High conductive arrangement

Abstract

The present invention relates to a power transmission device comprising: an electrical conductor; and a refrigerant transport portion arranged such that, in use, refrigerant is transported in the refrigerant transport portion to maintain the conductor in a high conductivity state.

Description

Technical Field

[0001] The present invention relates to power transmission devices. In particular, it relates to power transmission devices whose efficiency can be improved by cooling using liquid hydrogen or other refrigerants. It is known that superconducting properties can enable efficient power transmission devices because the electrical resistance of certain materials drops to zero below a critical temperature. Background Art

[0002] This superconducting behavior has a number of benefits, such as high component efficiency, low heat losses, and using liquid hydrogen is a known way of maintaining superconducting behavior of a component.

[0003] Today, propulsion systems are shifting toward alternative fuels to reduce the environmental impact of emissions. Electric vehicles and hydrogen-powered vehicles are currently being developed for a wider range of uses.

[0004] In aircraft in particular, while hydrogen-powered flight has been discussed, the industry prefers to use gas turbines for propulsion for a number of technical reasons, including the ability to provide the extra power required for takeoff and climb phases of flight, as well as comparable effectiveness and efficiency during cruise.

[0005] Thus, while there are recognized environmental benefits from the use of alternative fuels, these alternative fuels are not yet in widespread use. The efficiency benefits that can be provided by using superconducting materials have not yet been accepted as being strong enough to promote solutions that deviate from typical fuels and standard combustion. However, in the case of alternative, cryogenic fuels, the possible advantages gained from superconducting arrangements are very attractive.

[0006] Developments are needed to promote the use of alternative fuels and thereby reduce the environmental impact of transport by land, sea or air.

[0007] Busbars and power cables in aircraft or other vehicles are specific examples of power transmission devices. These examples are usually (but not always in the case of busbars) separate components that are electrically isolated by dielectric or insulating layers. In those cases where they are not isolated, these systems are housed in high voltage boxes or compartments with appropriate hazard warnings.

[0008] The inventors of the invention described herein have created a new solution for providing low temperature electrical efficiency that can be used with alternative fuel arrangements for vehicles to make alternative fuels more attractive. Summary of the invention

[0009] Various aspects of the invention are set out in the accompanying claims.

[0010] Viewed from a first aspect, there is provided an electric power transmission device comprising: an electric conductor; and a refrigerant conveying portion arranged such that, in use, refrigerant is conveyed in the refrigerant conveying portion to maintain the conductor in a highly conductive state.

[0011] This arrangement enables the conduction of both electricity and refrigerant. In this way, the conductor remains highly electrically efficient while avoiding the disadvantages of superconductivity.

[0012] In one example, the refrigerant transport portion is formed by an electrical conductor. This arrangement is a particularly space-efficient solution.

[0013] In one example, in use, the refrigerant carried in the refrigerant carrying portion is arranged to provide an electrical insulation function. This provides additional resilience against electrical short circuits in the arrangement. In addition, this advantage is provided by elements that are already used in some current systems, but in a previously undisclosed manner.

[0014] In one example, the transmission device further comprises: a second electrical conductor; and a refrigerant return portion formed between the electrical conductor and the second electrical conductor, the refrigerant return portion being arranged so that: in use, the refrigerant is returned in the portion formed between the electrical conductor and the second electrical conductor. This arrangement allows for an outward path and an inward path for the refrigerant and provides a closed loop system, so that it does not require the provision of additional refrigerant. In addition, the return refrigerant can provide a dielectric protection element to further electrically shield the more current-carrying center conductor.

[0015] In one example, the refrigerant return is arranged between the refrigerant delivery and the outer edge of the power transmission. In this arrangement, the refrigerant return thermally insulates the refrigerant delivery, which is closer to the interior of the transmission and where operation at lower temperatures is critical. Thus, by using the return refrigerant, it reduces the need to keep the outflowing refrigerant cool.

[0016] In one example, the transmission device further comprises a profiled portion arranged to abut the electrical conductor.The use of a profiled portion reduces the total amount of conductors required in the transmission device, thereby reducing the cost of the arrangement.

[0017] In one example, the transport device further comprises a support structure arranged to support the electrical conductors. This arrangement increases the structural strength of the transport device, thereby increasing resilience to damage and increasing reliability. This arrangement also increases the reliability of the positioning of the metallic conductors. These supports help prevent movement of the conductors, which in turn increases the reliability of consistent overall cooling of the refrigerant.

[0018] In one example, the transmission device further comprises an electrical insulation arranged to form an outer layer of the power transmission device. This arrangement reduces the possibility of electrical short circuits or generally affecting nearby electrical equipment. This arrangement also increases the safety of the transmission device.

[0019] In one example, the transmission device further comprises a dielectric arranged to provide electrical insulation within the power transmission device.Such a material is an advantageous choice for electrical insulation within such a power transmission device.

[0020] In one example, the electrical conductor is formed from aluminum. Aluminum has shown advantageous properties for the arrangements described herein.

