of high-altitude flight.

[0087] In this embodiment, an exhaust gas emission pipe 211 is provided on the air-cooled hydrogen fuel cell 21, and a first exhaust gas branch pipe 212 and a second exhaust gas branch pipe 213 are connected in parallel to the exhaust gas emission pipe 211. The first exhaust gas branch pipe 212 and the second exhaust gas branch pipe 213 are respectively provided with a first exhaust gas solenoid valve 214 and a second exhaust gas solenoid valve 215. The first exhaust gas branch pipe 212 is connected to the heat medium inlet of the heat exchanger 25, and the heat medium outlet of the heat exchanger 25 is connected to the external environment for discharge. The second exhaust gas branch pipe 213 is connected to the mixing pipe section 236.

[0088] The exhaust gas in the first exhaust branch pipe 212 enters the heat exchanger 25, exchanges heat with the supplied air, and recovers heat. The exhaust gas in the second exhaust branch pipe 213 flows back into the mixing pipe section 236, and enters the air-cooled hydrogen fuel cell 21 together with the supplied air. The main purpose is that: the heat exchange efficiency between the hot exhaust gas and the cold air of the heat exchanger 25 is limited, and the heat exchange efficiency when the hot exhaust gas and the cold air are directly mixed will be significantly greater than the heat exchange efficiency of the heat exchanger 25; the higher the flight altitude, the lower the temperature of the supply air introduced from the outside will be, and the heat recovered by the heat exchanger 25 may not be able to heat the air to a suitable temperature. At this time, by recycling part of the exhaust gas and introducing it into the supply air, the temperature of the mixed gas supplied to the air-cooled hydrogen fuel cell 21 can be increased, thereby meeting the temperature requirement of the supply air; due to the reduction of oxygen content caused by the introduction of exhaust gas, the oxygen supply requirement can be met by providing oxygen at the same time through the auxiliary oxygen supply unit 24, so that it can better adapt to high-altitude flight. In order to increase the air supply temperature, the conventional solution is usually to use a heater to heat the air supply, and a battery is required to power the heater, and a fuel cell is used to charge the battery. Compared with such solutions, the present invention can reduce the increase in load and cost caused by adding heaters, batteries and other equipment.

[0089] In addition, the exhaust gas also contains some unreacted hydrogen, which can be reused in this process, and the water vapor in the exhaust gas can also humidify the air, which can be beneficial to the operation of the air-cooled hydrogen fuel cell 21.

[0090] The control module 4 controls the hydrogen fuel cell module 2 according to the flight altitude of the drone body 1, the flight environment temperature, and the remaining hydrogen content in the hydrogen storage bottle 221, so that the hydrogen fuel cell module 2 operates in one of the following modes: intelligent high-altitude oxygen supply mode, weight reduction endurance mode, and anti-low temperature mode.

[0091] In the intelligent high-altitude oxygen supply mode and the weight-reducing endurance mode, the first exhaust gas solenoid valve 214 is opened and the second exhaust gas solenoid valve 215 is closed; in the anti-low temperature mode, both the first exhaust gas solenoid valve 214 and the second exhaust gas solenoid valve 215 are opened.

[0092] Reference Figure 4-7In this embodiment, the method in which the control module 4 controls the hydrogen fuel cell module 2 to work is:

[0093] S1. The control module 4 periodically obtains the following parameters, and then performs subsequent control according to the following parameters:

[0094] Get the current flight altitude H according to the GPS module on the drone body 1 t ;

[0095] The temperature T of the air introduced into the hydrogen fuel cell module 2 is obtained by the temperature sensor 233 on the first air supply pipeline 231 t , T t As the flight environment temperature;

[0096] The current remaining hydrogen content Qs is obtained according to the pressure value in the hydrogen storage bottle 221 detected by the first pressure sensor 224 and the volume of the hydrogen storage bottle 221 H2 , and obtain the residual hydrogen ratio η, η = residual hydrogen content / initial total hydrogen storage capacity of the hydrogen storage bottle 221;

