Superconducting generator and superconducting rotary electric machine system

Abstract

A superconducting generator according to the present disclosure is provided with: a rotor (4) that includes a high-temperature superconducting coil (15) that is cooled by liquid hydrogen; an armature (3); and a hydrogen gas container (6) that, in order to cool the armature (3), accommodates the armature (3), the high-temperature superconducting coil (15), and hydrogen gas that has been converted from liquid hydrogen after cooling the high-temperature superconducting coil (15).

Description

Superconducting generator and superconducting rotating electric machine system

[0001] The present disclosure relates to a superconducting generator and a superconducting rotating electric machine system.

[0002] In recent years, superconducting generators have been developed that have rotors that use superconducting wires as rotating field windings. Superconducting generators have higher power generation efficiency than commercially available generators that use copper wires, and therefore consume less power.

[0003] A known superconducting generator is a low-temperature superconducting generator in which a field winding is wound with a low-temperature superconducting wire (see, for example, Patent Document 1).

[0004] Japanese Unexamined Patent Publication No. 185063 / 1983

[0005] A low-temperature superconducting generator such as that described in Patent Document 1 is cooled with liquid helium to achieve a superconducting state. The evaporated helium gas is recondensed in a refrigerator. Because helium is expensive, it is not discarded into the atmosphere but is reused by being recondensed in the refrigerator. However, there is a problem in that power is consumed when recondensing the helium gas in the refrigerator.

[0006] Therefore, an object of the present disclosure is to provide a superconducting generator and a superconducting rotating electric machine system that can reduce power consumption.

[0007] The superconducting generator of the present disclosure includes a rotor including a high-temperature superconducting coil cooled by liquid hydrogen, an armature, the armature and the high-temperature superconducting coil, and a hydrogen gas container that contains hydrogen gas converted from liquid hydrogen by cooling the high-temperature superconducting coil, for cooling the armature.

[0008] According to the present disclosure, power consumption can be reduced by cooling the high-temperature superconducting coil to convert liquid hydrogen into hydrogen gas, which is stored in a hydrogen gas container and used to cool the armature.

[0009] FIG. 1 is a diagram showing the configuration of a superconducting rotating electric machine system according to a first embodiment. FIG. 2 is a diagram showing the detailed configuration of a superconducting generator SCG (Superconducting Generator). FIG. 3 is a diagram showing a tube TB. FIG. 4 is a diagram showing the configuration of a superconducting rotating electric machine system according to a second embodiment. FIG. 5 is a diagram showing the configuration of a superconducting rotating electric machine system according to a third embodiment. FIG. 6 is a diagram showing the configuration of a superconducting rotating electric machine system according to a fourth embodiment. FIG. 7 is a diagram showing the configuration of a superconducting rotating electric machine system according to a fifth embodiment.

[0010] Hereinafter, embodiments will be described with reference to the drawings. Embodiment 1. In addition to low-temperature superconducting generators, there are also high-temperature superconducting generators wound with high-temperature superconducting wire. High-temperature superconducting generators can enter a superconducting state even with liquid hydrogen, which has a higher temperature than liquid helium. If a high-temperature superconducting generator is cooled with liquid hydrogen, the evaporated hydrogen gas can be used as fuel for a hydrogen gas turbine. In such a configuration, there is no need to re-condense hydrogen, and power consumption can be reduced accordingly. As a result, high-temperature superconducting generators can achieve improved generator efficiency and reduced maintenance costs by eliminating the need for a refrigerator, compared to low-temperature superconducting generators. Therefore, in this embodiment, a high-temperature superconducting generator is used as the superconducting generator.

[0011] 1 is a diagram showing the configuration of a superconducting rotating electric machine system according to embodiment 1. The superconducting rotating electric machine system includes a liquid hydrogen tank 2, a liquid hydrogen supply valve 7, a superconducting generator SCG, a branch valve 8, and a hydrogen gas turbine 5. The superconducting generator SCG is a high-temperature superconducting generator.