[0021] In one example, the transmission device also includes a first power transmission device portion; a second power transmission device portion; and a clamp, wherein the first power transmission device portion and the second power transmission device portion are connected by the clamp. This arrangement structure increases the flexibility of the transmission device design. In turn, this increases the ease of manufacturing of the transmission device. By forming the transmission device from a series of clamping parts, the device can be constructed more simply (several shorter parts) and there is less possibility of breakage, defects, etc. in any one part. This also increases the configurations that the transmission device can adopt (compared to one long rigid transmission device), making it easier to insert into any particular space, etc.

[0022] In one example, the transmission device further comprises an isolation interrupter arranged between the first power transmission device portion and the second power transmission device portion. The interrupter provides an interruption in the conductive circuit so that greater control of the conductive path can be obtained.

[0023] In one example, the power transmission device includes a T-shaped or Y-shaped joint. This arrangement structure may be beneficial when introduced into a specific space and used to control the electrical path of the transmission device. Such a joint also allows the transmission device to provide refrigerant and power to more areas (via two branching sub-transmission devices). Therefore, this is easier to manufacture and provide than via two separate transmission devices.

[0024] Viewed from another aspect, there is provided an aircraft electrical system comprising any power transmission device as described above. Use of the transmission device in an aircraft electrical system is particularly advantageous because refrigerant may already be present in an aircraft utilizing fuel cells or the like. Including the transmission device in an aircraft electrical system has significant synergistic advantages.

[0025] Viewed from another aspect there is provided an aircraft comprising any power transmission arrangement as described above. Use of the transmission arrangement in an aircraft is particularly advantageous as refrigerant may already be present in an aircraft utilising fuel cells or the like. Including the transmission arrangement in an aircraft has significant synergistic advantages.

[0026] Viewed from another aspect, a method of carrying an electrical signal along an electric power transmission device is provided: cooling a conductor to a high conductivity region with a refrigerant; supplying an electrical signal to the conductor; continuing to cool the conductor; thermally and electrically insulating the conductor. Using a high conductivity region instead of a currently used superconducting region maintains high performance but reduces the risks associated with superconductivity. This is a safer yet more reliable method to perform than is currently known. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] One or more embodiments of the present invention will now be described, by way of example only, with reference to the following drawings, in which:

[0028] Figure 1A shows a schematic cross-sectional view of a standard power transmission arrangement for a vehicle;

[0029] Figure 1B A schematic cross-sectional view showing a new power transmission arrangement for a vehicle;

[0030] Figure 2A A schematic cross-sectional view showing a new power transmission arrangement for a vehicle;

[0031] Figure 2B Shows Figure 2A A simplified and enlarged version of part D of Figure 2A A new power transmission arrangement for a vehicle is shown;

[0032] Figure 3A A schematic cross-sectional view showing a new power transmission arrangement for a vehicle;

[0033] Figure 3B Shows Figure 3A A simplified and enlarged version of part E of Figure 3A A new power transmission arrangement for a vehicle is shown;

[0034] Figure 4A A schematic cross-sectional view showing a new power transmission arrangement for a vehicle;

[0035] Figure 4B Shows Figure 4A A simplified and enlarged version of Section F, Figure 4A A new power transmission arrangement for a vehicle is shown;

[0036] Figure 5 A schematic diagram showing a spigot and socket joint between two parts of a transmission device.

[0037] Figure 6 A schematic diagram showing a joint between two parts of a transmission device.

[0038] Fig. 7A A schematic diagram showing a new power transmission arrangement for a vehicle with a coupling;

[0039] Figure 7B A schematic diagram showing a new power transmission arrangement for a vehicle with a coupling;

[0040] Fig. 8A A schematic cross-sectional view showing a new power transmission arrangement for a vehicle;

[0041] Figure 8B Shows Fig. 8A A simplified and enlarged version of part J, Fig. 8A A new power transmission arrangement for a vehicle is shown;

[0042] Fig. 9A A schematic cross-sectional view showing a new power transmission arrangement for a vehicle;

[0043] Fig. 9B a schematic cross-sectional view showing a new power transmission arrangement for a vehicle; and

[0044] Fig. 9C A schematic cross-sectional view of a new power transmission arrangement for a vehicle is shown.

[0045] Any reference to prior art documents in this specification should not be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the art. As used in this specification, the words "include", "comprise" and similar words should not be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean "including but not limited to". The present invention is further described with reference to the following examples. It should be understood that the claimed invention is not intended to be limited by these examples in any way. It will also be appreciated that the present invention covers not only the various embodiments but also the combination of the embodiments described herein.

[0046] The various embodiments described herein are presented only to help understand and teach the claimed features. These embodiments are provided only as representative samples of embodiments and are not exhaustive and / or exclusive. It should be understood that the advantages, embodiments, examples, functions, features, structures and / or other aspects described herein should not be considered as limitations on the scope of the invention defined by the claims or limitations on the equivalents of the claims, and other embodiments may be utilized and may be modified without departing from the spirit and scope of the claimed invention. In addition to those specifically described herein, various embodiments of the present invention may appropriately include, consist of or substantially consist of the disclosed elements, components, features, parts, steps, devices, etc. Appropriate combination. In addition, the present disclosure may include other inventions that are not currently claimed but may be claimed in the future. DETAILED DESCRIPTION

[0047] The invention described herein relates to power transmission devices. In particular, the invention relates to electrically efficient, cooled power transmission lines. Such power transmission lines may be cables for conducting electricity. The cables described herein may also transport refrigerants.

