KR20100101869A - Cylindrical type superconducting power supply - Google Patents

Abstract

PURPOSE: A cylindrical superconductive power device is provided to efficiently control a current by generating a magnetic flux from an AC coil wound around a cylindrical iron core. CONSTITUTION: A permanent magnet core(110) generates a magnetic flux for compensating the movable magnetic flux of an AC coil(130). A superconductive thin film(116) surrounds the outer surface of a permanent magnet core. A superconductive thin film generates a pumping current by the movable magnetic flux of the AC coil. The permanent magnet coil and the superconductive thin film are arranged in an air gap inside a cylindrical iron core(120). A plurality of slots are formed on the inner surface of the cylindrical iron core. The AC coil is wound around the slot.

Description

Cylindrical Superconducting Power Supply {Cylindrical Type Superconducting Power Supply}

The present invention relates to a cylindrical superconducting power supply using a superconductor thin film (Nb, MgB2).

Superconducting power supplies are classified into rectifier type superconducting current compensators using superconducting switches and transformers, and magnetic flux pump superconducting current compensators that generate current through changes in the phase of the superconducting thin film by moving magnetic flux. .

Among them, the flux pump type superconducting current compensator uses a low temperature superconducting thin film (Nb) and a high temperature superconducting thin film (MgB2) to generate stable current.

In general, the superconductor is a material having a perfect conductor property, a fully diamagnetic property, and a Josephson phenomenon. Recently, the superconductor can be cooled sufficiently below a critical temperature, and various devices using the superconductor have been actively developed.

In particular, the superconducting power supply is based on the law of magnetic flux preservation, that is, the theory that the magnetic flux that bridges the complete superconducting circuit is constant, and has a configuration that supplies the current generated in the superconducting thin film that bridges the magnetic flux to the load. Research is being done.

FIG. 1 is a diagram illustrating a basic principle of a rotating superconducting power supply device used in a flux pump type superconducting current compensator, and the basic operation principle of the superconducting power supply device will be described with FIG. 1.

After connecting the niobium (Nb) plate 10, which is a low-temperature superconductor, with a superconducting magnet 13 to form a closed loop, the closed loop is superconducting in the current mode. There is no energy loss.

At this time, the magnetic flux of the permanent magnet 12 is applied directly to the niobium plate 10 so that the magnetic flux penetrates. The area in which the magnetic flux penetrates is called a normal spot 11, except for the normal spot 11 region, while maintaining the superconducting state, while the normal spot 11 region maintains the superconducting state.

When the region of the normal spot 11 is moved in the superconducting closed circuit including the niobium plate (Nb foil), which is a low temperature superconductor, that is, when it is moved in the order of (a)-> (b)-> (c) of FIG. In accordance with the law of Lenz's Law, a current is applied to the niobium plate in a direction that interferes with the applied magnetic field. This current is continuously induced by the repetitive movement of the normal spot 11 region. At this time, the induced current is called a pumping current and the pumping current is charged to the superconducting magnet 13 through a closed circuit.

On the other hand, the superconducting thin film of niobium is less than the case of the (4.2K), the critical magnetic field value at the liquid haelryum μ ₀ H _c1 (0.16T) or higher μ ₀ H _c2 (0.3T) is a mix (mixed state), moving the magnetic flux (the time-varying magnetic flux) When applied, there must be a phase change (superconducting state-> mixed state) to induce pumping current.

In order to move the normal spot in the superconducting niobium thin film 10, the permanent magnet is rotated by the rotation of the rotating body so that the time-varying magnetic flux is applied to the niobium thin film so that the normal spot is moved. As shown in FIG. 2, in order to be charged to the superconducting magnet 13 through a closed circuit, the permanent magnet 12 must be rotated on the niobium thin film 10 by a separate rotor 14, where the niobium thin film ( The movement of the normal spot 11 is made in 10 and may generate a pumping current.

3 illustrates another embodiment of a rotary superconducting power supply device for moving a normal spot. The niobium thin film 10, which is a low-temperature superconductor, is formed in a cylindrical cylinder to be connected to a superconducting magnet 13 to form a closed loop. In addition, the permanent magnet 12 is rotated by the rotating body 14, and a magnetic flux is applied to the cylindrical cylindrical niobium thin film 10 to generate a pumping current due to the movement of the normal spot.

