Wireless power supply device for switch driving of medium voltage system and method of 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 manufacturing method thereof, which can supply an insulated power supply required for driving a switch of a 25 kV medium voltage system by using a physically separated power supply coil and power collection coil to ensure a high insulation withstand voltage of 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 driving device (circuit) capable of controlling the gate voltage of the IGBTs and MOSFETs is used.

[0003] Generally, the electrical reference potential of the switch driving 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 driving circuit.

[0004] The insulation voltage source supplied to the conventional switching driving 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 that serves as the winding of a normal transformer), and this parasitic capacitance acts as a path for the common mode current to flow 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 driving 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 high breakdown voltage characteristics and low on-resistance compared to conventional Si semiconductor switching elements. Therefore, SiC semiconductor switching elements have very good characteristics compared to 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 amount per unit time (high dV / dt characteristics), which appears as a demerit in that a large common-mode current can flow through the parasitic capacitance between the primary and secondary windings from the perspective of the drive circuit of the SiC semiconductor element.

[0008] In order to reduce the common-mode current in the switch drive circuit, it is necessary to minimize the parasitic capacitance recognized at both ends of the primary and secondary sides of the isolation transformer. Therefore, research on the design of transformers for reducing the parasitic capacitance of the primary and secondary sides of transformers is being actively published.

[0009] In a switch drive circuit that drives a semiconductor switching element, the most common method for reducing the parasitic capacitance of the isolation transformer for supplying an isolation voltage is to maximize the distance between the primary and secondary windings and the transformer core. While reducing the area between the winding and the core, the distance between the primary winding and the secondary winding is also designed to be maximally large.

[0010] Such an approach brings about the inevitable result of increasing the size of the isolation transformer, and the increase in the size of the transformer causes an increase in the size of the switch drive circuit, which is disadvantageous in terms of cost and system reliability.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0012] The present invention has been made to solve the above problems. By using a power supply coil and a power collection coil that are physically separated, a high insulation withstand voltage of medium voltage, that is, 70 kV level, is ensured, and one object is to supply an insulated power source required for switching drive of a 25 kV medium voltage system.

[0013] Another object of the present invention is to embody miniaturization and weight reduction by reducing the size of the insulation structure by concentrating the electric field strength inside the insulation structure by manufacturing the insulation structure of the power supply coil and the power collection coil by applying epoxy mold and conductive paint.

Means for Solving the Problems

[0014] A wireless power supply device for switching drive of a medium voltage system according to the present invention includes a high-frequency conversion unit for converting an input power supply into an AC power supply, a power supply coil connected to the high-frequency conversion unit for generating an AC magnetic field using the AC power supply, a first insulation structure surrounding the power supply coil, a power collection coil spaced apart from the power supply coil by a predetermined interval for generating AC power by the AC magnetic field radiated from the insulation coil, a second insulation structure surrounding the power collection coil, and a power conversion unit connected to the power collection coil for rectifying and converting the AC power into DC power, wherein the first and second insulation structures include a first mold part for wrapping the power supply coil and the power collection coil with an insulating material, and a first conductive coating layer applied by a conductive substance on the surface of the first mold part.

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

[0016] The gap between the power supply coil and the current collection coil according to the present invention is 2 cm.

[0017] In the first mold part of the first and second insulating structures according to the present invention, first and second lead-out parts for connecting the power supply coil and the high-frequency conversion part and for connecting the current collection coil and the power conversion part are molded.

[0018] The second insulating structure according to the present invention further includes a second mold part that wraps the first mold part of the current collection coil so that the second lead-out part of the current collection coil extends. The surface of the second mold part includes a second conductive coating layer formed by applying a conductive substance.

[0019] The second mold part according to the present invention further includes a support member for supporting the second lead-out part of the current collection coil.

[0020] The second insulating structure according to the present invention further includes a third mold part that is connected to the second mold part and is formed along the length of the second lead-out part of the current collection coil.

[0021] The end of the third mold part according to the present invention further includes a copper plate on which the second lead-out part of the current collection coil is exposed.

[0022] The end of the third mold part according to the present invention further includes fixing wing parts that are expanded on both sides.

[0023] On the other hand, a method for manufacturing a wireless power supply device by molding first and second insulating structures for a power feeding coil and a power collecting coil according to the present invention, comprising: (a) a primary molding step for molding a first mold part that wraps a power feeding coil and a power collecting 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 feeding coil and the power collecting 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 collecting coil and wraps the first mold part of the power collecting 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 collecting coil to form a second conductive coating layer; and (e) a tertiary molding step for connecting an insulating material to the second mold part of the power collecting coil and molding a third mold part of the power collecting coil along the length of the second lead-out part of the power collecting coil.

