Hybrid lift and thrust system for low-altitude vertical take-off and landing aircraft and operation method of hybrid lift and thrust system

Abstract

The invention belongs to the technical field of aviation power systems, and discloses an operation method of a hybrid lift and thrust system machine for a low-altitude vertical take-off and landing aircraft, and the system comprises a low-pressure compressor, a generator / generator, a high-pressure compressor, a gas turbine, an adjustable thrust nozzle, a PEM fuel cell, a motor and a lift propeller, the low-pressure air compressor, the starting / power generator, the high-pressure air compressor and the gas turbine are of a coaxial structure, air compressed by the low-pressure air compressor is divided into two paths, one path of compressed air enters the high-pressure air compressor to be further pressurized and then enters the main combustion chamber, and the rear end of the main combustion chamber is connected with the gas turbine; the other path of compressed air of the low-pressure compressor respectively enters a cathode inlet of the PEM fuel cell and an adjustable thrust spray pipe; the PEM fuel cell supplies power to the electric bus bar, and the reaction rear end of the PEM fuel cell is connected with the mixer; an exhaust port of the gas turbine is connected with a mixer, and the mixer mixes tail gas of the gas turbine and tail gas of the PEM fuel cell and then provides the mixed tail gas to an adjustable thrust spray pipe at the rear end to provide thrust; the starter / generator is connected with an electric bus bar which is connected with a motor, and a rotating shaft of the motor drives a lift propeller. The system can be used for manned aerial vehicles and unmanned aerial vehicles adopting rotor wing take-off and landing and thrust cruising, the using number of rotating shafts is reduced, the system structure is simplified, the requirement for H2 is reduced, and the system working time is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of aviation power systems, and relates to a hybrid lift and thrust system for a low-altitude vertical take-off and landing aircraft, and specifically relates to a hybrid lift and thrust system for a low-altitude vertical take-off and landing aircraft. Background Art

[0002] With the introduction of the low-altitude economy, low-altitude manned / unmanned aircraft have developed rapidly. At present, most of these aircraft adopt the technical route of power battery power supply, and provide lift through electric motors to drive lift propellers. Limited by the energy density of power batteries, current battery-powered low-altitude aircraft are difficult to sustain for a long time, which restricts the development of low-altitude manned / unmanned aircraft. This patent proposes a hybrid lift and thrust system combining a PEM fuel cell and a gas turbine to replace the current power battery power system. The jet thrust of the gas turbine can provide propulsion for the flight of the aircraft, and the electric energy generated by the gas turbine and the fuel cell drives the lift propeller through the electric motor to provide lift. The present invention provides a new technical solution for long-flight aircraft. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a hybrid lift and thrust system for low-altitude vertical take-off and landing aircraft and an operating method thereof, which has the function of providing lift and thrust at the same time, is flexible to adjust, and has the characteristics of long flight time. The present invention can provide multi-electric long-flight hybrid power technology for low-altitude economical aircraft.

[0004] The technical solution of the present invention is as follows:

[0005] A hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft comprises a low pressure compressor, a starter / generator, a high pressure compressor, a gas turbine, an adjustable thrust nozzle, a PEM fuel cell, an electric motor, and a lift propeller. The low pressure compressor, the starter / generator, the high pressure compressor and the gas turbine are coaxial structures. The air compressed by the low pressure compressor is divided into two paths. One path of compressed air enters the high pressure compressor for further pressurization and then enters the main combustion chamber, and the rear end of the main combustion chamber is connected to the gas turbine; the other path of compressed air from the low pressure compressor enters the cathode inlet and the adjustable thrust nozzle of the PEM fuel cell respectively; the PEM fuel cell supplies power to the electric bus bar, and the reaction rear end of the PEM fuel cell is connected to a mixer; the exhaust port of the gas turbine is connected to the mixer, and the mixer mixes the exhaust gas of the gas turbine and the exhaust gas after the PEM fuel cell, and then provides it to the adjustable thrust nozzle at the rear end to provide thrust; the starter / generator is connected to the electric bus bar, and the electric bus bar is connected to the electric motor, and the rotating shaft of the electric motor drives the lift propeller.