[0097] From the start of the flight to the current time, the average hydrogen consumption rate V tH2 , and calculate the oxygen consumption rate V that matches the complete reaction of hydrogen and oxygen tO2 ; The average hydrogen consumption rate, oxygen consumption rate, and air supply rate, oxygen supply rate, etc. mentioned here, all refer to the supply or consumption of gas per unit time, and the units are the same;

[0098] The remaining oxygen content Qs is obtained according to the pressure value in the oxygen storage bottle 241 detected by the second pressure sensor 244 and the volume of the hydrogen storage bottle 221 O2 ;

[0099] S2, when T t ≥T min , and η≥1 / 2, T min is a preset temperature threshold (the threshold of the residual hydrogen ratio η is selected from 1 / 4 to 3 / 4, and can be adjusted within this range according to needs. For example, in this embodiment, the threshold is selected as 1 / 2; T min A conventional selection can be made according to specific needs. For example, in this embodiment, T min =-5°C; control the hydrogen fuel cell module 2 to work in the intelligent high-altitude oxygen supply mode,), the specific steps are as follows:

[0100] S2-1, first according to the current flight altitude H t , use the pre-built oxygen content and altitude comparison table (this comparison table can be obtained based on conventional public data) to obtain the oxygen content at the current altitude, and then calculate the oxygen supply rate V at this time tO2The required air supply rate V tAr ;

[0101] S2-2, if V tAr ≤maxV Ar , the air supply rate is V by controlling the air inlet fan 232 and the air supply solenoid valve 234. tAr Supply air to the hydrogen fuel cell module 2; maxV Ar is a preset air supply rate threshold, which is the maximum air supply rate that the air inlet fan 232 can provide;

[0102] Otherwise, the air supply rate is maxV Ar Air is supplied to the hydrogen fuel cell module 2, and at the same time, the oxygen storage bottle 241 is supplied with oxygen at a rate of V' tO2 Supply oxygen to the hydrogen fuel cell module 2; wherein the corresponding air supply rate is calculated based on the oxygen content at the current altitude as maxV Ar When the oxygen supply rate in the air is maxV O2 ; Satisfy: V' tO2 =V tO2 -maxV O2 ;

[0103] The higher the flight altitude, the lower the oxygen content will be, and the greater the amount of air required to obtain the same amount of oxygen; that is, the greater the air supply rate required to meet the same oxygen supply rate, if the air supply rate remains unchanged, the oxygen supplied to the air-cooled hydrogen fuel cell 21 will decrease, and the demand for hydrogen reaction will not be met, resulting in hydrogen loss. In the present invention, the air supply rate is intelligently increased according to the flight altitude so that the supplied oxygen can always meet the demand of the air-cooled hydrogen fuel cell 21, thereby ensuring the efficiency of the fuel cell and reducing the loss of hydrogen in the fuel cell.

[0104] If the flight altitude is too high, the air supply rate to meet the oxygen demand has exceeded the maximum air supply rate maxV that the air inlet fan 232 can provide. Ar When the maximum air supply rate maxV Ar The air is supplied to the air-cooled hydrogen fuel cell 21, and on the other hand, the oxygen supply difference, i.e. V', is provided by the oxygen storage bottle 241. tO2 ; This can further ensure the oxygen supply required for high-altitude flight.

[0105] S3, when T t ≥T min , and η<1 / 2, the hydrogen fuel cell module 2 is controlled to work in a weight-reducing endurance mode, and the specific steps are as follows:

[0106] S3-1, according to the average hydrogen consumption rate V tH2 and residual hydrogen content Qs H2 Calculate the estimated remaining battery life t x , t x =Qs H2 / V tH2 ; Then according to the residual oxygen content Qs O2 The remaining oxygen at t x The oxygen consumption rate V corresponding to the time consumed tXO2 , V tXO2 =Qs O2 / t x ;

[0107] S3-2, control the oxygen storage bottle 241 to supply oxygen at a rate of V tXO2 Oxygen is supplied to the hydrogen fuel cell module 2, and at the same time, the air supply rate is V tXAr Supply air to the hydrogen fuel cell module 2; wherein the corresponding air supply rate is calculated according to the oxygen content at the current altitude as V tXAr When the oxygen supply rate V in the air tXAr-O2 ; then it satisfies: V tXAr-O2 =V tO2 -V tXO2 ; If V tXAr >maxV Ar , then use maxV Ar Replace V tXAr ;

