JP2002033220A - Large-current push-pull type step-up transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen the thermal loss of a push-pull type step-up transformer due to the primary windings of the transformer and to enable an increase in the capacities of the secondary outputs of the transformer. SOLUTION: Conductor plates, such as busbars formed by integrally constituting the intermediate terminal parts of the transformer, are used as the primary windings of the transformer, the secondary windings of the transformer are respectively inserted in the sides of the inner peripheries of the primary winding conductors bent into a cylindrical shape of the transformer via each insulator and moreover, the conductor plates are fixed on each other by an electrical insulating material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push-pull type step-up transformer used in a step-up circuit for stepping up a low DC voltage to a high DC voltage.

[0002]

2. Description of the Related Art In a push-pull type step-up transformer, a large current flows on a low-voltage primary side in order to ensure a high-voltage output on a secondary side. For this reason, conventionally,
The heat loss due to the primary conductor was large, and the secondary output was greatly limited. In particular, it is necessary to use a thin copper wire for the intermediate terminal due to the wiring structure, which causes a large heat loss, and it is difficult to obtain a large capacity as a secondary output.

[0003]

FIG. 7 is a block diagram showing a push-pull type boost switching power supply circuit. The circuit is composed of a primary low-voltage DC power supply 30 composed of a battery or the like, a semiconductor bridge circuit, and the like, and includes a switching circuit 20 that converts a DC voltage into a primary low-voltage AC voltage, a switching circuit 20, and a secondary rectifier circuit 50. PW composed of driving semiconductor elements, etc.
A drive circuit 40 for performing M control, etc., a push-pull type step-up transformer 10 ′ for converting a primary low voltage AC voltage to a secondary high voltage AC voltage, a semiconductor bridge circuit, etc. It comprises a rectifier circuit 50 that outputs a DC voltage, and a load 60 that is connected to a secondary output.

[0004] Push-pull type step-up transformer 10 '
Is a primary winding 11 'having a core 13' at the center, an intermediate terminal on the outer peripheral side of the core 13 ', and a secondary winding 121 wound on the outer peripheral side of the primary winding 11' via an insulator. '. In the circuit having the above configuration, a battery of about 12 V is usually used as a primary power supply, so that it is necessary to increase a primary input current in order to secure a secondary output.

[0005] As a result, the heat loss of the primary winding becomes excessive and the secondary output is naturally limited. In particular, the intermediate terminal uses a relatively thin copper wire (winding) structurally, so that the output on the secondary side is greatly limited. For this reason, the conventional push-pull type step-up transformer cannot output a secondary output of about 10 A at 300 to 350 V (primary input is 300 to 400 A at 12 V).

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the heat loss due to the primary winding of a push-pull type step-up transformer and to increase the secondary output capacity.

[0007]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a conductor plate such as a bus bar having an integral intermediate terminal is used as a primary winding of a push-pull type step-up transformer. By inserting and winding the secondary winding on the inner peripheral side of the primary winding conductor via an insulator, it is possible to apply a large current to the primary winding conductor. According to the second aspect of the present invention, the primary winding conductor is bent into a cylindrical shape, so that the conversion efficiency of the transformer is increased and the primary input for the same secondary output can be reduced.

According to the third aspect of the present invention, the component mounting portion is formed by integrally forming a portion for mounting other components of the switching electronic circuit on the conductor plate forming the primary winding and the primary intermediate terminal. And the primary side input can be further reduced. Further, in the invention according to claim 4, by fixing the conductor plates constituting the primary winding with an electric insulating material, a portion bent into a cylindrical shape as the primary winding and a linear portion extending continuously. Can have a mechanically stable structure.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment described below is an example, and according to a person having ordinary skill in the art, other embodiments may be used without departing from the technical scope of the present invention. Is easy to implement. The block diagram showing the push-pull type step-up switching power supply circuit shown in FIG. 7 is commonly used in the present application except for the arrangement of each element constituting the push-pull type step-up transformer and the switching power supply circuit. In denoting the configuration of the present application, reference numbers related to the push-pull type step-up transformer are shown without dashes (').

FIG. 1 is an exploded view of a main part showing an embodiment of a push-pull type step-up transformer 10 according to the present invention. In FIG. 1, the primary winding conductor 11 includes an intermediate terminal 111, an intermediate terminal connection 114, a terminal hole 115, left and right primary winding conductors 112 and 113 integrated with the intermediate terminal, and left and right primary windings. It is composed of straight portions 1122 and 1311, which are left and right terminal portions integrated with the conductor portion. Upper electrode part 1
Reference numeral 4 denotes a primary winding conductor 1 with an electric insulating sheet 15 interposed therebetween.
It is arranged on the upper surface of the first intermediate terminal section 111 and is fixed to the primary winding conductor 11 with an electrically insulating resin screw or the like.

The upper electrode portion 14 functions as a connection terminal such as screwing or soldering when various switching circuit elements such as a capacitor and a transistor are electrically connected to the primary winding conductor 11. The right primary winding conductor 113 of the primary winding conductor 11 has a cylindrical bent portion as shown, and extends integrally with the straight portion 1131. Similarly,
The left primary winding conductor 112 has a cylindrical bent portion as shown, and extends integrally with the straight portion 1122. Insulation sheets 16 and 17 are inserted into portions where the straight portions 1131 and 1122 overlap the intermediate terminal portion 111 of the primary winding conductor 11 to prevent an electrical short circuit.

