Electric turbineless flight backpack with hydrogen energy hybrid propulsion system and control method

Abstract

The utility model provides a kind of electric turbineless flight backpack of hydrogen energy hybrid propulsion system and control method, belong to aircraft propulsion field.Solve the problem of existing device power system complex structure, insufficient sustained output capacity.It includes: motor drives fan and compressor;Hydrogen fuel cell and lithium battery are powered to motor by converter and inverter;Fan exhaust is connected with compressor air inlet by fan-compressor air pipe, and compressor exhaust is connected with hydrogen fuel cell cathode by first gas supply channel, and is connected with combustion chamber air inlet by second gas supply channel;Hydrogen tank exhaust is connected with hydrogen fuel cell anode by hydrogen tank-hydrogen fuel cell air pipe, and is connected with combustion chamber hydrogen supply port by hydrogen tank-combustion chamber air pipe;Combustion chamber exhaust is connected with each nozzle by combustion chamber valve, and each nozzle is equipped with independent nozzle built-in flow valve and nozzle angle adjusting mechanism;Controller controls motor speed and each valve and nozzle angle according to flight handle instruction and sensor component parameter.It is used in emergency rescue field.

Description

Technical Field

[0001] This invention belongs to the field of aircraft propulsion technology, and in particular relates to an electric turbineless flying backpack that uses a hydrogen hybrid propulsion system. Background Technology

[0002] With the development of the low-altitude economy and personal mobile platforms, backpack-mounted flight devices are showing increasing application demands in fields such as emergency rescue, low-altitude inspection, special operations, and short-distance mobility. These devices typically need to possess a high thrust-to-weight ratio, rapid thrust response, flexible flight attitude control, and reliable long-duration endurance within limited structural volume and weight constraints. However, existing backpack-mounted flight devices often struggle to achieve a balance among these performance indicators, exhibiting various structural contradictions.

[0003] Currently, common backpack-mounted flight propulsion solutions can be mainly divided into three categories. The first category uses a micro turbojet engine as the power source. A micro turbojet engine compresses air through a turbine-driven compressor, mixes it with fuel, combusts it, and then discharges it through a nozzle to generate thrust, exhibiting a high thrust density. However, in this type of solution, the turbine operates under a high-temperature, high-speed rotational environment, which not only places extremely high demands on the temperature resistance of materials and processing precision but also makes the overall structure complex and manufacturing costs high. Furthermore, the presence of the turbine means that the compressor speed must be coupled with the operating state of the combustion chamber and turbine, making independent adjustment impossible. This leads to a significant decrease in compressor efficiency under non-design conditions, increasing unnecessary energy loss. In addition, micro turbojet engines are noisy, have high exhaust temperatures, and require short maintenance cycles, posing significant safety concerns and user experience obstacles in backpack-mounted applications that are close to the human body.

[0004] The second type of solution uses an electric ducted fan or electric propeller as the propulsion device. This type of solution uses lithium batteries as energy storage units, and the electric motor directly drives the fan or propeller to generate thrust. The structure is relatively simple, the control response is fast, and it avoids the safety hazards caused by high-temperature rotating parts. However, limited by the current energy density level of lithium batteries, the battery capacity of purely electric backpack-type flight devices decays rapidly under continuous high thrust output conditions, resulting in extremely limited flight time. Even with high-rate discharge lithium batteries, it is difficult to simultaneously meet the dual requirements of long endurance and high thrust. Moreover, the battery heats up severely during continuous high-power discharge, and the weight and volume of the cooling system further encroaches on the effective payload space. Therefore, the pure electric solution has always faced the constraint of the endurance bottleneck in its practical application.

[0005] The third approach attempts to incorporate hydrogen fuel cells into the power system of personal aircraft. Hydrogen fuel cells directly convert the chemical energy of hydrogen into electrical energy through an electrochemical reaction, exhibiting high power generation efficiency and energy conversion rate, theoretically capable of significantly extending the flight time of the aircraft. However, relying solely on hydrogen fuel cells for power also has significant limitations: the dynamic response speed of fuel cells is slow, making it difficult to provide peak power in a timely manner during transient conditions such as takeoff, hovering corrections, attitude adjustments, or sudden thrust changes, easily leading to power interruptions or response lags. Furthermore, the normal operation of hydrogen fuel cells requires stable cathode air supply conditions; however, providing sufficient and stable compressed air within the limited space of a backpack-type aircraft without adding additional compressor equipment is also a challenging engineering feat.

[0006] Against this technological backdrop, some researchers have proposed a hybrid power supply scheme combining hydrogen fuel cells and lithium batteries to balance continuous power supply and transient power compensation. Simultaneously, others have attempted to combine hydrogen fuel cells with small gas turbines or micro turbojet engines, using the gas turbine to supply compressed air to the fuel cell while utilizing the fuel cell's waste heat to preheat the combustion chamber inlet air. However, these solutions either retain the turbine structure, failing to overcome the mechanical complexity, speed coupling, and maintenance costs associated with turbines; or they suffer from low system integration, with gas supply, energy distribution, and thermal management between subsystems interfering with each other, making stable and reliable control difficult to achieve in the extremely compact platform of a backpack-type aircraft.

[0007] In summary, existing backpack-type flight systems still face the following unresolved technical challenges at the power system level: First, how to achieve efficient independent compressor drive without eliminating the turbine, so that the compressor speed is no longer constrained by the combustion chamber's operating state; second, how to coordinate the conflict between the stable cathode gas supply required by the hydrogen fuel cell and the variable flow gas supply required by the combustion chamber within the same gas supply framework; third, how to achieve independent adjustment and coordinated control of the two hydrogen consumption paths—electrochemical reaction power generation and combustion heating jet—with hydrogen as a unified fuel source; fourth, how to achieve precise adjustment of thrust magnitude, thrust distribution, and jet direction in a multi-nozzle layout to meet the attitude control requirements of the backpack-type flight platform in confined spaces; and fifth, how to possess effective safety protection and degradation control capabilities when the system experiences fault states such as hydrogen leakage, combustion overheating, or abnormal gas supply. Summary of the Invention

