Isolated DC-DC Converter

Abstract

To provide an insulated type DC-DC converter improved in productivity and maintainability.SOLUTION: A primary side unit 11 which has a DC side conductor connection 21 formed on one end side of a front face 20a of a housing 20 in which a plurality of semiconductor switching elements are unitized and an AC side conductor connection 22 formed on another end side is arranged so that the AC side conductor connection 22 is adjacent to a primary coil 31 of an isolation transformer 30. A secondary side unit 12 identically constituted as the primary side unit 11 is arranged at a position in point-symmetry around the isolation transformer 30 with respect to the primary side unit 11 so that the AC side conductor connection 22 is adjacent to a secondary coil 32 of the isolation transformer 30 and a front face is in the same direction as that of the front face 20a of the primary side unit 11.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a structure in which a unit of a converter section on the primary side and the secondary side is common in an isolated DC-DC converter of a DAB (Dual Active Bridge) circuit system. [Background technology]

[0002] Figure 1 shows a unit 1 that shares the primary and secondary AC / DC converters in a device with a pair of AC / DC converters, such as an existing UPS.

[0003] As shown in Figure 1(a), if unit 1 is arranged so that the positive pole 1P of the DC part of the AC / DC converter is on the bottom and the negative pole 1N is on the top, and then rotated 180 degrees in the direction of the arrow on the illustrated rotation axis (the axis connecting the front center and back center of unit 1), the top and bottom of the DC part will be swapped, and as a result, the positive pole 1P and negative pole 1N will be reversed as shown in Figure 1(b), and the unit will not be usable.

[0004] If different units are used for the primary-side AC / DC converter and the secondary-side AC / DC converter, two different types of units will have to be designed and manufactured, and if the structures are different, the maintenance methods will also be different, resulting in lower productivity compared to using a common unit.

[0005] However, if you rotate it around the rotation axis shown in Figure 2(a) (the axis connecting the center of the top and bottom of Unit 1), the polarity will not change, but the front and back of Unit 1 (shown as A and B) will be swapped, as shown in Figure 2(b).

[0006] Therefore, because the components on the front of the unit face the rear, maintenance of these components requires the unit to be removed or the device structure and installation conditions must allow access to the rear, making it impossible to perform front maintenance. For this reason, the unit structure must be devised.

[0007] Incidentally, a conventional inverter device in which a converter section corresponding to an inverter section is integrated into a unit is described, for example, in Patent Document 1, and a conventional cooling device for a transformer in a power conversion device is described, for example, in Patent Document 2. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 04-364368 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-187014 Summary of the Invention [Problem to be solved by the invention]

[0009] In the case of a control panel structure using a general unit, in the case of a circuit consisting of a primary side and a secondary side, such as a rectifier and an inverter, productivity of the unit can be improved by combining both into a unit and connecting them in parallel, as described in Patent Document 1. However, this has the problem of the unit becoming larger.

[0010] Furthermore, an isolated DC-DC converter includes an insulating transformer in its circuit. While air-cooling the transformer makes it possible to reduce its size, the cooling method described in Patent Document 2, for example, tends to increase costs by adding a fan, its power supply, and a control circuit.

[0011] The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide an isolated DC-DC converter with improved productivity and maintainability. [Means for solving the problem]

[0012] In order to solve the above problem, the isolated DC-DC converter according to claim 1 comprises: a plurality of semiconductor switching elements are unitized within a housing, and a primary unit having a DC side conductor connection portion formed at one end on the front side of the housing and an AC side conductor connection portion formed at the other end is disposed so that the AC side conductor connection portion is adjacent to a primary winding of an isolation transformer; A secondary unit having the same configuration as the primary unit is disposed in a position symmetrical to the primary unit with the isolation transformer as the center, with its AC conductor connection part adjacent to the secondary winding of the isolation transformer and its front facing in the same direction as the front of the primary unit.

[0013] The isolated DC-DC converter according to claim 2 is the one according to claim 1, The DC side conductor connection portion and AC side conductor connection portion of the primary side unit and the secondary side unit are each formed symmetrically above and below, with a midline extending horizontally from the midpoint in the vertical direction on the front of each housing as the axis of symmetry.