[0048] Electrical conductors may be cooled using cryogenic fluids such as liquid helium (below about 4 Kelvin), liquid hydrogen (between about 14 Kelvin and about 20 Kelvin), liquid neon (between about 24 Kelvin and about 27 Kelvin), liquid nitrogen (between about 63 Kelvin and about 77 Kelvin), and liquid oxygen (between about 55 Kelvin and about 90 Kelvin). Many superconducting materials are known, which are materials having an electrical resistance that drops to zero (specifically, to zero resistance under direct current [DC] conditions, and some slight resistance under alternating current (AC) conditions) once the material is cooled beyond a certain "supercold" temperature, under some critical values ​​that take into account external magnetic fields and electric current transport.

[0049] Such materials provide high electrical efficiency transmission systems. However, there are difficulties in using superconductivity in vehicle arrangements. In particular, superconductivity relies on materials being permanently maintained in a superconducting phase. If a material leaves the superconducting phase, the resistance of the material increases from zero. In this case, a current passing through a material with a non-zero resistance causes heating of the material. This in turn causes an increase in the resistance of the material, which in turn causes more heating. When this happens, a positive feedback loop causes a rapid increase in the temperature of the material. This heat is transferred to a nearby coolant (liquid hydrogen, etc.), which then boils in large quantities. This is referred to in some fields as "quenching". "Quenching" may also occur if the current passing through a superconducting material exceeds the critical current value of the material.

[0050] Such "quench" events can be very dangerous, can severely damage electrically connected components, and can waste large amounts of refrigerant. In particular, if these events occur on an aircraft or other similar vehicle, the safety of the passengers may be at risk.

[0051] The invention described herein relates to a conductive cable for efficient power transmission. The cable also improves safety by significantly reducing the risks associated with typical wiring solutions and superconductors. In addition, the cable disclosed in the present invention also takes up less space than existing solutions.

[0052] Reference now Figure 1A , shows a typical power transmission arrangement 10 comprising a series of cables 11, 12, 13, 14, 15, 16. The typical cables may be made of copper, each having a diameter A of about 16 mm for a transmission arrangement having a diameter B of about 55 mm.

[0053] In a common electrical bus in an aircraft, the conductors are in ambient air conditions or sometimes have blown air for cooling purposes. Heat transfer from such current carrying conductors can occur by conduction (usually dominated by axial conduction into a cold compartment), convection cooling at flight altitude (usually about 20,000 to 40,000 feet) or radiant heat emission confined to a non-pressurized compartment. Heat will be lost axially when the conductor is hotter than the compartment the conductor is entering. Axial conduction of heat into a cold compartment occurs along the conductor from a warmer structural boundary to a cooler structural boundary.

[0054] For this reason, the heat transfer of such conventional bus and power cabling systems is limited. Typically, the power bus system is routed in the fuselage of the aircraft and in unpressurized areas of the aircraft. For aircraft using electric propulsion (i.e., using the above-mentioned alternative fuels), this routing of the power bus is primarily located in unpressurized areas of the aircraft.

[0055] Due to these limitations, and to achieve high power transmission of, for example, 1 megawatt (MW) of electricity, a design may require 6 OFF 4 / 0 gauge copper cables with a total conductor cross-sectional area of ​​643 square millimeters (mm 2 ).This is Figure 1A The 4 / 0 here refers to the American Wire Gauge rating, where a 4 / 0 is 0.46 inches or 11.684 millimeters (mm) in diameter.

[0056] One way to reduce the effects of Joule heating is to use higher voltages. The highest DC voltage seen in aircraft today is 270 volts DC (V DC). Voltages in the range of 700V DC, 1kV DC, and up to about 3kV DC are being considered for some potential electric propulsion aircraft. These very high voltages are challenging because partial discharge effects can occur at voltages above 327V at any pressure or distance (327V is the minimum breakdown voltage at any pressure or distance in air). This makes it more challenging to integrate such high voltage systems into the power transmission arrangement.

[0057] Some modern propulsion systems utilize refrigerants, such as in fuel cell systems. In such systems, there is a refrigerant that can be directed to cool the cable. In this way, the resistivity of the copper is reduced, and therefore benefits can be gained in terms of increasing the current carrying capacity of the cable, or reducing the size of the cable while keeping the current carrying capacity the same.

[0058] The modern operating temperature of the power bus system is usually defined by the ambient and operating conditions of the aircraft and is between -55 and +260 degrees Celsius (°C). In this range, the electrical conductivity of aluminum is lower than that of copper, i.e. its resistance per unit area is higher. However, in an arrangement using a refrigerant, the temperature of the power bus system can be cooled to a lower temperature below this range.

[0059] The inventors of the present invention have recognized the risks associated with superconducting regions, in addition to the obvious benefits of using them, and have proposed a novel system for improved power transmission. Aluminum has a lower density than copper, and at low temperatures (approximately below 100 Kelvin), its resistivity is similar to or lower than that of copper.

