Wireless power supply device for driving switches in a medium-voltage system and method for manufacturing the same

Abstract

To provide an insulated power supply required for switch driving of a 25 kV medium voltage system.SOLUTION: A wireless power supply device for switch driving of a medium voltage system according to an embodiment includes: a high frequency conversion unit for converting input power into AC power; a feed coil connected to the high frequency conversion unit to generate an AC magnetic field by using AC power; a first insulating structure surrounding the feed coil; a collector coil spaced apart from the feed coil by a predetermined distance to generate AC power by an AC magnetic field radiated from an insulation coil; a second insulating structure surrounding the collector coil; and a power conversion unit connected to the collector coil to rectify and convert AC power into DC power. The first and second insulating structures each include a first molding portion that surrounds the feed coil and the collector coil with an insulating material, and a first conductive coating layer applied by a conductive material on a surface of the first molding portion.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wireless power supply device for driving a switch of a medium voltage system and a method for manufacturing the same, which can supply an insulated power source required for driving a switch of a 25 kV medium voltage system by using physically separated power supply coils and power collection coils to ensure a high insulation withstand voltage at a medium voltage, that is, 70 kV level.

Background Art

[0002] In order to drive semiconductor switching elements such as IGBTs and MOSFETs used in power conversion, a switch drive device (circuit) capable of controlling the gate voltage of the IGBTs and MOSFETs is used.

[0003] Generally, the electrical reference potential of the switch drive circuit is connected to the potential of the source terminal of the semiconductor switching element. The potential of the source terminal of the switching element can be quickly changed depending on the on / off state of the switch. Therefore, an independent insulation voltage is required for the switch drive circuit.

[0004] The insulation voltage source supplied to the conventional switching drive circuit is supplied via a DC / DC converter using an isolation transformer. The transformer used for this has a parasitic capacitance generated with a transformer core interposed between the windings of the primary and secondary transformers (or the pattern of the PCB serving as the role of the winding of a normal transformer), and this parasitic capacitance acts as a path through which a common mode current flows due to the common mode voltage between the primary side voltage and the secondary side voltage of the transformer.

[0005] The common mode current can generate distortion of the signal for driving the semiconductor switching element in the switch drive circuit. The distortion of the switching signal may cause malfunction of the semiconductor switching element and may burn out the semiconductor switching element.

[0006] In recent years, with the development of power semiconductor technology, the commercialization of SiC semiconductor switching elements has been rapidly progressing. SiC semiconductor switching elements have characteristics such as higher voltage withstand capability and lower conduction resistance compared to conventional Si semiconductor switching elements. Therefore, SiC semiconductor switching elements have significantly better characteristics than Si semiconductor switching elements in terms of switching loss and conduction loss.

[0007] However, the high-speed switching characteristics of SiC semiconductor switching elements result in a high voltage change per unit time (high dV / dt characteristics), which, from the perspective of the SiC semiconductor element's drive circuit, manifests as a disadvantage in that a large amount of common-mode current can flow through the parasitic capacitance between the primary and secondary windings mentioned above.

[0008] To reduce common-mode current in switch drive circuits, the parasitic capacitance at both the primary and secondary sides of an isolated transformer must be minimized. Therefore, research on transformer design aimed at reducing parasitic capacitance on the primary and secondary sides is being actively published.

[0009] In switch drive circuits that drive semiconductor switching elements, the most common method for reducing the parasitic capacitance of an isolated transformer that supplies the isolation voltage is to maximize the distance between the primary and secondary windings and the transformer core. This involves reducing the area between the windings and the core, and designing the distance between the primary and secondary windings to be as large as possible.

[0010] This approach inevitably leads to an increase in the size of the isolated transformer, which in turn increases the size of the switch drive circuit, resulting in disadvantages in terms of cost and system reliability. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Korean Registered Patent Publication No. 10-2401160 [Overview of the project] [Problems that the invention aims to solve]

[0012] The present invention was made to solve the aforementioned problems, and one of its objectives is to supply an isolated power supply necessary for switching a 25kV medium voltage system by using a physically separated power supply coil and current collection coil, thereby ensuring a high dielectric strength at a medium voltage level, i.e., 70kV.