[0008] In view of this, the present invention aims to propose an electric turbineless flying backpack and control method using a hydrogen hybrid propulsion system, in order to solve the problems of complex power system structure, insufficient continuous output capability, limited transient thrust response, and inflexible attitude adjustment of existing backpack flying devices.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: an electric turbineless flying backpack employing a hydrogen hybrid propulsion system, the flying backpack comprising: The enclosure, and the electric motor, DC / DC converter and inverter, lithium battery, hydrogen fuel cell, hydrogen storage tank, fan, compressor, first air supply channel, second air supply channel, combustion chamber, combustion chamber valve, first nozzle, second nozzle, third nozzle, fourth nozzle, first air supply channel valve, second air supply channel valve, first hydrogen branch valve, second hydrogen branch valve, flight handle, sensor assembly and controller mounted on the enclosure; The electric motor is connected to the fan and the compressor respectively, and the compressor is driven by the electric motor and has no gas turbine mechanical transmission path; The hydrogen fuel cell and lithium battery are electrically connected to the electric motor via a DC / DC converter and an inverter, respectively, forming a hybrid power supply circuit. The fan outlet is connected to the compressor inlet via a fan-compressor air supply line. The compressor outlet is connected to the hydrogen fuel cell cathode inlet and the combustion chamber air inlet via a first air supply channel and a second air supply channel, respectively. The first air supply channel is equipped with a first air supply channel valve, and the second air supply channel is equipped with a second air supply channel valve. The outlet of the hydrogen storage tank is connected to the anode inlet of the hydrogen fuel cell and the hydrogen supply port of the combustion chamber through the hydrogen storage tank-hydrogen fuel cell ventilation pipeline and the hydrogen storage tank-combustion chamber ventilation pipeline, respectively. The hydrogen storage tank-hydrogen fuel cell ventilation pipeline is equipped with a first hydrogen branch valve and the hydrogen storage tank-combustion chamber ventilation pipeline is equipped with a second hydrogen branch valve. The combustion chamber is equipped with a single combustion chamber. The combustion chamber outlet is connected to the inlet of the first nozzle, the second nozzle, the third nozzle and the fourth nozzle respectively through the combustion chamber valve. Each nozzle is equipped with an independent nozzle built-in flow valve and an independent nozzle angle adjustment mechanism. The flight handle is used to input flight commands to the controller, and the sensor assembly is used to collect the operating parameters of the electric motor, compressor, hydrogen fuel cell, lithium battery, combustion chamber, nozzles and pipelines and transmit them to the controller. The controller controls the motor speed, the first air supply channel valve, the second air supply channel valve, the first hydrogen branch valve, the second hydrogen branch valve, the combustion chamber valve, the built-in flow valve of each nozzle, and the nozzle angle adjustment mechanism according to the flight handle command and sensor component parameters.

[0010] Furthermore, a preferred embodiment is proposed, in which the hybrid power supply circuit supplies power to the motor via a hydrogen fuel cell through a DC / DC converter and an inverter, and the lithium battery supplies power to the motor via the same or parallel DC / DC converter and inverter; the controller allocates the output power of the hydrogen fuel cell and the lithium battery according to the flight status, wherein the hydrogen fuel cell is the main power source during stable flight, and the lithium battery is controlled to supplement the power supply to the motor during takeoff, acceleration, attitude adjustment or thrust change, and the lithium battery is charged via the DC / DC converter and inverter when the hydrogen fuel cell output is in surplus.

[0011] Furthermore, a preferred embodiment is proposed, wherein the fan and compressor are coaxial and connected to the same motor via a coupling or gear transmission; in the fan-compressor air supply pipeline, the fan outlet is set before the compressor inlet, and external air enters the first air supply channel and the second air supply channel after being pressurized by the fan and compressed by the compressor in sequence; the controller adjusts the opening of the valves of the first air supply channel and the second air supply channel according to the air demand of the hydrogen fuel cell cathode and the air demand of the combustion chamber, respectively.

[0012] Furthermore, a preferred embodiment is proposed, wherein the hydrogen storage tank-hydrogen fuel cell venting pipeline supplies reactive hydrogen to the anode of the hydrogen fuel cell, and the hydrogen storage tank-combustion chamber venting pipeline supplies combustion hydrogen to the combustion chamber; the controller adjusts the valve of the first hydrogen branch according to the hydrogen demand of the hydrogen fuel cell anode, and adjusts the valve of the second hydrogen branch according to the combustion equivalent and target heat load of the combustion chamber, and the hydrogen flow distribution of the hydrogen storage tank-hydrogen fuel cell venting pipeline and the hydrogen storage tank-combustion chamber venting pipeline is performed independently of the compressor air distribution.

[0013] Furthermore, a preferred embodiment is proposed in which the first nozzle, second nozzle, third nozzle, and fourth nozzle are distributed on the rear or periphery of the housing; each nozzle has a built-in flow valve that independently controls the flow rate of the high-temperature gas obtained from the combustion chamber valve; each nozzle angle adjustment mechanism independently controls the swing of the corresponding nozzle around the mounting axis; the controller adjusts the longitudinal thrust difference, lateral thrust difference, and yaw differential thrust respectively through the combination of the built-in flow valves and nozzle angle adjustment mechanisms of each nozzle.

[0014] Furthermore, a preferred embodiment is proposed, wherein the sensor assembly includes a motor speed sensor, a compressor outlet pressure sensor, a gas supply channel flow sensor, a hydrogen pressure sensor, a hydrogen flow sensor, a combustion chamber temperature sensor, a nozzle flow sensor, a nozzle angle sensor, a hydrogen fuel cell output status sensor, a lithium battery charge sensor, and a housing temperature sensor; the controller adjusts the motor speed, the first gas supply channel valve, the second gas supply channel valve, the first hydrogen branch valve, the second hydrogen branch valve, the combustion chamber valve, the built-in flow valve of each nozzle, and the angle of each nozzle based on the sensor parameters in a closed loop.

[0015] Furthermore, a preferred method is proposed whereby, when the sensor assembly outputs abnormal hydrogen pressure, abnormal hydrogen flow, combustion chamber temperature exceeding the preset range, abnormal nozzle flow, abnormal nozzle angle, abnormal hydrogen fuel cell output, abnormal lithium battery charge, or abnormal housing temperature, the controller performs the following protective control actions: reducing the motor speed, reducing or closing the first hydrogen branch valve and / or the second hydrogen branch valve, closing the combustion chamber valve, limiting the opening of the built-in flow valves of each nozzle, and adjusting the angle of each nozzle to a predetermined landing posture.