[0014] The isolated DC-DC converter according to claim 3 is the one according to claim 2, On the front of each housing of the primary unit and the secondary unit, two unit mounting boards are arranged symmetrically above and below with the connector portions of the boards facing the midline, with the midline as the axis of symmetry.

[0015] The isolated DC-DC converter according to claim 4 is the one according to claim 3, 4. The isolated DC-DC converter according to claim 3, wherein the two unit mounting boards are arranged so that the length of wiring connecting a control board provided outside the primary-side unit and the secondary-side unit to the unit mounting boards arranged in the primary-side unit is the same as the length of wiring connecting the control boards to the unit mounting boards arranged in the secondary-side unit.

[0016] The isolated DC-DC converter according to claim 5 is any one of claims 1 to 4, The inside of the primary unit and the inside of the secondary unit are cooled by cooling air from a cooling fan, and the insulating transformer is disposed on each exhaust side of the cooling air.

[0017] The isolated DC-DC converter according to claim 6 is any one of claims 1 to 5, The primary unit is configured as a single-phase DC / AC converter, and the secondary unit is configured as a single-phase AC / DC converter.

[0018] The isolated DC-DC converter according to claim 7 is any one of claims 1 to 5, The primary unit is configured as a three-phase DC / AC converter, and the secondary unit is configured as a three-phase AC / DC converter. [Effects of the Invention]

[0019] (1) According to the inventions described in claims 1 to 7, the primary and secondary units of the isolated DC-DC converter are configured as the same unit, which improves productivity and maintainability. Also, by keeping one spare unit in stock, either the primary or secondary unit can be replaced. (2) According to the invention described in claim 2, even if the primary unit and the secondary unit are turned upside down, the positions of the conductor connection parts to the AC side isolation transformer and the DC side device (DC power supply or load) are the same on the primary and secondary sides, so that the insulation distance needs to be checked and the connection positions need only be considered once, thereby shortening development time.

[0020] Furthermore, the same fixing screws and working tools are used in the conductor connecting portion, which makes the connecting work easier. (3) According to the invention described in claim 3, the mounting surface of the unit mounting board, such as the gate drive board, is only on the front side for both the primary unit and the secondary unit, which makes the connection work easier and allows for front maintenance. (4) According to the invention as set forth in claim 4, the lengths of the wires connecting the control board outside the unit to each of the primary and secondary units can be made uniform between the primary and secondary sides. (5) According to the invention as set forth in claim 5, the insulating transformer can be cooled by exhausting the cooling air from the primary unit and the secondary unit, thereby enabling the device to be made smaller and less expensive. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is an explanatory diagram showing a problem that occurs when a common unit for the primary and secondary sides of a conventional power converter is rotated in the direction of the rotation axis (1). [Figure 2] FIG. 1 is an explanatory diagram showing a problem that occurs when a common unit for the primary and secondary sides of a conventional power converter is rotated in the direction of the rotation axis (2). [Figure 3] 1 is a diagram showing the overall configuration of an isolated DC-DC converter according to an embodiment of the present invention; [Figure 4] FIG. 10 is an explanatory diagram of the conductors on the front side of the common unit in the embodiment of the present invention. [Figure 5] FIG. 10 is an explanatory diagram of a gate drive board on the front side of a common unit in an embodiment of the present invention. [Figure 6] FIG. 10 is an explanatory diagram showing the wiring length between a gate drive board in a common unit and a control board outside the unit in an embodiment of the present invention. [Figure 7] FIG. 3 is an explanatory diagram showing a cooling air path in an embodiment of the present invention. [Figure 8] 1 is a circuit diagram of a single-phase DAB circuit type isolated DC-DC converter to which the present invention is applied. [Figure 9] 1 is a circuit diagram of a three-phase DAB circuit type isolated DC-DC converter to which the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. Figure 3 shows the overall configuration of an isolated DC-DC converter according to an embodiment of the present invention. The isolated DC-DC converter in Figure 3 is housed, for example, in a panel not shown.

