Voltage supply device and inverter device equipped therewith

Abstract

If a cylindrical core is provided for each high-potential and low-potential wiring connected to each converter, the voltage supply device will become larger. [Solution] The voltage supply device 100A supplies voltage with a waveform corresponding to the drive of switching elements 6A to 6C from switching elements 6A to 6C connected in series. High-potential side wiring 51A to 51C and low-potential side wiring 52A to 52C are connected to each converter 2A to 2C from the power supply 9A. The common mode choke coil 10 is provided with at least a cylindrical core 20A having through holes 22 formed therein. Multiple high-potential side wirings 51A to 51C and multiple low-potential side wirings 52A to 52C connected to each converter are inserted through the through holes.

Description

TECHNICAL FIELD

[0001] The present invention relates to a voltage supply device and an inverter device including the same.

BACKGROUND ART

[0002] As a technique of this type, for example, Patent Document 1 proposes a common mode choke coil in which a first winding and a second winding are wound around a cylindrical core (iron core). The first winding and the second winding are electromagnetically coupled by the cylindrical core. When the first winding and the second winding are, for example, a high-potential-side wiring and a low-potential-side wiring connected to a power supply, one end of these wirings is connected to the power supply, and the other end is connected to a converter. Thereby, the common mode current can be reduced by the common mode choke coil.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0003]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] However, for example, when a plurality of such converters are provided in the voltage supply device, a cylindrical core is provided for each of the high-potential-side wiring and the low-potential-side wiring connected to each converter, which results in an increase in the size of the voltage supply device.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to provide a voltage supply device capable of suppressing common mode current and achieving miniaturization of the voltage supply device even when a plurality of converters are provided.

MEANS FOR SOLVING THE PROBLEMS

[0006] In view of the above problems, the voltage supply device according to the present invention comprises a plurality of switching elements connected in series, a plurality of drive circuits for driving each of the plurality of switching elements, a plurality of converters for supplying voltage to each of the plurality of drive circuits, and a common mode choke coil provided between each of the plurality of converters and a power supply that supplies voltage to each of the converters, and is a voltage supply device that supplies a voltage with a waveform corresponding to the driving of the switching elements from the series-connected switching elements. In the voltage supply device, each of the converters is connected to the power supply by a high-potential side wiring and a low-potential side wiring, and the common mode choke coil has a cylindrical core with through holes formed therein, through which a plurality of the high-potential side wiring and a plurality of the low-potential side wiring connected to each of the converters are inserted.

[0007] According to the voltage supply device of the present invention, common-mode current can be reduced by a common-mode choke coil. Furthermore, since multiple high-potential-side wirings and multiple low-potential-side wirings are inserted through a through-hole in the cylindrical core of a single common-mode choke coil, the voltage supply device can be made more compact.

[0008] In a more preferred embodiment, the high-potential side wiring and the low-potential side wiring connected to each of the converters are twisted together in pairs.

[0009] According to this embodiment, among the multiple high-potential wirings and multiple low-potential wirings, the corresponding high-potential wirings and low-potential wirings are twisted together in pairs, thereby reducing noise generated in the high-potential wirings and low-potential wirings.

[0010] The present invention also discloses an inverter device equipped with a pair of the above-described voltage supply devices. The inverter device according to the present invention is an inverter device that converts a DC voltage from a DC power supply connected to the pair of voltage supply devices into a pulse voltage and outputs it from an output terminal. The pair of voltage supply devices are connected to the output terminal with an output node in between, and the inverter device includes a control device that generates a pulse voltage from the DC voltage of the DC power supply by alternately driving and controlling a plurality of the drive circuits of one of the pair of voltage supply devices and a plurality of the drive circuits of the other voltage supply device. The common mode choke coil has a pair of cylindrical cores, and of the pair of cylindrical cores, a plurality of the high-potential side wirings and a plurality of the low-potential side wirings of the one voltage supply device are inserted into one cylindrical core, and a plurality of the high-potential side wirings and a plurality of the low-potential side wirings of the other voltage supply device are inserted into the other cylindrical core.

[0011] According to the inverter device of the present invention, a control device can generate a pulse voltage from the DC voltage of a DC power supply by alternately controlling the drive circuits of multiple drive circuits of one voltage supply device and multiple drive circuits of the other voltage supply device. In this case, the common mode current can be suppressed by a common mode choke coil.

[0012] Furthermore, multiple high-potential and low-potential wirings of each of the pair of voltage supply devices are inserted through each of the pair of cylindrical cores that constitute the common-mode choke coil. This allows common-mode current to be suppressed with a single common-mode choke coil. To achieve this effect, only one common-mode choke coil is needed in the inverter device, which allows for a more compact inverter device.