[0108] When η<1 / 2, it means that the remaining hydrogen content is only half of the full load, and it is necessary to adopt a strategy to increase the endurance; in the present invention, in order to adapt to the needs of high-altitude flight, in addition to using oxygen in the air as the oxygen supply for the air-cooled hydrogen fuel cell 21, a high-pressure oxygen storage bottle 241 is also equipped for oxygen supply. However, the oxygen in the high-pressure oxygen storage bottle 241 also has a certain weight, which will lead to energy consumption of the drone. In the control method of the present invention, when η≥1 / 2, the oxygen in the oxygen storage bottle 241 is only used under certain conditions. Therefore, at this time, there may be a large amount of oxygen remaining in the oxygen storage bottle 241. If it is not used, it will increase the energy consumption of the drone and shorten its endurance. In the present invention, this problem can be avoided by using a weight-reducing endurance mode:

[0109] First, the average hydrogen consumption rate V in the early stage of this flight is tH2 and residual hydrogen content Qs H2 Calculate the estimated remaining battery life t x Then, according to the remaining amount of oxygen in the oxygen storage bottle 241, it is calculated that all the oxygen will be used in the estimated remaining flight time t x The oxygen consumption rate VtXO2 , and according to the oxygen consumption rate V tXO2 The oxygen in the oxygen storage bottle 241 is supplied to the air-cooled hydrogen fuel cell 21, and the air supply rate V corresponding to the oxygen supply difference is calculated. tXAr-O2 , and supply air accordingly, so that the remaining flight time t x The remaining oxygen is completely used up in the air, which can reduce the extra energy consumption of the drone caused by the weight of oxygen, thereby indirectly increasing the endurance of the drone. tXAr >maxV Ar , indicating that the required air supply rate at this time exceeds the range that the air inlet fan 232 can provide, and the air inlet fan 232 can only work at its maximum air supply rate.

[0110] S4, when T t <T min When the hydrogen fuel cell module 2 is controlled to work in the anti-low temperature mode, the specific steps are as follows:

[0111] S4-1. Calculate the temperature difference index γ T ,

[0112] S4-2, control the air supply rate V according to the preset BAr Supply air to the hydrogen fuel cell module 2; V BAr It is a preset rated air supply rate under normal conditions and can be used as a reference value;

[0113] S4-3, the first exhaust solenoid valve 214 and the second exhaust solenoid valve 215 are both opened, so that the exhaust flow ratio in the second exhaust branch pipe 213 and the first exhaust branch pipe 212 is K1, wherein K1=γ T ×α, α is the tail gas ratio correction coefficient, which is a predetermined constant; α=0.01-0.75, and its specific value is determined in advance through experiments according to specific circumstances. For example, in one embodiment, α=0.35.

[0114] At the same time, the oxygen storage bottle 241 is supplied with oxygen at a rate of V BO2 Oxygen is supplied to the hydrogen fuel cell module 2, wherein V BO2 =β×V BAr ×K1, β is a correction coefficient, which is a predetermined constant, β=0.25-2, and its specific value is determined in advance through experiments according to specific circumstances. For example, in one embodiment, β=0.70.

[0115] T min is a preset temperature threshold. In this embodiment, T min = -5℃. When the current temperature is lower than Tmin , which means that the air temperature in the external environment is too low. It is difficult to heat the supplied air to a suitable temperature by simply heating it through the heat exchanger 25, which will affect the efficiency of the hydrogen fuel cell. At this time, part of the high-temperature exhaust gas is recycled and directly mixed into the supplied air. The heat exchange efficiency of direct mixed heating will be significantly greater than that of the heat exchanger 25, so that the supplied air can be heated to a higher temperature. The proportion of this part of the exhaust gas is related to the temperature difference index γ T There is a positive correlation, the temperature difference index γ T The larger the value, the higher the current temperature, indicating that more high-temperature exhaust gas needs to be recycled. The larger the value of K1, for a specific UAV system, the proportion of this part of the exhaust gas and the temperature difference index γ can be obtained by selecting the appropriate correction coefficient α through experiments in advance. T Relationship: K1 = γ T ×α;