[0023] In FIG. 3, reference numeral 11 denotes a primary unit in which a plurality of bridge-connected semiconductor switching elements are unitized within a housing 20, and which has a DC side conductor connection portion 21 formed at one end of the front face 20a of the housing 20 and an AC side conductor connection portion 22 formed at the other end.

[0024] This primary side unit 11 is configured as a primary side DC / AC conversion section of an isolated DC-DC converter using a DAB circuit system, and is arranged so that the AC side conductor connection section 22 is adjacent to the primary winding 31 of the isolation transformer 30.

[0025] The DC side conductor connection portion 21 is provided with a positive electrode terminal 21Pa, a negative electrode terminal 21Na, a positive electrode terminal 21Pb, and a negative electrode terminal 21Nb, which are spaced apart from one another by a predetermined distance.

[0026] The positive electrode terminals 21Pa, 21Pb and the negative electrode terminals 21Na, 21Nb are connected to a DC power supply or a load (not shown).

[0027] AC terminals 22a to 22d are formed on the AC side conductor connecting portion 22 at predetermined intervals.

[0028] The AC terminals 22a to 22d are connected to one end of primary-side external terminals 41a to 41d, respectively, and the other ends of the external terminals 41a to 41d are connected to the primary winding 31 of the isolation transformer 30, respectively.

[0029] As shown in FIG. 4 described later, the DC side conductor connection portion 21 and the AC side conductor connection portion 22 are each formed symmetrically in the up-down direction, with a midline extending laterally from the midpoint in the up-down direction of the front surface 20a of the housing 20 as the axis of symmetry.

[0030] On the front surface 20a of the housing 20, gate drive boards (unit mounting boards) 23a, 23b are arranged symmetrically above and below, with the connector portions 23ac, 23bc of the boards facing a midline extending horizontally from the midpoint of the front surface 20a of the housing in the vertical direction, with the midline as the axis of symmetry.

[0031] The gate drive boards 23a and 23b have the function of receiving signals from a control board (shown in FIG. 6, which will be described later) outside the unit and driving the semiconductor switching elements in the housing 20 to turn on and off.

[0032] A secondary unit 12 is configured identically to the primary unit 11, and is disposed in a position point-symmetrical with respect to the primary unit 11 with the isolation transformer 30 as the center, with the AC side conductor connection part 22 adjacent to the secondary winding 32 of the isolation transformer 30, and with the front surface 20a oriented in the same direction as the front surface 20a of the primary unit 11.

[0033] This secondary unit 12 is configured as a secondary AC / DC conversion section of an isolated DC-DC converter of the DAB circuit type, and the positive terminals 21Pa, 21Pb and negative terminals 21Na, 21Nb are connected to a load or DC power supply not shown.

[0034] The AC terminals 22a to 22d of the secondary unit 12 are connected to one end of secondary external terminals 41a to 41d, respectively, and the other ends of the external terminals 41a to 41d are connected to the secondary winding 32 of the isolation transformer 30.

[0035] Reference numeral 51 denotes a mounting base on which the primary unit 11 is placed, 52 denotes a mounting base on which the secondary unit 12 is placed, and 53 denotes a mounting base on which the isolation transformer 30 is placed.

[0036] Fig. 4 shows the conductor arrangement of the shared primary unit 11 and secondary unit 12 as viewed from the front side. As shown in Fig. 4, the two conductors (DC side conductor connection part 21, AC side conductor connection part 22) are respectively arranged symmetrically above and below, with a midline 54 extending horizontally from the midpoint in the vertical direction of the front surface 20a of each housing 20 as the axis of symmetry. Note that the reference numerals 60 in the figure indicate fixing screws for connection.

[0037] By arranging them in this way, even if the unit is turned upside down, the positions of the conductor connections to the device side (the DC power supply side and isolation transformer side shown in Figure 8 described below) are the same for the primary and secondary sides, and the insulation distance needs to be checked and the connection positions considered only once, thereby shortening development time.In addition, because the conductor fixing screws 60 and work tools are also the same, the primary and secondary side connection work can be done by memorizing one set of tools and work procedures during manufacturing and maintenance.