[0024] The end portion of the third mold part of the power collecting coil according to the present invention is further provided with a copper plate where the second lead-out part of the power collecting 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 ensuring a high dielectric withstand voltage of a medium voltage, that is, 70 kV level, by using physically separated power feeding coil and power collecting coil.

[0026] Further, 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 feeding coil and the power collecting coil by applying epoxy molding and conductive paint.

[0027] In addition, the present invention can increase the operating frequency to 2 MHz and increase the output power to the 100 W level.

[0028] In addition, in the present invention, almost no common-mode current is generated in the power supply device due to the low parasitic capacitance between the power supply coil and the power collection coil.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0030] To explain the present invention, the operational advantages of the present invention, and the objects achieved by the implementation of the present invention, exemplary preferred embodiments of the present invention will be illustrated below and described with reference to these.

[0031] First, the terms used in this application are only used to describe specific embodiments and are not intended to limit the present invention. The singular form can include the plural form unless the context clearly indicates otherwise. Also, in this application, terms such as "including" or "having" are intended to specify the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should not be construed as precluding the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0032] In the description of the present invention, when it is determined that a detailed description of related known configurations or functions may obscure the gist of the present invention, the detailed description thereof will be omitted.

[0033] As shown in FIGS. 1 to 3 and FIG. 6, a wireless power supply device for switch driving of a medium voltage system according to an embodiment of the present invention includes a high-frequency conversion unit 10, a power supply coil 20, a first insulating structure 30, a power collection coil 40, a second insulating structure 50, and a power conversion unit 60.

[0034] First, the wireless power supply device is roughly divided into a wireless power transmission side including the high-frequency conversion unit 10 and the power supply coil 20, and a wireless power reception side including the power collection coil 40 and the power conversion unit 60.

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

[0036] That is, the wireless power transmission side converts the DC voltage from the input power supply 11 into an AC voltage by the high-frequency conversion unit 10 to generate a transmission-side AC voltage, and the power supply coil 20 generates an alternating magnetic field.

[0037] The alternating magnetic field generated on the wireless power transmission side in this way is transmitted to the wireless power reception side.

[0038] The power collection coil 40 on the powerless power receiving side generates wireless power from the alternating magnetic field radiated from the power supply coil 20. The wireless power thus generated by the power collection coil 40 is converted from an alternating voltage to a direct voltage via a power conversion unit, that is, a rectifier 61, and the direct voltage is stepped up or down via a DC / DC converter 63.

[0039] The switch driving unit 70 can output the direct voltage on the wireless power receiving side as a driving voltage V DD in response to a control signal supplied from the outside.

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

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

[0042] Such a wireless power supply device can be used as a power source for switch driving in a medium-voltage system. By using the physically separated power supply coil 20 and power collection coil 40, a design with high insulation breakdown voltage is possible. Also, the parasitic capacitance Ciso between the power supply coil 20 and the power collection coil 40 is very small, and almost no common-mode current Icm flows through this parasitic capacitance.

[0043] FIG. 2 is a circuit diagram of a wireless power supply device for transmitting power to a power supply coil 20 and a power collection coil 40 separated by 2 cm by the wireless power supply device according to the present embodiment.

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

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

[0046] The circuit parameters designed in the present embodiment are as follows.

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

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

[0049] First, the power supply coil 20 includes a rectangular columnar 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. Thus, the power supply coil 20 is composed of an I-shaped core.

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

[0051] Next, the current collecting 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 feeding coil 20.

[0052] Further, it is configured to include 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 feeding coil 20 and the current collecting coil 40 can be composed of any one of a ferrite core, an iron core, and a magnetic powder core (powder core). At this time, in the case of a ferrite core, it may be manufactured with 3F46, which provides excellent performance in the range of 1 MHz to 3 MHz suitable for operation at 2 MHz.

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

[0055] Here, Litz wire means a copper wire in which a plurality of very thin wires coated with enamel (diameter: 0.04 mm / 0.05 mm, etc.) are twisted at a constant pitch, and it is a wire used for high-frequency devices.

[0056] Such Litz wire has a small increase in AC resistance due to high frequency, can suppress the temperature rise of the coil, is very flexible, and thus has good winding workability. Moreover, there is a wide range of arbitrary selection depending on various wire types (total length of the wire, length of solder, etc.). The twist pitch, wire diameter, number of wires, etc. can be arbitrarily selected, and it is lead-free and soldered to a predetermined length for improving workability at the wire end.

