Unmanned aerial vehicle hydrogen-electricity hybrid power system and energy management method

Abstract

The unmanned aerial vehicle hydrogen-electricity hybrid power system comprises a vehicle body, a hydrogen fuel cell system, a power cell system and an energy management system are arranged in the vehicle body, and electric energy output by the hydrogen fuel cell system and the power cell system supplies power to a motor through the energy management system; the motor controls the spiral blades, the rotating speed of the motor is independently adjusted, and the posture and movement of the unmanned aerial vehicle are controlled by changing the direction and size of the lifting force; the energy management system is used for performing energy conversion during air speed change and braking of the unmanned aerial vehicle, converting mechanical energy into electric energy, inputting the electric energy into the power battery system, and meanwhile, converting the electric energy to judge whether the unmanned aerial vehicle has a high-power energy supply demand currently so as to adjust energy supply; according to the invention, the service life of the galvanic pile monomers can be prolonged, so that the service life of the hydrogen-electricity hybrid power system module can be prolonged; according to the energy management method, unnecessary energy loss is reduced, and the endurance time of the unmanned aerial vehicle is further prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned aerial vehicle (UAV) energy management, and particularly relates to a UAV hydrogen-electric hybrid power system and an energy management method. Background Art

[0002] With the continuous development of technology, the hydrogen-electric hybrid power system combines the advantages of hydrogen fuel cells and battery technologies, aiming to solve the complexity problems existing in traditional fuel cell systems, such as power density requirements, adaptability of hydrogen and air, and energy loss. This system realizes energy storage, power balance, and range extension through electric-electric hybrid technology, thereby improving the overall performance and economy. As an important energy utilization system, the hydrogen-electric hybrid power system has been widely applied in various fields. For example, in common electric UAVs, the hydrogen-electric hybrid power system serves as the power source of the electric UAV and plays an important role in the service performance such as the endurance of the electric UAV.

[0003] The hydrogen-electric composite power UAV uses a hydrogen fuel cell as the main energy supply component (Deng Shuhao, Lei Tao, Jin Xianqiu, et al. Stability and power control method of fuel cell UAV hybrid power system [J]. Acta Aeronautica et Astronautica Sinica, 2024, 45(17): 146-162.). There are multiple stacks in the hydrogen fuel cell, and multiple stack monomers are connected to each other to supply energy to the UAV. At the same time, a lithium battery pack is also arranged in the hydrogen-electric composite power system for auxiliary energy supply under high loads. However, when using the above hydrogen-electric composite power supply module, since the hydrogen fuel cell generally serves as the main source of the UAV energy supply system, and due to the complexity of the UAV's maneuvering attitude and the low efficiency of energy conversion, it inevitably leads to low energy utilization rate of the UAV. In addition, the external environment obstacles encountered by the UAV during aerial maneuvers have a greater impact on the UAV. Generally, the UAV energy management method adjusts the energy supply ratio of the hydrogen fuel cell and the lithium battery by judging the current remaining power of the lithium battery (Zhang Yan, et al., Online energy management strategy based on the optimization of fuel cell UAV SOC fluctuation, IEEE Transactions on Transportation Electrification, Vol. 10, No. 2, pp. 3105-3113, June 2024), lacking the information transmission function of real-time monitoring and feedback on the damping impact brought by the external environment where the UAV is located, inevitably resulting in the UAV lacking the ability to judge real-time power demand and large energy loss. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a UAV hydrogen-electric hybrid power system and an energy management method, which can improve the service life of the stack monomers, and thus can improve the service life of the hydrogen-electric hybrid power system module; the energy management method reduces unnecessary energy loss and further improves the endurance of the UAV.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A hydrogen-electric hybrid power system for an unmanned aerial vehicle, comprising an airframe 6, in which a hydrogen fuel cell system 33, a power battery system 34 and an energy management system 36 are arranged. The electric energy output by the hydrogen fuel cell system 33 and the power battery system 34 is supplied to the motor 21 through the energy management system 36; the motor 21 controls the propeller blades 1, and the rotation speed of the motor 21 is independently adjusted. By changing the direction and magnitude of the lift force, the attitude and movement of the unmanned aerial vehicle are controlled.