[0060] Below 100 Kelvin, we refer to aluminum as being in a "highly conductive" state until the temperature reaches 1.175 Kelvin, at which point it becomes a superconductor. We define highly conductive materials as typical conductive materials that experience a sharp or nonlinear drop in specific resistivity at low temperatures (less than 100 Kelvin) without reaching a superconducting state. The present invention exploits this highly conductive state in order to provide a robust yet electrically efficient and effective power transmission system.

[0061] Aluminum has a lower density than copper, which means that when the room temperature ( Figure 1A ) of standard copper wiring layout structure and high conductivity area ( Figure 1B ) in comparison to the size of the aluminum wiring arrangement structure in FIG. 1 , the size of the wiring arrangement structure is significantly reduced.

[0062] In particular, when aluminum is cooled to 20 Kelvin, its conductivity increases by about 3500 times compared to room temperature. The conductivity of aluminum at 77 Kelvin is about 324 times that of aluminum at room temperature. When the resistivity of aluminum at 20 Kelvin is compared to the resistivity of copper at room temperature, it increases by a factor of 2246. This is equivalent to a 5000-fold and 2246-fold reduction in conductor mass from aluminum or copper at room temperature, respectively. See Table 1 for experimental details on the resistivity of aluminum and copper at different low temperatures.

[0063]

[0064] Thus, significant benefits may result from using coolant, which may already be present in the propulsion system, to transform the cable material into a highly conductive state.

[0065] Table 1 shows that below 77 Kelvin, when lightweight aluminum enters the high conductivity region, the resistivity of aluminum drops below that of copper. Therefore, the system can advantageously use liquid hydrogen to cool aluminum components because liquid hydrogen has a temperature of less than 30 Kelvin. Therefore, using liquid hydrogen as a coolant enables aluminum to be cooled sufficiently to be more conductive than copper.

[0066] As can be readily appreciated, as the resistivity of aluminum drops below that of copper, and given the lower density of aluminum compared to copper, significant benefits can result in the overall size and mass of the cable required.

[0067] Reference now Figure 1B , shows a high-conductivity power transmission device 100 comprising a 1 MW aluminum cable 110 at 270 V DC (below the Paschen minimum). The high-conductivity equivalent 110 has a diameter of about 2.4 mm, compared to a total transmission device 10 diameter of 55 mm resulting from six 16 mm diameter copper cables 11, 12, 13, 14, 15, 16; see Figure 1B The measured value C in Figure 1A The transmission device 10 to Figure 1B The size of the power transmission device is significantly reduced. In addition, considering the relative density, the conductor mass per unit length of the power transmission device 100 is about 16.5 g / m, compared with the conductor mass per unit length of the transmission device 10 of about 7.2 kg / m. Therefore, when using Figure 1B There is also significant weight savings when using the highly conductive arrangement shown in FIG.

[0068] Thus, the system 100 proposed herein is approximately 400 times lighter than contemporary systems and is significantly more efficient electrically, using less than half the voltage ( Figure 1A Use 700V AC, and Figure 1B270V DC was used). Calculations showing this significant weight reduction are shown in Tables 2 and 3.

[0069] Therefore, there are significant benefits when using a high conductivity power transmission device. This may also be referred to as a high conductivity electrical bus, a high conductivity bus, a high conductivity cable.

[0070] One option for cooling the cable to the high conduction region is to immerse the cable in liquid hydrogen, however, this may not be the most efficient or effective method. Therefore, examples of efficient and effective cable constructions are now discussed.

[0071] The present high conductivity cables provide a number of efficiency benefits compared to existing systems. In particular, when compared to a more electric aircraft (MEA) network or even a high voltage (HV) network, the use of high conductivity cables in the network results in increased efficiency and reduced mass. As shown in Table 2, an aluminum high conductivity network at 20 Kelvin is compared to a MEA and HV network at room temperature while delivering 1 MW of power.

[0072] Table 2 - Shows the characteristics of the currently disclosed high-conductivity cables in the network and the MEA network and HV network

[0073]

[0074] Clearly, electrical efficiency benefits are provided by using the high conductivity cables of the present disclosure in a network. The system of Table 2 is a 1 MW electrical network using 10 m aluminum bus bars.

[0075] Additionally, there are structural benefits particularly related to weight.Table 3 uses the same parameters as Table 2, and only allows the system to increase in temperature by 5°C in 1 minute.

[0076] Table 3 - Shows the characteristics of the currently disclosed high-conductivity cables used in the network and the MEA network and the HV network

[0077]

[0078] Table 3 clearly shows the weight and volume advantages of the high conductivity cables used in the network disclosed herein.

[0079] As mentioned above, highly conductive aluminum can be used as conductor for busbars and feeder cables. Aluminum can be supplied by LH from liquid refrigerant storage. 2 Cooling, by complete immersion in LH 2 The highly conductive conductor is then wrapped in a dielectric and insulation to perform well when handling high voltages.

[0080] Reference now Figure 2A and Figure 2B, showing a schematic diagram of a new power transmission arrangement 200 for a vehicle. Figure 2A A schematic cross-sectional view of a power transmission arrangement 200 is shown. Figure 2B Shows Figure 2A An enlarged schematic diagram of part D of FIG.

