RU2768988C1 - Aviation integrated electric power plant - Google Patents

Abstract

FIELD: aviation technology.

SUBSTANCE: aviation integrated electric power plant contains a battery pack made using superconducting materials with the possibility of cryocooling a switchgear, connecting cables, at least one engine, a cryo-system with at least one cryogenic cooling circuit for components of the installation made using superconducting materials interconnected in a certain way.

EFFECT: total weight of the aviation integrated electric power plant is reduced and stable operation of the plant is achieved by reducing the thermal load on the cryogenic system of the plant and eliminating unused cryogenic pumps.

8 cl, 1 dwg

Description

The field of technology.

SUBSTANCE: invention relates to placement of elements of power plants on an aircraft, in particular, devices for circulation of a cryogenic medium with forced circulation, using pipelines for cooling elements of high-temperature superconducting components of installations.

The level of technology.

In aviation technology, the most stringent requirements for power density, efficiency and safety are imposed on power plants. Until recently, and before the advent of materials and products based on the effect of high-temperature superconductivity, it was fundamentally impossible to create electric drives for high-power propulsion devices using traditional technologies, especially for aviation.

Actual for these tasks, electric drives, designed according to the most advanced technologies and methods, without the use of high-temperature superconductors (hereinafter referred to as HTSC), have compromise characteristics in terms of efficiency and power density. However, conventional power transmission and distribution systems, without the use of HTSC, are several times larger than solutions based on superconductors and cryogenic technologies in terms of weight and size.

For a long flight of a passenger or transport aircraft (hereinafter LA), in order to improve technical characteristics, hybrid power plants (hereinafter HPU) can be used, in which the electric motor is powered by electric generators driven, for example, by internal combustion engines. For a long flight of an aircraft of a class smaller than for passenger and transport transportation, all-electric power plants (EPS) are already used, in which the primary energy source is an energy storage system (battery, battery pack).

Electric power plants are universal, the primary source of energy in them can be either from an electric generator with a drive, while an internal combustion engine can be used as a drive, or from an energy storage system (batteries, battery pack). At the same time, in each of the indicated power plants for a passenger or transport aircraft, it is possible to achieve a reduction in weight and size characteristics and an increase in efficiency if the windings of the stator, rotor of electric motors, electric generator, cables of the power plant are made using HTSC conductors that operate at cryogenic temperatures.

The effect of superconductivity of all currently known high-temperature superconductors lies in the cryogenic range (for example, below 77°K), therefore, a cooling apparatus is required for the operation of devices and devices based on HTSC.

So from the prior art, a cryoprovision system is known according to patent RU No. 2616147 (F25B 45/00, 04/12/2017), designed to introduce and remove refrigerant in high-temperature superconducting devices. At the same time, the system contains an additional drainage line with an installed valve, a nitrogen vapor heater and a vacuum pump, a system for supplying gaseous helium to the cryostat and bubbling it through the cryogenic liquid in the tank. The invention is intended to increase the efficiency and reliability of maintaining a given level of cryogenic liquid temperature in HTSC windings of electrical machines.

The disadvantages of this system is the use of a cryocooler to compensate for heat losses, which significantly increases the mass of the cryosystem, while having a limited cooling capacity. Based on the schematic representation of the cryosystem, its operation requires a height difference between the cryosystem and the cooled object, which cannot always be realized when using a cryosystem to cool the engine on a vehicle. Thus, this cryoprovision system cannot be used on board an aircraft due to the high mass of the system and the difficulty in ensuring safe autonomous operation. Also, the given device is designed for cooling only one consumer, and even when a second circulation pump is installed, the use of a cryo-cooler to compensate for heat losses does not allow one to control the depth of subcooling of each consumer independently, since the cryo-cooler supercools the entire refrigerant supply in the tank.

Also known from the prior art are power plants using cryogenic cooling to achieve high specific power in aviation technology.