[0007] The hydrogen fuel cell system 33 includes a hydrogen storage tank 7. The inlet end of the hydrogen storage tank 7 is connected to a hydrogen injection port 5 located on the airframe 6 through a fluid pipeline. The outlet end of the hydrogen storage tank 7 is connected to the hydrogen inlet of a humidifier 9 through a switch valve 10. The hydrogen outlet of the humidifier 9 is connected to a hydrogen fuel cell 13; a gas storage cylinder 8 is connected to the air inlet of the humidifier 9 through an air output pipeline, and the air outlet of the humidifier 9 is connected to the hydrogen fuel cell 13. Hydrogen and air perform a combustion operation in the hydrogen fuel cell 13.

[0008] The power battery system 34 includes a lithium battery 15. The lithium battery 15 is an all-weather high-rate lithium battery. The lithium battery 15 is connected to a bus module 18 through a first DC-DC converter 17. The hydrogen fuel cell 13 is connected to the bus module 18 through a second DC-DC converter 35. The low-voltage current generated by the hydrogen fuel cell 13 is boosted by the second DC-DC converter 35 to a high voltage and input into the bus module 18. On the one hand, the first DC-DC converter 17 boosts the low-voltage current from the lithium battery 15 to input into the bus module 18. On the other hand, the first DC-DC converter 17 steps down the high-voltage current from the bus module 18 to input into the lithium battery 15 for storage; the bus module 18 converts the direct current into alternating current through a DC-AC converter 19 and then transports it to a power supply controller 20 in the energy management system 36. The power supply controller 20 transports the electric energy to other power-consuming modules including a water pump 12 and a motor 21 inside the airframe 6.

[0009] The described energy management system 36 includes a heat dissipation energy management system and an energy collection system; the heat dissipation energy management system includes a passive air-cooled heat dissipation structure and an active heat dissipation system; the passive air-cooled heat dissipation structure is located on the body 6 close to the hydrogen fuel cell 13, the heat sink is designed as a stacked fin structure, the material is aluminum alloy, and after being stamped into fins, they are stacked and fixed; the active heat dissipation system includes a heat exchanger 11, the heat exchanger 11 exchanges heat with the hydrogen fuel cell 13 through a cooling pipeline, the heat exchanger 11 is connected to the water tank 14 through a water pump 12, and the water tank 14 is arranged inside the body 6; an installation groove is arranged on the body 6 close to the hydrogen fuel cell 13, and the cooling pipeline is laid in the installation groove; secondly, a control device and a temperature sensor are also arranged on the body 6 close to the hydrogen fuel cell 13, the number of temperature sensors is the same as the number of stacks in the hydrogen fuel cell 13, and each temperature sensor corresponds to a stack in a hydrogen fuel cell 13 respectively.

[0010] The energy collection system includes an energy collector arranged inside the water tank 14, and the energy collector is connected to a power supply controller 20; the energy collector includes a piezoelectric energy collector, a mechanical resonator, and a linear reciprocating electromagnetic generator; the piezoelectric energy collector includes a support plate 22, the upper part of the support plate 22 is connected to the top of the water tank 14, the lower part of the support plate 22 is vertically connected to the upper end of a connecting rod 23, the upper part of the connecting rod 23 is connected to a force amplifier 27, the force amplifier 27 includes two V-shaped bent plates 31 arranged horizontally up and down and two rectangular acting plates 32 arranged vertically left and right connected thereto, the V-shaped bent plates 31 are arranged along the vertical direction of the angle bisector of the included angle, a sliding rod 24 is arranged on the sliding rod 24, and a mass block 25 is connected to the sliding rod 24, and the mass block 25 and the sliding rod 24 form a moving pair; along the horizontal direction, one end of a piezoelectric ceramic material 26 is connected to the mass block 25, and the other end is connected to the rectangular acting plate 32;

[0011] The mechanical resonator includes an elastic spring 28 and a resonant mass block 29, the lower V-shaped bent plate 31 in the force amplifier 27 is connected to the resonant mass block 29 through the elastic spring 28, and a limiter 30 is arranged at the port of the connecting rod 23 close to the resonant mass block 29;

[0012] The described resonant mass block 29 is set as a coil motor, the lower end of the connecting rod 23 is a magnetic axis formed by the like-sex magnetic poles approaching each other, and the lower end magnetic axis of the connecting rod 23, the elastic spring 28, and the resonant mass block 29 together form a linear reciprocating electromagnetic generator.

[0013] The piezoelectric ceramic material 26 is in the shape of an arc with irregular curvature, and the curve curvature gradually increases along the direction from the rectangular acting plate 32 to the mass block 25. The piezoelectric ceramic material 26 is designed with bistability, and there is a piezoelectric ceramic material 26 on each of the left and right sides of the mass block 25, and the two are mirror-symmetrical.

