KR101963824B1 - Wireless charging system and apparatus for superconductor magnetic levitation train using high-temperature superconductor magnet - Google Patents

Abstract

A wireless charging system and apparatus for an inexpensive and stable superconducting magnetic levitation train are provided. A wireless charging system for a superconducting magnetic levitation train according to the present invention comprises a plurality of superconducting wireless charging devices arranged on guide rails installed on both side surfaces along a train rail and a plurality of superconducting And a wireless charging device. The normal-conduction wireless charging device includes an alternating-current power source, one or more normal-conduction transmitting-coil portions for receiving electric power from the alternating-current power source and generating an electric field, and an impedance matching circuit disposed between the power source and the normal- . A superconducting wireless charging apparatus includes a superconducting receiving coil part accommodated in a freezer and receiving power from a transmitting coil, a superconducting magnet accommodated in the freezer, a rectifying circuit converting an alternating current from the superconducting receiving coil into a direct current, And a superconducting switch that is short-circuited when sufficient power is supplied to the superconducting magnet to enter the permanent current mode.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless charging system and apparatus for a superconducting magnetic levitation train using a high-temperature superconducting magnet,

The present invention relates to a wireless charging system and apparatus for a superconducting magnetic levitation train using a high-temperature superconducting magnet, and more particularly, to a wireless charging system and apparatus for a superconducting magnetic levitation train which is inexpensive and stable in a superconducting magnetic levitation train .

Magnetic levitation trains are trains that move by moving a vehicle on a track using the principle of magnetic repulsion. Magnetic levitation trains operate without direct contact with the track, so noise and vibration are very small and can be maintained at a high speed.

In order for a maglev train to move, two forces are required: one to lift the train from the track and one to propel the train in the desired direction.

The method of floating the train on the track can be divided into a magnetic repulsion type using the repulsive force of the magnet anode and a normal phase absorption type using the attraction force between the magnet and the magnetic body. The superconducting aspiration formula using the property to attach to each other is a system suitable for relatively low-speed driving by keeping the height of the trains by varying the attractive force depending on the magnitude of the gap between the electromagnet and the rail. The magnetism repulsion formula uses a repulsive force pushing the same pole of a magnet to float the train in the air. The magnetism repulsion using the superconducting magnet can greatly maintain the levitation force by the strong magnetic field force, and the construction cost for rail production is greatly reduced And can operate stably even at a high speed due to a large injury force

An example of such a superconducting magnetic levitation train is disclosed in Korean Patent No. 1137968, Korean Patent Laid-Open No. 10-2016-0090529, and the like. These superconducting magnetic levitation trains cause superconducting magnets installed on both sides of the train to push up the permanent magnets (N pole, S pole) of the guide rails along the sides of the railroad track, thereby raising the trains. When the propulsion system of the train makes initial propulsion, the linear magnet installed on the guide rail pushes the superconducting magnet in turn, generating a strong propulsion force. Superconducting magnets have higher current density than normal magnets and generate a strong magnetic field to increase the height of the flying height. The larger the flying height, the lower the construction cost and the high speed operation becomes possible.

However, in the conventional superconducting magnetic levitation train, since the superconducting magnet is installed in the low-temperature container filled with the low-temperature refrigerant such as helium, the cooling cost is high and the expensive superconducting magnet is used.

The object of the present invention is to construct a superconducting magnetic levitation train using a high-temperature superconducting magnet, thereby lowering production costs and operating costs. In addition, the present invention solves the problem that the high-temperature superconducting magnet is required to continuously supply current in comparison with the low-temperature superconducting wire because the current decay is large in the permanent mode, and thus the superconducting magnet using the high-temperature superconducting magnet And an object of the present invention is to provide a wireless charging system and apparatus for a magnetic levitation train.

A wireless charging system for a superconducting magnetic levitation train according to an embodiment of the present invention includes a plurality of phase-change wireless charging devices for supplying electric power and disposed on guide rails installed on both sides along a train rail, And a plurality of superconducting wireless charging devices disposed on both sides of the superconducting wireless charging device to charge the plurality of superconducting wireless charging devices by receiving electric power.

