Superconducting power generation system

Abstract

This superconducting power generation system comprises: a hydrogen gas turbine (4); a superconducting generator (2) to which liquid hydrogen is supplied and which is driven by the hydrogen gas turbine (4); and a refrigeration device (3) for cooling and thus re-liquefying the hydrogen gas which has resulted from the liquid hydrogen supplied to the superconducting generator (2) being vaporized and flowing out from the superconducting generator (2).

Description

Superconducting power generation system

[0001] The present disclosure relates to superconducting power generation systems.

[0002] In recent years, generators have been developed that include rotors that use superconducting wires as rotating field windings. Superconducting field windings must be cooled to below their transition temperature to maintain their superconducting state. Liquid hydrogen or other refrigerants are used for cooling. After cooling the rotor containing the field winding, the liquid refrigerant vaporizes due to heat intrusion, such as conductive or radiative heat transfer. The vaporized refrigerant cools the surrounding armature and other components, and is then guided outside the generator through a connecting pipe or exhaust hole for recovery (see, for example, Non-Patent Document 1).

[0003] Yasuyuki Shirai and Masahiro Shiotsu (Kyoto University) "Development of Liquid Hydrogen-Cooled Superconducting Energy Devices," Cryogenic Engineering Vol. 55 No. 1, 2020

[0004] However, in Non-Patent Document 1, there is a problem in that a large amount of liquid hydrogen is supplied to cool the generator, because the excess hydrogen gas flowing out from the superconducting generator in excess of the amount used by the hydrogen gas turbine is discarded.

[0005] Therefore, an object of the present disclosure is to provide a superconducting power generation system that can reduce the amount of liquid hydrogen supplied to cool the generator.

[0006] The superconducting power generation system of the present disclosure includes a hydrogen gas turbine, a superconducting generator that is supplied with liquid hydrogen and driven by the hydrogen gas turbine, and a refrigeration device that vaporizes the liquid hydrogen supplied to the superconducting generator and cools the hydrogen gas that flows out of the superconducting generator to re-liquefy it.

[0007] According to the present disclosure, the amount of liquid hydrogen supplied for cooling the generator can be reduced.

[0008] FIG. 1 is a diagram showing the configuration of a superconducting power generation system according to embodiment 1. FIG. 2 is a flowchart showing the control procedure of the superconducting power generation system according to embodiment 1. FIG. 3 is a diagram showing the configuration of a superconducting power generation system according to embodiment 2. FIG. 4 is a diagram showing the configuration of a superconducting power generation system according to embodiment 3. FIG. 5 is a flowchart showing the control procedure of the superconducting power generation system according to embodiment 4.

[0009] Hereinafter, embodiments will be described with reference to the drawings. Embodiment 1 Fig. 1 is a diagram showing the configuration of a superconducting power generation system according to a first embodiment.

[0010] The superconducting power generation system includes a liquid hydrogen storage unit 1, a superconducting generator 2, a magnetic refrigeration device 3, a hydrogen gas turbine 4, a hydrogen gasification mechanism 5, an evaporated hydrogen amount detection unit 6, a liquid hydrogen supply control valve 7, a hydrogen gas supply control valve 8, a control unit 11, and a drive unit 12.

[0011] The liquid hydrogen storage unit 1 is connected to a pipe P1 and a pipe P2. The liquid hydrogen supply control valve 7 has ports A1, A2, A3, A4, and A5. Port A1 is connected to the pipe P1. Port A2 is connected to the pipe P2. Port A3 is connected to the pipe P3. Port A4 is connected to the pipe P5. Port A5 is connected to the pipe P4.

[0012] The superconducting generator 2 is connected to the pipes P3 and P7, and the magnetic refrigerator 3 is connected to the pipes P4 and P6.

[0013] The hydrogen gasification mechanism 5 is provided on the pipe P5. The evaporated hydrogen amount detection unit 6 is provided on the pipe P7.

[0014] The hydrogen gas supply control valve 8 has ports B1, B2, and B3. Port B1 is connected to a pipe P7. Port B2 is connected to a pipe P6. Port B3 is connected to a pipe P8. Pipe P5 is connected to pipe P8.

[0015] The hydrogen gas turbine 4 is connected to the pipe P8. The liquid hydrogen storage unit 1 stores liquid hydrogen.

[0016] The hydrogen gas turbine 4 is driven by hydrogen gas supplied through pipe P8. The superconducting generator 2 converts the power generated by the hydrogen gas turbine 4 into electric power. The superconducting generator 2 includes a superconducting conductor. The superconducting conductor is maintained in a superconducting state by utilizing the cold heat of liquid hydrogen (boiling point approximately -20K) supplied through pipe P3. The liquid hydrogen vaporizes within the superconducting generator 2, and hydrogen gas flows into pipe P7. The superconducting generator 2 has a stator and a rotor (not shown). Either or both of the stator and rotor are made of a superconductor. The magnetic refrigeration unit 3 cools the hydrogen gas supplied through pipe P6 and releases the liquid hydrogen into pipe P4.

[0017] The liquid hydrogen supply control valve 7 supplies liquid hydrogen supplied from the liquid hydrogen storage unit 1 to either or both of the superconducting generator 2 and the hydrogen gas turbine 4. Liquid hydrogen sent from the liquid hydrogen storage unit 1 through pipe P1 flows into port A1 of the liquid hydrogen supply control valve 7. The liquid hydrogen that flows in from port A1 flows out from either or both of port A3 and port A4. The control unit 11 can control the rate at which liquid hydrogen flows out to ports A3 and A4. Liquid hydrogen that flows out from the magnetic refrigeration device 3 flows into port A5 of the liquid hydrogen supply control valve 7. The liquid hydrogen that flows in to port A5 flows out from either or both of port A2 and port A3. The control unit 11 can control the rate at which liquid hydrogen flows out to ports A3 and A4.