[0013] In a more preferred embodiment, the pair of cylindrical cores are arranged side by side, and the configuration further includes a metal block having a cylindrical housing space for housing each of the side by side, and a heat dissipation sheet disposed between the inner circumferential surface and the outer circumferential surface so as to contact the inner circumferential surface and the outer circumferential surface of the cylindrical core, which cover the outer circumferential surface of each of the cylindrical cores and form the housing space of the block.

[0014] In this embodiment, multiple high-potential wirings and multiple low-potential wirings are inserted through holes in each cylindrical core when a pair of cylindrical cores are arranged side by side. As a result, the multiple high-potential wirings and multiple low-potential wirings are not arranged on the outer circumferential surfaces of the pair of cylindrical cores. Therefore, the heat dissipation sheet can be placed in close contact with the outer circumferential surface of each cylindrical core, without any gaps being formed by wiring or the like along the outer circumferential surface of each cylindrical core, thereby covering the outer circumferential surface of the cylindrical core with the heat dissipation sheet. This heat dissipation sheet is placed between the inner circumferential surface that forms the housing space of the block and the outer circumferential surface of the cylindrical core, and is in contact with both the inner and outer circumferential surfaces. As a result, the heat generated from the cylindrical core by the current flowing through the multiple high-potential wirings and multiple low-potential wirings can be efficiently dissipated from the heat dissipation sheet placed on the outer circumferential surface of the cylindrical core to the metal block.

[0015] In a more preferred embodiment, the block is electrically connected to ground, and the high-potential side wiring and the low-potential side wiring are wirings in which conductive wires are coated with an insulating resin material.

[0016] In this embodiment, the heat dissipation sheet electrically insulates the cylindrical core and the metal block. Furthermore, since the cylindrical core and the metal block each act as electrodes and the heat dissipation sheet acts as a dielectric, the portion from the cylindrical core to the metal block functions as a first capacitor. Additionally, since each high-potential side wiring and each low-potential side wiring acts as electrodes, and the resin material covering each high-potential side wiring and each low-potential side wiring, as well as the space between each high-potential side wiring, each low-potential side wiring, and the cylindrical core, acts as a dielectric, the portion from each high-potential side wiring and each low-potential side wiring to the cylindrical core functions as a second capacitor.

[0017] At this time, the cylindrical core is at a floating potential. That is, a first capacitor and a second capacitor are connected in series between the metal block, each high-potential-side wiring, and each low-potential-side wiring. The first capacitor and the second capacitor formed in this way function like the Y capacitor of a common mode choke coil, so that common mode current can be suppressed. [Advantageous Effects of the Invention]

[0018] According to the present invention, even when a plurality of converters are provided, common mode current can be suppressed, and the voltage supply device can be reduced in size. [Brief Description of the Drawings]

[0019] [Figure 1] This is a block diagram of an inverter device provided with a voltage supply device according to an embodiment of the present invention. [Figure 2A] This is a block diagram of the voltage supply device on one side shown in FIG. 1. [Figure 2B] This is a block diagram of the voltage supply device on the other side shown in FIG. 1. [Figure 3] This is a schematic perspective view of the common mode choke coil of the inverter device shown in FIG. 2A and FIG. 2B. [Figure 4] This is an exploded perspective view of a portion of the common mode choke coil shown in FIG. 3 excluding the high-potential-side wiring and the low-potential-side wiring. [Figure 5] This is a schematic cross-sectional view taken along the line A-A of the common mode choke coil shown in FIG. 3, viewed in the direction of the arrows. [Figure 6] (a) is a cross-sectional view taken along the line B-B of the common mode choke coil shown in FIG. 5, viewed in the direction of the arrows, and (b) is a cross-sectional view taken along the line C-C of the common mode choke coil shown in FIG. 5, viewed in the direction of the arrows. [Figure 7] (a) is a cross-sectional view taken along the line D-D of the common mode choke coil shown in FIG. 6, viewed in the direction of the arrows, and (b) is a cross-sectional view, taken along the line D-D according to a modified example of the common mode choke coil shown in FIG. 6, viewed in the direction of the arrows. [Figure 8] (a) is a diagram for explaining the potential state of the common mode choke coil shown in FIG. 2, and (b) is a block diagram for explaining the function of the common mode choke coil in the inverter device shown in FIG. 2. [Mode for Carrying Out the Invention]

[0020] Hereinafter, a voltage supply device 100A (100B) according to the present invention and an inverter device 1 including the same will be described with reference to FIG. 1 to FIG. 8. In the present embodiment, the inverter device 1 is used, for example, as a pulse power supply device used when performing plasma processing.

