Converter unit

Abstract

The present invention provides a converter unit that ensures the isolation of the transformer while making the isolated converter compact and allowing the primary and secondary coils to be positioned appropriately relative to the core. [Solution] The converter unit 100 has an isolated converter 1A. The primary side circuit board 4A of the isolated converter 1A is integrally attached to the first coil board 3A so as to extend in a direction perpendicular to the first coil board 3A. The secondary side circuit board 4B of the isolated converter 1A is integrally attached to the second coil board 3B so as to extend in a direction perpendicular to the second coil board 3B. The first coil board 3A is held within the casing 20 by fixing the primary side circuit board 4A to one side wall 21A of the casing 20. The second coil board 3B is held within the casing 20 by fixing the secondary side circuit board 4B to the other side wall 21B of the casing 20.

Description

Technical Field

[0001] The present invention relates to a converter unit including an isolated converter including a transformer.

Background Art

[0002] For example, Patent Document 1 discloses an isolated converter including a transformer. The transformer is housed in an insulating casing. The transformer includes a primary coil and a secondary coil, and a core that magnetically couples them. The transformer is electrically connected to an inverter circuit board and a rectifier circuit board outside the casing. The transformer, the inverter circuit board (primary side circuit board), and the rectifier circuit board (secondary side circuit board) are housed in a metal casing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the primary side circuit board and the secondary side circuit board are housed in a metal casing while ensuring the insulation of the transformer with the casing, depending on their arrangement states, it is assumed that the overall size of the isolated converter will increase. In addition, for example, when one coil board having a primary coil and a secondary coil is provided, it is difficult to arrange the primary coil and the secondary coil at appropriate positions with respect to the core due to dimensional tolerances and assembly errors during manufacturing.

[0005] The present invention has been made in view of the above, and aims to provide a converter unit that ensures the insulation of the transformer, makes the size of the isolated converter compact, and allows the primary and secondary coils to be positioned appropriately relative to the core. [Means for solving the problem]

[0006] In view of the above problems, the converter unit according to the present invention is a converter unit having at least one isolated converter comprising a transformer having a primary coil and a secondary coil, and a core in which the primary coil and the secondary coil are electromagnetically coupled, and an insulating casing housing the transformer. The isolated converter comprises a first coil substrate on which a first coil pattern which will become the primary coil is formed, a second coil substrate on which a second coil pattern which will become the secondary coil is formed, a primary side circuit board electrically connected to the first coil pattern, and a secondary side circuit board electrically connected to the second coil pattern, all within the casing. The primary side circuit board is integrally attached to the first coil substrate so as to extend in a direction perpendicular to the first coil substrate, and the secondary side circuit board is integrally attached to the second coil substrate so as to extend in a direction perpendicular to the second coil substrate. The first coil substrate is held within the casing by fixing the primary circuit board to one of the pair of opposing side walls of the casing, and the second coil substrate is held within the casing by fixing the secondary circuit board to the other of the pair of opposing side walls of the casing.

[0007] According to the present invention, the primary circuit board is integrally attached to the first coil board, and the secondary circuit board is integrally attached to the second coil board. This allows the first coil board and the primary circuit board to be treated as a single, compact board structure, and the second coil board and the secondary circuit board to be treated as a single, compact board structure. The relative positions of the first coil board, the second coil board, the primary circuit board, and the secondary circuit board and the core can be easily managed, improving the workability of assembling the isolated converter.

[0008] Furthermore, the primary circuit board is integrally mounted to the first coil board so as to extend in a direction perpendicular to the first coil board, and the secondary circuit board is integrally mounted to the second coil board so as to extend in a direction perpendicular to the second coil board. As a result, the casing housing these boards can be made more compact compared to when these boards are arranged on the same plane. This allows for miniaturization of the isolated converter, thereby achieving a lower footprint.

[0009] Furthermore, by fixing the primary circuit board to which the first coil board is attached and the secondary circuit board to which the second coil board is attached to a pair of opposing side walls of the casing, it is possible to reduce deformation and distortion of these boards due to dimensional tolerances during mounting, compared to the case where the primary and secondary coils are provided on a single coil board. In addition, the first coil board and the second board can be mounted to the core with high precision.

[0010] In a more preferred embodiment, the core comprises a U-shaped core and an I-shaped core, and a magnetic circuit is formed by facing the pair of U-shaped ends of the U-shaped core toward the I-shaped core, the number of turns of the primary coil is greater than the number of turns of the secondary coil, and the first coil substrate is positioned closer to the I-shaped core than the second coil substrate.

[0011] According to this embodiment, by positioning the first coil substrate, which has a primary coil with more turns than the secondary coil, closer to the I-shaped core than the second coil substrate, the core can be brought closer to the potential of the primary coil. As a result, the potential of the core approaches that of the primary coil, which has a lower voltage than the secondary coil, and thus core discharge can be suppressed.

[0012] In a more preferred embodiment, the isolated converter comprises an input board electrically connected to the primary coil via the primary circuit board and equipped with an input terminal, and an output board electrically connected to the secondary coil via the secondary circuit board and equipped with an output terminal. Each of the primary and secondary circuit boards is fixed with a spacer that forms a gap between it and the inner surface of the side wall of the casing, and each of the primary and secondary circuit boards is fixed to the inner surface of the side wall of the casing by fastening the spacer and the fastener with the spacer sandwiched between them. Each of the input board and the output board is fixed to the outer surface of the side wall of the casing by fastening the fastener and the fastener with the fastener sandwiched between them.

