JP4501449B2 - Cooling device for superconducting motor - Google Patents

Description

  The present invention relates to a cooling device for a superconducting motor, and more particularly, to improve a cooling mechanism of the superconducting motor to increase the heat exchange efficiency of the refrigerant and eliminate the need for a refrigerant circulation pipe.

  In recent years, in order to improve the exhaustion of fuel resources such as gasoline and the deterioration of the environment due to the exhaust gas of an internal combustion engine, the development of electric vehicles and hybrid vehicles that run by driving a motor with electricity has been promoted. When a normal conducting motor is used, there is a problem that it is difficult to increase the output because copper loss occurs due to electric resistance, resulting in low efficiency and limited current. Therefore, as disclosed in Japanese Patent Laid-Open No. 6-6907, if a superconducting motor is employed, copper loss in the superconducting coil is eliminated and high efficiency is achieved, and the motor itself can be reduced in size and output. it can.

In order to operate the superconducting motor, it is necessary to cool the superconducting coil to a superconducting temperature of extremely low temperature (for example, 77 Kelvin), and therefore the cooling means is very important.
In the cooling means, the refrigerant filling portion of the superconducting motor is circulated through the cooler and the piping, and the refrigerant vaporized by cooling the superconducting coil is liquefied by the cooler and filled in the refrigerant filling portion of the superconducting motor.

However, when the refrigerant is supplied through the pipe, there is a problem that the refrigerant cooled by the cooler is easily vaporized when flowing in the pipe, and the cooling efficiency becomes very poor. Also, if the refrigerant is in a liquid state, it is easy to vaporize when the superconducting coil of the superconducting motor is cooled, and the superconducting coil cannot be cooled for a long time and must be circulated through the cooler at all times. There is also a problem that the amount of power supply increases.
Furthermore, when the superconducting motor is driven and the cooler is also driven, it is necessary to supply power to both the superconducting motor and the cooler, and thus the generator needs to be enlarged.
JP-A-6-6907

  This invention is made | formed in view of the said problem, and makes it the subject to improve the cooling device of a superconducting motor, to raise the cooling efficiency of a superconducting coil, and to reduce the operating rate of a cooler.

In order to solve the above-mentioned problems, the present invention is a superconducting motor mounted on any one of mobile objects including an electric vehicle, a hybrid vehicle, a train, and an elevator,
A refrigerant filling portion is provided around or in the vicinity of a superconducting coil that is a stator and / or rotor of the superconducting motor, and a cooler is disposed close to the superconducting motor, and an external fixed power source is provided when the moving body is stopped. The cooling machine is operated by supplying electric power, and the cooling machine is cooled until the refrigerant in the refrigerant filling portion is solidified, and the superconducting coil is directly or indirectly cooled by the solidified solid refrigerant. A cooling device for a superconducting motor is provided.

With the above configuration, the refrigerant that cools the superconducting motor is cooled and solidified, and the superconducting coil of the superconducting motor is cooled with a solid refrigerant, so that the temperature of the refrigerant can be lowered than when it is liquid, and the superconducting characteristics of the superconducting motor Can be exhibited effectively and high output can be obtained.
In addition, since the solid refrigerant has a high heat capacity, the superconducting motor can be continuously cooled for a long time.
Furthermore, since the volume of the solid refrigerant hardly changes or decreases even when the refrigerant is liquefied, it is not necessary to increase the volume of the refrigerant filling portion, and the liquefied refrigerant is solidified while being filled in the refrigerant filling portion. And can be solidified.