[0021] As shown in FIG. 1, the inverter device 1 includes a pair of voltage supply devices 100A and 100B that supply a pulse voltage to an output terminal 120 described later, and a control device 130 that controls gate drive circuits 5A to 5C and 5D to 5F (see FIG. 2A and FIG. 2B) of the voltage supply devices 100A and 100B described later. As shown in FIG. 1 and FIG. 2A, of the pair of voltage supply devices 100A and 100B, one voltage supply device 100A includes a plurality of (for example, three) switching elements 6A to 6C connected in series. Similarly, as shown in FIG. 1 and FIG. 2B, the other voltage supply device 100B also includes a plurality of switching elements 6D to 6F connected in series. These switching elements 6A to 6F are semiconductor switching elements of the same type, such as high-voltage FETs (field effect transistors). In FIG. 2A and FIG. 2B, each of the switching elements 6A to 6F is illustrated as a single element, but a plurality of (for example, two) switching elements may be connected in parallel.

[0022] In this embodiment, multiple switching elements 6A to 6C of one voltage supply device 100A and multiple switching elements 6D to 6F of the other voltage supply device 100B are connected to the output terminal 120 via the output node 110. A high-voltage DC power supply 90, for example, 12kV, is connected to the pair of voltage supply devices 100A and 100B. As will be described later, the DC voltage of the DC power supply 90 is converted into a pulse voltage by the pair of voltage supply devices 100A and 100B and the control device 130 that controls them, and output from the output terminal 120.

[0023] In this embodiment, both the pair of voltage supply devices 100A and 100B have the same number (specifically, three) of switching elements 6A-6C and 6D-6F, and the configuration of each switching element and the gate drive circuit that operates the switching elements is the same. Therefore, below, one of the voltage supply devices 100A shown in Figure 2A will be described in detail, and the other voltage supply device 100B shown in Figure 2B will only have its reference numeral at the end of Figure 2B changed, and its detailed description will be omitted.

[0024] As shown in Figure 2A, in this embodiment, one voltage supply device 100A includes, in addition to switching elements 6A to 6C, a number of gate drive circuits 5A to 5C, converters 2A to 2C, etc., corresponding to the number of switching elements 6A to 6C. One voltage supply device 100A is equipped with a power supply (DC power supply) 9A. Furthermore, one voltage supply device 100A is equipped with a common mode choke coil 10 common to the other voltage supply device 100B (see Figure 3). In this embodiment, as shown in Figure 2B, the other voltage supply device 100B is equipped with a power supply 9B, but power supplies 9A and 9B may be composed of a single power supply. Each of the switching elements 6A to 6C is driven by the corresponding gate drive circuits 5A to 5C. Each of the gate drive circuits 5A to 5C is controlled by the control device 130 shown in Figure 1.

[0025] Specifically, a control signal from the control device 130 is converted into an optical signal (pulse signal) by the PWM optical transmission units 3A to 3C, and then converted into a voltage signal (pulse signal) by the optical reception units 4A to 4C. This voltage signal (pulse signal) is input to the gate drive circuits 5A to 5C. With this input voltage signal (pulse signal), each gate drive circuit 5A to 5C can drive its corresponding switching element 6A to 6C almost simultaneously. The optical signal from the PWM optical transmission units 3A to 3C to the optical reception units 4A to 4C is transmitted via an optical fiber. In this embodiment, the control of each gate drive circuit 5A to 5C is performed by converting the control signal from the control device 130 into an optical signal. However, the control may also be performed using an electrical signal from the control device 130, and the control method is not limited as long as the control device 130 can perform the control.

[0026] In this embodiment, the potential at the high-potential terminal of power supply 9A is, for example, 24V, and the potential at the low-potential terminal of the DC power supply is, for example, ground potential. That is, the DC power supply outputs a DC voltage with a potential difference of 24V. Power supply 9A is connected to each of the three converters 2A to 2C. High-potential wiring 51A to 51C and low-potential wiring 52A to 52C are connected to each of the converters 2A to 2C from power supply 9A. In this embodiment, converters 2A to 2C are isolated DC-DC converters. Each converter 2A to 2C has a built-in transformer (not shown), which isolates the primary side (input side) from the secondary side (output side). In this embodiment, the step-up ratio of the transformer is 1, but is not limited to this.

[0027] The voltage from the 9A power supply is transmitted through the transformers of multiple converters 2A to 2C. The transmitted voltage is input as the gate drive voltage to the corresponding gate drive circuits 5A to 5C. This gate drive voltage is the voltage supplied by the gate drive circuits 5A to 5C between the gate and source of the switching elements 6A to 6C.

