Hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen and helium heat exchange cooling

Abstract

The invention belongs to the technical field of aviation electric propulsion, and relates to a hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen and helium heat exchange cooling, which is suitable for megawatt level branch aircrafts and comprises a liquid hydrogen storage tank, a hydrogen and helium heat exchanger, a hydrogen fuel cell, a lithium battery, an inverter, a superconducting motor, a propeller and other core components. The liquid hydrogen storage tank vaporizes liquid hydrogen through the micro-channel plate type hydrogen-helium heat exchanger and stably supplies the vaporized liquid hydrogen to the hydrogen fuel cell to generate electric energy; helium is used for a low-temperature cooling loop and cooling key assemblies such as a superconducting motor, a low-temperature inverter, a superconducting cable and a hydrogen fuel cell, and it is ensured that the key assemblies stably operate at the optimal working temperature. The hydrogen fuel cell and the lithium battery cooperatively provide electric energy for the superconducting electric propulsion system, the integrated energy management controller dynamically adjusts the output power of the fuel cell and the lithium battery by adopting a state machine strategy, and accurate monitoring and optimal distribution of working parameters of all components are achieved. The optimal heat balance and power output are ensured to be realized in different flight stages such as takeoff, cruise and landing; according to the hydrogen fuel cell hybrid electric propulsion system based on hydrogen and helium heat exchange cooling, the power generation efficiency and the operation stability of the hydrogen fuel cell are remarkably improved, the overall energy conversion efficiency is improved, and the high-power and high-efficiency power extraction requirements of megawatt aircrafts are fully met.

Description

Technical Field

[0001] The present invention belongs to the field of aviation electric propulsion technology, and more specifically, relates to a hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling technology. Background Art

[0002] The power system in today's aviation field mainly relies on traditional aviation gas turbine engines. Although they have high power density and good performance, they have low energy efficiency and emit a large amount of harmful gases such as carbon dioxide and nitrogen oxides. With the increasing global demand for green aviation, reducing aircraft carbon emissions and improving fuel efficiency have become key challenges that the aviation industry needs to solve. In addition, the complexity and high maintenance costs of traditional power systems also limit their application in high-power regional aircraft. Therefore, the development of environmentally friendly, efficient and reliable alternative propulsion systems has become an important research direction for the aviation industry.

[0003] Hydrogen fuel cell propulsion systems have significant advantages such as zero emissions, low noise and high efficiency, but they face many technical challenges in actual airborne applications. Hydrogen fuel cells have relatively low power density and it is difficult to meet the energy needs of aircraft in high-power demand stages such as takeoff and climb. In addition, traditional propulsion components are heavy and inefficient, making it difficult to meet the aircraft's needs for lightweight and high efficiency, making it difficult for propulsion systems that rely solely on hydrogen fuel cells to meet the performance and endurance requirements of megawatt-class regional aircraft. Therefore, hybrid electric propulsion systems have gradually become a viable solution. By combining hydrogen fuel cell / lithium battery hybrid power and superconducting electrical propulsion technology, they can better meet the aircraft's high-power and high power-to-weight ratio propulsion needs.

[0004] Hydrogen fuel cells generate a lot of heat when they are outputting at high power, and traditional heat dissipation methods such as air cooling or liquid cooling cannot effectively meet the cooling needs of fuel cells. At the same time, components such as superconducting motors and superconducting cables must maintain extremely low temperatures during operation to maintain their superconducting state in order to achieve efficient operation. Therefore, the integrated thermal management system must be able to efficiently meet the different cooling needs of hydrogen fuel cells and superconducting motors at the same time, ensuring that the system operates stably under various flight conditions and achieves high-efficiency output.