The normal charging wireless charging apparatus includes an AC power source, one or more normal conduction transmitting coil portions for receiving electric power from the AC power source to generate an electromagnetic field, and an impedance matching circuit disposed between the power source and the normal conduction transmitting coil portion. . The impedance matching circuit preferably has a circuit configuration in which one inductor is provided at each of the left branch and the right branch of the T-type circuit, and a capacitor is provided at the center branch. At least one of the inductors is a variable inductor. In one embodiment, the inductance of the inductor placed on the left branch is one half of the inductance of the inductor placed on the right branch. Normal-reference ratio of a wireless charging device, impedance matching is reflected to the output terminal of the circuit incoming reflected power value (P _ref) for the measuring step and the measured reflected power value (P _ref) is the input power value (P _in) If not, the inductance value adjustment procedure is terminated. Otherwise, the mutual inductance value (M _Tx-Rx ) between the transmitting coil and the receiving coil is measured, and then the adjusted transmission inductance is the sum of the inductance of the receiving coil part and the mutual inductance And adjusting the inductance value of the impedance matching circuit so as to adjust the inductance of at least one of the inductors of the impedance matching circuit.

A superconducting wireless charging apparatus includes a superconducting receiver coil portion accommodated in a cooling vessel and receiving power from a transmission coil disposed along a railway track, a superconducting magnet accommodated in the freezer and providing a repulsive force for floating the train, And a superconducting switch accommodated in the freezer and short-circuited when sufficient power is supplied to the superconducting magnet to enter the superconducting magnet into the permanent current mode, .

The superconducting receiving coil portion is formed of the AC high temperature superconducting wire, and the superconducting magnet may be formed of the high temperature superconducting wire. In one embodiment, the freezer is filled with refrigerant. In one embodiment, the coolant is only partially filled in the freezer, the superconducting receiver coil is located in the coolant, and the superconducting magnet is located outside the coolant. As the refrigerant, liquid nitrogen may be used. In one embodiment, the rectifier circuit is located outside the freezer.

According to the present invention, since the high-temperature superconducting magnet is used, the cooling cost is low. Also, since the high-temperature superconducting receiver coil is used for supplying the wireless power and accommodated in a cooling container such as a high-temperature superconducting magnet, the installation cost can be reduced while enhancing power supply efficiency. In addition, the inductance value of the impedance matching circuit is changed in real time to maintain a strong resonance phenomenon. As a result, the power and the signal drop period are eliminated between the transmission coils for wireless charging, and the stability can be improved.

1 is a conceptual diagram showing a configuration of a superconducting magnetic levitation train using the high-temperature superconducting magnet according to the present invention.
FIG. 2 is a block diagram showing the configuration of a superconducting magnetic levitation train wireless charging system using the high-temperature superconducting magnet of the present invention.
3 is an equivalent circuit diagram for explaining the operation principle of a wireless charging system for a superconducting magnetic levitation train using the high-temperature superconducting magnet of the present invention.
4 is a circuit diagram showing an example of an impedance matching circuit.
FIG. 5 is a flowchart showing a procedure for adjusting the inductance value of the impedance matching circuit of FIG. 4 during the operation of the superconducting magnetic levitation train.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1 is a conceptual diagram showing a configuration of a superconducting magnetic levitation train using the high-temperature superconducting magnet according to the present invention.

A magnet for magnetic levitation of a train and a plurality of normal conduction transmitting coil units 200 for supplying electric power are provided in a row on a guide rail 300 installed upright on both sides along a train rail. The magnets are arranged, for example, so that the S pole is on the left side and the N pole is on the down side and the opposite side on the right side. A plurality of superconducting wireless charging apparatuses 100 are installed on the side of the superconducting magnetic levitation train T at positions facing the normal conducting coil unit 200 to receive power from the normal conducting coil unit 200. This electric power is supplied to a plurality of superconducting magnets 130 provided on the side surface of the superconducting maglev train T so that the superconducting magnet 130 operates as an electromagnet. The polarity of the superconducting magnet 130 is set to be the same as the polarity of the lower side of the magnet provided on the guide rail 300 as in the case of a general maglev train and the polarity of the magnet and the superconducting magnet 130 provided on the guide rail 300 The vehicle is injured.

The superconducting wireless charging apparatus 100 includes a superconducting receiver coil housed in a cooling vessel. The superconducting receiver coil is disposed at a position opposite to the transmission coil of the normal conduction transmitting coil part 200 and receives power wirelessly by the magnetic field from the normal conduction transmitting coil part 200. Further, even when the train T advances forward, the superconducting receiving coils in each superconducting wireless charging device 100 pass through the transmission coils arranged in a row on the guide rail 300 while facing each other, Power is supplied wirelessly by the magnetic field from the coil.

