JP2007037341A - Cooling structure for superconducting equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure for a superconducting device having a simple structure with improved electrical reliability by using liquid nitrogen having electrical insulation for cooling the superconducting device.
A cooling container 11 for superconducting equipment that stores liquid nitrogen, a liquid hydrogen tank 13 that stores liquid hydrogen, a liquid hydrogen conduction path 12 that is connected to the liquid hydrogen tank 13, and a liquid hydrogen conduction path 12 are provided. And a heat exchanging means that is arranged in contact with the outer peripheral wall of the cooling container 11 and cools the liquid nitrogen to the cooling temperature for the superconducting material of the superconducting device 20 at the liquid hydrogen temperature.
[Selection] Figure 1

Description

  The present invention relates to a cooling structure for superconducting equipment, and more specifically, cools superconducting equipment such as a motor, a generator, a transformer, a superconducting power storage device (SMES), and a current limiter in a more stable state.

In recent years, in order to improve the exhaustion of fuel resources such as gasoline and the deterioration of the environment due to exhaust gas, the development of a ship that travels by driving a motor with electricity, a traveling automobile, and the like has been promoted. In particular, if a superconducting motor disclosed in Japanese Patent Laid-Open No. 6-6907 (Patent Document 1) is adopted, copper loss in the superconducting coil is eliminated and high efficiency is achieved, and the motor itself is reduced in size and output. Can do.
Superconductivity is also achieved using superconducting materials not only in motors but also in generators, transformers, superconducting power storage devices (SMES), current limiters, and the like.

In order to exhibit a superconducting characteristic of a superconducting material and to pass a large current, it is necessary to cool the superconducting material to an extremely low temperature. For example, liquid hydrogen, liquid nitrogen, or the like is used as a refrigerant. However, it is very difficult to measure the electrical insulation characteristics of liquid hydrogen, and it is not measured at present. If superconducting equipment is directly cooled with liquid hydrogen whose insulation characteristics are not clarified, electrical reliability may be impaired. There is.
Even when the superconducting device is accommodated and cooled in a container containing liquid nitrogen having insulating properties, there is a problem that a cooler or the like is required to cool the liquid nitrogen, and the apparatus becomes large and complicated.

JP-A-6-6907

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and by using liquid nitrogen having electrical insulating properties for cooling a superconducting device, the electrical reliability is improved, and the cooling structure for a superconducting device has a simple structure. It is an issue to provide.

In order to solve the above problems, the present invention firstly,
A cooling vessel for superconducting equipment that stores liquid nitrogen;
A liquid hydrogen tank for storing liquid hydrogen;
A liquid nitrogen channel that is connected to the inside of the cooling vessel;
A liquid hydrogen conducting path that is conducted to the liquid hydrogen tank;
Heat exchange means having a part of the liquid nitrogen channel and a part of the liquid hydrogen channel;
A cooling structure for a superconducting device is provided.

In addition, the present invention secondly,
A cooling vessel for superconducting equipment that stores liquid nitrogen;
A liquid hydrogen tank for storing liquid hydrogen;
A liquid hydrogen conducting path that is conducted to the liquid hydrogen tank;
The liquid hydrogen conduction path is disposed in contact with the outer peripheral wall of the cooling container, or heat exchange means in which a part of the liquid hydrogen conduction path is disposed in the cooling container;
A cooling structure for a superconducting device is provided.

According to the above configuration, since the superconducting material of the superconducting device is cooled by the liquid nitrogen having electrical insulation, it is possible to reliably prevent leakage and cool the superconducting material of the superconducting device in a stable state.
In addition, since the liquid nitrogen is cooled to the cooling temperature for the superconducting material of the superconducting equipment by the heat exchange means, a cooler for cooling the liquid nitrogen is not required and a simple cooling structure is provided. Can do.

  The cooling container is a cooling container that accommodates each superconducting material of the superconducting device and / or a cooling container that accommodates the entire superconducting device.