[0013] Another objective of this invention is to achieve miniaturization and weight reduction by manufacturing the insulating structures of the power supply coil and current collection coil by epoxy molding and the application of conductive paint, thereby concentrating the strength of the electric field inside the insulating structure and reducing the size of the insulating structure. [Means for solving the problem]

[0014] The wireless power supply device for driving a switch in a medium-voltage system according to the present invention comprises: a high-frequency conversion unit for converting an input power source into an AC power source; a power supply coil connected to the high-frequency conversion unit for generating an AC magnetic field using the AC power source; a first insulating structure enclosing the power supply coil; a current collector coil spaced a predetermined distance from the power supply coil for generating AC power by an AC magnetic field radiated from the insulating coil; a second insulating structure enclosing the current collector coil; and a power conversion unit connected to the current collector coil for rectifying and converting the AC power to DC power. The first and second insulating structures are characterized by comprising: a first molded portion enclosing the power supply coil and the current collector coil with an insulating material; and a first conductive coating layer applied to the surface of the first molded portion with a conductive substance.

[0015] The power supply coil and current collection coil according to the present invention include I-shaped first and second cores and first and second coils wound around the first and second cores, wherein the first and second cores are composed of one of a ferrite core, an iron core, and a magnetic powder core, and the first and second coils are composed of litz wire or magnet wire.

[0016] The present invention is characterized in that the gap between the power supply coil and the current collection coil is 2 cm.

[0017] The first molded portion of the first and second insulating structures according to the present invention is characterized in that first and second lead-out portions for connecting the power supply coil and the high-frequency conversion unit, and for connecting the current collection coil and the power conversion unit are molded into the first molded portion.

[0018] The second insulating structure according to the present invention further includes a second molded portion that encloses the first molded portion of the current collector coil such that a second lead portion of the current collector coil extends from it, and the surface of the second molded portion includes a second conductive coating layer formed by applying a conductive material.

[0019] The second mold portion according to the present invention is further provided with a support member for supporting the second lead portion of the current collector coil.

[0020] The second insulating structure according to the present invention is characterized by further including a third molded portion connected to the second molded portion and formed along the length of the second lead portion of the current collector coil.

[0021] The present invention is characterized in that the end of the third mold portion is further provided with a copper plate on which the second lead-out portion of the current collector coil is exposed.

[0022] The present invention is characterized in that the end of the third mold portion is further provided with fixing wing portions that are extended on both sides.

[0023] On the one hand, a method for manufacturing a wireless power supply device by molding first and second insulating structures for a power supply coil and a power collection coil according to the present invention, comprising: (a) a primary molding step for molding a first mold part that wraps the power supply coil and the power collection coil with an insulating material; (b) a primary coating step for applying a conductive substance to the surface of the first mold part of the power supply coil and the power collection coil to form a first conductive coating layer; (c) a secondary molding step for molding a second mold part that extends a second lead-out part coupled to the power collection coil and wraps the first mold part of the power collection coil with an insulating material; (d) a secondary coating step for applying a conductive substance to the surface of the second mold part of the power collection coil to form a second conductive coating layer; (e) a tertiary molding step for connecting an insulating material to the second mold part of the power collection coil and molding a third mold part of the power collection coil along the length of the second lead-out part of the power collection coil.

[0024] The end of the third mold part of the power collection coil according to the present invention is further provided with a copper plate on which the second lead-out part of the power collection coil is exposed.

Advantages of the Invention

[0025] The wireless power supply device and its manufacturing method for switch driving of a medium voltage system according to the present invention can supply an insulated power source required for switch driving of a 25 kV medium voltage system by using physically separated power supply and power collection coils and ensuring a high insulation withstand voltage of medium voltage, that is, 70 kV level.