The secondary winding 12 is provided with winding start and end draw-out portions 124 and 125, and is wound around a coil portion 121 made of a normal circular electric wire wound around the bobbin portion 122 and an outer peripheral portion of the coil portion 121. The left and right primary winding conductor portions 11 of the primary winding conductor 11 are provided with an insulating sheet 126 to be layered.
3 and 112, and is fixed to the opposed single flange portion 123 by means such as adhesion. Further, E-type ferrite cores 131 are inserted into the center hole of the bobbin 122 from left and right. The outer peripheral portions of the E-type ferrite cores 131, 131 are fixed with a metal band, an adhesive tape, or the like, and constitute a closed magnetic circuit.

FIG. 2 shows the primary winding conductor 11 and FIG.
Here, a clamp member 70 made of a flexible electric insulating material such as a resin is omitted for clarity. Also, a plurality of holes in the primary winding conductor 11 in the figure are holes, not shown in FIG. 1, for screwing various semiconductor elements constituting the switching circuit and connecting them with solder or the like. is there.
The right primary-side conductor 113 is bent downward from above toward the plane of the paper, and is integrally connected to the linear part 1131. The left primary-side conductor 112 is bent upward from below toward the plane of the paper, and It is continuous with the part 1131 integrally.

The linear portions 1131 and 1122 are fixed in close contact with the conductor portion on the upper surface of the paper by the clamp member 70 with the insulating sheets 16 and 17 interposed therebetween. Clamp member 70
Has a U-shaped portion shown in FIG. 6, and includes a primary winding conductor 11 and a straight portion 1131 or 1122 in the U-shaped portion.
Are fixed by elastic force, and both are fixed. Instead of the clamp member 70, various fixing means such as acrylic screws can be used while maintaining the insulating property. The plurality of circular shapes shown in the intermediate terminal portion 111 and the linear portions 1131 and 1122 in the drawing are holes for connecting various semiconductor components constituting the switching circuit with screws and soldering.

FIG. 3 shows the primary winding conductor 1 shown in FIG.
FIG. 1 is a development view of FIG. FIG.
3 is a front view showing the upper electrode unit 14. FIG. Similarly, FIG.
Here, a plurality of holes for screwing and connecting various semiconductor elements constituting the switching circuit, which are omitted for clarity, are shown.

FIG. 5 is a front view of the push-pull type step-up transformer 10, and shows a clamp member 70 which is omitted in FIG. 1 for clarity. The outer peripheral portion of the E-type ferrite core 131 inserted into the bobbin portion 122 is fixed with a metal band, an adhesive tape, or the like. The arrows in the figure indicate the left and right primary winding conductors 113 from the intermediate terminal 111,
The direction of the current flowing to 114 is shown. FIG. 6 shows the shape of the clamp member 70. The clamp member 70 is integrally formed from a flexible electric insulating material such as an acrylic material by resin molding or the like.

In the above embodiment of the present invention, the left and right primary winding conductor portions 113 and 114 of the primary winding conductor 11 have a cylindrical shape, but the magnetic efficiency with the secondary coil is not reduced. Irregular shapes such as rectangles and ellipses are possible.

[0018]

As is apparent from the above description, according to the first aspect of the present invention, a conductor plate such as a bus bar having an integrated intermediate terminal is used as the primary winding of the push-pull type step-up transformer. By inserting and winding the secondary winding on the inner peripheral side of the primary winding conductor via an insulator, a large current can be supplied to the primary winding conductor. Claim 2
According to the invention, the primary winding conductor is bent into a cylindrical shape, so that the conversion efficiency of the transformer is increased and the primary input for the same secondary output can be reduced.

According to the third aspect of the present invention, the component for mounting the other components of the switching electronic circuit is integrally formed on the conductor plate forming the primary winding and the primary intermediate terminal. The voltage drop of the mounting part is reduced, and the primary-side input can be further reduced. Still further, according to the invention of claim 4, by fixing the conductor plates to each other with an electric insulating material, a cylindrically bent portion and a continuous linear portion as a primary winding are mechanically stable integrated structure. It becomes possible.

[Brief description of the drawings]

FIG. 1 is an exploded view of a main part showing an embodiment of the present invention.

FIG. 2 is a partial front view showing a primary winding conductor.

FIG. 3 is a development view of a primary winding conductor shown in FIG. 2;

FIG. 4 is a front view showing an upper electrode unit.

FIG. 5 is a front view showing a push-pull type step-up transformer.

FIG. 6 is a front view and a side view showing a clamp member.

FIG. 7 is a block diagram showing a push-pull type boost switching power supply circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Push-pull type step-up transformer 11 Primary winding conductor 12 Secondary winding part 15, 16, 17 Insulating sheet 70 Clamp member 111 Intermediate terminal part 112, 113 Primary winding conductor part 1122, 1311 Linear part 114 Intermediate terminal Connecting part 115 Terminal hole 121 Coil part 122 Bobbin part 123 Single flange part 126 Insulating sheet 131 E-type ferrite core

Claims (4)

[Claims] In a push-pull type step-up transformer having an intermediate terminal on a primary side, a primary winding and a primary intermediate terminal are formed by an integral conductor plate, and a secondary winding constitutes a primary winding. A push-pull type step-up transformer, which is housed in the conductor plate. 2. The method according to claim 1, wherein the primary winding comprises:
A push-pull type step-up transformer comprising a cylindrical portion formed on a part of the conductor plate. 3. The device according to claim 1, wherein the conductor plate integrally forms a part for mounting another component of the switching electronic circuit connected to the push-pull type step-up transformer. Push-pull type step-up transformer. 4. An intermediate terminal on a primary side, a primary winding and a primary intermediate terminal are formed by an integral conductor plate, a primary winding portion has a cylindrical shape portion, and a secondary winding is formed. In a push-pull type step-up transformer housed in a conductor plate constituting a primary side winding, a linear part and a primary side intermediate terminal part continuous from the primary side winding part are interposed with an electric insulating material by an electric insulating member. Push-pull type step-up transformer characterized by being mechanically fixed.