From patent document US 2019009917 (B60L 0/10, 01/10/2019) a drive system and a method for providing kinetic energy to an aircraft propulsion device are known. The drive system is made in the form of a series hybrid system, which contains an electric motor to drive the propulsion device, a generator to provide electric power to the electric motor, and an internal combustion engine to ensure the operation of the generator. The design of the generator has elements that use the properties of superconductivity during operation. Hydrogen is used as a coolant for the generator. Once the hydrogen in the area surrounding the generator exceeds a predetermined temperature, the hydrogen is extracted from the generator in a gaseous state and fed to a device that treats the hydrogen in such a way that energy is provided that can be used in the drive system. The device may be a fuel cell and/or an internal combustion engine made, for example, in the form of a hydrogen turbine. The system and method of said patent achieves an optimal power-to-weight ratio for a commercial vehicle hybrid drive system.

The disadvantage of this solution is that the drive system implies a one-way supply of refrigerant from the reservoir to the superconducting component, followed by evaporation. The coolant (part of the coolant can be transferred in a gaseous state) from the generator is transferred to the fuel cell, from where the reaction product in the fuel (deionized water) element is transferred to the electric motor for cooling. However, since the required cooling capacity can vary over time, and because the drive system requires that the supply of refrigerant is sufficient at all times to function reliably, it is necessary either to create a complex feedback system that regulates the supply of refrigerant, or to always supply excess refrigerant to shut off heat gain, resulting in inefficient use of the refrigerant. Also, in the description of the solution, no attention is paid to how to cool several superconducting consumer components located in different parts of the vehicle.

The closest to the proposed invention is the technical solution according to the patent RU No. 2730734 (B60K 6/22.25.08.2020). According to this technical solution, the hybrid power plant includes a primary-to-mechanical energy converter (PPEM) with a primary energy source (PIE), where the converter can be an internal combustion engine (ICE), a gas turbine engine (GTE), a turboprop engine (TVD), a turbojet engine (TRD), etc. As a PIE, for example, chemical, nuclear fuel, etc. are used. The GSU also contains an electric power generator, one or more electric motors, connecting cables, alternative energy sources, an energy storage system, an energy distribution unit (distribution device), controllers and converting devices. It additionally contains blocks for cryocooling of power plant connecting cables made using superconducting material, cryocooling blocks for converter device valves, cryocooling blocks for electric generator and electric motors, which contain armature and excitation windings made of superconducting material. Cryo-cooling units for connecting cables of the power plant, valves of converter devices, as well as armature and excitation windings of the electric generator and electric motors are combined into a single cryogenic supply system. Due to this, an increase in specific power, an improvement in weight and size indicators, and an increase in efficiency are achieved.

However, within the framework of providing cryogenic cooling in this HPS, each component of the power plant is cooled by a separate cryogenic cooling unit, which creates a large number of cryogenic pipelines and cryopumps.

The cryogenic pipeline is a double vacuum insulated steel pipe, typically having a weight of 2-5 kg/m.p., and a heat input of 2-10 W/m.p. Each cryogenically cooled device has two pipelines - one of the cryogenic medium is supplied to the device, the second is returned to the cryosystem. Under the condition that all devices are cooled from a single cryogenic system, in aircraft conditions, the engines can be located at a distance of 15-30 meters from the cryosystem. Thus, even with only two cryogenically cooled electric motors, the weight of the pipelines can be from 120 to 600 kg, and create an additional heat influx into the cryogenic volume from 120 to 1200 W. Cryo-cooled cables and other devices create the same thermal load and additional weight. In addition, each cryogenic circuit requires the installation of an independent pumping apparatus, which creates an additional 500 W of heat gain. In general, these shortcomings leave the technical solution experimental (research), difficult to implement in real aircraft operating conditions.

Disclosure of the essence of the invention.