[0018] The hydrogen gas supply control valve 8 supplies the hydrogen gas flowing out from the superconducting generator 2 to either or both of the magnetic refrigeration device 3 and the hydrogen gas turbine 4. Specifically, the hydrogen gas flowing out from the superconducting generator 2 flows into port B1 of the hydrogen gas supply control valve 8. The hydrogen gas flowing in from port B1 flows out from either or both of port B2 and port B3. The control unit 11 controls the ratio of the hydrogen gas flowing out to ports B2 and B3.

[0019] The hydrogen gasification mechanism 5 converts the liquid hydrogen discharged from the port A4 and sent through the pipe P5 into hydrogen gas. The hydrogen gasification mechanism 5 may be configured, for example, by a heater. The hydrogen gas is sent to the hydrogen gas turbine 4 via the pipe P5 and the pipe P8.

[0020] The evaporated hydrogen amount detector 6 detects the amount of hydrogen gas that has flowed out from the superconducting generator 2. The evaporated hydrogen amount detector 6 can be configured by, for example, a gas sensor.

[0021] A typical example of the flow of hydrogen will be described below. Liquid hydrogen is supplied from the liquid hydrogen storage unit 1 to the superconducting generator 2 via the liquid hydrogen supply control valve 7. After cooling the superconducting generator 2, the liquid hydrogen evaporates and becomes hydrogen gas, which is then discharged outside the superconducting generator 2.

[0022] The hydrogen gas passes through hydrogen gas supply control valve 8, and a portion of it is combusted in hydrogen gas turbine 4 to power superconducting generator 2. The remaining hydrogen gas is cooled and liquefied by passing through magnetic refrigeration device 3. The liquid hydrogen passes through liquid hydrogen supply control valve 7 and splits into two paths: one that returns to liquid hydrogen storage unit 1 and one that flows to superconducting generator 2 for cooling again.

[0023] The control unit 11 controls the superconducting generator 2 , the magnetic refrigeration device 3 , the liquid hydrogen supply control valve 7 , the hydrogen gas supply control valve 8 , the hydrogen gasification mechanism 5 , the evaporated hydrogen amount detection unit 6 , and the hydrogen gas turbine 4 .

[0024] The driving unit 12 drives the superconducting generator 2 and the magnetic refrigeration device 3. Fig. 2 is a flowchart showing the control procedure of the superconducting power generation system of the first embodiment.

[0025] In step S101, the control unit 11 controls the liquid hydrogen supply control valve 7 so that liquid hydrogen that has flowed into port A1 of the liquid hydrogen supply control valve 7 flows out from port A3, and liquid hydrogen that has flowed into port A5 flows out from ports A2 and A3. As a result, liquid hydrogen that flows out from the liquid hydrogen storage unit 1 is supplied to the superconducting generator 2. Liquid hydrogen that flows out from the magnetic refrigeration device 3 is supplied to the superconducting generator 2 and the liquid hydrogen storage unit 1. The control unit 11 may also control the proportion of liquid hydrogen that flows out from port A2 and port A3. The control unit 11 may also control the liquid hydrogen to flow out from only one of port A2 and port A3.

[0026] In step S102, the control unit 11 acquires the power generation demand from the outside. In step S103, the control unit 11 acquires the amount of hydrogen gas flowing out from the superconducting generator 2 detected by the evaporated hydrogen amount detection unit 6.

[0027] In step S104, if power generation is stopped due to an excess supply of power or the like, or if the superconducting generator 2 is used as a synchronous phase modifier without being connected to the hydrogen gas turbine 4, the process proceeds to step S105.

[0028] In step S105, the control unit 11 controls the hydrogen gas supply control valve 8 so that the hydrogen gas that has flowed into port B1 of the hydrogen gas supply control valve 8 flows out from port B2. This stops the hydrogen gas turbine 4, and the superconducting generator 2, which has lost power from the hydrogen gas turbine 4, stops. The hydrogen gas that flows out from port B2 and flows into the magnetic refrigeration device 3 is cooled and liquefied as it passes through the magnetic refrigeration device 3, converting it into liquid hydrogen. The liquid hydrogen flows into port A5 of the liquid hydrogen supply control valve 7. A portion of the liquid hydrogen that flows into port A5 is sent to the liquid hydrogen storage unit 1 via port A2, and the remainder is sent to the superconducting generator 2 via port A3. Even though the superconducting generator 2 has stopped generating power, liquid hydrogen flows into the superconducting generator 2 and is cooled by the liquid hydrogen. Once the superconducting generator 2 returns to room temperature, it takes time for it to cool down again and resume operation. By continuing to cool the superconducting generator 2 with liquid hydrogen even when the generator 2 has stopped generating power, the time until the generator can be restarted can be shortened.

[0029] In step S106, if the amount of hydrogen gas detected by the evaporated hydrogen amount detection unit 6 is greater than the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of electricity, the process proceeds to step S107. If the amount of hydrogen gas detected by the evaporated hydrogen amount detection unit 6 is equal to or less than the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of electricity, the process proceeds to step S108. The amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of electricity can be identified, for example, using a table that defines the correspondence between the amount of electricity generated and the amount of hydrogen gas required to generate that amount of electricity.