[0081] Figure 2A A transmission device 200 is shown. The transmission device 200 has a central core of a cryogen, such as liquid hydrogen 210. The transmission device 200 has an aluminum layer 220 surrounding the hydrogen 210. The transmission device 200 has a dielectric layer 230 surrounding the aluminum layer 220. The transmission device 200 has an outer surface of an insulating portion 240. The insulating portion 240 surrounds the dielectric 230.

[0082] Figure 2A The cable arrangement 200 allows both the transmission of electrical signals and refrigerant 210, so the cable provides dual purpose in a system that uses refrigerant and needs to transmit the refrigerant. In addition, the refrigerant delivery also provides the cooling function of the aluminum cable 220.

[0083] For the sake of clarity, Figure 2B Shows Figure 2A The layers are clearly shown, with the center being the refrigerant 210 ( Figure 2B The bottom of the ), followed by aluminum 220, dielectric 230, and the outermost layer is an insulating portion 240 ( Figure 2B of the display).

[0084] The dielectric layer 230 and the insulating layer 240 provide electrical isolation of the electrical energy carried in the electrical conductor 220. The refrigerant 210 may also function as an electrical insulator.

[0085] In use, the aluminum 220 contains the refrigerant 210, which can be pressurized liquid hydrogen or cryogenic gaseous hydrogen, while also carrying electrical current to the required load. The aluminum tube 220 will then be surrounded by a dielectric layer 230 and an insulating layer 240. To simplify the manufacturing process, this can be spray foam, cryogenic blankets and / or vacuum, as this allows for easy detection of leaks and is a suitable insulator. This structure and its manufacturing techniques reduce manufacturing complexity compared to power transmission devices immersed in liquid hydrogen that require mechanical support.

[0086] At low temperatures, the aluminum tube 220 is partially supported by the refrigerant 210 due to an increase in tensile strength of up to 40%. The aluminum tube 220 can also be doped with graphene to enhance its strength, which has a minimal effect on the conductivity of the tube 220. The aluminum 220 can also be supported by simple, inert and lightweight moldings such as glass fiber reinforced plastic, which will help improve its robustness. Therefore, these manufacturing steps can be taken to improve the robustness of the design of the cable 200.

[0087] Reference now Figure 3A and Figure 3B , showing a schematic diagram of a new power transmission arrangement 300 for a vehicle. Figure 3A A schematic cross-sectional view of a power transmission arrangement 300 is shown. Figure 3B Shows Figure 3A An enlarged schematic diagram of part E of FIG.

[0088] Figure 3A A transmission device 300 is shown. The transmission device 300 has a central core of a refrigerant, such as liquid hydrogen 310. The transmission device 300 has an aluminum layer 320 surrounding hydrogen 310. The transmission device 300 has an insulating layer 330 surrounding the aluminum layer 320. The transmission device 300 has a gaseous refrigerant layer 312 surrounding the insulating layer 330. The transmission device 300 has a second aluminum layer 322 surrounding the gaseous refrigerant layer 312. The transmission device 300 has a dielectric layer 340 surrounding the second aluminum layer 322. The transmission device 300 has an outer surface of an insulating portion 332. The insulating portion 332 surrounds the dielectric 340.

[0089] In use, the cable 300 can transmit current along the inner aluminum tube 320, which holds and is cooled by the central refrigerant 310, which can be liquid hydrogen. The outer aluminum tube 322 holds and transports (together with the inner aluminum tube 320 and the insulation 330) a second refrigerant 312. The second refrigerant 312 can be gaseous hydrogen. The second refrigerant 312 can be a returned refrigerant that has been used in some way. This can be via use in a fuel cell or heat exchanger function. The returned refrigerant 312 can be at a temperature sufficient to place the aluminum in a high conduction area. Alternatively, the returned refrigerant 312 may not be at a temperature sufficient to place the aluminum in a high conduction area. Therefore, the returned refrigerant 312 can be in a gas phase. The returned refrigerant 312 can be in a high pressure gas phase. The returned refrigerant 312 provides further protection to prevent external heat from reaching and impacting the refrigerant 310 and thus impacting the high conduction inner aluminum tube 320.

[0090] Using the same conduit to carry the gaseous hydrogen 312 back from where the refrigerant 312 may have performed a function (e.g., heat exchange at the motor of a vehicle's propulsion system) provides two advantages. The first advantage relates to saving the weight of having two separate cables, one carrying liquid refrigerant outward and one carrying gaseous refrigerant inward. This will result in less overall material, especially in terms of insulation, support, and dielectric materials. The second advantage relates to cooling the conductors of opposite polarity (in the case of the conductors ... Figure 3A322). The opposite polarity conductor can be used as a shield to protect the cable 300 from stray electric and magnetic fields, and vice versa. The opposite polarity conductor can also be used as a ground for components to which the cable is connected.

[0091] For the sake of clarity, Figure 3B Shows Figure 3A The layers are clearly shown, with the center of the cable 300 being the refrigerant 310 ( Figure 3B ), followed by aluminum 320, insulating portion 330, second refrigerant or gas-phase refrigerant 312, second aluminum layer 322, dielectric 340 and insulating portion 332 ( Figure 3B of the display).

