JP2013090363A - Transformer - Google Patents

Abstract

A primary winding or a secondary winding is formed of a conductive plate, and is configured to switch a DC voltage applied to the primary winding. The wiring inductance is small, and the component arrangement for heat radiation design is reduced. Provision of transformers with a high degree of freedom.
A transformer in which a primary winding (3) or a secondary winding (4) is formed of a conductive plate and configured to switch a DC voltage applied to the primary winding (3). In this configuration, two lead portions 5 and 6 of the primary winding 3 or the secondary winding 4 formed of a conductive plate are overlapped with an insulator (not shown) interposed therebetween.
[Selection] Figure 1

Description

  The present invention relates to a transformer in which a primary winding or a secondary winding is formed of a conductive plate and configured to switch a DC voltage applied to a primary winding.

In a transformer that has a large transformation ratio and handles a large current, a structure in which a winding having a smaller number of turns is formed of a copper plate to increase the amount of current that can be flowed may be employed.
FIG. 4 is a block diagram illustrating a circuit example of a transformer that transforms by switching a DC voltage. In this transformer 18, the winding start side terminal of the primary winding 3 is connected to the plus terminal of the power source 11, and the switching element 12 is connected between the other side terminal of the primary winding 3 and the minus terminal of the power source 11. .

The winding start side terminal of the secondary winding 4 is connected to one terminal of the smoothing coil 16 and the cathode of the diode 17. The other terminal of the smoothing coil 16 is connected to each plus terminal of the smoothing capacitor 14 and the load 15.
The other terminal of the secondary winding 4 is connected to the cathode of the diode 13, and the anode of the diode 13 is connected to the anode of the diode 17 and the negative terminals of the smoothing capacitor 14 and the load 15.

  In the transformer 18 having such a configuration, when the switching element 12 is repeatedly turned on / off, the voltage V1 across the switching element 12 is 0 / V0 (output voltage of the power supply 11) as shown in the waveform diagram of FIG. 7A. ) Is repeated and when the voltage V1 at both ends is 0, the primary current I1 flows through the primary winding 3 as shown in FIG. 7B. By repeatedly passing / stopping the current I1 of the primary winding 3, the voltage V2 across the diode 13 is generated as shown in FIG. 7D. The secondary current I2 (FIG. 7C) of the secondary winding 4 and the conduction current I3 (FIG. 7E) of the diode 17 alternately flow according to the change of the voltage V2 across the terminals.

  In Patent Document 1, an opening is formed in a part of an annular body having a flat plate shape to provide an end portion, and a primary side and a secondary side conductive plate having a connection portion provided on the end side are formed. An inductance element is disclosed. At least one of these primary side and secondary side conductive plates is used, and the primary side and secondary side conductive plates are overlapped in an insulated state, and the plurality of used conductive plates are one of the upper conductive plates. Is connected to the other connecting portion of the lower conductive plate.

JP 2001-284130 A

  In the inductance element disclosed in Patent Document 1 in which the primary side and secondary side windings are formed of conductive plates, the winding extraction positions are separated from each other, and the wiring portion becomes long, so that it is difficult to reduce the wiring inductance. There's a problem. Further, in the transformer in which the winding is formed of a conductive plate and the DC voltage applied to the primary winding is switched as shown in FIG. 4, since the wiring inductance as described above exists, the switching element 12 is turned off. When this happens (FIG. 7A), as shown in FIG. 7D, there is a problem that a harmful surge occurs in the secondary voltage V2.

  In order to prevent such harmful surges from occurring, it is necessary to arrange the transformer and the rectifying element (diode 13) close to each other and shorten the wiring portion in order to reduce the wiring inductance. However, since each heat-resistant temperature is different, if they are placed close to each other, the heat radiation design must be designed according to the low heat-resistant temperature side (which is often a transformer), which limits the degree of freedom of component placement. There is also a problem.

  The present invention has been made in view of the circumstances as described above, and the primary winding or the secondary winding is formed of a conductive plate, and is configured to switch the DC voltage applied to the primary winding. It is an object of the present invention to provide a transformer having a small wiring inductance and a large degree of freedom in arranging parts for heat radiation design.