[0013] In this embodiment, when the fasteners are released, the input board and output board can be removed from the outer surface of the casing's side wall. However, since the primary and secondary circuit boards are fixed to the inner surface of the casing's side wall by the fasteners, they remain fixed to the casing. In this state, when heated molding material is filled into the casing, the primary and secondary circuit boards are not affected by the flow of the molding material. Furthermore, since the input and output boards are removed from the casing, they are not affected by the heat of the molding material via the spacers and fasteners. As a result, electronic and electrical components can be selected for mounting on the input and output boards without considering the effects of the heat of the molding material.

[0014] In a more preferred embodiment, the core consists of a segmented core, which is sandwiched between a pair of retaining members, and the segmented core is connected to the retaining members by a pair of connectors. The retaining members have fixing portions formed therein for fixing the retaining members to the casing with fixing screws, and around the fixing portions, a channel is formed from one periphery of the retaining member to the other periphery through which the molding material to be filled into the casing flows.

[0015] According to this embodiment, since a channel is formed through which the mold material flows, the amount of air bubbles remaining on the surface of the retaining member inside the casing can be reduced, and the decrease in heat resistance caused by air bubbles can be suppressed.

[0016] In a more preferred embodiment, the converter unit includes a metal shield case attached to the casing so as to surround the portion of the casing in which one of the primary coils or the secondary coil is housed.

[0017] According to this embodiment, by covering the portion of the casing housing one of the coils of the isolated converter with a metal shielding case, the influence of an external magnetic field directed from outside the isolated converter toward the coil can be suppressed. This suppresses the generation of a voltage in the coil due to linked magnetic flux, and enables the isolated converter to stably output a voltage at the desired oscillation frequency.

[0018] In a more preferred embodiment, the isolated converter comprises an input board electrically connected to the primary coil and having an input terminal mounted on it, and an output board electrically connected to the secondary coil and having an output terminal mounted on it, wherein the input board is attached to the outer surface of one of a pair of side walls of the casing, and the output board is attached to the outer surface of the other of a pair of side walls of the casing, and the shield case is attached to the casing together with the input board and the output board, which of the two boards is electrically connected to the one coil.

[0019] In this embodiment, the shield case is attached to the casing together with one of the input and output boards, which is electrically connected to one of the coils. This allows the shield case and the board to be attached and detached together, and also suppresses the influence of external magnetic fields from the board to the coil electrically connected to it.

[0020] In a more preferred embodiment, the shield case extends along the outer wall of the casing in a direction from one of the input substrates to the other of the output substrates.

[0021] In this embodiment, since the shield case extends along the outer wall of the casing in the direction from one substrate to the other substrate, the influence of an external magnetic field directed from around the casing in which one coil of the isolated converter is housed toward the coil can be suppressed.

[0022] In a more preferred embodiment, the shield case extends from the side wall of the casing to which the one substrate is attached to the outer wall of the casing to which the core is housed.

[0023] According to this aspect, the shield case extends from the side wall of the casing to which one substrate is attached to cover the outer wall range of the casing in which the core is accommodated. Therefore, the shield case has a structure that covers the portion of the casing to which one coil is attached and does not cover the electronic components and the like connected to the other coil. As a result, the physical distance between these electronic components connected to the other coil and the shield case can be increased. Even if the potential difference between these electronic components connected to the other coil and the shield case becomes large, discharge between them can be suppressed.

[0024] As a more preferable aspect, the shield case is fixed to the side wall to which the one substrate is attached together with the one substrate so that the outer wall of the casing and the shield case are in a non-contact state.

[0025] According to this aspect, since the shield case is fixed to the side wall of the casing so that the outer wall of the casing and the shield case are in a non-contact state, a space can be formed between the shield case and the casing, preventing discharge from the secondary coil side where a high voltage is applied, and reducing the parasitic capacitance between the primary coil and the secondary coil.

[0026] As a more preferable aspect, the converter unit includes a plurality of the isolated converters. The plurality of isolated converters are attached to an insulating board in a state of being arranged in parallel at intervals, and the shield case is attached to the casing of each isolated converter so as to surround the plurality of isolated converters attached to the insulating board together with the insulating board.

[0027] According to this aspect, the insulating board can be used to arrange the isolated converters in parallel at intervals, so that the influence of the electric field and magnetic field generated inside the isolated converter on the adjacent isolated converter can be suppressed.

[0028] In a more preferred embodiment, one of the coils is a primary coil, one of the substrates is an input substrate, the primary coil is electrically connected to the input substrate via a primary side circuit board, the primary side circuit board is housed in the casing, and the shield case, together with the input substrate, is electrically connected to the primary side circuit board via a fixing connected to ground.