[0116] The introduction of tail gas will reduce the oxygen in the supply air, so the auxiliary oxygen supply unit 24 is required to provide oxygen to the supply air at the same time to meet the needs of the air-cooled hydrogen fuel cell 21; the amount of oxygen provided by the auxiliary oxygen supply unit 24 is positively correlated with the tail gas flow ratio K1. The larger the value of K1, the more tail gas is recycled and the more oxygen is required; V BAr As a reference benchmark. For a specific UAV system, the oxygen supply rate V can be obtained by selecting an appropriate correction factor β through experiments in advance. BO2 The relationship between the exhaust gas flow ratio and K1 is: V BO2 =β×V BAr ×K1.

[0117] Through the anti-low temperature mode, the drone system of the present invention can better adapt to the flight in the high-altitude low-temperature environment. In the present invention, the above-mentioned parameter collection is performed periodically, and then the control is performed. For example, in this embodiment, the cycle is 3 minutes, that is, the parameters of the drone system are dynamically updated every 3 minutes, and the control of the hydrogen fuel cell module is dynamically adjusted according to the parameters, thereby improving the accuracy and effect of the control.

[0118] Battery life test

[0119] Test Example 1

[0120] The hydrogen energy UAV system of Example 1 was used for flight test, and the flight altitude was in the range of 1000-6000m, wherein a conventional multi-rotor UAV was used as the UAV body, and the main parameters were: take-off weight 30kg, wheelbase 1900mm, cruising speed 10m / s, climbing rate 4.5m / s, carrying hydrogen storage bottle volume 15L, oxygen bottle volume 7L; bottom surface ambient temperature 13°C. The flight time obtained by the test was 2.45h (three groups were tested under the same conditions, and the average value was taken as the result).

[0121] Test Example 2

[0122] The conditions are the same as those in test 1, except that: in the control method of the control module, the weight reduction endurance mode is not set, that is, there is no step S3, and the condition for using the intelligent high-altitude oxygen supply mode in step S2 is only: T t ≥T min The flight time obtained from the test is 2.14h (three groups were tested under the same conditions, and the average value was taken as the result). From the test results, it can be seen that the weight reduction endurance mode can effectively extend the endurance of the hydrogen energy UAV system.

[0123] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A low-temperature resistant hydrogen-powered UAV system that can adapt to high-altitude flight, characterized in that: It includes the drone body, hydrogen fuel cell module, drive module and control module; The hydrogen fuel cell module generates electrical energy through hydrogen and oxygen and provides the electrical energy to the driving module, and the driving module drives the drone body to fly; The control module controls the hydrogen fuel cell module according to the flight altitude of the drone body, the flight environment temperature, and the remaining hydrogen content in the hydrogen storage bottle, so that the hydrogen fuel cell module operates in one of the following modes: intelligent high-altitude oxygen supply mode, weight reduction endurance mode, and anti-low temperature mode.

2. The low-temperature-resistant hydrogen-powered UAV system that can adapt to high-altitude flight according to claim 1 is characterized in that: The hydrogen fuel cell module comprises: an air-cooled hydrogen fuel cell, a hydrogen supply unit, an air supply unit, an auxiliary oxygen supply unit and a heat exchanger; The auxiliary oxygen supply unit adopts one of a pressurized oxygen supply mode and an oxygen storage bottle oxygen supply mode, or a combination of the two.

3. The low-temperature-resistant hydrogen-powered UAV system that can adapt to high-altitude flight according to claim 2 is characterized in that: The hydrogen supply unit includes a hydrogen storage bottle, a hydrogen supply pipeline for transporting hydrogen in the hydrogen storage bottle to the hydrogen inlet of the air-cooled hydrogen fuel cell, a hydrogen supply solenoid valve arranged on the hydrogen supply pipeline, and a first pressure sensor for detecting the pressure in the hydrogen storage bottle.