[0005] In response to the above problems, the present invention proposes a hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling, which aims to solve the cooling and thermal management challenges of hydrogen fuel cells and superconducting motors in megawatt-class regional aircraft. The system adopts a hydrogen-helium heat exchange cooling method, utilizing the lightweight properties of hydrogen and the high thermal conductivity of helium to efficiently dissipate the heat generated by the hydrogen fuel cell while meeting the low-temperature cooling requirements of the superconducting motor. Compared with traditional cooling methods, the hydrogen-helium heat exchange cooling system significantly improves the cooling efficiency and reduces the weight and complexity of the system. In addition, the present invention optimizes the power transmission and energy management between hydrogen fuel cells, lithium batteries and superconducting motors to ensure that the system can meet the requirements of megawatt-class regional aircraft for high efficiency and long endurance. Summary of the invention

[0006] In order to solve the problems of low power density and great cooling difficulty of traditional megawatt-class aviation power systems, and to overcome the technical bottlenecks of airborne fuel cell power generation and airborne superconducting motor applications, the present invention proposes a hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling, which integrates liquid hydrogen storage tanks and hydrogen-helium heat exchangers to provide a continuous and stable hydrogen supply for airborne hydrogen fuel cells, and uses helium to efficiently cool superconducting components and cryogenic devices. Hydrogen fuel cells and lithium batteries work together to power the superconducting propulsion systems on both sides of the aircraft through hybrid power, which can flexibly respond to power requirements in different flight phases and ensure high-efficiency, long-endurance and environmentally friendly power output.

[0007] To achieve the above-mentioned purpose, the present invention is a hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling suitable for megawatt-class regional aircraft, characterized in that the system mainly includes liquid hydrogen storage tanks, hydrogen-helium heat exchangers, hydrogen fuel cells, lithium batteries, inverters, superconducting motors and propellers and other components; the liquid hydrogen storage tank vaporizes liquid hydrogen through a microchannel plate hydrogen-helium heat exchanger, and stably supplies hydrogen to the hydrogen fuel cell to generate electricity; the helium circulation is used for a low-temperature cooling circuit to cool components such as superconducting motors, low-temperature inverters, superconducting cables and hydrogen fuel cells; hydrogen fuel cells and lithium batteries work together to provide electrical energy for the superconducting propulsion system, and the parameters of each component are reasonably supervised, allocated and scheduled through an integrated energy management controller to meet the efficient power extraction needs of megawatt-class regional aircraft.

[0008] The microchannel plate hydrogen-helium heat exchanger vaporizes the liquid hydrogen flowing out of the liquid hydrogen storage tank, and the vaporized hydrogen is stably transported to the anode of the hydrogen fuel cell for power generation, thereby achieving a continuous and stable hydrogen supply to the hydrogen fuel cell and ensuring the continuity of power output.

[0009] The helium gas flowing out of the microchannel plate hydrogen-helium heat exchanger enters the cryogenic cooling circuit to efficiently cool key components such as superconducting motors, cryogenic inverters, superconducting cables and hydrogen fuel cells, ensuring that each cryogenic component continues to operate efficiently within the operating temperature range, thereby improving the overall operating stability and reliability of the system.

[0010] The hydrogen fuel cell and lithium battery work together to provide electrical energy for the superconducting propulsion system on both sides of the fuselage. The system thermal management and power distribution are precisely controlled and scheduled through an integrated energy management controller, achieving effective supervision and optimized distribution of the working parameters of each component, ensuring that the system can achieve optimal thermal balance and power output in different flight phases, and meeting the efficient power extraction needs of megawatt-class regional aircraft.

[0011] Preferably, the hydrogen-helium heat exchanger is connected to the liquid hydrogen storage tank via a high-efficiency heat exchange structure, which can quickly vaporize liquid hydrogen under high pressure to achieve a continuous and stable supply of hydrogen fuel cell anode fuel.

[0012] Preferably, the cryogenic cooling circuit adopts a multi-stage cooling design, and the helium gas is circulated multiple times to achieve precise cooling of the superconducting motor, cryogenic inverter and superconducting cable, ensuring that each component is always maintained within the optimal temperature range under different workloads, thereby significantly improving cooling efficiency and component performance.

[0013] Preferably, the integrated energy management controller dynamically adjusts the output power of the hydrogen fuel cell and the lithium battery through a state machine algorithm, optimizes power distribution and thermal energy management according to the power requirements of different flight phases such as take-off, cruising and descent, and ensures that the system achieves optimal energy conversion efficiency in each stage.

[0014] In general, the hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling suitable for megawatt-class branch aircraft of the present invention has the following gains compared with the existing power propulsion system:

[0015] 1 The hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling provided by the present invention realizes efficient hydrogen supply and continuous power generation, and significantly improves the power generation efficiency of the hydrogen fuel cell and the stability of the system operation.

