JP2024053965A - Power Conversion Equipment - Google Patents

Abstract

[Problem] Even when the secondary side power is a low voltage/high current output, power loss and heat generation are reduced by minimizing electrical resistance, and this contributes to overall compactness and cost reduction. [Solution] In constructing a power conversion device including 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 conductor wire Ws, which has one end 3s connected to a bus bar plate 5 and the other end 3t connected to the circuit board Ub, thereby also serving as a fixing function for fixing the transformer unit Ut, and the choke coil 4 is made of a flat conductor wire Wc, which has one end 4s connected to the bus bar plate 5, thereby also serving as a fixing function for fixing the choke unit Uc. [Selected Figure] Figure 1

Description

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

Conventionally, the power conversion devices described in Patent Documents 1 to 3 are known as power conversion devices equipped with a circuit board including a transformer unit having a primary coil and a secondary coil, and a choke unit having a choke coil connected to the transformer unit.

The power conversion device of Patent Document 1 includes a power system main circuit section that is equipped with a transformer and a reactor and performs power conversion, a control circuit section that controls the operation of the power system main circuit section, an input filter circuit section that is provided between the AC power source and the power system main circuit section and attenuates the conductive noise contained in the input current using a choke coil and a capacitor, and an output filter circuit section that is provided between the power system main circuit section and an external load and attenuates the power supply noise contained in the output current using a choke coil and a capacitor.

The power conversion device of Patent Document 2 includes electronic components that configure a power conversion circuit, a control circuit board on which a control circuit that controls the power conversion circuit is formed, and a housing that has a first side wall and a second side wall that face each other and that houses the electronic components and the control circuit board. The power conversion circuit (converter circuit) includes, as electronic components, a transformer having a primary coil and a secondary coil, a primary electronic component that is connected to the primary coil to form a primary circuit, and a secondary electronic component that is connected to the secondary coil to form a secondary circuit. The transformer is disposed between the primary circuit and the secondary circuit, and the primary circuit and the secondary circuit are electrically insulated.

Furthermore, the power conversion device of Patent Document 3 aims to provide a power conversion device that can be simplified in structure. Specifically, the power conversion device includes a pair of power conversion units connected in parallel, a control board for controlling the power conversion units, and a housing that holds the control board. Each of the choke coil bus bars on the output side of the choke coil in each power conversion unit is configured to mechanically support the control board while electrically connecting the choke coil and the control board.

Patent No. 6486443 JP 2015-109759 A JP 2011-139598 A

However, the conventional power conversion devices described in the above-mentioned patent documents 1-3 had the following problems:

Firstly, in this type of power conversion device, coil components such as a transformer unit and a choke unit are mounted on a circuit board, and these coil components are connected via circuits on the board or specified leads. Furthermore, since it has the function of converting a primary voltage of about DC 400 [V] to a secondary voltage of about DC 10 [V], the secondary power is a low voltage/high current output. Therefore, from the perspective of further improving energy conservation by reducing power loss and heat generation, there was a problem in that the electrical resistance on the circuit connecting the components could not be ignored.

Secondly, because relatively large coil components such as the transformer unit and choke unit are mounted on the circuit board and wired (connected), there is a limit to how much the overall size, including the circuit board, can be reduced, even when the layout configuration is taken into consideration. Ultimately, there is room for further improvement in terms of further promoting the miniaturization and cost reduction of the entire power conversion device.

The present invention aims to provide a power conversion device that solves the problems that exist in the background art.

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 including 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 conductor wire Ws, which also serves as a fixing function for fixing the transformer unit Ut by connecting one end 3ma, 3mb to a bus bar plate 5 and the other end 3sa, 3sb to the circuit board Ub, and the choke coil 4 is made of a flat conductor wire Wc, which also serves as a fixing function for fixing the choke unit Uc by connecting one end 4s to the bus bar plate 5.

In this case, according to a preferred embodiment of the invention, the secondary coil 3 of the transformer unit Ut is configured by connecting the first coil portion 3a and the second coil portion 3b in series, and the connection portion 3c connecting the first coil portion 3a and the second coil portion 3b in series can function as a center tap 11. The transformer unit Ut can be provided with a transformer core 12 having a rectangular frame-like cross section, a primary coil 2 wound around the transformer core 12 in a bobbinless manner, and a secondary coil 3 facing the outer peripheral surface of the primary coil 2 and arranged in a bobbinless manner. On the other hand, the choke unit Uc can be provided with a choke core 13 having a rectangular frame-like cross section. Furthermore, the circuit board Ub can be provided with at least a part of an output circuit 14 that processes the output of the transformer unit Ut and the choke unit Uc.