[0057] As described above, the specific dimensions of the power supply coil 20 and the power collection coil 40 configured as such are that the first flange portion 25 of the power supply coil 20 and the third flange portion 45 of the power collection coil 40 have the same horizontal and vertical lengths of 66 mm and 64 mm, respectively. However, the height of the power supply coil 20 (the length from the first flange portion 25 to the second flange portion 27) is 40 mm, and the height of the power collection coil 40 (the length from the fourth flange portion 47 to the third flange portion 45) is 35.5 mm, which are different from each other.

[0058] In addition, as described above, the gap between the power supply coil 20 and the power collection coil 40, that is, the air gap is 2 cm.

[0059] In this case, the first flange portion 25 of the power supply coil 20 and the third flange portion 45 of the power collection coil 40 have a cross-sectional area larger than the cross-sectional areas of the first core 21 and the second core 41, respectively. Thereby, the first flange portion 25 and the third flange portion 45 can physically fix the transmission-side core and the reception-side core, and can play various electromagnetic roles such as reduction of parasitic capacitance and increase of power transmission efficiency.

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

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

[0062] That is, step (a) S100 is a primary molding step for molding the first mold portions 31 and 51 that wrap the power supply coil 20 and the power collection coil 40 with a heat-conductive material, respectively (see (a) of FIG. 5). In this case, the first lead portion 29 of the power supply coil 20 is exposed to the first mold portion 31 and connected to the high-frequency conversion unit 10, and the second lead portion 49 of the power collection coil 40 is configured to be exposed to the first mold portion 51. In this way, the first mold portions 31 and 51 of the first and second insulating structures 30 and 50 are molded.

[0063] In this case, as shown in FIG. 6, the first molded portion 31 of the power supply coil 20 can be manufactured to have a horizontal and vertical length of 100 mm each and a height of 50 mm. Also, the first molded portion 51 of the current collection coil 40 can be manufactured to have a horizontal and vertical 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 substance to the surfaces of the first molded portions 31 and 51 of the power supply coil 20 and the current collection coil 40 (see (b) of FIG. 5).

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

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

[0067] (c) Step S300 is a secondary molding step for forming a second molded portion 53 that extends the second lead portion 49 coupled to the current collection coil 40 and wraps the first molded portion 51 of the second insulating structure 50 with an insulating material (see (c) of FIG. 5). At this time, a columnar support member 53a for supporting the lower end portion of the second lead portion 49 of the current collection coil 40 is formed at the upper portion of the second molded portion 53, so that it is desirable to stably arrange the second lead portion 49.

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

[0069] (d) Step S400 is a secondary coating step for forming a second conductive coating layer by applying a conductive substance to the surface of the second mold part 53 (see (d) of FIG. 5). After performing the secondary molding step and the secondary coating step in this way, the current collection coil 40 is grounded to 0V.

[0070] (e) Step S500 is a tertiary molding step for connecting an insulating material to the second mold part 53 and forming a third mold part 55 along the length of the second lead-out part 49 (see (e) of FIG. 5). That is, the third mold part 55 extends from the upper end of the second mold part 53 and is formed in a box shape, and as shown in FIG. 6, the height from the upper surface of the second mold part 53 to the third mold part 55 can be formed to be 180 mm or more. Further, the horizontal and vertical lengths of the third mold part 55 can be manufactured to be 100 mm each.

[0071] As described above, when the molding of the first to third mold parts 55 of the second insulating structure 50 is completed, a copper plate 57 is provided so that the second lead-out part 49 of the current collection coil 40 is exposed at the upper end, that is, the end of the third mold part 55, and a step (f) S600 for installing a fixing wing part 59 developed in the outer direction from the end of the third mold part 55 is performed.

[0072] After going through steps (a) S100 to (f) S600 in this way, the production 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 the present embodiment be manufactured from an insulating material such as epoxy.

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

[0075] The insulating structure of the wireless power supply device for this purpose uses an epoxy mold with high insulation breakdown voltage and a conductive coating layer coated with a conductive paint to prevent electric field leakage, and prevents insulation breakdown due to a high electric field in the air layer, and is an insulating structure for reducing the insulation distance between modules in the wireless power supply device. Thereby, the volume and weight of the system can be reduced, and miniaturization and weight reduction of the device can be realized.

[0076] FIG. 7 shows the result of simulating the insulation breakdown voltage of the insulating structure manufactured as described above.

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

[0078] The wireless power supply device for switch driving in the medium voltage system according to the present embodiment configured as described above can realize the following advantages.

[0079] First, by increasing the operating frequency to 2 MHz and raising the output power to the 100 W level, miniaturization and weight reduction are possible.