[0016] 2 The present invention improves the cooling efficiency of superconducting motors and cryogenic components through hydrogen-helium heat exchange cooling technology, ensuring stable operation of the system under high load conditions.

[0017] 3 The present invention realizes the optimal power distribution of hydrogen fuel cells and lithium batteries, improves the overall energy conversion efficiency of the system, and fully meets the power extraction requirements of megawatt-class aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention, the drawings in the embodiments are briefly introduced below, which are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation of the present invention.

[0019] Figure 1 It is a schematic diagram of the architecture of a hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling provided by an embodiment;

[0020] Figure 2 Schematic diagram of hydrogen and helium flow paths and cooling process in a hydrogen fuel cell superconducting hybrid electric propulsion system provided in an embodiment;

[0021] Figure 3 It is a schematic diagram of a comprehensive energy management optimization framework of a hydrogen fuel cell superconducting hybrid electric propulsion system based on state machine power allocation and heat balance provided in an embodiment. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Figure 1 The present invention is a schematic diagram of the architecture of a hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling suitable for megawatt-class regional aircraft provided in an embodiment, including components such as hydrogen fuel cells, lithium batteries, inverters, superconducting motors and propellers. Liquid hydrogen storage tanks, hydrogen-helium heat exchangers and helium cooling circuits work together to achieve fuel supply and heat exchange cooling of the system and maintain stable operation of each component at an appropriate temperature.

[0024] The liquid hydrogen storage tank is a hydrogen storage unit in the hydrogen fuel cell superconducting hybrid electric propulsion system, storing cryogenic liquid hydrogen and providing a stable and long-lasting fuel supply.

[0025] Liquid hydrogen is transported through a pipeline to a microchannel plate heat exchanger, where it is vaporized into hydrogen gas, which is then used to provide energy for the fuel cell.

[0026] The microchannel plate hydrogen-helium heat exchanger is responsible for vaporizing the liquid hydrogen transported from the liquid hydrogen storage tank into gaseous hydrogen, ensuring that the hydrogen is used for the electrochemical reaction of the hydrogen fuel cell at a suitable temperature and pressure.

[0027] Hydrogen exchanges heat with helium in the heat exchanger, cooling the helium and maintaining the temperature of the helium circulation loop to maintain the working state of low-temperature components such as superconducting motors, superconducting cables and inverters.

[0028] Hydrogen generates electricity through fuel cells, which serves as the main power source for the hybrid electric propulsion system and provides power for the superconducting propulsion unit.

[0029] As an auxiliary energy source, lithium batteries work together with hydrogen fuel cells to power the system during takeoff, climb, acceleration or conditions with high power demand, ensuring that the power requirements of the aircraft are met at all stages.

[0030] The inverter converts the direct current from the fuel cell and lithium battery into alternating current and supplies it to the superconducting motor, ensuring efficiency and stability during the current conversion process.

[0031] The superconducting motor is powered by a hydrogen fuel cell and a lithium battery, driving the propellers on both sides of the fuselage to achieve propulsion. Its efficient operation depends on a low temperature environment, which is maintained by a helium cooling circuit to ensure that the superconducting properties are maintained and high-efficiency operation is achieved.

[0032] The output power of the superconducting motor directly drives the propeller through a mechanical connection to provide propulsion for the aircraft. The propellers on both sides of the fuselage are driven by two independent superconducting motors to achieve balanced propulsion of the aircraft.

[0033] Figure 2 This is a schematic diagram of the flow path and cooling process of hydrogen and helium in a hydrogen fuel cell superconducting hybrid electric propulsion system provided in an embodiment, which mainly includes hydrogen flow path components such as liquid hydrogen storage tanks, pumps, valves, temperature and pressure sensors, and a microchannel plate hydrogen-helium heat exchanger that vaporizes liquid hydrogen into gaseous hydrogen, while cooling the helium and maintaining a low temperature state in the helium cooling circuit.

[0034] Liquid hydrogen is transported through a cryogenic pump, which is driven by an electric motor to ensure that the liquid hydrogen flows smoothly under stable pressure and remains at a low temperature to meet the working requirements of the system.

[0035] The one-way flow valve ensures the one-way flow of liquid hydrogen, prevents backflow, and ensures the stability and reliability of the hydrogen supply system.