[0026] In addition, the present invention can embody miniaturization and weight reduction by reducing the size of the insulating structure by concentrating the electric field strength inside the insulating structure by manufacturing the insulating structures of the power supply coil and the power collection coil by applying epoxy molding and conductive paint.

[0027] Furthermore, the present invention can increase the operating frequency to 2 MHz and raise the output power to a level of 100 W.

[0028] Furthermore, the present invention virtually eliminates common-mode current in the power supply device due to the low parasitic capacitance between the power supply coil and the current collection coil. [Brief explanation of the drawing]

[0029] [Figure 1] This is a conceptual diagram showing a wireless power supply device for driving switches in a medium-voltage system according to one embodiment of the present invention. [Figure 2] This is a circuit diagram showing a wireless power supply device according to one embodiment of the present invention. [Figure 3] This is a perspective view showing the power supply coil and current collection coil of a wireless power supply device according to one embodiment of the present invention. [Figure 4] This is a flowchart showing a method for manufacturing an insulating structure for a power supply coil and a current collection coil of a wireless power supply device according to one embodiment of the present invention. [Figure 5] This is a process diagram showing the manufacturing process for the insulating structures of the power supply coil and current collection coil of a wireless power supply device according to one embodiment of the present invention. [Figure 6] This is a detailed diagram showing the insulating structure of a wireless power supply device according to one embodiment of the present invention. [Figure 7] This figure shows an electric field simulation of the insulating structure of a wireless power supply device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0030] To illustrate the present invention, its operational advantages, and the objectives to be achieved by implementing the present invention, preferred embodiments of the present invention will be illustrated and described below with reference to them.

[0031] First, the terms used in this application are used solely to describe specific embodiments and are not intended to limit the invention. A singular expression may include plural expressions unless they are clearly different in context. Furthermore, terms such as “includes” or “having” in this application are intended to specify the presence of features, figures, stages, operations, components, parts, or combinations thereof as described in the specification, and should not be understood to preemptively exclude the presence or possibility of adding one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0032] In describing the present invention, if it is determined that a specific description of a related known configuration or function would obscure the gist of the invention, such detailed description will be omitted.

[0033] As shown in Figures 1 to 3 and Figure 6, a wireless power supply device for switching a medium-voltage system according to one embodiment of the present invention comprises a high-frequency conversion unit 10, a power supply coil 20, a first insulating structure 30, a current collector coil 40, a second insulating structure 50, and a power conversion unit 60.

[0034] First, a wireless power supply device can be broadly divided into a wireless power transmitting side consisting of a high-frequency conversion unit 10 and a power supply coil 20, and a wireless power receiving side consisting of a current collection coil 40 and a power conversion unit 60.

[0035] The wireless power generated on the wireless power receiving side can be output as a drive voltage by the switch drive unit 70 via the wireless power receiving side.

[0036] In other words, the wireless power transmitting side converts the DC voltage from the input power supply 11 into an AC voltage using the high-frequency conversion unit 10 to generate a transmitting AC voltage, and the power supply coil 20 generates an AC magnetic field.

[0037] In this way, the alternating magnetic field generated on the wireless power transmitting side is transmitted to the wireless power receiving side.

[0038] The current collector coil 40 on the powerless power receiving side generates radio power from the alternating magnetic field radiated from the power supply coil 20. The radio power generated in the current collector coil 40 is converted from an alternating voltage to a direct current voltage via a power conversion unit, i.e., a rectifier 61, and the direct current voltage is then boosted or depressurized via a DC / DC converter 63.

[0039] The switch drive unit 70 responds to an externally supplied control signal by driving the DC voltage of the wireless power receiving side to a drive voltage V DD It can be output as follows.

[0040] As described above, in this embodiment, the wireless power supply device has an dielectric strength of 70kV level, and as shown in Figure 1, the input voltage V in The voltage is 48Vdc and is converted to a high-frequency AC using a high-frequency conversion unit 10 (high-frequency DC / AC inverter 13) that switches to 2MHz. A power supply coil 20 is connected to the high-frequency conversion unit 10, and power is transmitted to a current collector coil 40 located 2cm apart using the high-frequency current generated by the high-frequency conversion unit 10.