  According to the above configuration, when each superconducting material is accommodated in a cooling container and directly cooled, the superconducting device can be efficiently cooled without cooling the entire superconducting device, and the entire superconducting device can be cooled. If it is set as the structure which accommodates in and cools, a cooling structure can be made simple. Furthermore, if each superconducting material is accommodated in a cooling container for cooling, and the superconducting device itself is accommodated in the cooling container for cooling, the cooling efficiency of the superconducting material can be further increased.

The liquid hydrogen conducting path connected to the liquid hydrogen tank branches and then joins and is connected to a hydrogen engine or a fuel cell, and one branch flow path passes through the heat exchanging means, and a flow control valve is provided at the branch position. Intervene,
The flow path control valve is operated by a controller connected to a temperature sensor that detects the temperature of liquid nitrogen in the cooling container, and when the upper limit temperature threshold set by the controller is reached, the flow path to the heat exchange means side is opened. On the other hand, it is preferable that the flow path to the heat exchange means is closed when the lower limit temperature threshold is reached.

That is, when the liquid nitrogen in the cooling container is not cooled to a required temperature, the liquid nitrogen is cooled through the heat exchange means through the liquid hydrogen through the flow path through which the heat exchange means is interposed. It is supplied to fuel cells and reused as fuel. On the other hand, when the liquid nitrogen is cooled to a required temperature, the liquid hydrogen is passed through a flow path not including a heat exchanging means, and hydrogen vaporized in the middle of the liquid hydrogen conduction path is directly supplied to a fuel cell or the like. is doing.
According to the said structure, it can prevent that the liquid nitrogen in a cooling container is cooled too much more than necessary.

As described above, according to the present invention, since the superconducting material of the superconducting device is cooled by the liquid nitrogen having electrical insulation, the superconducting material of the superconducting device is reliably cooled in a stable state by preventing leakage. be able to.
In addition, since liquid nitrogen that cools the superconducting device is cooled by liquid hydrogen, a cooler or the like for cooling the liquid nitrogen is unnecessary, and a simple cooling structure can be achieved.

Embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a first embodiment of the present invention, and a superconducting equipment cooling structure 10 cools a superconducting motor 20 that serves as a driving source for traveling a ship or traveling an automobile.

The superconducting motor 20 is accommodated in a cooling container 11 that stores liquid nitrogen serving as a refrigerant for cooling the superconducting coil of the superconducting motor 20.
In the cooling structure 10 of the present embodiment, the liquid nitrogen in the cooling container 11 is cooled by the liquid hydrogen temperature, and one end of the liquid hydrogen conducting path 12 including a pipe through which the liquid hydrogen is circulated stores liquid hydrogen. The other end of the liquid hydrogen conducting path 12 is conducted to the fuel cell 14 while conducting to the liquid hydrogen tank 13 to be kept.

  The liquid hydrogen conduction path 12 is bifurcated in the middle, and a heat exchanger 15 is interposed in the middle of one branched flow path 12a, while a heat exchanger is interposed in the other branch flow path 12b. Not. These branched branch flow paths 12 a and 12 b are connected and joined downstream of the heat exchanger 15. In addition, it is good also as a structure which connects with the fuel cell 14 directly, without connecting the branch flow paths 12a and 12b.

  The heat exchanger 15 interposed in the branch flow path 12a is attached to the outer peripheral wall of the cooling vessel 11, and the liquid nitrogen in the cooling vessel 11 is cooled by liquid hydrogen flowing through the heat exchanger 15 (heat exchange means) ). Accordingly, the cooling container 11 is formed of a member having high thermal conductivity at the portion in contact with the heat exchanger 15, but the other portion is formed of a member having low thermal conductivity, and the temperature of the cooled liquid nitrogen is increased. The structure is difficult to rise.

