Power converter

Abstract

To suppress power loss and heat generation caused by minimization of electric resistance even when secondary-side power is a low-voltage / high-current output, and make a contribution to entire downsizing and cost reduction.SOLUTION: Formed is a power conversion device comprising a circuit board Ub on which a choke unit Uc having a transformer unit Ut having a primary coil 2 and a secondary coil 3, and a choke coil 4 connected to the transformer unit Ut is mounted. The secondary coil 3 that uses a rectangular wire Ws having one end 3s connected to a bus bar plate 5 and the other end 3t connected to the circuit board Ub so as to obtain a fixing function of fixing the transformer unit Ut is provided, and further, the choke coil 4 that uses a rectangular wire Wc having one end 4s connected to the bus bar plate 5 so as to obtain a fixing function of fixing the choke unit Uc, is provided.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power conversion device including a circuit board on which a transformer unit and a choke unit are mounted.

Background Art

[0002] Conventionally, as a power conversion device including a circuit board on which a transformer unit having a primary coil and a secondary coil and a choke unit having a choke coil connected to the transformer unit are mounted, the power conversion devices described in Patent Documents 1 to 3 are known.

[0003] The power conversion device of Patent Document 1 includes a power system main circuit unit that mounts a transformer and a reactor to perform power conversion, a control circuit unit that controls the operation of the power system main circuit unit, and is provided between an AC power supply and the power system main circuit unit. An input filter circuit unit that attenuates conducted noise included in the input current by a choke coil and a capacitor, and an output filter circuit unit that is provided between the power system main circuit unit and an external load and attenuates power supply noise included in the output current by a choke coil and a capacitor.

[0004] Further, the power conversion device of Patent Document 2 includes electronic components constituting a power conversion circuit, a control circuit board on which a control circuit for controlling the power conversion circuit is formed, and first and second side walls facing each other. And a housing that houses the electronic components and the control circuit board inside. The power conversion circuit (converter circuit) includes, as electronic components, a transformer having a primary coil and a secondary coil, a primary side electronic component connected to the primary coil to form a primary side circuit, and a secondary side electronic component connected to the secondary coil to form a secondary side circuit. The transformer is disposed between the primary side circuit and the secondary side circuit, and has a configuration in which the primary side circuit and the secondary side circuit are electrically insulated.

[0005] Furthermore, the power conversion device described in Patent Document 3 aims to provide a power conversion device that can simplify the structure. Specifically, the power conversion device comprises a pair of power conversion units connected in parallel, a control board for controlling the power conversion units, and a housing for holding the control board. Each choke coil busbar on the output side of the choke coil in each power conversion unit is configured to electrically connect the choke coil to the control board while mechanically supporting the control board. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 6486443 [Patent Document 2] Japanese Patent Publication No. 2015-109759 [Patent Document 3] Japanese Patent Publication No. 2011-139598 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the conventional power conversion devices described in the aforementioned Patent Documents 1-3 had the following problems.

[0008] Firstly, this type of power converter mounts coil components such as transformer units and choke units on a circuit board, and connects these coil components via circuits on the board or predetermined leads. Moreover, since it has the function of converting a primary voltage of approximately DC 400[V] to a secondary voltage of approximately DC 10[V], the secondary power output is low voltage / high current. Therefore, from the viewpoint of further improving energy efficiency by reducing power loss and heat generation, the electrical resistance in the circuits connecting the components was a problem that could not be ignored.

[0009] Secondly, because relatively large coil components such as transformer units and choke units are mounted and wired (connected) on the circuit board, there are limits to reducing the overall size, including the circuit board, even when considering the layout configuration. Ultimately, there was room for further improvement from the perspective of further promoting the miniaturization, compactness, and cost reduction of the entire power conversion device.