[0014] An energy management method for a hydrogen-electric hybrid power system of an unmanned aerial vehicle, comprising:

[0015] After the drone is ready for takeoff and completes the system self-check, if the hydrogen fuel cell 13 is in normal condition, the hydrogen fuel cell 13 is started and preheated, otherwise an alarm is triggered and the process is terminated; during the drone takeoff phase, the lithium battery 15 instantly supplies power, and then the current takeoff altitude of the drone is judged. If the takeoff altitude reaches the threshold, the energy management system switches the hydrogen fuel cell 13 to continuously supply power, otherwise the lithium battery 15 continues to be used as the main power supply; when the hydrogen fuel cell 13 is continuously supplying power, the drone ends the initial takeoff phase and triggers the normal power supply demand, and then judges whether there is a high power demand at this stage. If so, the lithium battery 15 is introduced as the main power supply device and The remaining power of the lithium battery 15 is evaluated. If the remaining power of the lithium battery 15 is lower than the threshold, the system is requested to intervene with the hydrogen fuel cell 13 for the main power supply. If the system responds to a fault, an alarm is issued and the process is terminated. If there is no high power demand at this stage, the hydrogen fuel cell 13 continues to be used as the power supply equipment; when the hydrogen fuel cell 13 is the main power supply, the system evaluates the output status of the hydrogen fuel cell 13 in real time. If the output status of the hydrogen fuel cell 13 is stable, it switches to the hybrid power supply mode. In the hybrid power supply mode, the UAV adopts a power supply mode in which the hydrogen fuel cell 13 is the main power supply and the lithium battery 15 is the auxiliary power supply. Otherwise, if it is unstable, an alarm is issued and an emergency landing is taken.

[0016] In the hybrid power supply mode, the energy management system 36 intervenes and first performs a threshold judgment on the converted electric energy output by the piezoelectric energy harvester. If the converted electric energy exceeds the threshold, it means that the damping effect of the external environment of the current body is relatively large and there is a high-power power supply demand at this stage. The power supply strategy is adjusted through the energy management system 36. At the same time, the electric energy converted by the piezoelectric energy harvester and the linear reciprocating electromagnetic generator is transmitted to the lithium battery 15 for storage after passing through the first DC-DC converter 17.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] Since the drone adopts a hydrogen-electric hybrid power system, it has significant advantages over traditional pure battery or fuel power batteries in terms of endurance, environmental adaptability, energy replenishment efficiency, and economy. The hydrogen fuel cell 13 continuously supplies power through the combustion reaction of hydrogen, and at the same time, it is paired with a lithium battery 15 to meet instantaneous high-power demands, avoiding the problem of capacity attenuation of pure lithium batteries. The hydrogen-electric hybrid power system can provide the drone with several hours or even dozens of hours of endurance, far exceeding that of pure lithium battery drones of the same weight. Further, the hydrogen fuel cell 13 has excellent low-temperature performance and can operate stably between -20°C and 40°C, and also has good operating effects in high-altitude and strong vibration environments; the lithium battery 15 and the hydrogen fuel cell 13 are respectively connected through the first DC-DC converter 17 and the second DC-DC converter 35 and the bus module 18, and the power controller 20 in the energy management system 36 regulates the energy conversion and transmission of each device, effectively improving the energy utilization efficiency of the drone.

[0019] Since the energy management system 36 in the present invention includes a piezoelectric energy harvester and a mechanical resonator, the resonant mass block 29 in the mechanical resonator moves up and down along the connecting rod 23 under the influence of the vibration generated when the drone maneuvers, and drives the piezoelectric ceramic material 26 in the piezoelectric energy harvester to deform. Further, the piezoelectric energy harvester generates converted electrical energy that is positively correlated with the current vibration amplitude of the drone. This converted electrical energy is used for the drone to analyze the damping effect brought by the current external environment and determine whether there is a high-power demand at present, which can be used as an effective energy management method.

[0020] The energy management system 36 of the present invention includes a heat dissipation energy management system, and the heat dissipation energy management system includes a passive air-cooled heat dissipation structure and an active heat dissipation system. When the temperature of the hydrogen fuel cell 13 stack is too high, heat exchange can be carried out on the stack monomer with higher heat generation through the heat exchanger 11 to maintain temperature balance, thereby improving the service life of the stack monomer and further improving the service life of the hydrogen fuel cell 13.