[0029] In this embodiment, the shield case is electrically connected to the primary circuit board together with the input board via a fixing device connected to earth, thereby fixing the potential between the shield case and the primary circuit board to ground potential and suppressing discharge between them. [Effects of the Invention]

[0030] According to the converter unit of the present invention, the influence of an external magnetic field on an isolated converter can be suppressed. [Brief explanation of the drawing]

[0031] [Figure 1] This is a schematic perspective view of a converter unit according to an embodiment of the present invention. [Figure 2] Figure 1 is a schematic perspective view of the converter unit from the other side. [Figure 3] Figure 1 is an exploded perspective view of the converter unit. [Figure 4] This is a cross-sectional view of the converter unit near the center, as shown in Figure 1. [Figure 5] This is a cross-sectional view of the converter unit shown in Figure 1, along its longitudinal direction. [Figure 6] Figure 1 is a schematic perspective view of an isolated converter. [Figure 7] Figure 1 is a schematic perspective view of an isolated converter seen from the other side. [Figure 8] Figure 7 is a schematic perspective view illustrating the first and second coil patterns of the coil substrate. [Figure 9] Figure 5 is a schematic perspective view of the retaining block. [Modes for carrying out the invention]

[0032] A converter unit according to an embodiment of the present invention will be described below with reference to Figures 1 to 9. Note that while Figures 1 to 9 depict the converter unit 100 with a defined top and bottom, these drawings and the description described later do not specify the top and bottom of the converter unit 100 during use.

[0033] 1. About the overall structure of converter unit 100 The converter unit 100 according to this embodiment includes isolated converters 1A and 1B, and a shield case 9 surrounding them. In this embodiment, the converter unit 100 has two isolated converters 1A and 1B attached by an insulating plate 8, but the number of these is not particularly limited as long as they can be enclosed by the shield case 9. Since the two isolated converters 1A and 1B have the same structure, one of the isolated converters 1A and 1B will be described below.

[0034] The isolated converter 1A is a DC-DC converter and includes a transformer 10A. The transformer 10A is an internal iron type transformer comprising first and second coil substrates 3A and 3B and a core 10. As shown in Figure 8, the first coil substrate 3A has a first coil pattern 36 which becomes the primary coil of the transformer 10A, and the second coil substrate 3B has a second coil pattern 37 which becomes the secondary coil of the transformer 10A. In this embodiment, the first and second coil substrates 3A and 3B are provided separately, but these first and second coil substrates 3A and 3B may be provided integrally. The core 10 electromagnetically couples the first coil pattern 36 and the second coil pattern 37.

[0035] The isolated converter 1A further comprises a primary circuit board and a secondary circuit board. In this embodiment, the primary circuit board is an inverter circuit board 4A, which is electrically connected to the first coil pattern 36 of the first coil board 3A. In this embodiment, the secondary circuit board is a rectifier circuit board 4B, which is electrically connected to the second coil pattern 37 of the second coil board 3B.

[0036] The inverter circuit board 4A is an inverter circuit formed by mounting electronic components 42, such as switching elements, on a substrate body (for example, a glass epoxy substrate) 40A on which a wiring pattern is provided. The inverter circuit board 4A converts DC power to AC power using the switching elements, and AC power is supplied to the first coil board 3A. The rectifier circuit board 4B is a rectifier circuit formed by mounting electronic components 44, such as diodes, on a substrate body (for example, a glass epoxy substrate) 40B on which a wiring pattern is provided, and rectifies the current (voltage) output from the second coil board 3B. Note that the inverter circuit and rectifier circuit in a DC-DC converter are generally known circuits, so a detailed explanation is omitted.

[0037] In this embodiment, a DC-DC converter is exemplified as the isolated converter 1A. However, if the isolated converter 1A is a switching type AC-DC converter, the primary side circuit board will be a rectifier circuit board that includes, for example, four additional diodes for AC-DC conversion. As a result, the AC-DC converter will have a configuration that includes an electrical circuit for AC-DC conversion and a DC-DC converter.

[0038] The isolated converter 1A further comprises an insulating casing 20. The casing 20 houses the transformer 10A, the inverter circuit board 4A, and the rectifier circuit board 4B. The casing 20 shown in Figures 6 and 7 is illustrated with the cover 29 shown in Figures 1 and 4 removed. The cover 29 can be removed by releasing the fasteners 79.

[0039] In this embodiment, the casing 20 is made of an insulating resin material. The resin material is not particularly limited as long as it can ensure insulating properties, and examples include engineering plastics. As an engineering plastic, it may be a crystalline plastic such as polyphenylene sulfide (PPS). Furthermore, from the viewpoint of ensuring heat resistance and strength, it is preferable to use an amorphous plastic made of polyetherimide (PEI), such as Ultem®.

[0040] The inverter circuit board 4A is positioned opposite one side wall 21A of the casing 20 with a gap between them, so as to extend along that side wall 21A. On the other hand, the rectifier circuit board 4B is positioned opposite the other side wall 21B of the casing 20 with a gap between them, so as to extend along that side wall 21B. Electronic components 63A and input terminals 64A are mounted on the outer surface of one side wall 21A of the casing 20, and an input board 6A mounted on the main board body 61A is attached to this input board 6A. The input board 6A is electrically connected to the inverter circuit board 4A and electrically connected to the primary coil via the inverter circuit board 4A.