[0006] Furthermore, it also includes a secondary combustion chamber, which is arranged at the reaction rear end of the PEM fuel cell. The incompletely reacted combustible gas and oxygen in the PEM fuel cell are further burned in the secondary combustion chamber, and the further burned fuel gas then enters the mixer.

[0007] Furthermore, it also includes an H2 fuel tank and a fuel tank, the fuel tank is connected to the main combustion chamber, and the H2 fuel tank is connected to the anode inlet of the PEM fuel cell.

[0008] Furthermore, it also includes a system controller and a starter, the starter is powered by an electrical bus and connected to a starter / generator; the system controller connects and controls the starter, the starter / generator, the PEM fuel cell and the thrust regulating valve, and the thrust regulating valve is arranged on the branch line from the low-pressure compressor to the adjustable thrust nozzle.

[0009] Furthermore, it also includes a DC / DC power conversion unit and an AC / DC power conversion unit. The generator supplies power to the electric bus through the AC / DC power conversion unit, and the PEM fuel cell supplies power to the electric bus through the DC / DC power conversion unit.

[0010] Furthermore, it also includes a water cooling circuit, a heat exchanger and a coolant cooling circuit. The water cooling circuit is divided into two water circuits after passing through the cold end of the heat exchanger: one water circuit is mixed with the compressed air entering the cathode of the PEM fuel cell into humid air; the other water circuit exchanges heat with the PEM fuel cell as a whole, and then sprays into the main combustion chamber; the coolant cooling circuit passes through the hot end of the heat exchanger, exchanges heat with the system controller, starter, DC / DC power conversion unit and AC / DC power conversion unit respectively, and then enters the hot end circulation of the heat exchanger.

[0011] Furthermore, it also includes a secondary exhaust valve, which is connected and controlled by the system control system. The secondary exhaust valve is arranged at the rear end of the secondary combustion chamber, and the other end of the secondary exhaust valve is connected to the outside.

[0012] A method for operating a hybrid lift and thrust system for a low-altitude vertical take-off and landing aircraft, using the aforementioned hybrid lift and thrust system for a low-altitude vertical take-off and landing aircraft, includes the following methods:

[0013] The working mode is switched according to the aircraft status and system working requirements. High-power energy is required during the aircraft takeoff. The power extraction of the gas turbine engine is adjusted by controlling the starter / generator, and the thrust of the adjustable thrust nozzle is reduced to zero. The PEM fuel cells work at the same time, and the power distribution system distributes electric motor power to drive the lift propeller to provide takeoff lift. After the aircraft enters the cruise phase, the energy extraction of the starter / generator is controlled to be reduced, and the gas turbine exhaust provides thrust through the adjustable thrust nozzle.

[0014] Furthermore, the control of the generator at different flight altitudes of the aircraft can achieve the rotation speed regulation of the low-pressure compressor, thereby regulating the high-pressure air flow entering the cathode of the PEM fuel cell to be stable.

[0015] Furthermore, the generator is controlled to operate at a low speed to save energy when the aircraft is on the ground; when the aircraft is at high altitude, the system controller controls the generator to operate at a high speed and opens the water cooling circuit to assist with water cooling and humidification to maintain the working environment temperature of the PEM fuel cell at low and high altitudes.

[0016] Advantages of the present invention:

[0017] 1. The present invention provides a hybrid lift and thrust system used by low-altitude vertical take-off and landing aircraft, which can be used for manned aircraft and unmanned aircraft that adopt rotor take-off and landing and thrust cruising.

[0018] 2. The present invention reduces the number of rotating shafts used by installing the low-pressure compressor, high-pressure compressor, gas turbine, and generator on the same shaft, eliminating the traditional gear reduction transmission device, thereby greatly simplifying the system structure.

[0019] 3. The main combustion chamber of the present invention can accept portable fuels such as kerosene, and is designed with a water spray structure, which uses water cooling to convert into steam, thereby avoiding performance degradation caused by the use of cooling air and reducing pollutant emissions.

