A Hybrid Energy Refrigeration Integration Solution Based on a Superconducting Generator

Abstract

The present invention belongs to the field of aerospace electric propulsion technology and is a hybrid energy refrigeration integration solution based on a superconducting generator applicable to high-power aerospace distributed electric propulsion. It includes an aeroengine, a superconducting generator, a liquid hydrogen storage tank, a hydrogen fuel cell, a storage battery, an electric motor, a fan, and control units for each component. The liquid hydrogen storage tank provides liquid hydrogen for cooling the superconducting generator component. After vaporization, the obtained hydrogen gas supplies anode fuel to the hydrogen fuel cell to generate electric energy, realizing the on-board cooling of the superconducting generator and the reuse of hydrogen energy. The superconducting generator, hydrogen fuel cell, and storage battery generate electricity to supply the distributed electric motor. The hybrid power system controller reasonably allocates, schedules, and optimizes the parameters of each component through a rule-based power tracking control energy management strategy. This hybrid energy refrigeration integration solution based on a superconducting generator can effectively reduce fuel consumption, increase the system power density, and improve energy utilization efficiency, and can meet the high-power and high-efficiency power extraction requirements of high-power aerospace distributed electric propulsion.

Description

Technical Field

[0001] The present invention belongs to the technical field of aerospace electric propulsion, and more specifically, relates to an integrated refrigeration solution for hybrid power and energy based on a superconducting generator. Background Art

[0002] The world today is facing severe problems such as the depletion of fossil fuels and the aggravation of environmental pollution. As one of the fundamental causes of the energy crisis, the aviation industry has listed energy conservation, emission reduction, cleanliness, and high efficiency as its primary development goals. The emergence of more electric / all-electric aircraft has become an important measure to solve the current problems, and the technological progress and innovation of its power system are necessary guarantees for improving fuel utilization efficiency and reducing emissions. Hybrid propulsion technology combines the advantages of multiple power sources and energy sources and has become a viable and promising option for more electric / all-electric aircraft.

[0003] To achieve high-power hybrid propulsion technology, an airborne generator with high power density and high energy conversion efficiency is required. The power density of traditional motors is usually between 0.5 kW / kg and 2.5 kW / kg, and the weight of motors with MW-level power requirements is close to one ton, which is not suitable for high-power aerospace electric propulsion. High-power superconducting generators use superconducting materials with high current density and low loss, significantly reducing volume and weight, and their power density can reach 10 kW / kg. However, due to the strict cryogenic working environment required for superconducting materials, cryogenic refrigerators using working fluids such as liquid helium and liquid nitrogen are generally used at the current stage. The complex structure and large mass and volume of cryogenic refrigeration devices limit the practical application of superconducting generators.

[0004] To achieve high-power hybrid propulsion technology, multiple power sources and energy sources are required. Traditional aviation engines need to consume a large amount of fuel to achieve high-power output, and at the same time, they will release a large amount of air pollutants such as CO2 and NO X etc., and the gas vaporized from the cooling working fluid of superconducting generators cannot be recycled. The traditional electric propulsion system consists of a single high-power motor and a large-diameter fan, with a single configuration method and low control flexibility, posing great challenges to the aerodynamic design and integrated control of high-power electric propulsion aircraft.

[0005] Therefore, in view of the above problems faced by high-power aerospace electric propulsion systems, this invention patent uses an airborne liquid hydrogen storage tank to cool the superconducting generator, uses the hydrogen generated after liquid hydrogen vaporization as the fuel for a hydrogen fuel cell, dynamically allocates the output power of the superconducting generator, hydrogen fuel cell, and battery through a hybrid power system controller, and adopts a distributed electric propulsion system to improve propulsion efficiency and ensure high-power electricity demand, significantly improving energy utilization efficiency and reducing fuel consumption. Summary of the Invention

[0006] To solve the problems of high fuel consumption and low power density in traditional aviation propulsion systems, and at the same time overcome the difficulties of ineffective utilization of cooling and energy of airborne generators, the present invention provides an integrated hybrid energy refrigeration solution based on superconducting generators. The cooling of superconducting generators is achieved through airborne liquid hydrogen storage tanks, and hydrogen fuel cells recycle the hydrogen generated by cooling vaporization to improve energy utilization efficiency. The superconducting generators, hydrogen fuel cells and storage batteries jointly supply power to a distributed electric propulsion system composed of multiple smaller power motors and small-diameter fans. The system energy conversion efficiency and aircraft propulsion efficiency are improved through component controllers and hybrid power system controllers.