[0041] On the outer surface of the other side wall 21B of the casing 20, electronic components 63B and output terminals 64B are mounted on the output board 6B which is mounted on the main board body 61B. The output board 6B is electrically connected to the rectifier circuit board 4B and electrically connected to the secondary coil via the rectifier circuit board 4B. Electronic components 63A, such as electrolytic capacitors, constitute part of a smoothing circuit that smooths the pulsating current input to the inverter circuit board 4A, and electronic components 63B, such as electrolytic capacitors, constitute part of a smoothing circuit that smooths the pulsating current output from the rectifier circuit board 4B.

[0042] In this embodiment, the input board 6A (output board 6B) is attached to the casing 20 by screwing (fastening) fasteners 72A (72B) to the fasteners 46A (46B). In this embodiment, the fasteners 46A (46B) are not screwed into the casing 20, but a portion of them is inserted through it and screwed (fastened) to spacers 45A (45B) fixed to the inverter circuit board 4A (rectifier circuit board 4B).

[0043] More specifically, a spacer 45A (45B) is provided between the inverter circuit board 4A (rectifier circuit board 4B) and the inner surface of the side wall 21A (21B) of the casing (20). This creates a gap between the inverter circuit board 4A (rectifier circuit board 4B) and the inner surface of the side wall 21A (21B) of the casing (20). The spacer 45A (45B) is fixed to the inverter circuit board 4A (rectifier circuit board 4B). The inverter circuit board 4A (rectifier circuit board 4B) is fixed to the inner surface of the side wall 21A (21B) of the casing (20) by fastening the spacer 45A (45B) and the fastener 46A (46B) together, with the spacer 45A (45B) and the fastener 46A (46B) sandwiched between the side wall 21A (21B). The input board 6A (output board 6B) is fixed to the outer surface of the side wall 21A (21B) of the casing 20 by fastening the fasteners 46A (46B) and 73A (73B) together while sandwiched between the fasteners 46A (46B) and 73A (73B).

[0044] As shown in Figure 5, a space SA (SB) is formed between the input board 6A (output board 6B) and the side wall 21A (21B) of the casing 20 to dissipate heat from the inverter circuit board 4A (rectifier circuit board 4B). Electronic components 63A (63B), and wiring connecting the input terminal 64A (output terminal 64B) to the inverter circuit board 4A (rectifier circuit board 4B) are housed in space SA (SB).

[0045] Core 10 electromagnetically couples the first coil pattern 36 and the second coil pattern 37 of the first and second coil substrates 3A and 3B (see Figure 5). Core 10 has segmented cores 11 and 12 that form a magnetic circuit, and the segmented cores 11 and 12 are molded bodies (e.g., compacted magnetic cores) formed from a soft magnetic material such as ferrite (iron). The segmented cores 11 and 12 are inserted through the first and second coil substrates 3A and 3B and sandwich the insulating sheet material 19. In this state, core 10 is sandwiched between retaining members 15 and 16 and connected by a pair of long screws 14 and 14.

[0046] In this embodiment, the divided core of the core 10 consists of a U-shaped core 11 and an I-shaped core 12. A magnetic circuit is formed by placing a pair of U-shaped ends of the U-shaped core 11 opposite the I-shaped core 12 and sandwiching an insulating sheet material 19 between them. The potential of the core 10 (U-shaped core 11 and I-shaped core 12) is the stray potential. The first coil substrate 3A is positioned closer to the I-shaped core 12 than the second coil substrate 3B. By positioning the first coil substrate 3A, which has a primary coil with more turns than the secondary coil, closer to the I-shaped core than the second coil substrate 3B, the potential of the I-shaped core 12 can be brought closer to the potential of the primary coil. By bringing the potential of the I-shaped core 12 closer to the potential of the primary coil, the potential of the U-shaped core 11 can also be brought closer to the potential of the primary coil. As a result, the potential of the core 10 approaches the potential of the primary coil, which has a lower voltage than the secondary coil, thus suppressing discharge from the core 10.

[0047] The core 10 assembled in this manner is attached to the casing 20. Specifically, the other retaining member 15 has a screw hole, and a fixing screw (fixing device) 77 is inserted through the upper wall 22 of the casing, the fixing screw 77 is screwed into the screw hole, and the fixing screw 77 is tightened. As a result, the core 10 is attached to the casing in a suspended state, floating above the lower wall 24 of the casing 20.

[0048] 2. Regarding the first and second coil substrates 3A and 3B The first and second coil substrates 3A and 3B have a first through-hole 31 that is inserted through the magnetic portion of the core 10 and a second through-hole 32 that is inserted through the second magnetic portion of the core 10. The first through-hole 31 and the second through-hole 32 are circular through-holes. In this embodiment, as shown in Figure 8, the first coil substrate 3A has a conductive first coil pattern 36 corresponding to the primary coil around the first through-hole 31. The second coil substrate 3B has a second coil pattern 37 corresponding to the secondary coil around the second through-hole 32. Specifically, the first and second coil substrates 3A and 3B are laminated substrates formed by stacking multiple single-layer substrates. Each single-layer substrate has an insulating substrate body such as a glass epoxy substrate, on which the first and second conductive patterns 36A and 37A are formed. In this embodiment, the number of turns of the primary coil is greater than the number of turns of the secondary coil, and the primary coil has a lower voltage than the secondary coil.

