DC capacitor fixing structure of sub-module

Abstract

The present invention relates to a DC capacitor fixing structure of a sub-module, in which a spring member is installed inside a bushing body of a spring bushing and fitted and coupled to the outer circumferential surface of a capacitor terminal, thus making it easy to detach and attach a busbar and the capacitor terminal, and therefore reducing assembly and disassembly times during inspection and repair work on the sub-module.

Description

DC capacitor fixed structure of submodule

[0001] The present invention relates to a DC capacitor fixing structure of a sub-module, and relates to a DC capacitor fixing structure of a sub-module in which a spring bushing is detachably fitted into a capacitor terminal, thereby facilitating assembly and disassembly of the power module portion and the DC capacitor portion of the sub-module.

[0002] Typically, a high-voltage direct current (HVDC) transmission system converts alternating current (AC) power generated at power plants into direct current (DC), transmits it, and then reconverts it to AC at receiving points to supply power. Compared to AC transmission systems, HVDC systems exhibit lower losses, offer greater transmission efficiency, and improve stability through grid separation. Furthermore, they suffer from fewer inductive interference, making them advantageous for long-distance power transmission.

[0003] This ultra-high voltage direct current transmission system is installed in a structure called a converter module, which consists of multiple sub-modules and multiple layers, each up to 10 meters high. The sub-module is largely composed of a power module section and a DC capacitor section. Inspection and repair of the sub-module must be performed with the power module section and the DC capacitor section separated from each other.

[0004] The power module section and DC capacitor section of the above sub-module can be completely separated after disassembling the screws and washers attached to the capacitor terminals.

[0005] This separation structure of the power module section and the DC capacitor section is disclosed in Korean Patent Publication No. 10-2018-0121132.

[0006] The conventional power module unit and DC capacitor unit are configured such that the capacitor terminal is inserted through the bus bar, and a washer and a nut are screwed onto the capacitor terminal. In order to separate the power module unit and the DC capacitor unit, the worker can fix and disassemble the power module unit and the DC capacitor unit by attaching and disassembling the washer and nut.

[0007] Since the power module section and the DC capacitor section are assembled and disassembled through a screw connection method using washers and nuts, there is a problem in that it takes a long time to assemble and disassemble a large number of washers and nuts.

[0008] In addition, there is a problem that the worker may lose the washers and nuts during the process of assembling and disassembling the washers and nuts, which may cause a failure of the submodule due to the lost washers and nuts, and which may reduce work efficiency due to the lost washers and nuts.

[0009] A prior art document that has the problems described above is Republic of Korea Patent Publication No. 10-2018-0121132.

[0010] Accordingly, the purpose of the present invention is to solve the problems of the prior art as described above, and to provide a DC capacitor fixing structure of a sub-module in which a spring bushing is detachably fitted to a capacitor terminal, thereby facilitating assembly and disassembly of the power module portion and the DC capacitor portion of the sub-module.

[0011] According to a feature of the present invention for achieving the above-described object, a DC capacitor fixing structure of a sub-module according to the present invention includes a power module section including a switching element, a DC capacitor section connected to the power module section, storing energy and maintaining a voltage of a certain level, a capacitor terminal protrudingly formed on one surface of the DC capacitor section and connected to the power module section to supply power, a bus bar having one side connected to the power module section and the other side connected to the DC capacitor section, and a spring bushing fixedly connected to the bus bar and detachably installed on the capacitor terminal to fix and release the bus bar and the capacitor terminal.

[0012] The above spring bushing is formed in a ring shape, is fixedly connected to the bus bar, and includes a bushing body installed on the outside of the capacitor terminal, and a spring member formed in a spring shape, is installed inside the bushing body, and has an inner circumference fitted and fixed to the outer circumference of the capacitor terminal.

[0013] On the inner surface of the above bushing body, a spring mounting groove formed in a ring shape and recessed to a predetermined depth is further provided, and the spring member is fixedly connected to the inside of the spring mounting groove.

[0014] In the center of the above bushing body, a terminal through hole is further formed penetrating forward and backward, and through which the capacitor terminal is installed.

[0015] The above busbar is formed in a flat shape and includes a power module busbar connected to the power module section, and a capacitor busbar bent in a direction perpendicular to the power module busbar and connected to the capacitor terminal.

[0016] The above busbar is characterized by being composed of multiple layers of thin plate-shaped copper and insulation.