[0028] In this embodiment, since the boost ratio of the transformer is 1, the potential difference between the high-potential and low-potential sides of the primary side (input side) of the transformer and the potential difference between the high-potential and low-potential sides of the secondary side (output side) are the same (for example, 24V). However, since the low-potential sides of the secondary side (output side) of the transformers of the multiple converters 2A to 2C are connected to the sources of the switching elements 6A to 6C via the gate drive circuits 5A to 5C, the potentials of the primary side (input side) and secondary side (output side) of each transformer are different.

[0029] Meanwhile, the control signals from the control device 130 shown in Figure 1 cause the PWM optical transmitters 3A to 3C to transmit optical signals (pulse signals) to the optical receivers 4A to 4C via optical fibers. The optical receivers 4A to 4C convert the optical signals (pulse signals) into voltage signals (pulse signals). The gate drive circuits 5A to 5C switch the gate drive voltage that turns the switching elements 6A to 6C on and off using the voltage signals (pulse signals) output from the optical receivers 4A to 4C. As a result, the voltage supply device 100A can supply a pulse waveform voltage corresponding to the drive of the switching elements 6A to 6C from the series-connected switching elements 6A to 6C.

[0030] The control device 130 generates a pulse voltage from the DC voltage of the DC power supply 90 by alternately driving and controlling the multiple gate drive circuits 5A to 5C of one voltage supply device 100A shown in Figure 2A and the multiple gate drive circuits 5D to 5F of the other voltage supply device 100B shown in Figure 2B. Specifically, when the multiple gate drive circuits 5A to 5C of one voltage supply device 100A turn on the switching elements 6A to 6C, the multiple gate drive circuits 5D to 5F of the other voltage supply device 100B turn the switching elements 6D to 6F off. When the multiple gate drive circuits 5A to 5C of one voltage supply device 100A turn on the switching elements 6D to 6F, the multiple gate drive circuits 5D to 5F of the other voltage supply device 100B turn the switching elements 6D to 6F on. By repeating this process, a pulse voltage is output from the output terminal 120. In this case, the frequency of the generated pulse voltage waveform is approximately several hundred kHz, but it may be various frequencies, such as several tens of kHz or approximately 1 MHz.

[0031] In this embodiment, a positive voltage, such as 12kV, is applied to the inverter device 1. That is, the potential difference between the potential of the high-potential terminal and the potential of the low-potential terminal of the DC power supply 90 is, for example, 12kV, and the low-potential terminal of the DC power supply 90 is connected to ground potential, such as 0kV. Therefore, the potential of the high-potential terminal becomes 12kV, and thus the output voltage of the DC power supply 90 becomes +12kV. As a result, pulsed voltages of 12kV and 0kV are output alternately from the output terminal 120.

[0032] A negative voltage, such as -12kV, may be applied to the inverter device 1. That is, the high-potential terminal of the DC power supply 90 may be connected to a ground potential such as 0kV, and the potential of the low-potential terminal may be set to -12kV, so that the output voltage of the DC power supply 90 is -12kV. In this case, pulsed voltages of -12kV and 0kV will be output alternately from the output terminal 120.

[0033] As shown in Figures 2A, 2B, and 3, the common mode choke coil 10 is positioned between the power supply 9A of one voltage supply device 100A and the multiple converters 2A to 2C, and between the power supply 9B of the other voltage supply device 100B and the multiple converters 2D to 2F. The common mode choke coil 10 functions as a filter to cut noise from the voltage waveforms input from converters 2A to 2C and 2D to 2F to power supplies 9A and 9B.

[0034] In other words, a leakage current called common-mode current flows from each converter 2A to 2C (2D to 2F) towards the power supply 9A (9B) in accordance with the switching period of the multiple switching elements 6A to 6C (6D to 6F) of each voltage supply device 100A (100B), but the common-mode current can be reduced by the common-mode choke coil 10.

[0035] As shown in Figures 3 to 7, the common mode choke coil 10 comprises a pair of cylindrical cores 20A and 20B, and high-potential side wiring 51A to 51F and low-potential side wiring 52A to 52F inserted through the pair of cylindrical cores 20A and 20B. Specifically, as shown in Figure 3, of the pair of cylindrical cores 20A and 20B, a plurality of high-potential side wiring 51A to 51C and a plurality of low-potential side wiring 52A to 52C of one voltage supply device 100A are inserted through one cylindrical core 20A. A plurality of high-potential side wiring 51D to 51F and a plurality of low-potential side wiring 52D to 52F of the other voltage supply device 100B are inserted through the other cylindrical core 20B. The pair of cylindrical cores 20A and 20B, together with a heat dissipation sheet 40 (described later), are housed in a metal block 30 made of aluminum or copper.