The power conversion device 1 according to the present invention provides the following significant advantages:

(1) One end 3ma, 3mb of the secondary coil 3 using flat conductor wire Ws is connected to the bus bar plate 5, and the other end 3sa, 3sb is connected to the circuit board Ub, thereby also serving as a fixing function for fixing the transformer unit Ut, and one end 4s of the choke coil 4 using flat conductor wire Wc is connected to the bus bar plate 5, thereby also serving as a fixing function for fixing the choke unit Uc, so that the transformer unit Ut and the choke unit Uc can be connected over the shortest distance and fixed onto the circuit board Ub. As a result, even when the secondary power is a low-voltage/high-current output, the electrical resistance on the circuit connecting the components is minimized, power loss and heat generation are further reduced, and energy savings are further improved.

(2) Even when relatively large coil components such as the transformer unit Ut and the choke unit Uc are mounted and wired (connected) on the circuit board Ub, the wiring function can be achieved using the shortest distance and the fixing function to the circuit board Ub can be achieved, which not only makes the entire power conversion device 1 smaller and more compact, but also contributes to reducing overall costs, including material costs and manufacturing costs.

(3) In a preferred embodiment, the transformer unit Ut is provided with a secondary coil 3 formed by connecting the first coil portion 3a and the second coil portion 3b in series, and the connection portion 3c connecting the first coil portion 3a and the second coil portion 3b in series is made to function as a center tap 11. This allows the transformer unit Ut to be configured as a center tap transformer, making it easy to configure a center tap rectifier circuit.

(4) In a preferred embodiment, a transformer with a core can be constructed by providing the transformer unit Ut with a transformer core 12 having a rectangular frame-like cross section. This not only provides the advantages of a transformer with a core, but also ensures sufficient connection and fixing functions for the transformer with a core.

(5) In a preferred embodiment, a primary coil 2 wound in a bobbinless manner and a secondary coil 3 arranged in a bobbinless manner facing the outer peripheral surface of the primary coil 2 are provided on the transformer core 12 of the transformer unit Ut, thereby forming a bobbinless transformer unit Ut, which contributes to further miniaturization and cost reduction of the transformer unit Ut and the entire power conversion device 1.

(6) In a preferred embodiment, a choke coil with a core can be formed by providing the choke unit Uc with a choke core 13 having a rectangular frame-like cross section. This not only provides the advantages of a choke coil with a core, but also ensures sufficient connection and fixing functions for the choke coil with a core.

(7) In a preferred embodiment, if at least a part of the output circuit 14 that processes the output 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 the circuit board Ub including the output circuit 14, which can contribute to making the entire power conversion device 1 even smaller and more compact and reducing power loss.

FIG. 1 is an external perspective view of a power conversion device according to a preferred embodiment of the present invention; An electrical circuit diagram of the power conversion device; A component connection diagram of the power conversion device; FIG. 5 is a vertical cross-sectional side view of a transformer unit provided in the power conversion device; FIG. 4 is a cross-sectional view of the transformer unit taken along line A-A in FIG. FIG. 2 is an exploded perspective view of the transformer unit; FIG. 8 is a vertical cross-sectional side view of a choke unit provided in the power conversion device (cross-section taken along line D-D in FIG. 8); FIG. 7 is a cross-sectional rear view of the choke unit taken along line C-C in FIG. FIG. 2 is a perspective view of the components of the choke unit disassembled;

Next, we will present a preferred embodiment of the present invention and explain it in detail with reference to the drawings.

First, the main components of the power conversion device 1 according to this embodiment will be described with reference to Figures 1 to 9.

As shown in FIG. 3, the main components of the power conversion device 1 are a transformer unit Ut, a choke unit Uc, and a circuit board Ub. The circuit board Ub includes a board main body Ubm and a bus bar plate 5.

The specific structure of the transformer unit Ut is shown in Figures 4 to 6. As shown in Figure 6, the transformer unit Ut has, as its basic parts, a transformer core 12, a primary coil 2, and a secondary coil 3. Note that 21 indicates an insulating sheet, 22 indicates an insulating tape, and 23 indicates a heat dissipation sheet.