[0017] The DC capacitor fixing structure of the sub-module according to the present invention has the following effects.

[0018] The present invention has the advantage that the bus bar and capacitor terminal can be easily attached and detached by installing a spring member inside the bushing body and fitting it into the outer surface of the capacitor terminal, so that the assembly and disassembly time can be shortened during inspection and repair work on the sub-module, and work efficiency can be improved.

[0019] In addition, since the spring member is pressed and tightly fixed to the outer surface of the capacitor terminal, there is an advantage in that the current-conducting performance of the bus bar and capacitor terminal can be improved compared to the existing screw fixing method.

[0020] Figure 1 is a perspective view showing the configuration of a preferred embodiment of an ultra-high voltage direct current transmission system.

[0021] Figure 2 is a perspective view showing the configuration of a preferred embodiment of a submodule according to the present invention.

[0022] Fig. 3 is a perspective view showing a state in which a DC capacitor unit is coupled to a bus bar according to the present invention.

[0023] Figure 4 is an exploded perspective view showing a state in which the bus bar and DC capacitor portion constituting an embodiment of the present invention are separated.

[0024] Figure 5 is a drawing showing the configuration of a spring bushing constituting an embodiment of the present invention.

[0025] Fig. 6 is a cross-sectional view showing a state in which a spring bushing is coupled to a capacitor terminal constituting an embodiment of the present invention.

[0026] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. When designating components in each drawing, it should be noted that, where possible, identical components will be given the same reference numerals, even if they appear in different drawings. Furthermore, when describing embodiments of the present invention, if a detailed description of a related known structure or function is deemed to hinder understanding of the embodiments of the present invention, such detailed description will be omitted.

[0027] Additionally, terms such as first, second, A, B, (a), (b), etc. may be used to describe components of embodiments of the present invention. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms. When it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but another component may also be "connected," "coupled," or "connected" between each component.

[0028] Hereinafter, the configuration of the DC capacitor fixing structure of the sub-module of the embodiment of the present invention will be described with reference to the attached drawings.

[0029] As shown in these drawings, the DC capacitor fixing structure of the sub-module according to the present invention is composed of a power module section (20) including a switching element, a DC capacitor section (40) connected to the power module section (20), storing energy and maintaining a certain level of voltage, a capacitor terminal (44) protrudingly formed on one surface of the DC capacitor section (40) and connected to the power module section (20) to supply power, a bus bar (30) having one side connected to the power module section and the other side connected to the DC capacitor section (40), and a spring bushing (50) fixedly connected to the bus bar (30) and detachably installed to the capacitor terminal (44) to fix and release the bus bar (30) and the capacitor terminal (44).

[0030] First, the HVDC system will be described with reference to Fig. 1. In the HVDC system, a plurality of sub-modules (10) are installed in a row on a frame (F). The HVDC system is a system that converts AC power produced at a power plant into DC power, transmits it, and then reconverts it into AC power at a receiving point to supply power.

[0031] Fig. 2 is a perspective view showing the configuration of a preferred embodiment of a sub-module according to the present invention. The sub-module (10) of this embodiment is largely composed of a power module section (20) and a DC capacitor section (40).

[0032] The above power module part (20) is largely composed of a power housing (22) and an internal space (24). As shown in Fig. 2, the power housing (22) is formed in a roughly hollow hexahedral shape, and has a number of components installed inside, and serves to form the exterior.

[0033] An internal space (24) is formed inside the power housing (22). The internal space (24) is a hollow portion of the power housing (22), and is a portion where switching elements such as IGBTs, SMPSs, and controllers are installed together with various power semiconductors and various boards.

[0034] FIG. 3 and FIG. 4 are perspective views showing a state in which a DC capacitor unit is coupled to a bus bar according to the present invention, and FIG. 4 is an exploded perspective view showing a state in which a bus bar is separated from a DC capacitor unit constituting an embodiment of the present invention.

[0035] Referring to FIGS. 3 and 4, the bus bar (30) installed inside the power module (20) will be described in detail.

[0036] A bus bar (30) is installed inside the power housing (22). The bus bar (30) is composed of a power module bus bar (32) and a capacitor bus bar (34). The power module bus bar (32) is formed in a flat plate shape as shown in FIG. 3 and is installed inside the power housing (22). A switching element and various power semiconductors can be installed on the front or rear of the power module bus bar (32), and the power module bus bar (32) serves to supply power to the switching element and various power semiconductors.