[0092] The polymer dielectrics used in typical superconducting and high-voltage cables usually have a dielectric strength of about 10-15,000 V / mm. Gaseous hydrogen in normal conditions has a lower minimum voltage breakdown than air. However, using liquid hydrogen and increasing the pressure to 3 bar (which is near the pressure required to use cryogenic hydrogen in fuel cells) increases the dielectric strength to 9,000 V per mm. This is comparable to polymer dielectrics. In this way, cables can be designed to use high-pressure liquid hydrogen instead of polymer dielectrics, which results in a reduction in the quality of the cable.

[0093] Reference now Figure 4A and Figure 4B , showing a schematic diagram of a new power transmission arrangement 300 for a vehicle. Figure 4A A schematic cross-sectional view of a power transmission arrangement 400 is shown. Figure 4B Shows Figure 4A An enlarged schematic diagram of part F.

[0094] Figure 4A A transmission device 400 is shown. The transmission device 400 has a central core of a refrigerant, such as liquid hydrogen 410. The transmission device 400 has an aluminum layer 420 surrounding hydrogen 410. The transmission device 400 has a dielectric layer 430 surrounding the aluminum layer 420. The transmission device 400 has an insulating layer 440 surrounding the dielectric 430. The transmission device 400 has a gaseous refrigerant layer 412, which may be gaseous hydrogen, surrounding the insulating layer 440. The transmission device 400 has a second aluminum layer 422 surrounding the gaseous refrigerant layer 412. The transmission device 400 has a second dielectric layer 432 surrounding the second aluminum layer 422. The transmission device 400 has an outer surface of an insulating portion 442. The insulating portion 442 surrounds the second dielectric layer 432.

[0095] As described above, refrigerant 412, which may be return refrigerant 412, may be carried in second aluminum tube 422. In this manner, cable 400 provides thermal and electrical shielding to both aluminum tubes 420, 422 through refrigerant 412, dielectrics 430, 432, and insulation 440, 442. In this manner, a very robust cable is provided that is capable of carrying refrigerant while achieving efficient current carrying capabilities through high conduction regions and high resilience to short circuits due to high breakdown voltage.

[0096] For the sake of clarity, Figure 4B Shows Figure 4A The layers are clearly shown, with the center of the cable 400 being the refrigerant 410 ( Figure 4B ), followed by aluminum 420, dielectric 430, insulating portion 440, second refrigerant or gas-phase refrigerant 412, second aluminum layer 422, second dielectric layer 432, and second insulating layer 442 ( Figure 4B of the top).

[0097] It may be undesirable, for construction convenience or other reasons, to construct a transmission device of great length as shown in Figures 2 to 4. One solution is to form the various sections of the transmission device separately and then join them together.

[0098] like Figure 5 , a schematic diagram of a socket joint between two parts 502, 504 of a transmission device 500 is shown. Figure 5 In the example shown, portion 502 of transmission device 500 has a first end 502' and a second end 502". Portion 504 has a first end 504' and a second end 504". First end 502' of portion 502 is arranged to be connected to second end 504" of second portion 504. First end 502' of portion 502 is smaller than second end 504" of second portion 504, thereby providing a good fit when connected.

[0099] exist Figure 5 In the arrangement of the system, a clamp or similar fixture can be used to provide a connection between the two parts 502, 504 of the cable 500. This is easier to construct than a system that requires terminals and connectors within the parts of the cable. Alternatively or additionally, the parts 502, 504 can be connected via an interference fit such as a threaded connection. Since one part (in the example shown, part 502) can be connected to another part (in the example shown, part 504), the cable or transmission device 500 can be composed of a series of smaller cables or transmission devices to provide a suitable length of transmission device 500.

[0100] The use of a clamp or similar fixture may be advantageous as the clamp may provide connections for other components such as fault protection and power electronics. Such components may be connected to the interrupted section of cable to provide the best reading. Furthermore, such an interrupted section may be made of a ring of insulating material which will interrupt the flow of electrical current but not the liquid hydrogen supply. Figure 6 A schematic diagram is shown in FIG.

[0101] like Figure 6 , a schematic diagram of a joint between two parts 602, 604 of a transmission device 600 is shown. The transmission device 600 includes two highly conductive conduit parts 602, 604. The two parts 602, 604 are separated by an interrupter 605. The interrupter 605 is an insulating material to provide an interruption in the conductive circuit. This ensures that the current passing through the two parts 602, 604 is passed to the electrical component 606. The electrical component 606 is connected to the parts 602, 604 by electrical conductors 606' and 606", respectively. The electrical conductors 606' and 606", respectively, are connectors to electrical clamps (or O-rings) 607' and 607", respectively. The interrupter 605 can be formed of rubber to provide flexibility in the transmission device 600.

[0102] Other arrangements for combining electrical buses can be envisioned. In particular, if the transport device needs to be split in two, for example, to deliver liquid hydrogen to two different locations, a joint can be used in the transport device. Fig. 7A and Figure 7B As shown, this can be a T-joint or a joint with a non-90 degree angle (Y-joint).