[0036] As shown in Figure 4, the cylindrical core 20A (20B) is a toroidal core, which is a molded body (e.g., a compacted magnetic core) formed from a soft magnetic material such as ferrite. The cylindrical core 20A (20B) has cylindrical through holes 22 through which the high-potential side wiring 51A~51C (51D~51F) and the low-potential side wiring 52A~52C (52D~52F) are inserted. In this embodiment, each cylindrical core 20A (20B) is composed of a divided core 21 which is divided into multiple (e.g., three) sections in a direction intersecting the axial direction, but it may also be composed as a single core.

[0037] As shown in Figure 3, the two corresponding wires of the high-potential side wiring 51A~51F and the low-potential side wiring 52A~52F are twisted together in pairs, forming a so-called twisted-pair cable. As shown in Figures 3 and 5, these high-potential side wiring 51A~51C (51D~51F) and low-potential side wiring 52A~52C (52D~52F) are inserted through the through-holes 22 of each cylindrical core 20A (20B) with a pair of cylindrical cores 20A and 20B arranged side by side.

[0038] In this embodiment, the high-potential wiring 51A-51F and the low-potential wiring 52A-52F are wirings in which a conductive wire (not shown) is covered with an insulating resin material. In this embodiment, the wire is a copper wire, and the resin material covering the wire is an insulating material, and examples of insulating resins include fluororesin, polyvinyl chloride, and nylon. The resin material is not particularly limited as long as it has the necessary pressure resistance (for example, pressure resistance of several hundred volts) for the high-potential wiring 51A-51F and the low-potential wiring 52A-52F and can ensure the flexibility (flexibility) of the high-potential wiring 51A-51F and the low-potential wiring 52A-52F. Since the high-potential wiring 51A-51F and the low-potential wiring 52A-52F are made of wires coated with resin material, it is possible to prevent the high-potential wiring 51A-51F and the low-potential wiring 52A-52F from coming into direct contact with block 30.

[0039] The block 30 has a tetrahedral (or rectangular parallelepiped in this embodiment) external shape, and has a cylindrical housing space S (see, for example, Figures 4 and 5) that accommodates each of the parallel cylindrical cores 20A (20B). The housing space S is a space that penetrates the block 30, and circular opening edges 34 (see, for example, Figure 4) corresponding to the shape of the housing space S are formed on the end faces 30a on both sides of the block 30.

[0040] In this embodiment, the block 30 is composed of divided bodies 31 and 32, which divide the cylindrical storage space S in half along the axial direction. As a result, each of the divided bodies 31 and 32 has a semicircular inner surface 35 that forms the storage space S.

[0041] As shown in Figure 3, the divided parts 31 and 32 are connected to each other via fastening members 71, such as long screws, with their respective divided surfaces 38 and 39 facing each other. Specifically, each of the divided parts 31 and 32 has multiple mounting holes 36 (for example, two on each side, a total of four) that are screwed into the fastening members 71, sandwiching a pair of inner circumferential surfaces 35, 35. The divided parts 31 and 32 are connected to each other by screwing the fastening members 71 into each mounting hole 36 and tightening the fastening members 71.

[0042] As shown in Figures 4 and 5, four insulating guide members (guide posts) 8 are attached to guide the high-potential wiring 51A to 51F and the low-potential wiring 52A to 52F so that they do not come into contact with the end face 30a of the block 30.

[0043] Each guide member 8 is made of an insulating resin material and is positioned opposite the end faces of the cylindrical cores 20A and 20B. The guide members 8 are attached to the casing (not shown) of the inverter device 1. Specifically, each guide member 8 comprises a base portion 83 fixed to the casing, a support column portion 82 erected from the base portion 83, and a guide portion 81 connected to the tip of the support column portion 82, with a guide hole 84 formed therein.

[0044] Specifically, guide holes 84, 84 of a pair of guide members 8, 8 are positioned opposite the through-hole 22 of the cylindrical core 20A, sandwiching the cylindrical core 20A, and the high-potential wiring 51A~51C and low-potential wiring 52A~52C of one of the voltage supply devices 100A are inserted through the guide holes 84, 84. Similarly, guide holes 84, 84 of a pair of guide members 8, 8 are positioned opposite the through-hole 22 of the cylindrical core 20B, sandwiching the cylindrical core 20B, and the high-potential wiring 51D~51F and low-potential wiring 52D~52F of the other voltage supply device 100B are inserted through the guide holes 84, 84. As a result, the high-potential wiring 51A~51F and low-potential wiring 52A~52F are supported by the pair of guide members 8, 8 positioned on both sides of the block 30.