[0049] In this embodiment, of the stacked first conductive patterns 36A, only the outermost pair of first conductive patterns 36A are connected to the terminal portion 34A of the inverter circuit board 4A. The first conductive patterns 36A of adjacent single-layer substrates are insulated from each other by the substrate body having the insulating properties described above. The first conductive patterns 36A of adjacent single-layer substrates are electrically connected via first conductive vias 38 such that current flows in the same circumferential direction along the opening 31a of each first conductive pattern 36A. This forms a first coil pattern 36 corresponding to the primary coil of the transformer 10A.

[0050] In this embodiment, multiple groups of first conductive vias 38 (four in Figure 8) are arranged at equal intervals from the terminal portion 34A toward the opening 31a, with gaps between them. The first conductive pattern 36A located in the uppermost layer shown in Figure 8 and the first conductive pattern 36A located in the layer below it (second layer) are connected by a group of four first conductive vias 38 closest to the terminal portion 34A. Furthermore, the first conductive pattern 36A located in the lower layer (second layer) and the first conductive pattern 36A located in the layer below that (third layer) are connected to the aforementioned group of four first conductive vias 38 by a group of four first conductive vias 38 adjacent to the opening 31a. In this way, as the number of layers increases, the groups of multiple first conductive vias 38 connecting the first conductive patterns 36A are sequentially moved toward the opening 31a. In this way, as will be described later, the current flowing through the first coil pattern 36 flows along the periphery (circular edge) of the circular first insertion hole 31, thereby stabilizing the electric field formed in the first coil pattern 36.

[0051] In this embodiment, similarly, of the multiple second conductive patterns 37A, only the outermost pair of second conductive patterns 37A are connected to the terminal portion 34B to the rectifier circuit board 4B. The second conductive patterns 37A of adjacent single-layer substrates are insulated from each other by the substrate body having the insulating properties described above. The second conductive patterns 37A of adjacent single-layer substrates are electrically connected via second conductive vias 39 such that current flows in the same circumferential direction along the opening 32a of each second conductive pattern 37A. This forms a second coil pattern 37 corresponding to the secondary coil of the transformer 10A. In this embodiment, the number of turns of the first coil pattern 36 is greater than the number of turns of the second coil pattern 37.

[0052] In this embodiment, multiple groups of second conductive vias 39 (three in Figure 8) are arranged at equal intervals from the terminal portion 34B toward the opening 32a, with gaps between them. As the number of layers increases, the groups of second conductive vias 39 connecting the second conductive patterns 37A are sequentially moved toward the opening 32a. In this way, as will be described later, the current flowing through the second coil pattern 37 flows along the periphery (circumferential edge) of the circular second insertion hole 32, thereby stabilizing the electric field formed in the second coil pattern 37.

[0053] 3. Regarding the substrate structure including the first and second coil substrates 3A and 3B As shown in Figures 6 and 7, the inverter circuit board 4A is integrally attached to the first coil board 3A at one end of the first coil board 3A, extending in a direction perpendicular to the first coil board 3A. In this embodiment, the inverter circuit board 4A is arranged along one side wall 21A of the casing 20, and one end of the first coil board 3A is bonded to the surface of the inverter circuit board 4A on which the electronic components 42 are mounted (the surface of the board body). The first coil board 3A and the inverter circuit board 4A may be bonded by adhesive, or they may be integrated by a connecting jig or the like. In this embodiment, the inverter circuit board 4A and the first coil board 3A (the first coil pattern 36) are integrally and electrically connected by solder via connecting terminals 41 to which they are respectively connected.

[0054] Similarly, the rectifier circuit board 4B is integrally attached to the second coil board 3B such that it extends in a direction perpendicular to the second coil board 3B at the other end of the second coil board 3B. In this embodiment, the rectifier circuit board 4B is positioned along the other side wall 21B of the casing 20, and the other end (other side edge) of the second coil board 3B is bonded to the surface (surface of the board body) on which the electronic components 44 of the rectifier circuit board 4B are mounted. The second coil board 3B and the rectifier circuit board 4B may be bonded by adhesive, or they may be integrated by a connecting jig or the like. In this embodiment, the rectifier circuit board 4B and the second coil board 3B (the second coil pattern 37) are integrally and electrically connected by solder via connecting terminals 43 that connect them to each other.

[0055] According to this embodiment, the inverter circuit board 4A and the rectifier circuit board 4B are integrally mounted to the first and second coil boards 3A and 3B, respectively, so as to extend in directions perpendicular to the first and second coil boards 3A and 3B. Therefore, the internal space S of the casing 20 can be utilized more effectively compared to when these boards are arranged on the same plane. As a result, the casing 20 can be made more compact, and the isolated converter 1A can be miniaturized, thereby achieving a lower footprint.

[0056] Furthermore, by fixing the inverter circuit board 4A, to which the first coil board 3A is attached, and the rectifier circuit board 4B, to which the second coil board 3B is attached, to a pair of opposing side walls 21A and 21B of the casing 20, it is possible to reduce deformation and distortion of these boards due to dimensional errors during installation, etc., compared to the case where the primary and secondary coils are provided on a single coil board. In addition, the first coil board 3A and the second coil board 3B can be attached to the core 10 with high precision.