[0012] The superconducting generator SCG includes an armature 3, a rotor 4, and a hydrogen gas container 6. A liquid hydrogen supply valve 7 is connected to the liquid hydrogen tank 2 by a pipe P1 and to a branch valve 8 by a pipe P2.

[0013] Liquid hydrogen from the liquid hydrogen tank 2 is supplied to the rotor 4 of the superconducting generator SCG via a pipe P1, a liquid hydrogen supply valve 7, a pipe P2, a branch valve 8, and a pipe TB.

[0014] The hydrogen gas container 6 accommodates the armature 3, most of the rotor 4, and hydrogen gas. Both ends of the rotor 4 in the direction of the rotation axis protrude from the hydrogen gas container 6.

[0015] The hydrogen gas container 6 has an inlet 9 and an outlet 10. The inlet 9 is connected to the branch valve 8 by a pipe P3. The outlet 10 is connected to the hydrogen gas turbine 5 by a pipe P4.

[0016] 2 is a diagram showing the detailed configuration of the superconducting generator SCG. The superconducting generator SCG includes a hydrogen gas container 6, an armature 3, a magnetic shield 12, and a rotor 4.

[0017] The hydrogen gas container 6 includes an inlet 9 and an outlet 10. The rotor 4 includes a high temperature superconducting coil 15, a hollow support 17, a cryo-damper 16, and a cryostat vessel 14.

[0018] The high-temperature superconducting coil 15 is made of a wound superconducting member and a high-temperature superconducting wire.

[0019] The support material 17 supports the high-temperature superconducting coil 15. The high-temperature superconducting coil 15 is supported by being screwed or embedded in the support material 17. Liquid hydrogen is stored in the hollow space inside the support material 17. The high-temperature superconducting coil 15 is cooled by the liquid hydrogen. The cooling of the high-temperature superconducting coil 15 causes the liquid hydrogen to vaporize and become hydrogen gas. When the amount of liquid hydrogen inside the support material 17 falls below a predetermined value, liquid hydrogen is injected. The hydrogen gas is sent to the hydrogen gas container 6 through pipe TB, branch valve 8, pipe P3, and gas inlet 9.

[0020] The cryostat 14 houses a high-temperature superconducting coil 15 and a hollow support member 17. The inside of the cryostat 14 is kept at a vacuum to prevent heat from entering, so the high-temperature superconducting coil 15 and liquid hydrogen are kept at low temperatures. The cryostat 14 itself is exposed to room temperature, not low temperatures. The cryostat 14 is made of a material such as SUS (stainless steel) or GFRP (glass fiber reinforced plastics).

[0021] The branch valve 8 is connected to the pipe P2, the pipe P3, and the pipe TB. Figure 3 is a diagram showing the pipe TB.

[0022] The pipe TB has a double pipe structure and includes an inner flow path IP and an outer flow path OP. A first end of the pipe TB is connected to the branch valve 8, and a second end of the pipe TB is disposed in the hollow portion of the support member 17.

[0023] Liquid hydrogen flows through the inner flow path IP from the branch valve 8. Hydrogen gas flows through the outer flow path OP from the hollow portion of the support material 17. The reason for this flow is to suppress heat penetration into the liquid hydrogen, since the temperature of liquid hydrogen is lower than that of hydrogen gas.

[0024] The branch valve 8 allows liquid hydrogen sent from the liquid hydrogen supply valve 7 through P2 to flow into a flow path IP inside the pipe TB. The branch valve 8 also allows hydrogen gas sent through a flow path OP outside the pipe TB to flow into a pipe P3.

[0025] Hydrogen gas is sealed in the hydrogen gas container 6. Because the specific gravity of hydrogen is approximately 0.07 times that of air, the windage loss of the rotor 4 can be reduced to approximately one-tenth, thereby improving the efficiency of the superconducting generator SCG. In addition, the specific heat of hydrogen is approximately 14 times that of air, and its thermal conductivity is also high, improving the cooling efficiency of the armature 3. If the inside of the hydrogen gas container 6 is evacuated, the windage loss of the rotor 4 can be reduced, but the thermal conductivity is extremely poor, making it impossible to remove the heat generated by the armature 3, which could result in poor insulation or broken wires.