[0045] As a result, contact between the high-potential wiring 51A-51F and the low-potential wiring 52A-52F and the end face 30a of the block 30 can be avoided. In this embodiment, a guide member 8 is provided to guide the high-potential wiring 51A-51F and the low-potential wiring 52A-52F, but for example, instead of the guide member 8, a clamping mechanism that holds the high-potential wiring 51A-51F and the low-potential wiring 52A-52F in a predetermined position may be provided.

[0046] Preferably, the dividing surfaces 38 and 39 of the divided bodies 31 and 32 (see, for example, Figures 4 and 6) are coated with a highly thermally conductive grease, such as a silicone-based grease, and metal or ceramic compound particles may be dispersed in this grease. However, when the divided bodies 31 and 32 are connected by fastening members 71 with a heat dissipation sheet 40 sandwiched between them, gaps may be formed between the dividing surfaces 38 and 39. Since these gaps can be filled with grease, it is possible to suppress the impairment of thermal conductivity between the divided bodies 31 and 32 caused by these gaps. Furthermore, if the grease is electrically conductive, the entire block 30 can be set to the potential of ground by electrically connecting either one of the divided bodies 31 or 32 to ground.

[0047] Through holes 37 are formed at the four corners of the block 30, penetrating the block 30. Fixing devices (not shown) can be inserted through these through holes 37 to fix the block 30 to a heat sink (not shown) or the like. The block 30 is a rectangular parallelepiped, and the surface of the block 30 that contacts the heat sink (the surface 30t on the side into which the fastening member 71 is inserted and the opposite surface 30b) are flat, so the heat dissipated from the block 30 can be efficiently transferred to the heat sink.

[0048] The heat dissipation sheet 40 is a sheet material that is heat-dissipating and elastically deformable, and the heat dissipation sheet 40 is, for example, a rubber sheet. In this embodiment, the heat dissipation sheet 40 is insulating. The thermal conductivity of the heat dissipation sheet 40 is preferably in the range of 1.0 W / mK to 3.0 W / mK, and more preferably in the range of 1.8 W / mK to 2.3 W / mK. The dielectric breakdown voltage of the heat dissipation sheet 40 is preferably 1 kV or more in the thickness direction, and this value can be adjusted by the thickness of the heat dissipation sheet 40. In this embodiment, the dielectric breakdown voltage of the heat dissipation sheet 40 is about 20 kV.

[0049] Examples of materials for such a heat dissipation sheet 40 include insulating rubber materials such as silicone rubber. The heat dissipation sheet 40 covers the outer peripheral surface 23 of each cylindrical core 20A (20B) and is positioned between the inner peripheral surface 35 and the outer peripheral surface 23 so as to be in contact with the inner peripheral surface 35 that forms the housing space S of the block 30 and the outer peripheral surface 23 of the cylindrical core 20A (20B). In this embodiment, the heat dissipation sheet 40 consists of divided sheets 41 and 42 that are positioned on the inner peripheral surface 35 of the housing space formed in each of the divided bodies 31 and 32 that constitute the block 30. The heat dissipation sheet 40 is sandwiched between the divided bodies 31 and 32 in a compressed and deformed state by fastening the fastening member 71.

[0050] Specifically, in this embodiment, the outer diameter of the cylindrical core 20A (20B) covered with the heat dissipation sheet 40 is larger than the inner diameter of the housing space S. As a result, when the fastening member 71 is tightened, the divided parts 31 and 32 are attracted to each other, and the heat dissipation sheet 40 can be compressed and deformed so that it comes into close contact with the inner circumferential surface 35 that forms the housing space S and the outer circumferential surface 23 of the cylindrical core 20A (20B).

[0051] According to this embodiment, the high-potential wiring 51A to 51C and low-potential wiring 52A to 52C of one voltage supply device 100A are inserted through the through-hole 22 of the cylindrical core 20A, and the high-potential wiring 51D to 51F and low-potential wiring 52D to 52F of the other voltage supply device 100B are inserted through the through-hole 22 of the cylindrical core 20A.

[0052] As a result, the high-potential wiring 51A-51F and low-potential wiring 52A-52F are not arranged on the outer circumferential surfaces 23 of the pair of cylindrical cores 20A and 20B. Therefore, gaps caused by the high-potential wiring 51A-51C and low-potential wiring 52A-52C, etc., are suppressed along the outer circumferential surface 23 of each cylindrical core 20A (20B), and the heat dissipation sheet 40 can cover the outer circumferential surface 23 of each cylindrical core 20A (20B). This heat dissipation sheet 40 is placed between the inner circumferential surface 35 that forms the housing space S of the block 30 and the outer circumferential surface 23 of each cylindrical core 20A (20B), and is in contact with the inner circumferential surface 35 and the outer circumferential surface 23.