A cold head of the cooler is directly inserted into the refrigerant filling part to solidify the liquefied refrigerant in the refrigerant filling part.
As described above, since the cooler is arranged in the vicinity of the superconducting motor device, the cold head of the cooler is directly inserted into the refrigerant charging portion of the superconducting motor, and the refrigerant liquefied by the cold head is solidified. As a matter of course, it is possible to eliminate the need for a refrigerant flow pipe that connects the refrigerant filling section and the cooler that have been provided in the past, and it is possible to eliminate the vaporization of the liquid refrigerant that has occurred between them, The heat exchange efficiency of the refrigerant can be utilized to the maximum, and the superconducting coil can be efficiently cooled.
Furthermore, since a circulation pipe for circulating the refrigerant is unnecessary, there is an advantage that the cooling mechanism does not become complicated and large.

Specifically, a superconducting coil is attached to the rotor of the superconducting motor, a hollow portion of the rotor is used as a refrigerant filling portion, and a cold head protruding from the cooler is inserted into the refrigerant filling portion to insert the superconducting coil. The refrigerant that is liquefied by cooling the coil is solidified.
In this case, since the hollow portion along the axis of the rotor is used as the refrigerant filling portion, the cold head can be inserted into the refrigerant filling portion without being rotated.

  Further, a superconducting coil is attached to the rotor of the superconducting motor and a normal conducting coil is attached to the stator, or a superconducting coil is attached to the rotor and the stator, and a space between the stator and the rotor is made of a high thermal conductive material. The outer peripheral space partitioned by the partition is used as a refrigerant filling portion, and a cold head protruding from the cooler is inserted into the refrigerant filling portion or a refrigerant filling pipe provided in communication with the refrigerant filling portion. The refrigerant that is liquefied by cooling the superconducting coil may be solidified.

  Further, the superconducting motor is covered with a refrigerant jacket filled with a refrigerant, and a cold head protruding from the cooler is inserted into a refrigerant filling portion of the refrigerant jacket to solidify the refrigerant liquefied by cooling of the superconducting coil. It is good.

  A Peltier element may be attached to the refrigerant jacket, and Peltier cooling may be used as an auxiliary cooling means to suppress liquefaction of the refrigerant.

The refrigerant is preferably configured to be solidified by operating the cooler when all of the refrigerant is liquefied.
That is, even in a liquefied state, any refrigerant that can cool the superconducting coil to the superconducting temperature can be used for cooling. Therefore, it is not necessary to operate the cooler, and the power consumption of the cooler can be reduced.

  From the above viewpoint, nitrogen, hydrogen, neon, argon, natural gas, ammonia, helium, or the like can be used as the refrigerant, and a refrigerant having a saturated vapor temperature of 15K to 100K under atmospheric pressure is preferably used.

  Specifically, a refrigerant temperature detection sensor is disposed in the refrigerant filling portion, and includes a determination unit that determines whether or not the refrigerant is liquefied based on a detection temperature from the sensor, and the refrigerant is liquid by the determination unit. When it is determined that the cooling machine is operated, the refrigerant is solidified.

In the present invention, as described above, the superconducting motor is a shall be mounted an automobile, a mobile body including a train or the like. If the superconducting motor is used as a moving force, is operated by supplying power from an external fixed supply during stop of the movable body to the cooling apparatus has a configuration to fix said refrigerant.

  With the above configuration, when a moving body such as an electric vehicle or a hybrid vehicle is moving, the cooler is not operated, so that all the power of the on-vehicle generator and battery can be used for driving without reducing the driving output. In addition, the generator and battery can be reduced in size. In addition, when the cooling unit is operated by an external power source while the moving body is stopped to solidify the refrigerant, the amount of power supplied from the in-vehicle battery can be reduced.

  The superconducting wire forming the superconducting coil of the superconducting motor is, for example, a bismuth oxide / strontium / calcium / copper superconducting material, a yttrium oxide / barium / copper superconducting material, a mercury based superconducting material, or thallium based. A high-temperature superconducting material made of an oxide such as a superconducting material is used.