It is important to note that some components (devices) that use superconductivity during operation (in Fig. 1 - a diagram of an aviation integrated electric power plant, they are conventionally indicated by darker rectangles and are united by the term: "cryogenic elements"), both hybrid power plants and electric power plants installations can only work in interconnection, and failure, in particular, the loss of cryogenic cooling of one device will lead to the inability to use the second and all functionally interconnected. So, for example, an interconnected pair of installation components is formed by an electric motor and an HTS cable that feeds it, which can only work if each other is functioning properly. If, for example, the cryogenic medium supply pump of one of the devices fails, the operation of the second one will automatically become impossible, even if its cryogenic medium supply pump is in good order.

Thus, when combined in a cryogenic circuit, for example, an electric motor and a HTSC cable feeding it, the required number of cryogenic pipelines and cryogenic pumps is reduced, the heat influx through cryogenic lines is halved and, as a result, the risk of system failure due to the failure of the cryogenic pump is halved.

Combining can be performed by connecting the cryogenic medium supply line from the cryosystem to the electric motor, connecting the cryogenic medium return line from the electric motor to the cryogenic medium supply line to the HTSC cable, and connecting the HTSC cable return line to the cryosystem. Similarly, it is possible to combine the lines of switching and protective devices (current-limiting and distribution devices) and, if a generator is used in the power plant, it is possible to combine the lines of the generator and the HTSC power cable from the generator.

The technical result of the invention is to reduce the total weight of the aviation integrated electric power plant and achieve stable operation of the plant by reducing the thermal load on the cryogenic system of the plant and eliminating unused cryogenic pumps.

This technical result is achieved due to the fact that an aviation integrated electric power plant containing the following components: at least one engine, connecting cables, a switchgear made using superconducting materials with the possibility of cryocooling, an energy storage system and a cryosystem with at least at least one cryogenic cooling circuit for interconnected components of the installation, made using superconducting materials.

Also, an aviation integrated electric power plant may include a generator made using superconducting materials with the possibility of cryocooling, connected to a drive from a primary energy converter into mechanical energy and to a rectifier for generated electricity.

In addition, the aircraft integrated electric power plant may include a current limiting device.

Cryogenic cooling circuits in an aircraft integrated electric power plant can be designed to cool the following interconnected plant components made using superconducting materials: "motor and cable", and additionally for "generator and cable" and additionally for "current limiting device and switchgear".

In this case, the cryosystem contains a distribution tank with pumps and at least one outlet and one inlet for cryogenic pipelines according to the number of cryogenic circuits, and the distribution tank of the cryosystem includes at least one pump according to the number of cryogenic circuits.

At the same time, the connection of cryogenic circuits can be made through quick couplings to facilitate the repair and maintenance of the power plant.

Also, the aircraft integrated electric power plant may be configured to use a separate control system for each of the engines, with each of the engines associated with a separate propulsion unit.

Brief description of the drawings.

In FIG. 1 shows a diagram of an aviation integrated electric power plant (AIEU).

Power consumers of the declared aviation integrated electric power plant can be supplied from a generator (1) or from an energy storage system made in the form of a battery pack (7) of electricity without using a generator (1) of electricity in the electric power system.

An example of implementation of the claimed aviation integrated electric power plant is presented (Fig. 1) using at least one generator (1) of electricity driven by the primary drive (2). The primary drive (2) is either an internal combustion engine, or a gas turbine engine, or a turboprop engine, or a turbojet engine. Since a generator (1) is used in the AIEU implementation example, power consumers are supplied from a generator (1) of electricity, the electricity generated from which is rectified by a rectifier (in Fig. 1 it is indicated as a / y) (3) and via a high-temperature superconducting cable (4) is transferred to the switchgear (5).

The rectifier device (3) is a power unit based on diodes, thyristors or other semiconductor devices, which receives alternating current from the generator windings (1) at the input, and produces direct current at the output.

The switchgear (5) may include at least two pairs of contacts for connection to the DC power line, each of which is connected through a contactor that allows the line to be connected or disconnected in a controlled manner.

From the switchgear (5), electricity is distributed to external consumers (8), such as: avionics, navigation, climate systems, etc., as well as through one or more cables (9) to at least one control system ( 10) (in Fig. 1 it is designated as c / y), at least one engine (11), driving at least one propulsor (12).