[0007] To achieve the above object, the present invention is an integrated hybrid energy refrigeration solution based on superconducting generators applicable to high-power aviation distributed electric propulsion, which is characterized by mainly including an aeroengine, a superconducting generator, a liquid hydrogen storage tank, a hydrogen fuel cell, a storage battery, a motor, a fan and each component control unit; the liquid hydrogen storage tank, the superconducting generator and the hydrogen fuel cell can achieve the cooling of airborne motors and the reuse of hydrogen energy. The superconducting generator, the hydrogen fuel cell and the storage battery can all generate electricity to supply multiple motors arranged distributively. The hybrid power system controller and the motor controller reasonably allocate, schedule and optimize the parameters of each component to meet the power extraction requirements of high-power aviation electric propulsion.

[0008] The liquid hydrogen storage tank supplies the cooling working medium liquid hydrogen to the superconducting generator through its own pressurization system. After the liquid hydrogen cools components such as the superconducting generator, cable ducts and power conversion units and vaporizes into gaseous hydrogen, the gaseous hydrogen flows to the anode of the hydrogen fuel cell after being heated to the ambient temperature by a heater, and chemically reacts with the cathode air to generate electric energy, realizing the cooling of the airborne superconducting generator and the reuse of hydrogen energy.

[0009] The aeroengine-superconducting generator, hydrogen fuel cell and storage battery can all generate electricity to supply the motors. The motor controller dynamically controls multiple small-power motors arranged distributively according to the real-time propulsion requirements. The hybrid power system controller reasonably distributes multiple energy sources and power sources through the CAN bus and the aircraft integrated controller to meet the power requirements of the aircraft under different flight attitudes and missions.

[0010] The hybrid power system controller dynamically allocates the output powers of the aeroengine-superconducting generator, the storage battery and the hydrogen fuel cell through an energy management strategy, and adopts an energy management algorithm based on power tracking control to complete the switching of the working modes of the aeroengine and the storage battery according to information such as the real-time required power of the system and the operating parameters of components, so as to minimize fuel consumption, pollutant emissions and maximize energy conversion efficiency under different flight missions.

[0011] Preferably, the liquid hydrogen storage tank supplies 20K liquid hydrogen for low-temperature cooling of components such as superconducting generators, cable pipelines, and power conversion devices, and can effectively cool the airborne superconducting generator and cryogenic pipelines without other refrigeration equipment.

[0012] Preferably, the hydrogen fuel cell obtains vaporized hydrogen gas from the rear end of the component to be cooled, and after heat treatment, uses it as the anode of the chemical reaction to react with cathode oxygen to generate electric energy.

[0013] Preferably, the battery, superconducting generator, and hydrogen fuel cell can all generate electric energy to supply the distributed propulsion system, and the hybrid power system controller and motor controller reasonably allocate and schedule to meet different power extraction requirements of the aircraft.

[0014] Preferably, the hybrid power system controller dynamically allocates the output powers of the aero-engine - superconducting generator, battery, and hydrogen fuel cell through an energy management strategy based on power tracking control, achieving minimum fuel consumption and maximum energy conversion efficiency under different flight missions.

[0015] Generally speaking, compared with the existing power propulsion system, the hybrid power energy refrigeration integration solution based on superconducting generators applicable to high-power aviation distributed electric propulsion of the present invention can achieve the following effective gains:

[0016] 1. The hybrid power energy refrigeration integration solution based on superconducting generators provided by the present invention realizes the airborne cooling of superconducting generators and the effective utilization of hydrogen energy, improving the power density and energy utilization rate of the hybrid power system.

[0017] 2. The hybrid power energy refrigeration integration solution based on superconducting generators provided by the present invention can supply power to the distributed electric propulsion system with multiple power sources and energy sources. The hybrid power system controller and motor controller effectively allocate and schedule through the energy management strategy to meet the power extraction requirements of high-power aircraft. Brief Description of the Drawings

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

[0019] Figure 1 It is a schematic diagram of the architecture of the hybrid power energy refrigeration integration solution based on superconducting generators provided by the embodiment;

[0020] Figure 2 It is a schematic diagram of the principle of airborne superconducting generator cooling and hydrogen energy recovery and utilization based on a liquid hydrogen storage tank provided by the embodiment;

[0021] Figure 3It is a schematic diagram of the bus interaction relationship between the hybrid system controller provided by the embodiment and each component control unit;

[0022] Figure 4 It is an energy management strategy for an integrated hybrid power source refrigeration system based on power tracking control provided by the embodiment; Specific implementation manners

[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to 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 used 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.