[0016] Furthermore, a preferred embodiment is proposed, wherein the enclosure is made of flame-retardant material and has an explosion-proof structure; the outer surface of the hydrogen storage tank, the hydrogen storage tank-hydrogen fuel cell ventilation pipeline, the hydrogen storage tank-combustion chamber ventilation pipeline, the outer wall of the combustion chamber, the pipelines from the combustion chamber valves to each nozzle, and the outer wall of each nozzle are all provided with heat insulation layers; a seat and safety belt are provided on the side of the enclosure closest to the human body, and wings are provided on both sides of the enclosure, which independently provide auxiliary lift or attitude stabilization with the nozzle thrust control.

[0017] Furthermore, a preferred embodiment is proposed, wherein the DC / DC converter and inverter include a DC / DC converter and an inverter, the hydrogen fuel cell and the lithium battery are connected to the DC bus via their respective or common DC / DC converters, and then the inverter supplies power to the motor; the controller jointly regulates the DC bus voltage, the hydrogen fuel cell output current, the lithium battery charging and discharging current and the three-phase current of the motor to match the power requirements of the compressor, fan and nozzle under variable thrust conditions.

[0018] Based on the same inventive concept, this invention also proposes a control method for an electric turbineless flying backpack employing a hydrogen hybrid propulsion system, comprising: It acquires the target flight command issued by the flight handle and the parameters of the electric motor, compressor, hydrogen fuel cell, lithium battery, combustion chamber, nozzles and pipelines collected by the sensor components; Determine the target's total thrust and target attitude based on the target's flight commands and parameters; Adjust the motor speed according to the target total thrust, and adjust the first air supply channel valve, the second air supply channel valve, the first hydrogen branch valve, the second hydrogen branch valve and the combustion chamber valve respectively, so that the compressor distributes compressed air to the hydrogen fuel cell cathode and combustion chamber, and the hydrogen storage tank distributes hydrogen to the hydrogen fuel cell anode and combustion chamber. The power supply to the electric motor is allocated based on the output status of the hydrogen fuel cell and the charge status of the lithium battery. Adjust the opening of the built-in flow valve of each nozzle and the angle of each nozzle according to the target attitude to make each nozzle output differential flow and / or differential injection direction; When abnormal temperatures occur in the hydrogen, combustion chamber, nozzle, fuel cell, lithium battery, or housing, the system switches to speed reduction, valve closure, flow restriction, and nozzle return to its lowering position control.

[0019] Compared with the prior art, the beneficial effects of the present invention are: The propulsion system employed in this invention abandons the mechanical coupling method of turbine-driven compressors found in traditional backpack-mounted aircraft, instead using an electric motor as the sole power source for both the compressor and the fan. Under this architecture, the compressor's rotational speed is no longer constrained by the combustion chamber's operating state or the turbine's temperature resistance; instead, it can be independently adjusted by the controller according to the system's actual air demand, ensuring the compressor operates within its high-efficiency range at all stages of flight. Simultaneously, the compressed air at the compressor outlet is divided into two paths: one supplying the cathode of the hydrogen fuel cell, and the other supplying the combustion chamber as an oxidant. The flow rates of these two air paths are controlled by their respective independent regulating valves, achieving decoupling between the constant-pressure air supply required for stable power generation by the fuel cell and the variable air supply required for rapid thrust adjustment by the combustion chamber. Similarly, the hydrogen in the hydrogen storage tank is also divided into two paths, one leading to the anode of the hydrogen fuel cell and the other to the combustion chamber. The flow rates of these two hydrogen paths are also regulated by independent valves, allowing the two hydrogen-using paths—electrochemical reaction power generation and combustion heating jet—to be independently managed without interference. All the high-temperature combustion gases produced in the combustion chamber are directly distributed to multiple nozzles with independently adjustable flow rates and injection angles, without requiring turbine work. Therefore, the gas temperature at the nozzle inlet is not limited by the temperature resistance limit of the turbine material, allowing for a higher usable enthalpy drop within the material's tolerance range. Furthermore, the hydrogen fuel cell and lithium battery form a hybrid power source, with the controller dynamically distributing their output power according to flight conditions, enabling the system to provide both continuous power supply and transient power compensation capabilities.

[0020] By eliminating the turbine, the compressor is directly driven by an electric motor, significantly simplifying the mechanical structure of the entire propulsion system. This reduces the number of high-temperature, high-speed rotating components, lowering manufacturing and maintenance complexity. Simultaneously, the compressor speed can be independently adjusted, avoiding off-design efficiency losses caused by turbine coupling and helping to reduce compressed air power consumption.

[0021] The dual-supply structure at the compressor outlet allows for separate control of the cathode gas supply and the oxidant gas supply in the combustion chamber of the fuel cell. This resolves the contradiction between the fuel cell's need for a stable gas supply and the combustion chamber's need for rapid adjustment of the gas supply according to thrust requirements, thus ensuring the stability of fuel cell power generation and the flexibility of the combustion chamber's thrust response.

[0022] The dual-supply structure of the hydrogen storage tank allows hydrogen to be used for both electrochemical reaction power generation and combustion heating jetting. The flow rates of the two hydrogen use pathways are independently adjustable, which improves the overall utilization efficiency of the same fuel source and simplifies the fuel supply system.

[0023] The high-temperature gas generated in the combustion chamber enters the nozzle directly, without the turbine extracting energy from the gas. Therefore, under the same combustion conditions, the nozzle can obtain a higher gas temperature and a larger expansion ratio, which is beneficial to increasing the jet velocity and the thrust generated per unit mass of gas.

[0024] Each nozzle has independent flow rate adjustment and angle swing capability. The controller can differentially adjust the gas flow rate and jet direction of each nozzle to achieve pitch, roll, yaw and climb control of the flight backpack. Compared with fixed nozzle or single nozzle solutions, the attitude adjustment has higher freedom and precision, and no additional control surfaces or reaction control systems are required.