[0080] Second, by ensuring an insulation breakdown voltage of 70 kV level, it can be used as an isolated power supply necessary for driving switches in a 25 kV system.

[0081] Third, due to the low parasitic capacitance between the power supply coil 20 and the power collection coil 40, almost no common mode current is 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 insulation structure can be reduced.

[0083] As described above, the present invention has been described with reference to one embodiment shown in the drawings, but this is merely exemplary, and those having ordinary knowledge in the relevant technical field should understand that various modifications and equivalent other embodiments will be possible hereafter.

[0084] Therefore, the true technical protection scope of the present invention should be determined by the technical idea of the appended claims.

Explanation of Reference Numerals

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

Claims

1. A high frequency conversion unit (10) for converting an input power source (11) into an AC power source; a power supply coil (20) connected to the high frequency conversion unit (10) for generating an AC magnetic field using an AC power source; A first insulating structure (30) that encases the power supply coil (20); a current collecting coil (40) spaced a predetermined distance from the power supply coil (20) for generating AC power by an AC magnetic field radiated from an insulating coil; a second insulating structure (50) that encases the current collecting coil (40); a power conversion unit (60) connected to the current collecting coil (40) for rectifying and converting AC power into DC power; The first and second insulating structures (50) are a first molded portion (31) (51) that encases the power supply coil (20) and the power collecting coil (40) with an insulating material; a first conductive coating layer applied to a surface of the first molded part (31)(51) by a conductive material.

2. The power supply coil (20) and the power collecting coil (40) are I-shaped first and second cores (21) (41); and first and second coils (23) (43) wound around the first and second cores (21) (41), The first and second cores (21) and (41) are made of any one of a ferrite core, an iron core, and a magnetic powder core, 2. The wireless power supply device for driving a switch in a medium voltage system according to claim 1, wherein the first and second coils (23, 43) are made of a Litz wire or a magnet wire.

3. 2. The wireless power supply device for driving a switch in a medium voltage system according to claim 1, wherein the gap between the power supply coil (20) and the power collecting coil (40) is 2 cm.

4. 2. The wireless power supply device for driving a switch in a medium voltage system according to claim 1, wherein first and second lead-out portions (29) (49) for connecting the power supply coil (20) and the high frequency conversion unit (10) and for connecting the collecting coil (40) and the power conversion unit (60) are molded in the first molded portions (31) (51) of the first and second insulating structures (30) (50).

5. the second insulating structure (50) further includes a second molded portion (53) that encases the first molded portion (51) of the current collecting coil (40) so that a second lead portion (49) of the current collecting coil (40) extends therethrough; 5. The wireless power supply device for driving a switch in a medium voltage system according to claim 4, wherein a surface of the second molded part (53) includes a second conductive coating layer formed by applying a conductive material.

6. 6. The wireless power supply device for driving a switch in a medium voltage system according to claim 5, wherein the second molded portion (53) further comprises a support member (53a) for supporting the second lead-out portion (49) of the current collecting coil (40).

7. 7. The wireless power supply device for driving a switch in a medium voltage system according to claim 6, wherein the second insulating structure (50) further comprises a third molded portion (55) connected to the second molded portion (53) and formed along a length of the second lead-out portion (49) of the current collecting coil (40).

8. 8. The wireless power supply device for driving a switch in a medium voltage system as set forth in claim 7, further comprising a copper plate (57) at an end of the third molded portion (55) from which the second lead-out portion (49) of the current collecting coil (40) is exposed.

9. 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 collector coil (40), comprising: (a) a primary molding step (S100) for molding a first molded part (31, 51) for wrapping the power supply coil (20) and the current collecting coil (40) with an insulating material; (b) a first coating step (S200) for coating a conductive material on the surfaces of the first molded parts (31, 51) of the power supply coil (20) and the power collecting coil (40) to form a first conductive coating layer; (c) a secondary molding step (S300) for molding a second molded part (53) from which a second lead part (49) coupled to the current collecting coil (40) extends and which encases the first molded part (51) with an insulating material; (d) a second coating step (S400) for coating a conductive material on the surface of the second mold part (53) to form a second conductive coating layer; (e) a third molding step (S500) in which an insulating material is connected to the second molded portion (53) and a third molded portion (55) is molded along the length of the second lead-out portion (49); 2. A method for manufacturing a wireless power supply device for driving a switch in a medium voltage system, comprising:

10. 10. The method for manufacturing a wireless power supply device for driving a switch in a medium voltage system as set forth in claim 9, wherein an end of the third molded part (55) is further provided with a copper plate (57) from which the second lead-out part (49) of the collecting coil (40) is exposed.

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