Device for cooling current lines of superconducting rotating machine

A cooling device for current lines of a superconducting rotating machine, which is capable of removing heat generated from the current lines of the superconducting rotating machine, thereby effectively preventing a superconducting coil from being deformed due to the heat generated from the current lines, is disclosed. The cooling device includes heat conduction members respectively mounted to outer surfaces of the current lines. Each heat conduction member is in contact with an inner peripheral surface of the stator such that the heat conduction member transfers, to the stator, heat generated from a corresponding one of the current lines. The heat conduction member further includes insulators each surrounding a corresponding one of the current lines between a corresponding one of the heat conduction members and a power slip ring arranged in the stator, to thermally insulate the heat generated from the corresponding current line.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device for cooling current lines of a superconducting rotating machine, and more particularly to a cooling device for current lines of a superconducting rotating machine, which is capable of removing heat generated from the current lines of the superconducting rotating machine, thereby effectively preventing a superconducting coil from being deformed due to the heat generated from the current lines.

2. Description of the Related Art

Generally, a superconducting rotating machine means a rotary driving device in which a superconducting coil is used as a field coil of a rotor, in place of a copper wire.

Referring toFIG. 3, a conventional superconducting rotating machine is illustrated. The conventional superconducting rotating machine includes a stator100having a sealed structure while including a stator coil101arranged in the stator100, and a rotor200arranged in the stator100while including a superconducting coil201arranged around an outer peripheral surface of the rotor200. The superconducting rotating machine also includes a support300mounted to an inner peripheral surface of the rotor200while extending through the stator100, a pair of current lines400each connected, at one end thereof, to the superconducting coil201while extending horizontally, a power slip ring500connected to the other end of each current line400, and mounted to an outer surface of the support300within the stator100, and a brush600extending through the stator100while being in contact with the power slip ring500.

An external electric power is supplied to the power slip ring500via the brush600. The electric power supplied to the power slip ring500is applied to the current lines400which will rotate together with the rotor200while being in contact with the power slip ring500. The electric power supplied to the current lines400is supplied to the superconducting coil201of the rotor200, thereby causing the rotor200to rotate within the stator100.

However, the above-mentioned conventional superconducting rotating machine has various problems.

For example, external heat may be transferred to the current lines via the brush and power slip ring. Furthermore, heat is generated at the current lines due to the resistance of the current lines. Such heat is transferred to the superconducting coil via the current lines, thereby causing the superconducting coil to be deformed.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above mentioned problems, and an object of the invention is to provide a cooling device for current lines of a superconducting rotating machine, which is capable of removing heat generated from the current lines of the superconducting rotating machine, thereby effectively preventing a superconducting coil from being deformed due to the heat generated from the current lines.

Another object of the invention is to provide a cooling device for current lines of a superconducting rotating machine, in which a thermoelectric element is used as a heat conduction member, not only to stably and effectively cool the current lines during supply of electric power through the current lines, but also to remove heat transferred from the current lines as the thermoelectric element comes into contact with air during rotation of a rotor.

In accordance with one aspect, the present invention provides, in a superconducting rotating machine including a stator having a sealed structure while including a stator coil arranged in the stator, a rotor arranged in the stator while including a superconducting coil arranged around an outer peripheral surface of the rotor, a support mounted to an inner peripheral surface of the rotor while extending through the stator, a pair of current lines each connected, at one end thereof, to the superconducting coil while extending horizontally, a power slip ring connected to the other end of each current line, and mounted to an outer surface of the support within the stator, and a brush extending through the stator while being in contact with the power slip ring, a cooling device for the current lines of the superconducting rotating machine, the cooling device comprising: heat conduction members respectively mounted to outer surfaces of the current lines, each heat conduction member being in contact with an inner peripheral surface of the stator such that the heat conduction member transfers, to the stator, heat generated from a corresponding one of the current lines; and insulators each surrounding a corresponding one of the current lines between a corresponding one of the heat conduction members and the power slip ring, to thermally insulate the heat generated from the corresponding current line.