[0025] The hybrid power supply strategy of hydrogen fuel cells and lithium batteries enables the system to meet both long range and high power transient requirements: the hydrogen fuel cell provides continuous power during stable flight, while the lithium battery provides compensation during instantaneous high power conditions such as takeoff, acceleration, and attitude adjustment. The two work together to extend the range and ensure the dynamic response speed of the power system. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the hydrogen hybrid propulsion system of the electric turbineless flying backpack described in this invention; Figure 2 This is a schematic diagram of the overall structure of the electric turbine-free flight backpack described in this invention; Figure 3 This is a schematic diagram of the rear structure of the electric turbine-free flight backpack described in this invention; Figure 4 This is a schematic diagram of the internal component arrangement of the electric turbine-free flight backpack described in this invention; Figure 5 This is a schematic diagram of the gas delivery pipeline connection of the hydrogen hybrid propulsion system described in this invention; Figure 6 This is a partial structural diagram of the fan, compressor, and air supply pipeline described in this invention.

[0027] In the picture: 1-Electric motor, 2-DC / DC converter and inverter, 3-Lithium battery, 4-Hydrogen fuel cell, 6-Hydrogen storage tank, 7-Fan, 8-Compressor, 9-First air supply channel valve, 10-Second air supply channel valve, 11-Controller, 12-First air supply channel, 13-Second air supply channel, 14-Combustion chamber, 15-Combustion chamber valve, 16-First nozzle, 17-Second nozzle, 18-Third nozzle, 19-Fourth nozzle, 20-Flight handle, 21-Seat 22-Seat belt, 23-Fan-compressor ventilation line, 24-Hydrogen storage tank-combustion chamber ventilation line, 25-Hydrogen storage tank-hydrogen fuel cell ventilation line, 26-Combustion chamber-first nozzle ventilation line, 27-Combustion chamber-second nozzle ventilation line, 28-Combustion chamber-third nozzle ventilation line, 29-Combustion chamber-fourth nozzle ventilation line, 30-Box, 31-Wing, 32-Sensor assembly, 51-First hydrogen branch valve, 52-Second hydrogen branch valve. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0029] Implementation Method 1: This implementation method proposes an electric turbineless flying backpack employing a hydrogen hybrid propulsion system, the flying backpack comprising: The enclosure, and the electric motor, DC / DC converter and inverter, lithium battery, hydrogen fuel cell, hydrogen storage tank, fan, compressor, first air supply channel, second air supply channel, combustion chamber, combustion chamber valve, first nozzle, second nozzle, third nozzle, fourth nozzle, first air supply channel valve, second air supply channel valve, first hydrogen branch valve, second hydrogen branch valve, flight handle, sensor assembly and controller mounted on the enclosure; The electric motor is connected to the fan and the compressor respectively, and the compressor is driven by the electric motor and has no gas turbine mechanical transmission path; The hydrogen fuel cell and lithium battery are electrically connected to the electric motor via a DC / DC converter and an inverter, respectively, forming a hybrid power supply circuit. The fan outlet is connected to the compressor inlet via a fan-compressor air supply line. The compressor outlet is connected to the hydrogen fuel cell cathode inlet and the combustion chamber air inlet via a first air supply channel and a second air supply channel, respectively. The first air supply channel is equipped with a first air supply channel valve, and the second air supply channel is equipped with a second air supply channel valve. The outlet of the hydrogen storage tank is connected to the anode inlet of the hydrogen fuel cell and the hydrogen supply port of the combustion chamber through the hydrogen storage tank-hydrogen fuel cell ventilation pipeline and the hydrogen storage tank-combustion chamber ventilation pipeline, respectively. The hydrogen storage tank-hydrogen fuel cell ventilation pipeline is equipped with a first hydrogen branch valve and the hydrogen storage tank-combustion chamber ventilation pipeline is equipped with a second hydrogen branch valve. The combustion chamber is equipped with a single combustion chamber. The combustion chamber outlet is connected to the inlet of the first nozzle, the second nozzle, the third nozzle and the fourth nozzle respectively through the combustion chamber valve. Each nozzle is equipped with an independent nozzle built-in flow valve and an independent nozzle angle adjustment mechanism. The flight handle is used to input flight commands to the controller, and the sensor assembly is used to collect the operating parameters of the electric motor, compressor, hydrogen fuel cell, lithium battery, combustion chamber, nozzles and pipelines and transmit them to the controller. The controller controls the motor speed, the first air supply channel valve, the second air supply channel valve, the first hydrogen branch valve, the second hydrogen branch valve, the combustion chamber valve, the built-in flow valve of each nozzle, and the nozzle angle adjustment mechanism according to the flight handle command and sensor component parameters.

[0030] In this embodiment, in the hybrid power supply circuit, the hydrogen fuel cell supplies power to the motor via a DC / DC converter and inverter, and the lithium battery supplies power to the motor via the same or parallel DC / DC converter and inverter. The controller allocates the output power of the hydrogen fuel cell and the lithium battery according to the flight status. During stable flight, the hydrogen fuel cell is the main power source. During takeoff, acceleration, attitude adjustment, or sudden thrust changes, the controller controls the lithium battery to supplement the power supply to the motor. When the hydrogen fuel cell output is in surplus, the lithium battery is charged via the DC / DC converter and inverter.

[0031] In this embodiment, the fan and compressor are coaxial and connected to the same motor via a coupling or gear transmission; in the fan-compressor air supply pipeline, the fan outlet is set before the compressor inlet, and the external air enters the first air supply channel and the second air supply channel after being pressurized by the fan and compressed by the compressor in sequence; the controller adjusts the opening of the valves of the first air supply channel and the second air supply channel according to the air demand of the hydrogen fuel cell cathode and the air demand of the combustion chamber respectively.

[0032] In this embodiment, the hydrogen storage tank-hydrogen fuel cell ventilation pipeline supplies reactive hydrogen to the anode of the hydrogen fuel cell, and the hydrogen storage tank-combustion chamber ventilation pipeline supplies combustion hydrogen to the combustion chamber. The controller adjusts the valve of the first hydrogen branch according to the hydrogen demand of the hydrogen fuel cell anode, and adjusts the valve of the second hydrogen branch according to the combustion equivalent and target heat load of the combustion chamber. The hydrogen flow distribution of the hydrogen storage tank-hydrogen fuel cell ventilation pipeline and the hydrogen storage tank-combustion chamber ventilation pipeline is performed independently of the compressor air distribution.