[0021] The energy harvesting system of the present invention includes an energy harvester, and the energy harvester includes a piezoelectric energy harvester, a mechanical resonator, and a linear reciprocating electromagnetic generator; by converting the vibration energy during the maneuver of the drone, the obtained electrical energy is input into the lithium battery 15 through the power controller 20 for storage, increasing the endurance time of the drone. Description of the Drawings

[0022] Figure 1 is the overall diagram of a hydrogen-electric hybrid power system of a drone according to an embodiment of the present invention.

[0023] Figure 2 is the connection schematic diagram of the hydrogen-electric hybrid power system of the drone according to an embodiment of the present invention.

[0024] Figure 3 It is a schematic diagram of the piezoelectric energy harvester according to an embodiment of the present invention.

[0025] Figure 4 It is a schematic diagram of the energy conversion of the hydrogen-electric hybrid power system of the unmanned aerial vehicle according to an embodiment of the present invention.

[0026] Figure 5 It is a schematic flow diagram of the energy management system according to an embodiment of the present invention.

[0027] In the figure: 1 - fixed-wing propeller blade, 2 - bearing, 3 - rotating rod, 4 - movable wing joint, 5 - hydrogen injection port, 6 - airframe, 7 - hydrogen storage tank, 8 - gas storage cylinder, 9 - humidifier, 10 - switch valve, 11 - heat exchanger, 12 - water pump, 13 - hydrogen fuel cell, 14 - water tank, 15 - lithium battery, 17 - first DC-DC converter, 18 - bus module, 19 - DC-AC converter, 20 - power controller, 21 - motor, 22 - support plate, 23 - connecting rod, 24 - sliding rod, 25 - mass block, 26 - piezoelectric ceramic material, 27 - force amplifier, 28 - elastic spring, 29 - resonant mass block, 30 - limiter, 31 - V-shaped bending plate, 32 - rectangular acting plate, 33 - hydrogen fuel cell system, 34 - power battery system, 35 - second DC-DC converter, 36 - energy management system. Detailed implementation manners

[0028] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] As Figure 1 、 Figure 2 shown, a hydrogen-electric hybrid power system for an unmanned aerial vehicle includes an airframe 6. A rotating rod 3 is installed around the airframe 6. The rotating rod 3 is connected to a movable wing joint 4 through a bolt pair. An electric motor 21 is arranged above the movable wing joint 4. The electric motor 21 is connected to a propeller blade 1 through a bearing 2. The propeller blade 1 is controlled by the electric motor 21, and the rotation speed of the electric motor 21 is independently adjusted. By changing the direction and magnitude of the lift force, the attitude and movement of the unmanned aerial vehicle are controlled. A hydrogen fuel cell system 33, a power battery system 34 and an energy management system 36 are arranged inside the airframe 6. The electric energy output by the hydrogen fuel cell system 33 and the power battery system 34 is supplied to the electric motor 21 through the energy management system 36.

[0030] The hydrogen fuel cell system 33 described above includes a hydrogen storage tank 7, a gas cylinder 8, a humidifier 9, a hydrogen fuel cell 13 and its related accessories. The inlet end of the hydrogen storage tank 7 is connected to the hydrogen injection port 5 on the airframe 6 through a fluid pipeline. The outlet end of the hydrogen storage tank 7 is connected to the hydrogen inlet of the humidifier 9 through a switch valve 10. The hydrogen outlet of the humidifier 9 is connected to the hydrogen fuel cell 13. Additionally, part of the air delivery fluid pipeline is connected to the gas cylinder 8 and part is directly communicated with the outside of the airframe 6. Different fluid pipelines are independent of each other and do not affect each other. The gas cylinder 8 is connected to the air inlet of the humidifier 9 through an air output pipeline, and the air outlet of the humidifier 9 is connected to the hydrogen fuel cell 13. Hydrogen and air perform a combustion operation in the hydrogen fuel cell 13.

[0031] The power battery system 34 described above includes a lithium battery 15, a first DC-DC converter 17, a second DC-DC converter 35, a bus module 18, a DC-AC converter 19 and its related accessories. The lithium battery 15 is an all-weather high-rate lithium battery to meet the various complex environments faced by the UAV. The lithium battery 15 is connected to the bus module 18 through the first DC-DC converter 17. The hydrogen fuel cell 13 is connected to the bus module 18 through the second DC-DC converter 35. The low-voltage current generated by the hydrogen fuel cell 13 is boosted to a high voltage through the second DC-DC converter 35 and input into the bus module 18. On the one hand, the first DC-DC converter 17 can boost the low-voltage current from the lithium battery 15 to input it into the bus module 18. On the other hand, the first DC-DC converter 17 can step down the high-voltage current from the bus module 18 to input it into the lithium battery 15 for storage. The bus module 18 converts the direct current into alternating current through the DC-AC converter 19 and then transports it to the power supply controller 20 in the energy management system 36. The power supply controller 20 delivers the electric energy to other power-consuming modules including a water pump 12 and a motor 21 inside the airframe 6.