This will be described in detail with reference to FIG. FIG. 2 is a block diagram showing the configuration of a superconducting magnetic levitation train wireless charging system using the high-temperature superconducting magnet of the present invention.

The superconducting magnetic levitation train wireless charging system of the present invention includes a plurality of superconducting wireless charging devices and a plurality of superconducting wireless charging devices.

The normal charging wireless charging apparatus includes an AC power source 410, one or more normal conduction transmitting coil units 200 receiving power from the AC power source 410 to generate an electric field, an AC power source 410, And an impedance matching circuit (420) disposed between the transmission coil sections (200).

Each of the normal phase transmission coil units 200 is connected to an AC power source 410 through an impedance matching circuit 420 and is supplied with an AC current. One impedance matching circuit 420 may be provided for each AC power source 410, or one impedance matching circuit 420 may be provided for each of the normal conduction transmitting coil sections 200. Also, one phase-conduction transmitting coil section 200 may be connected to each of the alternating-current power sources 410. A magnetic field is generated while the alternating current from the alternating-current power source 410 passes through the transmission coil in the normal-phase transmission coil section 200 via the impedance matching circuit 420. [

A plurality of superconducting wireless charging apparatuses 100 are provided on side surfaces of the superconducting magnetic levitation train T. The superconducting wireless charging apparatus 100 is provided with a cooling vessel 110, and the freezer 110 is filled with liquid refrigerant. The refrigerant used may be a refrigerant such as liquid nitrogen which can maintain the temperature required for high-temperature superconductivity. The refrigerant may be filled in the freezer 110, or may be partially filled. The temperature in the freezer 110 is maintained at, for example, about 100 to 130K. In the freezer (110), a superconducting receiving coil part (120) including a superconducting coil and a high temperature superconducting magnet (130) are accommodated. As the superconducting coil, for example, high temperature superconducting wires for AC (BSCCO, YBCO, etc.) may be used. As the high temperature superconducting magnet 130, for example, high temperature superconducting wires (BSCCO, YBCO) may be used. In an embodiment where the refrigerant is partially filled in the freezer 110, it is preferable that the superconducting receiving coil 120 is located in the coolant and the HTS magnet 130 is located outside the coolant. This is because the performance of the superconducting magnet may deteriorate at a cryogenic temperature.

As the train moves, the superconducting receiver coils pass the front of the superconducting transmission coil, and the alternating current flows to the superconducting receiver coil by the magnetic field generated by the superconducting transmission coil. This alternating current is converted into a direct current by the rectifying circuit 140 and supplied to the high temperature superconducting magnet 130.

The rectifier circuit 140 is preferably located outside the freezer 110. The superconducting switch SW is short-circuited to enter the permanent current mode when a current equal to or higher than a predetermined reference value flows from the rectifying circuit 140 to the high-temperature superconducting magnet 130 (that is, when power of a predetermined reference or more is supplied).

The role of the superconducting switch (SW) can be seen in two major ways. The first is to maintain a persistent current. When sufficient power is supplied to the superconducting magnet 130 through the rectifying circuit 140, the power supplied from the rectifying circuit 140 is turned off and the superconducting switch SW is closed so that the superconducting magnet 130 is charged The generated current generates a stable magnetic field while the current continues to flow through the closed loop formed by the high-temperature superconducting magnet 130 and the superconducting switch SW (only a very small attenuation occurs). As a result, You are injured. However, in the case of high-temperature superconductivity, the current is very small, but current decreases. Therefore, the superconducting magnet 130 must be continuously charged with current. When the current is charged, the superconducting switch SW serves as a terminal for connecting the rectifier circuit 140 . According to the embodiment, the superconducting switch SW can be turned on and off at regular intervals. The period may be appropriately adjusted according to the magnitude of the required charge current.

This operation will be described in detail with reference to FIG. 3 is an equivalent circuit diagram for explaining the operation principle of a wireless charging system for a superconducting magnetic levitation train using the high-temperature superconducting magnet of the present invention.

3, the AC power source 410 is represented by an AC voltage source Vs and an equivalent resistance Rs. The higher the frequency of the AC voltage source Vs is, the more advantageous is the increase of the transmission distance. However, since it may be difficult to rectify the transmitted power, it is preferable to appropriately determine the transmission distance and the rectification performance. But is not limited thereto. The maximum supply power of the AC voltage source Vs can be, for example, several KW, but the present invention is not limited to a specific power magnitude.