[0037] The capacitor bus bar (34) is formed at the end of the power module bus bar (32). The capacitor bus bar (34) is formed by bending in a direction perpendicular to the end of the power module bus bar (32). The capacitor bus bar (34) can be formed integrally with the power module bus bar (32). As shown in FIG. 3, the capacitor bus bar (34) is connected to a DC capacitor section (40) to be described later and serves to transmit power to the power module bus bar (32).

[0038] In addition, the bus bar (30) may be formed into a structure in which thin plates of copper and insulating material are formed in multiple layers. The bus bar (30) is a portion where electrical connection and current flow are established between the switching element and various power semiconductors installed inside the power module portion (20) and the DC capacitor portion (40).

[0039] A power module connection hole (36) is formed on the side of the power module bus bar (32). The power module connection hole (36) is formed to penetrate the side of the power module bus bar (32) in the front and rear directions. A plurality of the power module connection holes (36) may be formed in a single row on the side of the power module bus bar (32). The power module connection hole (36) is a portion where switching elements and various power semiconductors are installed and conduct electricity.

[0040] A capacitor connection hole (38) is formed on the front surface of the capacitor bus bar (34). The capacitor connection hole (38) is formed to penetrate the front surface of the capacitor bus bar (34) in a front-to-back manner. A plurality of capacitor connection holes (38) may be formed in a single row on the front surface of the capacitor bus bar (34). A spring bushing (50), which will be described later, is fixedly connected to the capacitor connection hole (38) to fix the bus bar (30), and a capacitor terminal (44), which will be described later, is inserted through the hole to fix and release the capacitor.

[0041] In addition, a spring bushing (50) to be described later is fixedly connected to the capacitor connection hole (38), and a capacitor terminal (44) to be described later is connected through a through hole, so that electrical connection and current flow can be achieved between the capacitor bus bar (34) and the DC capacitor section (40) to be described later.

[0042] A DC capacitor unit (40) is installed at the rear of the power module unit (20). The DC capacitor unit (40) may be composed of a capacitor housing (42) and a capacitor element (not shown). The capacitor housing (42) has a roughly hollow hexahedral shape, and a number of components are installed inside. The capacitor housing (42) serves to protect the components installed inside and form the exterior.

[0043] A capacitor element is installed inside the above capacitor housing (42). The capacitor element stores energy (electricity) input to the sub-module (10), and this energy can be used as a power source for driving various devices installed in the sub-module (10) and can be supplied as reactive power to the power system.

[0044] A capacitor terminal (44) is installed on the front surface of the capacitor housing (42). The capacitor terminal (44) is a general electrode terminal, and a detailed description thereof will be omitted. A plurality of the capacitor terminals (44) are formed to protrude in a row on the front surface of the capacitor housing (42). The capacitor terminals (44) can be electrically connected to the capacitor element, and serve to supply power to the power module section (20) of the DC capacitor section (40).

[0045] Hereinafter, the spring bushing constituting the embodiment of the present invention will be described in detail with reference to FIGS. 5 and 6. The spring bushing (50) is fixedly connected to the capacitor connection hole (38).

[0046] The above spring bushing (50) is composed of a bushing body (52), a spring mounting groove (56), and a spring member (58).

[0047] The above bushing body (52) is formed in a ring shape and is fixedly connected to the capacitor connection hole (38) through a forced press-fit method. The bushing body (52) is connected to the outside of the capacitor terminal (44), and its side is in close contact with one surface of the bus bar (30). A spring member (58), which will be described later, is installed inside the bushing body (52) so as to be electrically connected to the capacitor terminal (44), and is a part where electrical connection and current flow are established between the capacitor terminal (44) and the capacitor bus bar (34).

[0048] A terminal through hole (54) is formed on the front surface of the above bushing body (52). The terminal through hole (54) has a diameter larger than the outer diameter of the capacitor terminal (44) described below, and is formed to penetrate forward and backward through the front surface of the bushing body (52). The inside of the terminal through hole (54) is a portion through which the capacitor terminal (44) is installed to penetrate forward and backward.

[0049] In addition, a spring mounting groove (56) is formed on the inner surface of the bushing body (52). The spring mounting groove (56) may have a square or circular cross-section, and is formed by being recessed to a predetermined depth along the inner surface of the bushing body (52). The spring mounting groove (56) is a portion where a spring member (58), which will be described later, is installed and fixed, as shown in FIG. 5.