[0030] In step S107, the control unit 11 controls the hydrogen gas supply control valve 8 so that the hydrogen gas that has flowed into port B1 of the hydrogen gas supply control valve 8 flows out from ports B2 and B3. This causes the hydrogen gas to be sent to the magnetic refrigeration device 3 and the hydrogen gas turbine 4. The hydrogen gas that has flowed into the magnetic refrigeration device 3 is cooled and liquefied as it passes through the magnetic refrigeration device 3, thereby changing into liquid hydrogen. The control unit 11 may control the rate at which the hydrogen gas flows out from ports B2 and B3 in accordance with the difference between the amount of hydrogen gas detected by the evaporated hydrogen amount detection unit 6 and the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of power. The control unit 11 may increase the amount of hydrogen gas that flows out from port B2 as the difference increases.

[0031] In step S108, the control unit 11 controls the hydrogen gas supply control valve 8 so that the hydrogen gas that has flowed into port B1 of the hydrogen gas supply control valve 8 flows out from port B3. As a result, the hydrogen gas is sent to the hydrogen gas turbine 4.

[0032] In step S109, if the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of power is still insufficient, the process proceeds to step S110.

[0033] In step S110, the control unit 11 controls the liquid hydrogen supply control valve 7 so that the liquid hydrogen that has flowed into port A1 of the liquid hydrogen supply control valve 7 flows out from ports A3 and A4.

[0034] In step S111, the control unit 11 turns on the hydrogen gasification mechanism 5. As a result, the liquid hydrogen flowing out from the port A4 of the liquid hydrogen supply control valve 7 is converted into hydrogen gas and sent to the hydrogen gas turbine 4.

[0035] According to this embodiment, hydrogen gas is liquefied in the magnetic refrigeration unit 3, and the re-liquefied hydrogen is supplied again to at least one of the liquid hydrogen storage unit 1 and the superconducting generator 2. After using liquid hydrogen to cool the superconducting generator 2, the hydrogen gas flowing out from the superconducting generator 2 is re-liquefied by the magnetic refrigeration unit 3, thereby reducing the amount of liquid hydrogen consumed. By adjusting the amount of re-liquefied liquid hydrogen using the hydrogen gas supply control valve 8, an optimal re-liquefaction amount that reflects the balance of supply and demand of liquid hydrogen can be achieved, making liquid hydrogen use more efficient. In the systems described in prior literature, the excess hydrogen gas flowing out from the superconducting generator that exceeds the amount used by the hydrogen gas turbine was discarded, but according to this embodiment, the excess hydrogen gas can be re-liquefied in the magnetic refrigeration unit and reused.

[0036] Second Embodiment Fig. 3 is a diagram showing the configuration of a superconducting power generation system according to a second embodiment.

[0037] The superconducting power generation system of the second embodiment differs from the superconducting power generation system of the first embodiment in that the superconducting power generation system of the second embodiment includes a superconducting generator 2A instead of the superconducting generator 2.

[0038] The superconducting generator 2A includes a stator 13 and a superconducting rotor 14. The superconducting rotor 14 is made of a high-temperature superconductor.

[0039] The stator 13 is made of a general conductor. If the stator 13 is made of a superconductor, the stator 13 may not be able to maintain its superconducting state due to the AC current generated in the stator 13. Therefore, the stator 13 is made of a general conductor.

[0040] The liquid hydrogen that flows into the superconducting generator 2A cools the high-temperature superconductor that forms the superconducting rotor 14, allowing the high-temperature superconductor to maintain its superconducting state. The liquid hydrogen then evaporates, becoming low-temperature hydrogen gas (above 20 K and below room temperature), which flows to and cools the stator 13. The hydrogen gas that has cooled the stator 13 then rises in temperature and flows out of the superconducting generator 2A.

[0041] The stator 13 may also be made of a high-temperature superconductor. Third Embodiment Fig. 4 is a diagram showing the configuration of a superconducting power generation system according to a third embodiment.

[0042] The superconducting power generation system of embodiment 3 differs from the superconducting power generation system of embodiment 1 in that the superconducting power generation system of embodiment 3 is equipped with a magnetic refrigeration unit 3A instead of the magnetic refrigeration unit 3, and is equipped with a liquid hydrogen supply control valve 7A and pipes P11, P12, and P13.

[0043] The magnetic refrigeration apparatus 3A is equipped with a magnetocaloric mechanism 15 and a magnetic field generator 16. The liquid hydrogen supply control valve 7A is equipped with ports C1, C2, and C3. Port C1 is connected to pipe P11. Pipe P11 is connected to port A3 of the liquid hydrogen supply control valve 7. Port C2 is connected to pipe P3. Port C3 is connected to pipe P12. Pipe P4 is connected to the magnetocaloric mechanism 15 of the magnetic refrigeration apparatus 3A. Pipe P12 is connected to the magnetic field generator 16 of the magnetic refrigeration apparatus 3A. Pipe P13 is connected to the magnetic field generator 16 of the magnetic refrigeration apparatus 3A and pipe P7.