[0024] Figure 1 It is a schematic diagram of the architecture of an integrated hybrid power source refrigeration system based on a superconducting generator applicable to high-power aviation distributed propulsion, including basic components such as an aeroengine, a superconducting generator, a liquid hydrogen storage tank, a hydrogen fuel cell, a storage battery, an electric motor and a fan, and control components such as an engine control unit (ECU), a fuel cell controller (FCU), a battery management system (BMS), an aircraft integrated controller, a motor controller (MCU) and a hybrid system controller (HCU).

[0025] The aeroengine and the superconducting generator, and the electric motor and the fan are mechanically connected. By utilizing the characteristic that the electric motor has an approximate independence from the relative scale, a high-power electric motor and a large-diameter fan system are decomposed into a combination of multiple smaller-power electric motors and smaller-diameter fans, so as to realize distributed electric propulsion and thus improve the performance of the power system and the aerodynamic efficiency of the aircraft.

[0026] The liquid hydrogen storage tank, the superconducting generator and the hydrogen fuel cell are connected in a pipeline form. The liquid hydrogen vaporizes into gaseous hydrogen after flowing through the heat exchanger of the superconducting generator, and the latter flows to the anode of the hydrogen fuel cell through a controlled heater to generate electricity.

[0027] The superconducting generator, the hydrogen fuel cell, the storage battery and the electric motor are all connected in an electrical form, and the effective conversion and utilization of electric energy are completed through the integrated controller.

[0028] Control units such as the ECU, the FCU, the BMS, the MCU and the HCU are communicatively connected through a CAN bus, and the component parameters are interacted in real time to achieve the overall control of the hybrid system.

[0029] Figure 2It is a schematic diagram of the cooling of an airborne superconducting generator and the recycling principle of hydrogen energy based on a liquid hydrogen storage tank provided by the embodiment, mainly including a liquid hydrogen storage tank, a superconducting generator heat exchanger, a cable conduit, a power conversion unit heat exchanger, a controlled heater, and a hydrogen fuel cell.

[0030] The liquid hydrogen storage tank transports liquid hydrogen LH2 in the form of a pipeline to cooling components such as the superconducting generator heat exchanger and the cable conduit through its own pressurization system, and a certain value of parasitic heat consumption will be generated during the transfer process.

[0031] After the components are cooled, the 20K liquid hydrogen LH2 vaporizes into 30K gaseous hydrogen GH2. Due to the heat generated by the power conversion unit itself, the temperature can rise to 50K after flowing through the power conversion unit heat exchanger, and there is also parasitic heat consumption in this process.

[0032] The controlled heater heats the mixture of liquid hydrogen, gaseous hydrogen, etc. to the ambient temperature, and the generated hydrogen gas flows to the anode of the hydrogen fuel cell and reacts with the cathode to generate electric energy.

[0033] Figure 3 It is a schematic diagram of the bus interaction relationship between the hybrid power system controller and each component control unit provided by the embodiment, including control units such as the hybrid power system controller (HCU), the engine control unit (ECU), the fuel cell controller (FCU), the battery management system (BMS), the aircraft integrated controller, the motor controller (MCU), and the indication system.

[0034] The ECU, FCU, BMS, MCU, and aircraft integrated controller feedback the operating status of the components to the HCU through the CAN bus. The HCU completes the allocation and scheduling of the three energy sources through its own energy management control strategy in combination with the overall demand power of the system, and the real-time hybrid power system parameters can be displayed through the indication system.

[0035] The aeroengine is mechanically connected to the superconducting generator. The two are the main power sources of the hybrid power system. The internal energy of the fuel is converted into mechanical energy by combustion to drive the superconducting generator. The engine control unit ECU is connected to the hybrid power system controller HCU through the CAN bus to monitor the engine speed, torque, and working mode in real time.

[0036] The hydrogen fuel cell realizes interactive control with the hybrid power system controller HCU through the controller FCU. The FCU monitors parameters such as the voltage, current, working temperature, and gas flow of the hydrogen fuel cell in real time and feeds them back to the HCU. The HCU sends mode commands to the FCU according to the overall demand power of the hybrid power system and the working status of other power sources and energy sources.

[0037] The battery selects lithium batteries with high power density and high energy density, generates direct current, and converts it into alternating current through the DC / AC converter in the integrated controller to supply the motor, which is the auxiliary power source of the system.

[0038] The battery can perform multiple charge and discharge operations to achieve power peak shaving and valley filling for the system. When the power demand of the hybrid system is small, the battery power is low, and the aero-engine is near the optimal fuel consumption operating point, the excess electrical energy can be used to charge the battery to prevent the battery power from being sufficient for the aircraft to land safely in the event of an aero-engine failure mode.