As shown in FIG. 2 and FIG. 3, the rotation type superconducting power supply device is inconvenient to require a separate rotor 14 for rotating the permanent magnet 12 in order to achieve normal spot movement in the niobium thin film. There is this. Such a rotating body not only complicates the configuration of the superconducting power supply device but also causes a problem of increasing manufacturing costs.

In addition, when generating a normal spot using a niobium thin film which is a low temperature superconductor as in the conventional rotary superconducting power supply, there is a problem in that the generation efficiency of the pumping current is lowered.

The present invention relates to a cylindrical superconducting flux pump power supply using a transition phenomenon of a superconducting thin film by applying a moving magnetic flux to the superconducting thin film by applying a three-phase synchronous generator.

The present invention is provided with a permanent magnet in the rotor portion of the core-type synchronous motor, so that the moving flux by the AC coil is biased in the '+' direction to generate a homopolar traveling magnetic flux (homopolar traveling magnetic flux) It solved the problem of efficiency deterioration due to the rotation system of the system, and wrapped around the outer surface of the permanent magnet to prevent magnetic saturation. A superconductor thin film for generating a pumping current by the heterogeneous magnetic flux, the permanent magnet, the iron core and the superconductor thin film are installed in an air gap, and a cylindrical iron core having a plurality of slots formed along an inner circumferential surface thereof; It includes a three-phase coil wound around the slot.

Each AC coil features two slots in pairs.

Each AC coil is positioned opposite to each other on the inner circumferential surface of the cylindrical iron core and is wound by pairing two opposite slots.

Each AC coil is positioned opposite to each other and wound in pairs of two opposite slots, and then wound into a pair of two slots opposite to each other next to each other.

The AC coil includes a first AC coil, a second AC coil, and a third AC coil to which a three-phase AC current is applied.

When the three-phase AC current has a phase sequence of A phase-> B phase-> C phase, A phase is applied to the first AC coil, C phase is applied to the second AC coil, and B phase is applied to the third AC coil.

The present invention proposes a cylindrical flux pump power supply using a cylindrical superconducting thin film and a permanent magnet, thereby improving the manufacturability and efficiency of the superconducting power supply. In addition, the present invention has the effect of efficient current control by generating a moving magnetic flux using an AC coil wound around a cylindrical iron core.

Hereinafter, a detailed description of embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the reference numerals to the components of the drawings it should be noted that the same reference numerals as possible even if displayed on different drawings.

4 is a view illustrating a state in which a cylindrical magnetic flux pump power supply according to an embodiment of the present invention is connected to a load magnet to charge a load magnet, and FIG. 5 is a cross-sectional view of the cylindrical magnetic flux pump power supply according to an embodiment of the present invention. Is a picture showing.

The pumping current generated in the power supply device implemented by the cylindrical type magnetic flux pump of the present invention is provided to a load magnet made of a superconductor to charge a constant current in the load magnet.

The cylindrical magnetic flux pump power supply 100 generates a moving magnetic flux without the rotation of the superconducting thin film Nb or MgB ₂ to generate a pumping current by moving a normal spot on the superconducting thin film 116. Therefore, it does not need a separate rotor for rotating the superconductor thin film.

In order to generate the pumping current by generating the moving magnetic flux without rotating the superconductor thin film 116, the cylindrical magnetic flux pump power supply 100 wraps the outer surface of the permanent magnet core 110, the permanent magnet core to pump the current by the moving magnetic flux The superconducting thin film 116, the permanent magnet core 110, and the superconducting thin film 116 that are generated are placed in an air gap, and a cylindrical iron core 120 formed by protruding a slot into the inside is wound around the slot. It is provided with an AC coil 130 to generate.

The cylindrical iron core 120 is made of an iron core material and has a plurality of slots 122 having a predetermined interval on the inner circumferential surface thereof while having an air gap therein.

A plurality of slots 122 having a gap are formed inward along the inner circumferential surface of the cylindrical iron core 120.

The AC coil 130 is wound around the slot 122, and the AC coil is wound by pairing two slots. The AC coil refers to a coil to which an AC current is applied, and generates a moving magnetic flux by receiving the AC current.