[0036] Temperature and pressure sensors are used to monitor the state of liquid hydrogen, ensuring it remains within the appropriate temperature and pressure range for subsequent fuel cell electrochemical reactions.

[0037] When the system pressure exceeds the design upper limit, the safety valve automatically releases excess liquid hydrogen to prevent excessive pressure in the pipeline, thereby ensuring the safe operation of the system.

[0038] Liquid hydrogen is vaporized into gaseous hydrogen through a microchannel plate heat exchanger and then stably transported to the hydrogen fuel cell. The microchannel plate heat exchanger increases the heat exchange area through multiple tiny channels, achieving efficient heat transfer and rapid vaporization of liquid hydrogen. At the same time, helium circulates in the heat exchanger, using its high thermal conductivity to take away excess heat in the system, ensuring that the low-temperature components in the system remain within a suitable operating temperature range.

[0039] Helium circulates in the system's cooling loop, exchanges heat through a microchannel plate heat exchanger, removes heat from the system, and then returns to the superconducting motor and fuel cell for cooling, ensuring efficient operation of the superconducting propulsion system.

[0040] Figure 3 The present invention is a schematic diagram of a comprehensive energy management optimization framework of a hydrogen fuel cell superconducting hybrid electric propulsion system based on state machine power allocation and heat balance, including a state machine-based power allocation control loop, a hydrogen-helium heat balance loop, and optimal fuel demand calculation.

[0041] According to the flight profile parameters of the megawatt-class regional aircraft, the flight status of the aircraft during take-off, climb, cruise and landing stages is evaluated, and the power and energy requirements for each stage are calculated.

[0042] The parameters such as the mass, power, efficiency and operating temperature of the hydrogen fuel cell, lithium battery, superconducting motor and cryogenic inverter of the hydrogen fuel cell superconducting hybrid electric propulsion system need to be precisely set through design to ensure that the system achieves optimal efficiency during operation.

[0043] The hydrogen fuel cell superconducting hybrid electric propulsion system dynamically adjusts the power output of fuel cells and lithium batteries through a state machine algorithm to ensure that the system achieves optimal energy efficiency in different flight phases.

[0044] Table 1 shows the system parameters involved parameter symbol unit Hydrogen fuel cell output power <![CDATA[P fc ]]> kW Hydrogen fuel cell power upper limit <![CDATA[P fc,max ]]> kW Hydrogen fuel cell power lower limit <![CDATA[P fc,min ]]> kW Hydrogen fuel cell optimal power <![CDATA[P fc,opt ]]> kW Lithium battery output power <![CDATA[P bat ]]> kW Lithium battery charging power <![CDATA[P bat,min ]]> kW Lithium battery state of charge SOC ％ Lithium battery state of charge upper limit <![CDATA[SOC min ]]> ％ Lithium battery charge state lower limit <![CDATA[SOC max ]]> ％ Hybrid electric propulsion system power requirement <![CDATA[P req ]]> kW

[0045] The state machine control strategy is based on the aircraft battery state of charge (SOC) and power demand (P req ) as input and the optimal power of the fuel cell as output.

[0046] The state machine control strategy is divided into three states according to different SOC ranges: SOC>SOC max , SOC min <SOC<SOC max and SOC <SOC min , and according to the system power demand P at the current moment req , fuel cell power P fc , determine the output power of the fuel cell at the next moment, which is divided into the following cases:

[0047] (1) When the battery state of charge is higher than the upper limit, if the power demand is less than the minimum power of the fuel cell, the fuel cell will operate at the minimum power; if the power demand is between the minimum power and the maximum power, the fuel cell output will be equal to the required power; when the power demand is greater than the maximum output power of the fuel cell, the fuel cell will operate at the maximum power.

[0048] (2) When the battery state of charge is within the normal range, if the power demand is less than the optimal output power, the fuel cell will operate at the optimal power; when the power demand is between the optimal power and the maximum power, the output power is equal to the required power; when the power demand exceeds the maximum power, the fuel cell will operate at the maximum power.

[0049] (3) When the battery state of charge is lower than the lower limit, if the power demand is less than the minimum power of the fuel cell, the fuel cell operates at the minimum power; if the power demand exceeds the maximum power, the system starts the hybrid mode, and the fuel cell and lithium battery jointly supply power to meet the power demand.