The AC power supply 410 supplies the current to the normal conduction transmitting coil part 200 through the impedance matching circuit 420. The configuration of the impedance matching circuit 420 will be described later. In the example of FIG. 3, the normal-conduction transmitting coil part 200 is represented by a normal-phase transmitting coil L ₁ , an equivalent resistance R ₁ and an equivalent capacitance C ₁ . The impedance matching circuit 420 may be connected in parallel with a plurality of normal conduction transmitting coil sections 200. In the example of FIG. 3, two phase-change transmission coils are connected in parallel.

In the example of FIG. 3, the superconducting receiving coil L ₃ , equivalent resistance R ₃ , and equivalent capacitance C ₃ are equivalent circuits of the superconducting receiving coil section 120. A magnetic field is generated when the current I ₁ flows through the normal-conduction transmitting coil L ₁ . A magnetic field is generated in the normal-current transmission coil L ₂ connected in parallel while the current I ₂ flows. When the superconducting receiving coil part 120 passes the part of the main transmission coil part 200 as the train runs and the alternating current is supplied to the superconducting coil L ₃ by the magnetic field generated in the main transmission coil L ₁ Induced flow. The magnitude of the mutual influence due to the magnetic field between the superconducting transmission coil L ₁ and the superconducting coil L ₃ can be expressed by a mutual inductance.

The induced current I ₃ flowing through the superconducting receiver coil L ₃ is converted into a DC current in the rectifier circuit 140 and flows to the high temperature superconducting magnet 130. In FIG. 3, the high-temperature superconducting magnet 130 is represented by its equivalent resistance (R _L ). As the high-temperature superconducting magnet 130, for example, a coil having a number of turns of several hundreds can be used. At this time, the core may not be used.

On the other hand, while the train is moving forward the superconducting receiving coil (L ₃₎ normal-moving away from the transmitting coil (L ₁₎ is normal-go approaches the transmitter coil (L _2). When the superconducting receiving coil (L ₃₎ a normal-conducting held in the range of influence of the magnetic field generated by the transmitting coil (L ₂₎ and the superconducting receiving coil (L _3), the current flows induced by a magnetic field, the induced current, as described above Can be stored in the high-temperature superconducting magnet (130).

As described above, when the superconducting switch SW is open and sufficient power is supplied from the rectifier circuit 140 to the high-temperature superconducting magnet 130, the superconducting switch SW is short-circuited to enter the permanent current mode. The current flowing in the superconducting magnet 130 in the permanent current mode flows through a closed loop composed of the high-temperature superconducting magnet 130 and the superconducting switch SW to generate a stable magnetic field, You are injured.

On the other hand, when a plurality of transmission coils are used, an interval in which the transmission power is reduced rapidly in the gap between the transmission coils necessarily occurs, and the stability of the power and the signal is deteriorated. Therefore, in order to solve this problem, in the present invention, an impedance matching circuit is provided to maintain a strong resonance phenomenon, and as a result, there is no power and signal drop between the transmission coils, and stability can be improved.

In general, various circuits are used as the impedance matching circuit. For example, in an impedance matching circuit using a resistor and an operational amplifier (OP Amp), a resistance value is changed for impedance matching. However, there is a problem that an effective power loss is largely generated by a resistance value. In the present invention, a method of compensating for a fine mutual inductance value caused by a change in position between coils is used to reduce the effective power loss. Such an impedance matching circuit may have a circuit configuration in which one inductor is provided at each branch of the T-shaped circuit as shown in FIG. 4, and a capacitor is provided at the center branch. The capacitors C ₁₁ and C ₁₃ may be variable capacitors capable of changing capacitances or capacitors having fixed capacitance values. One embodiment the left inductance L of the inductance L _mat2 size of _mat1 and right inductor of the inductor are different from each other in and through the change of the combination of L _mat1 value and L value _mat2 maintaining impedance matching between the receiving coil. According to the embodiment, the inductance of either one can be fixed and the other inductance can be changed. In one embodiment, the L _mat1 value is set to be about 1/2 of the L _mat2 value.

In the impedance matching system shown in FIG. 4, when the impedance matching between the coils does not coincide, it is preferable to change the value of the variable inductance L _mat1 and L _mat2 in real time to maintain strong impedance matching. The procedure for maintaining the impedance matching in real time in this way will be described with reference to FIG.