[0057] 4. Regarding molding onto casing 20 The internal space S of the casing 20 is filled with an insulating molding material, thereby sealing the transformer 10A, the inverter circuit board 4A, and the rectifier circuit board 4B within the internal space S of the casing 20. In this embodiment, it is preferable that the internal space S of the casing 20 is filled with a molding material M having a relative permittivity lower than that of the insulating material of the substrate bodies constituting the first and second coil substrates 3A and 3B. More preferably, the relative permittivity of the molding material is lower than that of the insulating material of the substrate bodies constituting the inverter circuit board 4A and the rectifier circuit board 4B.

[0058] The molding material M filled into the internal space S of the casing 20 ensures the voltage resistance of the transformer 10A, while the dielectric constant of the molding material M is lower than that of the insulating material of the substrate body, thereby suppressing an increase in parasitic capacitance caused by the molding material. When the insulating material of the substrate body is glass epoxy, its dielectric constant is 4.0, so it is preferable that the dielectric constant of the molding material M is less than 4.0 (for example, 2.0 to 3.0).

[0059] Electrolytic capacitors have a lower heat resistance temperature compared to other electronic components because they contain electrolytes and other materials. In view of this, in this embodiment, the electrolytic capacitor, which is part of the electronic component 63A, is mounted on the input board 6A and positioned outside the casing 20. This makes it possible to suppress the effect of heat transferred from the molding material to the electrolytic capacitor when filling the casing 20 with the molding material.

[0060] In particular, in this embodiment, when the fasteners 73A and 73B are released from the fasteners 46A and 46B, the input board 6A and the output board 6B can be removed from the outer surfaces of the side walls 21A and 21B of the casing 20. However, the inverter circuit board 4A and the rectifier circuit board 4B are fixed to the inner surfaces of the side walls 21A and 21B of the casing 20 by the fasteners 46A and 46B, respectively, through the fastening of spacers 45A and 45B. Therefore, the inverter circuit board 4A and the rectifier circuit board 4B remain fixed inside the casing 20. In this state, when heated molding material is filled into the casing 20, the inverter circuit board 4A and the rectifier circuit board 4B are not affected by the flow of the molding material. Furthermore, since the input board 6A and the output board 6B are removed from the casing 20, they are not affected by the heat of the molding material via the spacers 45A, 45B and fasteners 46A, 46B. As a result, the electronic and electrical components mounted on the input board 6A and the output board 6B can be selected without considering the effects of the heat of the molding material.

[0061] As shown in Figure 9, the retaining member 15 has a fixing portion 15a formed therein for fixing the retaining member 15 to the casing 20 with fixing screws 77. The fixing portion 15a is the part that includes a hole into which the fixing screws 77 are fastened. Around the fixing portion 15a, a flow path 15d is formed from one periphery (recess) 15g of the retaining member 15 to the other periphery (recess) 15h of the retaining member 15 through which the mold material to be filled into the casing 20 flows. In this embodiment, such a flow path 15d is formed by providing a wall portion 15f, etc. The retaining member 15 also has a hole 15c through which the mold material flows and a screw hole 15b into which the long screw 14 is fastened. Because the flow path 15d through which the mold material flows is formed in this way, it is possible to reduce the amount of air bubbles remaining on the surface of the retaining member 15 inside the casing 20 and suppress the decrease in heat resistance caused by air bubbles.

[0062] 5. About Shield Case 9 As shown in Figures 1 and 2, the shield case 9 is made of a cylindrical metal such as aluminum or stainless steel and covers multiple (for example, two) isolated converters 1A and 1B. The two isolated converters 1A and 1B are mounted on an insulating plate 8 in a spaced-out arrangement. The insulating plate 8 has multiple fastening holes 84, and the insulating plate 8 is fixed to the casing 20 by inserting fixing screws 71 through the fastening holes 84 and screwing them into the upper wall 22 of the casing 20. The shield case 9 is attached to the casing 20 of each isolated converter 1A and 1B so as to surround the two isolated converters 1A and 1B mounted on the insulating plate 8, together with the insulating plate 8. One end of the insulating plate 8 has a pair of protruding portions 83, 83 that are wider than the width of the shield case 9. Mounting holes 82 for attachment to external equipment are formed in the protruding portions 83.

[0063] As shown in Figures 1 to 5, the shield case 9 is a rectangular cylindrical member having an upper wall 91 facing the upper wall 22 of the casing 20 of each isolated converter 1A, 1B, a lower wall 93 facing the lower wall 24 of the casing 20 of each isolated converter 1A, 1B, and a pair of side walls 92, 92 connecting the upper wall 91 and the lower wall 93.

[0064] Openings 97 and 98 are formed at both ends of the shield case 9. A connection portion 95 for connecting to the isolated converter 1A is formed in opening 98 by a fixing device 73A. The connection portion 95 protrudes inward from the periphery of opening 98. The connection portion 95 is fixed to the isolated converter 1A via one of the four fixing devices 73A that fix the input board 6A to the casing, which is connected to ground. Specifically, the inverter circuit board (primary side circuit board) 4A is housed in the casing 20, and the shield case 9 is electrically connected to the inverter circuit board 4A together with the input board 6A via a fixing device 73A connected to ground. Since the shield case 9 is electrically connected to the inverter circuit board 4A together with the input board 6A via a fixing device 73A connected to ground, the potential of the shield case 9 and the reference potential of the inverter circuit board 4A can be fixed to the ground potential, thereby suppressing discharge between them. In the above example, the potential of the shield case 9 and the reference potential of the inverter circuit board 4A were fixed to the ground potential, but they may also be fixed to a different potential (for example, a lower potential within the inverter circuit board 4A).