A pump 16 is provided in the vicinity of the connecting portion between the liquid hydrogen conducting path 12 and the liquid hydrogen tank 13, and the liquid hydrogen in the liquid hydrogen tank 13 is introduced into the liquid hydrogen conducting path 12 by the pump 16.
Further, a flow path control valve 17 is provided at the upstream branch position of the branch flow paths 12a and 12b, and the flow path control valve 17 determines which of the branch flow paths 12a and 12b the liquid hydrogen is circulated through. It is configured to control. Specifically, a temperature sensor 18 for measuring the temperature of liquid nitrogen in the cooling container 11 and a controller 34 connected to the temperature sensor 18 are provided, and the temperature of liquid nitrogen measured by the temperature sensor 18 is provided. Is transmitted to the controller 34, and the flow path control valve 17 is operated by the controller 34. An upper limit temperature and a lower limit temperature are set in the controller 34. When the temperature of the liquid nitrogen transmitted from the temperature sensor 18 reaches a threshold value of the upper limit temperature (for example, 75 Kelvin), the flow to the heat exchanger 15 side is set. While the channel 12a is opened and the channel 12b is closed, the channel 12a is closed and the channel 12b is opened when the temperature of liquid nitrogen reaches a threshold value of a lower limit temperature (for example, 65 Kelvin).

  The liquid hydrogen flowing through the branch flow path 12 a is vaporized by cooling the liquid nitrogen, and the vaporized hydrogen is reused as fuel for the fuel cell 14. Further, the liquid hydrogen flowing through the branch flow path 12 b is also vaporized in the middle and reused as the fuel for the fuel cell 14. In the present embodiment, the electric power generated in the fuel cell 14 is used as a power source for the superconducting motor 20.

  The cooling container 11 covers the outer surface of the tank formed of the heat conductive material 30 with a heat insulating material 31, and the heat conductive material 30 is provided without providing the heat insulating material 31 only at the place where the cooling container 11 and the heat exchanger 15 are brought into contact with each other. Exposed outside. The cooling container 11 is provided with a shielding tube 33 that extends between the outlet 32 provided on the outer wall side and the superconducting motor 20. The rotating drive shaft 21 and the electric wire 22 that are drawn out from the superconducting motor 20 to the outside are provided. The cooling tube 11 is drawn out through the shielding tube 33. The inside of the shielding tube 33 is divided by a partition wall (not shown) so that the rotary drive shaft 21 and the electric wire 22 do not contact each other.

  The superconducting motor 20 is a motor having a radial gap structure, and an armature coil 24 made of a superconducting material is installed at an equal interval of 120 ° in the circumferential direction on the inner peripheral surface of a cylindrical stator 23 serving as a housing. Yes. An electric wire 22 connected to the armature coil 24 is branched into three branch wires 22a at a branch portion 25 fixed to the outer surface of the stator 23, and the power source of the fuel cell 14 and the like is connected via the electric wire 22. The three-phase alternating current is supplied to the armature coil 24. The armature coil may be formed of a normal conductive material.

A field coil 26 made of a superconducting material is fixed to the rotary drive shaft 21 that penetrates the stator 23, and one end side of the rotary drive shaft 21 extends through the bearing 27 to the drive transmission means 19.
As the superconducting material, a bismuth-based or yttrium-based superconducting material is used.

  The superconducting motor 20 operates in such a manner that a three-phase alternating current is supplied from the power source of the fuel cell 14 or the like to the armature coils 24, so that a rotating magnetic field is generated in the stator 23 due to a phase shift of power feeding to each armature coil 24. Under the influence of this rotating magnetic field, an eddy current is induced in the field coil 26 to generate a rotational force, and the rotary drive shaft 21 rotates.

According to the above configuration, since the superconducting motor 20 is cooled by liquid nitrogen having electrical insulation properties, the armature coil 24 and the field coil made of the superconducting material of the superconducting motor 20 are reliably prevented from being leaked and stabilized. 26 can be cooled.
Further, since liquid nitrogen for cooling the superconducting motor 20 is cooled by liquid hydrogen through the heat exchanger 15, a cooler for cooling the liquid nitrogen is not required, and a simple cooling structure can be obtained.
In this embodiment, the superconducting motor is cooled as a superconducting device, but the cooling structure of this embodiment is also applied to superconducting devices such as a generator, a transformer, a superconducting power storage device (SMES), and a current limiter. can do.
Further, the supply destination of the vaporized liquid hydrogen is not limited to the fuel cell, but may be other hydrogen using equipment such as a hydrogen engine.