[0020] 4. The present invention designs a fuel cell power generation unit consisting of an H2 fuel tank, a PEM fuel cell, and a secondary combustion chamber. The PEM fuel cell receives high-temperature compressed gas from a low-pressure compressor. The high-temperature and high-pressure gas from the compressor can be used to perform hot air purge on the cold start of the fuel cell, helping the PEM fuel cell solve the problem of low-temperature start. At the same time, the high-temperature and high-pressure air at the compressor outlet is humidified and cooled by liquid water cooling, simplifying the requirements for system accessories.

[0021] 5. The present invention adopts a dual-fuel concept. The PEM fuel cell uses high-purity hydrogen provided by an H2 tank, and the combustion engine unit uses portable fuel provided by a fuel tank. On the one hand, it solves the problem that H2 is difficult to carry on aircraft to a certain extent, that is, it reduces the demand for H2. On the other hand, the fuel tank carries portable fuels such as kerosene to increase the working time of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the implementation method of the patent of the present invention, the following is a brief introduction to the drawings required for use in the implementation method. It should be understood that the following drawings only show certain embodiments of the patent of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a structural schematic diagram of a dual-fuel aircraft combined power system of the present invention;

[0024] Among them, 1- low-pressure compressor, 2- starter / generator, 3- high-pressure compressor, 4- main combustion chamber, 5- fuel tank, 6- gas turbine, 7- mixer, 8- adjustable thrust nozzle, 9- secondary combustion chamber, 10- PEM fuel cell, 11- H2 fuel tank, 12- pump, 13- heat exchanger, 14- battery, 15- motor, 16- lift propeller, 17- power distribution system, 18- electrical bus, 19- DC / DC power conversion unit, 20- AC / DC power conversion unit, 21- system controller, 22- starter. DETAILED DESCRIPTION

[0025] This section is an embodiment of the present invention, which is used to explain and illustrate the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships as given in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or case referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be interpreted in a broad sense, for example, it can be a fixed connection, a detachable connection or an integrated connection; it can be a mechanical connection or a point connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0028] Embodiment 1:

[0029] A hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft, comprising a low pressure compressor 1, a starter / generator 2, a high pressure compressor 3, a gas turbine 6, an adjustable thrust nozzle 8, a PEM fuel cell 10, an electric motor 15, and a lift propeller 16. The low pressure compressor 1, the starter / generator 2, the high pressure compressor 3, and the gas turbine 6 are coaxial structures. The air compressed by the low pressure compressor 1 is divided into two paths. One path of compressed air enters the high pressure compressor 3 for further pressurization and then enters the main combustion chamber 4. The rear end of the main combustion chamber 4 is connected to the gas turbine 5. The low pressure compressor 1 is connected to the high pressure compressor 3. Another path of compressed air enters the cathode inlet of the PEM fuel cell 7 and the adjustable thrust nozzle 8 respectively; the PEM fuel cell 7 supplies power to the electric bus bar, and the reaction rear end of the PEM fuel cell 7 is connected to the mixer 7; the exhaust port of the gas turbine 5 is connected to the mixer 7, and the mixer 7 mixes the exhaust gas of the gas turbine 5 and the exhaust gas after the PEM fuel cell 7, and provides it to the adjustable thrust nozzle 8 at the rear end to provide thrust; the generator 2 is connected to the electric bus bar 18, and the electric bus bar 18 is connected to the electric motor 15, and the rotating shaft of the electric motor 15 drives the lift propeller 16.

[0030] It also includes a secondary combustion chamber 9, which is arranged at the reaction rear end of the PEM fuel cell 7. The incompletely reacted combustible gas and oxygen in the PEM fuel cell 7 are further burned in the secondary combustion chamber 9, and the further burned fuel gas then enters the mixer 7.

[0031] It also includes an H2 fuel tank 11 and a fuel tank 5 , wherein the fuel tank 5 is connected to the main combustion chamber 4 , and the H2 fuel tank 11 is connected to the anode inlet of the PEM fuel cell 7 .