[0010] The present invention aims to provide a power conversion device that solves the problems present in the background technology described above. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, the power conversion device 1 according to the present invention is characterized in that, when configuring a power conversion device comprising at least a transformer unit Ut having a primary coil 2 and a secondary coil 3 and a circuit board Ub on which a choke unit Uc having a choke coil 4 connected to the transformer unit Ut is mounted, the secondary coil 3 is made of a flat rectangular conductor Ws which also serves as a fixing function for fixing the transformer unit Ut by connecting one end 3ma, 3mb to a busbar plate 5 and the other end 3sa, 3sb to the circuit board Ub, and the choke coil 4 is made of a flat rectangular conductor Wc which also serves as a fixing function for fixing the choke unit Uc by connecting one end 4s to a busbar plate 5.

[0012] In this case, according to a preferred embodiment of the invention, the secondary coil 3 of the transformer unit Ut is configured by connecting a first coil section 3a and a second coil section 3b in series, and the connection section 3c formed by connecting the first coil section 3a and the second coil section 3b in series can function as a center tap 11. Furthermore, the transformer unit Ut can be provided with a transformer core 12 with a rectangular cross-section, and a primary coil 2 wound around this transformer core 12 without a bobbin, and a secondary coil 3 arranged opposite the outer surface of the primary coil 2 without a bobbin. On the other hand, the choke unit Uc can be provided with a choke core 13 with a rectangular cross-section. In addition, the circuit board Ub can be provided with at least a part of the output circuit 14 that processes the outputs of the transformer unit Ut and the choke unit Uc. [Effects of the Invention]

[0013] The power conversion device 1 according to the present invention provides the following remarkable effects.

[0014] (1) By connecting one end 3ma, 3mb of the secondary coil 3, which uses flat rectangular conductor Ws, to the busbar plate 5 and the other end 3sa, 3sb to the circuit board Ub, the transformer unit Ut is also fixed in place. Similarly, by connecting one end 4s of the choke coil 4, which uses flat rectangular conductor Wc, to the busbar plate 5, the choke unit Uc is also fixed in place. As a result, the transformer unit Ut and the choke unit Uc can be connected over the shortest distance and fixed on the circuit board Ub.

[0015] (2) Even when relatively large coil components such as the transformer unit Ut and the choke unit Uc are mounted on the circuit board Ub and wired (connected), the shortest distance wiring function and the fixing function to the circuit board Ub can be realized, thereby enabling the overall miniaturization of the power conversion device 1 and contributing to an overall cost reduction including material costs and manufacturing costs.

[0016] (3) In a preferred embodiment, the transformer unit Ut is provided with a secondary coil 3 formed by connecting a first coil section 3a and a second coil section 3b in series, and the connection section 3c formed by connecting the first coil section 3a and the second coil section 3b in series functions as a center tap 11. In this way, the transformer unit Ut can be configured as a center tap transformer, and a center tap rectifier circuit can be easily configured.

[0017] (4) In a preferred embodiment, if a transformer core 12 with a rectangular cross-section is provided on the transformer unit Ut, a core-type transformer can be constructed, thereby enjoying the advantages of a core-type transformer, as well as ensuring sufficient connection and fixing functions for the core-type transformer.

[0018] (5) In a preferred embodiment, if a primary coil 2 wound without a bobbin and a secondary coil 3 facing the outer surface of the primary coil 2 and arranged without a bobbin are provided on the transformer core 12 of the transformer unit Ut, a bobbinless transformer unit Ut can be constructed, which can contribute to further miniaturization and cost reduction of the transformer unit Ut and the entire power conversion device 1.

[0019] (6) In a preferred embodiment, if a choke core 13 with a rectangular cross-section is provided on the choke unit Uc, a choke coil with a core can be constructed, thereby enjoying the advantages of a choke coil with a core, and ensuring sufficient connection and fixing functions for the choke coil with a core.

[0020] (7) In a preferred embodiment, if at least a part of the output circuit 14 for processing the outputs of the transformer unit Ut and the choke unit Uc is provided on the circuit board Ub, a power supply unit can be constructed by combining it with the circuit board Ub including the output circuit 14, which can contribute to further miniaturization and reduction of power loss of the entire power conversion device 1.