For reference, in the case of a known cylindrical rotary motor, as shown in FIG. 6, the AC coils are wound in a direction facing each other inside the cylinder, and then a three-phase AC current flows to generate magnetic flux. In other words,

i _{aa '} (t) = I _M sinωt [A]

i _{bb '} (t) = I _M sin (ωt-120 °) [A]

i _{cc '} (t) = I _M sin (ωt-240 °) [A]

If a three-phase AC current of different phase as described above is applied to each AC coil,

H _{aa '} (t) = H _M sinωt∠0 ° [Aturn / m]

A magnetic field having a direction of is formed.

The present invention utilizes such a magnetic field formation characteristic to place a plurality of slots in a cylindrical interior, thereby generating a moving magnetic flux by flowing three-phase AC current in the direction facing each other on the circumferential surface of the cylinder.

In the following description, preferably, for example, 18 slots formed on the outer circumferential surface inside the cylindrical iron core will be described. However, the number of slots may vary according to the generation form of the moving magnetic flux.

The AC coil includes a first AC coil, a second AC coil, and a third AC coil to which a three-phase AC current is applied.

Each of these AC coils are wound separately in the slots. In FIG. 4 and FIG. 5, the AC coils are wound around the slots in a circular form only in a symbolic representation. Explain.

FIG. 7 is a diagram illustrating an imaginary view when a slot formed on a circumferential surface of a cylindrical iron core is unfolded on a plane to facilitate understanding of a winding structure of an AC coil wound around a slot.

In addition, in FIG. 7, for convenience of explanation, an example of winding one AC coil is wound. However, each winding of the AC coil wound in the slot may have various winding numbers according to the strength of the moving magnetic flux. The number of turns depends on the strength of the designed magnetic flux, taking into account the threshold value at which the transition from the superconducting state to the mixed state occurs.

Each AC coil is wound in pairs of two slots, where two pairs of slots refer to two slots located opposite each other on the inner circumferential surface of the cylindrical iron core.

For example, slots a1, a2, a3, b1, b2, b3, c1, c2, c3, a'1, a'2, a'3, b'1, b'2, b'3, c'1, Supposed to 12 slots of c'2, c'3, a1-a'1, a2-a'2, a3-a'3, b1 located opposite each other on the inner circumferential surface of the cylindrical iron core. -b'1, b2-b'2, b3-b'3, c1-c'1, c2-c'2 and c3-c'3 form a pair of slots, and the AC coil is It is a cold.

At this time, each AC coil is wound in turn to a pair of adjacent slots, that is, each AC coil is wound on a pair of two slots facing each other located opposite to each other, and then wound again to the next pair of slots in turn. Has a structure.

For example, the first AC coil is first wound on a1-a'1 opposite each other on the inner circumferential surface, then again on the next pair of slots a2-a'2, and finally a3-a'3. Is wound in a pair of slots.

Similarly, the second AC coil is first wound on c'1-c1 opposite each other on the inner circumferential surface, then again on the next pair of slots c'2-c2, and finally on slots c'3-c3. Coiled in pairs.

Also in the case of the third AC coil, the third AC coil is first wound on b1-b'1 opposite to each other on the inner circumferential surface, and then again on the next pair of slots b2-b'2, and finally It is wound around a pair of slots of b3-b'3.

As described above, when the first, second, and third AC coils are sequentially wound in the slots, three-phase AC currents are respectively applied to the AC coils to generate the magnetic flux.

In this case, the phase sequence of the three-phase AC current is applied in order of the first AC coil, the third AC coil, and the second AC coil. That is, when the three-phase AC current has a phase sequence of A phase-> B phase-> C phase, as shown in FIG. 7, the A phase is the first AC coil, the C phase is the second AC coil, and the third AC coil. Phase B is applied to.

As a result, as three-phase AC currents having different phases are applied to the respective AC coils, moving magnetic fluxes are generated to generate pumping currents due to the movement of normal spots in the superconducting thin film.

Referring to FIG. 8, which shows an enlarged region of the moving magnetic flux penetrating the superconducting thin film, the moving magnetic flux generated in the air gap inside the three-phase AC coil is transmitted to the superconducting thin film to generate a normal spot region. The normal spot area is moved by the moving flux.

Due to the moving flux, the phase transition (superconducting state-> mixed state) of the superconducting thin film is generated continuously to generate the pumping current. As described above, the pumping current generated in the superconducting thin film is moved to the load magnet constituting the closed circuit, thereby charging the load magnet.