[0041] At this time, power can be transmitted up to a maximum of 100W. The current collector coil 40 is connected to the rectifier 61 of the power conversion unit 60, which converts 2MHz alternating current (AC) to direct current (DC), and the output is connected to the DC / DC converter 63 of the power conversion unit 60 to maintain a constant voltage.

[0042] Such wireless power supply devices can be used as power sources for switch driving in medium-voltage systems. By using physically separated power supply coils 20 and 40, a design with high dielectric strength is possible. Furthermore, the parasitic capacitance Ciso between the power supply coil 20 and the current collector coil 40 is very small, and the common-mode current Icm flowing through this parasitic capacitance is almost nonexistent.

[0043] Figure 2 is a circuit diagram of a wireless power supply device according to this embodiment for transmitting power to a power supply coil 20 and a current collection coil 40 that are separated by 2 cm.

[0044] The input power supply 11 is a high-frequency DC / AC inverter 13 that converts 48Vdc to 2MHz AC, where Ltx and Lrx are the magnetic inductances of the feed coil 20 and the current collector coil 40. k is the coupling coefficient between the feed coil 20 and the current collector coil 40, and can have a value of about 0.16 with a 2cm air gap.

[0045] Lm, Cm, and Ctx may be further connected to the power supply coil 20 as a resonant circuit, and Crx may be further connected to the current collector coil 40 as a resonant circuit. Rtx, Rrx, and Rm are the parasitic resistances of the power supply coil 20, current collector coil 40, and compensation circuit, respectively, and RL is the equivalent load resistance.

[0046] The circuit parameters designed in this embodiment are as follows:

[0047] Ltx=6.5μH, Ctx=974pF, Rtx=0.15Ω, Lrx=4.2μH, Crx=1.5nF, Rrx=0.06Ω, Lm=1.2μH, Cm=5nF, Rm=0.1Ω, RL=7.3Ω.

[0048] The power supply coil 20 and the current collection coil 40 according to this embodiment can be manufactured as shown in Figure 3.

[0049] First, the power supply coil 20 is composed of a rectangular prism-shaped first core 21, a first flange portion 25 connected to the lower end of the first core 21, and a second flange portion 27 connected to the upper end of the first core 21. Therefore, the power supply coil 20 is composed of an I-shaped core.

[0050] Furthermore, it includes a first coil 23 wound around the lower end of the first core 21.

[0051] Next, the current collection coil 40 may also be an I-shaped core composed of a second core 41, a third flange portion 45, and a fourth flange portion 47, similar to the power supply coil 20.

[0052] It also includes a second coil 43 wound around the upper end of the second core 41.

[0053] In this case, the I-shaped cores of the power supply coil 20 and the current collector coil 40 can be made of one of the following: a ferrite core, an iron core, or a magnetic powder core (powder core). In the case of a ferrite core, it may be manufactured using 3F46, which provides excellent performance in the 1MHz to 3MHz range suitable for 2MHz operation.

[0054] Furthermore, the first and second coils 23 and 43 can be wound with Litz wire or magnet wire, respectively.

[0055] Here, Litz wire refers to a copper wire made by twisting together multiple extremely thin, enamel-coated wires (diameter: 0.04 mm / 0.05 mm, etc.) at a constant pitch, and is used in high-frequency devices.

[0056] Such Litz wire exhibits minimal increase in AC resistance due to high frequencies, suppresses coil temperature rise, and is highly flexible, resulting in excellent winding workability. Furthermore, it offers a wide range of choices depending on the type of wire (total wire length, solder length, etc.). The twist pitch, wire diameter, and number of strands can be arbitrarily selected, and the wire ends are soldered to a predetermined length with lead-free solder for improved workability.