Brief Description of the Drawings

[0021] [Figure 1] An external perspective view of the power conversion device according to a preferred embodiment of the present invention, [Figure 2] An electrical circuit diagram of the same power conversion device, [Figure 3] A component connection diagram of the same power conversion device, [Figure 4] A longitudinal cross-sectional side view of the transformer unit provided in the same power conversion device (section along line B-B in FIG. 5), [Figure 5] A partial longitudinal cross-sectional rear view of the same transformer unit (section along line A-A in FIG. 4), [Figure 6] A perspective view of each component of the same transformer unit disassembled, [Figure 7] A longitudinal cross-sectional side view of the choke unit provided in the same power conversion device (section along line D-D in FIG. 8), [Figure 8] A longitudinal cross-sectional rear view of the same choke unit (section along line C-C in FIG. 7), [Figure 9] A perspective view of each component of the same choke unit disassembled, 04>

Mode for Carrying Out the Invention

[0022] Next, preferred embodiments according to the present invention will be given and described in detail based on the drawings.

[0023] First, the main components of the power conversion device 1 according to the present embodiment will be described with reference to FIGS. 1-9.

[0024] The power converter 1 comprises, as shown in Figure 3, a transformer unit Ut, a choke unit Uc, and a circuit board Ub as its main components. The circuit board Ub includes a main board portion Ubm and a busbar plate 5.

[0025] The specific structure of the transformer unit Ut is shown in Figures 4-6. As shown in Figure 6, the transformer unit Ut comprises a transformer core 12, a primary coil 2, and a secondary coil 3 as its basic components. Note that 21 represents an insulating sheet, 22 represents insulating tape, and 23 represents a heat dissipation sheet.

[0026] The transformer core 12 is constructed by combining a pair of core halves 12p and 12q, each formed to a predetermined length with a U-shaped cross-section. The example core halves 12p and 12q are ferrite cores. As shown in Figure 6, by combining the open sides of each core half 12p and 12q and fixing the core halves 12p and 12q with insulating tape 22, an integrated transformer core 12 with a rectangular cross-section can be constructed. In this way, by providing the transformer unit Ut with a transformer core 12 with a rectangular cross-section, a transformer with a core can be constructed, thereby enjoying the advantages of a transformer with a core, as well as ensuring sufficient connection and fixing functions for the transformer with a core.

[0027] The primary coil 2 is constructed by winding a general-purpose magnet wire (single copper wire) Mw with a circular cross-section to form a pair of coil halves 2a and 2b, which are then connected in series. In this example, the input voltage is approximately 400 [V], and the total number of turns is approximately 20. Each coil halve 2a... is wound in a rectangular frame shape, as shown in Figures 4 and 5, and is placed in the frame portions of the transformer core 12 that are 180° opposite each other. The outer surface of the magnet wire Mw is coated with multiple layers (three layers in this example) of insulating coating to provide an insulating coating.

[0028] The secondary coil 3 is constructed by connecting a first coil section 3a and a second coil section 3b in series, and the connection section 3c connecting the first coil section 3a and the second coil section 3b functions as a center tap 11. As shown in Figures 4 and 6, the first coil section 3a and the second coil section 3b are each made using flat rectangular conductor Ws and bent into a U-shape to form a coil with one turn, and are connected via the connection section 3c to constitute a secondary coil 3 with a center tap. In this example, the output voltage of the secondary coil 3 is approximately 10 [V].

[0029] Furthermore, as shown in Figure 4, the other end 3sa, 3sa located above the first coil section 3a is formed to be longer so that it can be connected to two connection holes 25x, 25x provided in the substrate body section Ubm, which will be described later, while the one end 3ma located below the first coil section 3a is formed to be shorter so that it can be connected to a connection recess 26m provided in the busbar plate 5 (center tap 11) positioned in front of the substrate body section Ubm. In addition, the other end 3sb located above the second coil section 3b is formed to be longer so that it can be connected to a connection hole 25y provided in the substrate body section Ubm, while the one end 3mb located below the second coil section 3b is formed to be shorter so that it can be connected to a connection recess 26n provided in the busbar plate 5 (center tap 11).Therefore, a through-window 26s is formed in the busbar plate 5 that allows the other end 3sb to pass through without contact, and is continuous with the connection recess 26m.