[0044] Liquid hydrogen is supplied to the liquid hydrogen supply control valve 7 from the magnetic calorific mechanism 15 of the magnetic refrigeration device 3 and the liquid hydrogen storage unit 1. The liquid hydrogen supply control valve 7 adjusts the amount of liquid hydrogen supplied to the hydrogen gas turbine 4 via the superconducting generator 2, the magnetic field generating device 16 of the magnetic refrigeration device 3A, and the hydrogen gasification mechanism 5. Liquid hydrogen sent from the liquid hydrogen storage unit 1 via pipe P1 flows into port A1 of the liquid hydrogen supply control valve 7. The liquid hydrogen that flows in from port A1 flows out from either or both of ports A3 and A4. During liquid hydrogen heating operation of the magnetic refrigeration device 3A, liquid hydrogen also flows out from port A5 and is sent to the magnetocaloric mechanism 15 through pipe P5. The control unit 11 can control the ratio of liquid hydrogen flowing into ports A3, A4, and A5. During hydrogen gas cooling operation of the magnetic refrigeration device 3A, liquid hydrogen sent from the magnetocaloric mechanism 15 via pipe P4 flows into port A5 of the liquid hydrogen supply control valve 7. Liquid hydrogen flowing in from port A5 flows out from either or both of port A2 and port A3. The control unit 11 can control the ratio of liquid hydrogen flowing out to ports A2 and A3.

[0045] The liquid hydrogen supply control valve 7A adjusts the amount of liquid hydrogen supplied to the superconducting generator 2 and the magnetic refrigeration device 3A. Liquid hydrogen flows into port C1 from port A3 of the liquid hydrogen supply control valve 7 through pipe P11. The liquid hydrogen that flows into port C1 flows out from ports C2 and C3. The liquid hydrogen that flows out from port C2 is sent to the superconducting generator 2 through pipe P3. The liquid hydrogen that flows out from port C3 is sent to the magnetic field generator 16 through pipe P12. The control unit 11 can control the ratio of liquid hydrogen that flows out to ports C2 and C3.

[0046] The magnetic field generator 16 is formed of a superconducting coil made of high-temperature superconductor. To maintain the superconducting state of the high-temperature superconductor, the magnetic field generator 16 is cooled by liquid hydrogen sent via ports A3, C1, C3, and pipe P12. The liquid hydrogen evaporates and becomes hydrogen gas, which flows to port B1 of the hydrogen gas supply control valve 8 via pipes P13 and P7.

[0047] The magnetocaloric mechanism 15 has a first port PV1 and a second port PV2. The first port PV1 is connected to a port A5 of the liquid hydrogen supply control valve 7 via a pipe P4. The second port PV2 is connected to a port B2 of the hydrogen gas supply control valve 8 via a pipe P6. The magnetocaloric mechanism 15 has a magnetocaloric material.

[0048] When the required amount of hydrogen gas calculated from the power generation demand is insufficient, the control unit 11 selects liquid hydrogen heating operation (heat generation operation) by the magnetic refrigeration unit 3A. During heating operation of the magnetic refrigeration unit 3A, the control unit 11 magnetizes the magnetic field applied to the magnetocaloric mechanism 15. During heating operation of the magnetic refrigeration unit 3A, the control unit 11 controls so that liquid hydrogen flows into the magnetocaloric mechanism 15 from a first port PV1 of the magnetocaloric mechanism 15 and the heated and evaporated hydrogen gas flows out from a second port PV2 of the magnetocaloric mechanism 15. This increases the amount of hydrogen gas heading toward the hydrogen gas turbine 4.

[0049] When the required amount of hydrogen gas calculated from the power generation demand is in excess, the control unit 11 selects cooling operation (heat absorption operation) of the hydrogen gas by the magnetic refrigeration unit 3A. During cooling operation of the magnetic refrigeration unit 3A, the control unit 11 demagnetizes the magnetic field applied to the magnetocaloric mechanism 15. During cooling operation of the magnetic refrigeration unit 3A, the control unit 11 controls so that hydrogen gas flows into the magnetocaloric mechanism 15 from the second port PV2 of the magnetocaloric mechanism 15 and the liquefied liquid hydrogen flows out from the first port PV1 of the magnetocaloric mechanism 15. This allows the excess hydrogen gas to be re-liquefied into liquid hydrogen and returned to the liquid hydrogen storage unit 1.

[0050] The magnetic field generating device 16 can increase or decrease the magnetic field applied to the magnetocaloric mechanism 15 by changing the current flowing through the coil. Alternatively, the magnetic field applied to the magnetocaloric mechanism 15 may be increased or decreased by moving the magnetocaloric mechanism 15.

[0051] FIG. 5 is a flowchart showing the control procedure of the superconducting power generation system according to the third embodiment.

[0052] In step S201, the control unit 11 selects the cooling operation of the magnetic refrigeration device 3A as the initial state.

[0053] In step S202, the control unit 11 controls the liquid hydrogen supply control valve 7 so that liquid hydrogen that has flowed into port A1 of the liquid hydrogen supply control valve 7 flows out from port A3, and liquid hydrogen that has flowed into port A5 flows out from ports A2 and A3. As a result, liquid hydrogen that flows out from the liquid hydrogen storage unit 1 is supplied to the liquid hydrogen supply control valve 7A. Liquid hydrogen that flows out from the magnetic refrigeration device 3A is supplied to the liquid hydrogen supply control valve 7A and the liquid hydrogen storage unit 1. The control unit 11 may also control the ratio of liquid hydrogen that flows out from ports A2 and A3. The control unit 11 may also control the liquid hydrogen to flow out from only one of ports A2 and A3.