On the other hand, as shown in FIG. 9, when looking at the distribution map of the magnetic flux generated in the three-phase AC coil wound in three-phase, the magnetic flux density of the moving magnetic flux generated in the three-phase AC coil is generated by two poles ('0') It can be seen that it is a sinusoidal shape in the '+' and '-' directions.

Since the superconductor thin film (Nb or MgB ₂ thin film) has a phase transition (superconducting state-> mixed state) phenomenon at the critical point (μ ₀ H _c1 ), it is necessary to raise the moving magnetic flux upwards around the critical point as a whole.

For this purpose, the magnetic flux generated from the permanent magnet in the permanent magnet increases the distribution of the moving magnetic flux of the AC coil in the direction of '+' value, that is, the magnetic flux generated by the permanent magnet is caused by the three-phase AC current. It serves to float the generated sinusoids in a bias, that is, the '+' direction.

This permanent magnet core will be described.

The permanent magnet 110 is a material of the iron core 114 having a pillar-shaped permanent magnet 112 as a core, the magnetic flux of the direct current form in the permanent magnet.

The magnetic flux generated in the permanent magnet is supplemented so that the moving magnetic flux generated by the AC coil has a '+' value as shown in FIG. 9, that is, the magnetic flux generated by the permanent magnet is generated by the AC current of the AC coil. It moves the moving flux so that it has a '+' value.

Referring to the distribution map of the magnetic flux generated in the three-phase AC coil to which the three-phase AC current shown in FIG. 9 is applied, the magnetic flux density of the magnetic flux generated in the three-phase AC coil is generated by two poles. It can be seen that it appears up and down repeatedly in the '+' and '-' directions.

Since the superconductor thin film 116 has a phase transition (superconducting state-> mixed state) phenomenon at the critical point μ ₀ H _c1 , it is necessary to raise the moving magnetic flux to the upper side around the critical point as a whole. For this purpose, the magnetic flux generated by the permanent magnet increases the distribution of the moving magnetic flux of the AC coil in the direction of '+' value.

The superconductor thin film 116 surrounds the outer surface of the permanent magnet core and generates a pumping current by the moving magnetic flux generated by the AC coil 130.

As described above, the superconductor thin film 116 is located under the AC coil 130 and generates a pumping current by the moving magnetic flux. The superconductor may be implemented as an object of a material having superconductivity, but in the present invention, the superconductor may be implemented through niobium, which is a low temperature superconducting wire, and a MgB ₂ thin film having a high critical current density (J _c ) as a high temperature superconducting wire.

In particular, MgB ₂ , a recently developed high temperature superconducting wire, has a large critical current density (Jc), but in the case of film, phase transition (superconducting state-> mixed state) occurs even when a small magnetic flux starts to penetrate. There is this.

In addition, the MgB ₂ material has a superconductivity at 39K (minus 234 degrees C) as a superconductor, and thus has a higher critical temperature than other superconductors. It is easily available and has the advantage of being processed into wires or thin films.

MgB ₂ wire has a large critical current density, so a large magnetic field must be applied to change the state from superconducting state to mixed state, but in case of MgB ₂ thin film, the critical current density penetrates and is rapidly reduced by magnetic field. It is possible to apply it and there is no application case of superconducting power supply using MgB ₂ thin film.

On the other hand, as shown in Figure 4, the load magnet 200 is charged by the pumping current generated in the cylindrical magnetic flux pump power supply, a rotating superconducting power supply used in the conventional flux pump type superconducting current compensation device (Fig. 2, FIG. 3), since the pumping current is controlled at the speed of the rotation system (motor) to control the pumping current for charging, fine current control is limited.

When the cylindrical flux pump power supply of the present invention is applied to a superconducting current compensation circuit, as shown in FIG. 10, an additional magnet 300 is placed at the output terminal of the cylindrical flux pump power supply 100 so as to be continuous to the load magnet 200. Phosphorous charge current control can be achieved.

The additional magnet 300 provided at the output end of the cylindrical magnetic flux pump power supply 100 has the same inductance as the load magnet 200 charged by the pumping current output of the cylindrical magnetic flux pump power supply.

If an additional magnet 300 having the same inductance value as the inductance of the load magnet 200 is provided at the output terminal, the inductance value of the entire closed loop may be increased to reduce the current attenuation of the load magnet 200.