4. The low-temperature-resistant hydrogen-powered UAV system capable of adapting to high-altitude flight according to claim 3 is characterized in that: The air supply unit comprises a first air supply pipeline, an air inlet fan and a temperature sensor arranged at the inlet end of the first air supply pipeline, an air supply solenoid valve arranged on the first air supply pipeline, a heat exchanger connected to the outlet end of the first air supply pipeline, and a second air supply pipeline connecting the heat exchanger to the air inlet of the air-cooled hydrogen fuel cell; the outlet end of the first air supply pipeline is connected to the refrigerant inlet of the heat exchanger, and the inlet end of the second air supply pipeline is connected to the refrigerant outlet of the heat exchanger; A mixing pipe section is provided on the first air supply pipeline, and the auxiliary oxygen supply unit adopts an oxygen storage bottle to supply oxygen. The auxiliary oxygen supply unit includes an oxygen storage bottle, an oxygen supply pipeline for transporting oxygen in the oxygen storage bottle to the mixing pipe section, an oxygen supply solenoid valve arranged on the oxygen supply pipeline, and a second pressure sensor for detecting the pressure in the oxygen storage bottle.

5. The low-temperature-resistant hydrogen-powered UAV system that can adapt to high-altitude flight according to claim 4 is characterized in that: The air-cooled hydrogen fuel cell is provided with an exhaust gas emission pipe, and the exhaust gas emission pipe is connected to a first exhaust gas branch pipe and a second exhaust gas branch pipe in parallel, and the first exhaust gas branch pipe and the second exhaust gas branch pipe are respectively provided with a first exhaust gas solenoid valve and a second exhaust gas solenoid valve, the first exhaust gas branch pipe is connected to the heat medium inlet of the heat exchanger, the heat medium outlet of the heat exchanger is connected to the external environment, and the second exhaust gas branch pipe is connected to the mixing pipe section.

6. The low-temperature-resistant hydrogen-powered UAV system capable of adapting to high-altitude flight according to claim 5 is characterized in that: In the intelligent high-altitude oxygen supply mode and weight reduction endurance mode, the first exhaust gas solenoid valve is opened and the second exhaust gas solenoid valve is closed; in the anti-low temperature mode, both the first exhaust gas solenoid valve and the second exhaust gas solenoid valve are opened.

7. The low-temperature-resistant hydrogen-powered UAV system capable of adapting to high-altitude flight according to claim 6 is characterized in that: The method for the control module to control the hydrogen fuel cell module to work is: S1. The control module periodically obtains the following parameters and then performs subsequent control according to the following parameters: Get the current flight altitude H according to the GPS module on the drone body t ; The temperature T of the air introduced into the hydrogen fuel cell module is obtained by the temperature sensor on the first air supply pipeline. t , T t As the flight environment temperature; The current remaining hydrogen content Qs is obtained according to the pressure value in the hydrogen storage bottle detected by the first pressure sensor and the volume of the hydrogen storage bottle. H2 , and obtain the remaining hydrogen ratio η, η = remaining hydrogen content / initial total hydrogen storage capacity of the hydrogen storage bottle; From the start of the flight to the current time, the average hydrogen consumption rate V tH2 , and calculate the oxygen consumption rate V that matches the complete reaction of hydrogen and oxygen tO2 ; The remaining oxygen content Qs is obtained according to the pressure value in the oxygen storage bottle detected by the second pressure sensor and the volume of the oxygen storage bottle. O2 ; S2, when T t ≥T min , and η≥(1 / 4-3 / 4), T min The temperature threshold is set in advance; the hydrogen fuel cell module is controlled to work in an intelligent high-altitude oxygen supply mode; S3, when T t ≥T min , and η<(1 / 4-3 / 4), the hydrogen fuel cell module is controlled to operate in a weight-reducing endurance mode; S4, when T t <T min When the temperature is low, the hydrogen fuel cell module is controlled to work in anti-low temperature mode.