[0050] The fuel cell power P output by the state machine control strategy fc , combined with the fuel cell efficiency (η fc )、output voltage(U fc ) and other parameters to calculate the current, and then adjust the power through the limiting link to meet the actual needs of the load.

[0051] The state machine control strategy ensures the efficient operation of the entire system under different load conditions by adjusting the output power and current of the fuel cell, and ensures that the system can flexibly switch to hybrid power mode when the battery is low to provide sufficient power output to ensure the power requirements of the aircraft.

[0052] The hydrogen fuel cell superconducting hybrid electric propulsion system calculates the power and heat output of components such as hydrogen fuel cells, batteries, superconducting motors and cryogenic inverters at each discrete moment, and dynamically adjusts the helium cooling flow based on the principle of heat balance to ensure that the heat exchanger temperature is always maintained within a safe range, thereby ensuring stable operation of the system.

[0053] When the temperature of components in the cryogenic cooling loop exceeds the preset range, the system will automatically adjust the helium flow rate to restore and maintain the system thermal balance, ensuring that all key components always operate at optimal temperature conditions.

[0054] The system accurately calculates the hydrogen demand of hydrogen fuel cells to ensure that the fuel supply closely matches the actual power demand. By dynamically adjusting the liquid hydrogen flow rate and the operating status of the heat exchanger, the system ensures the stability and efficiency of the hydrogen supply and ensures the continuous and efficient operation of the system.

[0055] The system intelligently adjusts the hydrogen flow based on real-time acquisition of key parameters such as component temperature, energy consumption, and load changes, thereby achieving optimal energy configuration, maximizing fuel utilization efficiency, and maintaining smooth and efficient operation of the system.

[0056] The above embodiments are only used to clearly illustrate the technology and features of the present invention so that ordinary technicians in the field can easily understand and implement them, and are not used to limit the present invention. Any modifications, equivalent substitutions and improvements that do not depart from the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The present invention is a hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling suitable for megawatt-class branch aircraft, characterized in that: It mainly includes core components such as liquid hydrogen storage tanks, hydrogen-helium heat exchangers, hydrogen fuel cells, lithium batteries, inverters, superconducting motors and propellers; the liquid hydrogen storage tank vaporizes liquid hydrogen through a microchannel plate hydrogen-helium heat exchanger, and supplies hydrogen stably to the hydrogen fuel cell to generate electricity; helium is used in the cryogenic cooling circuit to cool key components such as superconducting motors, cryogenic inverters, superconducting cables and hydrogen fuel cells; hydrogen fuel cells and lithium batteries work together to provide power for the superconducting propulsion system, and the parameters of each component are reasonably supervised, allocated and scheduled through an integrated energy management controller to meet the efficient power extraction needs of megawatt-class regional aircraft.

2. A hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling as claimed in claim 1, characterized in that: The hydrogen-helium heat exchanger adopts a microchannel plate heat exchanger, which is used to vaporize the liquid hydrogen flowing out of the liquid hydrogen storage tank. The vaporized hydrogen is stably transported to the anode of the hydrogen fuel cell for power generation, thereby achieving a continuous and stable hydrogen supply to the hydrogen fuel cell and ensuring the continuity of power output.

3. A hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling as claimed in claim 1, characterized in that: The helium gas flowing out of the microchannel plate hydrogen-helium heat exchanger enters the cryogenic cooling circuit to efficiently cool components such as superconducting motors, cryogenic inverters, superconducting cables and hydrogen fuel cells, ensuring that the helium cryogenic circuit components operate stably within the operating temperature range, thereby improving the overall operating stability and reliability of the system.

4. A hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen-helium heat exchange cooling as claimed in claim 1, characterized in that: The hydrogen fuel cell and lithium battery work together to provide electrical energy for the superconducting propulsion system on both sides of the fuselage. The integrated energy management controller adopts a state machine strategy to dynamically adjust the output power of the fuel cell and lithium battery according to the power demand and battery charge state of different flight phases, thereby realizing effective monitoring and optimal allocation of the working parameters of each component, ensuring that the system achieves optimal thermal balance and power output in different flight phases such as take-off, cruising and landing, and meeting the efficient power extraction needs of megawatt-class regional aircraft.

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