[0103] Specifically, Fig. 7A A transport device 700 is shown having sections 710, 712, and 714. The first section 710 shows the main entry section of the transport device 700. Liquid hydrogen travels into the first section 710 as shown by arrow G. Some of the liquid hydrogen that enters the first section 710 continues into the second section 712 and exits the second section 712 in the direction of arrow H. Some of the liquid hydrogen that enters the first section 710 continues into the third section 714 and exits the third section 714 in the direction of arrow I. Figure 7B A similar arrangement is shown, with similar reference numerals used to refer to similar components of the transmission device 700. It can be seen that the third portion 714 is at a non-90 degree angle to the first portion 710.

[0104] In an example of an arrangement structure described herein, the cable may include a profiled portion for supporting the aluminum (or other metal) that forms the main conductive portion of the cable. The use of a profiled portion allows the total amount of aluminum used in the cable to be reduced. In one example, the profiled portion is made of a strong, lightweight, non-reactive material (such as glass reinforced plastic), which may then reduce the weight of the cable. Fig. 8A and Figure 8B A schematic diagram of a possible shaped part design is shown in FIG.

[0105] Fig. 8A A transmission device 800 is shown. The transmission device 800 has a central core of a refrigerant, such as liquid hydrogen 810. The transmission device 400 has a profile layer 820 surrounding the hydrogen 810. The transmission device 800 has an aluminum layer 830 surrounding the profile layer 820. The transmission device 800 has a dielectric layer 840 surrounding the aluminum 430. The transmission device 800 has an insulating layer 850 surrounding the dielectric layer 840.

[0106] For the sake of clarity, Figure 8B Shows Fig. 8A The layers are clearly shown, with the center of the cable 800 being the refrigerant 810 ( Figure 8B ), followed by the molding 820, aluminum 830, dielectric 840, and the outermost insulating portion 850 ( Figure 8B of the display).

[0107] Fig. 8A and Figure 8B The example shown shows a cable with a much smaller cross-section of the aluminum conductor 830. In this example, the aluminum 830 is not in contact with the liquid hydrogen 810, and therefore, the design may result in the aluminum 830 not being cooled as in the above-described arrangement where the aluminum 830 and the refrigerant 810 are adjacent.

[0108] Fig. 8A and Figure 8B The arrangement shown in is advantageous because the use of the profile 820 and aluminum 830 results in a flexible cable 800. The aluminum 830 can be in the form of a highly conductive tape wrapped around the inner profile 820. The profile 820 then supports the aluminum 830, which can help prevent the conductor from falling to the bottom of the cryogenic fluid, which would result in uneven cooling on the conductor. This can occur in a layered cable where the aluminum is surrounded by a layer of refrigerant, etc. The mechanical support helps keep the aluminum in a central position within the refrigerant to allow for uniform cooling. The aluminum or other suitable conductive component can be in the form of a tape or tube or other similar construction.

[0109] The arrangements shown herein may be mixed, such that components and arrangements from one drawing may be used in other drawings. Fig. 8A and Figure 8BThe cable 800 may have a second low temperature portion 412 (which may be in a gaseous state, etc.), such as Figure 4A and Figure 4B The advantages of these layers have been explained herein, so these layers and their associated advantages are portable across all examples described herein.

[0110] The support of the aluminum layer can be used to improve the structural stability of the cable when immersed in a cryogenic fluid. Therefore, additional support structures can be introduced into the examples described herein. The tradeoffs to be considered are the additional complexity of the construction of the cable, the complexity associated with arranging any connectors and terminals for the different parts of the cable, and the subsequent effects of the refrigerant flowing through the cable.

[0111] Reference now Fig. 9A , shows an example of a transmission device 900. The transmission device 900 has a central core conductor 910. In one example, the core conductor 910 is made of aluminum for the above advantages. There is a dielectric layer 920 around the central conductor 910. Fig. 9A In the example shown, there is a support structure 940. The support structure 940 with inwardly protruding supports is connected to the dielectric layer 920. There is a refrigerant 930 between the support structure 940 to keep the central core in a high conduction condition. For the above advantages, the refrigerant 930 can be liquid hydrogen. An insulating layer 950 surrounds the support structure.

[0112] As discussed above, the various layers of these transmission devices may be varied to ensure that the cables conduct electricity and carry refrigerant effectively, efficiently, and safely. Fig. 9B and Fig. 9C The other transmission devices shown in show such examples.

[0113] refer to Fig. 9B In the illustrated example, a cable 900' is shown. The cable 900' comprises a center conductor 910', a refrigerant 930', a support structure having a support member 940', and an insulating outer layer 950'. In this example, the refrigerant 930' can be high pressure liquid hydrogen used as a high efficiency dielectric, as described above. In this way, space in the cable 900' can be saved by not using a dedicated dielectric layer.

[0114] exist Fig. 9C In the example shown, cable 900'' is shown. Although cable 900'' is larger than Fig. 9A and Fig. 9B , but for clarity of the illustration, it has been exaggerated and does not indicate the necessarily larger cables.