[0065] Furthermore, a mounting wall 94 is formed at the opening 98 of the shield case 9 for attaching the shield case 9 to the casing 20 of the isolated converters 1A and 1B via fasteners 72. As described above, by forming a pair of protruding portions 83 on the insulating plate 8 and the mounting wall 94 at the opening 98 of the shield case 9, the isolated converters 1A and 1B can be inserted into the internal space of the shield case 9 from the opening 97 on the other side of the shield case 9. This allows the isolated converters 1A and 1B to be inserted into the shield case 9 from the correct direction, and the shield case 9 can cover the appropriate portion of the isolated converters 1A and 1B described later.

[0066] As shown in Figure 3, the shield case 9 is attached to the casing 20 so as to surround the portion of the casing 20 that houses one of the primary coils 36 and secondary coils 37 of the isolated converters 1A and 1B (in this embodiment, the primary coil 36). Specifically, the shield case 9 is attached to the casing 20 via fasteners 72A together with the input board 6A, which is electrically connected to one of the coils (in this embodiment, the primary coil 36) of the input board 6A and output board 6B. This allows the shield case 9 and the input board 6A to be attached and detached together, and also suppresses the influence of external magnetic fields from the input board 6A to the primary coil 36 electrically connected thereto.

[0067] The shield case 9 extends along the outer wall of the casing 20 in the direction from the input board 6A to the output board 6B. The outer wall here refers to the upper wall 22, the lower wall 24, the cover 29, and the wall portion 27 opposite the cover 29. Specifically, as shown in Figure 5, it is preferable that the shield case 9 extends from the side wall 21A of the casing 20 to which the input board 6A is attached, to the area of ​​the outer wall of the casing 20 to which the core 10 is housed. This makes it possible to suppress the influence of external magnetic fields directed toward the primary coils 36 from around the casing 20 that houses the primary coils 36 of the isolated converters 1A and 1B.

[0068] In particular, the shield case 9 extends from the side wall 21A of the casing 20 to which the input board 6A is attached, to the outer wall of the casing 20 to which the core 10 is housed. As a result, the shield case 9 covers the portion of the casing 20 to which the primary coil 36 is attached, but does not cover the electronic components 44 of the rectifier circuit board 4B and the electronic components 63B of the output board 6B that are connected to the secondary coil 37. This increases the physical distance between these electronic components 44 and 63B connected to the secondary coil 37 and the shield case 9, thus suppressing discharge between them even if the potential difference between these electronic components 44 and 63B connected to the secondary coil 37 and the shield case 9 becomes large.

[0069] In this embodiment, the shield case 9 is fixed to the side wall 21A to which the input substrate 6A is attached, together with the input substrate 6A, so that the outer wall of the casing 20 and the shield case 9 are in a non-contact state. As a result, as shown in Figure 4, gaps C1, C2, and C4 are formed between the casing 20 and the shield case 9, and a gap C3 can also be formed between the isolated converters 1A and 1B.

[0070] According to this embodiment, by covering the portion of the casing 20 housing the primary coil 36 of the isolated converters 1A and 1B with a metal shield case 9, the influence of an external magnetic field directed from outside the isolated converter 1A toward the primary coil 36 can be suppressed. This suppresses the generation of voltage in the primary coil 36 due to linked magnetic flux, allowing the isolated converters 1A and 1B to stably output a voltage at the desired oscillation frequency. As shown in Figure 5, it is preferable that the shield case 9 covers the core 10 (divided cores 11 and 12) in a side view of the converter unit 100. Strictly speaking, a voltage is generated when magnetic flux links with the secondary coil 37, which is not covered by the metal shield case 9, but since most of the magnetic flux passes through the core 10, which has a high relative permeability, sufficient effect can be obtained by covering the core 10 with the metal shield case 9 as described above.

[0071] In particular, the shield case 9 is fixed to the side wall of the casing so that it is not in contact with the outer wall of the casing 20. This allows gaps C1, C2, and C4 to be formed between the shield case 9 and the casing 20, preventing discharge from the high-voltage secondary coil 37 and reducing parasitic capacitance between the primary coil 36 and the secondary coil 37. In addition, the insulating plate 8 allows the isolated converters to be arranged side by side with spacing between them, thus suppressing the influence of electric and magnetic fields generated inside the isolated converters on adjacent isolated converters.

[0072] In this way, by providing a shield case 9 to prevent the self-excited inverter connected to the converter unit 100 from malfunctioning in a high-voltage and high-magnetic-field environment, the high-voltage inverter of the main circuit connected thereto, ranging from several kV to tens of kV, can be driven stably, and malfunctions of the high-voltage inverter can be prevented.

[0073] 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.