[0050] A busbar mounting portion (57) is formed on the circumference of the bushing body (52). The busbar mounting portion (57) is formed in a ring shape at the rear end of the bushing body (52). The busbar mounting portion (57) is a portion that is forcibly pressed into the capacitor connection hole (38). The busbar mounting portion (57) is joined to the capacitor connection hole (38) through a forcibly pressed method, thereby serving to fix the bushing body (52) to the busbar (30).

[0051] A spring member (58) is installed inside the spring mounting groove (56). The spring member (58) is a general spring, and a detailed description thereof will be omitted. The spring member (58) is formed in an elastically deformable ring shape. A portion of the spring member (58) is fixed inside the spring mounting groove (56), and the remaining portion is installed so as to be pressed against and in close contact with the outer surface of the capacitor terminal (44) along the circumference. The spring member (58) is installed in the spring mounting groove (56) so as to be pressed against and in close contact with the outer surface of the capacitor terminal (44), thereby being able to conduct current with the capacitor terminal (44) and playing a role of firmly fixing the bushing body (52) to the capacitor terminal (44).

[0052] That is, the spring bushing (50) is detachably connected to the capacitor terminal (44) while being fixedly connected to the bus bar (30), thereby serving to fix and release the bus bar (30) and the capacitor terminal (44).

[0053] In addition, since a spring member (58) is installed inside the bushing body (52) and is fitted into the outer surface of the capacitor terminal (44), the bus bar (30) and the capacitor terminal (44) can be easily attached and detached, so that the assembly and disassembly time can be shortened and work efficiency can be improved when inspecting and repairing the sub-module (10).

[0054] In addition, as the spring member (58) is pressed and tightly fixed to the outer surface of the capacitor terminal (44), the current-conducting performance of the bus bar (30) and the capacitor terminal (44) can be improved compared to the existing screw fixing method.

[0055] Although all components constituting the embodiments of the present invention have been described above as being combined or operating in combination, the present invention is not necessarily limited to these embodiments. That is, within the scope of the purpose of the present invention, all components may be selectively combined and operated one or more times. In addition, terms such as "include," "comprise," or "have" described above, unless specifically stated to the contrary, mean that the corresponding component may be inherent, and therefore should be interpreted as including other components rather than excluding other components. All terms, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the art to which the present invention pertains, unless otherwise defined. Commonly used terms, such as terms defined in a dictionary, should be interpreted as being consistent with the contextual meaning of the related technology, and shall not be interpreted in an ideal or excessively formal sense, unless explicitly defined in the present invention.

[0056] The above description is merely an illustrative illustration of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate, rather than limit, the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. A power module section including a switching element; A DC capacitor section connected to the above power module section, storing energy and maintaining a certain level of voltage; A capacitor terminal protrudingly formed on one surface of the DC capacitor section and connected to the power module section to supply power; A bus bar having one side connected to the power module section and the other side connected to the DC capacitor section; A DC capacitor fixing structure of a sub-module including a spring bushing that is fixedly connected to the bus bar and detachably installed on the capacitor terminal to fix and release the bus bar and the capacitor terminal.

2. In the first paragraph, the spring bushing, A bushing body having a ring shape, fixedly connected to the bus bar, and installed on the outside of the capacitor terminal; A DC capacitor fixing structure of a sub-module including a spring member having a spring shape, installed inside the bushing body, and having an inner surface fitted and fixed to the outer surface of the capacitor terminal.

3. In the second paragraph, on the inner surface of the bushing body, It is formed by sinking to a predetermined depth and further has a spring-mounted groove formed in a ring shape; A DC capacitor fixing structure of a sub-module characterized in that the spring member is fixedly connected inside the spring mounting groove.

4. In the third paragraph, in the center of the bushing body, A DC capacitor fixing structure of a sub-module characterized by having a terminal through-hole formed in the front and rear and through which the capacitor terminal is installed.

5. In the first paragraph, the bus bar, A power module bus bar formed in the form of a flat plate and connected to the power module section; A DC capacitor fixing structure of a sub-module including a capacitor bus bar formed by bending in a direction perpendicular to the power module bus bar and coupled to the capacitor terminal.

6. In the fifth paragraph, the bus bar, A DC capacitor fixing structure of a sub-module characterized by being composed of multiple layers of thin plate-shaped copper and insulating material.

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