[0032] It also includes a system controller 21 and a starter 22. The starter 22 is powered by the electrical bus 18 and is connected to the starter / generator 2. The system controller 21 connects and controls the starter 22, the starter / generator 2, the PEM fuel cell 7 and the thrust regulating valve. The thrust regulating valve is arranged on the branch of the low-pressure compressor 1 to the adjustable thrust nozzle 8.

[0033] It also includes a DC / DC power conversion unit 19 and an AC / DC power conversion unit 20 . The generator 2 supplies power to the electric bus 18 via the AC / DC power conversion unit 20 , and the PEM fuel cell 7 supplies power to the electric bus 18 via the DC / DC power conversion unit 19 .

[0034] It also includes a water cooling circuit, a heat exchanger 13 and a coolant cooling circuit. The water cooling circuit is divided into two water circuits after passing through the cold end of the heat exchanger 13: one water circuit is mixed with the compressed air entering the cathode of the PEM fuel cell 10 to form humid air; the other water circuit exchanges heat for the PEM fuel cell 10 as a whole, and then sprays into the main combustion chamber 4; the coolant cooling circuit exchanges heat for the system controller 21, the starter 22, the DC / DC power conversion unit 19 and the AC / DC power conversion unit 20 respectively after passing through the hot end of the heat exchanger 13.

[0035] It also includes a secondary exhaust valve, which is connected and controlled by the system control system 21. The secondary exhaust valve is arranged at the rear end of the secondary combustion chamber 9, and the other end of the secondary exhaust valve is connected to the outside.

[0036] A method for operating a hybrid lift and thrust system for a low-altitude vertical take-off and landing aircraft, using the aforementioned hybrid lift and thrust system for a low-altitude vertical take-off and landing aircraft, includes the following methods:

[0037] The working mode is switched according to the aircraft status and system working requirements. High-power energy is required during the aircraft take-off. The power extraction of the gas turbine engine is adjusted by controlling the starter / generator 2, and the thrust of the adjustable thrust nozzle 8 is reduced to zero. The PEM fuel cell 7 works at the same time, the secondary exhaust valve is opened, and the power distribution system 17 distributes electricity from the electric motor 15 to drive the lift propeller 16 to provide take-off lift; after the aircraft enters the cruise phase, the energy extraction of the starter / generator 2 is controlled to be reduced and the secondary exhaust valve is closed, and the exhaust gas of the gas turbine 6 provides thrust through the adjustable thrust nozzle 8.

[0038] The control of the generator 2 at different flight altitudes of the aircraft realizes the rotation speed regulation of the low-pressure compressor 1, thereby regulating the high-pressure air flow entering the cathode of the PEM fuel cell 7 to be stable.

[0039] Embodiment 2:

[0040] A hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft and an operation method thereof, comprising a low pressure compressor 1, a starter / generator 2, a high pressure compressor 3, a gas turbine 6, an adjustable thrust nozzle 8, a PEM fuel cell 10, an electric motor 15, and a lift propeller 16. The low pressure compressor 1, the starter / generator 2, the high pressure compressor 3, and the gas turbine 6 are coaxial structures. The air compressed by the low pressure compressor 1 is divided into two paths. One path of compressed air enters the high pressure compressor 3 and then enters the main combustion chamber 4, and the rear end of the main combustion chamber 4 is connected to the gas turbine 5; the other path of compressed air enters the PEM fuel cell 7 and the adjustable thrust nozzle 8. The PEM fuel cell 7 supplies power to the electric bus bar, and the reaction rear end of the PEM fuel cell 7 is connected to the mixer 7; the mixer 7 is driven by the main combustion chamber 4 and the PEM fuel cell 7, and the exhaust channel of the gas turbine 5 passes through the adjustable thrust nozzle 8 to provide thrust.

[0041] The system further comprises a secondary combustion chamber 6 , which is arranged between the PEM fuel cell 7 and the gas turbine 5 , and the fuel and air which are not completely reacted in the PEM fuel cell 7 are burned in the secondary combustion chamber 6 .

[0042] It also includes an H2 fuel tank 8 and a fuel tank 3 , wherein the fuel tank 3 is connected to the main combustion chamber 4 , and the H2 fuel tank 8 is connected to the PEM fuel cell 7 .