[0054] In step S203, the control unit 11 controls the liquid hydrogen supply control valve 7A so that the liquid hydrogen that has flowed into port C1 of the liquid hydrogen supply control valve 7A flows out from ports C2 and C3. As a result, the liquid hydrogen flowing from the liquid hydrogen supply control valve 7A is supplied to the superconducting generator 2 and the magnetic field generating device 16.

[0055] In step S204, the control unit 11 acquires the power generation demand from the outside. In step S205, the control unit 11 acquires the amount of hydrogen gas flowing out from the superconducting generator 2 detected by the evaporated hydrogen amount detection unit 6.

[0056] In step S206, if power generation is stopped due to an excess supply of power or the like, or if the superconducting generator 2 is used as a synchronous phase modifier without being connected to the hydrogen gas turbine 4, the process proceeds to step S207.

[0057] In step S207, the control unit 11 controls the hydrogen gas supply control valve 8 so that the hydrogen gas that has flowed into port B1 of the hydrogen gas supply control valve 8 flows out from port B2. This stops the hydrogen gas turbine 4, and the superconducting generator 2, which has lost power from the hydrogen gas turbine 4, stops. The hydrogen gas that flows out from port B2 and flows into the magnetic calorific mechanism 15 of the magnetic refrigeration device 3A, is cooled and liquefied as it passes through the magnetic refrigeration device 3, and is converted into liquid hydrogen. The liquid hydrogen flows into port A5 of the liquid hydrogen supply control valve 7. A portion of the liquid hydrogen that flows into port A5 is sent to the liquid hydrogen storage unit 1 via port A2, and the remainder of the liquid hydrogen is sent to port C1 of the liquid hydrogen supply control valve 7A via port A3. The liquid hydrogen that flows into port C1 is sent to the superconducting generator 2 via port C2 and to the magnetic field generating device 16 via port C3. Even though the superconducting generator 2 has stopped generating power, liquid hydrogen flows into the superconducting generator 2 and the superconducting generator 2 is cooled by the liquid hydrogen. Once the superconducting generator 2 reaches room temperature, it takes time for it to cool down again and restart. By continuing to cool the superconducting generator 2 with liquid hydrogen even when power generation has stopped, the time until the superconducting generator 2 can be restarted can be shortened.

[0058] In step S208, if the amount of hydrogen gas detected by the evaporated hydrogen amount detection unit 6 is greater than the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of electricity, the process proceeds to step S209. If the amount of hydrogen gas detected by the evaporated hydrogen amount detection unit 6 is equal to or less than the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of electricity, the process proceeds to step S210. The amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of electricity can be identified, for example, using a table that defines the correspondence between the amount of electricity generated and the amount of hydrogen gas required to generate that amount of electricity.

[0059] In step S209, the control unit 11 controls the hydrogen gas supply control valve 8 so that the hydrogen gas that has flowed into port B1 of the hydrogen gas supply control valve 8 flows out from ports B2 and B3. This causes the hydrogen gas to be sent to the magnetocaloric mechanism 15 of the magnetic refrigeration device 3A and the hydrogen gas turbine 4. The hydrogen gas that has flowed into the magnetocaloric mechanism 15 is cooled and liquefied as it passes through the magnetocaloric mechanism 15, thereby changing into liquid hydrogen. The control unit 11 may control the rate at which the hydrogen gas flows out from ports B2 and B3 in accordance with the difference between the amount of hydrogen gas detected by the evaporated hydrogen amount detection unit 6 and the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of power. The control unit 11 may increase the amount of hydrogen gas flowing out from port B2 as the difference increases.

[0060] In step S210, the control unit 11 selects heating operation of the magnetic refrigeration unit 3A. In step S211, the control unit 11 controls the liquid hydrogen supply control valve 7 so that liquid hydrogen that has flowed into port A1 of the liquid hydrogen supply control valve 7 flows out from ports A3 and A5. The liquid hydrogen that flows out of the liquid hydrogen storage unit 1 is supplied to the liquid hydrogen supply control valve 7A and the magnetocaloric mechanism 15. The liquid hydrogen that flows into the first port PV1 of the magnetocaloric mechanism 15 is heated and vaporized into hydrogen gas, which flows out from the second port PV2 of the magnetocaloric mechanism 15. The hydrogen gas that flows out from the second port PV2 flows through the pipe P6 into port B2 of the hydrogen gas supply control valve 8.

[0061] In step S212, the control unit 11 controls the hydrogen gas supply control valve 8 so that the hydrogen gas that has flowed into port B1 of the hydrogen gas supply control valve 8 flows out from port B3, and the hydrogen gas that has flowed into port B2 flows out from port B3. As a result, the hydrogen gas is sent to the hydrogen gas turbine 4.

[0062] In step S213, if the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of power is still insufficient, the process proceeds to step S214.

[0063] In step S214, the control unit 11 controls the liquid hydrogen supply control valve 7 so that the liquid hydrogen that has flowed into port A1 of the liquid hydrogen supply control valve 7 flows out from ports A3, A4, and A5.

[0064] In step S215, the control unit 11 turns on the hydrogen gasification mechanism 5. As a result, the liquid hydrogen flowing out from port A4 of the liquid hydrogen supply control valve 7 is converted into hydrogen gas and sent to the hydrogen gas turbine 4.

[0065] Fourth Embodiment FIG. 6 is a diagram showing the configuration of a superconducting power generation system according to a fourth embodiment.

[0066] The superconducting power generation system of embodiment 4 differs from the superconducting power generation system of embodiment 3 in that the superconducting power generation system of embodiment 4 is equipped with hydrogen gas supply control valves 8A and 8B instead of hydrogen gas supply control valve 8, and is equipped with liquid hydrogen supply control valve 7B and pipes P14, P15, P16, and P17.