[0038] The unit's board layout is also symmetrical from top to bottom, with connectors 23ac and 23bc of gate drive boards 23a and 23b positioned toward the center of the unit, as shown in Figure 5. This means that even if the unit is turned upside down, the direction in which the wires are pulled out is simply reversed, so they do not end up on the bottom or back of the unit. Also, by being able to use the unit in a reversible state, the length of the wires connecting from the control board (equipped with a CPU) inside the control panel to the gate drive board can be aligned on the primary and secondary sides, as shown in Figure 6.

[0039] In Figure 6, 70 is a control board inside a control panel equipped with a CPU, and is arranged so that the length of wiring 71a connecting the gate drive board 23a of the primary unit 11 to the control board 70 is the same as the length of wiring 72a connecting the gate drive board 23a of the secondary unit 12 to the control board 70.

[0040] In addition, the length of the wiring 71b connecting the gate drive board 23b of the primary unit 11 and the control board 70 is arranged to be the same as the length of the wiring 72b connecting the gate drive board 23b of the secondary unit 12 and the control board 70.

[0041] The primary unit 11 and secondary unit 12 are forced-air cooled by fans to cool the internal semiconductor elements, but in this embodiment, the exhaust air from these units is used to cool the isolation transformer 30 between the DC / DC converters as shown in FIG. 7.

[0042] 7 shows the relative positions of the primary unit 11, the isolation transformer 30, and the secondary unit 12, and does not show external terminals 41a to 41d, wiring, etc. The interiors of the primary unit 11 and the secondary unit 12 are cooled by cooling air from cooling fans (not shown), and an isolation transformer 30 is disposed on each exhaust side of the cooling air.

[0043] With this configuration, the cooling air path shown in FIG. 7 allows the air that has passed through both units 11 and 12 to cool the isolation transformer 30 from the left and right, making it possible to reduce the size of the isolation transformer 30. Furthermore, there is no need for a fan dedicated to cooling the isolation transformer 30 or a duct dedicated to exhausting the units, which leads to a more compact and less expensive device.

[0044] This type of usage is also an advantage of rotating the two units 11 and 12 so that they are point symmetrical and flipped upside down. [Example]

[0045] A first embodiment will be described in which the configuration of the present invention is applied to a single-phase isolated DC-DC converter of a DAB circuit type shown in Fig. 8. In Fig. 8, a primary-side unit 11 is configured as a single-phase DC / AC conversion unit in which semiconductor switching elements S1 to S4 are connected in a single-phase bridge. A DC power supply 81 is connected between the positive and negative terminals of the DC side, and the AC side is connected to a primary winding 31 of an isolation transformer 30.

[0046] The secondary unit 12 is configured as a single-phase AC / DC conversion unit in which semiconductor switching elements S5 to S8 are connected in a single-phase bridge, and a DC power supply 82 is connected between the positive and negative terminals of the DC side, and the AC side is connected to the secondary winding 32 of the isolation transformer 30.

[0047] The primary side single-phase DC / AC conversion unit (11) and the secondary side single-phase AC / DC conversion unit (12) are a common unit.

[0048] The DC power supply 81 (82) in Fig. 8 is located outside the unit and is electrically connected to the unit by the conductor (DC side conductor connection part 21) shown in Fig. 4. The DC power supply 82 on the output side in Fig. 8 may be replaced with a load device.

[0049] In an isolated DC-DC converter using the DAB circuit system, the input and output of the isolation transformer are AC, and even if the unit is reversed, the primary and secondary functions can be switched using an output signal from the control board, so the present invention can be applied. This is also true for Example 2, which will be explained next. [Example]

[0050] A second embodiment will be described in which the configuration of the present invention is applied to a three-phase DAB circuit type isolated DC-DC converter shown in Fig. 9. In Fig. 9, a primary unit 11 is configured as a three-phase DC / AC conversion unit in which semiconductor switching elements S1 to S6 are connected in a three-phase bridge. A DC power supply 91 is connected between the positive and negative terminals of the DC side, and the AC side is connected to a primary winding 31 of an isolation transformer 30.