[0030] By providing the secondary coil 3 configured in this way, both connection and fixing functions can be ensured in a good and sufficient state by using flat rectangular conductors Ws, thus enabling implementation in an optimal form. Furthermore, since the transformer unit Ut can be configured as a center-tapped transformer, a center-tapped rectifier circuit can be easily constructed.

[0031] On the other hand, the specific structure of the choke unit Uc is shown in Figures 7-9. As shown in Figure 9, the choke unit Uc comprises a choke core 13 and a choke coil 4 as basic parts. Note that 31 indicates an insulating member and 32 indicates insulating tape.

[0032] The choke core 13 is constructed by combining a pair of core halves 13p and 13q, each formed to a predetermined length with a U-shaped cross-section. The example core halves 13p and 13q are ferrite cores. As shown in Figure 9, by combining the open sides of each core half 13p and 13q and integrating them, a choke core 13 with a rectangular cross-section can be constructed. The core halves 13p and 13q are fixed together with insulating tape 32.

[0033] As shown in Figures 7-9, the choke coil 4 is formed by using a flat rectangular conductor Wc and bending it into an L-shape to create a choke coil with one turn. In this case, the tip 4s of the choke coil 4 is formed to be connectable to a connection recess 33 provided in the busbar plate 5 shown in Figure 6. By providing a choke coil 4 configured in this way, both connection and fixing functions can be ensured in a good and sufficient state by using a flat rectangular conductor Wc, thus making it an optimal configuration. Furthermore, by providing a choke core 13 with a rectangular cross-section in the choke unit Uc, a core-equipped choke coil can be constructed, allowing the advantages of a core-equipped choke coil to be enjoyed, as well as ensuring sufficient connection and fixing functions for the core-equipped choke coil.

[0034] On the other hand, Figure 3 shows the circuit board Ub. This circuit board Ub includes the main board portion Ubm and the busbar plate 5. In this case, at least a portion of the output circuit 14 that processes the outputs of the transformer unit Ut and the choke unit Uc can be mounted on the main board portion Ubm. Specifically, at least a portion of the output circuit 14, which includes the synchronous rectification MOSFETs 41 and 42 shown in Figure 2, thermistor 43, diodes (not shown), etc., can be mounted on the main board portion Ub. In this way, by providing at least a portion of the output circuit 14 that processes the outputs of the transformer unit Ut and the choke unit Uc on the circuit board Ub, a power supply unit can be constructed by combining it with the circuit board Ub including the output circuit 14, thereby contributing to further miniaturization and reduction of power loss for the entire power conversion device 1.

[0035] The main board portion Ubm has one surface (front) that serves as the mounting surface for MOSFETs 41, etc., while the other surface (back) has a circuit pattern that forms a U-shape overall. As shown in Figure 3, a pattern reinforcement plate 44 that covers this circuit pattern and an insulating plate 45 that covers the reinforcement plate 44 are provided. In addition, 44j is a connection terminal portion formed by extending a part of the reinforcement plate 44, and 46 is the connector portion of the output circuit 14.

[0036] Furthermore, the busbar plate 5 can be formed from a single copper plate, and this busbar plate 5 also serves as a heat sink.

[0037] Next, the assembly method of these main components used in the power converter 1 according to this embodiment will be described with reference to Figures 1-9.

[0038] First, the core halves 12p and 12q are mounted with their openings facing each other, and insulating tape 22 is wrapped around their outer surfaces to integrate them. This results in a transformer core 12 with a rectangular cross-section formed by combining the core halves 12p and 12q. Then, the coil halves 2a and 2b that constitute the primary coil 2 are wound around this transformer core 12.

[0039] Next, as shown in Figure 6, the first coil section 3a and the second coil section 3b that constitute the secondary coil 3 are prepared. The first coil section 3a is installed from the opening side so as to sandwich the coil half 2a of the primary coil 2, and the first coil section 3b is installed from the opening side so as to sandwich the coil half 2b of the primary coil 2. Then, an insulating sheet 21 is inserted between the first coil section 3a and the first coil section 3b. This state becomes the transformer unit Ut shown in Figure 3.