[0053] As a result, the heat generated from each of the pair of cylindrical cores 20A and 20B by the current flowing through the high-potential wiring 51A to 51F and the low-potential wiring 52A to 52F can be efficiently dissipated from the heat dissipation sheet 40 placed on the outer circumferential surfaces 23 of the cylindrical cores 20A and 20B to the metal block 30. In particular, in this embodiment, the heat dissipation sheet 40 is compressed and deformed by the fastening member 71 (specifically, by tightening the fastening member 71) and sandwiched between the divided bodies 31 and 32. As a result, the heat dissipation sheet 40 is in close contact with the inner circumferential surface 35 that forms the housing space S of the block and the respective outer circumferential surfaces 23 of the cylindrical cores 20A and 20B, so that the formation of a gap between the heat dissipation sheet 40 and the inner circumferential surface 35 and outer circumferential surface 23 can be suppressed.

[0054] As shown in Figure 4, the use of four guide members 8 makes it easier to avoid contact between the high-potential wiring 51A-51F and the low-potential wiring 52A-52F and the end face 30a of the block 30. As a result, even if the potential of the high-potential wiring 51A-51F and the low-potential wiring 52A-52F is set to a higher potential relative to the block 30, electrical insulation of the high-potential wiring 51A-51F and the low-potential wiring 52A-52F can be ensured.

[0055] Furthermore, as shown in the modified example in Figure 7(b), instead of using the guide member 8, the peripheral edge 41a of the heat dissipation sheet 40 may protrude from the end face 30a of the block 30. This prevents the high-potential wiring 51A~51C (51D~51F) and low-potential wiring 52A~52C (52D~52F) from coming into contact with the peripheral edge 41a, and prevents the high-potential wiring 51A~51C (51D~51F) and low-potential wiring 52A~52C (52D~52F) from coming into contact with the end face 30a of the block 30.

[0056] In this modified example, the block 30 does not have a guide member 8. However, if the high-potential wiring 51A~51C (51D~51F) and low-potential wiring 52A~52C (52D~52F) are routed in a way that makes it easy for them to come into contact with the end face 30a of the block 30, the guide member 8 shown in Figure 4 may be provided. Furthermore, the high-potential wiring 51A~51C (51D~51F) and low-potential wiring 52A~52C (52D~52F) may be secured with resin cable ties so as to cover them, or the high-potential wiring 51A~51C (51D~51F) and low-potential wiring 52A~52C (52D~52F) may be gripped with resin clamps attached to external equipment, etc.

[0057] Next, the effects of the voltage supply device 100A (100B) of this embodiment will be explained. Depending on the switching period of the multiple switching elements 6A~6C (6D~6F) of each voltage supply device 100A (100B), a leakage current called common-mode current is generated, and this common-mode current flows from each converter 2A~2C (2D~2F) to the power supply 9A (9B). In contrast, by configuring the voltage supply device 100A (100B) as in this embodiment, the common-mode current can be reduced.

[0058] For example, the 9A (9B) power supply has a built-in detection circuit to set the output voltage to a specified value (e.g., 24V). However, if common-mode current flows into this detection circuit, a malfunction may occur where the output voltage cannot be correctly controlled to the specified value. Therefore, by reducing the common-mode current according to this embodiment, the occurrence of such malfunctions can be suppressed.

[0059] Furthermore, since multiple high-potential wirings 51A~51C (51D~51F) and multiple low-potential wirings 52A~52C (52D~52F) are inserted through the through-holes 22 of the cylindrical core 20A (20B) of a single common-mode choke coil 10, the voltage supply devices 100A and 100B can be made more compact. This also allows for a more compact inverter device 1.

[0060] Furthermore, multiple high-potential wirings 51A~51C and multiple low-potential wirings 52A~52C of one voltage supply device 100A are inserted through the through-holes 22 of one cylindrical core 20A, while multiple high-potential wirings 51D~51F and multiple low-potential wirings 52D~52F of the other voltage supply device 100B are inserted through the through-holes 22 of the other cylindrical core 20B. In this way, multiple high-potential wirings 51A~51C (51D~51F) and multiple low-potential wirings 52A~52C (52D~52F) are inserted separately for each voltage supply device 100A (100B), making it less susceptible to voltage fluctuations between the pair of voltage supply devices 100A and 100B.