The transformer core 12 is constructed by combining a pair of core halves 12p, 12q formed to a predetermined length with a U-shaped cross section. The illustrated core halves 12p, 12q are ferrite cores. As a result, as shown in FIG. 6, by combining the open sides of each core half 12p, 12q facing each other and fixing the core halves 12p and 12q with insulating tape 22, an integrated transformer core 12 having a rectangular frame-shaped cross section can be constructed. In this way, by providing the transformer unit Ut with a transformer core 12 having a rectangular frame-shaped cross section, a cored transformer can be constructed, so that in addition to enjoying the benefits of a cored transformer, sufficient connection and fixing functions for the cored transformer can be ensured.

The primary coil 2 is formed by winding a typical magnet wire (single copper wire) Mw with a circular cross section to form a pair of coil halves 2a, 2b, which are then connected in series to form the primary coil 2. In the illustrated example, the input voltage is about 400 [V], and the total number of turns is about 20 turns. As shown in Figures 4 and 5, each coil half 2a... is wound into a rectangular frame shape and placed on the frame parts of the transformer core 12 that face each other at 180 [°]. An insulating coating is provided on the outer circumferential surface of the magnet wire Mw by applying multiple layers (three layers in the illustrated example).

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

As shown in FIG. 4, the other ends 3sa, 3sa located on the upper side of the first coil portion 3a are formed long enough to be connected to two connection holes 25x, 25x provided in the substrate main body portion Ubm described later, and the one end 3ma located on the lower side of the first coil portion 3a is formed short enough to be connected to the connection recess 26m provided in the bus bar plate 5 (center tap 11) located in front of the substrate main body portion Ubm. Furthermore, the other end 3sb located on the upper side of the second coil portion 3b is formed long enough to be connected to the connection hole 25y provided in the substrate main body portion Ubm, and the one end 3mb located on the lower side of the second coil portion 3b is formed short enough to be connected to the connection recess 26n provided in the bus bar plate 5 (center tap 11). Therefore, the bus bar plate 5 has a through window 26s through which the other end 3sb passes without contact, which is continuous with the connection recess 26m.

By providing a secondary coil 3 configured in this manner, the flat conductor wire Ws can be used to ensure both the connection function and the fixing function in a good and sufficient state, making it possible to implement this in an optimal form. In addition, since the transformer unit Ut can be configured as a center tap transformer, a center tap rectifier circuit can be easily configured.

The specific structure of the choke unit Uc is shown in Figures 7 to 9. As shown in Figure 9, the choke unit Uc has a choke core 13 and a choke coil 4 as its basic parts. Note that 31 indicates an insulating member and 32 indicates an insulating tape.

The choke core 13 is constructed by combining a pair of core halves 13p, 13q formed to a predetermined length with a U-shaped cross section. The illustrated core halves 13p, 13q are ferrite cores. As a result, as shown in FIG. 9, by combining the open sides of each core halves 13p, 13q facing each other and integrating them, a choke core 13 with a rectangular frame-like cross section can be constructed. The core halves 13p and 13q are fixed with insulating tape 32.

As shown in Figures 7-9, the choke coil 4 uses a rectangular conductor wire Wc, which is bent into an L-shape to form a choke coil with one turn. In this case, the tip 4s of the choke coil 4 is formed so that it can be connected to the connection recess 33 provided in the bus bar plate 5 shown in Figure 6. By providing a choke coil 4 configured in this way, the use of the rectangular conductor wire Wc can ensure both the connection function and the fixing function in a good and sufficient state, making it possible to implement it in an optimal form. In addition, by providing the choke unit Uc with a choke core 13 with a rectangular frame cross section, a cored choke coil can be formed, so that in addition to enjoying the benefits of a cored choke coil, sufficient connection and fixing functions for the cored choke coil can be ensured.