The procedure of FIG. 5 may be performed in a separate control unit (not shown) provided in the impedance matching circuit 420. When a power having a power value P _in is input to the input terminal of the impedance matching circuit 420 (step S51), the control unit measures the reflected power value P _ref reflected from the output terminal of the impedance matching circuit 420 (Step S52). If the measured reflected power value P _ref is not higher than the reference ratio of the input power value P _in (for example, 10%) (NO in step S53), most of the power is transmitted, It is judged that the impedance matching is good and the inductance value adjustment procedure is terminated. In the example of Fig. 5, the reference ratio is set to 10%. On the other hand, if the measured reflected power value P _ref is greater than the reference ratio of the input power value P _in (Yes in step S53), then the return electric power is greater than the reference value and the process goes to step S54, After the adjustment of the mutual inductance value (M _Tx-Rx ) between the coils, the impedance matching circuit (impedance matching circuit and impedance matching circuit) is adjusted so that the adjusted transmission inductance (the total inductance of the impedance matching circuit and the transmission coil part) becomes the reception inductance (Step S55). In the example of Figure 5 also the right side inductor of the impedance matching circuit of the four transmission inductances after (L _mat2) the adjustment by adjusting by ΔL _mat2 (L _Tx + ΔL _mat2) is received, the inductance (L _Rx) + mutual inductance (M _Tx-Rx ), Respectively. As described above, it is possible to adjust both the inductances of the two inductors of the impedance matching circuit according to the embodiment, and to adjust the inductance of one of the two inductors.

After adjusting the inductance as described above, the procedure after step S52 is repeated to make the reflected power value P _ref not to be larger than the reference value.

While the present invention has been described with reference to several embodiments thereof, it is to be understood that the invention is not limited to the specific embodiments thereof, and many changes and modifications may be effected therein without departing from the scope of the invention. It will be understood. For example, although the magnetic levitation train has been described above as an example, the present invention is not limited to a train, and any superconducting repulsion type transportation device is applicable.

100 wireless charging device,
110 Freezer,
120 superconducting receiver nose,
130 High temperature superconducting magnet,
140 rectifier circuit,
200 phase conductivity transmission coil part,
420 Impedance matching circuit.

Claims (4)

A plurality of phase-conduction wireless charging devices for supplying electric power, a plurality of phase-change wireless charging devices disposed on the guide rails installed upright on both sides along the train rails,
And a plurality of superconducting wireless charging devices disposed on both sides of the superconducting magnetic levitation train for supplying power from the plurality of phase-
And,
The normal-charge wireless charging device includes:
A control unit,
An AC power source,
One or more normal-conduction transmitting coil portions for receiving electric power from the alternating-current power source and generating an electric field,
An impedance matching circuit disposed between the power supply and the portion of the normal-
/ RTI >
The superconducting wireless charging apparatus includes:
A superconducting receiver coil portion accommodated in a cooling vessel for receiving power from a transmission coil disposed along a railroad track,
A superconducting magnet housed in the freezer and providing a repulsive force for lifting the train;
A rectifying circuit located outside the freezer and converting an alternating current from the superconducting receiving coil into a direct current;
And a superconducting switch that is accommodated in the freezer and is short-circuited when sufficient power is supplied to the superconducting magnet to enter the permanent current mode of the superconducting magnet.
Respectively,
The impedance matching circuit has a circuit configuration in which one inductor is provided at each of the left branch and the right branch of the T-type circuit, and a capacitor is provided at the center branch.
At least one of the inductors being a variable inductor,
The control unit of the normal-power wireless charging device, while the train is running,
Measuring a reflected power value (P _ref ) reflected from an output terminal of the impedance matching circuit,
If the measured reflected power value P _ref is not higher than the reference ratio of the input power value P _in , the inductance value adjustment procedure is terminated. If the measured reflected power value P _ref is greater than the reference ratio, the mutual inductance value M _Tx- ), And adjusting the inductance value of the impedance matching circuit in real time so that the adjusted transmission inductance becomes a value obtained by adding inductance to the inductance of the receiving coil part
So that the reflected power value (P _ref ) is not greater than the reference value.
The method according to claim 1,
Wherein the step of adjusting the inductance value of the impedance matching circuit adjusts the inductance value of any of the inductors of the left branch or the right branch by a predetermined value.
3. The method according to claim 1 or 2,
Wherein the superconducting receiving coil portion is formed of an AC high temperature superconducting wire and the superconducting magnet is formed of a high temperature superconducting wire.



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