[0061] Figures 8(a) and (b) illustrate the effects of a configuration including high-potential wiring 51A and low-potential wiring 52A. As shown in Figure 8(a), the cylindrical core 20A and the block 30 connected to ground each act as electrodes, and the heat dissipation sheet 40 placed between the cylindrical core 20A and the metal block 30 connected to ground acts as a dielectric. Therefore, the portion from the cylindrical core 20A to the metal block 30 functions as the first capacitor C1.

[0062] Furthermore, the high-potential wiring 51A and the low-potential wiring 52A act as electrodes, and the resin covering the wires of the high-potential wiring 51A and the low-potential wiring 52A, as well as the space between the high-potential wiring 51A and the low-potential wiring 52A and the cylindrical core 20A, act as dielectrics. Therefore, the portion of the cylindrical core 20A from the high-potential wiring 51A and the low-potential wiring 52A functions as a second capacitor C2. When the first and second capacitors C1 and C2 function in this way, the cylindrical core 20A becomes a floating potential.

[0063] In other words, the first capacitor C1 and the second capacitor C2 are connected in series between the metal block 30 and the high-voltage high-potential side wiring 51A and the low-potential side wiring 52A. Therefore, the first capacitor C1 and the second capacitor C2 are connected in series between the metal block 30 and the high-potential side wiring 51A and the low-potential side wiring 52A. The first and second capacitors C1 and C2 formed in this way function like the Y capacitor 11 of the common-mode choke coil 10, as shown in Figure 8(b), and thus can suppress common-mode current. When comparing the capacitances of the first capacitor C1 and the second capacitor C2, the capacitance of the first capacitor C1 is greater than the capacitance of the second capacitor C2, so in effect, the second capacitor C2 functions as the Y capacitor 11.

[0064] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. [Explanation of Symbols]

[0065] 1: Inverter device, 2A~2F: Converter, 5A~5F: Gate drive circuit (drive circuit), 6A~6F: Switching element, 8: Guide member, 9A,9B: Power supply (DC power supply), 10: Common mode choke coil, 20A,20B: Cylindrical core, 22: Through hole, 40: Heat dissipation sheet, 51A~51F: High potential side wiring, 52A~52F: Low potential side wiring, 90: DC power supply, 100A,100B: Voltage supply device, 110: Output node, 120: Output terminal, 130: Control device, S: Accommodation space

Claims

1. Multiple switching elements connected in series, Multiple drive circuits for driving each of the multiple switching elements, Multiple converters that supply voltage to each of the multiple drive circuits, A common mode choke coil is provided between each of the plurality of converters and the power supply that supplies voltage to each converter, A voltage supply device comprising a switching element connected in series, which supplies a voltage with a waveform corresponding to the drive of the switching element, Each of the converters is connected to the power supply by a high-potential side wiring and a low-potential side wiring. The common mode choke coil comprises a cylindrical core with a through hole formed therein. A voltage supply device characterized in that a plurality of high-potential side wirings and a plurality of low-potential side wirings connected to each of the converters are inserted through the through-hole.

2. The voltage supply device according to claim 1, characterized in that the high-potential side wiring and the low-potential side wiring connected to each of the converters are twisted together in pairs.

3. An inverter device comprising a pair of voltage supply devices according to claim 1 or 2, which converts a DC voltage from a DC power supply connected to the pair of voltage supply devices into a pulse voltage and outputs it from an output terminal, The pair of voltage supply devices are connected to the output terminals, with the output node in between. The inverter device includes a control device that generates a pulse voltage from the DC voltage of the DC power supply by alternately controlling the drive circuits of one of the pair of voltage supply devices and the drive circuits of the other voltage supply device. The common mode choke coil has a pair of cylindrical cores, Of the pair of cylindrical cores, one cylindrical core is through which a plurality of the high-potential side wirings and a plurality of the low-potential side wirings of the one voltage supply device are inserted. An inverter device characterized in that a plurality of high-potential side wirings and a plurality of low-potential side wirings of the other voltage supply device are inserted through the other cylindrical core.

4. The pair of cylindrical cores are arranged side by side, A metal block having a cylindrical housing space formed for housing each of the parallel cylindrical cores, A heat dissipation sheet is disposed between the inner circumferential surface and the outer circumferential surface so as to contact the inner circumferential surface and the outer circumferential surface of the cylindrical core, which cover the outer circumferential surface of each cylindrical core and form the housing space of the block, The inverter device according to claim 3, further comprising:

5. The inverter device according to claim 4, characterized in that the block is electrically connected to ground, and the high-potential side wiring and the low-potential side wiring are wiring in which a conductive wire is covered with an insulating resin material.

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