[0057] As described above, the specific dimensions of the power supply coil 20 and the current collection coil 40 are as follows: the first flange portion 25 of the power supply coil 20 and the third flange portion 45 of the current collection coil 40 are identical in width and length, at 66 mm and 64 mm, respectively. However, the height of the power supply coil 20 (length from the first flange portion 25 to the second flange portion 27) is 40 mm, and the height of the current collection coil 40 (length from the fourth flange portion 47 to the third flange portion 45) is 35.5 mm, which are different from each other.

[0058] As mentioned above, the gap between the power supply coil 20 and the current collection coil 40, i.e., the air gap, is 2 cm.

[0059] In this case, the cross-sectional areas of the first flange portion 25 of the power supply coil 20 and the third flange portion 45 of the current collection coil 40 are larger than the cross-sectional areas of the first core 21 and the second core 41, respectively. As a result, the first flange portion 25 and the third flange portion 45 can physically fix the transmitting core and the receiving core, and can perform various electromagnetic roles such as reducing parasitic capacitance and increasing power transmission efficiency.

[0060] Figures 4 and 5 show the manufacturing method and fabrication process of an insulating structure in a wireless power supply device according to one embodiment of the present invention.

[0061] First, as shown in Figure 4, the method for manufacturing a wireless power supply device according to one embodiment of the present invention, that is, the method for manufacturing an insulating structure, is as follows.

[0062] In other words, (a) step S100 is a primary molding step for forming the first molded portions 31 and 51 that enclose the power supply coil 20 and the current collection coil 40 with heat transfer material, respectively (see Figure 5(a)). In this case, the power supply coil 20 has a first lead portion 29 that is exposed to the first molded portion 31 and connected to the high-frequency conversion unit 10, and the current collection coil 40 has a second lead portion 49 that is exposed to the first molded portion 51. In this way, the first molded portions 31 and 51 of the first and second insulating structures 30 and 50 are formed.

[0063] In this case, as shown in Figure 6, the first molded portion 31 of the power supply coil 20 can be manufactured with a width and length of 100 mm each and a height of 50 mm. The first molded portion 51 of the current collector coil 40 can be manufactured with a width and length of 70 mm each and a height of 40 mm.

[0064] (b) Step S200 is a primary coating step for forming a first conductive coating layer by applying a conductive material to the surfaces of the first molded portions 31 and 51 of the power supply coil 20 and the current collection coil 40 (see Figure 5(b)).

[0065] After the primary molding and primary coating stages are completed in this manner, the power supply coil 20 is grounded to 0V, and the current collection coil 40 is grounded to high voltage. In this case, the manufacturing of the first insulating structure 30 for the power supply coil 20 is completed.

[0066] Subsequently, steps (c) S300 to (f) S600 are processes for manufacturing a second insulating structure 50 for the current collector coil 40.

[0067] (c) Stage S300 is a secondary molding stage for forming a second molded portion 53 that extends from the second lead portion 49 coupled to the current collector coil 40 and encloses the first molded portion 51 of the second insulating structure 50 with insulating material (see Figure 5(c)). At this time, it is desirable to stably position the second lead portion 49 by forming a cylindrical support member 53a on the upper part of the second molded portion 53 to support the lower end of the second lead portion 49 of the current collector coil 40.

[0068] In this case, as shown in Figure 6, the horizontal and vertical lengths of the second molded portion 53 are each 100 mm, and the height can be manufactured to 80 mm. In particular, the first molded portion 51 of the second insulating structure 50 is configured to be non-contact with the second molded portion 53, and the lower part may be manufactured to be floating so as to maintain a 2 cm gap between the power supply coil 20 and the current collection coil 40, and a distance of 25 mm is maintained between the upper surface of the first molded portion 51 and the upper surface of the second molded portion 53. In addition, the support member 53a positioned on the outer upper surface of the second molded portion 53 can be manufactured to a height of 30 mm.

[0069] (d) Step S400 is a secondary coating step in which a conductive material is applied to the surface of the second molded portion 53 to form a second conductive coating layer (see Figure 5(d)). After performing the secondary molding step and the secondary coating step in this manner, the current collector coil 40 is grounded to 0V.