[0026] Inside the hydrogen gas container 6, the heat generated by the armature 3 is removed by hydrogen gas. The hydrogen gas supplied from the rotor 4 is at a low temperature, and its cold energy is utilized to absorb the heat generated by the armature 3. Because the hydrogen gas exhausted from the hydrogen gas container 6 has absorbed the heat generated by the armature 3, the temperature of the hydrogen gas exhausted from the exhaust port 10 (second temperature) is higher than the temperature of the low-temperature hydrogen gas supplied from the gas inlet 9 (first temperature). This allows the heat generated by the armature 3 to be recovered by hydrogen gas, thereby reducing the energy required to cool the armature 3. This contributes to energy savings and a lighter weight for the superconducting generator SCG.

[0027] 1, the hydrogen gas turbine 5 is driven by hydrogen gas sent through the exhaust port 10 and the pipe P4 as fuel. The rotor 4 is rotated by the power generated by the hydrogen gas turbine 5.

[0028] In this embodiment, the rotation axis R1 of the rotor 4 and the rotation axis R2 of the hydrogen gas turbine 5 are the same. Therefore, the rotation speed of the rotor 4 and the rotation speed of the hydrogen gas turbine 5 are the same.

[0029] According to this embodiment, by supplying liquid hydrogen to the rotor 4 containing the high-temperature superconducting coil 15, copper loss in the coil can be reduced compared to a general rotating electric machine, and power consumption can therefore be reduced.

[0030] Furthermore, by sealing the low-temperature hydrogen gas exhausted from the rotor 4 in the hydrogen gas container 6, it is possible to recover the heat generated by the armature 3. This eliminates the need for a hydrogen gas cooler, which is required in general rotating electrical machines, and makes it possible to reduce power consumption.

[0031] Furthermore, since hydrogen gas is sealed in the hydrogen gas container 6 that houses the rotor 4, windage loss of the rotor 4 can be suppressed, and the rotor 4 can be rotated stably.

[0032] Second Embodiment Fig. 4 is a diagram showing the configuration of a superconducting rotating electric machine system according to a second embodiment.

[0033] The superconducting rotating electric machine system of the second embodiment differs from the superconducting rotating electric machine system of the first embodiment in that the superconducting rotating electric machine system of the second embodiment includes a clutch 42 .

[0034] The clutch 42 is connected to the rotating shaft of the rotor 4 and the rotating shaft of the hydrogen gas turbine 5. The clutch 42 transmits or blocks the rotational force of the rotating shaft R2 of the hydrogen gas turbine 5 to the rotating shaft R1 of the rotor 4.

[0035] By switching between the presence or absence of grid connection between the rotor 4 and the hydrogen gas turbine 5 using the clutch 42, the superconducting generator SCG can function not only as a generator but also as a synchronous phase modifier.

[0036] When the clutch 42 cuts off the connection between the rotor 4 and the hydrogen gas turbine 5 and the armature 3 is connected to the power grid, the rotor 4 rotates in response to the varying magnetic field from the armature 3, causing the superconducting generator SCG to function as a synchronous phase modifier. In this case, the superconducting rotating electric machine system is in a state of providing inertial force to the power grid.

[0037] Therefore, when the demand for power is low and power generation is not necessary, the superconducting generator SCG can be operated as a synchronous phase modifier. As a result, the superconducting generator SCG can provide inertial force instead of active power, thereby improving the power quality.

[0038] Embodiment 3 In the first and second embodiments, the rotational axis of the rotor 4 and the rotational axis of the hydrogen gas turbine 5 are the same, so the rotational speed of the hydrogen gas turbine 5 and the rotational speed of the rotor 4 are the same.

[0039] Since the rotating shaft of the rotor 4 and the rotating shaft of the hydrogen gas turbine 5 are the same, there is no need to use a gear such as a reducer, which is advantageous in terms of strength and maintenance. This is particularly effective for large generators of 100 MW or more.