As is clear from the above description, according to the present invention, since the refrigerant for cooling the superconducting motor is solidified and the superconducting coil of the superconducting motor is cooled by the solid refrigerant, the temperature can be made lower than that of the liquid refrigerant, The superconducting characteristics of the superconducting motor can be further exhibited to obtain a high output.
In addition, since the solid refrigerant has a high heat capacity, the superconducting motor can be continuously cooled for a long time.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of a cooling device for a superconducting motor for driving a vehicle mounted on an electric vehicle. The electric vehicle is a fuel cell vehicle that generates electricity by reacting hydrogen and oxygen.
The vehicle on which the superconducting motor of the present invention is mounted is not limited to a fuel cell vehicle, and may be a hybrid vehicle, and can be applied to all moving objects such as trains and elevators driven by the superconducting motor.

  In the superconducting motor 10, the superconducting coil 13 is disposed on the stator 11, while the rotor 20 inside the stator 11 is configured such that the superconducting coil 15 is fixed to the rotation drive shaft 12. As the superconducting coils 13 and 15, bismuth-based, yttrium-based, and thallium-based oxide superconductors are used.

In an annular space between the rotor 20 and the stator 11, a partition wall 16 made of a high thermal conductivity material is provided, and an outer peripheral space partitioned by the partition wall 16 is used as a refrigerant filling portion 22. The refrigerant filling portion 22 is cooled by inserting a cold head 31 protruding from the cooler 30 into a through-hole 11a formed in the end face of the stator 11, contacting the liquid nitrogen sealed in the refrigerant filling portion 22, and cooling the liquid nitrogen. Is solidified into solid nitrogen S. Liquid nitrogen is sealed in the refrigerant filling unit 22 in advance, and the liquid nitrogen comes into contact with the cold head 31 to be cooled and solidified to be solid nitrogen S, while the liquefied nitrogen is supplied to the cooler 20. By operating, it is solidified again by contact with the cold head 31 to become solid nitrogen.
The temperature of the solid nitrogen S is 63K or less, which is a sufficiently low temperature as a coolant for the superconducting material.

  The superconducting coil 13 of the stator 11 is covered and directly cooled by the solid nitrogen S, while the rotor-side superconducting coil 15 is indirectly cooled by the solid nitrogen S via the partition wall 16. Since the partition wall 16 is formed using a high thermal conductive material such as copper, silver, diamond, and aluminum (such as aluminum nitride), the superconducting coil 15 on the rotor side is sufficiently cooled to the superconducting temperature.

  The cooler 30 is connected to a battery 33 mounted on the vehicle. Further, a temperature sensor 40 is attached to the inner surface of the stator 11 facing the refrigerant filling portion 22, and a discriminating means 41 that receives a detection signal from the temperature sensor 40 is provided. The circuit with the machine 30 is opened, the cooling machine 30 is operated, and the cold head 31 is switched to the cooling mode. That is, when the determination unit 41 determines that the temperature measured by the temperature sensor 40 is the temperature at which all the refrigerant has been liquefied, the cooler 30 is operated to cool and solidify the liquefied nitrogen to form solid nitrogen again. .

  The outer peripheral surface of the stator 11 is surrounded by a heat insulating material 17. Further, a cord 34 is connected to the cooler 30 to enable connection with a household power source 35. Therefore, when the vehicle is stopped at night, the household power supply 35 and the cooler 30 can be connected to supply power to the cooler 30 to solidify the liquefied nitrogen when the vehicle is stopped.

With this configuration, since the refrigerant that cools the superconducting coils 13 and 15 is solidified, the temperature can be lowered from the liquid state, and the superconducting coil can be sufficiently cooled to a superconducting temperature or lower. In addition, even if the refrigerant is heated and liquefied by cooling, if the refrigerant can cool the superconducting coil to the superconducting temperature, the cooling time by the refrigerant can be maintained for a long time.
In addition, the cold head 31 is directly inserted into the refrigerant filling portion 22 and the refrigerant filling portion 22 is left in a state in which the refrigerant is sealed, so that liquefaction and solidification are repeated. There is an advantage that the heat loss due to vaporization of the refrigerant that is not required and is generated when the piping is circulated does not occur.