Also, a battery pack (7) is connected to the switchgear (5) through a current-limiting device (6) (hereinafter referred to as TOU). In this case, the use of TOU (6) is optional.

The control system (10) of the motor (11) includes power semiconductor devices such as IGBTs (insulated gate bipolar transistors) or MOSFETs (metal-oxide-semiconductor, also known as MOSFETs) and Field-Effect-Transistors (electric field controlled transistor) that convert DC input to AC output, where the frequency and phase of the AC depend on the speed setting and the angular position of the motor shaft.

The AIEU provides for the possibility to use a separate control system (10) for each of the engines (11). In this case, each of the engines (11) is connected to a separate propulsion unit (12).

The mover (12) is a unit for converting mechanical energy on the motor shaft into propulsive energy, for example, a propeller or a fan.

To ensure cryogenic cooling of all components (devices), the AIEU includes a cryogenic system (13) filled with a cryogenic medium, which, by means of cryogenic pumps,

(14) is supplied to the AIEU cooling circuits through cryogenic pipelines (15).

In particular, the refrigeration circuits disclosed in accordance with the present invention may consist of:

- generator (1) and HTSC cable (4);

- motor (11) and HTSC cable (9);

current limiting device (6) and switchgear (5).

As a generator (1) and engines (11), a superconducting generator and superconducting electric motors are used.

The generator (1) and motors (11) each contain at least one superconducting component, for example, with armature and excitation windings based on high-temperature superconducting materials of the second generation with high current-carrying capacity, which are in a superconducting state when the components are at an appropriate cryogenic temperature.

Those. to maintain the generator (1) and engines (11) in working order at the cryogenic temperature of the coolant, they are supplied with a cryogenic medium. As the cryogenic medium, for example, liquid hydrogen, nitrogen, neon, helium, and the like can be used.

As a superconducting material for connecting HTSC cables (4,9) of an aviation integrated electric power plant, as well as armature and excitation windings of a generator (1) and engines (11) and TOU (6), a superconducting material is used in the form of long tapes based on HTSC.

The cryosystem (13) contains a distribution tank, at least one cryogenic pump (14) and at least one outlet and inlet for cryogenic pipelines (15) according to the number of cryogenic circuits in the AIEU.

Centrifugal type pumps can be used as cryogenic pumps (14).

Each of the cryogenic pipelines (15) is a double tube made of corrugated stainless steel with vacuum thermal insulation.

At the same time, since the generator (1) and the current-limiting device (6) are optional components (devices) for the implementation of the AIEU function, the number of cryogenic circuits for cooling the interconnected components of the aviation integrated electric power plant can change, as well as the interconnected components can change, for which cooling is carried out and the sequence of combining interconnected components of cryogenic circuits can also be different from that shown in the example of the invention.

Implementation of the invention.

The proposed AIEU (Fig. 1) uses a generator (1) of a synchronous type, two engines (11) of a synchronous type associated with two propellers (12) located on the wings (not shown).

It should be noted that further specific values of currents, pressures and temperatures are given for clarity and in particular embodiments of the invention may differ significantly.

A current of about 1000 A from the generator (1) is supplied via HTSC cables (4) through a rectifier (3) to a switchgear (5), from where it is distributed to external consumers (8) of about 10 A and to motors (11) of about 500 A through HTSC cables (9) and two control systems (10) according to the number of motors (11) to drive the propellers (12).

The cryosystem (13) contains a distribution tank filled with a cryogenic medium (liquid nitrogen), four outlets and inlets in the distribution tank for cryogenic pipelines (15) and four centrifugal cryogenic pumps (14) according to the number of cryogenic circuits in the AIEU.

To maintain the HTSC components (devices) of the AIEU in working condition in the required amount of cryogenic medium, with minimal nitrogen evaporation during AIEU operation, the cryogenic medium from the distribution tank of the cryosystem (13) by means of cryogenic pumps

(14) with a pressure of 0.5 bar is supplied to the AIEU cooling circuits through cryogenic pipelines (15) to the cooling circuits "Generator - HTSC cable"; into two circuits "Motors - HTSC cables" and a circuit "TOU - Switchgear".