FIG. 3 shows a second embodiment of the present invention.
In this embodiment, the heat exchange means for cooling the liquid nitrogen at the liquid hydrogen temperature, the liquid hydrogen conduction path 12 ′ passes through the through hole 11 a ′ of the cooling container 11 ′, and the heat exchanger 15 is placed in the cooling container 11 ′. 'Is arranged. The outer peripheral surface of the liquid hydrogen conducting path 12 ′ and the inner peripheral surface of the through hole 11a ′ of the cooling container 11 ′ are brought into close contact with each other so that liquid nitrogen in the cooling container 11 ′ does not leak. A rubber plug or the like may be interposed between the outer peripheral surface of the liquid hydrogen conducting path 12 ′ and the inner peripheral surface of the through hole 11a ′ of the cooling container 11 ′.

According to the said structure, since liquid nitrogen in cooling container 11 'is directly in contact with heat exchanger 15', liquid nitrogen can be cooled efficiently.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 4 shows a third embodiment of the present invention.
In the superconducting device cooling structure 40 of the present embodiment, the liquid nitrogen in the cooling container 41 is not directly cooled by liquid hydrogen, but a liquid nitrogen circulation path 42 for circulating liquid nitrogen that is conducted to the cooling container 41 is provided. The liquid nitrogen is cooled on the liquid nitrogen channel 42.

  A heat exchanger 43 is provided at a required location of the liquid nitrogen conduction path 42, and the heat exchanger 43 is disposed in the regenerator 44 close to the heat exchanger 15 provided in the liquid hydrogen conduction path 12 (heat Exchange means). The liquid nitrogen cooled to the required temperature by liquid hydrogen in the cold storage tank 44 is again introduced into the cooling container 41, and the superconducting material of the superconducting motor 20 is cooled by the liquid nitrogen.

According to the above configuration, the liquid nitrogen in the cooling container 41 is circulated in the liquid nitrogen conducting path 42, and the liquid nitrogen is cooled in the middle of the circulation. Therefore, the entire liquid nitrogen in the cooling container 41 is efficiently cooled. be able to.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 5 shows a fourth embodiment of the present invention.
In the cooling structure 50 of the superconducting device of this embodiment, the superconducting motor 51 is not housed in the cooling container to cool the entire superconducting motor 51, but each superconducting coil of the superconducting motor 51 is individually housed in the cooling container. It is cooling.

  The superconducting motor 60 cooled by the cooling structure 50 of the present embodiment is an inductor type motor having an axial gap structure, and includes a field side stator 61, a rotor 62, an armature side stator 63, a rotor 64, and a field magnet. The side stator 65 passes through the rotary shaft 66 in the order, and the field side stators 61 and 65 and the armature side stator 63 are fixed to the installation surface G and a gap is formed between the rotary shaft 66 and the rotors 62 and 64. Is externally fixed to the rotary shaft 66.

The field-side stators 61 and 65 and the armature-side stator 63 are respectively provided with cooling containers 67 and 68 having heat insulating properties that contain superconducting coils, and liquid nitrogen that is conducted to the cooling containers 67 and 68, respectively. A circulating liquid nitrogen channel 51 is provided. All the liquid nitrogen conducting paths 51 are joined, and a heat exchanger 52 is provided on the joining side, and heat exchange of the liquid hydrogen conducting path 55 in which the heat exchanger 52 is conducted to the liquid hydrogen tank 54 in the cold storage tank 53. It is set as the structure (heat exchange means) arrange | positioned close to the container 56. Therefore, the liquid nitrogen conducted through the liquid nitrogen conducting path 51 is cooled to a required temperature by the liquid hydrogen in the cold storage tank 53. Further, the hydrogen vaporized by heat exchange with liquid nitrogen is supplied to the fuel cell 57 connected to the liquid hydrogen conducting path 55 and reused.
In this embodiment, a pump, a temperature sensor, a controller, and a flow path control valve are provided. However, the illustration and description are omitted because they are the same as those in the first embodiment.