[0032] The energy management system 36 described above includes a heat dissipation energy management system and an energy collection system. The heat dissipation energy management system includes a passive air-cooled heat dissipation structure and an active heat dissipation system. The passive air-cooled heat dissipation structure is located on the airframe 6 near the hydrogen fuel cell 13. The heat sink is designed as a stacked fin structure, made of aluminum alloy, and stacked and fixed after being stamped into fins. The active heat dissipation system includes a heat exchanger 11, a water pump 12, and a water tank 14. The heat exchanger 11 exchanges heat with the hydrogen fuel cell 13 through a cooling pipeline. The heat exchanger 11 is connected to the water tank 14 through the water pump 12. The water tank 14 is arranged inside the airframe 6. An installation groove is arranged on the airframe 6 near the hydrogen fuel cell 13, and the cooling pipeline is laid in the installation groove. Secondly, a control device and a temperature sensor are also provided inside the airframe 6 near the hydrogen fuel cell 13. The number of temperature sensors is the same as the number of stacks in the hydrogen fuel cell 13, and each temperature sensor corresponds to a stack in a hydrogen fuel cell 13 respectively.

[0033] Referring to Figure 3 , the energy harvesting system includes an energy harvester disposed inside a water tank 14, and the energy harvester is connected to a power supply controller 20; the energy harvester includes a piezoelectric energy harvester, a mechanical resonator, and a linear reciprocating electromagnetic generator; the piezoelectric energy harvester includes a support plate 22, a connecting rod 23, a sliding rod 24, a mass block 25, a piezoelectric ceramic material 26, and a force amplifier 27. The upper part of the support plate 22 is connected to the top of the water tank 14, the lower part of the support plate 22 is vertically connected to the upper end of the connecting rod 23, the upper part of the connecting rod 23 is connected to the force amplifier 27. The force amplifier 27 includes two V-shaped bent plates 31 arranged horizontally up and down and two rectangular acting plates 32 arranged vertically left and right and connected thereto. The V-shaped bent plates 31 are arranged along the vertical direction of the angle bisector of the included angle, and a sliding rod 24 is arranged thereon. A mass block 25 is connected to the sliding rod 24. The mass block 25 and the sliding rod 24 form a moving pair and can move up and down along the sliding rod 24. Horizontally, one end of the piezoelectric ceramic material 26 is connected to the mass block 25, and the other end is connected to the rectangular acting plate 32. The piezoelectric ceramic material 26 is in the shape of an arc with irregular curvature, and the curve curvature gradually increases along the direction from the rectangular acting plate 32 to the mass block 25. The piezoelectric ceramic material 26 is designed with bistability. There is a piezoelectric ceramic material 26 on each of the left and right sides of the mass block 25, and the two are mirror-symmetrical;

[0034] The mechanical resonator includes an elastic spring 28, a resonant mass block 29, and a limiter 30. The lower V-shaped bent plate 31 in the force amplifier 27 is connected to the resonant mass block 29 through the elastic spring 28, and a limiter 30 is arranged at the port of the connecting rod 23 near the resonant mass block 29.

[0035] The resonant mass block 29 is set as a coil motor. The lower end of the connecting rod 23 is a magnetic axis formed by the like poles approaching each other. The lower end magnetic axis of the connecting rod 23, the elastic spring 28, and the resonant mass block 29 together form a linear reciprocating electromagnetic generator.