[0070] (e) Stage S500 is a tertiary molding stage for connecting an insulating material to the second molded portion 53 and molding the third molded portion 55 along the length of the second drawout portion 49 (see Figure 5(e)). That is, the third molded portion 55 is formed in a box shape extending from the upper end of the second molded portion 53, and as shown in Figure 6, the height of the third molded portion 55 from the upper surface of the second molded portion 53 can be molded to be 180 mm or more. The horizontal and vertical lengths of the third molded portion 55 can also be manufactured to be 100 mm each.

[0071] As described above, once the molding of the first to third molded portions 55 of the second insulating structure 50 is completed, step (f) S600 is performed to install the copper plate 57 and the fixing wing portion 59 which is extended outward from the end of the third molded portion 55, so that the second lead portion 49 of the current collection coil 40 is exposed at the upper end, i.e., end of the third molded portion 55.

[0072] In this way, by going through steps (a) S100 to (f) S600, the manufacturing of the first insulating structure 30 for the power supply coil 20 and the second insulating structure 50 for the current collection coil 40 can be completed.

[0073] In particular, it is desirable that the first and second insulating structures 30 and 50 according to this embodiment be manufactured from an insulating material such as epoxy.

[0074] The insulating structure according to this embodiment is an insulating structure applied to a wireless power supply device for switch driving of a 25kV medium voltage system for railway vehicles, and is an insulating structure for a wireless power supply device having dielectric strength at the 70kV level.

[0075] The insulating structure of the wireless power supply device for this purpose uses epoxy mold with high dielectric strength and a conductive coating layer coated with conductive paint to prevent electric field leakage. This prevents dielectric breakdown due to high electric fields in the air layer and reduces the insulating distance between modules in the wireless power supply device. As a result, the volume and weight of the system can be reduced, enabling miniaturization and weight reduction of the device.

[0076] Figure 7 shows the results of a simulation of the dielectric strength of the insulating structure manufactured as described above.

[0077] In other words, when the potential difference between the low-voltage side, the power supply coil 20, and the high-voltage side, the current collection coil 40, is 70kV, the electric field is concentrated inside the epoxy insulating structure. The strength of the electric field outside the insulating structure is 3MV / m or less, which is lower than the dielectric strength of air, and it can be confirmed that dielectric breakdown does not occur even in the presence of air.

[0078] The wireless power supply device for driving switches in a medium-voltage system according to this embodiment, configured as described above, can embody the following advantages.

[0079] Firstly, by increasing the operating frequency to 2MHz and raising the output power to 100W, it is possible to miniaturize and lighten the device.

[0080] Secondly, by ensuring dielectric strength at a 70kV level, it can be used as an isolated power supply required for driving switches in a 25kV system.

[0081] Third, due to the low parasitic capacitance between the power supply coil 20 and the current collection coil 40, common-mode current is hardly generated in the wireless power supply device.

[0082] Fourth, by concentrating the electric field strength inside the insulator through the application of epoxy mold and conductive paint, the size of the insulating structure can be reduced.

[0083] Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely illustrative, and a person with ordinary skill in the art will understand that a variety of modifications and equivalent other embodiments are possible therefrom.

[0084] Therefore, the true scope of technical protection of the present invention must be determined by the technical concept of the appended claims. [Explanation of Symbols]

[0085] 10: High-frequency conversion section 11: Input power 13: High-frequency DC / AC inverter 20: Power supply coil 21: The first core 23: The first coil 25: First flange section 27: Second flange section 29: First drawer section 30: First insulating structure 31: First mold section 40: Current collection coil 41: The second core 43: The second coil 45: Third flange section 47: Fourth flange section 49: Second drawer section 50: Second insulating structure 51: First mold section 53: Second mold section 53a: Support member 55: Third mold section 57: Copper plate 59: Fixed wing part 60: Power conversion unit 61: Rectifier 63: DC / DC converter 70: Switch drive unit