  Further, since the temperature of the refrigerant is detected by the temperature sensor 40 and the cooling unit 30 is operated in a state where all of the refrigerant is liquefied by the discrimination means 41 to solidify the refrigerant, the cooling unit 30 is operated only when necessary. There is an advantage that the power supplied from the battery is not increased. Furthermore, when the cooler 30 is operated with a household power source when the vehicle is stopped at night, for example, the refrigerant is solidified, the amount of electric power necessary for the solidification of the refrigerant can be reduced from the on-board battery or generator.

  2 and 3 show a second embodiment, in which the superconducting motor 10 is surrounded by a cooling jacket 50 filled with liquid hydrogen serving as a refrigerant. The cooling jacket 50 is formed of a high thermal conductivity material, and includes a refrigerant filling portion 51 inside, and liquid hydrogen is sealed in the refrigerant filling portion 51 in advance. As in the first embodiment, the cold head 31 of the cooler 30 is directly inserted into the refrigerant filling portion 51 and brought into contact with the refrigerant to solidify liquid hydrogen into solid hydrogen S ′.

Further, a Peltier element 62 is attached to the outer peripheral surface of the cooling jacket 50 as an auxiliary cooling means to delay the liquefaction of the solid hydrogen S ′.
As shown in FIG. 3, the Peltier element 62 is adhered to the outer surface of the cooling jacket 50 with the heat absorbing surface 62a of the Peltier element 62 in contact therewith, thereby cooling the refrigerant. The Peltier element 62 has a configuration in which heat transfer elements 62c and 62d made of p-type and n-type semiconductors are arranged in parallel and connected in series to pass current, and ceramic plates 62e and 62f are attached to both sides. When the Peltier element 62 is energized, a heat absorbing surface 62a and a heat radiating surface 62b are generated by the Peltier effect, and the solidified refrigerant of the cooling jacket 50 that contacts the heat absorbing surface 62a is cooled, and liquefaction can be delayed.

  A refrigerant temperature detection sensor 40 is attached to the refrigerant charging portion 51 of the cooling jacket 50, and the sensor 40 is connected to the discriminating means 41 to control the operation of the cooler 30, and can be connected to a household power supply. This is the same as in the first embodiment.

  With this configuration, the entire superconducting motor 10 is cooled by the solid refrigerant in the cooling jacket 50, and any of the cases where the superconducting coil is provided only on both the stator 11 and the rotor 20 or on the rotor 20 side. In this case, the superconducting coil can be sufficiently cooled to the superconducting temperature. Since other operations are the same as those of the first embodiment, description thereof is omitted.

FIG. 4 shows a third embodiment. In the superconducting motor 10, a superconducting coil 15 ′ is attached to the outer peripheral surface of the rotational drive shaft 12 ′, the rotational drive shaft 12 ′ is a hollow shaft, and the hollow portion along the axis is a refrigerant. The filling portion 20a ′ is used. One end of the rotary drive shaft 12 ′ protrudes outside from the superconducting motor 10 and is connected to the drive transmission means, while the other end of the rotary drive shaft 12 ′ directly connects the cold head 31 of the cooler 30 to the refrigerant filling portion 20a ′. It is inserted to solidify liquid nitrogen into a solid refrigerant.
A normal conducting coil 60 is attached to the stator 11 ′ of the superconducting motor 10.

With the above-described configuration, a refrigerant filling portion is provided in the shaft core of the rotor to which the superconducting coil 15 ′ is attached, and the liquid nitrogen sealed in the refrigerant filling portion is cooled and solidified by the cold head 31. Therefore, the superconducting coil 15 ′ can be sufficiently cooled to the superconducting temperature.
Since other configurations and operations are the same as those in the first and second embodiments, the description thereof will be omitted.