Next, the configuration of the superconducting motor 60 will be described.
The left and right symmetrical field side stators 61 and 65 are made of a yoke 69 made of a magnetic material fixed to the installation surface G, a cooling container 67 embedded in the yoke 69, and a superconducting material housed in the cooling container 67. And a field coil 70.
The yoke 69 includes a loose fitting hole 69b that is formed in the center so as to be larger than the outer diameter of the rotary shaft 66, and a groove 69a that is recessed in an annular shape around the loose fitting hole 69b. The cooling container 67 accommodates the field coil 70 in a state where liquid nitrogen is circulated, and the cooling container 67 is embedded in the groove 69a.

The symmetric rotors 62 and 64 are made of a non-magnetic material in a disk shape, and a pair of S pole inductions embedded in a point-symmetrical position with the mounting hole 71a as a center and a support portion 71 having a mounting hole 71a of the rotating shaft. And a pair of N-pole inductors 73 embedded in a position rotated by 90 ° from the S-pole inductor 72.
The S-pole inductor 72 and the N-pole inductor 73 have fan-shaped end faces facing the armature-side stator 63 arranged at equal intervals on concentric circles and have the same area.

The other end surface of the S-pole inductor 72 has a circular arc shape so as to be opposed to the S-pole generation position of the field coil 70.
The other end surface of the N-pole inductor 73 has an arc shape that is disposed so as to face the N-pole generation position of the field coil 70.

The armature side stator 63 includes a support portion 74 made of a nonmagnetic material fixed to the installation surface G, a cooling container 68 embedded in the support portion 74, and an armature made of a superconducting material housed in the cooling container 68. And a coil 75.
The support portion 74 includes a loose fitting hole 74b drilled at the center larger than the outer diameter of the rotating shaft 66, and four mounting holes 74a drilled at equal intervals in the circumferential direction around the loose fitting hole 74b. ing. The cooling container 68 accommodates the armature coil 75 in a state where liquid nitrogen is circulated, and a flux collector 76 made of a magnetic material is disposed in a hollow portion of the armature coil 75. Four cooling containers 68 containing the armature coils 75 are embedded in the mounting holes 74a.

  A power feeding device (not shown) is connected to the field coil 70 and the armature coil 75 via wiring, and a direct current is supplied to the field coil 70 and a three-phase alternating current is supplied to the armature coil 75. ing.

Next, the operation principle of the superconducting motor 60 will be described.
When a direct current is fed to the field coil 70 on the right side in FIG. 1, an S pole is generated on the outer peripheral side and an N pole is generated on the inner peripheral side. The magnetic flux on the S pole side is introduced into the S pole inductor 72, the S pole magnetic flux appears on one end face, the magnetic flux on the N pole side is introduced into the N pole inductor 73, and the N pole magnetic flux appears on one end face. .
When a direct current is supplied to the left field coil 70 in FIG. 1 according to the same principle, an N pole always appears on one end face of the N pole inductor 73 of the rotor 62, and an end face of the S pole inductor 72 appears. The S pole always appears.

  When a three-phase alternating current is fed to the armature coil 75 from this state, a rotating magnetic field is generated around the axis of the armature-side stator 63 due to a feeding phase shift between the three phases, and the rotors 62 and 64 are affected by the rotating magnetic field. A rotational force around the axis is generated in the N-pole inductor 73 and the S-pole inductor 72, the rotors 62 and 64 are rotated, and the rotary shaft 66 is rotationally driven.

According to the said structure, since each field coil 70 and the armature coil 75 are accommodated in the cooling containers 67 and 68, respectively, and are cooled, the field coil 70 and the armature coil 75 can be cooled efficiently, respectively. .
Further, since the field side stators 61 and 65 to which the field coil 70 is attached and the armature side stator 63 to which the armature coil 75 is attached do not rotate, the field coils 70 and the armature coil 75 are connected to each other. The cooling structure can be simplified even if the cooling containers 67 and 68 are respectively housed and cooled.