Claims

1. A high-frequency conversion unit (10) for converting the input power supply (11) into an AC power supply, A power supply coil (20) is connected to the aforementioned high-frequency conversion unit (10) to generate an AC magnetic field using an AC power source, The first insulating structure (30) encloses the power supply coil (20), The power supply coil (20) and the current collection coil (40) are separated by a predetermined distance and generate AC power by the AC magnetic field radiated from the insulating coil, A second insulating structure (50) encloses the current collection coil (40), The system includes a power conversion unit (60) connected to the current collection coil (40) for rectifying and converting AC power to DC power, The first and second insulating structures (30) (50) are, The first molded parts (31) (51) enclose the power supply coil (20) and the current collection coil (40) with an insulating material, The first conductive coating layer is applied to the surface of the first mold portion (31) (51) using a conductive material, and comprises A second lead-out portion (49) for connecting the current collection coil (40) and the power conversion unit (60) is molded into the first molded portion (51) of the second insulating structure (50). The second insulating structure (50) further includes a second molded portion (53) that encloses the first molded portion (51) of the current collector coil (40) such that the second lead portion (49) of the current collector coil (40) extends from it. A wireless power supply device for driving a switch in a medium-voltage system, characterized in that the surface of the second molded portion (53) includes a second conductive coating layer formed by applying a conductive material.

2. The power supply coil (20) and the current collection coil (40) are, I-shaped first and second cores (21) (41), It comprises first and second coils (23) (43) wound around the first and second cores (21) (41), The first and second cores (21) (41) are composed of one of a ferrite core, an iron core, and a magnetic powder core. The wireless power supply device for switching a medium-voltage system according to claim 1, characterized in that the first and second coils (23) (43) are composed of Litz wire or magnet wire.

3. The wireless power supply device for switching a medium-voltage system according to claim 1, characterized in that the gap between the power supply coil (20) and the current collection coil (40) is 2 cm.

4. A wireless power supply device for switch driving of a medium voltage system according to claim 1, characterized in that a first molded portion (31) of the first insulating structure (30) has a first lead portion (29) molded into it for connecting the power supply coil (20) and the high-frequency conversion unit (10).

5. The wireless power supply device for switch driving of a medium voltage system according to claim 1, characterized in that the second molded portion (53) is further provided with a support member (53a) for supporting the second lead portion (49) of the current collection coil (40).

6. The wireless power supply device for switching a medium-voltage system according to claim 5, wherein the second insulating structure (50) is connected to the second molded portion (53) and further includes a third molded portion (55) formed along the length of the second lead portion (49) of the current collector coil (40).

7. The wireless power supply device for switching a medium-voltage system according to claim 6, further comprising a copper plate (57) at the end of the third molded portion (55) through which the second lead-out portion (49) of the current collection coil (40) is exposed.

8. A method for manufacturing a wireless power supply device by molding first and second insulating structures (30, 50) for a power supply coil (20) and a current collection coil (40), (a) A primary molding step (S100) for forming a first molded portion (31, 51) that encloses the power supply coil (20) and the current collection coil (40) with an insulating material, (b) A primary coating step (S200) for forming a first conductive coating layer by applying a conductive material to the surface of the first molded portions (31, 51) of the power supply coil (20) and the current collection coil (40), (c) A second molding step (S300) for forming a second molded portion (53) that extends from the current collection coil (40) and encloses the first molded portion (51) with insulating material, (d) A secondary coating step (S400) for applying a conductive material to the surface of the second mold portion (53) to form a second conductive coating layer, (e) A third molding step (S500) is performed to form a third molded portion (55) along the length of the second drawout portion (49), in which an insulating material is connected to the second molded portion (53), A method for manufacturing a wireless power supply device for switching a medium-voltage system, characterized by comprising:

9. A method for manufacturing a wireless power supply device for switch driving of a medium voltage system according to claim 8, characterized in that the end of the third molded portion (55) is further provided with a copper plate (57) on which the second lead portion (49) of the current collection coil (40) is exposed.

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