[0115] The cable 900" comprises (extending radially outward from the center of the cable 900") a center conductor 910", a refrigerant 930", a support structure 940" having supports, an insulating layer 950", a second support layer 942", a high pressure refrigerant layer 912" which may be in gaseous form, a second conductor layer 912", and an insulating outer layer 952". In this example, a combination of both a current carrying conductor and a supported inner highly conductive conductor is shown. The high pressure refrigerant 912" may be gaseous hydrogen.

[0116] Thicker or additional layers of profiles may be used to mechanically support the aluminum and therefore reduce the total amount of aluminum required in the cable. Dielectrics may be used instead of high pressure liquid hydrogen. The advantage of using dielectrics is that no high pressure refrigerant is required, so the dangers and difficulties of handling such refrigerants may be slightly offset. Using dielectrics provides greater robustness in light of any failure in the cooling as the dielectric will continue to work.

[0117] Thus, an effective and efficient power transmission device is described herein. The system provides a number of advantages as described above. Additional advantages include the ability to more easily transport refrigerants through the use of the system, and to more easily integrate clean fuels into the generation of propulsion, whether through the combustion of the refrigerant or the generation of electricity through a fuel cell. Thus, the system helps to reduce harmful emissions in modern propulsion systems.

[0118] Using pure and cryogenic oxygen and hydrogen, modern propulsion systems can be replaced with smaller volumes (higher power density) and lighter masses (higher specific power) for propulsion generation. Using liquid hydrogen and liquid oxygen (i.e., as a cryogen) also offers advantages in power density and cooling factors.

[0119] Although the power transmission device described herein is primarily discussed from the perspective of aircraft for use with propulsion systems, other vehicles such as spacecraft, submarines, etc. may also carry oxygen, liquid oxygen, or gaseous or liquid hydrogen for propulsion systems. The cable arrangement disclosed herein will bring benefits to each of these applications.

[0120] Using refrigerants to generate propulsion offers many advantages over using fossil fuels. Producing water instead of harmful gaseous emissions (NOx, CO 2 In addition, the operating noise level of the vehicle can also be significantly reduced. In a specific example, due to the lack of high-speed exhaust gases, the take-off and landing phases of an aircraft can be carried out with significantly reduced noise levels.

[0121] Therefore, the application scope of the cable arrangement structure may include automotive, aerospace, home or commercial fields.

[0122] Another benefit of using a fuel cell as disclosed herein over a combustion engine is the avoidance of the formation of microbial colonies that occur in existing aircraft kerosene fuel tanks. Currently, cleaning such tanks requires the use of environmentally damaging detergents and insecticides. In some cases, such cleaning may need to be performed after each long-distance flight. Therefore, reducing cleaning has further environmental benefits.

Claims

1. A power transmission device, comprising: Electrical conductors; as well as A refrigerant carrying portion is arranged such that, in use, refrigerant is carried in the refrigerant carrying portion to maintain the conductor in a highly conductive state.

2. The power transmission device according to claim 1, wherein: The refrigerant transport portion is formed by the electrical conductor.

3. The power transmission device according to claim 1 or 2, wherein: In use, the refrigerant conveyed in the refrigerant conveying portion is arranged to provide an electrical insulation function.

4. The power transmission device according to any one of claims 1 to 3, further comprising: a second electrical conductor; as well as A refrigerant return portion is formed between the electrical conductor and the second electrical conductor, the refrigerant return portion being arranged such that, in use, refrigerant returns in a portion formed between the electrical conductor and the second electrical conductor.

5. The power transmission device according to claim 4, wherein: The refrigerant return portion is disposed between the refrigerant carrying portion and an outer edge of the power transmission device. 6 . The power transmission device according to claim 1 , further comprising a shaped portion arranged to abut against the electrical conductor. 7 .

7. A power transmission device according to any one of claims 1 to 6, further comprising a support structure arranged to support the electrical conductor.

8. The power transmission device according to any one of claims 1 to 7, further comprising an electrical insulation portion arranged to form an outer layer of the power transmission device.

9. A power transmission device according to any one of claims 1 to 8, further comprising a dielectric arranged to provide electrical insulation within the power transmission device.

10. The power transmission device according to any one of claims 1 to 9, wherein: The electrical conductor is formed from aluminum.

11. The power transmission device according to any one of claims 1 to 10, wherein: The power transmission device comprises: a first power transmission device portion; a second power transmission device portion; and Fixtures, Wherein, the first power transmission device part and the second power transmission device part are connected by the clamp.

12. The power transmission device according to claim 11, wherein: The power transmission device further includes an insulation interrupter disposed between the first power transmission device portion and the second power transmission device portion.

13. The power transmission device according to any one of claims 1 to 12, wherein: The power transmission device includes a T-shaped or Y-shaped joint.

14. An aircraft electrical system comprising a power transmission device according to any one of claims 1 to 13.

15. An aircraft comprising the power transmission device according to any one of claims 1 to 13.

16. A method for transmitting an electrical signal along a power transmission device: Cooling the conductor with a refrigerant to a high-conductivity region; Provide electrical signals to conductors; Continue cooling the conductor; The conductor is thermally and electrically insulated.

Images