[0043] It also includes a system controller 21 and a starter 22 . The starter 22 is powered by an electrical bus and connected to the starter / generator 2 . The system controller 21 connects and controls the starter 22 , the starter / generator 2 , the power distribution system 17 and the PEM fuel cell 7 .

[0044] It also includes a DC / DC power conversion unit 19 and an AC / DC power conversion unit 20 . The generator 2 supplies power to the electric bus 18 via the AC / DC power conversion unit 20 , and the PEM fuel cell 7 supplies power to the electric bus 18 via the DC / DC power conversion unit 19 .

[0045] The storage battery 14 and the power distribution system 17 distribute the power supplied from the power bus 18 and control the charging / discharging process of the storage battery and the power supply to the motor 15 .

[0046] It also includes a heat exchanger 13 and a pump 12. The water cooling circuit cools the heat exchanger 13 and the PEM fuel cell 7 before and after. The DC / DC power conversion unit 19, the AC / DC power conversion unit 20, the system controller 21, and the starter 22 are cooled by a coolant medium. The coolant is driven by the pump 12 and connected to the cold end of the heat exchanger 13.

[0047] The main combustion chamber 4 is water-cooled, and water-spray cooling combustion can effectively reduce pollutant emissions.

[0048] A method for operating a hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft, comprising the following method:

[0049] The system controller 21 switches the working mode according to the aircraft status and system working requirements. During takeoff, high-power energy is required. The power extraction of the gas turbine engine is adjusted by controlling the starter / generator 2, and the thrust of the adjustable thrust nozzle 8 is reduced to zero. The PEM fuel cell 7 works at the same time, the secondary exhaust valve is opened, and the power distribution system 17 distributes the power of the motor 15 to drive the lift propeller 16 to provide takeoff lift. During the cruise phase, the system controller 21 controls the reduction of the energy extraction of the starter / generator 2 and closes the secondary exhaust valve. The exhaust gas of the gas turbine 6 provides thrust through the adjustable thrust nozzle 8.

[0050] The system controller 21 adjusts the speed of the air compressor 1 by controlling the generator 2, thereby adjusting the high-pressure air entering the cathode of the PEM fuel cell 7 and stabilizing the working conditions of the fuel cell.

[0051] The system controller 21 controls the generator / generator 2. When the aircraft is on the ground, the generator / generator 2 is controlled to operate at a low speed to save energy, that is, below 60% of the rated speed. When the aircraft is at a high altitude, the system controller 21 controls the generator / generator 2 to operate at a high speed, that is, above 90% of the rated speed, and at the same time opens the water cooling circuit to assist with water cooling and humidification to maintain the working environment temperature of the PEM fuel cell 7 at low and high altitudes.

[0052] The above is only a specific embodiment of the present invention, and the present invention is described in detail. The unexplained part is a conventional technology. However, the protection scope of the present invention is not limited to this. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft, characterized in that: The invention comprises a low-pressure compressor (1), a generator (2), a high-pressure compressor (3), a gas turbine (6), an adjustable thrust nozzle (8), a PEM fuel cell (10), an electric motor (15), and a lift propeller (16). The low-pressure compressor (1), the generator (2), the high-pressure compressor (3), and the gas turbine (6) are coaxial structures. The air compressed by the low-pressure compressor (1) is divided into two paths. One path of the compressed air enters the high-pressure compressor (3) for further pressurization and then enters the main combustion chamber (4). The rear end of the main combustion chamber (4) is connected to the gas turbine (5); the other path of the compressed air of the low-pressure compressor (1) enters the P The cathode inlet of the PEM fuel cell (7) and the adjustable thrust nozzle (8); the PEM fuel cell (7) supplies power to the electric bus bar (18), and the reaction rear end of the PEM fuel cell (7) is connected to the mixer (7); the exhaust port of the gas turbine (5) is connected to the mixer (7), and the mixer (7) mixes the exhaust gas of the gas turbine (5) and the exhaust gas of the PEM fuel cell (7), and then provides the mixed exhaust gas to the adjustable thrust nozzle (8) at the rear end to provide thrust; the generator (2) is connected to the electric bus bar (18), and the electric bus bar (18) is connected to the electric motor (15), and the rotating shaft of the electric motor (15) drives the lift propeller (16).