[0033] In this embodiment, the first nozzle, the second nozzle, the third nozzle, and the fourth nozzle are distributed on the rear side or the periphery of the housing; each nozzle has a built-in flow valve that independently controls the flow rate of the high-temperature gas obtained from the combustion chamber valve, and each nozzle angle adjustment mechanism independently controls the swing of the corresponding nozzle around the mounting axis; the controller adjusts the longitudinal thrust difference, the lateral thrust difference, and the yaw differential thrust respectively through the combination of the built-in flow valve and the nozzle angle adjustment mechanism.

[0034] In this embodiment, the sensor assembly includes a motor speed sensor, a compressor outlet pressure sensor, a gas supply channel flow sensor, a hydrogen pressure sensor, a hydrogen flow sensor, a combustion chamber temperature sensor, a nozzle flow sensor, a nozzle angle sensor, a hydrogen fuel cell output status sensor, a lithium battery charge sensor, and a housing temperature sensor. The controller adjusts the motor speed, the first gas supply channel valve, the second gas supply channel valve, the first hydrogen branch valve, the second hydrogen branch valve, the combustion chamber valve, the built-in flow valve of each nozzle, and the angle of each nozzle based on the sensor parameters in a closed loop.

[0035] Furthermore, when the sensor assembly outputs abnormal hydrogen pressure, abnormal hydrogen flow, combustion chamber temperature exceeding the preset range, abnormal nozzle flow, abnormal nozzle angle, abnormal hydrogen fuel cell output, abnormal lithium battery charge, or abnormal housing temperature, the controller performs the following protective control actions: reducing the motor speed, reducing or closing the first hydrogen branch valve and / or the second hydrogen branch valve, closing the combustion chamber valve, limiting the opening of the built-in flow valve of each nozzle, and adjusting the angle of each nozzle to the predetermined landing posture.

[0036] In this embodiment, the housing is made of flame-retardant material and has an explosion-proof structure; the outer surface of the hydrogen storage tank, the hydrogen storage tank-hydrogen fuel cell ventilation pipeline, the hydrogen storage tank-combustion chamber ventilation pipeline, the outer wall of the combustion chamber, the pipeline from the combustion chamber valve to each nozzle, and the outer wall of each nozzle are all provided with heat insulation layers; a seat and safety belt are provided on the side of the housing near the human body, and wings are provided on both sides of the housing. These wings and the nozzle thrust control independently provide auxiliary lift or attitude stability.

[0037] In this embodiment, the DC / DC converter and inverter include a DC / DC converter and an inverter. The hydrogen fuel cell and the lithium battery are connected to the DC bus through their respective or common DC / DC converters, and then the inverter supplies power to the motor. The controller jointly regulates the DC bus voltage, the hydrogen fuel cell output current, the lithium battery charging and discharging current and the three-phase current of the motor to match the power requirements of the compressor, fan and nozzle under variable thrust conditions.

[0038] Implementation Method Two: This implementation method provides a complete embodiment of the electric turbineless flying backpack using a hydrogen hybrid propulsion system described in Implementation Method One, including: like Figures 1 to 6 As shown, this embodiment provides an electric turbineless flying backpack using a hydrogen hybrid propulsion system, including a housing 30, and an electric motor 1, a DC / DC converter and inverter 2, a lithium battery 3, a hydrogen fuel cell 4, a hydrogen storage tank 6, a fan 7, a compressor 8, a first air supply channel 12, a second air supply channel 13, a combustion chamber 14, a combustion chamber valve 15, a first nozzle 16, a second nozzle 17, a third nozzle 18, a fourth nozzle 19, a first air supply channel valve 9, a second air supply channel valve 10, a first hydrogen branch valve 51, a second hydrogen branch valve 52, a flight handle 20, a sensor assembly 32, and a controller 11, all installed inside or on the housing 30.

[0039] Electric motor 1 is connected to fan 7 and compressor 8 via a transmission connection. Electric motor 1 drives fan 7 and compressor 8. Fan 7 is used to introduce outside air, and compressor 8 is used to compress the air. In this system, compressor 8 is directly or indirectly driven by electric motor 1; there is no gas turbine to drive the compressor. Electric motor 1 can be connected to fan 7 and compressor 8 via coaxial drive, coupling drive, gear drive, or other suitable transmission methods.

[0040] The hydrogen fuel cell 4 and lithium battery 3 are electrically connected to the electric motor 1 via a DC / DC converter and inverter 2, forming a hybrid power supply circuit. The hydrogen fuel cell 4 serves as the primary power source, while the lithium battery 3 provides transient auxiliary power. The DC / DC converter and inverter 2 convert electrical energy and output the required electrical energy to the electric motor 1. During stable flight, the hydrogen fuel cell 4 primarily supplies power to the electric motor 1 and can also charge the lithium battery 3. During takeoff, acceleration, attitude adjustments, or sudden thrust changes, the lithium battery 3 and hydrogen fuel cell 4 jointly supply power to the electric motor 1 to achieve a balance between continuous power supply and transient power compensation.

[0041] The air outlet of fan 7 is through the fan Compressor air supply line 23 connects to the air inlet of compressor 8. External air is first introduced by fan 7 and then enters compressor 8 for compression. The air outlet of compressor 8 is connected to the first air supply channel 12 and the second air supply channel 13. The first air supply channel 12 is connected to the cathode air inlet of hydrogen fuel cell 4, and the second air supply channel 13 is connected to the air inlet of combustion chamber 14. The first air supply channel 12 is equipped with a first air supply channel valve 9, and the second air supply channel 13 is equipped with a second air supply channel valve 10. The first air supply channel 12 supplies compressed air to hydrogen fuel cell 4, and the second air supply channel 13 supplies compressed air to combustion chamber 14. Controller 11 controls the airflow into hydrogen fuel cell 4 and combustion chamber 14 by adjusting the opening of the first air supply channel valve 9 and the second air supply channel valve 10, respectively.