In addition, since the charging current generated through the cylindrical magnetic flux pump power supply 100 is also compensated through the additional magnet, the current gradually increases, so that a superconducting switch is used in the conventional rectified superconducting current compensator. In the magnetic flux pump type superconducting current compensator, it is more stable than the discrete method according to the speed of the moving magnetic flux by the motor rotation.

In addition, fine current charging (eg, 100 μA) can be easily solved without noise by optimizing the inductance value of the additional magnet compared to the inductance value of the load magnet.

In the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention is not to be determined by the embodiments described above, but will be apparent in the claims as well as equivalent scope.

1 is a diagram illustrating the basic principle of a rotary superconducting power supply.

2 is a diagram illustrating an embodiment of a rotary superconducting power supply.

3 is a view showing another embodiment of a rotary superconducting power supply.

4 is a view illustrating a state in which a cylindrical magnetic flux pump power supply according to an embodiment of the present invention is connected to a load magnet to charge the load magnet.

5 is a view showing a cross-sectional view of a cylindrical magnetic flux pump power supply according to an embodiment of the present invention.

Figure 6 is a view showing a state in which the magnetic flux generated by the AC coil winding in the conventional cylindrical rotary motor.

7 is a view showing the appearance of the AC coil winding wound in a slot according to an embodiment of the present invention.

8 is an illustration showing a region of magnetic flux by moving in a magnetic flux and a mover to penetrate the MgB ₂ superconductor thin film of which penetrate the MgB ₂ thin film according to an embodiment of the invention.

9 is a diagram illustrating a state in which the moving magnetic flux by the AC coil is floated by the magnetic flux by the permanent magnet according to an embodiment of the present invention.

10 is a view showing a state in which the additional magnet is provided at the output terminal of the cylindrical flux pump power supply according to an embodiment of the present invention.

Claims (11)

A permanent magnet core provided with a permanent magnet in the core of the core to generate a magnetic flux complemented by the AC coil to have a '+' value; A superconductor thin film surrounding an outer surface of the permanent magnet core and generating a pumping current by the moving magnetic flux; An iron core cylindrical having the permanent magnet core and the superconductor thin film in an air gap therein, the cylindrical iron core having a plurality of slots formed along an inner circumferential surface thereof; AC coil wound in the slot and generating moving magnetic flux by applying AC current Cylindrical flux pump power supply comprising a. The cylindrical magnetic flux pump power supply of claim 1, wherein the superconductor thin film is formed of a niobium (Nb) or MgB ₂ thin film. 2. The superconducting power supply according to claim 1, wherein each AC coil is wound by pairing two slots. 4. The cylindrical flux pump power supply according to claim 3, wherein each AC coil is wound on a pair of two slots facing each other on opposite inner circumferential surfaces of the cylindrical iron core. 5. A cylindrical cylinder according to claim 4, wherein each AC coil is wound in pairs of two slots facing each other, opposite each other, and then wound in turn in a pair of two slots located opposite each other next. Flux pump power supply. The cylindrical magnetic flux pump power supply of claim 1, wherein the AC coil comprises a first AC coil, a second AC coil, and a third AC coil to which a three-phase AC current is applied. The first AC coil is wound around the first three pairs of slots when the total of 18 slots has a total of six pairs of slots. And a second AC coil wound around the third pair of slots, and a third AC coil wound around the next three pairs of slots. 8. The cylindrical flux pump power supply according to claim 7, wherein one AC coil is wound around each of the pair of slots in turn and wound around three pairs of slots. The method according to claim 8, wherein when the three-phase AC current has a phase sequence of A phase-> B phase-> C phase, A phase is changed from the first AC coil, C phase from the second AC coil, and B phase from the third AC coil. Applied superconducting power supply. 10. The number of turns of the AC coil according to any one of claims 1 to 9, wherein the number of turns of the AC coil is set in consideration of the threshold value at which the phase transition occurs from the superconducting state to the mixed state. Cylindrical flux pump power supply, characterized in that different. 10. The output terminal of any one of claims 1 to 9, wherein an additional magnet having the same inductance as the load magnet charged by the pumping current output of the cylindrical flux pump power supply is provided. Cylindrical flux pump power supply, characterized in that.

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