[0040] 5 is a diagram showing the configuration of a superconducting rotating electric machine system according to embodiment 3. The superconducting rotating electric machine system according to embodiment 3 differs from the superconducting rotating electric machine system according to embodiment 1 in that the superconducting rotating electric machine system according to embodiment 3 includes a reducer 45.

[0041] The reducer 45 is connected to the rotational axis R1 of the rotor 4 and the rotational axis R2 of the hydrogen gas turbine 5. The rotational axis R1 of the rotor 4 and the rotational axis R2 of the hydrogen gas turbine 5 are not the same. The reducer 45 transmits a low rotational speed, which is a reduction of the high rotational speed of the rotational axis R2 of the hydrogen gas turbine 5, to the rotational axis R1 of the rotor 4. This makes it possible to make the rotational speed of the rotor 4 lower than the rotational speed of the hydrogen gas turbine 5. This embodiment is effective for small generators such as private power generators.

[0042] Fourth Embodiment Fig. 6 is a diagram showing the configuration of a superconducting rotating electric machine system according to a fourth embodiment.

[0043] The superconducting rotating electric machine system of the fourth embodiment differs from the superconducting rotating electric machine system of the first embodiment in that the superconducting rotating electric machine system of the fourth embodiment includes a hydrogen gas tank 43 .

[0044] A hydrogen gas tank 43 is installed between the exhaust port 10 of the hydrogen gas container 6 and the hydrogen gas turbine 5. The exhaust port 10 of the hydrogen gas container 6 is connected to an air inlet 81 of the hydrogen gas tank 43 by a pipe P5. The exhaust port 82 of the hydrogen gas tank 43 is connected to the hydrogen gas turbine 5 by a pipe P6.

[0045] The hydrogen gas tank 43 stores hydrogen gas. The amount of hydrogen gas stored in the hydrogen gas tank 43 can be adjusted.

[0046] The superconducting rotating electric machine system of this embodiment assumes that the hydrogen gas turbine 5 operates intermittently rather than in base load operation (steady operation). The control circuit can control the hydrogen gas turbine 5 to operate and stop. When the amount of hydrogen gas discharged from the superconducting generator SCG is greater than the amount of hydrogen gas intake air of the hydrogen gas turbine 5, excessive hydrogen gas is supplied to the hydrogen gas turbine 5. As a result, the combustion efficiency of the hydrogen gas turbine 5 deteriorates and blade damage occurs due to a pressure increase. On the other hand, when the amount of hydrogen gas discharged from the superconducting generator SCG is smaller than the amount of hydrogen gas intake air of the hydrogen gas turbine 5, the combustion efficiency of the hydrogen gas turbine 5 does not deteriorate and blade damage due to a pressure increase does not occur. However, the rotational driving force (= torque) of the hydrogen gas turbine 5 decreases, which reduces the output of the superconducting generator SCG and degrades power quality.

[0047] In this embodiment, by adjusting the amount of hydrogen gas stored in the hydrogen gas tank 43, only an appropriate amount of hydrogen gas from the superconducting generator SCG can be supplied to the hydrogen gas turbine 5, thereby avoiding the above-mentioned problem.

[0048] Fifth Embodiment Fig. 7 is a diagram showing the configuration of a superconducting rotating electric machine system according to a fifth embodiment.

[0049] The superconducting rotating electric machine system of the fifth embodiment differs from the superconducting rotating electric machine system of the first embodiment in that the superconducting rotating electric machine system of the fifth embodiment includes a sealing valve 44 .

[0050] The sealing valve 44 is provided on a pipe P4 connecting the exhaust port 10 of the hydrogen gas container 6 and the hydrogen gas turbine 5.

[0051] When the superconducting generator SCG is used as a synchronous phase modifier, the hydrogen gas can be retained in the hydrogen gas container 6 by closing the sealing valve 44. Since no hydrogen gas is supplied to the hydrogen gas turbine 5, the hydrogen gas turbine 5 stops. Because the hydrogen gas is retained in the hydrogen gas container 6, windage loss during rotation of the rotor 4 can be reduced. As a result, a reduction in the power quality of the superconducting generator SCG can be avoided.