Each cryogenically cooled component (device) from the indicated cooling circuits of the AIEU has two pipelines (15) - one of the cryogenic medium is supplied to the component (device), the second is returned to the cryosystem (13).

So in the cooling circuit "Generator - HTSC cable" liquid nitrogen circulates, coming from the cryosystem (13) through the pipeline (15) to the generator (1), then straight-through through the next part of the pipeline (15) into the line of the HTSC cable (4), then straight-through along the next part of the pipeline

(15) liquid nitrogen returns to the cryosystem (13), where it is cooled to a temperature of 72 K.

In the cooling circuits "Motors - HTSC cables", liquid nitrogen circulates, coming from the cryosystem (13) through the corresponding pipelines (15), into the corresponding engines (11), then directly through the following parts of the pipeline (15) into the cable lines (9), then direct-flow through the following parts of the pipeline (15), liquid nitrogen returns to the cryosystem (13), where it is cooled to a temperature of 72 K.

In the cooling circuit "TOU - Switchgear", liquid nitrogen circulates, coming from the cryosystem (13) through the pipeline (15), initially to the TOU (6), then straight through the next part of the pipeline (15) to the switchgear (5), then straight through the next part of the pipeline (15), liquid nitrogen returns to the cryosystem (13), where it is cooled to a temperature of 72 K.

Since all HTSC components (devices) of the AIEU are cooled from a single cryogenic system (13), in aircraft conditions, the engines (11) can be located at a distance of 20 meters from the cryosystem (13), the total weight of pipelines made in accordance with the claimed invention, with a specific weighing 3 kg/m.p., will be 120 kg, and the heat gain at a specific heat gain of 2 W/m.p. - 80 W.

Thus, due to the sequential combination of cryogenic circuits of cryogenic components (devices) included in the aviation integrated electric power plant, a reduction in the total mass of the AIEU and stable operation of the plant is achieved by reducing the thermal load on the cryogenic system and eliminating cryogenic pumps, which are not necessary when implementing the stated solutions.

Claims (8)

1. Aviation integrated electric power plant, containing the following components: a battery pack, made using superconducting materials with the possibility of cryocooling, a switchgear, connecting cables and at least one engine, characterized in that it includes a cryosystem with at least one cryogenic cooling circuit for plant components made using superconducting materials, and the plant components combined into each circuit are functionally interconnected in such a way that failure, in particular, the loss of cryogenic cooling of one device, will lead to the inability to use the second, and, accordingly, all, combined in this circuit. 2. Aircraft integrated electric power plant according to claim 1, characterized in that it contains a generator made using superconducting materials with the possibility of cryocooling, connected to a drive from a primary-to-mechanical energy converter and a rectifier device for rectifying the generated electricity. 3. Aviation integrated electric power plant according to claim 1 or 2, characterized in that it contains a current-limiting device. 4. Aviation integrated electric power plant according to claim 1, characterized in that the cryogenic cooling circuits can be made to cool the following interconnected components of the installation, made using superconducting materials: engine and cable, and additionally for the generator and cable, and additionally for the current limiting device and distribution device. 5. Aviation integrated electric power plant according to claim 1, characterized in that the cryosystem contains a distribution tank with at least one outlet and one inlet for cryogenic pipelines according to the number of cryogenic circuits. 6. Aviation integrated electric power plant according to claim 1 or 5, characterized in that the distribution tank of the cryosystem includes a circulation cryogenic pump for each cryogenic circuit. 7. Aviation integrated electric power plant according to claim 1, characterized in that the connection of cryogenic circuits can be made through quick couplings to facilitate the repair and maintenance of the power plant. 8. Aircraft integrated electric power plant according to claim. 1 or 2, characterized in that it is made with the ability to use a separate control system for each of the engines, with each of the engines associated with a separate propulsion unit.

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