[0067] The liquid hydrogen supply control valve 7B includes ports D1, D2, and D3. Port D1 is connected to a pipe P14. Port D2 is connected to a pipe P15. Pipe P15 is connected to a first port PV1 of the magnetocaloric mechanism 15. Port D3 is connected to a pipe P5.

[0068] The hydrogen gas supply control valve 8A includes ports E1, E2, E3, and E4. Port E1 is connected to pipe P7. Port E2 is connected to pipe P6. Port E3 is connected to pipe P16. Pipe P16 is connected to a second port PV2 of the magnetocaloric mechanism 15. Port E4 is connected to pipe P17. Pipe P17 is connected to the hydrogen gas supply control valve 8B.

[0069] The hydrogen gas supply control valve 8B is connected to ports F1, F2, and F3. Port F1 is connected to pipe P17. Port F2 is connected to pipe P8. Port F3 is connected to pipe P5.

[0070] Liquid hydrogen flows into port D1 of liquid hydrogen supply control valve 7B from port A4 of liquid hydrogen supply control valve 7. The flowing-in liquid hydrogen flows out from either or both of port D2 and port D3. The liquid hydrogen flowing out from port D2 passes through pipe P15 and flows into first port PV1 of magnetocaloric mechanism 15. Hydrogen gas flows out from second port PV2 of magnetocaloric mechanism 15 and passes through pipe P16 and flows into port E3 of hydrogen gas supply control valve 8A. The control unit 11 can control the ratio of liquid hydrogen flowing into ports D2 and D3.

[0071] Port E1 of the hydrogen gas supply control valve 8A receives hydrogen gas flowing out from the superconducting generator 2 and the magnetic field generator 16. The hydrogen gas flowing in from port E1 flows out from port E4. During cooling operation of the magnetic refrigeration device 3A, the hydrogen gas flowing in from port E1 also flows out from port E2. The control unit 11 can control the ratio of hydrogen gas flowing into ports E2 and E4. The hydrogen gas flowing out from port E2 flows into the fourth port PV4 of the magnetocaloric mechanism 15. The hydrogen gas is cooled within the magnetocaloric mechanism 15, and liquid hydrogen flows out from the third port PV3 of the magnetocaloric mechanism 15. The liquid hydrogen flowing out from the third port PV3 flows through pipe P4 into port A5 of the liquid hydrogen supply control valve 7. During heating operation of the magnetic refrigeration device 3A, the hydrogen gas flowing out from the second port PV2 of the magnetocaloric mechanism 15 flows into port E3 through pipe P16. The hydrogen gas that has flowed into port E3 flows out from port E4, passes through pipe P17, and flows into port F1 of the hydrogen gas supply control valve 8B.

[0072] The hydrogen gas that flows into port F1 of the hydrogen gas supply control valve 8B flows out from port F2, and the hydrogen gas that flows into port F3 of the hydrogen gas supply control valve 8B flows out from port F2.

[0073] FIG. 7 is a flowchart showing the control procedure of the superconducting power generation system according to the fourth embodiment.

[0074] In step S301, the control unit 11 selects the cooling operation of the magnetic refrigeration device 3A as the initial state.

[0075] In step S302, the control unit 11 controls the liquid hydrogen supply control valve 7 so that liquid hydrogen that has flowed into port A1 of the liquid hydrogen supply control valve 7 flows out from port A3, and liquid hydrogen that has flowed into port A5 flows out from ports A2 and A3. As a result, liquid hydrogen that flows out from the liquid hydrogen storage unit 1 is supplied to the liquid hydrogen supply control valve 7A. Liquid hydrogen that flows out from the magnetic refrigeration device 3A is supplied to the liquid hydrogen supply control valve 7A and the liquid hydrogen storage unit 1. The control unit 11 may also control the ratio of liquid hydrogen that flows out from ports A2 and A3. The control unit 11 may also control the liquid hydrogen to flow out from only one of ports A2 and A3.

[0076] In step S303, the control unit 11 controls the liquid hydrogen supply control valve 7A so that the liquid hydrogen that has flowed into port C1 of the liquid hydrogen supply control valve 7A flows out from ports C2 and C3. As a result, the liquid hydrogen flowing from the liquid hydrogen supply control valve 7A is supplied to the superconducting generator 2 and the magnetic field generating device 16.

[0077] In step S304, the control unit 11 acquires the power generation demand from the outside. In step S305, the control unit 11 acquires the amount of hydrogen gas flowing out from the superconducting generator 2 detected by the evaporated hydrogen amount detection unit 6.

[0078] In step S306, if power generation is stopped due to an excess supply of power or the like, or if the superconducting generator 2 is used as a synchronous phase modifier without being connected to the hydrogen gas turbine 4, the process proceeds to step S307.