[0042] Hydrogen storage tank 6 is used to store hydrogen gas. The outlet of hydrogen storage tank 6 is connected to the hydrogen storage tank... The hydrogen fuel cell venting line 25 is connected to the anode inlet of the hydrogen fuel cell 4 and passes through a hydrogen storage tank. The combustion chamber vent pipe 24 is connected to the hydrogen supply port of the combustion chamber 14. Hydrogen storage tank. The hydrogen fuel cell gas supply line 25 is equipped with a first hydrogen branch valve 51 and a hydrogen storage tank. A second hydrogen branch valve 52 is provided on the combustion chamber ventilation line 24. The first hydrogen branch valve 51 is used to regulate the flow rate of hydrogen entering the hydrogen fuel cell 4, and the second hydrogen branch valve 52 is used to regulate the flow rate of hydrogen entering the combustion chamber 14.

[0043] The hydrogen fuel cell 4 receives compressed air from the first air supply channel 12 and from the hydrogen storage tank. Hydrogen gas in the hydrogen fuel cell inlet 25 generates electricity through an electrochemical reaction. The combustion chamber 14 receives compressed air from the second gas supply channel 13 and from the hydrogen storage tank. Hydrogen gas in combustion chamber ventilation pipe 24 is burned with compressed air in combustion chamber 14 to generate high-temperature fuel gas.

[0044] There is one combustion chamber 14, and its outlet is equipped with a combustion chamber valve 15. The outlet of the combustion chamber valve 15 is connected to the combustion chamber... First nozzle ventilation pipe 26, combustion chamber Second nozzle ventilation pipe 27, combustion chamber Third nozzle ventilation pipe 28 and combustion chamber The fourth nozzle vent pipe 29 is connected to the inlets of the first nozzle 16, the second nozzle 17, the third nozzle 18, and the fourth nozzle 19. The first nozzle 16, the second nozzle 17, the third nozzle 18, and the fourth nozzle 19 are used to eject the high-temperature gas generated in the combustion chamber 14 to generate thrust. Each nozzle has an independent built-in flow valve to control the gas supply to the corresponding nozzle individually. Each nozzle also has an independent nozzle angle adjustment mechanism, allowing each nozzle to rotate independently. The controller 11 controls the flight backpack's altitude, pitch, roll, and yaw attitude by adjusting the built-in flow valves and the nozzle angle adjustment mechanisms of each nozzle.

[0045] The flight handle 20 is used to input flight operation signals to the controller 11, including takeoff, landing, acceleration, deceleration, hovering, steering, and attitude adjustment signals. The sensor assembly 32 is used to collect operational data from the flight backpack, including a motor speed sensor, a compressor outlet pressure sensor, an air supply channel flow sensor, a hydrogen pressure sensor, a hydrogen flow sensor, a combustion chamber temperature sensor, a nozzle flow sensor, a nozzle angle sensor, a hydrogen fuel cell output status sensor, a lithium battery charge sensor, and a casing temperature sensor. The sensor assembly 32 feeds back the collected operational data to the controller 11. Based on the operational data fed back by the sensor assembly 32 and the flight operation signals input from the flight handle 20, the controller 11 adjusts the speed of the motor 1, the opening of the first air supply channel valve 9, the opening of the second air supply channel valve 10, the opening of the first hydrogen branch valve 51, the opening of the second hydrogen branch valve 52, the opening of the combustion chamber valve 15, the opening of the internal flow valves of each nozzle, and the angle of each nozzle.

[0046] In a specific operation, the user inputs a takeoff command via the flight handle 20. Upon receiving the takeoff command, the controller 11 increases the speed of the motor 1. The fan 7 introduces outside air, and the compressor 8 compresses the air. The controller 11 opens the first air supply channel valve 9 and the second air supply channel valve 10, allowing compressed air to enter the hydrogen fuel cell 4 and the combustion chamber 14, respectively. Simultaneously, the controller 11 opens the first hydrogen branch valve 51 and the second hydrogen branch valve 52, allowing hydrogen from the hydrogen storage tank 6 to enter the hydrogen fuel cell 4 and the combustion chamber 14, respectively. The hydrogen fuel cell 4 generates electricity, which powers the motor 1 via the DC / DC converter and inverter 2. The lithium battery 3 replenishes the motor 1 with electricity during takeoff. The hydrogen in the combustion chamber 14 burns with the compressed air to generate high-temperature fuel gas, which enters the four combustion chambers via the combustion chamber valve 15. The exhaust pipes then flow into the first nozzle 16, the second nozzle 17, the third nozzle 18, and the fourth nozzle 19, respectively. The four nozzles expel high-temperature exhaust gases, generating thrust that lifts the flight pack off the ground.

[0047] During stable flight, the controller 11 performs closed-loop control of the system based on feedback from the sensor assembly 32 regarding the motor speed, air flow, hydrogen flow, combustion chamber temperature, nozzle flow, nozzle angle, hydrogen fuel cell output status, and lithium battery charge. The controller 11 adjusts the first air supply channel valve 9 to ensure stable cathode air intake for the hydrogen fuel cell 4; adjusts the second air supply channel valve 10 and the first hydrogen branch valve 51 and the second hydrogen branch valve 52 to ensure the combustion chamber 14 receives the required air and hydrogen; and adjusts the combustion chamber valve 15 and the built-in flow valves of each nozzle to ensure that each nozzle outputs the target thrust.

[0048] When the user inputs steering or attitude adjustment signals via the flight handle 20, the controller 11 adjusts the injection angle and gas flow of each nozzle according to the target attitude. When pitch adjustment is required, the controller 11 changes the thrust distribution or injection direction of the front and rear nozzles; when roll adjustment is required, the controller 11 changes the thrust distribution or injection direction of the left and right nozzles; when yaw adjustment is required, the controller 11 controls different nozzles to generate differential thrust.

[0049] When the flight backpack needs a short-term increase in thrust, the controller 11 increases the speed of the motor 1 and increases the opening of the second air supply channel valve 10, the second hydrogen branch valve 52, and the combustion chamber valve 15. The lithium battery 3 replenishes the motor 1 with electrical energy, increasing the air intake and hydrogen supply to the combustion chamber 14, thereby increasing the nozzle thrust.

[0050] When the flight pack enters cruise or stable hovering mode, the controller 11 reduces the output ratio of the lithium battery 3, and the hydrogen fuel cell 4 serves as the main power source to supply power to the electric motor 1. If the lithium battery 3's charge level falls below a set value, the controller 11 controls the hydrogen fuel cell 4 to charge the lithium battery 3.