FIG. 6 shows a fifth embodiment of the present invention.
In the superconducting device cooling structure 80 of the present embodiment, the superconducting motor 60 itself of the fourth embodiment is also housed in a large cooling container 81 that stores liquid nitrogen. The cooling vessel 81 is also provided with a liquid nitrogen conduction path 82 for circulating liquid nitrogen, and the heat exchanger 83 provided in the liquid nitrogen conduction path 82 is disposed close to the heat exchanger 56 of the liquid hydrogen conduction path 55 in the cold storage tank 53. The configuration (heat exchange means) is used. That is, in this embodiment, the liquid nitrogen that is conducted to the two liquid nitrogen conducting paths 51 and 82 is cooled by the liquid hydrogen temperature.

According to the above configuration, each field coil 70 and armature coil 75 are housed in the cooling containers 67 and 68 for cooling, and the superconducting motor 60 itself is housed in the cooling container 81 for cooling. The cooling efficiency of the coil 70 and the armature coil 75 can be further increased.
In addition, since another structure and an effect are the same as that of 4th Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The cooling structure for a superconducting device according to the present invention is suitably used for cooling a superconducting device such as a motor, a generator, a transformer, a superconducting power storage device (SMES), and a current limiting device.

It is drawing which shows the cooling structure of the superconducting motor of 1st Embodiment of this invention. It is a principal part enlarged view of a cooling structure. It is a principal part enlarged view of the cooling structure of 2nd Embodiment. It is drawing which shows the cooling structure of the superconducting motor of 3rd Embodiment. (A) is drawing which shows the cooling structure of the superconducting motor of 4th Embodiment, (B) is sectional drawing in the position which rotated the superconducting motor 90 degrees. It is drawing which shows the cooling structure of the superconducting motor of 5th Embodiment.

Explanation of symbols

10, 40, 50, 80 Superconducting motor (superconducting equipment) cooling structure 11, 41, 67, 68, 81 Cooling vessel 12, 55 Liquid hydrogen conducting path 13, 54 Liquid hydrogen tank 14, 57 Fuel cells 15, 52, 56 83 Heat exchanger 16 Pump 17 Flow path control valve 18 Temperature sensor 20, 60 Superconducting motor 24, 75 Armature coil 26, 70 Field coil

Claims (5)

A cooling vessel for superconducting equipment that stores liquid nitrogen;
A liquid hydrogen tank for storing liquid hydrogen;
A liquid nitrogen channel that is connected to the inside of the cooling vessel;
A liquid hydrogen conducting path that is conducted to the liquid hydrogen tank;
Heat exchange means having a part of the liquid nitrogen channel and a part of the liquid hydrogen channel;
A cooling structure for superconducting equipment, comprising: A cooling vessel for superconducting equipment that stores liquid nitrogen;
A liquid hydrogen tank for storing liquid hydrogen;
A liquid hydrogen conducting path that is conducted to the liquid hydrogen tank;
The liquid hydrogen conduction path is disposed in contact with the outer peripheral wall of the cooling container, or heat exchange means in which a part of the liquid hydrogen conduction path is disposed in the cooling container;
A cooling structure for superconducting equipment, comprising:   The cooling structure for a superconducting device according to claim 1 or 2, wherein the heat exchange means cools liquid nitrogen with liquid hydrogen to a cooling temperature for a superconducting material of the superconducting device.   The cooling structure for a superconducting device according to any one of claims 1 to 3, wherein the cooling container is a cooling container for accommodating each superconducting material of the superconducting device and / or a cooling container for accommodating the entire superconducting device. . The liquid hydrogen conducting path connected to the liquid hydrogen tank branches and then joins and is connected to a hydrogen engine or a fuel cell, and one branch flow path passes through the heat exchanging means, and a flow control valve is provided at the branch position. Intervene,
The flow path control valve is operated by a controller connected to a temperature sensor that detects the temperature of liquid nitrogen in the cooling container, and when the upper limit temperature threshold set by the controller is reached, the flow path to the heat exchange means side is opened. The cooling structure for a superconducting device according to any one of claims 1 to 4, wherein the cooling structure is configured to close the flow path to the heat exchange means side when the lower limit temperature threshold is reached while opening.

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