2. The hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft according to claim 1, characterized in that: It also includes a secondary combustion chamber (9), which is arranged at the reaction rear end of the PEM fuel cell (7). The incompletely reacted combustible gas and oxygen in the PEM fuel cell (7) are further burned in the secondary combustion chamber (9), and the further burned fuel gas then enters the mixer (7).

3. The hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft according to claim 1, characterized in that: It also includes an H2 fuel tank (11) and a fuel tank (5), wherein the fuel tank (5) is connected to the main combustion chamber (4), and the H2 fuel tank (11) is connected to the anode inlet of the PEM fuel cell (7).

4. The hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft according to claim 1, characterized in that: The invention also includes a system controller (21) and a starter (22), wherein the starter (22) is powered by an electric bus bar (18) and connected to a starter / generator (2); the system controller (21) is connected to and controls the starter (22), the starter / generator (2), the PEM fuel cell (7) and a thrust regulating valve, wherein the thrust regulating valve is arranged on a branch of the low-pressure compressor (1) that diverts air to an adjustable thrust nozzle (8).

5. The hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft according to claim 1, characterized in that: It also includes a DC / DC power conversion unit (19) and an AC / DC power conversion unit (20), the generator (2) supplies power to the electric bus bar (18) through the AC / DC power conversion unit (20), and the PEM fuel cell (7) supplies power to the electric bus bar (18) through the DC / DC power conversion unit (19).

6. The hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft according to claim 5, characterized in that: The invention also comprises a water cooling circuit, a heat exchanger and a coolant cooling circuit. The water cooling circuit is divided into two water circuits after passing through the cold end of the heat exchanger (13): one water circuit is mixed with the compressed air entering the cathode of the PEM fuel cell (10) to form wet air; the other water circuit exchanges heat with the PEM fuel cell (10) as a whole and then sprays into the main combustion chamber (4); the coolant cooling circuit exchanges heat with the system controller (21), the starter (22), the DC / DC power conversion unit (19) and the AC / DC power conversion unit (20) respectively after passing through the hot end of the heat exchanger (13).

7. The hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft according to claim 1, characterized in that: It also includes a secondary discharge valve, which is connected and controlled by the system control system (21). The secondary discharge valve is arranged at the rear end of the secondary combustion chamber (9), and the other end of the secondary discharge valve is connected to the outside.

8. A method for operating a hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft, using a hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft as claimed in any one of claims 1 to 7, characterized in that: The following methods are included: The working mode is switched according to the aircraft status and system working requirements. High-power energy is required during the aircraft take-off process. The power extraction of the gas turbine engine is adjusted by controlling the starter / generator (2), and the thrust of the adjustable thrust nozzle (8) is reduced to zero. The PEM fuel cell (7) works at the same time, the secondary exhaust valve is emptied, and the power distribution system (17) distributes the electric motor (15) to drive the lift propeller (16) to provide take-off lift; after the aircraft enters the cruise phase, the energy extraction of the starter / generator (2) is controlled to be reduced and the secondary exhaust valve is closed, and the exhaust gas of the gas turbine (6) provides thrust through the adjustable thrust nozzle (8).

9. The method for operating a hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft according to claim 8, characterized in that: The control of the generator (2) at different flight altitudes of the aircraft realizes the rotation speed regulation of the low-pressure compressor (1), thereby regulating the high-pressure air flow entering the cathode of the PEM fuel cell (7) to be stable.

10. The method for operating a hybrid lift and thrust system for a low altitude vertical take-off and landing aircraft according to claim 9, characterized in that: The generator (2) is controlled to operate at a low speed to save energy when the aircraft is on the ground; when the aircraft is at a high altitude, the system controller (21) controls the generator (2) to operate at a high speed and opens a water cooling circuit to assist in cooling and humidification of water to maintain the working environment temperature of the PEM fuel cell (7) at low altitude and high altitude.

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