Each heat conduction member may comprise a thermoelectric element including a cooling member mounted to the outer surface of the corresponding current line, and a heat radiating member provided at an upper surface of the cooling member; and a thermal link mounted to an upper surface of the heat radiating member while being in contact with the inner peripheral surface of the stator, to transfer heat from the heat radiating member to the stator, the thermal link being made of a metallic material.

The heat conduction member may further comprise high heat conduction layers respectively coated over upper and lower surfaces of the thermal link, using a material having a high thermal conductivity.

The material of each heat conduction layer may comprise thermal grease or indium.

The cooling device of the present invention can remove heat generated from the current lines of the superconducting rotating machine, thereby effectively preventing a superconducting coil from being deformed due to the heat generated from the current lines.

In the cooling device of the present invention, a thermoelectric element is used as the heat conduction member, so that it is possible not only to stably and effectively cool the current lines during supply of electric power through the current lines, but also to remove heat transferred from the current lines as the thermoelectric element comes into contact with air during rotation of the rotor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1is a schematic sectional view illustrating a cooling device for a superconducting rotating machine according to the present invention.

As shown inFIG. 1, the superconducting rotating machine includes a stator10having a sealed structure while including a stator coil11arranged in the stator10, and a rotor20arranged in the stator10while including a superconducting coil21arranged around an outer peripheral surface of the rotor20. The superconducting rotating machine also includes a support30mounted to an inner peripheral surface of the rotor20while extending through the stator10, a pair of current lines40each connected, at one end thereof, to the superconducting coil21while extending horizontally, a power slip ring50connected to the other end of each current line40, and mounted to an outer surface of the support30within the stator10, and a brush60extending through the stator10while being in contact with the power slip ring50.

An external electric power is supplied to the power slip ring50via the brush60. The electric power supplied to the power slip ring50is applied to the current lines40which will rotate together with the rotor20while being in contact with the power slip ring50. The electric power supplied to the current lines40is supplied to the superconducting coil21of the rotor20, thereby causing the rotor20to rotate within the stator10.

The cooling device for the superconducting rotating machine includes heat conduction members70respectively mounted to the outer surfaces of the current lines40, and insulators80each surrounding a corresponding one of the current lines40between a corresponding one of the heat conduction members70and the power slip ring50.

Each heat conduction member70is in contact with the inner peripheral surface of the stator10, to transfer, to the stator10, heat generated from the corresponding current line40, and thus to cool the current line40.

Each insulator80, which surrounds the corresponding line40, thermally insulates the heat generated from the current line40. By virtue of such thermal insulation, it is also possible to prevent heat transferred from the power slip ring50to the current line40from being transferred to air present within the stator10at the outer surface of the current line40.

Thus, the heat of each current line40is mainly transferred to the corresponding heat conduction member70, so that the current line40may be stably cooled.

FIG. 2is an enlarged sectional view illustrating an essential part of the cooling device according to the present invention.

As shown inFIG. 2, each heat conduction member70includes a thermoelectric element71. The thermoelectric element71includes a cooling member711mounted to the outer surface of the corresponding current line40, and a heat radiating member712provided at an upper surface of the cooling member711. The heat conduction member70also includes a thermal link72mounted to an upper surface of the heat radiating member712while being in contact with the inner peripheral surface of the stator10. The thermal link72is made of a metallic material.

The thermoelectric element71exhibits a Peltier effect when it receives electric power. In accordance with the Peltier effect, the thermoelectric element72cools the corresponding current line40through the cooling member711, while externally radiating heat from the current line40through the heat radiating member712. The supply of electric power to the thermoelectric element71may be achieved by directly connecting electric wires to the power slip ring50. Of course, other connection methods may be used.

The thermal link72may be made of a metallic material such as copper or silver, not only to perform a function to transfer heat radiated from the heat radiating member712to the stator10, but also to radiate heat as it is cooled by air present within the stator10while rotating together with the corresponding current line40.

The heat conduction member70further includes high heat conduction layers73respectively coated over upper and lower surfaces of the thermal link72, using a material having a high thermal conductivity. The high heat conduction layers73function to achieve effective heat conduction between the current line40and the thermoelectric element71, between the thermoelectric element71and the thermal link72, and between the thermal link72and the stator10.

The high heat conduction layers73, which have the above-described function, may be made of thermal grease or indium exhibiting excellent heat conductivity.