[0036] Referring to Figure 3, when the drone performs maneuvering operations, the airframe 6 vibrates. At the same time, due to the influence of the water fluid stored inside the water tank 14, this vibration is further amplified. At this time, the resonant mass 29 located at the lower end of the piezoelectric energy harvester starts to vibrate, and transmits the vibration force along the vertical direction to the V-shaped bent plate 31 of the force amplifier 27 through the elastic spring 28. Affected by the mechanical structure characteristics of the V-shaped bent plate 31, the vertical braking force is amplified into a horizontal vibration force and acts on the rectangular action plate 32. The piezoelectric ceramic material 26 deforms under the action of the force. Due to the different slopes of the arc curve segments of the piezoelectric ceramic material 26, this force is further amplified. At the same time, affected by the semi-periodic deformation of the piezoelectric ceramic material 26, the mass 25 makes an equivalent reciprocating movement along the sliding rod 24. On the one hand, it prevents the piezoelectric ceramic material 26 from breaking due to overload vibration force. On the other hand, the reciprocating movement of the mass 25 drives the reciprocating deformation of the piezoelectric ceramic material 26 in turn;

[0037] The piezoelectrically converted electrical energy is first input into the power controller 20 for intensity analysis to obtain the intensity data of the real-time external environment damping influence of the airframe 6, so as to feedback-regulate the output power of the drone motor and the airframe attitude to improve the operation stability of the airframe and reduce unnecessary damping resistance losses; at the same time, the piezoelectrically converted electrical energy is stored in the lithium battery 15 through the first DC-DC converter 17; since the piezoelectric ceramic material 26 is of a bistable design, it can improve the collection ability of the piezoelectric energy harvester at different resonance frequencies, especially improve the energy conversion efficiency in low-frequency vibrations. In addition, the bistable design can also reduce the fatigue damage problem caused by stress concentration of the piezoelectric ceramic material 26 during the long-endurance operation of the drone;

[0038] The mass 25 is set as a coil motor, and the lower end of the sliding rod 24 is set as a magnetic shaft. Through the reciprocating linear motion of the mass 25 at the lower end of the sliding rod 24, the coil motor continuously cuts the magnetic field to generate DC electrical energy, and the DC electrical energy is stored in the lithium battery 15 through the first DC-DC converter 17.

[0039] Refer to Figure 4, when an unmanned aerial vehicle (UAV) hydrogen-electric hybrid power system performs energy conversion, the low-voltage electric energy generated by the hydrogen fuel cell 13 is transmitted to the bus module 18 after passing through the second DC-DC converter 35, and the low-voltage electric energy in the lithium battery 15, the piezoelectric energy harvester, and the linear reciprocating electromagnetic generator is transmitted to the bus module 18 after passing through the first DC-DC converter 17; on the one hand, the bus module 18 transmits the obtained electric energy to the power supply controller 20 in the energy management system 36 after passing through the DC-AC converter 19, and the power supply controller 20 is used to uniformly call and transmit the electric energy to the power-consuming components in the airframe 6. On the other hand, the bus module 18 can step down a part of the electric energy from the hydrogen fuel cell 13, the piezoelectric energy harvester, and the linear reciprocating electromagnetic generator through the first DC-DC converter 17 and store it in the lithium battery 15.

[0040] Refer to Figure 5 , an energy management method for an unmanned aerial vehicle hydrogen-electric hybrid power system, including:

[0041] After the UAV is ready for takeoff and completes the system self-check, the system evaluates and judges the current state of the hydrogen fuel cell 13. If the state of the hydrogen fuel cell 13 is normal, start the hydrogen fuel cell 13 and preheat it. Otherwise, alarm and terminate the process; during the takeoff stage of the UAV, the lithium battery 15 supplies power instantaneously, and then judges the current takeoff height of the UAV. If the takeoff height reaches the threshold, the energy management system switches to the hydrogen fuel cell 13 for continuous power supply. Otherwise, continue to use the lithium battery 15 as the main power supply; when the hydrogen fuel cell 13 supplies power continuously, the UAV ends the initial takeoff stage and triggers a normal power supply demand, and then judges whether there is a high-power demand at this stage. If so, introduce the lithium battery 15 as the main power supply device and evaluate the remaining power of the lithium battery 15. If the remaining power of the lithium battery 15 is lower than the threshold, request the system to intervene in the hydrogen fuel cell 13 for main power supply. If the system response fails, alarm and terminate the process. If there is no high-power demand at this stage, continue to use the hydrogen fuel cell 13 as the power supply device;

[0042] When the hydrogen fuel cell 13 supplies main power, the system evaluates the output status of the hydrogen fuel cell 13 in real time. If the output state of the hydrogen fuel cell 13 is stable, switch to the hybrid power supply mode. In the hybrid power supply mode, the UAV adopts a power supply mode mainly powered by the hydrogen fuel cell 13 and supplemented by the lithium battery 15. Otherwise, if it is unstable, alarm and take a forced landing treatment;