  A transformer according to a first aspect of the present invention is the transformer in which the primary winding or the secondary winding is formed of a conductive plate and configured to switch a DC voltage applied to the primary winding. Two lead portions of the formed primary winding or secondary winding are overlapped with an insulator interposed therebetween.

  In this transformer, the primary winding or the secondary winding is formed of a conductive plate, and switches a DC voltage applied to the primary winding. Two lead portions of a primary winding or a secondary winding formed of a conductive plate are overlapped with an insulator interposed therebetween.

  The transformer according to the second invention is configured such that the secondary winding is formed of a conductive plate, switches a DC voltage applied to the primary winding, and a rectifier element is connected in series to the secondary winding. In the transformer, the two lead portions of the secondary winding are overlapped with the first insulator interposed therebetween, and the second insulator is sandwiched between the lead portion on the side where the rectifying element is connected. It is characterized by comprising a heat sink.

  In this transformer, the secondary winding is formed of a conductive plate, switches a DC voltage applied to the primary winding, and a rectifier element is connected in series to the secondary winding. The two lead portions of the secondary winding are overlapped with the first insulator interposed therebetween, and the heat sink is close to the lead portion on the side where the rectifying element is connected with the second insulator interposed therebetween.

  According to the transformer of the present invention, the primary winding or the secondary winding is formed of a conductive plate, and is configured to switch the DC voltage applied to the primary winding. It is possible to realize a transformer with a high degree of freedom of component placement for design.

It is a disassembled perspective view which decomposes | disassembles and shows the principal part external appearance of embodiment of the transformer which concerns on this invention. It is explanatory drawing for demonstrating the production method of a secondary winding. It is a fragmentary sectional view showing the state where the secondary winding wound the column part of the 2nd core, and the bobbin inserted the secondary winding. It is a block diagram which shows the circuit example comprised so that it might transform by switching a DC voltage using a transformer. It is explanatory drawing for demonstrating the magnetic flux by each of the input current and output current which are passed through the two ends of the secondary winding. It is a fragmentary sectional view which shows the state which the secondary winding wound the cylindrical part of the 2nd core of embodiment of the transformer which concerns on this invention, and the bobbin inserted the secondary winding. It is a wave form diagram which shows the operation example of the transformer which transforms by switching DC voltage.

Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing an exploded appearance of a main part of a transformer according to a first embodiment of the present invention.
This transformer 18 has a rectangular bottom plate, two side plates that are erected so as to face each other from the two short sides of the bottom plate, and projects from the center of the bottom plate. The first core 1 includes a second core 7 having a side plate and a cylindrical portion that are aligned at the same height, and a top core that is substantially the same size as the bottom plate of the second core 7.

The transformer 18 is also fitted with a secondary winding 4 in which a conductive plate (for example, a copper plate) is formed in a cylindrical shape so as to wind the column part of the second core 7 and the secondary winding 4. A bobbin 2 around which a winding 3 is wound is provided.
As shown in FIG. 2A, the secondary winding 4 is provided with screw holes 8 and 9 for connection at opposing ends (drawers) 5 and 6 of the C-shaped conductive plate, In a state of being bent at a right angle to the other side of the figure at the broken line portion, as shown in FIG. 2B, the conductive plate is rolled into a cylindrical shape toward the front side of the figure. The end portions 5 and 6 overlap each other in a state where the conductive plates are rolled into a cylindrical shape.

The transformer 18 includes a first core in a state where the secondary winding 4 is wound around the cylindrical portion of the second core 7 and the bobbin 2 around which the primary winding 3 is wound is inserted into the secondary winding 4. A (top plate) 1 is manufactured so as to cover the two side plates of the second core 7, the cylindrical portion of the second core 7, and the bobbin 2.
FIG. 3 is a partial cross-sectional view showing a state in which the secondary winding 4 is wound around the cylindrical portion of the second core 7 and the bobbin 2 around which the primary winding 3 is wound is inserted into the secondary winding 4. There are portions of the secondary winding 4 that are rounded and overlapped with each other and the portions of the end portions 5 and 6 that are overlapped with each other between the portions of the secondary winding 4 with an insulating sheet (insulator) 10 interposed therebetween. There is no short circuit.