[0051] When sensor assembly 32 detects an abnormal state, controller 11 enters a protection control state. Abnormal states include one or more of the following: abnormal hydrogen pressure, abnormal hydrogen flow rate, combustion chamber temperature exceeding a preset range, abnormal nozzle flow rate, abnormal nozzle angle, abnormal motor speed, abnormal housing temperature, abnormal hydrogen fuel cell output, and abnormal lithium battery charge. In the protection control state, controller 11 performs one or more of the following actions: reducing the speed of motor 1, partially or completely closing the first hydrogen branch valve 51 and / or the second hydrogen branch valve 52, closing the combustion chamber valve 15, limiting the opening of the built-in flow valves in each nozzle, and adjusting the angle of each nozzle to a predetermined landing posture, in order to reduce safety risks during hydrogen supply, combustion heating, and high-temperature gas delivery.

[0052] The enclosure 30 is used to install and protect the electric motor 1, DC / DC converter and inverter 2, lithium battery 3, hydrogen fuel cell 4, hydrogen storage tank 6, fan 7, compressor 8, controller 11, combustion chamber 14, and related piping. The enclosure 30 is made of flame-retardant material and has an explosion-proof structure. (The text also mentions the outer surface of the hydrogen storage tank 6.) Hydrogen fuel cell venting line 25, hydrogen storage tank The combustion chamber ventilation pipe 24, the outer wall of the combustion chamber 14, the pipes from the combustion chamber valve 15 to each nozzle, and the outer wall of each nozzle are all equipped with heat insulation layers. A seat 21 and a safety belt 22 are located on the side of the casing 30 closest to the user to secure them to the flight backpack. Wings 31 are located on both sides of the casing 30. The wings 31 provide auxiliary lift during flight and improve flight attitude stability; the wings 31 are independent of the nozzle thrust control.

[0053] As can be seen from the above description of the structure and working method, the present invention achieves continuous power supply, rapid thrust adjustment and flexible attitude control of the backpack flight platform under turbine-less conditions by independently driving the fan and compressor with an electric motor, decoupled control of dual air supply and dual hydrogen supply, turbine-less direct-exhaust multi-nozzle thrust adjustment and hybrid power supply collaborative management, while also having multiple safety protection mechanisms.

[0054] Implementation Method 3: This implementation method proposes a control method for an electric turbineless flying backpack using a hydrogen hybrid propulsion system, based on any one of Implementation Methods 1 to 2, comprising: It acquires the target flight command issued by the flight handle and the parameters of the electric motor, compressor, hydrogen fuel cell, lithium battery, combustion chamber, nozzles and pipelines collected by the sensor components; Determine the target's total thrust and target attitude based on the target's flight commands and parameters; Adjust the motor speed according to the target total thrust, and adjust the first air supply channel valve, the second air supply channel valve, the first hydrogen branch valve, the second hydrogen branch valve and the combustion chamber valve respectively, so that the compressor distributes compressed air to the hydrogen fuel cell cathode and combustion chamber, and the hydrogen storage tank distributes hydrogen to the hydrogen fuel cell anode and combustion chamber. The power supply to the electric motor is allocated based on the output status of the hydrogen fuel cell and the charge status of the lithium battery. Adjust the opening of the built-in flow valve of each nozzle and the angle of each nozzle according to the target attitude to make each nozzle output differential flow and / or differential injection direction; When abnormal temperatures occur in the hydrogen, combustion chamber, nozzle, fuel cell, lithium battery, or housing, the system switches to speed reduction, valve closure, flow restriction, and nozzle return to its lowering position control.

[0055] The specific embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. An electric turbineless flying backpack employing a hydrogen hybrid propulsion system, characterized in that, The flight backpack includes: The enclosure, and the electric motor, DC / DC converter and inverter, lithium battery, hydrogen fuel cell, hydrogen storage tank, fan, compressor, first air supply channel, second air supply channel, combustion chamber, combustion chamber valve, first nozzle, second nozzle, third nozzle, fourth nozzle, first air supply channel valve, second air supply channel valve, first hydrogen branch valve, second hydrogen branch valve, flight handle, sensor assembly and controller mounted on the enclosure; The electric motor is connected to the fan and the compressor respectively, and the compressor is driven by the electric motor and has no gas turbine mechanical transmission path; The hydrogen fuel cell and lithium battery are electrically connected to the electric motor via a DC / DC converter and an inverter, respectively, forming a hybrid power supply circuit. The fan outlet is connected to the compressor inlet via a fan-compressor air supply line. The compressor outlet is connected to the hydrogen fuel cell cathode inlet and the combustion chamber air inlet via a first air supply channel and a second air supply channel, respectively. The first air supply channel is equipped with a first air supply channel valve, and the second air supply channel is equipped with a second air supply channel valve. The outlet of the hydrogen storage tank is connected to the anode inlet of the hydrogen fuel cell and the hydrogen supply port of the combustion chamber through the hydrogen storage tank-hydrogen fuel cell ventilation pipeline and the hydrogen storage tank-combustion chamber ventilation pipeline, respectively. The hydrogen storage tank-hydrogen fuel cell ventilation pipeline is equipped with a first hydrogen branch valve and the hydrogen storage tank-combustion chamber ventilation pipeline is equipped with a second hydrogen branch valve. The combustion chamber is equipped with a single combustion chamber. The combustion chamber outlet is connected to the inlet of the first nozzle, the second nozzle, the third nozzle and the fourth nozzle respectively through the combustion chamber valve. Each nozzle is equipped with an independent nozzle built-in flow valve and an independent nozzle angle adjustment mechanism. The flight handle is used to input flight commands to the controller, and the sensor assembly is used to collect the operating parameters of the electric motor, compressor, hydrogen fuel cell, lithium battery, combustion chamber, nozzles and pipelines and transmit them to the controller. The controller controls the motor speed, the first air supply channel valve, the second air supply channel valve, the first hydrogen branch valve, the second hydrogen branch valve, the combustion chamber valve, the built-in flow valve of each nozzle, and the nozzle angle adjustment mechanism according to the flight handle command and sensor component parameters.