[0039] The battery converts its own high-voltage direct current into low-voltage direct current through a DC / DC converter and supplies it to the aircraft's low-voltage power supply system.

[0040] The motor controller MCU feeds back the actual speeds, torques, and operating modes of multiple small motors to the hybrid system controller HCU through the CAN bus. The HCU sends mode commands to the MCU in combination with the actual required propulsion power to achieve distributed control of multiple small propulsion systems.

[0041] The hybrid system controller HCU adjusts the throttle lever position according to the integrated controller instruction, calculates the power distribution scheme of the aero-engine, hydrogen fuel cell, battery, and motor, and displays the system real-time parameters on the indication system.

[0042] Figure 4 It is an energy management strategy for a hybrid energy refrigeration integrated system based on power tracking control provided by the embodiment. The aero-engine - superconducting generator, hydrogen fuel cell, and battery can all generate electrical energy to supply the distributed electric propulsion system. The hybrid system controller HCU judges the overall power demand and operating mode of the aircraft, and adopts an energy management strategy based on power tracking control to allocate and schedule the three energy sources to meet the electrical power requirements of the aircraft under different flight attitudes and missions. [[ID= 18]]

[0043] Table 1 shows the system parameters involved

[0044] Parameter Unit Engine output power <![CDATA[P eng > kW Upper limit value of engine power <![CDATA[P up_eng > kW Lower limit value of generator power <![CDATA[P low_eng > kW Output power of hydrogen fuel cell <![CDATA[P fc > kW Output power of battery <![CDATA[P bat > kW State of charge of battery SOC ％ Upper limit value of state of charge of battery <![CDATA[SOC up > ％ Lower limit value of state of charge of battery <![CDATA[SOC low > ％ Demand power of hybrid system <![CDATA[P req > kW

[0045] Obtain control information such as flight speed, flight altitude, and flight time according to the flight mission profile line of the aircraft and input it into the flight controller.

[0046] Assume that the cooling medium in the liquid hydrogen storage tank is sufficient to complete the cooling of the superconducting generator under the flight mission and generate enough hydrogen to supply the hydrogen fuel cell to generate electrical energy.

[0047] The power level of the hybrid system is in the megawatt range. The engine is the main power source, and the battery and hydrogen fuel cell are auxiliary power sources, where the power rating of the hydrogen fuel cell is in the hundred-kilowatt range.

[0048] Calculate the total required power P of the hybrid system req , obtain the operating parameters of the main power source and energy source of the system, and the output power P of the aero-engine eng , the output power P of the battery bat and the output power P of the hydrogen fuel cell fc .

[0049] According to the system required power P req and the upper limit value P of the engine power up_eng , the lower limit value P low_eng , the numerical relationship is divided into the following situations:

[0050] (1) When P req >P up_eng , the hydrogen fuel cell discharges first, and then judge whether P req >P up_eng +P fc . If it holds, continue to judge whether the state of charge of the battery SOC > SOC low . If the formula holds, control the battery to discharge. If it does not hold, adjust the engine operating point to increase the output power of the engine. At this time, the fuel consumption continues to increase; if P req >P up_eng +P fc the formula does not hold, directly reduce the output power of the engine appropriately.

[0051] (2) When P low_eng <P req <P up_eng , the hydrogen fuel cell discharges first, and then judge whether P low_eng <P req -P fc <P up_eng . If the formula holds, continue to judge whether the state of charge of the battery SOC < SOC up . If the formula holds, charge the battery with the excess electric energy generated by the engine. If it does not hold, discharge the battery and reduce the output power of the engine at the same time to ensure that it operates at the optimal fuel consumption operating point and reduce the fuel consumption; if P low_eng <P req -P fc <P up_eng the formula does not hold, directly adjust the engine operating point.

[0052] (3) When P req <P low_eng , the system required power is small. Control the hydrogen fuel cell to discharge first, and then judge whether SOC > SOC low, if the formula holds, control the battery to discharge, and at the same time, the engine control unit shuts down the engine. The power generated by the battery and the fuel cell can meet the required power. If the formula does not hold, the engine continues to operate, and the excess electrical energy is used to charge the battery to achieve the charge-discharge balance of the state of charge (SOC) of the battery.

[0053] The hybrid system controller repeats the above process until all sampling points within the flight mission time are covered, and the output powers of the engine, the battery, and the hydrogen fuel cell are allocated in real time through an energy management strategy based on power tracking control.