  The superconducting motor device of the present invention is suitably used as a power source for moving bodies such as electric vehicles and hybrid vehicles. Further, in a device using a superconducting motor as well as a moving body, it is necessary to cool the superconducting material to the superconducting temperature, and therefore the cooling device of the present invention can be suitably used.

It is sectional drawing of 1st Embodiment of this invention. It is sectional drawing of 2nd Embodiment of this invention. It is the schematic of the Peltier device used for auxiliary | assistant cooling in 2nd Embodiment. It is sectional drawing of 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Superconducting motor 11 Stator 12 Rotation drive shafts 13 and 15 Superconducting coil 22 Refrigerant filling part 30 Cooling machine 31 Cold head 50 Cooling jacket 62 Peltier element

Claims (10)

A superconducting motor is installed in one of moving vehicles including electric cars, hybrid cars, trains, and elevators.
A refrigerant filling portion is provided around or in the vicinity of a superconducting coil that is a stator and / or rotor of the superconducting motor, and a cooler is disposed close to the superconducting motor, and an external fixed power source is provided when the moving body is stopped. The cooling machine is operated by supplying electric power, and the cooling machine is cooled until the refrigerant in the refrigerant filling portion is solidified, and the superconducting coil is directly or indirectly cooled by the solidified solid refrigerant. A cooling device for a superconducting motor.   The cooling device for a superconducting motor according to claim 1, wherein the cooling head is configured to solidify the refrigerant by directly inserting a cold head of the cooler into the refrigerant filling portion.   A superconducting coil is attached to the rotor of the superconducting motor, and a hollow portion of the rotor is used as a refrigerant filling portion, and a cold head protruding from the cooler is inserted into the refrigerant filling portion to liquefy the cooling of the superconducting coil. The cooling device for a superconducting motor according to claim 1, wherein the cooling refrigerant is solidified.   A superconducting coil is attached to the rotor of the superconducting motor and a normal conducting coil is attached to the stator, or a superconducting coil is attached to the rotor and the stator, and a partition made of a high thermal conductivity material in the space between the stator and the rotor. The outer peripheral space partitioned by the partition wall is used as a refrigerant filling portion, and a cold head protruding from the cooler is inserted into the refrigerant filling portion or a refrigerant filling pipe provided in communication with the refrigerant filling portion, and The cooling device for a superconducting motor according to claim 1 or 2, wherein the refrigerant that is liquefied by cooling the superconducting coil is solidified.   The superconducting motor is covered with a refrigerant jacket filled with a refrigerant, and a cold head protruding from the cooler is inserted into a refrigerant filling portion of the refrigerant jacket to solidify the refrigerant liquefied by cooling of the superconducting coil. The cooling device for a superconducting motor according to claim 1 or 2.   The cooling device for a superconducting motor according to claim 5, wherein a Peltier element is attached to the refrigerant jacket to suppress liquefaction of the refrigerant.   The cooling device for a superconducting motor according to any one of claims 1 to 6, wherein when the refrigerant is liquefied, the cooling device is operated to solidify the refrigerant.   When a refrigerant temperature detection sensor is disposed in the refrigerant filling portion and includes a determination unit that determines whether or not the refrigerant is liquefied from the detected temperature from the sensor, and when the determination unit determines that the refrigerant is liquid The cooling device for a superconducting motor according to any one of claims 1 to 6, wherein the cooling machine is operated to solidify the refrigerant. The superconductivity according to any one of claims 1 to 8 , wherein nitrogen, hydrogen, neon, argon, natural gas, ammonia or helium is used as the refrigerant, and the refrigerant is solidified to cool the superconducting coil. Motor cooling device. The superconducting device according to any one of claims 1 to 9, wherein the superconducting motor is mounted on an electric vehicle or a hybrid vehicle, and is configured to solidify the refrigerant by operating the cooler with a household power supply when the vehicle stops at night. Motor cooling device.

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