2. The electric turbineless flying backpack employing a hydrogen hybrid propulsion system according to claim 1, characterized in that, In the hybrid power supply circuit, the hydrogen fuel cell supplies power to the motor via a DC / DC converter and inverter, while the lithium battery supplies power to the motor via the same or parallel DC / DC converter and inverter. The controller allocates the output power of the hydrogen fuel cell and the lithium battery according to the flight status. During stable flight, the hydrogen fuel cell is the main power source. During takeoff, acceleration, attitude adjustment, or sudden thrust changes, the controller controls the lithium battery to supplement the power supply to the motor. When the hydrogen fuel cell output is in surplus, the lithium battery is charged via the DC / DC converter and inverter.

3. The electric turbineless flying backpack employing a hydrogen hybrid propulsion system according to claim 1, characterized in that, The fan and compressor are coaxial and connected to the same motor via a coupling or gear drive; in the fan-compressor air supply pipeline, the fan outlet is set before the compressor inlet, and the external air enters the first air supply channel and the second air supply channel after being pressurized by the fan and compressed by the compressor in sequence; the controller adjusts the opening of the valves of the first air supply channel and the second air supply channel according to the air demand of the hydrogen fuel cell cathode and the air demand of the combustion chamber respectively.

4. The electric turbineless flying backpack employing a hydrogen hybrid propulsion system according to claim 1, characterized in that, The hydrogen storage tank-hydrogen fuel cell ventilation pipeline supplies reactive hydrogen to the anode of the hydrogen fuel cell, and the hydrogen storage tank-combustion chamber ventilation pipeline supplies combustion hydrogen to the combustion chamber. The controller adjusts the valve of the first hydrogen branch according to the hydrogen demand of the hydrogen fuel cell anode, and adjusts the valve of the second hydrogen branch according to the combustion equivalent and target heat load of the combustion chamber. The hydrogen flow distribution of the hydrogen storage tank-hydrogen fuel cell ventilation pipeline and the hydrogen storage tank-combustion chamber ventilation pipeline is performed independently of the compressor air distribution.

5. An electric turbineless flying backpack employing a hydrogen hybrid propulsion system according to claim 1, characterized in that, The first, second, third, and fourth nozzles are distributed on the rear or periphery of the housing; each nozzle has a built-in flow valve that independently controls the flow rate of the high-temperature gas obtained from the combustion chamber valve; each nozzle angle adjustment mechanism independently controls the swing of the corresponding nozzle around the mounting axis; the controller adjusts the longitudinal thrust difference, lateral thrust difference, and yaw differential thrust respectively through the combination of the built-in flow valves and nozzle angle adjustment mechanisms of each nozzle.

6. The electric turbineless flying backpack employing a hydrogen hybrid propulsion system according to claim 1, characterized in that, The sensor assembly includes a motor speed sensor, a compressor outlet pressure sensor, an air supply channel flow sensor, a hydrogen pressure sensor, a hydrogen flow sensor, a combustion chamber temperature sensor, a nozzle flow sensor, a nozzle angle sensor, a hydrogen fuel cell output status sensor, a lithium battery charge sensor, and a housing temperature sensor. The controller uses sensor parameters to perform closed-loop regulation of the motor speed, the first air supply channel valve, the second air supply channel valve, the first hydrogen branch valve, the second hydrogen branch valve, the combustion chamber valve, the built-in flow valves of each nozzle, and the angle of each nozzle.

7. An electric turbineless flying backpack employing a hydrogen hybrid propulsion system according to claim 6, characterized in that, When the sensor components output abnormal hydrogen pressure, abnormal hydrogen flow, combustion chamber temperature exceeding the preset range, abnormal nozzle flow, abnormal nozzle angle, abnormal hydrogen fuel cell output, abnormal lithium battery charge, or abnormal housing temperature, the controller performs the following protective control actions: reducing motor speed, reducing or closing the first hydrogen branch valve and / or the second hydrogen branch valve, closing the combustion chamber valve, limiting the opening of the built-in flow valve of each nozzle, and adjusting the angle of each nozzle to the predetermined landing posture.

8. The electric turbineless flying backpack employing a hydrogen hybrid propulsion system according to claim 1, characterized in that, The enclosure is made of flame-retardant material and has an explosion-proof structure; the outer surface of the hydrogen storage tank, the hydrogen storage tank-hydrogen fuel cell ventilation pipeline, the hydrogen storage tank-combustion chamber ventilation pipeline, the outer wall of the combustion chamber, the pipeline from the combustion chamber valve to each nozzle, and the outer wall of each nozzle are all provided with heat insulation layers; the enclosure is equipped with a seat and safety belt on the side closest to the human body, and wings are provided on both sides of the enclosure. These wings and the nozzle thrust control independently provide auxiliary lift or attitude stabilization.

9. An electric turbineless flying backpack employing a hydrogen hybrid propulsion system according to claim 1, characterized in that, The DC / DC converter and inverter include a DC / DC converter and an inverter. The hydrogen fuel cell and the lithium battery are connected to the DC bus through their respective or common DC / DC converters, and then the inverter supplies power to the motor. The controller jointly regulates the DC bus voltage, the hydrogen fuel cell output current, the lithium battery charging and discharging current and the three-phase current of the motor to match the power requirements of the compressor, fan and nozzle under variable thrust conditions.

10. A control method for an electric turbineless flying backpack employing a hydrogen hybrid propulsion system as described in any one of claims 1 to 9, characterized in that, include: It acquires the target flight command issued by the flight handle and the parameters of the electric motor, compressor, hydrogen fuel cell, lithium battery, combustion chamber, nozzles and pipelines collected by the sensor components; Determine the target's total thrust and target attitude based on the target's flight commands and parameters; Adjust the motor speed according to the target total thrust, and adjust the first air supply channel valve, the second air supply channel valve, the first hydrogen branch valve, the second hydrogen branch valve and the combustion chamber valve respectively, so that the compressor distributes compressed air to the hydrogen fuel cell cathode and combustion chamber, and the hydrogen storage tank distributes hydrogen to the hydrogen fuel cell anode and combustion chamber. The power supply to the electric motor is allocated based on the output status of the hydrogen fuel cell and the charge status of the lithium battery. Adjust the opening of the built-in flow valve of each nozzle and the angle of each nozzle according to the target attitude to make each nozzle output differential flow and / or differential injection direction; When abnormal temperatures occur in the hydrogen, combustion chamber, nozzle, fuel cell, lithium battery, or housing, the system switches to speed reduction, valve closure, flow restriction, and nozzle return to its lowering position control.

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