FIG. 4 is a block diagram showing an example of a circuit configured to transform the DC voltage by switching the DC voltage using the transformer 18.
In this transformer 18, the winding start side terminal of the primary winding 3 is connected to the plus terminal of the power source 11, and the switching element 12 is connected between the other side terminal of the primary winding 3 and the minus terminal of the power source 11. .

The winding start side terminal of the secondary winding 4 is connected to one terminal of the smoothing coil 16 and the cathode of the diode 17. The other terminal of the smoothing coil 16 is connected to each plus terminal of the smoothing capacitor 14 and the load 15.
The other terminal of the secondary winding 4 is connected to the cathode of the diode 13, and the anode of the diode 13 is connected to the anode of the diode 17 and the negative terminals of the smoothing capacitor 14 and the load 15.

  In the transformer 18 having such a configuration, when the switching element 12 is repeatedly turned on / off, the voltage V1 across the switching element 12 is 0 / V0 (output voltage of the power supply 11) as shown in the waveform diagram of FIG. 7A. ) Is repeated and when the voltage V1 at both ends is 0, the primary current I1 flows through the primary winding 3 as shown in FIG. 7B. By repeatedly passing / stopping the current I1 of the primary winding 3, the voltage V2 across the diode 13 is generated as shown in FIG. 7D. The secondary current I2 (FIG. 7C) of the secondary winding 4 and the conduction current I3 (FIG. 7E) of the diode 17 alternately flow according to the change of the voltage V2 across the terminals.

However, in the transformer 18 according to the present invention, since the end portions 5 and 6 of the secondary winding 4 overlap each other with the insulating sheet 10 interposed therebetween, the secondary current I2 is passed through the secondary winding 4. When flowing (FIG. 7C), as shown in FIG. 5, for example, the input current i1 flowing through the end 6 and the output current i2 flowing through the end 5 are in opposite directions.
As a result, the magnetic flux due to the input current i1 flowing through the end 6 and the output current i2 flowing through the end 5 cancel each other, and the inductance due to the wiring is reduced. The occurrence of surge is prevented or reduced.

(Embodiment 2)
FIG. 6 shows a second embodiment of the transformer according to the present invention, in which the secondary winding 4 is wound around the cylindrical portion of the second core 7 and the bobbin 2 around which the primary winding 3 is wound is the secondary. It is a fragmentary sectional view showing the state where winding 4 was inserted.
In this transformer 18a, a diode (rectifying element) 13 (FIG. 4) is connected to the end 6, and an insulating sheet (second insulator) 19 is sandwiched between the end 6 to which the diode 13 is connected. The heat sink 20 is close.

  In this way, by bringing the wiring (end portion 6) on the side connected to the diode 13 close to the heat sink 20, the heat generated in the diode 13 is transmitted to the windings 3 and 4 or the windings 3 and 4 It is possible to prevent the heat generated in step 1 from being transferred to the diode 13. Other configurations and operations are the same as the configurations and operations described in the first embodiment, and thus description thereof is omitted.

1 First core 2 Bobbin 3 Primary winding 4 Secondary winding 5, 6 End (drawer)
7 Second core 10 Insulation sheet (insulator)
11 Power supply 12 Switching element 13 Diode (rectifier element)
18, 18a Transformer 19 Insulation sheet (second insulator)
20 Heat sink

Claims (2)

In a transformer in which a primary winding or a secondary winding is formed of a conductive plate and is configured to switch a DC voltage applied to the primary winding,
A transformer in which two lead portions of a primary winding or a secondary winding formed of the conductive plate are overlapped with an insulator interposed therebetween. In the transformer in which the secondary winding is formed of a conductive plate, the DC voltage applied to the primary winding is switched, and a rectifier element is connected in series to the secondary winding.
The two lead portions of the secondary winding are overlapped with a first insulator interposed therebetween, and a heat sink is provided adjacent to the lead portion on the side where the rectifying element is connected with the second insulator sandwiched therebetween. Characteristic transformer.

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