8. The low-temperature-resistant hydrogen-powered UAV system capable of adapting to high-altitude flight according to claim 7 is characterized in that: The method for the control module to control the hydrogen fuel cell module to work is: S1. The control module periodically obtains the following parameters and then performs subsequent control according to the following parameters: Get the current flight altitude H according to the GPS module on the drone body t ; The temperature T of the air introduced into the hydrogen fuel cell module is obtained by the temperature sensor on the first air supply pipeline. t , T t As the flight environment temperature; The current remaining hydrogen content Qs is obtained according to the pressure value in the hydrogen storage bottle detected by the first pressure sensor and the volume of the hydrogen storage bottle. H2 , and obtain the remaining hydrogen ratio η, η = remaining hydrogen content / initial total hydrogen storage capacity of the hydrogen storage bottle; From the start of the flight to the current time, the average hydrogen consumption rate V tH2 , and calculate the oxygen consumption rate V that matches the complete reaction of hydrogen and oxygen tO2 ; The remaining oxygen content Qs is obtained according to the pressure value in the oxygen storage bottle detected by the second pressure sensor and the volume of the oxygen storage bottle. O2 ; S2, when T t ≥T min , and η≥(1 / 4-3 / 4), T min The temperature is a preset threshold value; the hydrogen fuel cell module is controlled to work in the intelligent high-altitude oxygen supply mode. The specific steps are as follows: S2-1, first according to the current flight altitude H t , use the pre-built oxygen content and altitude comparison table to obtain the oxygen content at the current altitude, and then calculate the oxygen supply rate V at this time tO2 The required air supply rate V tAr ; S2-2, if V tAr ≤maxV Ar , the air inlet fan and the air supply solenoid valve are controlled to supply air at a rate of V tAr Supply air to hydrogen fuel cell modules; maxV Ar is a preset air supply rate threshold; Otherwise, the air supply rate is maxV Ar Supply air to the hydrogen fuel cell module, and at the same time make the oxygen storage bottle supply oxygen at a rate of V' tO2 Supply oxygen to the hydrogen fuel cell module; wherein the corresponding air supply rate is calculated based on the oxygen content at the current altitude as maxV Ar When the oxygen supply rate in the air is maxV O2 ; Satisfy: V' tO2 =V tO2 -maxV O2 ; S3, when T t ≥T min , and η<(1 / 4-3 / 4), the hydrogen fuel cell module is controlled to work in a weight-reducing endurance mode. The specific steps are as follows: S3-1, according to the average hydrogen consumption rate V tH2 and residual hydrogen content Qs H2 Calculate the estimated remaining battery life t x , t x =Qs H2 / V tH2 ; Then according to the residual oxygen content Qs O2 The remaining oxygen at t x The oxygen consumption rate V corresponding to the time consumed tXO2 , V tXO2 =Qs O2 / t x ; S3-2, control the oxygen storage bottle to supply oxygen at a rate of V tXO2 Supply oxygen to the hydrogen fuel cell module, and at the same time supply air at a rate of V tXAr Supply air to the hydrogen fuel cell module; wherein the corresponding air supply rate is calculated according to the oxygen content at the current altitude as V tXAr When the oxygen supply rate V in the air tXAr-O2 ; then it satisfies: V tXAr-O2 =V tO2 -V tXO2 ; If V tXAr >maxV Ar , then use maxV Ar Replace V tXAr ; S4, when T t <T min When the hydrogen fuel cell module is controlled to work in the anti-low temperature mode, the specific steps are as follows: S4-1. Calculate the temperature difference index γ T , S4-2, control the air supply rate V according to the preset BAr supplying air to the hydrogen fuel cell module; S4-3, the first exhaust solenoid valve and the second exhaust solenoid valve are both opened, so that the exhaust flow ratio in the second exhaust branch pipe and the first exhaust branch pipe is K1, where K1=γ T ×α, α is the tail gas ratio correction coefficient, which is a predetermined constant; At the same time, the oxygen storage bottle is supplied with oxygen at a rate of V BO2 Supply oxygen to the hydrogen fuel cell module, where V BO2 =β×V BAr ×K1, β is the correction coefficient, which is a predetermined constant.

9. The low-temperature-resistant hydrogen-powered UAV system capable of adapting to high-altitude flight according to claim 8 is characterized in that: α＝0.01-0.75。 10. The low-temperature-resistant hydrogen-powered UAV system capable of adapting to high-altitude flight according to claim 8 is characterized in that: β＝0.25-2。

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