[0079] In step S307, the control unit 11 controls the hydrogen gas supply control valve 8A so that the hydrogen gas that has flowed into port E1 of the hydrogen gas supply control valve 8A flows out from port E2. This stops the hydrogen gas turbine 4, and the superconducting generator 2, which has lost power from the hydrogen gas turbine 4, stops. The hydrogen gas that flows out from port E2 and flows into the fourth port PV4 of the magnetocaloric mechanism 15 of the magnetic refrigeration device 3A, is cooled and liquefied as it passes through the magnetocaloric mechanism 15, and is converted into liquid hydrogen. The liquid hydrogen flows out from the third port PV3 of the magnetocaloric mechanism 15 and flows through pipe P4 into port A5 of the liquid hydrogen supply control valve 7. A portion of the liquid hydrogen that flows into port A5 is sent to the liquid hydrogen storage unit 1 via port A2, and the remainder of the liquid hydrogen is sent to the superconducting generator 2 via port A3. Even though the superconducting generator 2 has stopped generating power, liquid hydrogen flows into the superconducting generator 2, and the superconducting generator 2 is cooled by the liquid hydrogen. Once the superconducting generator 2 reaches room temperature, it takes time for it to cool down again and restart. By continuing to cool the superconducting generator 2 with liquid hydrogen even when power generation is stopped, the time until restarting can be shortened.

[0080] In step S308, if the amount of hydrogen gas detected by the evaporated hydrogen amount detection unit 6 is greater than the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of electricity, the process proceeds to step S309. If the amount of hydrogen gas detected by the evaporated hydrogen amount detection unit 6 is equal to or less than the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of electricity, the process proceeds to step S310. The amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of electricity can be identified, for example, using a table that defines the correspondence between the amount of electricity generated and the amount of hydrogen gas required to generate that amount of electricity.

[0081] In step S309, the control unit 11 controls the hydrogen gas supply control valve 8A so that the hydrogen gas that flows into port E1 of the hydrogen gas supply control valve 8A flows out from ports E2 and E4. This causes the hydrogen gas to be sent to the magnetocaloric mechanism 15 of the magnetic refrigeration device 3A and the hydrogen gas supply control valve 8B. The hydrogen gas that flows into the fourth port PV4 of the magnetocaloric mechanism 15 of the magnetic refrigeration device 3A is cooled and liquefied as it passes through the magnetocaloric mechanism 15, converting it into liquid hydrogen. The liquid hydrogen flows out from the third port PV3 of the magnetocaloric mechanism 15 and flows through pipe P4 into port A5 of the liquid hydrogen supply control valve 7. A portion of the liquid hydrogen that flows into port A5 is sent to the liquid hydrogen storage unit 1 via port A2, and the remainder is sent to port C1 of the liquid hydrogen supply control valve 7A via port A3. The liquid hydrogen that flows into port C1 is sent to the superconducting generator 2 via port C2 and to the magnetic field generating device 16 via port C3. The control unit 11 may control the rate at which hydrogen gas flows out from the port E2 and the port E4 in accordance with the difference between the amount of hydrogen gas detected by the evaporated hydrogen amount detection unit 6 and the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of power. The control unit 11 may increase the amount of hydrogen gas flowing out from the port E2 as the difference increases.

[0082] In step S310, the control unit 11 controls the hydrogen gas supply control valve 8A so that the hydrogen gas that has flowed into port F1 of the hydrogen gas supply control valve 8B flows out from port F2. As a result, the hydrogen gas is sent to the hydrogen gas turbine 4.

[0083] In step S311, the control unit 11 selects heating operation of the magnetic refrigeration unit 3A. In step S312, the control unit 11 controls the liquid hydrogen supply control valve 7 so that the liquid hydrogen that has flowed into port A1 of the liquid hydrogen supply control valve 7 flows out from ports A3 and A5. The liquid hydrogen that flows out from the liquid hydrogen storage unit 1 is supplied to the liquid hydrogen supply control valve 7A and the liquid hydrogen supply control valve 7A.

[0084] In step S313, the control unit 11 controls the liquid hydrogen supply control valve 7B so that the liquid hydrogen that has flowed into port D1 of the liquid hydrogen supply control valve 7B flows out from port D2. The liquid hydrogen that flows out from port D2 flows into the first port PV1 of the magnetocaloric mechanism 15. Inside the magnetocaloric mechanism 15, the liquid hydrogen is heated and vaporized into hydrogen gas, which flows out from the second port PV2 of the magnetocaloric mechanism 15. The hydrogen gas that flows out from the second port PV2 passes through the pipe P6 and flows into the port E3 of the hydrogen gas supply control valve 8A.

[0085] In step S314, the control unit 11 controls the hydrogen gas supply control valve 8A so that the hydrogen gas that has flowed into port E1 of the hydrogen gas supply control valve 8A flows out from port E4, and the hydrogen gas that has flowed into port E3 flows out from port E4, thereby sending hydrogen gas to port F1 of the hydrogen gas supply control valve 8B.

[0086] In step S315, the control unit 11 controls the hydrogen gas supply control valve 8B so that the hydrogen gas that has flowed into port F1 of the hydrogen gas supply control valve 8B flows out from port F2. As a result, the hydrogen gas is sent to the hydrogen gas turbine 4.

[0087] In step S316, if the amount of hydrogen gas required in the hydrogen gas turbine 4 to generate the required amount of power is still insufficient, the process proceeds to step S317.

[0088] In step S317, the control unit 11 controls the liquid hydrogen supply control valve 7 so that the liquid hydrogen that has flowed into port A1 of the liquid hydrogen supply control valve 7 flows out from ports A3, A4, and A5. The liquid hydrogen that has flowed out from port A4 passes through pipe P15 and flows into port D1 of the liquid hydrogen supply control valve 7B.

[0089] In step S318, the control unit 11 controls the liquid hydrogen supply control valve 7B so that the liquid hydrogen that has flowed into port D1 of the liquid hydrogen supply control valve 7B flows out from ports D2 and D3. The liquid hydrogen that flows out from port D3 flows through pipe P5. The liquid hydrogen is converted into hydrogen gas by the hydrogen gasification mechanism 5 and flows into port F3 of the hydrogen gas supply control valve 8B.