On the other hand, FIG. 3 shows the circuit board Ub. This circuit board Ub includes a board main body Ubm and a bus bar plate 5. In this case, at least a part of the output circuit 14 that processes the output of the transformer unit Ut and the choke unit Uc, specifically, at least a part of the output circuit 14 including the synchronous rectification MOSFETs 41 and 42, thermistor 43, and diodes (not shown) shown in FIG. 2, can be mounted on the board main body Ubm. In this way, by providing at least a part of the output circuit 14 that processes the output of the transformer unit Ut and the choke unit Uc on the circuit board Ub, a power supply unit can be constructed by combining the circuit board Ub including the output circuit 14, which can contribute to making the entire power conversion device 1 even smaller and more compact and reducing power loss.

One of the substrate surfaces (front side) of the substrate main body Ubm is the mounting surface for the MOSFETs 41, etc., and the other substrate surface (back side) has a circuit pattern formed thereon that is generally U-shaped, and as shown in FIG. 3, a pattern reinforcing plate 44 that covers this circuit pattern and an insulating plate 45 that covers this reinforcing plate 44 are provided. In addition, 44j denotes a connection terminal portion formed by extending a portion of the reinforcing plate 44, and 46 denotes a connector portion of the output circuit 14.

The bus bar plate 5 can also be made from a single copper plate, and this bus bar plate 5 also serves as a heat sink.

Next, the method of assembling these main components used in the power conversion device 1 according to this embodiment will be described with reference to Figures 1 to 9.

First, the core halves 12p and 12q are attached with their openings facing each other, and are integrated by wrapping insulating tape 22 around their outer periphery. This results in the transformer core 12, which is a rectangular frame in cross section, formed by combining the core halves 12p and 12q. Then, the coil halves 2a and 2b that make up the primary coil 2 are wound around this transformer core 12.

After that, as shown in FIG. 6, the first coil portion 3a and the second coil portion 3b that constitute the secondary coil 3 are prepared, and the first coil portion 3a is attached from the opening side so as to sandwich the coil half 2a of the primary coil 2, and the first coil portion 3b is attached 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 portion 3a and the first coil portion 3b. This state becomes the transformer unit Ut shown in FIG. 3.

In this way, by providing the primary coil 2 wound in a bobbinless manner on the transformer core 12 of the transformer unit Ut, and the secondary coil 3 facing the outer peripheral surface of the primary coil 2 and arranged in a bobbinless manner, a bobbinless transformer unit Ut can be constructed, which can contribute to further miniaturization and cost reduction of the transformer unit Ut and, in turn, the entire power conversion device 1.

Next, as shown in FIG. 9, core halves 13p and 13q are prepared and assembled with their openings facing each other, and insulating tape 32 is wrapped around the outer periphery to integrate them. This results in choke core 13, which is a rectangular frame in cross section, assembled from core halves 13p and 13q. Then, choke coil 4 shown in FIG. 7 and FIG. 9 is inserted into the inner hole of choke core 13 from one end opening, with tip 4s protruding from the other end opening, and insulating member 31 shown in FIG. 7 and FIG. 8 is placed in the empty gap in the inner hole of choke core 13 to adjust the gap. This state becomes choke unit Uc shown in FIG. 3.

3, the board body Ubm and bus bar plate 5 constituting the circuit board Ub are prepared. Then, the lower end 3ma of the first coil portion 3a of the transformer unit Ut is accommodated in the connection recess 26m provided in the bus bar plate 5 and connected by soldering or the like, and the lower end 3mb of the second coil portion 3b of the transformer unit Ut is accommodated in the connection recess 26n provided in the bus bar plate 5 and connected by soldering or the like. Similarly, the upper other 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 board body Ubm and connected by soldering or the like, and the upper other end 3sb of the second coil portion 3b of the transformer unit Ut is led to the board body Ubm through the through window 26s provided in the bus bar plate 5 and inserted into the connection hole 25y and connected by soldering or the like. The bus bar plate 5 can be fixed to the insulating plate 45 of the board main body portion Ubm by adhesive or other means.

Furthermore, as shown in FIG. 3, the tip 4s of the choke coil 4 in the choke unit Uc is inserted into a connection recess 33 formed in the bus bar 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). Thus, the tip 4s of the choke coil 4, the lower end 3ma of the first coil portion 3a in the secondary coil 3, and the lower end 3mb of the second coil portion 3b are commonly connected to the bus bar plate 5, and this bus bar plate 5 functions as a center tap 11. In this way, the integrated target power conversion device 1 shown in FIG. 1 can be obtained.