[0043] In the described hybrid power supply mode, the energy management system 36 intervenes. Due to the vibration generated by the maneuver of the drone, the resonant mass block 29 of the mechanical resonator in the water tank 14 begins to move up and down reciprocally, thereby prompting the piezoelectric energy harvester and the electromagnetic generator to convert the vibration energy. Since the converted electric energy of the piezoelectric energy harvester is positively correlated with the current vibration amplitude of the drone, the converted electric energy output by the piezoelectric energy harvester is first judged against a threshold. If the converted electric energy exceeds the threshold, it indicates that the damping effect of the current external environment of the fuselage is relatively large and there is a high-power power supply demand at this stage. Then, the energy management system 36 adjusts the power supply strategy. At the same time, the electric energy converted by the piezoelectric energy harvester and the electromagnetic generator is sent to the lithium battery 15 for storage after passing through the first DC-DC converter 17.

[0044] The above content is a further detailed description of the present invention in combination with specific preferred implementation manners. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A hydrogen-electric hybrid power system for an unmanned aerial vehicle, comprising a body (6), characterized in that: A hydrogen fuel cell system (33), a power battery system (34) and an energy management system (36) are arranged in the body (6); the electric energy output by the hydrogen fuel cell system (33) and the power battery system (34) is supplied to the electric motor (21) via the energy management system (36); the electric motor (21) controls the propeller blade (1); the rotation speed of the electric motor (21) is independently adjusted, and the attitude and movement of the UAV are controlled by changing the direction and magnitude of the lift.

2. The hydrogen-electric hybrid power system of a drone according to claim 1, characterized in that: The hydrogen fuel cell system (33) comprises a hydrogen storage tank (7), the inlet end of the hydrogen storage tank (7) is connected to the hydrogen injection port (5) located on the body (6) through a fluid pipeline, the outlet end of the hydrogen storage tank (7) is connected to the hydrogen inlet of the humidifier (9) through a switch valve (10), and the hydrogen outlet of the humidifier (9) is connected to the hydrogen fuel cell (13); the gas storage bottle (8) is connected to the air inlet of the humidifier (9) through an air output pipeline, and the air outlet of the humidifier (9) is connected to the hydrogen fuel cell (13), and hydrogen and air are burned in the hydrogen fuel cell (13).

3. The hydrogen-electric hybrid power system of a drone according to claim 2, characterized in that: The power battery system (34) comprises a lithium battery (15), the lithium battery (15) is an all-weather high-rate lithium battery, the lithium battery (15) is connected to the bus module (18) via a first DC-DC converter (17), the hydrogen fuel cell (13) is connected to the bus module (18) via a second DC-DC converter (35), the low-voltage current generated by the hydrogen fuel cell (13) is upgraded to a high-voltage input bus module (18) via the second DC-DC converter (35), on the one hand, the first DC-DC converter (17) converts the low-voltage current generated by the lithium battery (15) into a high-voltage current. The low voltage current of the battery (15) is boosted to be input into the bus module (18). On the other hand, the first DC-DC converter (17) steps down the high voltage current from the bus module (18) to be input into the lithium battery (15) for storage. The bus module (18) converts the DC power into AC power via the DC-AC converter (19) and transmits the AC power to the power controller (20) in the energy management system (36). The power controller (20) transmits the electric energy to other power-consuming modules inside the machine body (6), including the water pump (12) and the motor (21).

4. The hydrogen-electric hybrid power system of a drone according to claim 3, characterized in that: The energy management system (36) comprises a heat dissipation energy management system and an energy collection system; the heat dissipation energy management system comprises a passive air-cooling heat dissipation structure and an active heat dissipation system; the passive air-cooling heat dissipation structure is located on the body (6) on the side close to the hydrogen fuel cell (13), the heat sink is designed as a stacked fin structure, the material is an aluminum alloy, and the fins are stacked and fixed after being stamped; the active heat dissipation system comprises a heat exchanger (11), the heat exchanger (11) exchanges heat with the hydrogen fuel cell (13) through a cooling pipeline, the heat exchanger (11) is connected to a water tank (14) through a water pump (12), and the water tank (14) is arranged in the body (6); an installation groove is arranged on the side close to the hydrogen fuel cell (13) in the body (6), and the cooling pipeline is laid in the installation groove; secondly, a control device and a temperature sensor are also arranged on the side close to the hydrogen fuel cell (13) in the body (6), the number of temperature sensors is the same as the number of battery stacks in the hydrogen fuel cell (13), and each temperature sensor corresponds to a battery stack in a hydrogen fuel cell (13).