[0090] In step S319, the control unit 11 controls the hydrogen gas supply control valve 8B so that the hydrogen gas that has flowed into port F3 of the hydrogen gas supply control valve 8B flows out from port F2. As a result, the hydrogen gas is sent to the hydrogen gas turbine 4.

[0091] In step S320, the control unit 11 turns on the hydrogen gasification mechanism 5. As a result, the liquid hydrogen flowing out from port A4 of the liquid hydrogen supply control valve 7 is converted into hydrogen gas and sent to the hydrogen gas turbine 4.

[0092] Modifications. In the above-described embodiment, in steps S107 and S209, the control unit 11 controls the hydrogen gas supply control valve 8 so that hydrogen gas that has flowed into port B1 of the hydrogen gas supply control valve 8 flows out from ports B2 and B3. However, this is not limited to this. The control unit 11 may also control the hydrogen gas supply control valve 8 so that hydrogen gas that has flowed into port B1 of the hydrogen gas supply control valve 8 flows out from port B2. In the above-described embodiment, in step S309, the control unit 11 controls the hydrogen gas supply control valve 8A so that hydrogen gas that has flowed into port E1 of the hydrogen gas supply control valve 8A flows out from ports E2 and E4. However, this is not limited to this. The control unit 11 may also control the hydrogen gas supply control valve 8A so that hydrogen gas that has flowed into port E1 of the hydrogen gas supply control valve 8A flows out from port E2.

[0093] 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.

[0094] 1 Liquid hydrogen storage unit, 2, 2A Superconducting generator, 3, 3A Magnetic refrigeration device, 4 Hydrogen gas turbine, 5 Hydrogen gasification mechanism, 6 Evaporated hydrogen amount detection unit, 7, 7A, 7B Liquid hydrogen supply control valve, 8, 8A, 8B Hydrogen gas supply control valve, 11 Control unit, 12 Drive unit, 13 Stator, 14 Superconducting rotor, 15 Magneto-caloric mechanism, 16 Magnetic field generator.

Claims

1. A superconducting power generation system comprising: a hydrogen gas turbine; a superconducting generator which is supplied with liquid hydrogen and driven by said hydrogen gas turbine; and a refrigeration device which vaporizes the liquid hydrogen supplied to said superconducting generator and cools the hydrogen gas flowing out of said superconducting generator to re-liquefy it.

2. The superconducting power generation system according to claim 1, further comprising a first valve configured to supply hydrogen gas flowing out from the superconducting generator to either one or both of the refrigeration device and the hydrogen gas turbine.

3. A superconducting power generation system as claimed in claim 1 or 2, further comprising: a liquid hydrogen storage unit for storing liquid hydrogen; and a second valve configured to be capable of supplying liquid hydrogen flowing out from the liquid hydrogen storage unit to either one or both of the superconducting generator and the hydrogen gas turbine, and configured to supply liquid hydrogen flowing out from the refrigeration device to either one or both of the superconducting generator and the liquid hydrogen storage unit.

4. A superconducting power generation system according to any one of claims 1 to 3, wherein the superconducting generator includes: a rotor formed of a superconductor; and a stator formed of a normal conductor.

5. A superconducting power generation system according to claim 4, wherein the rotor is cooled by the liquid hydrogen, and the stator is cooled by hydrogen gas vaporized from the liquid hydrogen.

6. A superconducting power generation system as claimed in any one of claims 1 to 5, wherein the refrigeration device includes: a magnetic field generating device formed from a superconductor; and a magnetocaloric mechanism that generates heat when an applied magnetic field increases and absorbs heat when the applied magnetic field decreases.

7. The superconducting power generation system according to claim 6, wherein said magnetic field generating device is cooled by said liquid hydrogen.

8. A superconducting power generation system as described in claim 7, further comprising a third valve configured to supply the liquid hydrogen flowing out from the second valve to either one or both of the superconducting generator and the magnetic field generating device.

9. A superconducting power generation system as described in claim 8, further comprising a control unit that switches between a hydrogen gas cooling operation using the endothermic reaction of the magnetocaloric mechanism and a liquid hydrogen heating operation using the exothermic reaction of the magnetocaloric mechanism by increasing or decreasing the magnetic field generated by the magnetic field generating device.

10. A superconducting power generation system as described in claim 9, wherein the second valve is configured to be able to supply liquid hydrogen flowing out of the liquid hydrogen storage unit to the magnetocaloric mechanism, and the control unit causes the hydrogen gas to flow into the magnetocaloric mechanism from the first valve during the cooling operation, and causes the liquid hydrogen to flow into the magnetocaloric mechanism from the second valve during the heating operation.

11. A superconducting power generation system as described in any one of claims 1 to 10, further comprising an evaporated hydrogen amount detection unit provided in a pipe for connecting the superconducting generator and the refrigeration device, and adjusting the flow rate from the first valve to the refrigeration device and the flow rate to the hydrogen gas turbine based on the amount of evaporated hydrogen detected by the evaporated hydrogen amount detection unit.

12. A superconducting power generation system according to any one of claims 1 to 11, further comprising a hydrogen gasification mechanism provided in a pipe connecting the second valve and the hydrogen gas turbine, for converting the liquid hydrogen flowing out of the second valve into hydrogen gas.

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