Figure 2 shows an electrical circuit diagram of the power conversion device 1. In Figure 2, 51a and 51b indicate input terminals, and 52a and 52b indicate output terminals. In the illustrated example, a switched pulse power signal of about DC 400 [V] is input to the input terminals 51a and 51b, and a switched pulse power signal of about DC 10 [V] is output to the output terminals 52a and 52b. In Figure 2, 53 indicates a control unit. Note that the same parts in the electrical circuit diagram of Figure 2 and the part connection diagram of Figure 3 are given the same reference numerals to clarify the configuration.

Therefore, according to the power conversion device 1 of this embodiment, as a basic configuration, it is equipped with a secondary coil 3 using a flat conductor wire Ws that also serves as a fixing function for fixing the transformer unit Ut by connecting one end 3ma, 3mb to the bus bar plate 5 and the other end 3sa, 3sb to the circuit board Ub, and a choke coil 4 using a flat conductor wire Wc that also serves as a fixing function for fixing the choke unit Uc by connecting one end 4s to the bus bar plate 5, so that the transformer unit Ut and the choke unit Uc can be connected by the shortest distance and fixed on the circuit board Ub. As a result, even if the secondary side power is a low voltage/high current output, the electrical resistance on the circuit connecting the components can be minimized, power loss and heat generation can be further reduced, and energy saving can be further improved. 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 wiring function can be achieved using the shortest distance and the fixing function to the circuit board Ub can be achieved, making the entire power conversion device 1 smaller and more compact, and contributing to reducing overall costs, including material costs and manufacturing costs.

Although the preferred embodiment has been described in detail above, the present invention is not limited to such an embodiment, and the detailed configuration, shape, material, quantity, method, etc. can be changed, added, or deleted as desired without departing from the gist of the present invention.

For example, the secondary coil 3 is shown as a case in which the first coil portion 3a and the second coil portion 3b are connected in series, and the connection portion 3c connecting the first coil portion 3a and the second coil portion 3b is configured as a center tap 11, but it may be a single secondary coil 3 without a center tap 11. Also, the transformer unit Ut is shown as a case in which a transformer core 12 having a rectangular frame-like cross section is provided, but the shape and material of the transformer core 12 are arbitrary, and the coreless type transformer unit Ut is not excluded. Similarly, the choke unit Uc is shown as a case in which a choke core 13 having a rectangular frame-like cross section is provided, but the shape and material of the choke core 13 are arbitrary, and the coreless type choke unit Uc is not excluded. Furthermore, the primary coil 2 wound around the transformer core 12 in a bobbinless manner, and the secondary coil 3 facing the outer circumferential surface of the primary coil 2 and arranged in a bobbinless manner are provided, but the winding form of the primary coil 2 and the secondary coil 3 is arbitrary and is not limited to the winding form exemplified. On the other hand, it is desirable to provide at least a part of the output circuit 14, which processes the output of the transformer unit Ut and the choke unit Uc, on the circuit board Ub, but this does not exclude the case where the output circuit 14 is provided on a separate board and the circuit board Ub is configured as a mounting board on which only the transformer unit Ut and the choke unit Uc are mounted. Note that various materials having similar functions (characteristics) can be used as the conductive material and insulating material.

The power conversion device according to the present invention can be used as a power conversion device in various power supply facilities, such as power supply facilities in data centers.

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

Claims (6)

A power conversion device including 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, the power conversion device being characterized in that the secondary coil is made of a rectangular conductor wire, one end of which is connected to a bus bar plate and the other end of which is connected to the circuit board, thereby also serving as a fixing function for fixing the transformer unit, and the choke coil is made of a rectangular conductor wire, one end of which is connected to the bus bar plate, thereby also serving as a fixing function for fixing the choke unit. The power conversion device according to claim 1, characterized in that the transformer unit includes a secondary coil in which a first coil section and a second coil section are connected in series, and the connection section in which the first coil section and the second coil section are connected in series functions as a center tap. The power conversion device according to claim 1, characterized in that the transformer unit has a transformer core with a rectangular frame-shaped cross section. 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 arranged in a bobbinless manner facing the outer peripheral surface of the primary coil. The power conversion device according to claim 1, characterized in that the choke unit is provided with a choke core having a rectangular frame-like cross section. The power conversion device according to claim 1, characterized in that the circuit board includes at least a part of an output circuit that processes the output of the transformer unit and the choke unit.

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