5. The hydrogen-electric hybrid power system of a drone according to claim 4, characterized in that: The energy harvesting system comprises an energy harvester disposed inside the water tank (14), the energy harvester being connected to a power supply controller (20); the energy harvester comprising a piezoelectric energy harvester, a mechanical resonator and a linear reciprocating electromagnetic generator; the piezoelectric energy harvester comprising a support plate (22), the upper portion of the support plate (22) being connected to the top of the water tank (14), the lower portion of the support plate (22) being vertically connected to the upper end of a connecting rod (23), the upper portion of the connecting rod (23) being connected to a force amplifier (27), and the force amplifier The device (27) comprises two V-shaped bent plates (31) arranged horizontally in the upper and lower parts and two rectangular action plates (32) connected thereto and arranged vertically in the left and right parts. The V-shaped bent plates (31) are provided with a sliding rod (24) in the vertical direction of the angle bisector. The sliding rod (24) is connected to a mass block (25). The mass block (25) and the sliding rod (24) form a moving pair. In the horizontal direction, one end of the piezoelectric ceramic material (26) is connected to the mass block (25), and the other end is connected to the rectangular action plate (32). The mechanical resonator comprises an elastic spring (28) and a resonant mass block (29); a V-shaped bent plate (31) located at the lower side of the force amplifier (27) is connected to the resonant mass block (29) through the elastic spring (28); and a limiter (30) is arranged at a port of the connecting rod (23) close to one side of the resonant mass block (29); The resonant mass block (29) is configured as a coil motor, the lower end of the connecting rod (23) is a magnetic axis formed by like magnetic poles approaching each other, and the magnetic axis at the lower end of the connecting rod (23), the elastic spring (28) and the resonant mass block (29) together constitute a linear reciprocating electromagnetic generator.

6. The hydrogen-electric hybrid power system of a drone according to claim 5, characterized in that: The piezoelectric ceramic material (26) is in the shape of an irregular arc, and the curvature of the curve gradually increases along the direction from the rectangular action plate (32) to the mass block (25). The piezoelectric ceramic material (26) is a bistable design, and there is a piezoelectric ceramic material (26) on each side of the mass block (25), and the two are mirror-symmetrical.

7. The energy management method of a hydrogen-electric hybrid power system of a UAV according to any one of claims 5-6, characterized in that: After the drone is ready for takeoff and completes the system self-check, if the hydrogen fuel cell (13) is in normal condition, the hydrogen fuel cell (13) is started and preheated, otherwise an alarm is sounded and the process is terminated; during the drone takeoff phase, the lithium battery (15) instantly supplies power, and then the current takeoff altitude of the drone is judged. If the takeoff altitude reaches a threshold, the energy management system switches to the hydrogen fuel cell (13) for continuous power supply, otherwise the lithium battery (15) continues to be used as the main power supply; when the hydrogen fuel cell (13) is continuously supplying power, the drone ends the initial takeoff phase and triggers a normal power supply demand, and then a judgment is made as to whether there is a high power demand at the current stage. If so, the lithium battery (15) is introduced as the main power supply device and the lithium battery (15) is switched to the main power supply device. The remaining power of the battery (15) is evaluated. If the remaining power of the lithium battery (15) is lower than a threshold value, the system is requested to intervene in the hydrogen fuel cell (13) for main power supply. If the system responds to a fault, an alarm is issued and the process is terminated. If there is no high power demand at this stage, the hydrogen fuel cell (13) continues to be used as the power supply device. When the hydrogen fuel cell (13) is the main power supply, the system evaluates the output status of the hydrogen fuel cell (13) in real time. If the output status of the hydrogen fuel cell (13) is stable, it switches to a hybrid power supply mode. In the hybrid power supply mode, the drone adopts a power supply mode in which the hydrogen fuel cell (13) is the main power supply and the lithium battery (15) is the auxiliary power supply. Otherwise, if it is unstable, an alarm is issued and forced landing is taken.

8. The energy management method according to claim 7, characterized in that: In the hybrid power supply mode, the energy management system (36) intervenes and first performs a threshold judgment on the converted electric energy output by the piezoelectric energy harvester. If the converted electric energy exceeds the threshold, it indicates that the damping effect of the external environment of the current body is large and there is a high-power power supply demand at this stage. The power supply strategy is adjusted through the energy management system (36); at the same time, the electric energy converted by the piezoelectric energy harvester and the linear reciprocating electromagnetic generator is transmitted to the lithium battery (15) for storage after passing through the first DC-DC converter (17).

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