[0040] Thus, by providing a primary coil 2 wound without a bobbin on the transformer core 12 of the transformer unit Ut, and a secondary coil 3 facing the outer surface of the primary coil 2 and also arranged without a bobbin, a bobbinless transformer unit Ut can be constructed, which can contribute to further miniaturization and cost reduction of the transformer unit Ut and, furthermore, the entire power conversion device 1.

[0041] Next, as shown in Figure 9, core halves 13p and 13q are prepared, and they are assembled with their openings facing each other. An insulating tape 32 is then wrapped around the outer surface to integrate them. This results in a choke core 13 with a rectangular cross-section formed by combining core halves 13p and 13q. Then, the choke coil 4 shown in Figures 7 and 9 is inserted into the inner hole of the choke core 13 from one end opening, with its tip 4s protruding from the other end opening. The insulating member 31 shown in Figures 7 and 8 is then placed in the gap in the inner hole of the choke core 13 to adjust the gap. This state becomes the choke unit Uc shown in Figure 3.

[0042] Furthermore, as shown in Figure 3, the main board portion Ubm and the busbar plate 5 that constitute the circuit board Ub are prepared. Then, one lower end 3ma of the first coil portion 3a of the transformer unit Ut is placed in the connection recess 26m provided in the busbar plate 5 and connected by soldering or the like, and one lower end 3mb of the second coil portion 3b of the transformer unit Ut is placed in the connection recess 26n provided in the busbar plate 5 and connected by soldering or the like. Similarly, the other upper ends 3sa, 3sa of the first coil portion 3a of the transformer unit Ut are inserted into the respective connection holes 25x, 25x of the main board portion Ubm and connected by soldering or the like, and the other upper end 3sb of the second coil portion 3b of the transformer unit Ut is passed through the through window 26s provided in the busbar plate 5 to the main board portion Ubm and inserted into the connection hole 25y and connected by soldering or the like. The busbar plate 5 can be fixed to the insulating plate 45 of the main board Ubm by adhesive or other means.

[0043] Furthermore, as shown in Figure 3, the tip 4s of the choke coil 4 in the choke unit Uc is inserted into a connection recess 33 formed in the busbar plate 5 and connected by soldering or the like. The other end of the choke coil 4 is connected by soldering or the like to another circuit board (not shown in the figure). Therefore, the tip 4s of the choke coil 4, one lower end 3ma of the first coil portion 3a and one lower end 3mb of the second coil portion 3b of the secondary coil 3 are all commonly connected to the busbar plate 5, and this busbar plate 5 functions as a center tap 11. This makes it possible to obtain the integrated power conversion device 1 shown in Figure 1.

[0044] Figure 2 shows the electrical circuit diagram of the power converter 1. In Figure 2, 51a and 51b are input terminals, and 52a and 52b are output terminals. In this example, switched pulse power signals of approximately DC 400 [V] are input to input terminals 51a and 51b, and switched pulse power signals of approximately DC 10 [V] are output to output terminals 52a and 52b. In Figure 2, 53 indicates the control unit. The same parts in the electrical circuit diagram of Figure 2 and the component connection diagram of Figure 3 are denoted by the same reference numerals to clarify their configuration.

[0045] Therefore, according to the power converter 1 of this embodiment, the basic configuration includes a secondary coil 3 made of flat rectangular conductor Ws that also serves as a fixing function for fixing the transformer unit Ut by connecting one end 3ma, 3mb to the busbar plate 5 and the other end 3sa, 3sb to the circuit board Ub, and a choke coil 4 made of flat rectangular conductor Wc that also serves as a fixing function for fixing the choke unit Uc by connecting one end 4s to the busbar plate 5. As a result, the transformer unit Ut and the choke unit Uc can be connected over the shortest distance and fixed on the circuit board Ub. Furthermore, even when relatively large coil components such as the transformer unit Ut and choke unit Uc are mounted and wired (connected) on the circuit board Ub, the shortest distance wiring function and the ability to fix them to the circuit board Ub can be achieved. This enables the overall miniaturization of the power conversion device 1 and contributes to overall cost reduction, including material costs and manufacturing costs.