[0051] The secondary unit 12 is configured as a three-phase AC / DC conversion unit in which semiconductor switching elements S7 to S12 are connected in a three-phase bridge, and a DC power supply 92 is connected between the positive and negative terminals of the DC side, and the AC side is connected to the secondary winding 32 of the isolation transformer 30.

[0052] The primary side three-phase DC / AC conversion unit (11) and the secondary side three-phase AC / DC conversion unit (12) are a common unit.

[0053] As described above, according to this embodiment, the following effects can be expected.

[0054] -Productivity is improved because the primary and secondary sides are the same unit.

[0055] · If you keep one spare unit, you can replace either the primary or secondary side.

[0056] · Checking the insulation distance and considering the connection positions only needs to be done once, shortening development time.

[0057] The gate drive board mounting surface is only on the front side, making connection work easier and enabling front maintenance.

[0058] · The conductor fixing screws and work tools are standardized, making connection work easier.

[0059] -The length of the wiring connected from the control board inside the panel can be made the same on the primary and secondary sides.

[0060] The insulation transformer can be cooled by the exhaust from the primary unit 11 and the secondary unit 12, which allows for miniaturization and cost reduction. [Explanation of symbols]

[0061] 11...Primary unit 12...Secondary unit 20…Case 20a...Front 21... DC side conductor connection part 21Pa,21Pb…Positive terminal 21Na,21Nb…Negative terminal 22...AC side conductor connection part 22a~22d…AC terminal 23a, 23b...Gate drive board 23ac, 23bc...Connector part 30...Isolation transformer 31...Primary winding 32...Secondary winding 41a~41d...External terminals 60...Fixing screw 70...Control board 71a, 71b, 72a, 72b...Wiring 81,82,91,92…DC power supply S1 to S12: Semiconductor switching elements

Claims

1. a plurality of semiconductor switching elements are unitized within a housing, and a primary unit having a DC side conductor connection portion formed at one end on the front side of the housing and an AC side conductor connection portion formed at the other end is disposed so that the AC side conductor connection portion is adjacent to a primary winding of an isolation transformer; an isolated DC-DC converter, characterized in that a secondary unit configured identically to the primary unit is disposed in a position that is point-symmetrical with respect to the primary unit, with the isolation transformer as the center, with its AC side conductor connection portion adjacent to the secondary winding of the isolation transformer, and with its front surface facing the same direction as the front surface of the primary unit.

2. 2. The isolated DC-DC converter according to claim 1, wherein the DC side conductor connection portions and the AC side conductor connection portions of the primary side unit and the secondary side unit are respectively formed symmetrically above and below, with a midline extending horizontally from the midpoint in the up-down direction on the front surface of each housing as the axis of symmetry.

3. 3. The isolated DC-DC converter according to claim 2, wherein two unit mounting boards are disposed on the front of each housing of the primary unit and the secondary unit, with their connector portions facing the midline and arranged symmetrically above and below with the midline as an axis of symmetry.

4. 4. The isolated DC-DC converter according to claim 3, wherein the two unit mounting boards are arranged so that the length of wiring connecting a control board provided outside the primary unit and the secondary unit to the unit mounting board arranged in the primary unit is the same as the length of wiring connecting the control board to the unit mounting board arranged in the secondary unit.

5. 5. The isolated DC-DC converter according to claim 1, wherein the inside of the primary unit and the inside of the secondary unit are each cooled by cooling air from a cooling fan, and the isolation transformer is disposed on each exhaust side of the cooling air.

6. 6. The isolated DC-DC converter according to claim 1, wherein the primary side unit is configured as a single-phase DC / AC conversion unit, and the secondary side unit is configured as a single-phase AC / DC conversion unit.

7. 6. The isolated DC-DC converter according to claim 1, wherein the primary side unit is composed of a three-phase DC / AC conversion unit, and the secondary side unit is composed of a three-phase AC / DC conversion unit.

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