[0052] When the temperature of the hydrogen gas in the hydrogen gas container 6 becomes high, the sealing valve 44 may be opened to discharge the hydrogen gas from the hydrogen gas container 6 .

[0053] Modification 1: The hydrogen gas container 6 may be enlarged so that the rotor 4 can be entirely accommodated inside the hydrogen gas container 6 .

[0054] Modification 2: The exhaust port 10 of the hydrogen gas container 6 may be arranged at a position farthest from the inlet port 9 of the hydrogen gas container 6. This allows a temperature gradient to be set within the hydrogen gas container 6 so that the armature 3 can be easily cooled.

[0055] Modification 3. Any two or more of the above-described embodiments 1 to 5 can be combined.

[0056] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0057] 2 liquid hydrogen tank, 3 armature, 4 rotor, 5 hydrogen gas turbine, 6 hydrogen gas container, 7 liquid hydrogen supply valve, 8 branch valve, 9, 81 air inlet, 10, 82 exhaust port, 12 magnetic shield, 14 cryostat, 15 high-temperature superconducting coil, 16 low-temperature damper, 17 support material, 42 clutch, 43 hydrogen gas tank, 44 sealing valve, 45 reducer, IP, OP flow path, P1, P2, P3, P4, P5, P6 pipe, R1, R2 rotating shaft, SCG superconducting generator.

Claims

1. A superconducting generator comprising a rotor including a high-temperature superconducting coil cooled by liquid hydrogen, a stator, and a hydrogen gas container that houses the stator and the high-temperature superconducting coil and that cools the stator with hydrogen gas obtained by changing the liquid hydrogen by cooling the high-temperature superconducting coil.

2. The superconducting generator according to claim 1, wherein the rotor includes a hollow support member that supports the high-temperature superconducting coil and stores the liquid hydrogen.

3. The superconducting generator according to claim 2, wherein the liquid hydrogen is supplied to a hollow portion inside the support member, and the hydrogen gas is discharged from the hollow portion.

4. The superconducting generator according to claim 3, wherein after the hydrogen gas is discharged from the hollow portion to the outside of the hydrogen gas container through a first pipe, the hydrogen gas is supplied to an air supply port of the hydrogen gas container through a second pipe.

5. The superconducting generator according to claim 4, wherein the hydrogen gas flows into the hydrogen gas container at a first temperature from the air supply port of the hydrogen gas container, and the hydrogen gas is exhausted from an exhaust port of the hydrogen gas container at a second temperature higher than the first temperature.

6. The superconducting generator according to any one of claims 2 to 5, wherein the rotor includes a cryogenic container that houses the high-temperature superconducting coil and the support member.

7. A superconducting rotating electrical machine system comprising a liquid hydrogen tank that stores liquid hydrogen, a liquid hydrogen supply valve connected to the liquid hydrogen tank for supplying the liquid hydrogen to the rotor, the superconducting generator according to any one of claims 1 to 6, and a hydrogen gas turbine driven by using the hydrogen gas discharged from the hydrogen gas container as fuel.

8. The superconducting rotating electrical machine system according to claim 7, wherein a rotation axis of the rotor and a rotation axis of the hydrogen gas turbine are the same.

9. The superconducting rotating electrical machine system according to claim 7 or 8, comprising a clutch for switching the presence or absence of connection between the rotor and the hydrogen gas turbine.

10. The superconducting rotating electrical machine system according to claim 7, comprising a speed reducer connected to a rotation axis of the rotor and a rotation axis of the hydrogen gas turbine.

11. The superconducting rotating electrical machine system according to any one of claims 7 to 10, comprising a hydrogen gas tank disposed between an exhaust port of the hydrogen gas container and the hydrogen gas turbine.

12. The superconducting rotating electrical machine system according to any one of claims 7 to 10, comprising a sealing valve connected to the exhaust port of the hydrogen gas container.

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