[0074] In this embodiment, the primary and secondary coils are formed on a coil substrate, but for example, these coils may be windings. Furthermore, in this embodiment, the portion of the casing housing the primary coil is covered with a shielding case, but for example, the portion of the casing housing the secondary coil may be covered with a shielding case. [Explanation of Symbols]

[0075] 1A, 1B: Isolated converter, 3A: First coil board, 3B: Second coil board, 4A: Inverter circuit board (primary side circuit board), 4B: Rectifier circuit board (secondary side circuit board), 6A: Input board, 6B: Output board, 9: Shield case, 10: Core, 10A: Transformer, 11: Split core (U-shaped core), 12: Split core (I-shaped core), 14: Long screw (connector), 20: Casing, 21A, 21B: Side wall, 22: Top wall (outer wall), 24: Bottom wall (outer wall), 36: First coil pattern (primary coil), 37: Second coil pattern (secondary coil), 45A, 45B: Spacer, 46A, 46B: Fastener, 64A: Input terminal, 64B: Output terminal, 73A, 73B: Fixing device, 100: Converter unit

Claims

1. A converter unit having at least one isolated converter comprising a transformer having a primary coil and a secondary coil, and a core in which the primary coil and the secondary coil are electromagnetically coupled, and an insulating casing housing the transformer, The aforementioned isolated converter is A first coil substrate on which a first coil pattern forming the primary coil is formed, A second coil substrate on which a second coil pattern forming the secondary coil is formed, A primary side circuit board electrically connected to the first coil pattern, A secondary circuit board electrically connected to the second coil pattern, The casing contains the following: The primary side circuit board is integrally attached to the first coil board so as to extend in a direction perpendicular to the first coil board. The secondary circuit board is integrally attached to the second coil board so as to extend in a direction perpendicular to the second coil board. The first coil substrate is held within the casing by fixing the primary circuit board to one of the pair of opposing side walls of the casing. A converter unit characterized in that the second coil substrate is held within the casing by fixing the secondary circuit substrate to the other side wall of a pair of opposing side walls of the casing.

2. The core comprises a U-shaped core and an I-shaped core, and a magnetic circuit is formed by facing the pair of U-shaped ends of the U-shaped core toward the I-shaped core. The number of turns of the primary coil is greater than the number of turns of the secondary coil. The converter unit according to claim 1, characterized in that the first coil substrate is positioned closer to the I-shaped core than the second coil substrate.

3. The aforementioned isolated converter is An input board is electrically connected to the primary coil via the primary side circuit board and has an input terminal mounted on it, The system includes an output board that is electrically connected to the secondary coil via the secondary circuit board and has an output terminal, Each of the primary and secondary circuit boards has a spacer fixed to it, which forms a gap between it and the inner surface of the side wall of the casing. The primary circuit board and the secondary circuit board are each fixed to the inner surface of the side wall of the casing by fastening the spacer and the fastener together while the spacer and fastener are sandwiched between the side wall. The converter unit according to claim 1, characterized in that each of the input board and the output board is fixed to the outer surface of the side wall of the casing by fastening the fastener and the fixing device together while the input board and the output board are sandwiched between the fastener and the fixing device.

4. The core consists of a segmented core, which is sandwiched between a pair of retaining members, and the segmented core is connected to the retaining members by a pair of connectors. The converter unit according to claim 1, characterized in that the retaining member has a fixing portion formed therein for fixing the retaining member to the casing with fixing screws, and a flow path is formed around the fixing portion, from one periphery of the retaining member to the other periphery, through which the molding material to be filled into the casing flows.

5. The converter unit according to any one of claims 1 to 4, characterized in that the converter unit comprises a metal shield case attached to the casing so as to surround the portion of the casing in which one of the coils, the primary coil and the secondary coil, is housed.

6. The aforementioned isolated converter is An input board electrically connected to the primary coil and equipped with an input terminal, The system comprises an output board electrically connected to the secondary coil and equipped with an output terminal, The input board is attached to the outer surface of one of the pair of side walls of the casing. The output board is attached to the outer surface of the other side wall of the pair of side walls of the casing. The converter unit according to claim 5, characterized in that the shield case is attached to the casing together with one of the input boards and the output board that is electrically connected to one of the coils.

7. The converter unit according to claim 6, characterized in that the shield case extends along the outer wall of the casing in a direction from one of the input boards and the output boards toward the other board.

8. The converter unit according to claim 7, characterized in that the shield case extends from the side wall of the casing to which the one substrate is attached to the outer wall of the casing to which the core is housed.

9. The converter unit according to claim 7, characterized in that the shield case is fixed together with the one substrate to the side wall to which the one substrate is attached, such that the outer wall of the casing and the shield case are in a non-contact state.

10. The converter unit comprises a plurality of the isolated converters, Multiple isolated converters are mounted on an insulating plate in a manner that allows for spacing between them. The converter unit according to claim 5, characterized in that the shield case is attached to the casing of each of the isolated converters so as to surround the plurality of isolated converters attached to the insulating plate together with the insulating plate.

11. The aforementioned coil is a primary coil, and the aforementioned substrate is an input substrate. The primary coil is electrically connected to the input board via the primary side circuit board. The primary side circuit board is housed in the casing. The converter unit according to claim 6, characterized in that the shield case is electrically connected to the primary circuit board together with the input board via a fixing device connected to ground.

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