[0054] The above embodiments are only used to clearly illustrate the technology and features of the present invention, so that those of ordinary skill in the art can easily understand and implement them, and are not used to limit the present invention. Any modifications, equivalent replacements, and improvements made without departing from the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hybrid energy refrigeration integrated device based on a superconducting generator, characterized in that, It mainly includes an aeroengine, a superconducting generator, a liquid hydrogen storage tank, a hydrogen fuel cell, a storage battery, an electric motor, a fan and control units for each component; the liquid hydrogen storage tank, the superconducting generator and the hydrogen fuel cell can realize the cooling of the airborne generator and the reuse of hydrogen energy. The superconducting generator, the hydrogen fuel cell and the storage battery can all generate electricity to supply multiple motors arranged in a distributed manner. Through the hybrid power system controller and the motor controller, the parameters of each component are reasonably allocated, scheduled and optimized to meet the power extraction requirements of high-power aircraft electric propulsion; The liquid hydrogen storage tank supplies the cooling working medium liquid hydrogen to the superconducting generator through its own pressurization system. After the liquid hydrogen cools the superconducting generator, the cable conduit and the power conversion unit, it vaporizes into gaseous hydrogen. The gaseous hydrogen flows to the anode of the hydrogen fuel cell after being heated to the ambient temperature by the heater, and reacts chemically with the cathode air to generate electric energy, thus realizing the cooling of the airborne superconducting generator and the reuse of hydrogen energy; The hybrid power system controller dynamically allocates the output powers of the aeroengine-superconducting generator, the storage battery and the hydrogen fuel cell through an energy management strategy, and completes the switching of the working modes of the aeroengine and the storage battery by using an energy management algorithm based on power tracking control according to the real-time required power of the system and the main parameters of the components, so as to minimize fuel consumption, pollutant emissions and maximize energy conversion efficiency under different flight missions; The aeroengine-superconducting generator, the hydrogen fuel cell and the storage battery can all generate electricity to supply the motors. The motor controller dynamically controls the multiple small-power motors arranged in a distributed manner according to the real-time propulsion requirements. The hybrid power system controller completes the reasonable allocation of multiple energy sources and power sources through the CAN bus and the aircraft integrated controller to meet the power requirements of the aircraft under different flight attitudes and missions; The working process of the hybrid power system controller includes: Calculate the total required power P of the hybrid power system req , obtain the operating parameters of the main power source and energy source of the system, the output power P of the aero-engine eng , the output power P of the battery bat and the output power P of the hydrogen fuel cell fc ; According to the total system required power P req and the upper limit value P of the aero-engine power up_eng , lower limit value P low_eng The numerical relationships are divided into the following cases: (1) When P req > P up_eng , the hydrogen fuel cell discharges first, and then it is judged whether P req > P up_eng + P fc . If it holds, it continues to judge whether the state of charge of the battery SOC > the lower limit of the state of charge SOC low . If the formula holds, the battery is controlled to discharge. If it does not hold, the operating point of the aero-engine is adjusted to increase the output power of the aero-engine. At this time, the fuel consumption continues to increase; if P req > P up_eng + P fc the formula does not hold, the output power of the aero-engine is directly and appropriately reduced; (2) When P low_eng <P req <P up_eng When, the hydrogen fuel cell discharges first, and then determines P low_eng <P req -P fc <P up_eng . If the formula holds, continue to determine whether the state of charge (SOC) of the battery is less than the upper limit value of the state of charge SOC up . If the formula holds, charge the battery with the excess electrical energy generated by the aero-engine. If it does not hold, discharge the battery and at the same time reduce the output power of the aero-engine to ensure that it operates at the optimal fuel consumption operating point and reduce fuel consumption; If P low_eng <P req -P fc <P up_eng The formula does not hold, then directly adjust the operating point of the aero-engine; (3) When P req <P low_eng At this time, the system demand power is small. Control the hydrogen fuel cell to discharge first, and then judge whether SOC > SOC low . If the formula holds, control the battery to discharge. At the same time, the aero-engine control unit shuts down the aero-engine. The power generated by the battery and the hydrogen fuel cell can meet the demand power. If the formula does not hold, the aero-engine continues to operate and charges the battery with the excess electrical energy to achieve the charge and discharge balance of the battery state of charge SOC; The hybrid power system controller repeats the above process until all sampling points within the flight mission time are covered, and dynamically allocates the output powers of the aeroengine, the storage battery and the hydrogen fuel cell through an energy management strategy based on power tracking control.

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