[0046] Although preferred embodiments have been described in detail above, the present invention is not limited to these embodiments, and the details of the configuration, shape, materials, quantity, method, etc., can be arbitrarily changed, added, or deleted without departing from the spirit of the present invention.

[0047] For example, the secondary coil 3 is shown as a configuration in which a first coil section 3a and a second coil section 3b are connected in series, and the connection section 3c connecting the first coil section 3a and the second coil section 3b is configured as a center tap 11. However, a single secondary coil 3 without a center tap 11 is also possible. Furthermore, the transformer unit Ut is shown as a case where a transformer core 12 with a rectangular cross-section is provided. However, the shape and material of the transformer core 12 are arbitrary, and this does not exclude a coreless type transformer unit Ut. Similarly, the choke unit Uc is shown as a case where a choke core 13 with a rectangular cross-section is provided. However, the shape and material of the choke core 13 are arbitrary, and this does not exclude a coreless type choke unit Uc. In addition, a configuration is shown in which a primary coil 2 wound around the transformer core 12 without a bobbin and a secondary coil 3 arranged opposite the outer surface of the primary coil 2 without a bobbin. However, the winding configuration of the primary coil 2 and secondary coil 3 is arbitrary and is not limited to the illustrated winding configuration. On the other hand, while it is desirable to provide at least a portion of the output circuit 14, which processes the outputs of the transformer unit Ut and the choke unit Uc, on the circuit board Ub, this does not preclude the case where the output circuit 14 is provided on a separate board, and the circuit board Ub is configured as a mounting board that only mounts the transformer unit Ut and the choke unit Uc. In addition, various materials with similar functions (characteristics) can be used for conductive and insulating materials. [Industrial applicability]

[0048] The power conversion device according to the present invention can be used as a power conversion device in various power supply equipment such as power supply equipment in data centers. [Explanation of symbols]

[0049] 1: Power converter, 2: Primary coil, 3: Secondary coil, 3ma: One end of secondary coil, 3mb: One end of secondary coil, 3sa: Other end of secondary coil, 3sb: Other end of secondary coil, 3a: First coil section, 3b: Second coil section, 3c: Connection section, 4: Choke coil, 4s: One end of choke coil, 5: Busbar plate, 11: Center tap, 12: Transformer core, 13: Choke core, 14: Output circuit, Ws: Flat rectangular wire, Wc: Flat rectangular wire, Ut: Transformer unit, Uc: Choke unit, Ub: Circuit board

Claims

1. A power conversion device comprising at least a transformer unit having a primary coil and a secondary coil, and a circuit board on which a choke unit having a choke coil connected to the transformer unit is mounted, characterized in that the secondary coil is made of a flat rectangular conductor that also serves as a fixing function for fixing the transformer unit by connecting one end to a busbar plate and the other end to the circuit board, and the choke coil is made of a flat rectangular conductor that also serves as a fixing function for fixing the choke unit by connecting one end to the busbar plate.

2. The power conversion device according to claim 1, wherein the transformer unit comprises a secondary coil formed by connecting a first coil section and a second coil section in series, and the connection section formed by connecting the first coil section and the second coil section in series functions as a center tap.

3. The power conversion device according to claim 1, characterized in that the transformer unit comprises a transformer core with a rectangular cross-section.

4. The power conversion device according to claim 3, characterized in that the transformer unit comprises the primary coil wound around the transformer core in a bobbinless manner, and the secondary coil facing the outer surface of the primary coil and arranged in a bobbinless manner.

5. The power conversion device according to claim 1, characterized in that the choke unit comprises a choke core with a rectangular cross-section.

6. The power conversion device according to claim 1, characterized in that the circuit board comprises at least a portion of an output circuit that processes the outputs of the transformer unit and the choke unit.

Images